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Suggested Citation:"Neurosurgical Implications." National Research Council. 1957. Peripheral Nerve Regeneration: A Follow-Up Study of 3,656 World War II Injuries. Washington, DC: The National Academies Press. doi: 10.17226/18485.
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Suggested Citation:"Neurosurgical Implications." National Research Council. 1957. Peripheral Nerve Regeneration: A Follow-Up Study of 3,656 World War II Injuries. Washington, DC: The National Academies Press. doi: 10.17226/18485.
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Page 570
Suggested Citation:"Neurosurgical Implications." National Research Council. 1957. Peripheral Nerve Regeneration: A Follow-Up Study of 3,656 World War II Injuries. Washington, DC: The National Academies Press. doi: 10.17226/18485.
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Suggested Citation:"Neurosurgical Implications." National Research Council. 1957. Peripheral Nerve Regeneration: A Follow-Up Study of 3,656 World War II Injuries. Washington, DC: The National Academies Press. doi: 10.17226/18485.
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Suggested Citation:"Neurosurgical Implications." National Research Council. 1957. Peripheral Nerve Regeneration: A Follow-Up Study of 3,656 World War II Injuries. Washington, DC: The National Academies Press. doi: 10.17226/18485.
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Page 573
Suggested Citation:"Neurosurgical Implications." National Research Council. 1957. Peripheral Nerve Regeneration: A Follow-Up Study of 3,656 World War II Injuries. Washington, DC: The National Academies Press. doi: 10.17226/18485.
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Suggested Citation:"Neurosurgical Implications." National Research Council. 1957. Peripheral Nerve Regeneration: A Follow-Up Study of 3,656 World War II Injuries. Washington, DC: The National Academies Press. doi: 10.17226/18485.
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Page 575
Suggested Citation:"Neurosurgical Implications." National Research Council. 1957. Peripheral Nerve Regeneration: A Follow-Up Study of 3,656 World War II Injuries. Washington, DC: The National Academies Press. doi: 10.17226/18485.
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Page 576
Suggested Citation:"Neurosurgical Implications." National Research Council. 1957. Peripheral Nerve Regeneration: A Follow-Up Study of 3,656 World War II Injuries. Washington, DC: The National Academies Press. doi: 10.17226/18485.
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Page 577
Suggested Citation:"Neurosurgical Implications." National Research Council. 1957. Peripheral Nerve Regeneration: A Follow-Up Study of 3,656 World War II Injuries. Washington, DC: The National Academies Press. doi: 10.17226/18485.
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Suggested Citation:"Neurosurgical Implications." National Research Council. 1957. Peripheral Nerve Regeneration: A Follow-Up Study of 3,656 World War II Injuries. Washington, DC: The National Academies Press. doi: 10.17226/18485.
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Suggested Citation:"Neurosurgical Implications." National Research Council. 1957. Peripheral Nerve Regeneration: A Follow-Up Study of 3,656 World War II Injuries. Washington, DC: The National Academies Press. doi: 10.17226/18485.
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Page 580
Suggested Citation:"Neurosurgical Implications." National Research Council. 1957. Peripheral Nerve Regeneration: A Follow-Up Study of 3,656 World War II Injuries. Washington, DC: The National Academies Press. doi: 10.17226/18485.
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Suggested Citation:"Neurosurgical Implications." National Research Council. 1957. Peripheral Nerve Regeneration: A Follow-Up Study of 3,656 World War II Injuries. Washington, DC: The National Academies Press. doi: 10.17226/18485.
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Suggested Citation:"Neurosurgical Implications." National Research Council. 1957. Peripheral Nerve Regeneration: A Follow-Up Study of 3,656 World War II Injuries. Washington, DC: The National Academies Press. doi: 10.17226/18485.
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Suggested Citation:"Neurosurgical Implications." National Research Council. 1957. Peripheral Nerve Regeneration: A Follow-Up Study of 3,656 World War II Injuries. Washington, DC: The National Academies Press. doi: 10.17226/18485.
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Suggested Citation:"Neurosurgical Implications." National Research Council. 1957. Peripheral Nerve Regeneration: A Follow-Up Study of 3,656 World War II Injuries. Washington, DC: The National Academies Press. doi: 10.17226/18485.
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Page 585
Suggested Citation:"Neurosurgical Implications." National Research Council. 1957. Peripheral Nerve Regeneration: A Follow-Up Study of 3,656 World War II Injuries. Washington, DC: The National Academies Press. doi: 10.17226/18485.
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Page 586
Suggested Citation:"Neurosurgical Implications." National Research Council. 1957. Peripheral Nerve Regeneration: A Follow-Up Study of 3,656 World War II Injuries. Washington, DC: The National Academies Press. doi: 10.17226/18485.
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Page 587
Suggested Citation:"Neurosurgical Implications." National Research Council. 1957. Peripheral Nerve Regeneration: A Follow-Up Study of 3,656 World War II Injuries. Washington, DC: The National Academies Press. doi: 10.17226/18485.
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Page 588
Suggested Citation:"Neurosurgical Implications." National Research Council. 1957. Peripheral Nerve Regeneration: A Follow-Up Study of 3,656 World War II Injuries. Washington, DC: The National Academies Press. doi: 10.17226/18485.
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Page 589
Suggested Citation:"Neurosurgical Implications." National Research Council. 1957. Peripheral Nerve Regeneration: A Follow-Up Study of 3,656 World War II Injuries. Washington, DC: The National Academies Press. doi: 10.17226/18485.
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Page 590
Suggested Citation:"Neurosurgical Implications." National Research Council. 1957. Peripheral Nerve Regeneration: A Follow-Up Study of 3,656 World War II Injuries. Washington, DC: The National Academies Press. doi: 10.17226/18485.
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Page 591
Suggested Citation:"Neurosurgical Implications." National Research Council. 1957. Peripheral Nerve Regeneration: A Follow-Up Study of 3,656 World War II Injuries. Washington, DC: The National Academies Press. doi: 10.17226/18485.
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Page 592
Suggested Citation:"Neurosurgical Implications." National Research Council. 1957. Peripheral Nerve Regeneration: A Follow-Up Study of 3,656 World War II Injuries. Washington, DC: The National Academies Press. doi: 10.17226/18485.
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Page 593
Suggested Citation:"Neurosurgical Implications." National Research Council. 1957. Peripheral Nerve Regeneration: A Follow-Up Study of 3,656 World War II Injuries. Washington, DC: The National Academies Press. doi: 10.17226/18485.
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Page 594
Suggested Citation:"Neurosurgical Implications." National Research Council. 1957. Peripheral Nerve Regeneration: A Follow-Up Study of 3,656 World War II Injuries. Washington, DC: The National Academies Press. doi: 10.17226/18485.
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Page 595
Suggested Citation:"Neurosurgical Implications." National Research Council. 1957. Peripheral Nerve Regeneration: A Follow-Up Study of 3,656 World War II Injuries. Washington, DC: The National Academies Press. doi: 10.17226/18485.
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Page 596
Suggested Citation:"Neurosurgical Implications." National Research Council. 1957. Peripheral Nerve Regeneration: A Follow-Up Study of 3,656 World War II Injuries. Washington, DC: The National Academies Press. doi: 10.17226/18485.
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Page 597
Suggested Citation:"Neurosurgical Implications." National Research Council. 1957. Peripheral Nerve Regeneration: A Follow-Up Study of 3,656 World War II Injuries. Washington, DC: The National Academies Press. doi: 10.17226/18485.
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Page 598
Suggested Citation:"Neurosurgical Implications." National Research Council. 1957. Peripheral Nerve Regeneration: A Follow-Up Study of 3,656 World War II Injuries. Washington, DC: The National Academies Press. doi: 10.17226/18485.
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Page 599
Suggested Citation:"Neurosurgical Implications." National Research Council. 1957. Peripheral Nerve Regeneration: A Follow-Up Study of 3,656 World War II Injuries. Washington, DC: The National Academies Press. doi: 10.17226/18485.
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Page 600
Suggested Citation:"Neurosurgical Implications." National Research Council. 1957. Peripheral Nerve Regeneration: A Follow-Up Study of 3,656 World War II Injuries. Washington, DC: The National Academies Press. doi: 10.17226/18485.
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Page 601
Suggested Citation:"Neurosurgical Implications." National Research Council. 1957. Peripheral Nerve Regeneration: A Follow-Up Study of 3,656 World War II Injuries. Washington, DC: The National Academies Press. doi: 10.17226/18485.
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Page 602
Suggested Citation:"Neurosurgical Implications." National Research Council. 1957. Peripheral Nerve Regeneration: A Follow-Up Study of 3,656 World War II Injuries. Washington, DC: The National Academies Press. doi: 10.17226/18485.
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Page 603
Suggested Citation:"Neurosurgical Implications." National Research Council. 1957. Peripheral Nerve Regeneration: A Follow-Up Study of 3,656 World War II Injuries. Washington, DC: The National Academies Press. doi: 10.17226/18485.
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Page 604
Suggested Citation:"Neurosurgical Implications." National Research Council. 1957. Peripheral Nerve Regeneration: A Follow-Up Study of 3,656 World War II Injuries. Washington, DC: The National Academies Press. doi: 10.17226/18485.
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Page 605
Suggested Citation:"Neurosurgical Implications." National Research Council. 1957. Peripheral Nerve Regeneration: A Follow-Up Study of 3,656 World War II Injuries. Washington, DC: The National Academies Press. doi: 10.17226/18485.
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Page 606
Suggested Citation:"Neurosurgical Implications." National Research Council. 1957. Peripheral Nerve Regeneration: A Follow-Up Study of 3,656 World War II Injuries. Washington, DC: The National Academies Press. doi: 10.17226/18485.
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Page 607
Suggested Citation:"Neurosurgical Implications." National Research Council. 1957. Peripheral Nerve Regeneration: A Follow-Up Study of 3,656 World War II Injuries. Washington, DC: The National Academies Press. doi: 10.17226/18485.
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Page 608
Suggested Citation:"Neurosurgical Implications." National Research Council. 1957. Peripheral Nerve Regeneration: A Follow-Up Study of 3,656 World War II Injuries. Washington, DC: The National Academies Press. doi: 10.17226/18485.
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Page 609
Suggested Citation:"Neurosurgical Implications." National Research Council. 1957. Peripheral Nerve Regeneration: A Follow-Up Study of 3,656 World War II Injuries. Washington, DC: The National Academies Press. doi: 10.17226/18485.
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Page 610
Suggested Citation:"Neurosurgical Implications." National Research Council. 1957. Peripheral Nerve Regeneration: A Follow-Up Study of 3,656 World War II Injuries. Washington, DC: The National Academies Press. doi: 10.17226/18485.
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Page 611
Suggested Citation:"Neurosurgical Implications." National Research Council. 1957. Peripheral Nerve Regeneration: A Follow-Up Study of 3,656 World War II Injuries. Washington, DC: The National Academies Press. doi: 10.17226/18485.
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Page 612
Suggested Citation:"Neurosurgical Implications." National Research Council. 1957. Peripheral Nerve Regeneration: A Follow-Up Study of 3,656 World War II Injuries. Washington, DC: The National Academies Press. doi: 10.17226/18485.
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Page 613
Suggested Citation:"Neurosurgical Implications." National Research Council. 1957. Peripheral Nerve Regeneration: A Follow-Up Study of 3,656 World War II Injuries. Washington, DC: The National Academies Press. doi: 10.17226/18485.
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Page 614
Suggested Citation:"Neurosurgical Implications." National Research Council. 1957. Peripheral Nerve Regeneration: A Follow-Up Study of 3,656 World War II Injuries. Washington, DC: The National Academies Press. doi: 10.17226/18485.
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Page 615
Suggested Citation:"Neurosurgical Implications." National Research Council. 1957. Peripheral Nerve Regeneration: A Follow-Up Study of 3,656 World War II Injuries. Washington, DC: The National Academies Press. doi: 10.17226/18485.
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Page 616
Suggested Citation:"Neurosurgical Implications." National Research Council. 1957. Peripheral Nerve Regeneration: A Follow-Up Study of 3,656 World War II Injuries. Washington, DC: The National Academies Press. doi: 10.17226/18485.
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Page 617
Suggested Citation:"Neurosurgical Implications." National Research Council. 1957. Peripheral Nerve Regeneration: A Follow-Up Study of 3,656 World War II Injuries. Washington, DC: The National Academies Press. doi: 10.17226/18485.
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Page 618
Suggested Citation:"Neurosurgical Implications." National Research Council. 1957. Peripheral Nerve Regeneration: A Follow-Up Study of 3,656 World War II Injuries. Washington, DC: The National Academies Press. doi: 10.17226/18485.
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Suggested Citation:"Neurosurgical Implications." National Research Council. 1957. Peripheral Nerve Regeneration: A Follow-Up Study of 3,656 World War II Injuries. Washington, DC: The National Academies Press. doi: 10.17226/18485.
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Page 620
Suggested Citation:"Neurosurgical Implications." National Research Council. 1957. Peripheral Nerve Regeneration: A Follow-Up Study of 3,656 World War II Injuries. Washington, DC: The National Academies Press. doi: 10.17226/18485.
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Page 621
Suggested Citation:"Neurosurgical Implications." National Research Council. 1957. Peripheral Nerve Regeneration: A Follow-Up Study of 3,656 World War II Injuries. Washington, DC: The National Academies Press. doi: 10.17226/18485.
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Page 622
Suggested Citation:"Neurosurgical Implications." National Research Council. 1957. Peripheral Nerve Regeneration: A Follow-Up Study of 3,656 World War II Injuries. Washington, DC: The National Academies Press. doi: 10.17226/18485.
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Suggested Citation:"Neurosurgical Implications." National Research Council. 1957. Peripheral Nerve Regeneration: A Follow-Up Study of 3,656 World War II Injuries. Washington, DC: The National Academies Press. doi: 10.17226/18485.
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Page 624
Suggested Citation:"Neurosurgical Implications." National Research Council. 1957. Peripheral Nerve Regeneration: A Follow-Up Study of 3,656 World War II Injuries. Washington, DC: The National Academies Press. doi: 10.17226/18485.
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Page 625
Suggested Citation:"Neurosurgical Implications." National Research Council. 1957. Peripheral Nerve Regeneration: A Follow-Up Study of 3,656 World War II Injuries. Washington, DC: The National Academies Press. doi: 10.17226/18485.
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Page 626
Suggested Citation:"Neurosurgical Implications." National Research Council. 1957. Peripheral Nerve Regeneration: A Follow-Up Study of 3,656 World War II Injuries. Washington, DC: The National Academies Press. doi: 10.17226/18485.
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Page 627
Suggested Citation:"Neurosurgical Implications." National Research Council. 1957. Peripheral Nerve Regeneration: A Follow-Up Study of 3,656 World War II Injuries. Washington, DC: The National Academies Press. doi: 10.17226/18485.
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Page 628
Suggested Citation:"Neurosurgical Implications." National Research Council. 1957. Peripheral Nerve Regeneration: A Follow-Up Study of 3,656 World War II Injuries. Washington, DC: The National Academies Press. doi: 10.17226/18485.
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Page 629
Suggested Citation:"Neurosurgical Implications." National Research Council. 1957. Peripheral Nerve Regeneration: A Follow-Up Study of 3,656 World War II Injuries. Washington, DC: The National Academies Press. doi: 10.17226/18485.
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Page 630
Suggested Citation:"Neurosurgical Implications." National Research Council. 1957. Peripheral Nerve Regeneration: A Follow-Up Study of 3,656 World War II Injuries. Washington, DC: The National Academies Press. doi: 10.17226/18485.
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Page 631
Suggested Citation:"Neurosurgical Implications." National Research Council. 1957. Peripheral Nerve Regeneration: A Follow-Up Study of 3,656 World War II Injuries. Washington, DC: The National Academies Press. doi: 10.17226/18485.
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Page 632
Suggested Citation:"Neurosurgical Implications." National Research Council. 1957. Peripheral Nerve Regeneration: A Follow-Up Study of 3,656 World War II Injuries. Washington, DC: The National Academies Press. doi: 10.17226/18485.
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Page 633
Suggested Citation:"Neurosurgical Implications." National Research Council. 1957. Peripheral Nerve Regeneration: A Follow-Up Study of 3,656 World War II Injuries. Washington, DC: The National Academies Press. doi: 10.17226/18485.
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Page 634
Suggested Citation:"Neurosurgical Implications." National Research Council. 1957. Peripheral Nerve Regeneration: A Follow-Up Study of 3,656 World War II Injuries. Washington, DC: The National Academies Press. doi: 10.17226/18485.
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Page 635
Suggested Citation:"Neurosurgical Implications." National Research Council. 1957. Peripheral Nerve Regeneration: A Follow-Up Study of 3,656 World War II Injuries. Washington, DC: The National Academies Press. doi: 10.17226/18485.
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Page 636
Suggested Citation:"Neurosurgical Implications." National Research Council. 1957. Peripheral Nerve Regeneration: A Follow-Up Study of 3,656 World War II Injuries. Washington, DC: The National Academies Press. doi: 10.17226/18485.
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Suggested Citation:"Neurosurgical Implications." National Research Council. 1957. Peripheral Nerve Regeneration: A Follow-Up Study of 3,656 World War II Injuries. Washington, DC: The National Academies Press. doi: 10.17226/18485.
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Below is the uncorrected machine-read text of this chapter, intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text of each book. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.

Chapter XII NEUROSURGICAL IMPLICATIONS Barnes Woodhall, Frank E. Nulsen, James C. White, and Loyal Davis A. INTRODUCTION A great mass of pertinent data has been presented in the body of this study of peripheral nerve regeneration. It is now necessary to attempt an interpretation of these data in terms of practical surgical management. A firm realization exists that the concept of treatment by hospital echelon, so clearly seen in World War II, has now become largely obsolete, or at least modified to a great extent by more rapid evacuation of patients. No possible fresh approach to this subject, however, can alter the lessons of the past. These have shown in a most convincing fashion that: (1) no ex- pectant attitude in the treatment of peripheral nerve injury can be main- tained unless supported by objective and accurate longitudinal observations; (2) there exists a demonstrable relationship between time of iajury and onset of appropriate therapy on the one hand and the extent of nerve regeneration on the other; and (3) men with peripheral nerve injuries can be rehabilitated adequately only through the means of specialized neuro- surgical treatment. In the absence of some fundamental contribution to the control of the reaction of connective tissue to injury, which constitutes the essential barrier to peripheral nerve regeneration, the following analysis of management of war injuries to peripheral nerves can be considered as valid as can be fashioned from the observed facts. B. MANAGEMENT IN FORWARD AREAS 1. Recognition of Peripheral Nerve Involvement The surgical task in a forward area is not conducive to the recognition and early management of peripheral nerve injury and rightly so. Here the primary surgical design has to do with the preservation of life, and this demand upon the surgeon is often a great one (14). When possible, how- ever, the forward surgeon should look upon himself as the first agent in a potential series of surgical enterprises and, in this function, seek evidence of peripheral nerve injury in all extremity wounds. Simple tests are avail- able for the recognition of nerve involvement for both upper and lower extremity, even if the limb be immobilized in a cast. The testing pro- cedures may be listed as follows for the major peripheral nerves. 569

Ulnar nerve. Loss of sensitivity to painful stimuli over the distal phalanx of the little or fifth finger. Median nerve. Loss of sensitivity to painful stimuli over the distal phalanx of the index or second finger. Radial nerve. Loss of ability to extend the wrist (wrist-drop), inability to extend the thumb and abduct the thumb in the "thumbs up" position. Sensory loss is variable. Wrist and lower forearm wounds may involve tendons directly and make such testing invalid. Brachial plexus. Recognized by the position of the wound and the in- volvement of component nerves of the upper extremity. Peroneal nerve. Inability to dorsiflex the ankle and the big toe (foot-drop). The sensory loss is inconstant. Tibial nerve. Loss of plantar flexion of ankle and big toe. Sensory loss over the sole of the foot is constant and may be the only indication of tibial involvement in wounds below the middle third of the calf. Sciatic nerve. The high location of the wound with either peroneal or tibial or combined nerve involvement. Characteristic hand postures may be observed immediately after wound- ing but they are not as well defined as they may be when muscle atrophy and shortening have occurred. 2. Immediate or Emergency Treatment of Peripheral Nerve Wounds These data have shown that 92 percent of the nerve injuries whose re- generation has been studied were caused by battle wounds. The remainder were due to accidental or civilian type injuries. In battle wounds caused by high velocity missiles, immediate or emergency peripheral nerve sur- gery is contraindicated, with but a single exception. This exception is found in the rare case of an expanding hematoma, the precursor of a false aneurysm, with progressive peripheral nerve dysfunction caused by pressure. These data have shown conclusively that, even in the best hands, the emergency suture of war wounds of peripheral nerves is followed by a failure to regenerate in over 50 percent of cases. If the nerve injury is visible without further nerve dissection at the time of wound debridement, its appearance should be described as accu- rately as possible in terms of complete nerve division, of partial nerve division with an estimate of the cross section involved or of continuity of nerve segments. Even if the examinations noted have indicated the presence of a major nerve segment injury, undue exploration for the lesion at the time of debridement is contraindicated and it is likewise not indicated at the time of secondary wound closure. In cases of complete nerve divi- sion, approximation or coaptation sutures may prevent some retraction of divided nerve ends. This is usually not an important issue since so much nerve tissue is customarily lost in war wounds. If such a suture is used, care must be taken not to damage normal nerve trunk and it is mandatory 570

that the word "suture" be not loosely used in the medical record without its qualifying terms. Packs in contact with peripheral nerve tissue may be harmful. Of primary importance in the initial time period following injury are: (1) identification and recording of the clinical characteristics of the nerve injury; and (2) description of the findings at debridement if the injured nerve is visualized. 3. Early Splinting of Paralyzed Muscles Continuous splinting should never be carried out as a form of treatment of a peripheral nerve injury. Such splinting or casting is indicated only by fracture or extensive soft tissue wounds near working joint surfaces. When continuously splinted, nerve injuries will show severe joint fixation, particularly of wrist, finger, and thumb articulations. When such casting must be done, the distal half of the hand and fingers should be left free. Intermittent splinting of peripheral nerve injury is indicated in two specific injuries. The first is the complete wrist-drop of radial nerve paralysis which should be supported by a light cast, splint, or brace which holds only the wrist in dorsiflexion. The patient will feel more comfortable and will use the fingers and thumb for useful function with such support. Support of the proximal phalanges may lead to ankylosis of the metacarpophalangeal joints in partial extension, a severe and often permanent disability. Pa- tients will discard more elaborate braces because of their inability to use the hand for grasping. The end results of regeneration have been good in patients with only the wrist supported. The wrist-drop support should be worn at night but removed intermittently during the day and a full range of wrist movement carried out passively by the patient. The second spe- cific injury requiring intermittent splinting is one involving the sciatic nerve or the peroneal nerve with foot-drop, for which the foot should be splinted in a position of dorsiflexion. The posterior splint should be light so that the patient may be ambulatory with crutches, until such time as he can bear weight and use the ordinary spring brace. The splint must be removed intermittently during the day, both to permit full passive ankle movement and to check for early signs of pressure sores on the heel or sole. Such pressure lesions may develop with posterior tibial nerve involvement alone. Ischemic paralysis of the median nerve with a tight cast, for instance, and peroneal nerve palsy from local cast pressure are common sequelae of poorly designed or unwatched continuous casting. The corollary to the proper early splinting of nerve injuries is the contin- uous effort directed toward mobilization of joints by physiotherapy, whether by the physiotherapist or, of greater importance, by the patient himself. C. EVALUATION AND DEFINITIVE MANAGEMENT 1. Introduction As already pointed out, evidence gathered from personnel of the auxiliary surgical teams of World War II or the MASH units of the Korean campaign 371

suggests that the forward surgeon cannot be oriented in detail to the problem of peripheral nerve injury. This statement is not to be construed as a measure of their reluctance to be so oriented. It seems clear that, unless survival of an extremity is threatened, the actual demands of neck, chest, and abdomi- nal wounds upon their time and energies are very pressing. Even the simple tests that have been outlined are usually omitted and the demonstration of nerve disruption at the time of debridement is, of course, purely fortuitous. Such inevitable circumstances emphasize sharply the need for the study and exact recording of neurological changes in the wounded extremity when the casualty reaches a fixed installation. Here, for the first time, in the presence of complete clinical paralysis, the surgeon encounters the task of answering the fundamental question, whether this apparent complete nerve paralysis will go on to spontaneous resolution or some degree of return of function better than that which can be gained by suture, or whether an incapaci- tating paralysis will continue as a result of actual nerve segment disruption. No conservative or expectant attitude can be tolerated toward the return of peripheral nerve function in war injuries, unless main- tained by objective evidence studied in terms of time after injury. Only a laborious dissection of the factors that have been presented in preceding chapters can even approximate an answer to this issue. The statistical evidence concerned with the number of complete anatom- ical disruptions of nerve tissue as a result of war injury as compared to par- tial injury or axonal injury with their better prognosis is conflicting. This conflict is in all probability dependent upon the variable pathological forms, perhaps unequally recognized, and upon when after injury the observations were noted. Perhaps the most succinct statement in this regard has been made by Seddon (68), a statement particularly appealing to surgeons who tend to judge an issue in "black and white"terms, since they must inevitably func- tion in such terms. "A more difficult question is what to do in the case where a degenerative lesion is present and where the anatomical state of the nerve has not been disclosed during treatment of the wound. Are we justified, as in the case of nerve injuries due to closed fractures, in waiting in the hope that spon- taneous recovery will occur?" and "One of the most curious inconsistencies in the whole story of the surgery of peripheral nerve injuries is that it has been generally accepted that primary suture is the ideal form of nerve repair. It has, at the same time, been widely held that in dealing with nerve injuries due to war wounds repair of the nerve is not a matter of urgency, and that in a good proportion of cases an expectant attitude may properly be adopted. If, as we all agree, primary suture is the theoretical ideal, then it follows that in cases requiring secondary suture repair should be undertaken at the earliest convenient time." Such a policy demands an exploratory operation of every case of complete paralysis due to an open or gunshot wound in which the anatomical status of the nerve segment is not known. What evidence is available in terms 571

of gross tissue injury to indicate that such an exploration is indicated? The Oxford group, in support of this thesis, found complete or virtually complete loss of nerve segment continuity in 50 percent of their cases. Spurling and Woodhall (75) studied operative findings in 2,873 cases of complete paralysis and found nerve segment division in 54 percent of cases; the remainder represented neuromas or nerve contusions in contin- uity. The observations made were recorded at an average time period of 39 days after wounding. Studying the same matter under somewhat similar circumstances in a specialized center, Foerster (24) found complete nerve division in 44 percent of his cases. "Thus it may be argued," states Seddon, "as the Americans and the writer have done, that with an equal chance of finding a divided nerve the surgeon is justified in subjecting his patient to an operation which may be unnecessary." There is considerable evidence to the contrary and this evidence needs careful scrutiny since it is well documented. Sunderland (77), studying 339 cases of nerve injury rather carefully segregated in purely Australian hands, found that 68 percent of these cases recovered spontaneously, and the statement is made that this regeneration was better than that to be expected from suture. Sunderland's roster was apparently under recorded contact from the time of wounding and included both partial and complete nerve paralyses and also included some types of accidental wounding. Sunderland states that these findings are supported by Foerster, and by Tinel and Benisty. Tinel (79) stated "* * * according to our personal statistics, we may estimate at between 60 and 70 percent, approximately, the number of spontaneous regenerations without surgical intervention; at the same time, there are a certain number of these, between 10 and 20 percent, which in our opinion would have gained by such an intervention." Livingston (44) studied 132 patients in World War II at a time period of 3 months postinjury. Their records were uniformly well documented, they had been injured by high velocity missiles, and they had been operated upon by trained per- sonnel as elective procedures. Of these 132 patients, 3 had irreparable injuries, 20 proved to have complete nerve division at operation, and 4 partially divided nerves that required suture. The remainder, roughly 80 percent, appeared at this very early time period at least to be recovering spontaneously. Strange as it may seem, definitive information on the incidence of peripheral nerve injury in World War II is lacking. Men are injured in myriad ways, and injuries to specific structures are also extremely variable. Unfortunately, the extent of injury to a peripheral nerve cannot be determined by gross inspection unless it be divided; nor can one reliably infer the extent of injury from the functional deficit. Sampling is con- ducted in various ways, ordinarily in more or less close association with therapy, and bias easily enters. To obtain a representative sample of peripheral nerve injuries, one must start with a sample of all WIA involving the extremities. If one samples at any point along the echelons of treatment one will encounter more or less opportunity for distortion. Depending on 573

how the sampling is done, disagreements will inevitably arise. On the basis of accredited sampling, there were 30,000 to 40,000 nerve injuries; at least 17 percent were treated by suture or graft and possibly as many as 26 percent (4). These varied and good expressions would indicate that the observed degrees of tissue injury are predicated upon the time at which the observa- tions are made after the inflicting trauma, the availability of longitudinal data, and the ability to recognize total or subtotal injury at the time of operation. There must be a substantial percentage of nerve injuries that are incomplete in terms of functional loss if seen shortly after the shock of injury. These present a problem of longitudinal observation that is in turn a weighing of the degree of spontaneous regeneration against what may be obtained, for instance, by resection and suture. Of more immediate concern is the adequate recognition of complete versus incomplete nerve paralysis, without regard to its pathological source, since among these cases will be found some percentage, as noted in the observations above, that may require operative intervention. They may be recognized by the following techniques of study. The same techniques are applicable to the complete, the incomplete, or the regenerating nerve injury. There appear to be two prerequisites for the proper diagnosis and treat- ment of peripheral nerve injury. These may be combined in the statement "careful repeated examinations carried out in a standardized fashion." In this way, data collected over any period of time by various observers may be readily and effectively compared. An outline of examination includes history taking, operative observations, pathological records, and tests of motor, sensory, autonomic and electrical properties of nerves and muscles which reduce descriptions to a minimum and convert results into numbers as far as possible. When such examinations must be formulated for practical use, their exposition should be restricted to a single page. Workable examination sheets may be constructed as follows: Form 1—History. The nerve casualty may now be considered placed at a more permanent installation than the MASH unit or any other forward resuscitation facility. This is the time for recording certain simple and basic data having to do with the date and time of injury and causative agent, the location of the wound, the immediate subjective responses of the patient to trauma, the operative procedures and observations of the forward surgeon, and the subsequent course of the patient prior to this first formal review of the alleged nerve injury. Form 2—Examination—Motor. Any examination of motor status presup- poses a knowledge of the anatomy and function of the muscles in the distri- bution of each nerve. Specifically, the examiner must know the origin and insertion of the muscle in question, its level of nerve supply, and the isolated, synergistic, and antagonistic functions it is capable of producing. Since an individual always uses a group of muscles to effectuate a functional movement, it is usually difficult to isolate any given muscle. It is also necessary to take into account the possibility that the patient can instinc- 574

tively but falsely effect any given motor performance by substituted or trick muscle movements. Anomalous innervation, particularly of intrinsic hand muscles, must also be kept in mind. These details of examination and the usual sources of error are won and kept in mind only under the pressure of constant usage. They must be recorded and have been in such texts as these: Haymaker and Woodhall, Peripheral Nerve Injuries, Second Edition (33); British MRC War Memorandum No. 7, Aid to \the Investigation of Peripheral Nerve Injuries (51); and Kendall and Kendall, Muscles, Testing and Function (35). Such monographs are not part of the usual scene of even the base wartime installation, particularly in the presence of heavy casualty loads. Form 2, however, may be initiated with a study of certain designated muscles. A standard group of muscles has been tested repeatedly by the study centers. These include representative muscles from proximal and distal groups which by their position or by the particular motion they perform are most reliably tested. The muscles for each nerve are listed and should be written in the examination sheet for the appropriate nerve. Ulnar Nerve Flexor carpi ulnaris Flexor digitorum profundus (fourth and fifth fingers) Abductor digit! quinti First dorsal interosseous Median Nerve Flexor carpi radial is Flexor digitorum profundus (index finger) Flexor pollicis longus Abductor pollicis brevis Opponens pollicis Radial Nerve Triceps Brachioradialis Extensor carpi radialis Extensor digitorum Extensor carpi ulnaris Abductor pollicis longus Extensor pollicis longus ct brevis Sciatic Nerve Proximal—Biceps fcmoris, scmimembranosus, scmitcndinosus Distal Tibial Nerve Gastrocnemius-soleus Tibialis posticus Flexor digitorum longus Flexor hallucis longus Intrinsic foot muscle (cupping of sole of foot) Peroneal Nerve Tibialis anticus Extensor digitorum longus Extensor hallucis longus Peroneus longus

Musculocutaneous Nerve Biceps brachii Axillary Nerve Deltoid Femoral Nerve Quadriceps femorU The choice of muscles made by the group concerned with the follow-up study is given on page 73. Further discussion of techniques of study is not necessary at this point since these matters have been covered indetail in the preceding data chapters. The purpose in hand will be served better by a survey of the problem of nerve regeneration as it was found in casualties of the Korean campaign. 2. Evaluation of Evidence For or Against Nerve Regeneration as an Indication for Resection and Suture.2" It should be clear that a real dilemma may exist in the choice of manage- ment of the early nerve lesion. If this lesion will not permit satisfactory regeneration, it is evident, from reference to the correlation between time of suture and end result, that this suture should be undertaken as early as possible. There would seem to be no arbitrary time limit—a suture at 1 month after injury does better than one at 2 months, and far better than one at 6 months where an average reduction of 30 percent in overall motor recovery may be expected. Such a reduction is clearly more critical in nerves which do badly, such as the ulnar or the peroneal, as well as in high lesions of any nerve. But regardless of individual situations, the statistics on the influence of delay can only result in a sense of urgency for every lesion, not only in order to shorten hospitalization by getting necessary treatment under way but also to achieve the best possible end results in a situation which has definite limitations. The urgency of accomplishing indicated sutures is offset by the certain limitations in regeneration which are imposed when suture is undertaken. Radical management of a nerve lesion should not be undertaken if there is any indication that a neuroma in continuity will permit greater regenera- tion than could be accomplished by its resection and suture. It must be remembered that roughly 75 percent of nerve lesions associated with initial total paralysis (in the military situation where the usual wounding agent is a high velocity missile) do not require suture and achieve an end result far better than could have been accomplished by suture. Fifty percent of this group showed no evidences of regeneration for such a long period that the nerve lesion was explored and the dissection of a contused nerve segment from surrounding scar tissue was usually referred to as neurolysis. Whether such a neurolysis constitutes a therapeutic measure which actually influences » This section is based on the Valley Forge series studied by Dr. Frank E. Nulsen, Dr. William J. Erdman, II, and Dr. Harry W. Slade. 576

the course of regeneration or should simply be considered a nerve explora- tion to establish that resection and suture were not indicated is highly debatable. Nevertheless, it is clear that both those lesions which recover so early that no exploration is undertaken and those which are subjected to lysis for the most part develop more complete regeneration than is seen in the suture group. On the other hand, an occasional patient subjected to no more definitive treatment than lysis fails to show the level of regeneration expected of suture in this location and an occasional lesion in continuity, subjected to resec- tion, shows histologic evidence of more distal neurotization than suture can achieve. The problem is one of accomplishing all indicated sutures as early as possible but only in those cases where spontaneous regeneration will be limited. Under ideal circumstances, negative explorations should be avoided or kept at a minimum, but this is chiefly a matter of expediency since the negative exploration is an innocuous procedure which does not affect the end result. In other words, if an exploration had only a 10 percent chance of resulting in the early accomplishment of an indicated suture, it would seem justified. Postponement would seem indicated only when a short additional interval of delay might allow for evidences of regeneration that would eliminate an unnecessary operative procedure. This last consideration would justify delay of most operative procedures until 1 month after injury because of the large proportion of spontaneous recoveries that become defined within this short period of waiting. More than 30 percent of initial total paralyses from high velocity missiles will be- come resolved as situations not requiring operation as early as 1 month after injury. This is an insufficient time for regeneration of any disrupted neuroma and must be attributed to the functional recovery of intact neu- rones that have suffered axonopraxis. Such early recovery, either motor or sensory, is especially favorable for, if the nerve trunk contains some axons that did not even degenerate, a major proportion of the degenerated fibers are probably capable of spontaneous regeneration. The kind of disruption that presents a permanent block to axonal regeneration cannot exist in a nerve segment with intact axons. This month's delay for sorting-out purposes would not be indicated if divided nerve ends had actually been visualized at the time of initial injury or if the configuration of the wound was such that the nerve trunk could not possibly have escaped severance. Nor would such delay be indicated in the simple laceration where the neuro- logical deficit can be assumed to be the result of actual severance of axon rather than the possible temporary result of concussion by a missile passing close to the nerve. Whether suture is indicated will usually be settled by the gross appearance of the lesion explored at the end of 1 month, when a clean wound and flexible joints make this feasible. However, when gross anatomical continuity exists even though there is obvious damage to the nerve segment, this is not the time to elect suture. Such neuroma in continuity problems will be found in over 50 percent of those early explora- tions and only subsequent observation will determine whether spontaneous 403930—57 39 577

regeneration is to offer a better result than can be expected from reoperation and suture. An evaluation of evidence for regeneration is therefore an important and necessary task for each nerve lesion until it defines itself as requiring no further operative procedures. In the early case sufficient evidence of regeneration is sought to preclude the necessity for operative exploration. In the neurolysed neuroma in continuity the nature of the lesion is defined, as time passes, as one which will show more or less recovery than can be provided by resection and suture. In the sutured case sufficient evidence for regeneration is compiled to remove any question that a sec- ondary suture might accomplish more. Finally, when a motor deficit can be corrected by tendon transplants or joint fusions and nerve regeneration has also a pood expectancy of correcting this motor deficit, the evaluation of regeneration must continue until it is established whether these supple- mentary procedures are or are not indicated. The following discussion on evidence for regeneration embodies a concept of examination and evaluation that must be employed at frequent intervals in every nerve injury case until the statement can be made that no further therapeutic measures are required. A knowledge of the final end result in each case is also of importance but has nothing- to do with the concept that hospitalization should be continued only until it is clear that, regardless of possible variations in the end result, further definitive procedures will not be employed. The following discussion therefore applies not just to the initial early examination but to all subsequent examinations that are necessary until the individual is finally sorted into the group that can be labeled as requiring no further definitive therapy. This discussion has been divided into three parts: certain evidence for re- generation, uncertain evidence for regeneration, and certain evidence for failure in regeneration. By satisfactory regeneration is meant regeneration as good as can be accomplish?d by the average suture of this nerve in this location at a certain time period after injury. Such a degree of regeneration may be far from satisfactory in some situations and it may be defined as a level of function which precludes the necessity for further operative pro- cedure. At this point of the discussion it should be stated that electro- physiological evidence as proof of some regeneration is of no interest unless it carries with it a strong predictive value for satisfactory regeneration. The rules which are presented for the interpretation of evidence for re- generation cannot be derived from a study of end results but must be based upon serial data obtained from early cases in the interval when decisions regarding surgical management are made. The unavailability of such pertinent data from late follow-up material was realized and a study of 300 patients with early nerve injuries at Valley Forge Army Hospital was therefore undertaken by the Philadelphia Study Center under Army con- tract in the interval from 1951 to 1954. Further longitudinal data ob- tained from 500 cases during the active hospitalization period at Gushing General Hospital (1944 to 1946) are occasionally brought to bear as well. 5/8

a. Certain Evidence of Regeneration (7) Voluntary motor function. When there is movement against resistance which can only be the result of the voluntary contraction of the first muscle receiving its nerve supply through the nerve lesion, satisfactory regeneration is present. This involves the assumption that spotty recovery is a rarity— that the degree of recovery which develops in the most proximal muscle to receive its nerve supply foreshadows the recovery that will obtain in more distal muscles and in sensory supply to skin. Such a correlation uniformly exists in this follow-up study and it obtains again in the Valley Forge series. The extreme distal muscle will not do nearly as well as proximal ones in the high lesions that involve both proximal and distal groups but this is not of present concern since the distal function predictable with this evidence for proximal recovery is certain to be better than could be achieved by resection and suture. The assumption appears to be correct that at the level of nerve damage the axons supplying proximal muscles are so widely dispersed through the entire cross section of the nerve trunk that the recovery of a reasonable proportion of these dispersed axons as reflected in one muscle's contraction is a proper index of the regenerative capacity of the nerve trunk as a whole. The conclusion that this movement against resistance is truly a reflection of nerve regeneration must be reached with some caution. A clear under- standing is necessary of the substitutive or compensatory movements that can be learned progressively by utilizing unaffected muscles. In addition, there is the possibility, particularly in the case of the median and ulnar nerves, for overlapping or anomalous innervation so that even the definitely established contraction of an easily visualized muscle may not be evidence of recovery in the nerve presumed to supply it. Whether a movement should be properly ascribed to innervation by a particular nerve is a ques- tion which can sometimes not be settled by clinical observation but can easily be decided, as will be discussed below, by observing the motor responses on electrical stimulation of the nerve in question. The statement has been made that movement against resistance is a certain evidence of satisfactory regeneration, but obviously this degree of muscle strength can occur only after there is at first only a visible contraction in the muscle insufficient to move the part, followed by contraction sufficient to cause movement at the joint which then becomes of sufficient strength to lift the part against gravity and finally against resistance. Accordingly, when only a visible contraction of the muscle is evident at a time early enough to be consistent with progressive improvement in that muscle, there is reason to follow its performance for 4 to 6 weeks in the expectation that contraction against resistance will result. If reference to the expected result of suture in cases like this one indicates that this particular muscle could not possibly go so far as to develop contraction against resistance, satisfactory or end- point regeneration would then be assumed. If, on the other hand, good muscle strength is the usual result of suture in the case at hand, the evidence 579

for regeneration is not certain until the strength level of movement against resistance has been reached. Because definite evidence for improvement is such an important criterion in deciding surgical management, the importance of accurate recording that lists not only muscles which are working but grades their strength cannot be overemphasized. Once there is movement against resistance muscle strength can be measured against a simple spring scale and the progressive increase in pounds of strength recorded is of further help in predicting the end result. However, the practical surgical decision usually depends only upon reaching the func- tional level of movement against resistance. (2) Preservation or recovery of sensation. It is unusual to see evidence for skin innervation before voluntary contraction in a proximal muscle has signaled satisfactory regeneration, and this never occurs after suture. However, high velocity missiles appear capable of causing a type of nerve contusion which results in temporary motor dysfunction (axonopraxia) without abolishing sensory perception. This situation of sensory perception in the face of total motor paralysis is seen only in early cases and it is an almost certain indication that motor recovery will begin to occur far short of the long periods necessary for regeneration. The finding of sensory without motor function more than a month after injury calls for more careful examination: either motor recovery actually is present or sensory function is not. Nerve stimulation will produce muscle contraction which the patient has not learned to initiate himself or the sensation perceived is not mediated through the nerve in question. Only sensation in the zone of autonomous supply must be given consideration as previously described. The tips of the index and fifth fingers allow for easy discrimination of autonomous supply in the median and ulnar nerves while the radial nerve has no certain autonomous zone and absence of a clear-cut zone of total sensory loss does not preclude a complete division of the radial nerve. The absence of any area of total loss of peroneal sensation is proof for major continuity but the presence of only a small zone of sensory loss, no matter how limited, can be consistent with interruption. Preservation of sensation in the sole of the foot is proof for a major degree of tibial con- tinuity. The large overlap of saphenous sensation into the instep may be confusing. Even the lowest grade of sensation in a true autonomous zone, such as the perception of discomfort on forceful pinching of the terminal phalanx of the index finger in the case of the median nerve, strongly suggests the possibility of major continuity. Certain evidence is presented when pin- prick to the autonomous zone causes definite pain. More detailed testing of sensation is of importance in evaluating end result and of interest in following a gradual improvement in sensory recovery during active regeneration. However, from the standpoint of a practical surgical decision, information is sought in the early case concerning the existence of some sensation to the autonomous zone while in the late case the progress of motor recovery usually settles the question of adequate 580

recovery before sensory recovery begins. Only in the case of a distal median nerve lesion may the quantitative degree of sensory recovery enter into surgical judgment. (3) The preservation of siveating.—Observations concerning sweating in the autonomous zone of the injured nerve ordinarily parallel sensory findings. Total sensory loss from a peripheral nerve injury is invariably accompanied by total loss of sweating and recovery of sweat function is not discernible even to skin resistance measurements before ordinary testing with a simple pin has revealed that sensation is present. Observations on sweating do have the advantage of being objective and independent of the patient's cooperation. Six patients in the small Valley Forge series have been studied who had convinced their examiners, and possibly themselves, that a major sensory loss existed in hand or foot after a wound of that extremity. The preservation of sweating was certain evidence against a major nerve lesion and was an important step in delineating the problem as one of hysteria or malingering. On two occasions the preservation of sweating in an area of sensory loss established that a root lesion which did not involve autonomic pathways was responsible for the sensory deficit rather than a wound of the extremity which was thought to have damaged a peripheral nerve. (4) Motor response on nerve stimulation. This simple electrical test so fre- quently calls for a revision of the estimate of nerve function deduced from clinical examination that it should be a part of the examination of every case where the adequacy of regeneration is at all in doubt. The type of current utilized to stimulate the nerve trunk is unimportant so long as it is of adequate intensity to cause maximal nerve stimulation and is still easily tolerated by the patient. For stimulation of the underlying nerve trunk through the intact skin, the usual operating room stimulator or the machine in use in the physical therapy department will be adequate, utilizing simple galvanic shock or bursts of alternating or faradic current applied through a moistened unipolar electrode of 1 cm. in diameter. Points where the various nerve trunks are in a location easily accessible to stimulation from the skin surface are illustrated in current monographs. The nerve trunk must be stimulated proximal to the branches innervating those muscles whose contractions will be a measure of innervation through the lesion. It does not matter, except in the first week after injury, whether the point stimulated is proximal or distal to the lesion since any axons conducting the stimulus to the muscle must be intact from muscle to anterior horn cell. The efficacy of the stimulus can be tested on the opposite normal limb in a symmetrical location. It must be realized that response in a muscle close to the point of stimulation can be the result of direct stimula- tion of the muscle rather than nerve conduction. When there is no motor response on nerve stimulation, or the intensity must be raised to a point where neighboring nerves and muscles begin to respond, resort must be made to more direct stimulation of the nerve. This is accomplished by inserting two hypodermic needles at 1-cm. distance into the close proximity of the nerve and applying current to these two needle electrodes to secure 581

a confined bipolar stimulation of the nerve trunk. This has been referred to as a bipolar-intraneural stimulation but the needles need not actually impinge upon the nerve trunk although no harm results when they do. The intensity of stimulus required for maximal stimulation of the nerve trunk through needle electrodes in its close proximity is very small and the make-and-break shock delivered by two l^-volt flashlight batteries is adequate. Intensity can be regulated by a simple rheostat. This simple modified flashlight is a very satisfactory instrument for nerve stimulation or an opthalmoscope with its built-in rheostat can be modified easily to deliver make-and-break shocks graded up to 3 volts. The stimulator used for surface testing is entirely satisfactory if stimulation is begun at a low intensity of current, while the modified flashlight can be used in situations where cumbersome stimulators are not readily available. Surface stimula- tion is preferred to stimulation through needles when it gives the necessary information but it should not be concluded that a nervs is incapable of response to electrical stimulation until an additional test has been made with bipolar needle electrodes. Positive results with beginning recovery are frequently seen on needle stimulation when no response occurred with the surface electrode. This is particularly true in the case of deep-lying nerves like the radial and tibial. If a Tinel sign is present at the segment of nerve that is stimulated, the same kind of paresthesias referred to the sensory area of supply of the nerve should be experienced with each electric stimulus as an indication of adequate stimulation of the nerve. In this situation a failure in motor response is meaningful as not being the result of inadequate stimulus. When motor response does occur the responding muscles should be noted and the strength of movement of the part graded in the same rough quantitative fashion as is followed for the voluntary motor examination. Motor response on nerve stimulation has the same significance for regen- eration as does voluntary contraction. However, voluntary contraction frequently does not become evident for several weeks after the first response of the muscle to nerve stimulation but the patient will ultimately always learn to initiate a voluntary contraction of the same strength that is demon- strated by artificial nerve stimulation. Accordingly, the same certain evi- dence for satisfactory regeneration is afforded by muscle contraction on nerve stimulation as is afforded by voluntary muscle testing but at an earlier date and in a way which rules out the possibility that the observed move- ment is not supplied by the nerve being tested. During the stage of progressive regeneration only a visible contraction in the most proximal muscle is reason to await the development of voluntary contraction against resistance so long as the magnitude of contraction increases with successive examination. In the deep-lying muscle, especially when there is consider- able overlying fat or edema, contractibility can be demonstrated by move- ment of needles inserted in the muscle before movement of the skin or of the part to which the muscle is attached becomes evident. This is a particularly sensitive test of early muscle function. 582

b. Uncertain Evidence (or Regeneration (7) Tinel's sign. When percussion of the nerve trunk distal to the lesion can be performed in such a way that the neuroma itself is not being dis- turbed and gives rise to paresthesias referred to the area of sensory supply to the nerve trunk, positive proof is present of the continuity of sensory axons from the point percussed through the lesion to the central nervous system. When a Tinel sign is present at all in the distal nerve trunk it will invariably progress distally at a fairly rapid rate to indicate that the sensory axons responsible for this phenomenon are traveling at a rate of 3 or 4 millimeters per day or 3 or 4 inches per month. This behavior of the Tinel sign affords clear evidence that some regeneration is going on but it unfor- tunately does not give proof that this will be satisfactory regeneration as this has been defined. More than three-quarters of those nerve lesions which require resection and suture have been associated with a properly advanced Tine! sign. This may be correlated to the finding that grossly an anatomical connection between the nerve ends may be scarcely demonstra- ble while microscopically a handful of unmyelinated fibers in one small area of the distal nerve's cross section appears to have been responsible for the sensitivity of the distal nerve trunk. On the other hand, as will be reem- phasized below, the absence of a Tinel sign, when a month has allowed an opportunity for it to progress at least 3 inches below the lesion, is certain evidence of absent regeneration. (2) Shrinkage of the area of sensory loss. It has already been pointed out that sensory return is of importance only when it occurs in the autonomous zone but it is difficult not to be impressed by a shrinkage area of sensory loss as evidence for improvement in nerve function, especially in distal lesions of the median or tibial nerves where the motor functional deficit may be minimal. Unfortunately, the autonomous zone is the most distal, and sometimes it would be profitable to know whether sensation in a more proximal area, previously anesthetic, signifies regeneration or simply overlap supply from undamaged nerves. When the newly recovered sensation is incorrectly localized by the blinded patient excellent evidence is at hand that this is the result of regeneration while proper localization in a previously insensitive area speaks more for overlap. The question can be settled by discovering whether the sensation drops out on anesthetic block of the injured nerve or of the normal neighboring nerves. Ordinarily this evaluation of the diminishing zone of sensory loss is not the crucial point in determining whether there is evidence for satisfactory regeneration. (3) Improvement in the usefulness of the extremity. It is a rare patient who does not use his injured arm and leg better long before nerve regeneration can make any contribution to function. This is the result of compensatory use of uninvolved muscles which occurs to some degree in every well- motivated patient and to marked degree in those whose muscle attachments or shared innervation is such that so-called trick movements develop. Such natural improvement in the absence of specific regeneration empha- sizes the point that motor testing must be confined to those visible muscles 583

and movements which can only be the result of nerve regeneration, check- ing questionable situations with observation of the responses on nerve stimulation. (4) Electromyography. This is an extremely sensitive method for the unequivocal demonstration of motor innervation as reflected in the demon- stration of motor unit potentials on voluntary effort and of action potentials in response to nerve stimulation. The latter method is more objective and should be resorted to when immediate adjacent small muscles can create potentials on voluntary effort which are actually delivered by uninjured nerves. Because the apparatus involved is expensive and cumbersome and the performance of the test as well as the maintenance of the apparatus require time and considerable technical ability, it is appropriate to see to what extent electromyography adds to the information that is obtained from simple stimulation of nerve with a flashlight battery. One of the major difficulties in evaluating the relative merits of proposed electrodiagnostic tests has been that each enthusiast has reported on the application of only his test. The Valley Forge material provided an excellent opportunity to use the complete battery of electrodiagnostic tests on each patient at the same examination so that the areas of agreement and disagreement could be evaluated. Evidence for regeneration obtained by EMG testing was in good agree- ment with the results of nerve stimulation. There was no case in which visible muscle response on nerve stimulation was not associated with recorded action potentials on nerve stimulation. In 39 cases motor units were not seen on voluntary effort when potentials could be produced by stimulating the nerve and visible movement could be seen as well. Median nerve injuries offered a special problem in that voluntary motor units were frequently seen in attempting to record the opponens pollicis only to find nothing on median nerve stimulation and to realize that potentials on vol- untary effort must be viewed with skepticism in areas of shared innerva- tion. In no case could voluntary motor units be recorded from within the substance of a large muscle without the demonstration of potentials on nerve stimulation. Accordingly, there was a distinct feeling that action potentials on nerve stimulation constituted a more specific indication of regeneration through that nerve than did the recording of voluntary units from an area assumed to be in that nerve supply. The impression also existed that the contribution of electromyography beyond what was learned on simple nerve stimulation involved first the question "How often does nerve stimu- lation result in muscle action potential when it causes no visible muscle response?" and the second question "What is the subsequent course of cases who show EMG but not visible muscle response on nerve stimulation?" In the group of 300 patients tested, only 6 showed muscle action potential at a time when visible contraction could not be perceived on nerve stimula- tion. On 10 occasions actual movement of the muscle was only perceived when needles to be utilized for EMG recording were inserted into the 584

muscle and showed mechanical movement as an indication of definite muscle contraction. Four of these 6 patients had developed visible contrac- tion on nerve stimulation at their next examination which varied from 2 to 4 weeks later. Whether these 4 would have shown these grosser signs of recovery by 2 weeks or even 1 week if retested earlier is an open question. The only other 2 cases which showed EMG evidence of muscle innervation without a grossly visible response on nerve stimulation failed to develop such response or to show increase in EMG potentials in an additional 4- week period. Both cases were operated upon and showed minimal con- tinuity between nerve ends with less than 5 percent of the distal cross section showing myelinated and amyelinated nerve fibers. Electromyography appeared to afford uncertain evidence for regeneration when muscle function could be demonstrated only by this means and did not progress to sufficient innervation to produce grossly visible contraction on nerve stimulation. If the method were used in conjunction with nerve stimulation it would afford, in an occasional case, the sole evidence for recovery that would delay the performance of an unnecessary exploration. Clearly evidence for innervation by this sensitive test alone is insufficient for the prediction of satisfactory regeneration and should call for only 2 or 3 weeks' postponement of surgery if more valid signs of regeneration do not appear. (5) Chronaxie. The determination of chronaxie by direct muscle stimu- lation was carried out on the Valley Forge patients whenever total paralysis existed and was continued to the early stages of recovery of voluntary function. By this experience, such testing appeared to be an excellent method for delineating those muscles whose innervation was impaired. The occasional finding of muscles which could not be made to contract on direct stimulation was useful in establishing that, for these muscles, even a return in innervation would not result in satisfactory function because of the paucity of contractile elements that had been largely replaced by atrophy and fibrosis. Chronaxie determinations were not of any help in anticipating regeneration as the high values indicative of denervation usually did not fall significantly before there was definite clinical evidence for motor recovery. In the occasional patient with a wound of the extremity who exhibits a profound motor weakness on an hysterical basis, the findings of normal chronaxie values are of assistance in establishing that there is not even partial denervation of the muscle by the trauma to the extremity. A complete strength-duration curve might have been of more assistance in exhibiting discontinuities of the curve suggestive of beginning innervation at an early stage where such prediction would be helpful but only the chron- axie point on the curve was established routinely. (6) Galvanic tetanus ratio. This test was not used on all Valley Forge patients because in the earlier work at the Philadelphia Study Center occasional men found the test so uncomfortable that they refused to return to Philadelphia for subsequent examinations. However, during the early stages of enthusiasm for this test, it was used routinely at Gushing Hospital 585

and records were reviewed at Percy Jones Hospital in patients studied before operation was undertaken for resection of neuromas with minimal continuity and suture. It was clearly evident that a satisfactory rise in tetanus ratio above the denervated value of 2.0 was uncertain evidence for satisfactory regeneration. Tetanus ratio changes would appear to be a definite indication for some regeneration through the lesion just as in the case with the progressive Tinel's sign but the test does not differentiate between minimal regeneration and satisfactory regeneration, nor is a failure in rise of tetanus ratio a definite proof for unsatisfactory regeneration. c. Certain Evidence for Unsatisfactory Regeneration The decision that a nerve will never regenerate in as satisfactory a manner as could be achieved by resection of the lesion and suture is more difficult to reach than is the decision for satisfactory regeneration when supported by positive signs of recovery. With no evidence for nerve regeneration at 1 month after injury, including the absence of any Tinel's sign below the lesion, nerve exploration should be indicated even though there is still a reasonable chance that a lesion in continuity will be discovered that calls for no radical treatment at this early time. On the other hand, those cases having a gross nerve disruption benefit sufficiently from such early defini- tive treatment as to justify exploring the entire group. There may not be physiologic evidence to clarify the potentialities for nerve regeneration for 3 to 6 months after injury and prompt exploration is likely to answer the question. Negative exploration at this early date can frequently be pre- vented by nerve stimulation studies giving positive results in patients who appear to have a total paralysis to clinical testing. In a rare case electromy- ography will show evidence for regeneration when there is no visible re- sponse to nerve stimulation and this is ample reason for waiting up to 1 month to determine whether more certain signs for satisfactory regeneration develop. There would seem to be no reason for being conservative about nerve exploration provided conservative treatment of the nerve is main- tained at operation when there is sufficient gross continuity to accommodate regenerating axons. If such is the operative finding, and if either percussion or electrical stimulation of the distal nerve trunk causes paresthesias that establish the presence of axons in continuity through the lesion, resection of the neuroma in continuity is not indicated until sufficient time has passed to clarify from physiologic evidence the potentials for regeneration of this lesion. The problem of the neuroma in continuity whose status cannot be determined by visualization at operation is a frequent one and it is therefore necessary to go to some pains to define certain evidence for unsatisfactory regeneration when this cannot be settled by the gross appearance of the lesion. Such determination of unsatisfactory regeneration depends upon a knowl- edge of the time at which reinnervation to a given muscle has gone as far as it can go, plus the assumption that the degree of reinnervation to a proximal muscle or its absence is a reasonable measure of the degree of reinnervation 586

which will subsequently occur to more distal muscles and to skin. The rate of down-growth would appear to vary for different types of regenerating axons. Those axons which are sensitive on percussion in the progressing Tinel's sign would appear to travel as rapidly as 5 mm. per day or roughly 6 inches per month in some instances. A similar growth rate would appear to obtain for axons which reach muscle and produce a change in electrical reactivity as measured by the galvanic tetanus ratio. Whether it is matura- tion of these same axons which results ultimately in the appearance in the muscle of motor units by electromyography and finally visible contraction, either by nerve stimulation or by voluntary effort, is unknown. At any rate, review of clinical material indicates that visible motor response on nerve stimulation occurs at a time consistent with a fairly uniform growth rate for every nerve, if it is ever going to occur at all. EMG evidence for motor regeneration comes only slightly earlier and is not necessarily followed by this more certain evidence for regeneration. Voluntary motor contrac- tion may begin close to the time when there is a response to nerve stimula- tion or may not develop until weeks later. Accordingly, when voluntary contraction in a given muscle does not begin at the expected time this case should not be referred as one of unsatisfactory regeneration without making a test of nerve stimulation—good motor reinnervation may be present with an inability of the patient to demonstrate it on voluntary effort. First evidence of spontaneous regeneration, or of regeneration following suture, may be plotted for any given nerve against the distance from the lesion to the muscle involved (67). Because of varying intervals between examinations an entirely uniform growth rate may not be suggested by these plots but a definite limit to the interval in which innervation will occur, if it is to occur at all, seems clearly defined. In most conservative terms, re- generation will not occur unless a growth rate of at least 1 inch per month is exhibited. In other words, if the first satisfactory test muscle to be in- nervated below a nerve lesion is x inches from the lesion and does not respond on nerve stimulation after x months, one has certain evidence for unsatisfactory regeneration. Extra time must be allowed when extensive transplantation of a proximal nerve segment makes a level above the suture line the point for beginning down-growth. Average distance from nerve lesion to muscle is illustrated in the tables developed by Seddon (71). Actually measurements can be made in a given patient without reference to tables or even to anatomical charts. With a galvanic stimulator, the motor point for the muscle in question can be determined in the uninjured extremity and marked on the skin. A symmetrical mark can be made on the uninjured side and the distance from neuroma to this point measured directly. When motor response does not occur by the calculated deadline, clear evidence is present for unsatisfactory regeneration whether it be after a suture which seemed satisfactory or whether it has occurred when a benign appearing neuroma in continuity has been left in place. Resection of this neuroma in continuity and suture are now indicated unless there is strong 587

reason to believe that little will be accomplished by suture. In high lesions and in situations where there has been an excessive delay since injury, it is worth while to refer to the motor regeneration tables to determine what is to be expected of the operative procedure. In some situations, little in the way of motor recovery can be expected but suture might still be worth while in an effort to establish some sensation, especially in the case of the median and tibial nerves. In addition, two situations should be emphasized where suture is certain to offer little. If there has been so much muscle damage secondary to ischemia or direct trauma, or so much muscle atrophy from prolonged denervation that no contractile elements respond on direct muscle stimulation, such muscles cannot be given function by attempting to improve their nerve supply. Secondly, if the damage to a nerve trunk has occurred by a closed stretch injury with diffuse damage to a long seg- ment of nerve rather than by the usual focal contusion or laceration, no operative procedure on the nerve will improve its function. D. THE PROBLEM OF THE NEUROMA IN CONTINUITY30 1. Introduction The ideal management of a damaged peripheral nerve would appear to be a simple matter. This would include early surgical exploration of any nerve lesion associated with total paralysis and suture of the nerve when it is found to be disrupted. Such a plan suffices in the usual civilian injury where damage is produced by laceration and nerve paralysis will usually be associated with nerve severance. In the military situation, however, with wounding by high velocity missiles, nerve dysfunction frequently occurs without actual nerve discontinuity, and surgical exposure of such lesions in continuity may give no clue as to the subsequent nerve function to be expected. The surgeon should not resect this lesion when doing nothing, beyond lysis, will result in better recovery than is offered by suture: nor should he settle for lysis when regeneration, to the level offered by suture, will not occur. Follow-up studies of World War II material do not tell us, in the absence of careful histologic study of resected specimens, the frequency with which suture was carried out when spontaneous regeneration would have given better results. Failure to do suture when spontaneous regeneration would result in poorer function can be ascertained from this material by asking two questions: (a) How many cases ultimately requiring suture were originally treated by lysis? and (b) How many cases, in which lysis was performed, did not achieve an end result in regeneration comparable to the average suture result in this location? It would seem that nerve lesions requiring resection and suture seldom failed to receive such treatment, but that apparently favorable appearing lesions frequently caused a long delay before reexploration and definitive suture were undertaken. At the same 30 This section is based on the Valley Forge scries studied by Dr. Frank E. Nulsen, Dr. William J. Erdman, II, and Dr. Harry W. Slade. 588

time, data are not available to indicate the frequency of improper resection of favorably regenerating lesions in continuity. The more recent experience in the study of Korean casualties at Valley Forge Army Hospital from 1951 to 1953 affords more specific information concerning this problem of the neuroma in continuity. Among the cases studied, sutures were performed on 126. In 19 of these latter cases the surgeon found his decision difficult because of a high degree of gross con- tinuity. Nine of these examples (cases 2 through 10) are presented below, beginning with those showing the greatest degree of neurotization in the distal segment by histologic study. Case 1 is presented as a lesion whose unfavorable status, as suggested by gross appearance, was not contradicted by histologic study, but by subsequent physiologic evidence, since resection and suture were impossible. The case method of presentation has been selected to reiterate the following rules of procedure. 1. In the absence of gross discontinuity* it may be impossible to judge the regenera- tive capacity of a nerve lesion from its appearance and consistency. 2. If resection of a lesion consistent with better recovery than is possible by suture is to be avoided, certain indicated sutures must be deferred until time has provided criteria for unsatisfactory regeneration. 3. Such delays will not be excessive if it is remembered that operation was not necessarily definitive and the waiting period, defined by time of injury and distance from lesion to first muscle, is not exceeded. Even the lesion which appeared favor- able at surgery must be resected when the criteria for satisfactory regeneration arc not fulfilled on schedule. 4. Early exploration of all nerve lesions associated with major dysfunction is still the best expedient, since the majority of indicated sutures are associated with a finding of gross discontinuity. A policy of awaiting physiologic clarification would have the advantage of avoiding exploration of nerves not requiring suture but would have the far greater disadvantage of delaying the many sutures that can be instituted on the finding of gross discontinuity at early operation. 2. Illustrative Cases Case 1. This patient sustained a penetrating shell fragment wound just below the right gluteal fold in August 1950. Se\en months after injury there was a total motor and sensory paralysis of the sciatic nerve with a suggestion of a Tinel's sign extending to the popliteal space. Nerve stim- ulation of the sciatic nerve with needle electrodes caused neither visible motor response nor action potentials on recording from the gastrocnemius and the peroneus longus. With the long distance to grow from this high sciatic lesion, this negative physiologic evidence did not necessarily classi- fy the lesion as an unfavorable one but exploration was undertaken on the possibility that a major disruption would be discovered. At exploration 7 months after injury, the sciatic nerve was found to be involved, over a 14-cm. distance, in dense scarring with 3 separate fusiform enlargements which were stony hard to palpation. (See plate 38.) The surgeon believed the gross appearance of the lesions was so unsatisfactory as to warrant resection and suture on this evidence alone. He settled for a neurolysis only because approximation of the nerve ends for suture would have been impossible if the entire area of involvement had been resected. 589

H Plate 38. Operative photograph showing three separate fusiform enlargements over a 14-em. distance on the sciatic nerve (case 7). Hemostat in middle of photo- graph points to the middle lesion. Contrary to the poor prognosis given by the surgeon, plantar flexion of the foot was noted 10 months after injury and dorsiflexion of the foot began at 12 months. Final examination of the patient 17 months after injury revealed 80 percent strength in plantar flexion and 50 percent strength in inversion of the foot. The peroneal muscles were able to evert the foot against gravity but not against resistance while dorsiflexion of the foot could be done against 4 pounds resistance. There were barely perceptible toe flexion and absent toe extension. The patient could walk satisfactorily without a brace, exhibiting no tendency toward foot-drop during ambu- lation. Forty gm. pain stimulus could be felt throughout the foot and lateral aspect of the leg. Comment. It was entirely fortuitous that these lesions in continuity, which were consistent with a degree of regeneration far exceeding what could be achieved by the best sciatic suture at the level of the buttock, were not resected. The gross appearance seemed inconsistent with recovery and only the technical impossibility of suture resulted in conservative manage- ment. This case example points out that when the gross appearance sug- gests that reasonable regeneration is conceivably possible, there being no obvious discontinuity, a decision for resection should be delayed until physiologic evidence can clarify the picture. One would here have waited 12 months with 12 inches to grow to the most proximal muscle, the gas- trocnemius. Actually the first evidence of recovery in this muscle occurred 590

at 10 months and even with this long interval for first evidence of regenera- tion, the end result was well above the average seen after sciatic nerve suture. Case 2. This soldier sustained on April 19,1951, a shell fragment wound in the left upper arm with involvement of the ulnar nerve at a point 5 inches above the elbow. At 2 months after injury, a neuroma could be palpated at the site of injury and its manipulation caused tingling in the fourth and fifth fingers. There was no definite Tinel's sign belovv the lesion. Sensation was disturbed in the ulnar sensory area but the ulnar autonomous zone perceived 10-gm. pain and 4-gm. touch stimuli with good localization. The ulnar foreann mus- cles (flexor carpi ulnaris and long flexors to fourth and fifth fingers) showed 30 percent strength. Ulnar intrinsic muscles, such as the abductor digiti quinti and first dorsal interosseous, showed visible contraction insufficient to move the fingers. Electrical stimulation of the ulnar nerve produced muscle contraction of the same magnitude. Most important of all, from a func- tional standpoint, was the patient's ability to open his fingers to their full extent without the disabling fourth and fifth finger clawing that character- izes most ulnar injuries. • At 2]i months the ulnar nerve was explored because of its palpable in- volvement in a large and moderately painful neuroma. Neurolysis and transplantation of the nerve were planned. Operation revealed a firm neuroma 3 cm. in length and 2% cm. in diameter (plate 39). Electrical stimulation of the distal nerve trunk produced ulnar paresthesias and excel- lent motor response in the flexors of the fourth and fifth fingers and the flexor carpi ulnaris. Nevertheless, the gross appearance of the nerve seemed inconsistent with good regeneration so that all of the involved nerve was resected to normal ends. The distal segment was transplanted anteriorly to shorten its course, and the nerve sheaths were approximated with fine tantalum sutures. Microscopically the center of the lesion in cross section (plate 40) shows an abundance of thickened collagenous material with disruption of some but not all nerve fascicles. However, widely separated myelinated fibers can be distinguished (plate 41). Comparison of proximal and distal cross sections reveals a surprising degree of continuity (plates 42-43). Actually, 50 percent of the myelineated fibers present proximally have passed through the lesion into the distal trunk, as seen in high power (plate 44). These are mature axons and their presence in the distal trunk at 2}j months after injury cannot be the result of regeneration; these are axons so mildly dam- aged that distal degeneration did not occur. Partial motor and sensory function had become manifest in muscles and skin 20 inches distal to the lesion very early after injury. In addition, a generous supply of amye- linated fibers in all three sections indicates the beginning of a rich regenera- tive process which would have made an additional contribution to function. The extent of distal neurotization was estimated at 70 percent. 591

Plate 39. Operative photograph (case 2) showing the grossly scarred and thickened neutoma in continuity. Lines b, c, and d indicate the regions from which subse- quent figures were prepared. Following suture this patient ultimately showed the incomplete regenera- tion which appears to characterize all ulnar sutures performed at a level above the elbow. The forearm muscles began contracting 5 months after operation and reached a strength of 30 percent which is quite adequate for useful grip. But the intrinsic hand muscles, which began recovering on schedule at 9 months, never developed more than 5 percent strength. Sensory recovery was good (10-gm. pain and 4-gm. touch thresholds) but there remained striking mislocalization. Although innervation occurred in all ulnar intrinsic muscles, it was no longer sorted out so as to produce the coordination of interosseous -and lumbrical function required for the full opening of the fourth and fifth fingers necessary for grasping large objects, a function which was present preoperatively despite minimal motor innervation. Comment. These are the expected limitations of ulnar nerve regeneration from a high level. Actually regeneration was far better than average for a suture in this location, yet this patient had a better functioning hand before operation and before spontaneous recovery had reached its peak. The gross appearance of the nerve lesion caused the surgeon to choose the known result of suture to the unknown result of spontaneous regeneration. 592

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In this case, however, those axons which were spared had already estab- lished better practical function of the hand than could be yielded by suture. The ulnar nerve is somewhat unique in that weak but coordinated intrinsic muscle function resulting from axon preservation is better than strong un- coordinated function resulting from axon regeneration. A tender neuroma which can be transplanted to a protected location is not in itself an indica- tion for resection and its appearance can be deceiving in terms of the neu- ronal continuity and regeneration which actually exist. The satisfactory result of suture did not produce a functional end result comparable to the result here possible by preserving the lesion in continuity. Case 3. In February 1951 a gunshot wound above the head of the fibula resulted in a total peroneal nerve paralysis. At 3 months after injury a palpable thickening could be felt in the peroneal nerve approximately 4 inches from its first motor branch to the peroneus longus. The only evi- dence for regeneration consisted in a Tinel's sign distal to the lesion, there being no sensory or motor function. EMG recording from the peroneus longus during nerve stimulation and voluntary effort showed no action potentials. Although the interval since injury was short, operation was advised. Four months after injury operation revealed a definite thickening in the peroneal nerve trunk extending over a distance of 2 cm. When again no motor response, and only slight sensory response, occurred on direct stimu- lation of the distal trunk, it was elected to resect 2 cm. of nerve with sub- sequent suture. Gross appearance is shown in plate 45. The proximal cross section shows a high proportion of amyeli.iated fibers to suggest that damage has actually extended well above the proximal face of the section despite the normal gross appearance of the proximal nerve trunk. Distally there is the impression that fully 60 percent of the neurons have regenerated through the lesion as amyelinated fibers. This histologic picture might well have been correlated with adequate regeneration if a longer test of time had been allowed for physiologic evidence of innervation. This patient was followed up to 14 months after operation. By 4 months he had developed a flicker of voluntary contraction in his peroneus longus but at 14 months both peroneus longus and tibialis anticus contracted just sufficiently to evert and to dorsiflex the foot against gravity, not against resistance. The action potentials on nerve stimulation amounted to only 3 percent of normal. This patient ultimately attained sufficient dorsiflexion to discard his brace but his result was below average for peroneal sutures near the knee. Comment. Three months was an insufficient interval after injury for a test of the potentialities of spontaneous regeneration through this lesion. It was proper to explore the lesion with a high probability that a situation of minimal gross continuity would be found so as to call for early suture without further weeks of waiting for physiologic clarification. But with the finding of a gross lesion that could be consistent with regeneration it is mandatory to await the deadline for physiologic evidence of recovery. In 598

Plate 45. Operative photograph showing hemostat pointing to a thickening of the peroneal nerve over a distance of 2 cm. (case 3). this particular situation an additional 2 months' waiting would have been indicated. Case 4. A wound to the left forearm, four inches below the elbow, was incurred in February 1951 with paralysis of the ulnar nerve. Three months later it was seen that the ulnar forearm muscles were functioning well with the presumption that the nerve trunk was damaged at a point below their branches. No type of sensation could be perceived in the ulnar autono- mous sensory zone and no motor function was elicited from ulnar intrinsic muscles on voluntary effort or on nerve stimulation. No motor units were seen on EMG recording from the abductor digiti quinti. There was a Tinel's sign progressing to the wrist. With 8 inches to grow to the first signal muscle, the abductor digiti quinti, it was believed another 3 to 4 months might be required to clarify the status of the lesion on physiologic grounds since the Tinel's sign could occur with only minimal continuity. Exploration of the lesion was therefore undertaken. At 3% months after injury, exploration of the ulnar nerve in the upper forearm revealed a lesion in continuity. The nerve was firm over a 3-cm. distance and showed a fusiform enlargement in the midpoint of this involved segment measuring roughly twice the diameter of the normal segments on either side. Stimulation of the distal trunk caused the patient to experience ulnar paresthesias but there was no motor response. Because the lesion was so firm as to suggest dense scarring internally, resection was carried 599

out and the 3-cm. gap was made up by transplantation anterior to the elbow. Microscopically the proximal cross section showed minimal connective tissue between the nerve fascicles and 80 percent of the axons showed myelinization. A cross section through the center of the fusiform enlarge- ment suggested that at least 60 percent of the area was occupied by scar tissue while only a small proportion of the axons so diffused by this fibrous proliferation showed recognizable myelin sheaths. However, in the distal cross section (plates 46-47), one sees again very little connective tissue with axons numbering at least 50 percent of the amount observed proximally. while over half of these axons showed early myelinization. Here then is another example of a marked degree of interval scarring which, although diffused through the entire cross section of the nerve segment, has failed to prevent a high degree of regeneration into the distal segment. Nine months postoperatively, with 8 inches to grow to the abductor digiti quinti, there was a barely visible contraction in this muscle on voluntary effort and a definite contraction was seen on nerve stimulation. A pain stimulus of 40 gm. could be felt in the ulnar autonomous zone. Fortunately, this patient had not developed the usual clawing of the fifth finger and showed already a relatively useful hand from a gross mechanical standpoint so that he was discharged with the anticipation that further ulnar motor and sensory function could be expected. Comment. Here the surgeon resected a neuroma in continuity at 3 months after injury when the lesion was situated too far from the first signal muscle to allow a physiologic appraisal of potential for regeneration. The micro- scopic studies indicated that a regenerative process was under way which would have exceeded the best results achievable by suture. Resection should have been postponed until physiologic signs could clarify the degree of spontaneous regeneration, 2 to 3 additional months in this case. It is also worthy of note that electromyography did not assist in predicting the high degree of spontaneous regeneration which was taking place according to microscopic evidence. Case 5. On October 16, 1950, a shell fragment produced a mixed laceration and crushing injury of the left forearm centered at a point 4 inches above the wrist. The left ulna bone was fractured, there was direct involvement of flexor muscles and tendons, and an immediate total ulnar nerve paralysis occurred. At 9 months after injury, there were visible voluntary contractions in such ulnar intrinsic muscles as the abductor digiti quinti and the first dorsal interosseous; these were barely sufficient to cause abduction of these fingers. Nerve stimulation caused slightly stronger contractions than observed on voluntary effort. There was rigid clawing of the fourth and fifth fingers and fixation of joints which could be attributed to the combination of ulnar intrinsic muscle loss, direct soft tissue damage in the forearm to the flexor muscles, and a long period of splinting after resurfacing of the forearm by plastic procedures. From a sensory stand- 600

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point, 4 gm. pain and 1 gm. touch stimuli were perceived throughout the ulnar sensory area. In summary, with sufficient time elapsed to approach an end point in spontaneous regeneration, this lesion had permitted con- siderably better sensory recovery and slightly worse motor recovery than could be expected from a suture at this level. The marked clawing of the hand would not have been overcome by further motor recovery since there was a mechanical limitation imposed by flexor contractures and stiff joints. Operative exploration was nevertheless carried out shortly thereafter with disclosure of a lesion in continuity extending over a 3-cm. distance. (See plate 48.) Because this lesion was stony hard and irregular in appear- ance, it was excised over this 3-cm. length with end-to-end approximation of the nerve ends. The microscopic sections (plates 49 through 51) show a reasonably rich regeneration of amyelinated fibers into the distal end to suggest that roughly 40 percent of the proximal axons have regenerated past the lesion. At the same time a limited degree of myelinization is seen to be going on distally. This degree of microscopic continuity can be correlated with a functional end result, after 9 months' spontaneous regeneration, which is close to the level of function expected after a suture at this level if it is recalled that motor function would be limited by joint and tendon changes. It is also of interest that this extensive crushing type of injury had dam- aged the proximal nerve beyond the limits of resection of grossly abnormal tissue with the result that the proximal face of the suture gave the appear- ance of being downstream from an area of considerable damage. By 6 months after suture, with some 5 inches to grow to the abductor digiti quinti, the patient still exhibited no voluntary action in this muscle but showed a definite contraction on ulnar nerve stimulation. Forty gm. pain stimulus could be felt in the ulnar autonomous zone. By 9 months after operation, at a time close to the end point of expected improvement from regeneration, there was approximately the same degree of weak action in the abductor digiti quinti and first dorsal interosseous as obtained preoperatively. Sensory thresholds had dropped to 20-gm. pain and 6-gm. touch with striking mislocalization. Tendon lengthening, capsulotomies at the joints, and sublimis transfers to the fourth and fifth lumbrical canals were being considered to correct the marked clawing of the fourth and fifth fingers. Comment. Resection of the neuroma in continuity with suture yielded about the same amount of motor and sensory function that had been ob- tained by spontaneous regeneration. With satisfactory sensation initially, it would have seemed preferable to attempt improvement of mechanical function of the hand by orthopedic substitutive procedures since the limi- tations in movement were not to be altered by even a marked improve- ment in the motor function of the ulnar intrinsic muscles. With the long lapse of time since injury, the motor and sensory function of this neuroma in continuity was a much better indication of the regenerative process as 603

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confirmed by histologic study than was the gross appearance of the lesion at operation. This particular histologic picture gives a roughly quanti- tative idea of that degree of anatomic regeneration which is correlated with a physiologic result that is achieved by the average suture in this location. Case 6. This patient sustained a shell fragment wound at the right axilla on October 10, 1950, with immediate paralysis of the median nerve. Six weeks later he showed a definite voluntary contraction of the flexor carpi radialis without motor function distal to this point. There was no evidence of median sensory recovery. There was a Tinel's sign down to the elbow. At this short interval after injury, this appeared to be good evidence for satisfactory regeneration. However, at 8 months after injury, with 10 inches to grow to the median forearm muscles, there had developed only 25 percent function in the flexor carpi radialis and a trace of voluntary movement in the flexor indicis proprius. Stimulation of the median nerve resulted in only this same amount of motor response as was observed on voluntary effort with no action in the long flexor to the thumb or the in- trinsic muscles of the hand. Tinel's sign had extended to the wrist and a pain stimulus of 40 gm. could be felt throughout the median autonomous zone. It was considered that this level of regeneration after 8 months was unsatisfactory and exploration should be carried out. The median nerve was exposed in the axilla 8 months after injury and there was disclosed a fusiform neuroma in continuity, 2.9 cm. in length, with a rather firm consistency (plate 52). At its thickest point this lesion was roughly two times the diameter of the slightly shrunken distal trunk. Stimulation produced the same degree of limited motor response observed in preoperative testing. The involved area was resected and the nerve ends were approximated. On microscopic examination the proximal cross section showed a mini- mum of connective tissue with roughly equal proportions of myelinated and amyelinated axons. The distal end showed that roughly 40 percent of these axons had traversed the scar and one-fifth of these showed myelini- zation. By 6 months after suture there was again a flicker of voluntary action and some response to nerve stimulation in the flexor carpi radialis. Be- cause it seemed unlikely that there would ever be any recovery of median intrinsic muscles, a tendon transfer was done to supply opposition of the thumb, utilizing the flexor carpi ulnaris. By 10 months after operation there was a 15 percent contraction in the flexor carpi radialis with no func- tion in the thumb or index long flexors by voluntary effort or on nerve stimulation. Deep pressure could be felt as pain in the tips of the index and middle fingers but a 40-gm. pain stimulus could still not be perceived. The patient had excellent opposition of the thumb by virtue of this tendon transfer and was able to pick up small objects between thumb and middle finger with visual aid. He was limited chiefly by his median sensory deficit 608

and was discouraged at this time since no further therapy was indicated regardless of the degree of subsequent recovery attained. Comment. Although this man at 8 months after injury seemed destined for an unsatisfactory degree of spontaneous recovery, microscopic study of the resected lesion revealed a level of regeneration which, when seen in distal lesions of long standing, had been consistent with as much function as could be obtained with suture. In other words, with involvement of the median nerve at an unfavorable level high in the axilla, this patient was presumably on the way to better functional recovery than could be offered by suture at this location. He was not followed to an end point in his regeneration from suture but did show less nerve function 10 months after suture than he had exhibited by virtue of spontaneous recovery 8 months after injury. In retrospect, it seems clear that his relatively low grade median recovery Plate 52. Operative photograph illustrating I he fusiform neuroma in continuity 2.9 cm. in length (case 6). 408080—47- -41 609

should have been accepted as the best possible in the face of a high lesion. Motor deficits should have been corrected by tendon transfers when he was showing good sensory recovery. An attack on the nerve not only failed to improve motor deficits, for which there were alternative means of correction, but undoubtedly resulted in a lesser degree of final sensory recovery. Again this gross appearance of a bull>ous neuroma in con- tinuity is in contrast to the microscopic and physiologic evidence for a degree of regeneration certainly as good as could be achieved by suture. Case 7. This soldier sustained a bullet wound to the lower left forearm in January 1951. Three months later there was a complete ulnar motor and sensory deficit. However, on EMG recording from the abductor digiti quinti there was a definite action potential in response to ulnar nerve stimu- lation. In addition, a Tinel's sign extended to the wrist. Clearly there was some continuity through the lesion but since, with 5 inches to grow, an additional 2 months might be required to clarify the adequacy of regeneration by abductor digiti quinti function, surgical ex- ploration was advised with consideration of resection and suture only if there were gross discontinuity. At operation 4 months after injury a bulbous neuroma in continuity was discovered. Stimulation below the lesion resulted in ulnar paresthesias but, as expected, did not yield motor response. Because of the poor gross appear- ance of the nerve, resection was done and suture was accomplished after ulnar nerve transplantation at the elbow permitted approximation of the ends. Microscopically the proximal and distal sections show little scarring with at least 40 percent continuity of axons although the proportion of mye- linated axons has dropped from 70 percent to 10 percent. These findings suggest that satisfactory regeneration, or regeneration comparable to an average suture result, would have occurred spontaneously. Actually this man maintained a useful hand with no clawing, despite his ulnar deficit and was discharged 9 months postoperatively, with good ulnar sensation (10-gm. pain and 4-gm. touch) and 50 percent strength in his abductor digiti quinti and first dorsal interosseous, a better than average suture result. Comment. This man had a good result from ulnar nerve suture, yet the microscopic studies suggest he would have done as well if left alone. This example illustrates again the difficulty of deciding on the basis of gross appearance alone, when it is too soon for conclusive physiologic evidence, whether a lesion in continuity should be resected. Case 8. This patient sustained a shell fragment wound 3 inches above the left elbow in August 1950 with a resulting ulnar nerve paralysis. The nerve was explored 4 months later and a firm, fusiform lesion in continuity was discovered. Because the gross appearance of the lesion was not clearly inconsistent with regeneration, with a short interval since injury, only a neurolysis was done at this time. At a time 8 months after injury, 4 months after lysis, the only evidence for regeneration was a Tinel's sign to the wrist. 610

There was no sensation in the ulnar autonomous zone. Although it was the clinical impression that there was slight activity in the ulnar forearm muscles, no visible response occurred on nerve stimulation nor was there activity in those muscles on EMG recording. Reoperation and suture were advised, but the surgeon who had visualized the original lesion in continuity preferred to give it a further test of time; reexamination at 10 months after injury showed an unchanged picture except that a flicker occurred in the flexor carpi ulnaris on nerve stimulation, a degree of motor function far below that consistent with adequate recovery after so long a time interval. A second exploration was done in August 1951, 12 months after injury. Once again the lesion appeared benign and the surgeon was loath to resect it, especially when stimulation produced a slight flexor carpi ulnaris con- traction. This patient was again evaluated in March 1952, some 19 months after injury, with physiologic evidence having suggested since 6 months after injury that regeneration would be poor. From a motor standpoint he now showed a barely visible flicker of motor activity in the flexor carpi ulnaris on voluntary attempt and on nerve stimulation, while deep flexors to the fourth and fifth fingers were able to move the distal finger tips against % pound resistance, less than 2 percent normal strength. There was no voluntary function in the intrinsic hand muscles but on stimulation there was a visible flicker in the abductor digiti quinti and an action potential in this muscle in response to stimulation which was considered of normal amplitude. From a sensory standpoint, deep pressure could now be felt at the tip of the fifth finger as a diffuse painful sensation and pain stimula- tion of 40 gm. was perceived one time in four with mislocalization. Actually this patient had a useful hand from the standpoint of gross grasping function and had suffered minimal clawing. There seemed little point in trying to improve nerve function at this late date but he had developed marked tenderness over his neuroma above the elbow. This was considered an indication for operative resection in a situation where little could be lost in terms of nerve function. A third exploration was therefore carried out at 20 months after injury and the fusiform neuroma was resected after stimula- lation had given motor response identical to that described in the testing just previous. The specimen measured 4.4 cm. in length and showed a fusiform enlarge- ment at its center. Microphotographs are shown in plates 53 through 56. The proximal face of this specimen shows equal proportions of myelinated and amyelinated fibers with minimal scarring. The center of the neuroma shows an abrupt decrease in the proportion of myelinated fibers with striking separation of the nerve elements by connective tissue. The distal segment shows 25 percent of the number of neurons seen in the proximal section and about 10 percent of these suggest myelinization. The presence of distal myelinated fibers and the occurrence of even slight motor function on nerve stimulation would constitute a favorable sign for adequate regeneration in the early lesion. However, in this 12-month old lesion 611

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there is an excellent correlation between both anatomic and physiologic evidence for inadequate regeneration. This patient was discharged 6 weeks after surgery since he had a relatively useful hand despite his total ulnar deficit and further treatment would not be contemplated regardless of the degree of regeneration he achieved from suture. Comment. The gross appearance of this lesion in continuity was so favor- able that even at 12 months the physiologic evidence for inadequate regeneration was cast aside by the operating surgeon. Adequate regenera- tion will occur within the limits of a definite time schedule if it is to occur at all. When there is minimal function in a muscle within 6 inches of a lesion at an interval 8 months after injury, further waiting, to 20 months in this case, will not see any practical increment in this function. This first failure in proximal recovery at the same time predicts a similar limita- tion in subsequent distal motor and sensory recovery. The surgeon was correct in awaiting further developments when he visualized a favorable appearing lesion 4 months after injury. The functional recovery to be expected became defined as inadequate by 6 months after injury when there was nothing to lose and the possibility of a large gain by radical resection and suture. Histologic studies demonstrate the striking dis- crepancy between the favorable external appearance and the unfavorable internal configuration of this lesion and define a level of regeneration as observed histologically which can be correlated with inadequate physiologic recovery after 20 months of elapsed time. Case 9. This patient's left ulnar nerve was injured on September 16, 1950, by shell fragments at a level of 5 inches above the elbow. An asso- ciated fracture postponed consideration of the nerve lesion until 8 months after injury. At this time a Tinel's sign extended over a distance of 8 inches below the elbow and it was the clinical impression that there was slight active move- ment in the deep flexors to the fourth and fifth fingers. There was no sen- sory recovery in the ulnar autonomous zone. Stimulation of the ulnar nerve above the elbow failed to cause any visible movement in the forearm muscles but a few action potentials could be seen by EMG. There was no evidence for neurotization in the intrinsic hand muscles. It was concluded that since sufficient time had elapsed for satisfactory regeneration of the forearm muscles and this had not occurred, suture of the ulnar nerve should be undertaken even if a lesion in continuity were discovered. At operation, 9 months after injury, the lesion was found to consist of a bulbous proximal end in perhaps 50 percent gross continuity with a mildly shrunken distal nerve end. Some 6 cm. were resected and a satisfactory suture accom- plished. Histologic study (plates 57 through 59) shows an apparently healtyh appearing proximal end containing a high proportion of myelinated fibers while in the distal end myelinization is scant and it is estimated that only 20 percent of the proximal neurons have continuity with distal amyelinated 616

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fibers. This degree of histologic regeneration is to be correlated with phys- iologic evidence for regeneration far below the level to be achieved by the average suture. Eight months following suture there was over 50 percent strength in the ulnar forearm flexors while insufficient time had elapsed for any physiologic evidence of recovery to the intrinsic hand muscles. The earliest signs of sensory recovery were present in the ulnar autonomous zone in that deep pressure to the tip of the fifth finger could be clearly perceived as a spread- ing painful sensation. The patient already had a fairly useful hand from a functional standpoint with only minimal clawing of the fourth and fifth fingers. Comment. The gross appearance of this lesion with partial discontinuity posed no problem to the surgeon concerning the indication for resection. It is only regrettable that a complicating fracture unnecessarily prevented the early resection and suture which were indicated. This case is included as an example of a degree of regeneration, as observed histologically, which is consistent with EMG activity and progressing Tinel's sign but not with a useful motor recovery where the test of time was sufficient. Case 10. A wound to the left forearm, 4 inches above the wrist, was sus- tained in September 1951. This resulted in a complete loss of median sen- sation but the patient was not seriously considered for operation until 10 months had passed because excellent function of the thumb suggested some median nerve continuity. At 10 months after injury, the patient was able to oppose his thumb to each of his fingertips and to abduct this thumb at a right angle to the palm to the extent that 3 experienced observers concluded there must be some function of both the opponens pollicis and abductor pollicis brevis. However, because a total median sensory loss persisted with absence of any Tinel's sign below the wrist lesion, these motor pheno- mena were questioned. Stimulation of the median nerve at the wrist both percutaneously and on insertion of needle electrodes, failed to produce any movement in the thenar muscles or any action on EMG recording. Stimu- lation of the ulnar nerve caused a contraction of all the musculature in the thenar eminence which was considered to be composed of a remarkably hypertrophied flexor pollicis brevis. Incidentally, EMG recording on voluntary effort from what was assumed to be the abductor pollicis brevis gave normal-appearing motor units. This suggests that voluntary EMG studies are not of assistance in a situation of this sort when recording from the flexor pollicis brevis could not be avoided. Median nerve suture seemed indicated because of the sensory deficit and because it was first established by infiltration of the median with procaine that the excellent mechanical function of the thumb was in no way affected. At operation a 3.5 cm. neuroma in continuity was disclosed (plate 60) which showed irregular lateral enlargements. One portion of this lesion was fairly soft in appearance and the surgeon estimated from gross findings that 30 percent of the nerve was probably intact. However, because of the lack of evidence of regeneration after 10 months and because stimulation 620

below the lesion failed to give any motor or sensory response, resection and suture were carried out in a situation where the gross findings by themselves would have suggested conservative management. Microscopic studies showed an excellent proximal end with little scar and myelinization of 40 percent of the axons. At the center of the neuroma and in the distal end not a single axon could be detected. Such findings could be anticipated from the physiologic evidence but certainly were not sug- gested by the gross appearance of the specimen. At 4% months after suture the mechanical function of the thumb remained excellent as before and there was already perception in the tips of the middle and index fingers of 10 gm. pain stimulus and 20 gm. touch, while for the first time sweating could be detected in these areas by skin resistance studies. This is a rather remarkable example of evidence of sensory recovery follow- ing late suture. Comment. The presence of trick or compensatory movements of the thumb, probably due to anomalous innervation, prevented recognition of the complete median deficit in this patient until a failure in sensory recovery finally called for his careful evaluation at 10 months after injury. From a pathological standpoint, this is an example of a neuroma in continuity whose gross appearance, both to the surgeon and to the pathologist in the laboratory, suggested a major degree of axonal continuity, quite dis- proved by histologic study of the lesion and the distal nerve segment. Plate 60. Operative photograph showing irregular lateral enlargements extending over a distance of 3.5 cm. (case 10). 621

3. Discussion Ten cases of neuroma in continuity have been presented to emphasize, first of all, the marked discrepancy between the experienced surgeon's classification of the lesion according to gross appearance and consistency* and the actual regenerative capacity of the lesion as established by either anatomic or physiologic evidence. Four lesions, cases 1 through 4, con- sidered unfavorable to surgical exploration, clearly were consistent with better recovery than was possible by suture. Three lesions, cases 4 through 7, were resected because of an unfavorable gross appearance when the spontaneous regenerative process was presumably comparable to that which is achieved by suture. Because of their favorable appearance, the last 3 lesions, cases 8 through 10, would not have been resected but for unfavorable physiologic evidence after long time intervals since injury. Here histo- logic study demonstrated minimal regeneration through nerve specimens whose gross appearance suggested minimal damage even to the pathologist. It should be stressed that the status of a nerve lesion is usually clarified by surgical exploration and that the vast majority of lesions that will not permit satisfactory regeneration are associated with an unequivocal degree of gross discontinuity. Yet, when the gross appearance is conceivably con- sistent with major continuity, no amount of fusiform enlargement or firm- ness to palpation should of themselves constitute indications for resection and suture If, with possible major continuity, the conscious patient does not experience nerve paresthesias on stimulation of the distal segment, resection is indicated. If, with x inches to the first muscle, more than the same x months have elapsed since injury, a failure in motor response on nerve stimulation is an indication for resection. But with major continuity suggested by gross appearance, positive sensory response, and no motor response in the early case, a final decision as to definitive management must await subsequent physiologic events, especially in situations where average suture results are characterized by limited functional recovery. Such situ- ations, where strong conservatism seems indicated, include all high lesions with the possible exception of the radial, and even the lower median and radial nerve lesions. Spontaneous median sensory recovery of low grade is superior to good recovery of median sensation after suture with poor ability to localize stimuli in the working portion of the hand. Spontaneous ulnar motor recovery with weak intrinsic muscles whose action is coordi- nated to permit opening of fourth and fifth fingers is preferable to stronger uncoordinated intrinsic muscle action after suture with persistent fourth and fifth finger clawing. It must be pointed out that the combination of findings calling for con- servatism occurs rarely, despite the seven examples shown, and that an early look at the lesion associated with major dysfunction is still the best policy for accomplishing the vast majority of indicated sutures at an early interval after injury. It must be emphasized also that regardless of previous explorations or present favorable appearance of the lesions, cases 8* 9, and 10, the failure of development of satisfactory evidence for regeneration, at 622

the scheduled time for its appearance, calls for prompt resection and suture unless the lesion is so proximal that suture has little to offer. The explored case is not settled as regards the possible need for suture until such evidence appears. In patients such as cases 8 and 9, with evidence for some regenera- tion, the tendency is strong to wait indefinitely for further improvement, but investigation of over 200 cases, where serial data are available, indi- cates further improvement does not occur beyond the scheduled time; the stream of neurotization does not receive late increments from above. Certain assumptions have been made in classifying the 10 cases presented. The 40 percent neurotization seen in cases 5 and 6 were associated with a degree of function comparable to that achieved by suture; the 70 per- cent seen in case 2 with function in excess of suture result; while the 20 to 25 percent seen in cases 8 and 9 with function far below a suture result. With this much evidence for correlation between histologic and physiologic findings in late cases, it has seemed proper to believe that neurotization of less than 25 percent will not result in function comparable to the result of suture, that neurotization of 50 percent or more will result in function exceeding the result of suture. It is on this basis that those cases in which resection was done before the time for physiologic clarification are classi- fied as improperly resected, cases 3 and 4, and probably not improved by resection, case 7. By the very limitations of therapy, no case is available in which a functioning suture was resected to determine directly that degree of neurotization, by histologic evidence, which corresponds to an average suture result. Histologic study of the central or most scarred portion of those lesions having a high degree of distal neurotization, cases 1 through 4, shows a scattering of axons by interspersed connective tissue that would seem inconsistent with the findings in the distal segment. The surgeon's impres- sion of dense internal scarring is certainly confirmed and one can question whether this scarring process would not finally result in a reduction of distal neurotization. However, such a concept runs contrary to clinical experience. In this experience, function regained through a traumatic lesion in continuity has never shown a late decrement, if the appraisal be confined to objective tests of muscle and skin innervation which are inde- pendent of the will of the patient to use the extremity, of stiffening joints and the like. Exceptions to this rule would appear to occur only when the nerve is subject to fresh external trauma, as in tardy ulnar paralysis, or increasing compression in a confined space by a growing aneurysm or tumor. It seems proper to conclude therefore that abundant distal neuro- tization is satisfactory proof for continuing good function despite a high degree of internal scarring seen in the central portion of the lesion. E. ADMINISTRATION The foregoing material is already sufficient in scope to indicate that the proper study of the peripheral nerve injury of warfare demands an exact organization of resources not only during the conflict but in advance of 633

such episodes. Mention has been made in the introduction of the fact that the proper organization of the neurosurgical centers, and of subsequent studies such as these, was handicapped by a lack of such planning. Some brief mention is required at this point of important administrative factors. These include personnel, equipment, and the debatable problem of a wound policy factor that has to do with the priority which the various tissues of the extremity possess for treatment at various time periods following wounding. Other details of the organization of diagnosis and treatment groups appear elsewhere in the text. 1. Personnel There is unanimous agreement among our investigators that the experi- ence of the surgeon is one important controllable factor in the care of peripheral nerve injuries. This is not reflected in the data of earlier chapters since the relationship between prognosis and training is a com- plex one. It is to be recalled that less well-trained surgeons in this field, that is, general surgeons, conducted these operations largely under the supervision of a neurosurgeon. Where training was studied in a single center (Gushing General Hospital (40)) over a period of consecutive years, prognosis or the extent of neural regeneration improved with expe- rience. Table 110 (p. 194) fails to confirm fully this impression. The corollary to this statement is that the trained neurosurgeon should con- trol the initial or neurosurgical evaluation of peripheral nerve injuries. It has been further shown, in separate centers, that fixed professional per- sonnel not subject to the vagaries of assignment shifts, will reflect their increasing experience in terms of both better peripheral nerve regeneration and limb rehabilitation. The minimal personnel for this team includes a neurosurgeon with ade- quate experience in peripheral nerve surgery and sufficient less-experienced surgeons to allow the performance of the required number of peripheral nerve operations per week; 1 ward surgeon or physician to aid each operat- ing surgeon with administrative detail and 1 neurologist with a specific interest in peripheral nerve injuries to supervise the pre- and post-injury evaluation of peripheral nerve injuries. With these should be integrated an orthopedic surgeon trained in hand injuries, a plastic surgeon, a phys- iotherapist and sufficient personnel trained in electrodiagnostic and elec- trophysiological procedures. The increasing importance of the hand sur- geon familiar with the rehabilitation of peripheral nerve injuries must be emphasized. This concept of the peripheral nerve team is based upon the declared urgency of peripheral nerve repair and upon the need of combining certain bone, blood vessel and soft tissue repair with that of peripheral nerve tissue within an early time period after wounding. A system which requires transfer of the patient from one center to another for each phase of repair, in order to reach experienced personnel in these fields, will obviously de- tract from the result to be expected when all of the specialized work can 624

be planned and integrated at a single hospital. For example, although nerve suture should receive priority, it is difficult of accomplishment when a major fracture contraindicates the prolonged flexion of all joints that may be necessary for nerve approximation. On the other hand, attention first to open reduction of the fracture results in below average nerve regen- eration when suture is accomplished months later. Only when orthopedist and neurosurgeon work together in combined surgical procedures can such obstacles to ideal management be overcome. 2. Equipment a. Essential (1) Peripheral nerve diagnosis and operating room charts. (2) Modern operating room equipment and supplies, including atraumatic .003 tantalum wire and atraumatic ophthalmologic silk suture material. (3) Spring algesiometer. (4) Von Prey's hairs. (5) Spring scales for recording muscle strength. (6) Operating room nerve stimulator. b. Desirable (1) Chronaximeter. (2) Electromyographic unit, consisting of oscillograph, preamplifier and pre- cision stimulator. (3) Dermometer (Richter). (4) Skin temperature recorder. 3. Time and the Wound Policy Factor In extremity wounds, the concept regarding the extremity as a total or whole functioning unit is universally recognized. The implication of this concept is obvious. Neither bone, nor vessel, nor soft tissue, nor nerve must be treated by the narrow-visioned specialist as a single tissue. The extremity must be rehabilitated in terms of all tissues as a whole. This concept includes an intelligent appraisal of the relative value and the rela- tive ideal healing rate of the four major tissues of the extremity. There is ample evidence that the eventual outcome of an extremity wound depends in large part upon the extent of its peripheral nerve injury and the progress of peripheral nerve regeneration. This in turn depends upon definitive disposition of the peripheral nerve wound as soon as feasible following injury. One of the most important and definitive conclusions that has been derived from these data concerns the influence of elapsed time after injury to operation upon peripheral nerve regeneration. In terms of motor recovery, it seems for all nerves generally well established by these data that the final level of motor recovery is maximal for early sutures, and that subsequent delay in suture involves a variable loss which averages about 1 percent of maximal performance for every 6 days of delay. The very earliest, or emergency, sutures done within 19 days of injury do as well at follow-up as other early sutures, but only after half of them have been re- sutured. Although the effect of time seems clearly a general one, its mag- nitude varies not only by nerve but also by muscle within the set innervated 403930—57 42 *M

by a particular nerve. The effect seems especially large in distal muscles and in those innervated by the radial and the peroneal nerves. Whether the sutures were done overseas or in the Z/I in World War II was of no prognostic importance if one takes time into account; the real advantage of overseas suture seems adequately explained by the difference in time from injury to repair. The effect of time also confounds that of gap in motor recovery, there being a definite correlation between the two. Infor- mation about gap is of less prognostic value than information about time, but if time be ignored the effect of gap is a significant one; there is an aver- age loss of about 6 percent per cm. from the optimal motor recovery fol- lowing sutures on the shortest gaps, until the critical limit is reached when suture becomes impossible. In contrast to the striking influence of time upon motor recovery is the well-established fact that there exists no significant evidence in these data that elapsed time from injury to operation exerts any influence upon the recovery of pain and touch modalities. Indeed, worthwhile sensory return appeared in a limited series of cases when suture was performed 400 to 700 days after injury. The limitation of the material studied makes it impossible to delineate more exactly the postinjury interval for each nerve after which motor or sensory recovery is impossible. This appears an aca- demic point since functional motor recovery is exceedingly rare if operation must be postponed as long as 12 months postinjury and available data indicate sensory return should be sought, particularly for the median nerve, at any time period following injury. It these data concerning time are relevant, it seems of primary importance that a wound priority system be established in which all peripheral nerve injuries of warfare would be referred for treatment, complicated or not, to neurosurgical centers. Further evidence for this concept can be presented by a survey of the potential influence of bone, blood vessel, and major soft tissue injury upon neural regeneration. 4. Influence of Associated Injuries a. Bone. As earlier defined in this analysis, associated injuries were studied on the basis of a priori expectations that they might bear a direct and significant relationship to peripheral nerve anatomical regeneration. In this series, an associated bone or joint injury occurred in 47.7 percent of upper extremity nerve injuries and in 30.1 percent of lower extremity nerve injuries. No unusual type of peripheral nerve pathology is implicated in these injuries although the factors of compression and stretch from bone frag- ments must be considered. The very magnitude of the orthopedic task in the care of large numbers of casualties makes any consideration of the combined wound a very important one. On the other hand, no compli- cation of peripheral nerve injury is more apt to delay peripheral nerve repair if the group experience of the past be valid. If the repair of the respective tissues, bone and peripheral nerve, are compared in terms of 626

eventual limb function, it is self-evident that peripheral nerve repair takes precedence. Bone repair is always feasible in terms of time. This implied direction of the combined bone-peripheral nerve injury to the neurosurgeon during the early months of injury does not discountenance the great im- portance of combined repair procedures. Indeed, only by this approach can the practical problem of handling large numbers of patients be solved. On the average, a definitive suture was delayed 50 days by the presence of such associated injury or by other factors in turn associated with the orthopedic injury. In motor regeneration, the investigation was done on the basis of individual muscles, both power and ability to contract being examined in detail. Neither aspect of motor recovery appeared to have been influenced in any general way by the presence of such injuries or by the character of their healing. It is, however, interesting to note in table 75 on page 126 that the few muscles in which apparently deleterious effects were suggested by individual statistical tests are among those innervated by the radial and sciatic-peroneal nerves. The associated bone injuries, of course, involve the humerus and feaiur, and it is precisely here that the clinical problem really lies. Pain and touch thresholds were analysed as well in respect to the presence and character of any associated bone injury; no significant evidence of any deleterious influence was found. The British summary of sensory regeneration was also employed as a sensory index with results entirely consistent with those already given. In spite of the delay in peripheral nerve surgery, these regeneration studies suggest that a commendable approach to the combined bone-nerve injury was present under the conditions of World War II surgery. This was true and the importaace of such combined approaches to nerve-bone injuries and the importance of early peripheral nerve repair were promptly recog- nized in World War II. The concept must be fully developed that no orthopedic complication or method of therapy must interfere with pe- ripheral nerve repair within the early months after injury. Combined operative approaches must be encouraged and further developed. This is of major importance in high extremity injuries where the extent of periph- eral nerve regeneration is already embarrassed by the distance between point of repair and muscle or sensory end organ. It is in this class of injury that wound priority direction will insure maximal results. b. Arterial.31 These data have shown that 16 percent of all 3,656 nerve lesions had associated injuries to major arteries on the same limb. They were much more common in the upper extremity (24.4 percent) than in the lower (2.8 percent). When the site of the combined lesion is taken into consideration, usually high on the extremity, the weight of evidence favors the conclusion that an associated arterial lesion affects motor recovery adversely. If the per- centage of muscles contracting against resistance is employed in developing 11 The effect of nerve injuries upon the peripheral circulation is considered more extensively in a parallel VA Medical Monograph in preparation by Dr. Daniel C. Ellcin and associated investigators. 627

an estimate of the average magnitude of the effect of arterial injury, one finds that muscles affected by such injuries contract against resistance with only 82 percent of the frequency observed from muscles not so affected and of comparable site. In no sensory modality was the observed variation sufficient to conclude that such an associated injury had any effect upon sensory regeneration. This combined injury in an extremity manifests itself as a peripheral nerve injury in three aspects. (1) Tissue and therefore peripheral nerve ischemia. There is no simple periph- eral nerve injury more conducive to poor neural regeneration than that secondary to ischemia. With an otherwise intact peripheral nerve system, the treatment of peripheral nerve ischemia becomes a part of the treatment of extremity ischemia. Such therapy must be established at a very early time period after major vessel severance. If tissue ischemia is associated with major peripheral nerve injury, the therapy of ischemia holds prece- dence, with that of the peripheral nerve injury being carried out in the subsequent period following wounding. (2) Peripheral nerve injury may develop from compression of an expanding arterial aneurysm. Peripheral nerve tissue does not withstand prolonged pressure without axonal degeneration and without local ischemic changes. The appearance of a developing peripheral nerve paralysis in an extremity with an arterial aneurysm is a signal for immediate treatment of the vascular lesion. Among all of the late sequelae of vascular injuries, the expanding arterial aneurysm is the only vascular lesion that should command prece- dence over the therapy of peripheral nerve injury. Smaller arterial aneu- rysms may actually erode peripheral nerve tissue. (3) Major peripheral nerve injury may occur in any pathologic form with major vascular injury. The peripheral nerve injury should be evaluated as already described and a decision reached concerning operation. There is little doubt that a combined approach to peripheral nerve injury and vascular injury is preferable to separate operative interventions. Due to the com- plexity of the repair of ooth lesions, and due to the formidable nature of many arteriovenous aneurysms, it is a fact that in the past the repair of the peripheral nerve lesion has been deferred or, at best, has assumed a secondary role. This trend should be reversed. Except in the instance of expanding arterial aneurysms, the neurosurgeon must participate at all times in the repair of these combined injuries. Much further attention should be directed toward the proper care of these very crippling injuries of an extremity. Because of the anatomic contiguity of neural and vascular structures in the neck, combined vascular and neural lesions of the last cranial nerves are common. Many such patients undoubtedly succumb to immediate hemor- rhage. Treatment of the nerve lesion in those that survive needs only brief consideration. The neurological defect shows a strong tendency toward spontaneous resolution and direct repair of cranial nerve lesion is rarely indicated. More peripheral lesions of the spinal accessory and hypoglossal 628

nerves may demand operation but such peripheral lesions are uncommon with vascular injury. Residual paralysis of the vocal cord may precipitate respiratory difficulty or aspiration of fluids. Repair of the vascular lesion does not favorably influence the cranial nerve injury, and this particular group of cranial-peripheral nerve involvements should be the responsibility of the vascular surgeon directly. c. Soft Tissue. Roughly 10 percent of these cases were complicated by soft tissue injury that needed definitive plastic repair. A plastic procedure per- formed at the site of injury prior to nerve repair was found, particularly in the peroneal, median, and ulnar nerves, to be associated with an average loss of one-fifth in the expected percentage of muscles contracting against resistance. Any delay in definitive nerve suture as a result of such a repair was of too little moment to produce this effect, which probably depends in part upon loss of muscle substance. Sensory regeneration was not altered by the presence of a major plastic procedure. World War II experience demonstrated that any adverse time influence dependent upon prolonged plastic repair could be largely obviated by combined operative approaches. Peripheral nerve injuries cannot be repaired through split thickness skin grafts. Again, the concept of placing such combined injuries under neurosurgical care during the early months following injury will prevent the occurrence of splendid skin repair and a functionally useless extremity. The first task of the plastic surgeon is to enable the neurosurgeon to repair peripheral nerve tissue; his major task may well be completed at a single procedure. If not, it should be reserved for a later period of rehabilitation surgery. d. Chronic Infection. It has been pointed out that there is a considerable delay in nerve repair in cases with chronic infection. The effect of wound infection upon peripheral nerve regeneration is then a matter of elapsed time. In lesions complicated by infection, muscles were found to contract against resistance only about two-thirds as often as muscles not so com- plicated. There was no adverse effect upon sensory regeneration. The foregoing observations appear sufficient to make well founded the statements that peripheral nerve surgery must be a part of total limb surgery, that peripheral nerve regeneration is adversely affected by time as perhaps no other tissue is in the extremity and that in the presence of associated injury, combined reparative procedures are indicated. F. INFLUENCE OF TECHNICAL FACTORS OF SURGICAL MANAGEMENT UPON ANATOMICAL REGENERA- TION There remains to be reviewed the general influence of several technical factors concerned with surgical treatment as this influence is reflected in terms of peripheral nerve regeneration in these cases. Such a discussion would be repetitious of the detailed data presented in the chapters devoted to motor and sensory regeneration, and the reader is referred to summaries 629

on pages 191-197 and 308-309. It seems pertinent to point out that such technical factors as those concerned with suture material, cuffs, the trimming of nerve ends, and the minutiae of suture play little role in peripheral nerve regeneration, if conducted with reasonable skill and certitude, as compared to such factors as elapsed time, the management of associated injury, and the approach to peripheral nerve surgery as a part of total limb rehabili- tation. G. DISPOSITION TO DUTY Only 2.3 percent of the men with 1,890 peripheral nerve sutures studied in this representative sample returned to some form of duty status during World War II. The variations among the 7 major nerves in this respect was in the range of 0.6 to 4.2 percent and these data may be found in the last pages of chapter II. It also appears a fact that men with sutured peripheral nerve injuries were hospitalized on the average for 523 days in military hospitals as compared to 54 days for all the wounded in World War II. Some of this enormous time period devoted to hospitalization was, of course, spent on leave or on work furloughs. The number dis- charged from hospital prior to day 200 was negligible. These and other relevant data may also be found in chapter II. These studies upon anatomical and functional regeneration in this series of patients in terms of separate nerve injuries give considerable credence to the feeling that was held in World War II by experienced rehabilitation surgeons that time in hospital was, in general, excessive for these injuries. This feeling was reflected in part by the emphasis upon work furloughs by certain hospital centers where this manpower pool was used in noncombat or civilian type duties. This technique was not used widely and, in general, the convalescent hospital was developed to absorb a volume of patients quite well except for their treated nerve or other injuries. This mass of patients overwhelmed the capacities of available medical and ancillary personnel and scant progress was made in terms of exact observation of the extent, or the failure, of peripheral nerve regeneration. It appears essen- tial, therefore, to present in this survey of surgical implications the broad essentials of the results of peripheral nerve repair for separate nerves and certain suggestions concerning disposition from hospital. The latter in turn have to do only with the proposed period of active hospitalization. H. END RESULTS OF REPAIR, SUMMARY BY INDIVIDUAL NERVE The decision that the patient will not benefit from further hospitalization requires knowledge of the best that can be expected of his nerve injury and the degree to which his existing disability can be improved by orthopedic techniques. The former knowledge has been described in considerable detail in preceding chapters and is summarized below under separate nerve injuries. The latter information can only be obtained when the neuro- surgical center is associated with an orthopedic and hand center. Since 630

the benefits of tendon transfer can be largely realized in a period of 6 weeks, such an association of special skills tends toward adequate treatment, increased therapeutic experience, and prompt disposition. Since the prob- lem of achieving rehabilitation is quite different in arm and leg injuries, they will be discussed separately. 1. Lower Extremity Injuries In these follow-up studies, the regeneration of nerve injuries has been rated in percent of anatomical regeneration, reflecting the degree to which motor strength has returned to involved muscles, and the degree to which sensory thresholds have been lowered in the involved skin. At the same time, functional recovery has been analyzed and reported in terms of a percentage of functional recovery. In the case of the lower extremity, functional recovery is measured largely by the distance the patient is able to walk in reasonable comfort. In the lower extremity, extreme discrepan- cies may be apparent between these two factors of recovery. One patient with no anatomical regeneration secondary to a high sciatic nerve division may show 60 percent functional return if he is free of foot ulceration and if he has a satisfactory padded shoe and a brace to hold the foot in dorsi- flexion. On the other hand, examples are common of injuries to the sciatic nerve involving only the tibial component where nerve suture has given adequate motor power in all muscles of the calf, including the flexors of the toes, plus a reasonable appreciation of the modalities of pain and touch over the sole of the foot. This sensory return, however, may be so disagreeable, in spite of an adequately padded shoe, that walking for a distance of 2 blocks requires considerable effort. Although anatomical regeneration may be rated high yet this patient's functional recovery is of little value. The regeneration summaries of the sciatic, peroneal, and tibial nerves appear in tables 280 through 283. Although a poor correlation exists between anatomical and functional regeneration, it is not so poor as to preclude the advisability of sciatic nerve suture. Such sutures must be done early after injury if any type of ana- tomical regeneration is to be expected. If the patient with a high sciatic nerve division has had a technically good suture by an experienced neuro- surgeon, and if he has been fitted with shoe and brace so that he can walk comfortably without foot ulceration, a subsequent failure of improvement in nerve function is not an indication for reoperation. It seems clear that when a patient with a lower extremity nerve injury has secured complete functional rehabilitation, he will derive no benefits from further hospitaliza- tion. These studies have shown that no resuture of an original peroneal suture which had been performed adequately showed improved regenera- tion, and that resuture of a low tibial nerve injury that has been done adequately may increase or precipitate painful sensory reaction over the sole of the foot and increase functional disability. In most instances of uncomplicated lower extremity peripheral nerve injuries, discharge is indicated 3 to 4 months after peripheral nerve suture. 631

Table 280.—Regeneration Summary: Sciatic-Peroneal Motor recovery, by site in thigh tipper M Middle H Lower H All sites PI M' P" M' P1 M' P' M Tib. ant 54 37 29 49 34 31 26 21 60 43 35 57 24 20 29 25 72 59 48 68 37 28 15 35 59 43 35 55 32 23 Ext dig long Ext. hall long . . 28 27 Peron. long Sensory recovery Autonomic recovery Practical function Percent Pain threshold, 10 gm. or less . . . 24 Increased SR Absent sweati Percent 52 Median percc inal functio nt of nor- a 60 Patent Touch threshold, 5 gm . or less 19 n:f 65 1 Percentage (P) of affected muscles contracting voluntarily* and mean (M) relative power of affected muscles capable of movement against resistance. Table 281.—Regeneration Summary: Sciatk-Tibial Motor recovery, by site in thigh Upper K Middle H Lower % All sites P' Mi P' M' P' M' P1 M' Oast roc. & sol 94 56 94 53 91 62 95 85 65 67 59 64 60 37 34 34 Tib. post Flex. dig. long 17 18 36 37 33 21 27 41 41 MOO 55 Flex hall long 31 Inteross Sensory recovery Autonomic recovery Practical function Percent Pain threshold, 10 gm. or less 20 Increased SR Absent sweati Percent 55 Median perce nt of mil - i. . . 60 Perant Touch threshold, 5 gm. or less 18 aa 60 rnal funcrio 1 Percentage (P) of affected muscles contracting voluntarily, and mean (M) relative power of affected muscles capable of movement against resistance. ' Mean based on five cases.

Table 282.—Regeneration Summary: Peroneal Motor recovery All sites P' M1 Tih. ant 75 46 Hxt. dig. long 66 32 Ext. hall. long 54 36 Peron. long 71 42 Sensory recovery Autonomic recovery Practical function Percent Pain threshold, 10 gm. or less 38 Touch threshold, 5 gm. or less 37 Percent Increased SR 32 Absent sweating 63 Percent Median percent of nor- mal function 60 1 Percentage (P) of affected muscles contracting voluntarily, and mean (M) relative power of affected muscles capable of movement against resistance. Table 283.—Regeneration Summary: Tibial Motor recovery All sites P1 M1 Gastroc. & sol 94 64 Tib. post. . . 85 60 Flex. dig. long . 65 36 Flex. hall. long * * * * , * * 67 34 Inteross 52 32 Sensory recovery Autonomic recovery Practical function Percent Pain threshold, 10 gm. or less 29 Touch threshold, 5 gm. or less 26 Percent Increased SR 36 Absent sweating 63 Percent Median percent of nor- mal function 76 1 Percentage (P) of affected muscles contracting voluntarily, and mean (M) relative power of affected muscles capable of movement against resistance.

In summary, there is evidence that all peripheral nerve injuries of the lower extremity should not have any type of further operative intervention, even if anatomical regeneration is unsatisfactory. If an adequate early suture has been done and if functional rehabilitation has been completed, there is no need to hospitalize such patients, because evidence of neural regeneration may take 18 to 24 months to appear. This combined therapy should be completed by 4 months after suture and the patient discharged from the active neurosurgical center. 2. Upper Extremity Injuries Whereas the leg will do its job satisfactorily if it functions as a comfortable support with full movement at the knee, a hand to be useful requires active innervation of a variety of movements plus satisfactory sensation to at least the domain of the median nerve. Since one missing movement may make the difference between a useless and a relatively useful member, the re- sponsibility for terminating hospital care with an incompletely functioning hand is a heavy one. The regeneration summary of the median nerve appears in table 284. Table 284.—Regeneration Summary: Median Motor rcc by sit overy, High Low e P« M' P' M' Fl. car. rad 97 88 88 60 42 37 34 92 91 94 92 83 75 56 60 45 32 Fl dig prof #2 Opponcns . . 76 78 Abd. poll. brev 35 Sensory recovery, percent Autonomic recovery, percent Practical function, percent High Low Pain threshold, 10 gm. or less. . 39 49 49 Increased SR ... 43 Aver pe fur age (median) rcent of normal Touch threshold* 5 gm. or less. . . 48 Absent sweating 36 1 Percentage of affected muscles contracting voluntarily. 1 Mean relative power of affected muscles capable of movement against resistance. Even with the best sensory recovery after suture, the patient with a median nerve injury will still have difficulty in the organization of perceived pain and touch sensations that limit the hand's usefulness even though

mechanical function with visual aid be good. Therefore, a median nerve injury must be followed until useful function has returned to the thumb and fingertip. If sensation does not return at the scheduled time, reopera- tion is indicated since this is the only way of establishing improved sensa- tion. Reoperation may not be indicated if the nerve injury was extensive and everything possible, including nerve grafting, was done at the original procedure. Sensory recovery is often reasonably good but the hand may be handi- capped by loss of the opponens pollicis muscle preventing opposition of thumb pad to finger pad in picking up objects. Some patients with no opponens function compensate by the ulnar-innervated short flexor to the thumb. This is, however, not the rule. If the opponens has failed to re- cover on schedule, and if the patient can pick up small objects only by grasping them between the thumb and side of the index finger, compensa- tory tendon transplant is indicated. A variety of procedures for supplying opposition of the thumb have been described. With median nerve division above the elbow, the expectancy of recovery of normal thumb opposition is low. Tendon transplant repair of thumb opposition is indicated in such cases at an early period of hospitalization. Such a procedure seems prefer- able to waiting 14 to 18 months for opponens pollicis recovery, only to find that tendon transplant is required after all. In a few cases, there may be failure of innervation of the flexor digitorum longus and flexor pollicis longus with high median nerve injuries. The loss of flexion of the terminal phalanges of the index finger and thumb may be readily supplied by tendon transfers. In summary, a patient with a median nerve injury should not be dis- charged from the hospital until he has regained useful sensation in the autonomous sensory zone of the median nerve, unless poor regeneration must be accepted because of the extent of the lesion. Such a patient should always be provided, by tendon transfer, with the ability to oppose the thumb to the tips of the index and middle finger, if this function has not returned as a result of reinnervation. In median nerve injuries above the elbow, early tendon transfer for such function is indicated. Study center records indicate that this failure to provide thumb opposition was one of the major defects in the management of peripheral nerve injuries in World War II. Some patients were found still willing to undergo operation years after injury in an effort to regain thumb opposition that would give them a useful hand. The regeneration summary of the ulnar nerve is given in table 285. The patient who is left with an irreparable ulnar nerve paralysis, even including the forearm flexors, still has a relatively good hand. Although the fourth and fifth fingers may be useless and clawed into the palm, he is able to grasp heavy objects and pick up small objects with the radial three digits. Even with a complete paralysis, function of the hand may be rated at 60 percent. If, on the other hand, the fourth and fifth fingers can be extended and used for grasping, hand usefulness is increased to an 80 percent rating. These figures are expressed in terms of disability in the average white collar 635

Table 285.—Regeneration Summary: Ulnar Motor recovery, Hi f?h Lc Mr by site P> M' P' M> Fl rflr* jiJo -*..... . 96 66 97 72 Fl. dig. prof. 4-5 94 42 95 48 Abd. dig. quint 85 21 90 28 Add. poll . . 85 34 92 40 1 st dorsal inteross . . 78 26 87 31 Sensory recovery, percent Autonomic recovery, percent Practical function, percent High Low Pain threshold, 10 gm. or less. Touch threshold, 5 gm. or less. 29 31 Increased SR 45 Average (median) percent of normal 73 function. 39 Absent sweating 29 1 Percentage of affected muscles contracting voluntarily. 1 Mean relative power of affected muscles capable of movement against resistance. worker or laborer. The ability to set the lumbricals so that the fourth and fifth fingers may be extended is one of the last functions to return as the ulnar intrinsic muscles are reinnervated. Although the functional disability of the clawed fourth and fifth fingers is minimal as compared to loss of thumb opposition, patients should not be discharged until lumbrical action has been established by reinnervation or by tendon transfer. Ulnar regeneration is notably spotty and particularly so in high injuries. When poor regeneration must be accepted, tendon transfer is indicated early in the course of hospitaJization. When rein- nervation is proceeding normally, since the functional disability is slight, patients may be discharged to duty, to return for reexamination. Whether tendon transfer in these injuries is deferred or immediately con- templated, physiotherapy must provide relatively full motion in the inter- phalangeal articulations. Little can be done with fixed clawing and patients sometimes have not accepted amputation. The amount of exten- sion of fingers possibly by tendon work can be roughly predicted by noting the amount of passive finger extension possible when the wrist is held flexed to relax the flexor tendons. The tendon transfer technique is commonplace. Combined median-ulnar nerve injuries are extremely disabling since all the fingers become flexed into the hand and the only grasp possible is between the thumb and the side of the index finger. High injuries often 636

also involve a vascular component. Forearm injuries are often associated with massive soft tissue and bone injury. These studies show that in com- bined high injuries, regeneration to the forearm flexors is surprisingly good but that intrinsic muscle function never recovers sufficiently to permit thumb to finger opposition. This is also usually true in low injuries. Emphasis, therefore, must be placed upon the restoration of median nerve sensory function and upon restoring opposition to the thumb using the best of the available flexors. In addition, lumbrical function must be supplied to at least the index and middle fingers, so that they will reach out to meet the opposing thumb, rather than curling past it into the palm. The regeneration summary of the radial nerve is given in table 286. These studies indicate that anatomical regeneration may be of the highest order in radial injuries and that satisfactory functional recovery can always be anticipated. In instances of poor regeneration, adequate orthopedic techniques are available for restoring wrist and finger-drop and abduction of the thumb. When good wrist extension has been established by re- innervation adequate finger extension usually follows. Abduction and extension of the thumb customarily follows in 4 to 5 months and it is a moot question whether patients need to be kept under observation for this period of time. If wrist extension fails to appear at the scheduled time, the question of tendon transfer should then be considered. Table 286.—Regeneration Summary: Radial Motor recovery All sites P' M« Triceps Brach. rad Ext. carp* rad . . Ext. dig. comm. Ext. carp* ulnar. Abel. poll. long. Ext. poll. long. . Ext. poll. brev. . 100 92 94 89 93 78 83 79 69 68 49 47 50 37 37 36 Sensory recovery Autonomic recovery Practical function Percent Pain threshold, 10 gm. or less 51 Touch threshold, 5 gm. or less 56 Percent Increased SR 10 Absent sweating 20 Percent Median percent of normal function.... 78 1 Percentage (P) of affected muscles contracting voluntarily, and mean (M) relative power of affected muscles capable of movement against resistance. 637

It seems probable that the routine exploration of open wounds of the brachial plexus is neither profitable nor justifiable since, in the brachial plexus, a suture of elements supplying the forearm and hand seldom adds significantly to function. Proximal muscles such as the deltoid and biceps do occasionally secure useful recovery through suture. Cases must, therefore, be surveyed individually because of the complex nature of the injury. If exploration is done, in spite of evidence that it fails to add perceptibly to anatomic regeneration, postoperative emphasis must be placed upon ortho- pedic rehabilitation measures. I. FINAL NOTE The history of military neurosurgery demonstrates the fact that succeeding generations often fail to use the accumulated knowledge of the past. Much of the basic information in this report can be found in books by Foerster and by Pollock and Davis and in the Medical History of World War I, and in other monographs devoted to this subject. A large amount of data is also available in papers published during and after World War II in this par- ticular field. The concept of relatively early nerve suture carried out perhaps within 3 months following injury by an experienced team, the importance of peripheral nerve regeneration in total limb rehabilitation, the emphasis upon orthopedic hand surgery, the understanding of patho- logic changes in peripheral nerve tissue, and the trend toward exact neuro- physiological studies of peripheral nerve injury and regeneration are, however, relatively new. It is hoped that this final report of the peripheral nerve study centers will provide data in support of the surgical principles that have become accepted over the years and have been restated here. The military neurosurgeon, however, must not assume that these results cannot be improved. 638

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In peacetime, the busiest civilian clinics do not see enough peripheral nerve injuries to permit authoritative conclusions to be drawn about their management. In World War I, large numbers of these injuries were skillfully cared for by a small group of pioneer neurosurgeons, but there was no comprehensive follow-up and the opportunity to use the experience to the fullest possible extent was lost.

The publication of Peripheral Nerve Regeneration: a Follow-Up Study marks the end of a huge clinical research program that began in 1943, in the course of World War II. The program was participated in by more than a hundred of the neurosurgeons who served in the Medical Corps, as well as by many neurologists, neuroanatomists, neurophysiologists, neuropathologists, physical therapists, statisticians, and representatives of the administrative personnel of every echelon of command in the Army Medical Corps. Later the program was also participated in by representatives of the Veterans Administration and the National Research Council.

The primary purpose of this study was to evaluate the suites of peripheral nerve injuries sustained in World War II, with the hope of standardizing such treatment for future wars and, where possible, for similar injuries of civilian life. The secondary purpose of this study was to discover nerve injuries among veterans of all services that still required remedial measures. Peripheral Nerve Regeneration: a Follow-Up Study describes the final level of regeneration in representative cases of complete suture, neurolysis, and nerve graft, examines the apparent influence of gross characteristics or the legion, and or associated injuries, upon final result, and evaluates predictions of final recovery based on gross and histologic study of tissue removed at operation. The report of this study of postwar nerve regeneration provides for the surgeons of the future a body of information upon which they may guide repair of injured peripheral nerves and initiate needed orthopedic rehabilitation.

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