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Suggested Citation:"Recovery of Sensory Function." 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:"Recovery of Sensory Function." 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:"Recovery of Sensory Function." 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 243
Suggested Citation:"Recovery of Sensory Function." 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:"Recovery of Sensory Function." 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:"Recovery of Sensory Function." 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:"Recovery of Sensory Function." 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:"Recovery of Sensory Function." 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:"Recovery of Sensory Function." 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:"Recovery of Sensory Function." 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 250
Suggested Citation:"Recovery of Sensory Function." 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:"Recovery of Sensory Function." 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:"Recovery of Sensory Function." 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:"Recovery of Sensory Function." 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:"Recovery of Sensory Function." 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 255
Suggested Citation:"Recovery of Sensory Function." 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 256
Suggested Citation:"Recovery of Sensory Function." 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:"Recovery of Sensory Function." 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 258
Suggested Citation:"Recovery of Sensory Function." 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:"Recovery of Sensory Function." 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 260
Suggested Citation:"Recovery of Sensory Function." 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 261
Suggested Citation:"Recovery of Sensory Function." 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 262
Suggested Citation:"Recovery of Sensory Function." 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 263
Suggested Citation:"Recovery of Sensory Function." 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 264
Suggested Citation:"Recovery of Sensory Function." 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 265
Suggested Citation:"Recovery of Sensory Function." 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 266
Suggested Citation:"Recovery of Sensory Function." 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 267
Suggested Citation:"Recovery of Sensory Function." 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 268
Suggested Citation:"Recovery of Sensory Function." 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 269
Suggested Citation:"Recovery of Sensory Function." 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 270
Suggested Citation:"Recovery of Sensory Function." 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 271
Suggested Citation:"Recovery of Sensory Function." 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 272
Suggested Citation:"Recovery of Sensory Function." 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 273
Suggested Citation:"Recovery of Sensory Function." 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 274
Suggested Citation:"Recovery of Sensory Function." 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 275
Suggested Citation:"Recovery of Sensory Function." 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 276
Suggested Citation:"Recovery of Sensory Function." 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 277
Suggested Citation:"Recovery of Sensory Function." 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 278
Suggested Citation:"Recovery of Sensory Function." 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 279
Suggested Citation:"Recovery of Sensory Function." 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 280
Suggested Citation:"Recovery of Sensory Function." 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 281
Suggested Citation:"Recovery of Sensory Function." 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 282
Suggested Citation:"Recovery of Sensory Function." 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 283
Suggested Citation:"Recovery of Sensory Function." 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 284
Suggested Citation:"Recovery of Sensory Function." 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 285
Suggested Citation:"Recovery of Sensory Function." 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 286
Suggested Citation:"Recovery of Sensory Function." 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 287
Suggested Citation:"Recovery of Sensory Function." 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 288
Suggested Citation:"Recovery of Sensory Function." 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 289
Suggested Citation:"Recovery of Sensory Function." 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 290
Suggested Citation:"Recovery of Sensory Function." 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 291
Suggested Citation:"Recovery of Sensory Function." 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 292
Suggested Citation:"Recovery of Sensory Function." 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 293
Suggested Citation:"Recovery of Sensory Function." 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 294
Suggested Citation:"Recovery of Sensory Function." 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 295
Suggested Citation:"Recovery of Sensory Function." 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 296
Suggested Citation:"Recovery of Sensory Function." 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 297
Suggested Citation:"Recovery of Sensory Function." 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 298
Suggested Citation:"Recovery of Sensory Function." 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 299
Suggested Citation:"Recovery of Sensory Function." 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.
×
Page 300
Suggested Citation:"Recovery of Sensory Function." 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 301
Suggested Citation:"Recovery of Sensory Function." 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 302
Suggested Citation:"Recovery of Sensory Function." 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.
×
Page 303
Suggested Citation:"Recovery of Sensory Function." 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 304
Suggested Citation:"Recovery of Sensory Function." 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 305
Suggested Citation:"Recovery of Sensory Function." 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 306
Suggested Citation:"Recovery of Sensory Function." 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 307
Suggested Citation:"Recovery of Sensory Function." 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:"Recovery of Sensory Function." 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:"Recovery of Sensory Function." 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 V RECOVERY OF SENSORY FUNCTION Y. T. Oestcr and Loyal Davis A. INTRODUCTION In keeping with the guiding interests of the study as a whole, the objective of the sensory studies was two-fold: (1) to provide a more adequate and unbiased description of the final level of sensory return following injuries well defined as to extent and anatomic structure; and (2) to utilize differ- ential sensory recovery as an analytic tool for evaluating the effects of characteristics of the nerve injury, of any associated injuries, and of various details in their management. One cannot expect the content of routine clinical records, much less those of war injuries, to be commensurate in their detail and perfection with observations made years after the injury in accordance with a specific research protocol and in comparatively leisurely fashion. The practical objectives and the limitations of the base- line and interim observations, therefore, have guided the selection of sensory tests to be performed at follow-up and have directed interest away from many more basic problems in neurophysiology which might other- wise have been studied. From among specific sensory tests considered to be technically feasible and relatively reliable, a battery has been chosen to provide a representative picture of sensory performance at follow-up. To this description of sensory performance has been added a careful ana- tomic description of the original injury, with emphasis upon complete sutures. Sensory regeneration is not, therefore, studied here in its longi- tudinal aspect; rather it is assumed that a maximum return of sensation had occurred in each case prior to the follow-up examination, usually 4 or 5 years after definitive operation. Nor are the quality and extent of the sensory loss, either at injury or at follow-up, mapped in detail, as in earlier studies (24, 59, 60, 76). Finally, and purely as a matter of editorial convenience, the painful sensations of which patients complained either spontaneously or on examination and the limitation of function by sensory deficit are discussed in other chapters. The organization of the present chapter parallels that of chapter III on motor recovery. There is first a methodological part concerned with the selection of the specific tests of sensory function and with their tech- niques and instrumentation. The basic, descriptive portrayal of sensory status at follow-up is contained in a separate section which, unlike its counterpart in the motor chapter, is separate from the analysis of the 241

effects of certain characteristics of the nerve lesion itself, a separation enforced by the greater number of individual modalities requiring discus- sion here. Two final parts follow the organization of the motor chapter in detail, one on the influence of associated injuries, infections, and ther- apeutic procedures, the other on the apparent effect of certain technical aspects in the surgical management of peripheral nerve injuries. In preparing the tabulation plan for the sensory chapter, consideration was given to the possibility that the correlation between motor and sensory regeneration might be so high as to render unnecessary any study of the details of surgical management beyond that contemplated in the motor chapter. However, preliminary tabulations suggested that such was not the case and the tables underlying the present chapter follow very closely the pattern described in chapter I, including the detail of the injury- operation groups. The greater complexity and variety of the sensory determinations, as contrasted with the motor, render difficult the task of writing a single, unified chapter representing the work of all five peripheral nerve centers. In many ways it would have been more adequate, and certainly more satisfying for the workers in each center, to have analyzed and reported upon their own data. However, the original plan of the entire study was predicated upon a common, integrated analysis and it is on that basis that the present chapter proceeds. Conspicuously absent from it are the results of many special sensory studies made in individual centers, espe- cially Chicago, where the sensory examination was most complete. It is hoped that the ancillary data may be presented in subsequent reports from individual centers. B. METHODS OF EVALUATING SENSORY RECOVERY At the initial January 1947 conference it was pointed out that there then existed very little information on the specific level of sensory return, by modality, which could be expected following injuries of known extent, and that both practical and scientific interests would be served by the careful assessment of individual modalities. However, since a large-scale, cooperative survey was being planned, and it was agreed that uniform, comparable examinations should be made routinely, it was plain that the standard examination must not be overly elaborate, and that individual follow-up centers should be encouraged to supplement the standard examination with additional determinations of their own choosing in the light of their special interests. Emphasis was, therefore, placed on the more reliable and more objective aspects of sensory response to stimulation, and many tests originally proposed for the standard examination were not chosen. Moreover, when the time came to prepare a code for the statistical analysis, it was realized that the handling of data on areas of sensory loss would present difficulties, and that the most reliable observations were those pertaining to the area of isolated nerve supply (autonomous zone). 242

Accordingly, the mapping of total areas of diminished or absent sensibility was discontinued except in individual centers, notably Chicago, where there were special interests in the material. The Chicago center also made some observations on the loss of sensory response to temperature and to vibration. At the January 1947 conference tentative agreement was reached on the content of the sensory examination, as follows: Mapping of area of loss of touch. Mapping of area of loss of sensitivity to temperature. Mapping of area of loss of superficial pain sensation. Determination of deep pain response at tip of fingers and toes. Mapping of two-point sensitivity. Tinel's sign. At the first planning conference in November 1947 the above list was confirmed, and the standard forms thereafter designed for the project called for specific mapping of areas of sensory loss. The Chicago center printed these forms with provision for an additional distinction between areas of diminished touch (or superficial pain) response and areas of complete loss. At the Chicago conference in January 1949 it was decided to abstract from the sensory examination only the superficial pain and touch thresholds for the autonomous zones, together with the pain and touch responses to deep pressure, and to summarize sensory regeneration on the basis of the scale developed by workers associated with the British Medical Research Council (68). The tests of temperature sensation and two-point discrimination, and the determination of Tinel's sign, were dropped from the list of standard sensory tests. Later, as trial coding proceeded, the group was persuaded to add to the abstract for statistical purposes tests of position sense and localization of stimuli, although these had been omitted from the original protocol. 1. Pain. Pain was considered in terms of deep pain resulting from pressure, as on the tips of fingers and toes, and of superficial pain resulting from graded pinprick. The superficial pain threshold was determined by means of Lewey's spring algesiometers (42) which were made and calibrated at the same source. The examiner applied the pointed end of this instrument to the appropriate area and exerted steady, gentle force. The end-point was read in grams/mm2 pressure. The observations on the autonomous zone were scaled as follows for analysis: a. No sensation of pain. b. Deep pressure pain only. c. Superficial pain sensation to 40 gin./mm1. d. Superficial pain sensation to 30 gm./mm'. e. Superficial pain sensation to 20 gm./mm1. /. Superficial pain sensation to 10 gm./mm2. g. Superficial pain sensation to 6 gm./mm1. h. Superficial pain sensation to<[6 gm./mm'. 243

Although the Chicago charts, and the early charts of the other centers, contain further data of undeniable value on the extent of any deficit in pain sensibility, the data on the autonomous zone are surely the most reproducible, especially since examiners were loath to block adjacent nerves. The five centers were compared, prior to the statistical analysis, on the basis of completely sutured nerves, completely divided at injury, and with no associated nerve injury. The proportions with thresholds of 10 gm or less were compared for sutures of median, ulnar, radial, and peroneal, and with thresholds of 30 gm. or less for the tibial, and appeared to be reasonably homogeneous except that New York ratings were much les* favorable on peroneal sutures. Although the specifications for selecting the cases for these comparisons were so rigorous that the number of cases per center was not large, and in consequence the comparisons are not very powerful in the statistical sense, at least gross comparability of examinations seemed assured. Later, when all the ratings of individual centers were compared in more detail, it became plain that the centers did vary con- siderably in their use of the categories "no pain sensation," "deep pressure pain only," and threshold below 6 gm. Also one center (Chicago) almost never observed thresholds of 30 gm., 20 gm., and 6 gm. and concentrated its readings on the other categories of the classification. 2. Touch Touch was approached in parallel fashion. Dr. Lewey devised a care- fully standardized series of von Frey hairs, also made centrally and cal- ibrated at the Philadelphia center, which all follow-up centers employed. Although the Chicago observations, and those made early in the other cen- ters, extended to mapping the entire area of loss or diminution in touch sensibility, when the material was coded for statistical analysis attention was confined to the autonomous zones. The following scale was used: 0. No sensation, or threshold in excess of 50 gm./mm' 1. Deep pressure felt with 50 gm./mm' 2. Deep pressure felt with 35 gm./mm' 3. Deep pressure felt with 25 gm./mm2 4. Superficial pressure felt with 16 gin./mm' 5. Superficial pressure felt with 5 qm./mnv 6. Superficial pressure felt with 3 gin./mm' 7. Superficial pressure felt with <3 gm./mm1 The study of center variation in rating touch thresholds was made along the lines already described in connection with the pain threshold, and considerable center variation was found for each of the four nerves sampled (median, ulnar, tibial, and peroneal). The only systematic feature of this variation was the greater tendency of one center (San Francisco) to report thresholds of 3 gm. and a lesser tendency to report "no sensation, or threshold in excess of 50 gm." In addition, however, the Chicago center almost never reported thresholds of 50, 35, 16, and 3 gm. Consideration was given to the possibility of analyzing the touch data by center, but since 244

only one center deviated in a gross way, and accounted for only about 13 percent of the data, this was not done. One member of the study group (Dr. Lyons) has questioned the ability of the examiners to distinguish reliably between pain and touch reinnerva- tion, pointing out that it is very rare in this material (about 1.7 percent) that examiners reported no pain sensation in the presence of some touch sensibility. He also suggested that there may have been many instances in which regenerated superficial or even deep pain fibers were stimulated by the examiner and their reponse interpreted as sensation of touch or deep pressure. No statistical validation procedure seems applicable here, but the relationship between pain and touch assessments on median, ulnar, peroneal, and tibial nerves is shown in table 131. It will be seen there that 104/684 or 15 percent of the cases with a pain response were considered to have no touch response in contrast to the figure of 1.7 percent already given for absent pain sensitivity in the presence of a touch response. Table 131.—Correlation Between Pain and Touch Assessments, Median, Ulnar, Peroneal, and Tibial Nerves Pain response Touch response Absent Present Total Abse n t 83 104 10 93 Present 580 684 Total 187 590 777 3. Position Sense The test of position sense consisted of asking the subject to locate the postion of the moved part, screened from his view. The following rough scale was used in classifying the observations for statistical analysis: 0. No position sense 1. Position sense present but reduced 2. Position sense normal. Unfortunately, the test was performed only about half the time, and in one center (Chicago) almost never. The center comparison was confined to ulnar sutures of the set previously defined, and the resulting variation, exhibited in table 132, seemed sufficient to deny the ratings any real value in the subsequent analyses; accordingly the data are not presented here. 4. Localization Estimation of the patient's ability (without visual help) to localize stimuli applied to the affected autonomous zone was also a late addition to the standard sensory examination. If no significant pain or sensory 245

Table 132.—Center Variation in Reporting of Position Sense Number of lesions, by position sense Follow-up center Absent Reduced Normal Total A. Complete sutures on ulnar ' Boston 8 4 7 19 New York 2 2 17 21 Philadelphia 15 34 28 77 San Francisco 2 28 4 34 Total 27 68 56 151 B. All nerves, all types of lesion, all operations 31 21 124 176 New York 37 24 154 215 Philadelphia 157 264 390 811 San Francisco 12 246 58 316 Total 237 555 726 1*518 1 Injury produced complete nerve division, and no other nerve was injured on the same limb. perception existed, there was so obviously no ability to localize that many examiners did not even code this observation. For example, at the Philadelphia center, where localization was actually tested in about half of the cases, table 133 shows the relation between the performance of the test and the results obtained in tests on the pain and touch thresholds. With some pain or touch sensation, a stimulus, either pain or touch, was chosen, which was easily perceived. In other words, the test was one of localization of touch, where possible, and otherwise consisted in pain localization. When the observations on localization were abstracted for statistical study they were classified as follows: 0. Absent localization. 1. Split sensation. 2. Normal localization. Localization was tested in less than half the cases, and presence of anesthesia played a large role in the examiner's decision whether to perform the test. Unfortunately, when the observations were coded for statistical analysis all cases not tested were lumped together as unknowns, so that the material as coded cannot be used except in conjunction with the results of tests on pain and touch thresholds. Quite significant center variation was ob- 246

served; the percentages with normal localization, for example, are 31, 39, 60, and 62 for the 4 centers, on a range of 178 to 468 cases. Although the variation is less extreme than that observed for position sense, it is nevertheless too large to permit pooling of data with impunity. For these reasons the observations on localization possess only very limited useful- ness and their presentation in the following section has been limited to the data from a single center, Philadelphia. Table 133.—Percentage of Cases Tested for Localization in Relation to Results of Pain and Touch Stimulation, Complete Sutures on Median, Ulnar, Tibial, and Sciatic-Tibial Nerves Examined at Philadelphia Follow-up Center Number of lesions studied Localization test performed Pain threshold Touch threshold Number Percent None, or 50 gm. or None, or 50 gm. or >50 gm... less . . 91 47 7 168 9 11 29 3 118 0 12 62 43 70 0 40 gm. or less >50 gm... less Unknown on either pain or touch. Total 322 161 50 5. Modified British Summary of Sensory Regeneration The summary of sensory regeneration was adapted from a scale de- veloped by the Nerve Injuries Committee of the Medical Research Council of Great Britain (68, 70), and consists of the following rubrics: 0. Absence of sensibility in the autonomous zone. 1. Recovery of deep cutaneous pain sensibility within the autonomous zone. 2. Recovery of superficial pain sensibility. 3. Recovery of some degree of superficial cutaneous pain and touch sensibility within the autonomous zone. 4. Return of superficial pain and touch sensibility throughout autonomous zone, with overreaction and inability to localize stimulus. 5. Return of superficial cutaneous pain and touch sensibility throughout autonomous zone, with disappearance of any overresponsc. 6. Return of sensibility as above with the addition that there is some recovery of two-point discrimination within the autonomous zone. 7. Complete recovery. A precise comparison with the British classification is made in table 140, below. The modified British summary of sensory regeneration was adopted at the Chicago conference not only for its value as a summarizing device but also as a possible bridge between the results of the two studies. Exploration of center variation prior to tabulation did not extend to this 247

sensory summary, it having been supposed that any derived summary would merely have the characteristics of its components. Subsequent to the tabulation of the sensory data, however, the centers were compared as to their use of the British classification; 1,924 completely sutured nerves with no associated nerve injury were studied. The observed variation was very discouraging and had it been discovered prior to tabulation and analysis the material of each center would have been studied separately. Table 134 includes the comparative data on the median and ulnar; results with the tibial and sciatic-tibial were no better. Table 134.—Comparison of Follow-up Centers as to Classification of Sensory Recovery on Basis of British Summary, Completely Sutured Nerves With No Associated Nerve Injuries Percentage distribution of cases by British sum- mary Total Center Not more Pain and Pain and number than re- touch, with touch, with of nerves turn of overreaction no over- Total superficial and inabil- response pain (0, ity to local- (5, 6, 7) i l,2)i ize (3, 4) i Median sutures Boston 24 0 40 0 36 0 100 0 ,0 57 1 32 1 10 7 99. 9 28 New York 24.3 63.6 12. 1 100.0 107 Philadelphia 26.9 31.9 41. 2 100.0 119 San Francisco 4.0 48.0 48.0 100.0 5O Ulnar sutures 27.5 44. 9 27 5 99.9 69 67. 3 28.8 3.8 99.9 52 New York 35. 3 49.7 15.0 100.0 153 Philadelphia 34.8 16.7 48.5 100.0 204 7 9 50 6 41 6 100 1 89 1 These numbers define the grouping more specifically, in terms of the classification on p. 247. 6. Sensory Evidence of Anatomic Regeneration In each case a judgment was also made as to evidence of any anatomic regeneration of sensory fibers; similar assessments were made on the basis of the voluntary motor and the electrical tests, it will be recalled. Prior to 241

tabulation, statistical tests on the homogeneity of the five centers were con- fined to the proportion coded as having any evidence of anatomic regenera- tion, and these suggested that the centers were sufficiently homogeneous. Later, at the time the centers were compared as to their use of the British summary of sensory regeneration, the matter was restudied with specific attention to evidence of anatomic regeneration of sensory fibers and quite significant variation found, as may be seen in table 135. Two centeis seem to deviate excessively from the rest, Chicago in the direction of report- ing lower sensory return and San Francisco in the opposite direction, if the cases examined by the five centers are in fact homogeneous to begin with. Table 135.—Comparison of Follow-up Centers as to Percentage of Completely Sutured Lesions With Any Evidence of Anatomic Regeneration of Sensory Fibers, Nerves With JVb Associated Nerve Injury on Same Limb Percentage with evidence of regeneration, by nerve Center Median Ulnar Tibial Sciatic- tibia! Boston 87.5 71.4 91.7 85.7 96.2 80.6 76.4 90.7 86.3 95.6 100.0 58.6 96.7 88.6 100.0 81.3 50.0 Ohirago ....*..* New York 75.4 74.6 90.0 Philadelphia Total 88.2 87.3 85.6 73.6 The same pattern of deviation is evident in table 134 on the British sum- mary of sensory regeneration, and suggests the need for some consideration of any independent evidence of the homogeneity of the cases themselves, as contrasted with the sensory evaluations, as has been assumed. Study of the modified British summary of motor regeneration tends to confirm this assumption of homogeneity; no absolute confirmation is, of course, possible since the cases are different, but in comparison with an average rank of 3.0 which would be expected from 5 centers with homogeneous material the Chicago cases have an average rank of 2.5 and San Francisco 2.8 among all 5 centers, where the averaging is done over nerves.1* "Each center was ranked 1, 2, 3, 4, or 5 in order of relative excellence of results on each nerve (M, U, R, P, SP, and ST, only T being omitted for paucity of cases), and the 6 ranks thus obtained for each center were averaged; in entirely homogeneous material each center would have an expected average rank of 3.0, the average of ranks 1,2,3, 4, and 5. 403980—57- -18 249

7. Sources of Error In view of the essentially subjective nature of sensation, each and every determination requires the active cooperation of the subject under study. His status in respect to fatigue, willingness to cooperate, and immediate response to his environment, all combine to influence clinical observations on sensory performance. But in addition to these sources of variation, the evidence is that in this study the examiners themselves probably varied greatly in their interpretation of the patients' reactions to sensory stimuli. Of all the clinical observations and assessments abstracted for statistical study, only that on pain is surely adequate for direct pooling of data from the various centers. Since the extent of examiner-variation was not fully appre- ciated until after the main analysis had been completed on the pooled data it was not possible to extend the analysis to the individual centers to the extent desired. One result is that the effect of characteristics of the nerve injury, of associated injuries, and of variables in the management of the nerve injury, may be analyzed best on the basis of the pain threshold, but the observations on touch and the British classification have also been used. To the extent that variation among the study centers cooperating in the present investigation may be representative of variation among the general- ity of skilled neurological observers, however, the fact that the group of examiners was as large as five provides some assurance that their examina- tions will yield an average picture of all possible examinations, rather than one unduly influenced by a particular point of view. Although examiners were asked to extend their sensory examination to all 7 major nerves (M, U, R, P, T, SP, and ST), and observations on all 7 appear in the present chapter, chief reliance must of course be placed upon the median, ulnar, tibial, and sciatic-tibial injuries. For the radial, peroneal, and sciatic-peroneal the anatomic pattern of sensory supply varies so greatly from one individual to the next, both quantitatively and qualitatively, that the lack of earlier assessments of comparable extent and quality robs the follow-up examination of any real precision in the indi- vidual case. Indeed trained observers who look for early evidence of sensory regeneration following nerve injury have learned that no conclu- sions can be drawn from the degree of sensation present in the so-called autonomous zones of these nerves. On the other hand, the fact of great individual variation in the autonomous zones does not necessarily deny these nerves a role in any statistical analysis on the effects of characteristics of injury and of details of treatment, because there can be no reason to assume any correlation between individual aberrations in pattern of nerve supply and the nature of the lesion or the choice of treatment. Individual variation in the autonomous zones may be considered a random variable in such statistical analyses, tending to obscure the significance of any variation which may derive from the characteristics of injury and treat- ment. Since the statistical analysis is very largely concerned with ascer- taining whether particular factors influence individual modalities in some 250

general way common to all nerves, It has seemed unnecessarily restrictive to exclude the radial, peroneal, and sciatic-peroneal entirely and better to use them for whatever independent data they might contain. To the extent that the autonomous zones for radial and peroneal nerves are smaller than average, or even absent, examiners may be expected to exaggerate the frequency with which sensory fibers have regenerated. However, the data may be used to derive estimates of the likelihood of sensory return, it seems probable that such estimates will be unduly high, but to an un- known extent. Comparisons between these nerves and others, therefore, will not be reliable, although high-low comparisons within each of them may be. A true high-low difference might well be obscured by the error of observation arising out of individual variation in autonomous zones. In view of the interest which attaches to comparisons of lysed and sutured lesions and in view of the presumably incomplete nature of most lesions subjected merely to neurolysis, all cases of this type were reviewed " at the end of the project for positive evidence of sensory loss at the time of operation. C. DESCRIPTION OF SENSORY RECOVERY FOLLOWING COMPLETE NERVE SUTURE To avoid any bias which might result from the inclusion of possibly atypical cases, the tables for this section were restricted to the representa- tive sample defined in chapter I (p. 9). The scheme of presentation places emphasis upon the modality of sensation, the injured nerve, and the follow-up center (where necessary), in that order. 1. Pain For all the complete sutures in the representative sample, without regard to site of injury, extent of injury, presence of associated nerve injury, etc., table 136 provides a summary of findings by nerve. Subject to the qualifi- cations already mentioned, these data are presented as a factual summary of the major findings of the study with respect to deep-pressure and super- ficial pain. They constitute as good an estimate as one might hope to have of the ultimate level of pain sensibility following peripheral nerve suture in young males. Table 136 is comparable to table 49 in the motor chapter (pp. 88-89), which distributes each sample of affected muscles as to ultimate power following suture. As will be shown by the subsequent analysis, the special features of the wounds incurred by the men studied here, and the fact that they were received in battle, appear to have so little influence upon the ultimate extent of sensory regeneration that one cannot doubt the representativeness of the results as a sample of all peri- pheral nerve injuries in young males, provided they were treated by suture in the modern manner. 17 New York and Philadelphia cases were reviewed at those centers, Boston, Chicago, and San Francisco cases by personnel of the NRC Follow-up Agency. 251

Perhaps the chief lessons of table 136 are that the sutured nerve does regenerate in the great majority of instances, but that complete recovery of superficial pain does not often occur. Some pain sensation (deep or superficial) was observed in 88 to 94 percent of the upper extremities and in 77 to 84 percent of the lower. Some degree of pinprick sensation appears to have returned in 70 to 80 percent of the upper extremities and in 40 to 70 percent of the lower. A normal «6 gm.) pinprick threshold was recorded in 10 to 18 percent of the upper extremities, and in 6 to 16 percent of the lower. Table 136.—Deep-Pressure Pain Response and Superficial Pain Threshold for Completely Sutured Lesions, by Nerve, Autonomous %pne Only Threshold ' Median Ulnar Radial Tibial Peroneal Sciatic- Sciatic- peroneal tibial Percent Percent Percent Percent Percent Percent Percent No sensation of pain 8.5 11.9 5.8 19.0 15. 5 22.7 23.3 Deep-pressure pain only . . 13.6 18.1 14.9 23.2 15.5 27.6 35.7 Superficial pain, 40 gm. . . 14.5 16.2 15.9 15.4 17.0 17.0 12.8 Superficial pain, 30 gm. . . 8.0 8.2 6.2 5.6 4.3 4.4 3.4 Superficial pain, 20 gm. . . 11.7 12.1 6.2 6.9 9.4 2.9 4.3 Superficial pain, 10 gm. . . 17.3 17.5 22.1 16.8 11.9 11.8 11.9 Superficial pain* 6 gm. . . . 10.8 6.2 10.7 2.7 10.2 3.7 2.5 Superficial pain, <6 gm . . 15.7 9.8 18.1 10.5 16.2 9.8 6.2 Total 100. 1 100.0 99.9 100.1 100.0 99.9 100. 1 Number of lesions . . 236 430 188 95 142 163 129 1 About 6 percent of all cases were classified as "hypalgesia* unmeasured," and these have been distributed proportionately over the frequencies for thresholds from 40 gm. to 6 gm. When the nerves were compared on the basis of the data in table 136 it was found that the median and radial do not differ significantly, but that the ulnar is inferior to both. In the ulnar there are more poor results, and fewer good results, than in the median or the radial, but the discrepancies are not large even if statistically quite significant. In the lower extremity there are also quite significant differences, but they appear to depend entirely upon site, in that peroneal does not differ from tibial, or sciatic- peroneal from sciatic-tibial, but each sciatic component differs from its respective lower segment in the knee and leg. 2. Touch For all the complete sutures in the representative sample, without regard to site of injury, extent of injury, presence of associated nerve injury, etc., table 137 provides a summary of touch thresholds, by nerve. Like table 136 for pain 352

and table 49 for motor recovery, table 137 gives for touch the chief findings of the entire study. In certain major respects the distributions of touch thresholds are like those of pain thresholds, as would be expected from the fact that the two thresholds are highly correlated. In both instances entirely normal thresholds are by no means common; some sensation is reported in most instances, and there is real variation among the individual nerves. In one respect the distributions for pain and touch differ quite sharply. At the low end of the pain scale there is considerable scatter over the categories "no sensation of pain," "deep pressure pain only," and "superficial pain, 40 gm.," but at the low end of the touch scale there is much more concentration in the lowest category "no sensation, or thresh- old>50 gm." The touch threshold, in fact, seems to be moderately con- centrated in either the lowest region of the scale or in the region of 5 or 16 gm. applied as a superficial touch stimulus. At the high end of the touch scale the pain and touch thresholds look moderately similar. Table 137.—Deep-Pressure Touch Response and Superficial Touch Response for Completely Sutured Lesions, by Nerve, Autonomous %pne Only Threshold ' M U R P T SP ST No sensation, or threshold >-50 em. . Percent 18. 3 Percent 24.5 Percent 11.8 Percent 29.4 Percent 34. 8 Percent Percent 49.7 Deep-pressure felt with 50 gm 47. 2 Deep-pressure felt with 35 em . . 4.6 4.9 4.4 3.1 8.0 6.6 6.3 Deep-pressure felt with 25 em 5 4 7 9 6 7 15 9 8 1 6 6 4 7 Superficial pressure felt 23 2 27.7 21 1 14 3 22 8 9.9 21.3 Superficial pressure felt with 5 gm 21.8 16.6 20.0 13.5 10.7 8.6 9.4 Superficial pressure felt 11 4 9 6 17 8 11 1 4 0 5 3 5 5 Superficial pressure felt with <[3 gm 15. 3 8.8 18.2 12.6 11.6 15. 5 3. 1 Total 100.0 100.0 100.0 99.9 100.0 99.7 100.0 Number of lesions . . 241 433 187 143 95 163 129 1 About 5 percent of all cases were classified as "hypesthesia, unmeasured," and these have been distributed proportionately over the frequencies for thresholds from 50 gm. to 3 gm. The differences among nerves are rather like those for pain, lesions in the lower extremity exhibiting much less favorable sensory return than those in the upper, and the ulnar appearing at some disadvantage with 253

respect to both the median and the radial. The tibial and peroneal do not differ significantly as tested here, and this is also true of the sciatic-tibial and sciatic-peroneal components. The peroneal and sciatic-peroneal lesions differ significantly, but not so the tibial and sciatic-tibial. However, if one were to take a position on both peroneal and tibial nerves in relation to their respective components above and below the knee, it would surely be that the tactile sense returned better in the lower lesions. 3. Localization In the preceding section on methodology it was noted that data on localization could not be considered independently of those on pain and touch and that the several centers varied greatly in their reported results. For these reasons only the Philadelphia data are reported, and on the following assumptions: (a) If the pain threshold is absent or for deep-pressure only, and touch is absent or >50 gm.* any case coded as unknown for localization is regarded as having none; and (b) If either pain or touch is better than in (a), then cases coded as unknown for localization may be regarded as having the same distribution as those actually tested. Within the representative sample of complete sutures the Philadelphia center reported on 57 median lesions, 89 ulnar, 7 tibial, and 9 sciatic- tibial. Table 138 gives the details as reported on both median and ulnar lesions, and the results of applying the assumptions stated above. Ac- cording to these adjusted distributions, then, median and ulnar lesions are indistinguishable as to localization. The specific estimates are: Percentage of Cases Localization Median Ulnar None 23 29 Split 32 33 Normal 45 38 The best single estimate which could be made would be an average of the 2, or 26 percent absent localization, 32 percent split, and 42 percent normal. The observations in table 138 were also scrutinized for any association between split sensation and the level of the pain threshold for cases with a touch threshold below 50 gm., but the observed variation was found to be statistically insignificant. For both median and ulnar combined, split localization was reported in 46 percent of the cases with absent or deep pain threshold only (but with touch <50 gm.), and in 42 percent of the cases with a superficial pain response and touch threshold <50 gm. 4. British Summary of Sensory Regeneration As indicated earlier, the follow-up centers vary greatly in their use of the modified British scale. Here, however, where interest lies in the average picture of sensory regeneration in a representative sample of injuries, no purpose is served by presenting the ratings separately for each center; only the average of all centers seems useful for this purpose. 254

Table 138.—Pain and Touch Thresholds and Localization, Complete Sutures on Median and Ulnar Lesions in the Representative Sample, Philadelphia Data Only None or deep-pressure only Pain threshold Superficial pain felt Localization Touch threshold Touch threshold Total Absent or >50gm. <50gm. Absent or >50 gin. <50 gni. Ob- served Esti- mated Ob- served Esti- mated Ob- served Esti- mated Ob- served Esti- mated Median Unknown 16 0 1 0 0 o 7 0 0 None 1 17 1 1 0 0 0 o 18 Split 2 2 4 4 0 0 17 20 26 Normal 0 0 8 9 1 1 22 26 36 Total 19 19 14 14 1 1 46 46 80 Ulnar Unknown 37 0 8 0 2 0 27 0 0 None 2 39 1 2 1 2 3 4 47 Split . . 1 1 8 13 1 2 27 38 54 4 4 4 6 0 0 37 52 62 Total 44 44 21 21 4 4 94 94 163 In table 139 the entire representative sample of sutures is distributed according to the modified British rating. It will be noted from the detail of the classification scheme that the underlying observations extend well beyond the tests of individual modalities already summarized. The frequencies of table 139 support the same general conclusions already noted and in addition enable one to see just how rarely complete sensory recovery occurred. Statistical tests on the homogeneity of the individual nerves tell about the same story as before. The radial appears to have recovered better than either median or ulnar, but the advantage of the median over the ulnar is open to question (P=.09). Tibial and sciatic-tibial do not differ, but peroneal injuries appear to have recovered more completely than sciatic-peroneal. The two sciatic components are homogeneous, and the peroneal has some advantage over the tibial, according to these 255

ratings. The apparent superiority of the radial and peroneal nerves is somewhat suspect, for the reasons given in the preceding section. Since the summary classification was adapted from the one originally proposed by Highet for use by the Nerve Injuries Committee of the Medical Research Council of Great Britain, for the avowed purpose of making some comparison of British and American material, information appearing in the recent British report (70) has been abstracted in table 140 together with parallel data from the present study. The discrepancies are quite large, and at this writing remain unexplained. The British report contains no absolute failures among median and ulnar sutures, in contrast to 20 to 30 percent of the United States cases evaluated as having at most a deep pain response. Examiner variation, as judged by the differences among the five United States centers, would hardly produce such divergent results; the suggestion is strong that the series are basically different, either because of sampling considerations or because of differences in management. All five United States centers reported British SO and SI cases among both median and ulnar sutures. On the other hand, it would be an unusual selection which increased the sampling ratio at both the good and the bad ends of the scale, and it therefore seems likely that other factors are at work as well. Table 139.—British Summary of Sensory Regeneration for Completely Sutured Lesions, by Nerve Summary ' M U R P T SP ST Percent 11 1 Percent 12. 2 Percent 6.6 Percent 15.8 Percent 17.5 Percent 24.6 Percent 22.9 1 Deep pain only 11.9 16. 3 9.7 17.2 24.8 25.8 32.6 2 Superficial pain 2. 5 4. 1 4. 6 7.6 4. 1 6.0 3.8 3 Some superficial pain and touch 14.7 12.0 15.3 15. 8 14. 5 14.4 14.4 4 Superficial pain and touch, overreaction and poor localization . 5 Superficial pain and touch, no overre- sponse 28.2 13.9 24.0 18.9 13.3 25. 5 16.5 14. 5 26.8 10.3 16.2 15.9 5.3 6 Superficial pain and touch, -f 2-pt. dis- crimation 7.8 16.8 12.3 22.4 10.3 1.0 4. 2 4.5 / Complete recovery .... 0.2 .02 2.5 2.1 1.0 1.2 0.8 Total 99.9 100.0 99.9 99.8 100.0 100.2 100.2 Number of lesions . 244 441 196 145 97 167 132 1 See text (p. 247) for more detail on the classification, keyed to code numbers. 256

Table 140.—Comparison of U. S. and British Data on Sensory Regeneration, Complete Sutures on Ulnar, Median, and Tibial Nerves British code ' Median Ulnar Tibial U.S. British U.S. British U.S. British Percent 11.1 11.9 Percent Percent 12.2 16.3 Percent 0 0 Percent 17.5 24.8 Percent 19.5 53.4 0 Sensibility absent 0 0 1 J Vro pain 2 Some snpt-rfici.il pain and touch 17.2 28.2 13.9 46.7 15.2 16.1 24.0 18.9 54.0 15.2 28.2 18.6 26.8 10.3 18.6 2 + Superficial pain and touch, with overreac- t i o n 1.7 6.8 3 Superficial pain and touch, no overre- sponse 29.5 3+, 4 Superficial pain and touch, plus at least some 2-pt. dis- crimination 17.6 8.6 12.5 2.6 2.0 0 Total 99.9 100.0 100.0 100.0 100.0 100.0 Number of lesions . . . 244 278 441 390 97 118 1 The precise parallel between the two classifications is as follows: British U.S. 0. I. 2. Absence of sensibility in autonomous zone. Recovery of deep cutaneous pain sensi- bility within the autonomous zone. Return of some degree of superficial pain and tactile sensibility within au- tonomous zone. 2 +. Recovery of pain and touch sensibility throughout autonomous zone, with persistent overreaction. Return of superficial pain and tactile sensibility throughout the autonomous zone with disappearance of overre- sponse. 3+. Good localization with some return of two-point discrimination. 4. Return of superficial pain and tactile sensibility with the addition that there is recovery of two-point discrimination within the autonomous zone. 3. 0. Same as British. 1. Same as British. 2. Recovery of some superficial pain. 3. Return of some superficial cutaneous pain and touch, autonomous zone. 4. Return of superficial pain and touch throughout autonomous zone, with overreaction and inability to localize. 5. Same as British 3. 6. Return of superficial pain and touch, plus some two-point discrimination in autonomous zone. 7. Complete recovery. 257

Table 141.—Number of Cases in Each Classification of British Summary of Sensory Regeneration in Relation to Results of Specific Tests on Pain and Touch Thresholds, Complete Ulnar Sutures Pain threshold Touch threshold At most deep pressure with 50 gm. 16-35 gm. 5 gm. or less Total A. Absence of sensibility (code 0) At most deep-pressure pain 62 0 2 64 Superficial pain, 20-40 gm 0 0 0 0 Superficial pain, <20gm 0 0 0 0 Total 62 0 2 64 B. Deep pain, or some superficial pain (code 1,2) At most deep-pressure pain 45 19 8 72 Superficial pain, 20-40 gm 18 9 0 27 Superficial pain, <20 gm 10 6 0 16 Total 73 34 8 115 C. Superficial pain and touch, with overreaction (code 3,4) At most deep-pressure pain 1 11 3 15 Superficial pain, 20-40 gm 2 44 29 75 Superficial pain, <20 gm 2 26 42 70 Total 5 81 74 16O D. Superficial pain and touch, no overreaction (code 5,6,7) At most deep-pressure pain 0 8 1 9 Superficial pain, 20-40 gm 0 45 29 74 Superficial pain, <20 gm 0 30 67 97 Total 0 83 97 ISO Since agreement with British results is so poor, and the summary scale employed here is largely compounded of more specific tests of pain and touch responses, the United States data on the ulnar were subdivided by pain and touch as a further exploration of the basis of the summary classi- 251

IK ar ion by the five United States centers. Table 141 provides the detail of this subdivision, which employs somewhat coarser groupings of pain and touch than appear in tables 136 and 137. The cases studied here, it may be noted, are not confined to the representative sample, but extend to all examined cases in which the pain and touch thresholds were actually measured. From table 141 it may be seen that the summary rubric "absence of sensibility" follows very closely, as it must, the results of the specific tests of pain and touch; although the detail of table 141 is not sufficient to show it, 56 cases were explicitly coded as having neither pain nor touch response, 59 no pain response, and 61 no touch response, in the group of 64 cases. In the entire sample of 519 lesions, there are only 2 others with no pain response at all, and these were erroneously classified as "deep pain only." Apart from a very few possible errors of inclusion and exclusion, therefore, the use made of the British rubric "absence of sensibility" is a faithful summary of the tests of pain and touch thresholds, and it is difficult to see how technical errors in testing could explain the differences noted in table 140 between the United States and British results. The other British rubrics cover a mixed situation as to pain and touch thresholds. In the second group, detailed in panel B of table 141, one might have some question about the 15 cases with touch response to 16 to 35 gm. and pain thresholds of 40 gm. or below, but these cases con- stitute only 13 percent of the entire group. In the third group, shown in panel C of table 141, there are 15 cases which do not exhibit a superficial pain threshold, but 14 of them do have touch; there are 4 others with superficial pain thresholds, but no touch, or in all not more than 19 cases or 12 percent which might be questioned. In the fourth rubric of the adapted British classification there are 9 cases, or 5 percent, with no evident superficial pain threshold. In the main, then, the British clas- sification was used by the United States examiners in a fashion which at least grossly fits the observations on pain and touch, and it seems doubtful that technical error can explain the discrepancy between the two series. 5. Sensory Evidence of Anatomic Regeneration Usually some slight evidence of sensory regeneration was noted by examiners, so much so that the observation provides a rather insensitive tool for studying variation in sensory regeneration in relation to the inde- pendent variables which may be considered its determinants. In table 142 are contained the available data for all complete sutures in the repre- sentative sample. No great confidence can be placed in the absolute level of the percentages tabled there, in view of the considerable center varia- tion noted above in section B, but they may be considered to represent the average conclusions to be expected from careful neurological examina- tions. Only the sciatic lesions depart from the rather uniform pattern of 85 to 88 percent with sensory regeneration, and even for the sciatic the percentages are 70 to 75. 259

Table 142.—Sensory Evidence of Anatomic Regeneration Following Complete Suture, by Nerve Number of cases Percentage with sensory evidence Nerve Median 252 88.1 Ulnar 450 86.9 Radial 201 86.6 Peroneal . . 149 86.6 Tibial 97 84.5 Sciatic-peroneal . 168 70.8 Sciatic-tibial 134 74.6 D. DESCRIPTION OF SENSORY RECOVERY FOLLOWING NEUROLYSIS In view of the multiplicity of the sensory tests and the generally superior sensory recovery following neurolysis, this separate section is devoted to an exposition of the results obtained with neurolyses and to their comparison with sutures. The sample of neurolyses was limited, as in chapter III, to those drawn from rosters chosen for their reliability, and to those obtained from the Peripheral Nerve Registry, provided they fell within the sampling area for each nerve (p. 9). It will be recalled that lesions for which the definitive operation was neurolysis were specially scrutinized for sensory loss immediately prior to operation, in an effort to insure that the analysis could be carried out on limbs with adequate evidence of sensory loss. 1. Pain The lysed cases are not concentrated at any particular point on the scale, but in the upper extremity the most frequent pain threshold was be- low 6 gm., i. e., essentially normal. Table 143 provides a summary of all the lysed lesions in the representative sample, although for several of the nerves the samples are quite small. For every nerve except the radial there exists a set of cases with no pain sensation at all, and for every nerve there is an additional set with only deep-pressure pain; these observations seem to indicate that some of the lysed lesions might better have been resected and sutured. None of the following comparisons of two or more nerves yields statistical evidence of probable heterogeneity: Nerves compared: All seven nerves. Median v. ulnar v. radial. Peroneal v. tibial. Sciatic-peroneal v. sciatic-tibial. Peroneal v. sciatic-peroneal. Tibial v. sciatic-tibial. 760

Because of the small numbers of injuries representing several of the nerves, great emphasis cannot be placed upon the failure of the observations to distinguish the individual nerves from one another, but it does appear reasonably certain that any variation among them is probably not large. Table 143.—Deep-Pressure Pain Response and Superficial Pain Threshold for Lysed Lesions, by Nerve, Autonomous %pne Only Threshold ' M U R P T SP ST Percent Percent Percent Percent Percent Percent Percent No sensation of pain 2.7 4. 3 8.3 7. 4 18 9 11 5 Deep- pressure pain only . . 8.0 9.6 3.3 16.7 14.8 13.5 13.1 Superficial pain, 40 gm. . . 12. 5 15.0 21. 2 8.0 5.4 10.7 Superficial pain, 30 gm . . . 7.9 7. 5 4.6 4.0 2.7 8. 9 Superficial pain* 20 gm . . . 12.5 6.3 10.6 4.6 4.0 5.4 8.9 Superficial pain, 10 gm. . . 18.9 21.3 17.6 27.1 28. 1 24.3 25.0 Superficial pain, 6 gm .... 9.5 13.8 10.6 17.9 4.0 16.2 5.4 Superficial pain, <C6 gm . 28.0 22.3 36.7 20.8 29.6 13.5 16.4 Total. . 100.0 100 1 100 0 100 0 99 9 99 9 99 9 Number of lesions . . 75 94 30 24 27 37 61 1 About 6 percent of all cases were classified as "hypalgesia, unmeasured," and these have been distributed proportionately over the frequencies for thresholds from 40 gm. to 6 gm. One would expect somewhat better recovery of pain sensation following lysis than following complete suture; interest lies rather in the magnitude of the discrepancy. Table 144 provides a summary of the comparisons which were made, nerve by nerve, on a more summary grouping of the pain-response scale. Despite occasionally small numbers of cases, the superiority of the lysed cases seems quite clear. For lysed lesions the percentage with superficial pain thresholds of 6 gm. or less is about twice that for sutured lesions, on the average. The advantage stems not from the difference in surgery, of course, but from the very different nature of the underlying lesions; the incomplete (lysed) lesions do better than the complete. However, it is also plain that if surgeons had chosen, instead of neurolysis, resection and suture of the lesions studied here—neurolyses, the ultimate sensory recovery would probably have been less favorable than it actually was. As was noted in connection with table 143, how- ever, one might argue that 10 to 25 percent of the lysed lesions might have done better if resected and sutured. 261

Table 144.—Comparison of Completely Sutured and Lysed Nerve Lesions as to Deep-Pressure Pain Response and Superficial Pain Threshold in Autonomous %pne, by Nerve. Percentage distribution as to pain response Number of lesions Nerve and operation ' None or deep only 30-40 gin. 10-20 gm. 6 gm. or less Total 22.1 10.7 30.0 13.9 20.7 3.3 31.0 25.0 42.2 22.2 50.3 32.4 59.0 24.6 22.5 20.4 24.4 22.5 22.1 21.2 21.3 4.6 21.0 12.0 21.4 8. 1 16.2 19.6 29.0 31.4 29.6 27.6 28.3 28.2 21.3 31.7 23.7 32.1 14.7 29.7 16.2 33.9 26.5 37.5 16.0 36.1 28.8 47.3 26.4 38.7 13.2 33.6 13.5 29.7 8.7 21.8 100.1 100.0 100.0 100.1 99.9 100.0 100.0 100.0 100.1 99.9 99.9 99.9 100.1 99.9 236 75 430 94 188 30 142 24 95 27 163 37 129 61 L.. Ulnar S. . L.. Radial S . . L. . L.. Tibial S . . L.. L.. Sciatic-tibial S . . L.. 1 S distinguishes sutures from lyses (L). 2. Touch The results of the examination for the touch response are quite like those for pain, as may be seen from table 145. Every nerve is represented by cases with no touch sensation (or threshold >50 gm.) and by a significant number with normal «3 gm.) touch response. Variation among nerves never satisfies the criterion of statistical significance: Nerves compared: All seven nerves. Median versus radial versus ulnar. Peroneal versus tibial. Sciatic-peroneal versus sciatic-tibial. Peroneal versus sciatic-peroneal. Tibial versus sciatic-tibial. These tests were made on the basis of a summary grouping of various posi- tions on the scale, viz.: deep-pressure threshold of 35 gm. or more, deep- pressure threshold of 25 gm. or superficial threshold of 16 gm., and super- ficial threshold of 5 gm. or less. The frequencies of table 145 suggest that the nerves of the upper extremity probably do have some advantage over nerves of the lower with respect to the likelihood of no touch sensation (or threshold >50 gm.). Lysed and sutured lesions differ as to touch response about as they do as to pain, as may be seen from table 146. The advantage of lysed lesions is 262

not always marked (cf. the radial), but on the whole the only tenable con- clusion is that lysed lesions have a clear superiority over sutured, presumably because they were so different to begin with. For lysed lesions the per- centage with superficial touch thresholds of 3 gm. or less is about twice that for sutured. Again, however, it would appear that a significant pro- portion of the lysed cases would probably have benefited from suture, had it been possible to distinguish them from the rest. Table 145.—Deep-Pressure Touch Response and Superficial Touch Response for Lysed Lesions, by Nerve, Autonomous %pne Only Threshold ' M U R P T SP ST No sensation, or threshold >50 em. . Percent 9.3 Percent 10. 5 Percent 3.3 Percent 20. 8 Percent 14.8 Percent 19.4 Percent 21.0 Deep-pressure felt with 50 gm ] Deep-pressure felt with 35 gm > 3. 1 2.4 10.7 8.9 8.3 Deep-pressure felt with 25 em. 3. 1 6.0 3.3 4 4 4. 1 5.6 12.3 Superficial pressure felt 21 4 24. 1 21 0 17 8 20.0 33.3 29 8 Superficial pressure felt with 5 gm 29. 1 16.8 21.0 17.8 15.9 16.7 12.3 Superficial pressure felt with 3 gm 15.3 18.0 14.0 17.8 11.8 5.6 3.5 Superficial pressure felt with ^ 3 gm 18.7 22. 1 26.7 12.5 33.3 11.1 21.0 Total 100.0 99.9 100.0 100 0 99.9 100.0 99.9 Number of lesions. . 75 95 30 24 27 36 57 1 About 5 percent of all cases were classified as "hypesthesia, unmeasured," and these have been distributed proportionately over the frequencies for thresholds from 50 gm. to 3 gm. 3. British Summary of Sensory Regeneration In general the lysed lesions did very well. In the great majority of cases there was some return of superficial pain and touch, and complete absence of sensibility was relatively uncommon. Table 147 provides the basic data on all the neurolysed lesions classified as to the modified British scale for sensory recovery. Apart from a fairly marked difference between nerves of the upper and lower extremities, there is no very reliable variation among nerves. The following comparisons were made without finding statistical evidence of heterogeneity beyond that expected by chance: M v. U v. R, P v. T, SP v. ST, P v. SP, and T v. ST. 263

Table 146.—Comparison of Completely Sutured and Lysed Nerve Lesions as to Deep-Pressure Touch Response and Superficial Touch Threshold in Autonomous Zone, by Nerve Nerve and operation ' Percentage distribution as to touch response Number of lesions None or 35 gm. or more 16-25 gm. 5 gm. 3gm. or less Total Median S— 22.9 12.4 29.4 12.9 16.2 14.0 32.5 29.7 42.8 14.8 53.8 27.7 56.0 21.0 28.6 24.5 35.6 30. 1 27.8 24.3 30.2 22.2 30.9 24.1 26.5 38.9 26.0 42. 1 21.8 29.1 16.6 16.8 20.0 21.0 13.5 17.8 10.7 15.9 8.6 16.7 9.4 12.3 26.7 34.0 18.4 40.1 36.0 40.7 23.7 30.3 15.6 45.1 10.8 16.7 8.6 24.5 100.0 100.0 100.0 99.9 100.0 100.0 99.9 100.0 100.0 99.9 99.7 100.0 100.0 99.9 241 75 433 95 187 30 143 24 95 27 163 36 129 57 L— Ulnar S— lr- Radial S — L— Peroneal S — L— Tibial S— L— Sciatic-peroneal S — L— Sciatic-tibia! S — L— i S is used for suture, L for lysis. Table 147.—British Summary of Sensory Regeneration for Lysed Lesions, by Nerve Summary M U R P T SP ST Percent 5.2 Percent 5.2 Percent Percent 12 0 Percent 7 4 Percent 13 2 Percent 14 3 Sensibility absent o Deep pain only 3.9 6.2 3 3 16 0 7 4 10 5 6 3 Superficial pain 0 1 0 10 0 4 0 o 10 5 6 3 Some superficial pain and touch 10 4 19 6 10 0 12 0 7 4 7 9 14 3 Superficial pain and touch, overreaction and poor localization 20. 8 12.4 30. 0 12 0 37 0 15 8 27 0 Superficial pain and touch, no overresponse 29 9 20 6 16 7 32 0 22 2 31 6 17 5 Superficial pain and touch, + 2-pt. discrimination. . Complete recovery 24.7 5.2 25.8 9 3 20.0 12.0 0 11.1 2.6 7 9 7.9 6 3 10 0 7 4 Total 100 1 100 1 100 0 100 0 99 9 100 0 99 9 Number of lesions . . . 77 97 30 25 27 38 63 364

Lysed and completely sutured lesions generally differ to an extent which seems statistically reliable, but for the radial and the peroneal the differences are small and without statistical significance. Table 148 enables a compari- son to be made, nerve by nerve, on the basis of a summary grouping of the British scale. In the median and ulnar comparisons it will be noted that the lysed have not only fewer poor results but also many more good results, but in the sciatic comparisons the advantage is chiefly one of fewer poor results; even the lysed lesions do not often exhibit superior sensory recovery in the sciatic. Table 148.—Comparison of Completely Sutured and Lysed Nerve Lesions as to British Summary of Sensory Regeneration, by Nerve Percentage distribution as to sensory regeneration Superficial pain and touch, with overre- sponse (2*3,4) Superficial pain and touch, without overre- sponse (5) Superficial pain and touch, with at least some two-point discrimina- tion (6*7) Num- ber of lesions Nerve and operation 1 At most deep pain (0,1) • Total Median S . . 23.0 9.1 28.5 11.4 16.3 3.3 45.4 31.2 40.1 33.0 33.2 50.0 13.9 29.9 18.9 20.6 25.5 16.7 17.6 29.9 12.5 35.1 24.9 30.0 99.9 100.1 100.0 100.1 99.9 100.0 244 77 441 97 196 30 L.. Ulnar S. . L. . Radial S. L.. Peroneal S. . 33.0 39.9 14.5 12.4 99.8 145 L.. 28.0 42.3 14.8 50.4 23.7 55.5 20.6 28.0 45.4 44.4 36.6 34.2 34.1 47.6 32.0 10.3 22.2 7.8 31.6 5.3 17.5 12.0 2.0 18.5 5.4 10.5 5.3 14.2 100.0 100.0 99.9 100.2 100.0 100.2 99.9 25 97 27 167 38 132 63 Tibial S.. L. . Sciatic -peroneal . .S. . L.. Sciatic-tibial S . . L.. 1 S is used for suture, L for lysis. 1 Code numbers refer to categories defined (p. 247). 4. Sensory Evidence of Anatomic Regeneration When all the evidence of the sensory examination was weighed in an effort to determine whether any anatomic regeneration had occurred in sensory fibers, the examiner almost always came to the conclusion that some sensory fibers had regenerated. Table 149 contains a summary of the re- sulting data, by nerve. There is comparatively little variation among nerves when sample size is taken into proper account, but the suggestion is strong that the sciatic lesions did less well than the median, ulnar, and radial lesions. 403»30— 67^ -19 965

Table 149.—Comparison of Completely Sutured and Lysed Nerve Lesions as to Presence of Any Sensory Evidence of Anatomic Regeneration Following Operation, by Nerve Complete suture Neurolysis Nerve Number of lesions Percentage with sensory evidence Number of lesions Percentage with sensory evidence Median 252 450 201 149 97 168 134 88.1 86.9 86.6 86.6 84.5 70.8 74.6 79 100 30 25 27 39 63 93.7 93.0 93.3 76.0 92.6 76.9 79.4 Ulnar Radial Tibial Sciatic-peroneal Sciatic-tibia! Table 149 also includes the parallel data on complete sutures already cited in table 142. For none of the individual nerves does the disparity lie outside the range of chance, but for all seven nerves combined the advantage of the lysed lesions is clearly a quite significant one in the statistical sense, and yet a small one clinically. The forces of regeneration are too omnipresent, and regeneration itself too much a matter of degree, for a simple "yes or no" rating of this type to be very discriminating. E. INFLUENCE OF CHARACTERISTICS OF NERVE INJURY UPON SENSORY RECOVERY The preceding comparisons of lysed and completely sutured lesions pertain to the most important characteristic of the nerve lesion, namely, its precise anatomic nature and extent, but such comparisons are at best quite imperfect, for one can never know these facts for the lysed lesion as one can for the completely sutured. Other characteristics of injury which remain to be discussed here are the following—anatomic completeness of traumatic lesion preceding complete suture, specific site of lesion, and multiple lesions. 1. Anatomic Completeness of Traumatic Lesion Preceding Com- plete Suture On the basis of the operator's report, it will be recalled, each lesion was classified as one of complete division, partial division, or neuroma in continuity, prior to resection and complete suture. These distinctions are somewhat inexact, but the broad groups based upon them should differ greatly as to anatomic completeness of original lesion. Partial divisions were not often seen in the sample of complete sutures, and in most of the comparisons which follow they are either omitted entirely or combined with 266

the neuromas. Only complete sutures in the representative sample were used in this analysis. Comparisons of neuromas in continuity and complete nerve divisions provide little suggestion of heterogeneity for all nerves generally, although in two (ulnar and tibial) some evidence is found. Table 150 contains a summary of these comparisons, nerve by nerve, with the omission of all cases coded "hypalgesia, unmeasured." The discrepancy noted there for the ulnar is hardly credible as evidence of a real difference between the two types of lesions of which these cases are samples, for the complete sutures have an excess of both good and poor recoveries, the neuromas being more concentrated in the middle of the distribution. The discrep- ancy noted for the tibial has a fairly small probability (.015) but is intu- itively unreasonable in its direction; one would almost be willing to require that any discrepancy favor the neuromas in continuity. Despite these two aberrant tests, therefore, the only possible conclusion from these data is Table 150.—Pain Threshold and Anatomic Completeness of Lesion Prior to Com- plete Suture, by Nerve Percentage distribution of lesions as to pain threshold J Number of lesions Nerve and completeness of lesion ' None or deep- pressure only Median: Complete 20-40 gm. 10 gm. or less Total 24 25 34 42 43 100 159 Neuroma 32 100 44 Ulnar: Complete 35 24 31 49 34 26 100 99 291 Neuroma . . ... 87 Radial: Complete 22 21 25 37 53 42 100 100 111 Incomplete 34 Peroneal: Complete 33 36 23 36 44 28 100 100 82 47 Incomplete Tibial: Complete 37 72 29 12 34 16 100 100 59 25 Incomplete Sciatic-peroneal : Complete 56 50 23 21 32 100 100 102 Incomplete 18 50 Sciatic- tibial: Complete 62 16 22 16 100 100 87 38 Incomplete 58 26 1 Incomplete lesions include partial divisions and neuromas in continuity. ' Cases coded "hypalgesia, unmeasured" are omitted from this table. 267

that no important variation in pain threshold is associated with the classification of lesions as to anatomic completeness. In the observations on the touch threshold there is even less suggestion of heterogeneity associated with anatomic completeness of the original lesion, as may be seen from table 151. Table 151.—Touch Threshold and Anatomic Completeness of Lesion Prior to Complete Suture, by Nerve Percentage distribution of lesions as to touch threshold 2 Number of lesions Nerve and completeness of lesion ' None or 35 gm. or more 16-25 gm. 5 gm. or less Total Median: Complete 26.3 19.1 28.8 45.0 53.2 100. 1 100.0 160 Neuroma 27.7 47 Ulnar: Complete 30.9 30.3 32.9 40.4 36.2 29.2 100.0 99.9 298 Nrnmma 89 Radial: Complete 16.4 23.1 23.6 25.6 60.0 51.3 100.0 100.0 110 Incomplete 39 Peroneal: Complete 30.1 42.0 31.3 24.0 38.6 34.0 100.0 100.0 83 Incomplete 50 Tibial: Complete 42.4 56.0 33.9 12.0 23.7 32.0 100.0 100.0 59 Incomplete 25 Sciatic-peroneal : Complete 57.9 50.0 23.4 30.0 18.7 20.0 100.0 100.0 107 50 Incomplete Sciatic-tibia! : Complete 56.7 55.3 23.3 20.0 13.2 100.0 100. 1 90 38 Incomplete 31.6 1 Incomplete lesions include partial divisions and neuromas in continuity. ' Cases coded "hypesthesia, unmeasured" are excluded from this table. Other data on sensory recovery are less satisfactory for analytic purposes by reason of the considerable center variation discussed earlier, but are in keeping with the data presented here on pain and touch, and it may be concluded that the classification of completeness of lesion, based on the surgeon's gross examination at time of resection and suture, is of no prog- nostic significance for sensory recovery. 2. Site of Lesion Two related studies were made of site of lesion, the first based on the high-low classification already discussed, and the second on the detailed 268

classification of table 14 (p. 36). The first study was done on the repre- sentative cross-section of complete sutures. In the upper extremity high lesions are those involving the elbow, arm, or shoulder (below the brachial plexus) and in the lower extremity the knee and thigh. In addition, there is interest in the relation of each of the two sciatic components to its cor- responding lower segment, which has already been discussed earlier and need only be summarized here. Sensory recovery differs quite dramatically from motor recovery in respect to the role played by gross site; it will be recalled from chapter III that motor recovery was considerably better in low lesions than in high. Except for the advantage enjoyed by peroneal and tibial nerves over their respective sciatic components, none of the comparisons of gross sites yields a discrepancy outside the range of chance. Three sensory indices were employed in this analysis: pain, touch, and the British sum- mary of sensory regeneration. Table 152 provides the data on the pain threshold for median, ulnar, peroneal, and tibial nerves. In none of these comparisons does the discrepancy approach statistical significance, and despite some suggestion that lower lesions generally do a little better a combined probability on the discrepancies presented by all four nerves Table 152.—Comparison of High and Low Lesions as to Pain Threshold, Complete Sutures, by Nerve Percentage distribution as to pain threshold ' Number of lesions Superficial pain threshold Nerve and site At most deep- pres- sure Total Median: High 20-40 gm. 10 gm. or less Low 26.3 20.4 35.1 30.6 38.6 49.1 100.0 100.1 114 108 Ulnar: Hiff h 35.5 27.6 35.5 34.6 29.1 37.8 100.1 100.0 220 185 Low Peroneal: High 34.9 30.8 29.1 23.1 35.9 46.2 99.9 103 Low 100.1 26 Tibial: Hiirh 48.1 47.4 25.9 22.8 25.9 29.8 99.9 100.0 27 57 Low 1 The few cases with unmeasured thresholds have been omitted. 269

also lies well within the chance region. To assert that some small dif- ference may not exist would be to go beyond the data, but it is plain that, as tested here, they are consistent with the view that gross site of lesion has no real effect on the recovery of the pain response. It must be re- called from the earlier discussion of table 136, however, that tibial lesions differ significantly from sciatic-tibial, and peroneal from sciatic-peroneal. If the testimony of those comparisons is added to that of table 152, one would conclude that gross site does have a general effect, so that what- ever general conclusion one draws about the effect of gross site will depend on the view one takes of the discrepancies between the sciatic components and the segments distal to the sciatic sheath. The touch threshold varies much less than the pain threshold, as may be seen from table 153, but, of course, the basic observations are more affected by center variation than is true of those on pain. Neither singly nor jointly do the four comparisons included in table 153 meet the criterion of statistical significance used here. It was noted in the discussion of table 137 that peroneal lesions recovered much better than sciatic-peroneal, but that the advantage of tibial lesions was small enough to have easily occurred by chance. The data do not support any general conclusion as to the effect of site upon the recovery of touch, and yet the discrepancy noted between peroneal and sciatic-peroneal has a probability below .001. Table 153.—Comparison of High and Low Lesions as to Touch Threshold, Complete Sutures, by Nerve Percentage distribution as to touch threshold ' Number of lesions Nerve and site None or 35 gm or more 5 gm or or less 16-25gm Total Median: High 22.2 25.5 29.1 48.7 48.2 100.0 100.1 117 110 Low 26.4 Ulnar: High 32.6 28.0 36.2 33.2 31.2 100.0 100.1 221 193 Low 38.9 Peroneal: High . . . 36.4 26.9 29.9 23.1 33.6 99.9 107 26 Low 50.0 100.0 Tibial: Hieh 44.4 47.4 25.9 28.1 29.6 24.6 99.9 100.1 27 Low 57 1 The few cases with unmeasured thresholds have been omitted. 270

Sensory observations upon the peroneal are not too reliable, but apart from any prejudice in the attitude of the examiner one would expect this fact to operate equally for peroneal and sciatic-peroneal lesions. The summary classification of sensory recovery according to the British scale appears in table 154. None of the four comparisons there provides a discrepancy outside the usual chance range, and this is also true of all four taken jointly. As noted in the earlier discussion of table 139, this is also true of the tibial v. sciatic-tibial comparison, but peroneal lesions were rated much more favorably (P <.01) than sciatic-peroneal. Again, therefore, the evidence is far from satisfactory but suggestive of some effect favoring lower sites. Table 154.—Comparison of High and Low Lesions as to British Summary of Sensory Regeneration, Complete Sutures, by Nerve Percentage distribution as to British summary of regeneration Number of lesions Nerve and site Not more than re- turn of superficial pain Pain and touch with overreaction and inability to localize Pain and touch with with no no over- response Total Median: High 24.4 26.5 48.0 37.6 27.6 35.9 100.0 100.0 127 117 Low Ulnar: High 34.2 30.9 33.8 38.7 32.1 100.1 100.0 237 204 Low 30.4 Peroneal: High 42.7 32.1 33.3 28.6 23.9 39.3 99.9 117 28 Low 100.0 Tibial: High 48.3 45.6 44.8 39.7 6.9 14.7 100.0 100.0 29 Low 68 Site was studied in full detail for all sutures in the entire sample, not merely those in the representative sample and, for the pain threshold, table 155 gives a distribution of results for each site, by nerve. For each nerve a statistical test was made of the homogeneity of all sites in relation to one another. Other hypotheses, involving the relation of one particular site to another, were not formulated in advance and hence not tested. For both the median and the ulnar the observed variation by site is quite significant statistically, although this was not so when high and low lesions were compared in table 154. In part this is because the samples in table 155 are much larger (median lesions by 44 percent and ulnar by 31)

Table 155.—Specific Site of Lesion and Pain Threshold at Follow-up, Complete Sutures, by Nerve Percentage distribution as to pain threshold ' Number of le- sions ' Specific site Superficial pain threshold At most deep- pres- sure Total 20-40 gm. 10 gm. or less Median Upper ft arm 33.3 37.5 29.2 100.0 48 Middle f t arm 30.2 33.9 35.8 99.9 53 Lower ft arm . 20.0 22 5 57. 5 100.0 40 Elbow 19.0 42.8 38. 1 99.9 21 Upper ft forearm 22.2 11. 1 66. 7 100.0 36 Middle ft forearm 26.0 24.0 50.0 100.0 50 Lower ft forearm 25. 6 48.7 25.6 99.9 39 Wrist hand . . 12 5 37.5 50.0 100.0 32 Total 24.8 31.7 43.6 100. 1 319 Ulnar Arm, upper ft 42.8 35.7 21.4 99.9 70 middle ft 29 8 38 8 31 3 99. 9 67 lower ft 36.9 26.2 36.9 100.0 84 Elbow 31.3 39. 1 29.7 100. 1 64 Forearm, upper ft 33.8 32. 3 33.8 99.9 65 middle ft 22. 1 26.7 51.2 100.0 86 lower ft 23.7 35.6 40.7 100.0 59 Wrist, hand 26.5 52.9 20.6 100.0 34 Total 31.2 34.2 34.6 100.0 529 Radial Arm* upper Vi. . 20.7 28.3 50.9 99.9 53 middle ft 23.6 32.2 44. 1 99.9 93 lower ft 25.4 20.9 53.7 100.0 67 Total 23.5 27.7 48.8 100.0 213 272

Table 155.—Specific Site of Lesion and Pain Threshold at Follow-up, Complete Sutures, by Nerve—Continued Percentage distribution as to pain threshold ' Number of le- sions 2 Specific tite Superficial pain threshold At most deep- pres- sure Total 20-40 gin. 10 gm. or less Peroneal Thigh, lower f t 43.5 34.8 21.7 100.0 23 Knee 34.6 29.0 36.4 100.0 107 32 1 25.0 42 9 100 0 28 Total 35.4 29. 1 35.4 99 9 158 Tibial Thigh, lower f t . 1 Knee [ 48.7 23.1 28.2 100.0 39 Lefif. UDDCT ^4 . . 1 32.4 middle }i 32.4 35.3 100.0 34 lower ft 1 Ankle, foot W.1 15.6 31.3 100.0 32 Total 44 8 23 8 31 4 100 0 105 Sciatic-tibial Thierh. upDer ^A 65 6 18. 7 15 6 99 9 96 middle f t 49.0 27.4 23 5 99. 9 51 Lower % 57.7 23. 1 19.2 100. 0 26 Total 59.5 22.0 18.5 100.0 173 Sciatic-peroneal Thieh. UDDCT *A 53 3 25 0 21 7 100 0 120 middle ft 51 5 24 2 24 2 99 9 66 lower ft 59 4 25.0 15 6 100 0 32 Total 53.7 24.8 21.6 100. 1 218 1 Unmeasured thresholds omitted. 1 Braces indicate groupings made for purposes of statistical test on variation by •ite. S73

and in part because the high-low groupings serve to obscure some of the variation noted by specific site. For any particular site the samples are often quite small, and it may be for this reason that no uniform numerical pattern emerges from the median and ulnar data, but insofar as any trend may be discerned it appears to be a simple gradient favoring the lower lesions. In all the other nerves the observed variation is quite within the power of chance to produce and any suggestion of a uniform pattern seems confined, again, to the advantage possessed by tibial and peroneal lesions over their sciatic components. The touch response was studied in parallel fashion and significant variation observed only for the median and the sciatic-tibial. The data appear in table 156 and are confined to these two nerves. For the others the sites seem quite homogeneous in their recovery of the touch response. Even the differences noted for the median and sciatic-tibial are not very Table 156.—Specific Site of Lesion and Touch Threshold at Follow-up, Complete Sutures on the Median and Sciatic- Tibial Nerves Percentage distribution as to touch threshold ' Specific site Number of lesions3 50 gm. or more includ- ing no sen- sation 16-35 gm. 5 gm. or less Total Median Arm. uDDer *-4 ! 38.0 22.0 40.0 100.0 50 middle # L J 31.5 25.9 42.6 100.0 54 lower }4 i 9.8 36.6 53.7 100. 1 41 Elbow 14.3 33.3 52.4 100.0 21 19.4 38.9 41.7 100.0 36 middle % . . 24.0 24.0 52.0 100.0 50 lower ^ 1 25.0 37.5 37.5 100.0 40 Wrist, hand \ 19. 4 36.1 44.4 99.9 36 Total . . . 24. 1 30.8 45. 1 100.0 328 Sciatic-tibial Thieh UDDCF *A 65 3 16.8 17.8 99.9 101 middle H . . 49. 1 39.6 11.3 100.0 53 lower }£ 36.0 44.0 20.0 100.0 25 Total 56.4 27.4 16.2 100.0 179 1 Cases with unmeasured threshold omitted. 1 Braces indicate groupings made for purposes of statistical test on variation by site. 274

large, although like those involving the pain threshold they indicate a somewhat poorer recovery on the part of higher lesions. Clearly there is a reliable but weak association between specific site of lesion and sensory recovery, but whether it is true of only certain nerves or of all remains in doubt. Only in the median, ulnar, and sciatic-tibial lesions is there statistically reliable evidence of the association, and for these the evidence is by no means uniform: only for the median are both pain and touch significantly related to specific site. In addition, of course, ap- preciable differences were noted earlier between the tibial and the sciatic- tibial and between the peroneal and the sciatic-peroneal. In general, it would appear that the lower lesions do better than the higher, and that the very highest tend to do least well. Table 157 provides a partial sum- mary of the relationship, with emphasis upon the likelihood of no sensory response whatsoever in the autonomous zone, based on the modified British classification. Table 157.—Site of Lesion and Percentage of Cases With Absent Sensibility in Autonomous ^one at Follow-up, Completely Sutured Nerves, by Nerve Total lesions Percentage with absent sensibility Nerve Specific site of lesion Median 53 18.9 middle f t 59 13.6 lower J£ 43 7.0 Elbow 22 9.1 41 7.3 middle % . 55 12.7 lower y^ . . 50 6.0 Wrist and hand 40 15.0 Total 363 11.6 Ulnar. 77 18.2 middle % 69 11.6 lower ^£ 91 16.5 Elbow 70 8.6 74 8. 1 middle % . . 91 9.9 lower j£ . . - 68 13.2 Wrist and hand 41 9.8 Total 581 12.2 Radial Arm. uDoer 1A 57 5.3 middle^ 108 6.5 102 8.8 Total ... 267 7.1 275

Table 157.—Site of Lesion and Percentage of Cases With Absent Sensibility in Autonomous ^one at Follow-up, Completely Sutured Nerves, by Nerve—Con. Total lesions Percentage with absent sensibility Nerve Specific site of lesion Peroneal Thieh 25 16.0 Knee 123 16.3 Leg, ankle and foot 37 18.9 Total 185 16.8 Tibial Thigh, lower }{ 13 7.7 Knee . . . 28 21.4 15 13.3 middle % 27 3.7 lower ^ 25 24.0 10 20.0 Total 118 15.3 Sciatic-peroneal Thigh, upper ^ 132 26.5 middle f t 73 23.3 lower H 33 9. 1 Total ... 238 23. 1 Sciatic-tibia! Thigh, upper )£ 103 31. 1 middle H 54 16.7 lower y^ . . 28 7. 1 Total 185 23.2 3. Multiple Lesions The foregoing analysis is concerned almost exclusively with single lesions to a nerve trunk, but there were a handful of cases, here termed "multiple lesions," in which a single nerve sustained more than one injury. These cases are too few for refined statistical study, but those in which at least one of the lesions on the nerve was completely sutured are listed in table 158 as to pain and touch thresholds, and British sensory recovery. In an effort to determine whether the performance of multiple lesions, even in these few cases, was sufficiently inferior to meet a criterion of statistical significance, a rough comparison was made with other lesions on the basis of the frequencies presented in table 139. The result appears in table 159 and leads to the conclusion that the multiple lesions probably do not recover as well as single lesions. The percentage lying along the upper half of the scale is 32 for multiple lesions in contrast to an expectation of 54 percent, and the discrepancy has a probability of about .02 in a one- tailed test on the hypothesis that multiple lesions may not be better but 276

are no worse than single. Although the effect of a secondary lesion upon sensory recovery is less dramatic than that upon motor recovery (see p. 119), it is nevertheless real. Table 158.—Pain and Touch Thresholds and British Sensory Recovery Following Multiple Lesions to Single Nerves, and With One Lesion Completely Sutured Case num- ber Nerve Pain threshold gm.' Touch threshold gm.1 British summary 3 1074 Median 20 16 reaction. Unknown. 2043 Ulnar No sensation . ... 25 2053 Median Deep-pressure only. . . >50 Absent sensibility. 2111 Tibial. >50 Do 3194 Ulnar . . . 10 5 3275 Tibial. . 40 >50 touch. Deep pain 3286 Median 30 >50 3302 Ulnar 40 >50 Do. 3372 Radial 40 5 3408 do. . <6 <3 3446 Ulnar Deep-pressure only >50 Deep pain 3801 Median Hypesthesia. . . 16 Pain and touch* 2-pt 3857 do do Hypalgesia Pain and touch, no over- 4051 Ulnar Deep-pressure only 16 reaction. Do. 4063 4081 do Median .... do <6. . >50 <3 Deep pain. Pain and touch, 2-pt. 4107 Sciatic- 10.. 16 Deep pain. 4289 peroneal. Peroneal No sensation >50 Absent sensibility. 4297 Ulnar. . . . do >50 Do 4346 do do >50 Do 4379 Median Deep-pressure only 16 Do. 4464 do 10 5 Superficial pain. 5026 Ulnar 40 5 Pain and touch, no over- 5271 Sciatic- 10 16 reaction. Do 5414 peroneal. Ulnar No sensation >50 Absent sensibility. 7707 do. 10 16 Pain and touch* over- 8715 do Deep-pressure only 16 reaction. Deep pain 8725 do 10 25 Superficial pain 8783 Median <6 5 Pain and touch, over- reaction. 1 These are abbreviated statements of the rubrics given in full on p. 243. 1 These are abbreviated statements of the rubrics given in full on p. 244. The first rubric there "No sensation or >50 gm." is here abbreviated as ">50 gm." 1 These are abbreviations for the classes described in detail on p. 247. 277

Table 159.—Modified British Summary of Sensory Recovery for Multiple Lesions, at Least One Completely Sutured, All Nerves Combined Modified British summary Number of cases Code Interpretation Observed Expected ' 0 Sensibility absent 7 6 3.6 4.5 1. I 3.8 6.6 1 Deep pain onlv . . 2 Superficial pain 1 5 3 3 ... Some superficial pain and Superficial pain and touc localization. Superficial pain and touch Superficial pain and touch Complete recovery ... . touch 4 h, overreaction and poor * no overresponse . 5 3 2 1 4.6 3.6 .2 6 , plus 2-pt. discrimination . . 7 Total 28 28.0 1 For each set of cases involving a particular nerve the expected distribution of that number of cases was calculated from the distribution of all sutures on that nerve, and these expected values were then added together to provide a total for all 28 lesions. F. INFLUENCE OF ASSOCIATED LESIONS Although the decision to limit the statistical study of pain and touch response to the observations on the autonomous zone should obviate most of the influence of an associated nerve lesion upon the examiner's evaluation of the sensory recovery of another, it was considered wise to examine the data on the median and ulnar from this point of view. Also, there is practi- cal interest in the possible influence of associated injuries to bones and arteries, and of prolonged infection. It should be recalled, however, from the study of motor regeneration, that both bone injury and prolonged infection are confounded with time from injury to operation and no attempt has been made here to disentangle these variables. Although the original study of associated injuries extended to all the indices of sensory recovery, only the analysis of the pain response is in every case presented here. Finally, two sampling considerations should be borne in mind: (1) The study of associated nerve injuries was confined to the representative sample of complete sutures; and (2) other associated injuries were analysed on the basis of all complete sutures or all neurolyses in the entire study. 1. Associated Nerve Injury One nerve lesion was considered to have another associated with it only if both were on the same limb. It was not required of an associated nerve lesion that it be sutured, but only that it be a bonafide injury as determined by clinical signs. As noted in chapter II, the classification of associated lesions in the upper extremity extended to median, ulnar, radial, musculo- 278

cutaneous, and axillary; "pure" nerve lesions are those in which none of these nerves was also injured. In the analysis here, however, associated lesions involving the axillary and musculocutaneous were not used, so only when the median, ulnar, or radial nerve on the same limb was also injured is a lesion said to be a "combined" lesion here, i. e., to have an associated nerve injury. Table 160 provides a summary of the data on this question, from which it may be concluded quite definitely that the presence of an associated ulnar injury has no effect upon the sensory recovery of the median, and that the sensory response of the ulnar is not influenced by the presence of a median or radial injury. Table 160.—Presence of Associated Nerve Injury and Pain Response in Autonomous %pne at Follow-up, Complete Sutures on the Median and Ulnar Nerves Percentage distribution as to pain threshold * Number of cases Associated nerve injury At most deep pain 30-40 gm. 10-20 gm. 6 gm. or less Total Median None 26.0 19.0 26.0 29.0 100.0 100 Ulnar only 18.5 26. 1 28.3 27.2 100.1 92 Total 22.4 22.4 27.1 28. 1 100 0 192 Ulnar None 32.2 23.4 30.0 14.3 99.9 273 Median or radial 31. 1 23.5 25 0 20 5 100 1 132 Total 31.9 23.5 28.4 16.3 100.1 405 1 Cases with unmeasured hypesthesia are omitted. 2. Associated Bone or Joint Injury In the entire series of 3,656 nerve injuries there are 41 percent with injuries to bones or joints on the same limb, and generally at the same site; for the radial the percentage is much higher, and for the sciatic considerably lower. On the average a definitive suture was delayed about 50 days by the presence of such associated injury or by other factors in turn associated with the orthopedic injury. Only complete sutures are studied here. 279

Both time and site are confounded with associated bone or joint injury, but it has not seemed necessary to refine the analysis to take these factors into account since their influence would tend to reinforce any effect of bone and joint^ injuries, and no apparent effect was noted. For each of the major nerves the pain threshold was studied in relation to the presence of associated bone or joint injury and to the general char- acter of its healing process. Table 161 exemplifies these analyses with the data on the median nerve; only small, insignificant variation can be seen there. Similar tests were done for "pure" and "combined" nerve lesions with the same result. For all other nerves except the peroneal the situation is essentially the same and presentation of further data seems unnecessary. For all complete sutures on the peroneal, however, a moder- ately large discrepancy was observed but discounted as a chance aberra- tion on the ground that its direction seemed unreasonable: pain thresh- olds of 10 gm. or less were found in 25 percent of the cases with no asso- ciated bone or joint injury in contrast to 45 percent of those with some such injury. The touch threshold was also analysed in relation to the presence and character of any associated bone or joint injury and no significant evi- dence of any deleterious influence was found. Table 162 presents the observations on the median as a sample of the available material. The British summary of sensory regeneration was also employed as a sensory index in an effort to test the relationship between bone and joint Table 161.—Presence and Character of Any Associated Bone or Joint Injury, and Pain Threshold in Autonomous %one at Follow-up, Complete Sutures on Median Nerve Percentage distribution as to pain threshold ' Presence and character of associated bone or joint injury Superficial pain felt Number of lesions At most deep- pressure pain With 20-40 gm. With 10 gm or less Total Absent 25.7 21.1 26.9 31.8 32.2 30.8 42.5 46.7 42.3 100.0 100.0 100.0 179 90 52 Present: Normal healing Other ' Total 24.6 31.8 43.6 100.0 321 1 Cases with unmeasured hypesthesia are omitted. ' Requiring operative repair. 280

injury and sensory recovery following suture, and with results entirely consistent with those already given. The conclusion seems inescapable, therefore, that such associated injuries have no clinically important bear- ing upon sensory regeneration under the conditions of surgery prevailing in World War II. Table 162.—Presence and Character of Any Associated Bone or Joint Injury and Touch Threshold in Autonomous %pne at Follow-up, Complete Sutures on Median Nerve Presence and character of bone or joint injury Percentage distribution as to touch threshold ' Number of lesions None or 50 gm. or more 16-35 gm. 5 gm. or less Total Absent 23.8 23.9 28.3 31.4 26.1 34.0 44.7 50.0 37.7 99.9 100.0 100.0 185 92 Other • 53 Total 24.5 30.3 45.2 100.0 330 1 Cases with unmeasured hypalgcsia are omitted. 1 Requiring operative repair. 3. Chronic Infection Delaying Repair Whenever osteomyelitis or soft tissue infection intervened to an extent sufficient to delay repair of a nerve lesion, this fact was noted as a char- acteristic of the case and a statistical analysis was done to determine whether lesions with such associated infection did as well as those without. As already reported in chapter II, this classification segregates a group of sutures which, on the average, were done about 100 days later than sutures on lesions free of such complications. About 9 percent of all the 3,656 nerve lesions in the series were complicated by chronic infection as defined here. Pain, touch, and the British summary of sensory regeneration were all utilized in the investigation of the possible effect of infection, whether directly or through delay in repair. The observations on the pain threshold are summarized in table 163, by nerve, and seem at best somewhat equivocal. In view of the paucity of cases with infection, the scale for deep pressure pain and superficial pain was divided into two groups: (a) cases in which there was no pain sensa- tion, deep pressure pain only, superficial pain felt with 20 to 40 gm., or "hypesthesia, unmeasured"; and (b) superficial pain felt with 10 gm. or less. Even this gross dichotomy often fails to provide sufficient cases for any very sensitive test in the statistical sense. A discrepancy favoring lesions free 403030—87- -20 281

from complicating infection is noted for the median, radial, and sciatic- peroneal only, and one would not be inclined to consider the matter further were it not for the fact that the discrepancy for the radial has a proba- bility of .01 in a two-tailed statistical test. The combined probability from all 7 independent tests is .15, well within the range of chance variation. To the extent that one may require that any effect of chronic infection must be general for all nerves, therefore, the conclusion must be that no influence has been demonstrated. But if one entertains the possibility that any effect may pertain only to certain individual nerves, then greater weight should be placed upon the variation seen in the radial, although, as noted in the introduction to this chapter, sensory tests on the radial are none too reliable. The point of view adopted here is that any effect must be general, and that the observed variation provides no basis for believing that chronic infection exerts any influence upon the ultimate regeneration of pain fibers. Table 163.—Presence of Chronic Infection Delaying Nerve Repair and Recovery of Pain Response, Complete Sutures, by Nerve Infection present Infection absent Statis- tical tests2 Nerve Percent- age with threshold of 10 gm. or less i Percent- age with threshold of 10 gm. or less ' Number of cases Number of cases 34 23.5 34.1 20.0 38.9 44.4 10.0 23.5 324 524 244 163 108 213 164 40.7 32.1 48.4 31.3 26.9 21.1 17.1 NS NS Ulnar 44 25 18 9 20 17 Radial (**) Peroneal . . NS NS NS NS Tibial Sciatic-peroneal Sciatic-tibial NS 1 Among all tested, including those classified as "hypesthesia, unmeasured." 1 Results of statistical tests (two-taikd) abbreviated as follows: NS—Not significant. **—Significant at .01 level. Recovery of the touch response was studied in exactly the same fashion, the scale being divided into two groups: (a) those with absent touch response, response to 16 gm. or more, or "hypalgesia, unmeasured"; and those with touch response to 5 gm. or less. As noted for pain, few of the statistical tests involve enough cases to give one confidence that any effect would show through the large sampling fluctuation in percentages 282

entailed by such small numbers with chronic infection. Nevertheless, table 164 provides a summary of the available data, and it may be seen that, although only a single comparison (radial) provides a probability low enough to be of any interest, lesions without such infection have some numerical advantage in every nerve except the tibial, represented by only 9 cases with infection. Also, when the probabilities from the individual tests are combined into a single, overall probability judgment applicable to all nerves, it is found that the aggregate variation is greater than one would expect by chance. One must conclude, therefore, that the presence of chronic infection sufficient to delay repair, or the fact of such delay, or other factors associated with such infection, probably do tend to impair recovery of the touch threshold. Table 164.—Presence of Chronic Infection Delaying Nerve Repair and Recovery of Touch Response, Complete Sutures, by Nerve Infection present Infection absent Percentage with super- ficial touch threshold of 5 gm. or less ' Percentage with super- ficial touch threshold of 5 gm. or less ' Statisti- cal tests ' Nerve Number of cases Number of cases Median . 35 45 25 34.3 28.9 28.0 27.8 33.3 9.5 5.9 327 523 242 164 108 213 166 41.9 32.3 50.8 32.3 26.9 16.4 16.9 NS NS Ulnar Radial * Peroneal 18 9 21 17 NS Tibial NS NS NS Sciatic-peroneal Sciatic-tibial All tests combined * 1 Among all tested* including those classified as "hypalgesia, unmeasured." J Results of statistical tests (two-tailed) abbreviated as follows: NS—Not significant. *—Significant at .05 level. Although the observations upon which the British summary are based consist chiefly of those on the pain and touch response, in view of the dis- parity between the analyses on touch and pain it seems useful to present also the data on the British classification in relation to infection. This is done in table 165 which leads to the conclusion reached on the basis of the study of touch. Although, therefore, the observed discrepancies, even when taken collectively, do not uniformly have reliably low probabilities 283

under the test hypothesis of random variation, that based on the British summary lies between .01 and .02. The conclusion seems justified that infection delaying nerve repair, either directly or through the fact of such delay, is somewhat prejudicial to the recovery of sensibility following nerve suture, but that as a general effect it may be confined to the regeneration of touch fibres. Table 165.—Presence of Chronic Infection Delaying Nerve Repair and British Overall Assessment of Sensory Recovery, Complete Sutures, by Nerve Infection present Infection absent Statisti- cal tests > Nerve Number of cases Percentage classified as superior ' Number of cases Percentage classified as superior ' Median . . ... 35 46 25 18 10 21 17 22.8 26.1 24.0 38.9 10.0 0 0 331 534 254 167 109 217 169 30.8 32.0 48.8 24.0 13.8 12.0 10.1 NS NS Ulnar Radial * Peroneal NS NS NS NS Tibial Sciatic-peroneal Sciatic-tihial All tests combined * 1 Defined as at least recovery of superficial cutaneous pain and touch sensibility throughout autonomous zone, with disappearance of any overresponse. "Superior" thus corresponds to rubrics 5, 6, and 7 on p. 247. 1 Results of statistical tests (two-tailed) abbreviated as follows: NS—Not significant. *—Significant at .05 level. 4. Associated Arterial Injury About 16 percent of all 3,656 nerve lesions had associated injuries to major arteries on the same limb. It was pointed out earlier that presence of an arterial lesion is confounded with site, being most common in the upper arm and rare in the lower extremity. Any analysis is of necessity confined to the median, ulnar, and radial. The presence of arterial injury did not serve to delay nerve repair. Although all six sensory indices were studied in relation to arterial injury, for none of them was the observed variation sufficient to conclude that such associated injury has any effect upon sensory regeneration, and the observations on pain were chosen to exemplify the material used in the analysis. Table 166 provides a summary of the analysis, which extends to neurolyses on the median and ulnar as well as to sutures on all three 284

nerves. The pain scale was divided as described earlier in connection with table 163. The observed variation is unusually small even as an example of chance variation. Table 166.—Presence of Associated Arterial Injury and Recovery of Pain Response in Autonomous Zpne, Complete Sutures and Neurolyses in the Upper Extremity, by Nerve Arterial injury absent Arterial injury present Statis- tical tests' Nerve and definitive operation Percent- age with threshold of 10 gin. or less i Percent- age with threshold of 10 gm. or less ' Number of cases Number of cases Median: Suture 230 40.0 54.5 125 31 37.6 54.8 NS NS Lysis . . 55 Ulnar: 428 76 239 32.9 51.3 46.0 135 28 27 31.1 60.7 48.1 NS NS NS Radial' Suture .... All tests combined NS 1 Among all tested* including those classified as "hypesthesia, unmeasured." 1 Results of statistical tests (two-tailed) abbreviated as follows: NS*=Not significant. 5. Major Plastic Procedure at Site of Nerve Injury About 11 percent of all 3,656 nerve injuries had associated soft tissue defects at the same site and of sufficient extent to require plastic repair. Such repair was most commonly done at the knee or elbow, or in the fore- arm and leg, and involved the median, ulnar, peroneal, and tibial nerves. It was associated with an average delay of about 50 days in the nerve repair. Each of the six sensory indices was studied in relation to the presence of large soft tissue defects requiring plastic repair, but for none of them was the observed variation outside the chance range. The observations on pain, being attended with less extraneous variation on technical grounds, are presented in table 167 to illustrate the findings. Since pain response shows some relation to site of injury, and the confounding is not such as to reinforce any effect of the plastic repair, the comparisons have been confined to the so-called low lesions, i. e., below the elbow and knee. 285

Table 167.—Major Plastic Repair at Site of Nerve Injury and Pain Response in Autonomous %pne at Follow-up, Complete Sutures and Neurolyses, by Nerve, Low Lesions Only ' Plastic repair No plastic repair Statis- tical tests J Nerve and definitive operation Percent- age with threshold of 10 gm. or less 3 Percent- age with threshold of 10 gm. or less ' Number of cases Number of cases Median: 58 9 44.8 55.6 126 7 38.9 28.6 NS NS Lysis Ulnar: 70 11 27 65 38.6 36.4 44.4 32.3 195 22 9 10 36.4 59.1 22.2 10.0 NS NS NS NS Peroneal: Suture Tibial: Suture All tests combined NS 1 Low lesions are below elbow or knee. ' Among all examined cases, including those classified as "hypesthesia, unmeasured." ' Results of statistical tests (two-tailed) abbreviated as follows: NS=Not significant. G. INFLUENCE OF TECHNICAL ASPECTS OF MANAGE- MENT It is extremely difficult to assess the value of therapeutic procedures in the absence of experimental safeguards on the selection of clinical material, but in view of the great practical interest which inheres in the results of various choices which the surgeon may make as to therapeutic procedures, the analysis of sensory recovery has been extended to such details of manage- ment as seemed obtainable from the original military records. In keeping with the policy which dictated the sampling plan for the study the investigation has usually been done not on the representative cross- section but on all complete sutures available in the study, regardless of roster and sampling area. The present section is quite parallel in purpose, method, and scope to the section bearing the same heading in the chapter on motor recovery, and pertains only to complete sutures. 1. Number of Operations About 19 percent of all 3,416 lesions operated upon in this series had more than one operation. As pointed out earlier, most lesions for which the 216

definitive operation is a complete suture, and on which more than one opera- tion was done, were nevertheless sutured only once. The role played by multiplicity of operations is a difficult one to forecast because reoperation is performed on various indications, especially poor regeneration, because one expects reoperation to have a beneficial effect, and because the operations which are counted vary greatly in their probable effect. On the whole, however, in a system in which explorations were done quite liberally whenever there was doubt about the progress of regeneration following operation, one would expect the cases with more than one operation to have poorer prognoses. To obviate any influence of associated nerve injuries, the analysis was confined to so-called "pure" lesions on the median, ulnar, peroneal, and tibial nerves. Neither pain nor touch recovery alone reliably distinguishes sutures with a single operation from those with two or more, but classifica- tion by the British summary of sensory recover (table 168) does. The conclusion seems well founded that lesions with one or more operations before or after first suture have a poorer prognosis than those sutured and operated upon but once. The difference is not as large as one might expect, however. To provide a more detailed basis for estimating the extent of such selection, table 169 has been prepared by combining median and ulnar lesions. The advantage of the sutures with but one operation extends over the entire range of the British scale. Table 168.—Number of Operations and British Summary of Sensory Recovery, Complete Sutures on Pure Nerve Lesions, by Nerve Nerve One operation Two or more oper- ations Statis- tical tests2 Number of cases Percentage classified as supe- rior ' Number of cases Percentage classified as supe- rior ' Median. 138 291 100 86 31.2 34.0 28.0 15.1 41 94 45 6 22.0 21.3 17.8 16.7 NS Ulnar * Peroneal NS NS Tibial ** 1 Defined as at least recovery of superficial cutaneous pain and touch sensibility throughout autonomous zone, with disappearance of any overresponse. "Superior" thus corresponds to rubrics 5, 6, and 7 in table 169. ' Results of statistical tests (two-tailed) abbreviated as follows: NS—Not significant. *—Significant at .05 level. **—Significant at .01 level. 287

Table 169.—Number of Operations and British Summary of Sensory Recovery, Complete Sutures on Pure Median and Ulnar Lesions, Combined Single operation More than one operation British classification Percent 10. 3 Percent 15.6 0 Sensibility absent 1 EVc*p pain only 13.1 20.0 2 Superficial pain 5.4 6.7 4 Superficial pain and touch, overreaction and poor local- 12.8 14.8 25.4 21.5 17.9 14.1 14.7 7.4 0.5 0 Total .... 100. 1 100.1 Number of lesions 429 135 2. Interval From Injury to Definitive Suture The pitfalls of any analysis of the possible effect of time have been discussed at length in chapter III and need not be repeated here. At the outset the analysis of sensory recovery was confined to pure lesions on the median, ulnar, peroneal, and tibial, but no more than suggestive evidence of an effect was obtained. In view of the results of the analysis of motor recovery, which was conducted independently and showed time to exert a considerable effect upon the recovery of affected muscles, the study was broadened to include all seven major nerves, regardless of the presence of associated nerve injury, but the selection of cases was confined to the representative sample, i. e., sutures from the Army Registry within the sampling areas for individual nerves and centers. Both pain and touch thresholds were tabulated and studied in systematic detail, but neither for any individual nerve nor for all nerves jointly did there appear to be significant evidence that time exerts any effect upon the recovery of either modality. Table 170 provides the data for pain, table 171 for touch. These data are in marked contrast to those on motor recovery. Special interest attached to the likelihood of sensory regeneration follow- ing sutures done long after injury. Not many lesions were operated upon later than 1 year after injury, but there are perhaps enough to warrant separate review, and in tables 172 and 173 will be found information on definitive sutures performed at long intervals after injury. The material merely suffices to show that sensory regeneration can occur following sutures done after such long intervals. 288

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Table 172.—Pain and Touch Thresholds Following Complete Sutures Done 400 or More Days After Injury, by Nerve Number of Lesions, by Threshold ' Nerve Poor Fair Good Total A. Pain threshold Median . . . . 2 9 2 4 3 7 6 5 6 3 6 2 2 1 6 5 1 5 1 0 0 13 20 6 15 6 9 7 Ulnar Radial Peroneal Tibial Sciatic-tibial Total 33 25 18 76 B. Touch threshold Kf cdian * 3 9 0 5 2 8 5 5 9 3 5 3 1 2 6 14 22 6 15 6 9 7 Ulnar 4 3 5 1 0 0 Radial Peroneal Tibial .... ... Sciatic-peroneal ... Sciatic-tibial Total 32 28 19 79 1 As denned in tables 170 and 171. Table 173.—Sensory Recovery Following Complete Sutures at Intervals Greater Than 700 Days After Injury Case Pain threshold ' in gm. Touch thres- hold '-' in gm. Nerve No. British summary ' Median 3306 10 <3 Pain and touch, overreaction Median 3820 Hypesthcsia Hypalgesia. . and poor localization. Pain and touch, overreaction 3828 <6 16 and poor localization. Some pain and touch. Median . . . 3894 30 16 Pain and touch, with over- reaction and inability to localize stimulus. See footnotes on p. 294. 293

Table 173.—Sensory Recovery Following Complete Sutures at Intervals Greater Than 700 Days After Injury—Continued Nerve Case No. Pain threshold ' in gm. Touch thres- hold s in gm. British summary' Median . . 3906 Hypesthesia 16 Pain and touch, without over- 4253 16 response. Radial 3354 only. 50 response. Radial 3883 only. Hypesthesia Hypalgesia Pain and touch, overreaction Radial 3912 Hypesthesia Hypalgesia . . and poor localization. Pain and touch, overreaction Radial 5363 Unknown Unknown and poor localization. Ulnar 1175 Deep pressure 50 and poor localization. Deep pain only. Ulnar 2043 only. No sensation .... 25 Unknown. Ulnar 3221 6 . . 5 Pain and touch 2-pt discrimi- Ulnar 3851 Hypesthesia Hypalgesia nation. Pain and touch, overreaction Peroneal. . . . 3175 Deep pressure >50 and poor localization. Deep pain only. 3654 only. Peroneal 3854 40 >50 Superficial pain. Peroneal . . 3908 No sensation .... >50 Sensibility absent. Peroneal. . . . 4467 20 16 Pain and touch no overre- Peroneal 5003 40 . 16 sponse. Sciatic- 3802 Hypesthesia >50 peroneal. Sciatic- 3875 No sensation .... >50 Superficial pain. peroneal. Sciatic- 5142 40 >50 peroneal. Tibial 3854 10 >50 Superficial pain. Sciatic- 3875 No sensation .... >50 Superficial pain. tibial. 5142 40 >50 tibial. 1 These are abbreviated statements of the rubrics given in full on p. 243. 1 These are abbreviated statements of the rubrics given in full on p. 244. rubric there "No sensation or >50 gm." is here abbreviated as ">50 gm." 1 These are abbreviations for the classes described in detail on p. 247. The first 794

3. Echelon of Definitive Repair About 16 percent of all 3,416 nerve lesions operated upon received their definitive operation overseas. The distinction between a Z/I and an overseas suture is far more than a matter of time from injury to suture, for the Z/I sutures include many operations undertaken to improve the regeneration of lesions first sutured overseas. Complete sutures on median, ulnar, peroneal, and tibial lesions were studied for variation in sensory return in relation to echelon of definitive repair, but with inconclusive results. Table 174 contains the data on the pain threshold, according to which one would conclude that the selective factors distinguishing between overseas and Z/I cases were probably of no consequence. The one clear-cut difference involves the ulnar and betokens some superiority on the part of Z/I sutures, but as a set the four tests shown there lead to the overall conclusion that the echelon-groups differ by no more than chance. The same conclusion is more quickly forthcoming from table 175 on the touch response, and from table 176 on the British summary of sensory recovery. The undoubtedly real selective factors involved in the echelon-grouping simply do not modify the conditions of sensory recovery to such an extent that a small series such as this is, with all its restrictions, can be counted upon to exhibit the variation. Table 174.—Echelon of Definitive Suture and Recovery of Pain Response in Auton- omous Zone at Follow-up, Pure Lesions on Median, Ulnar, Peroneal, and Tibial Ov erseas Ifl Statis- tical Nerve Percentage with pain threshold of 10 gm. or less ' Percentage with pain threshold of 10 gm. or less * Number of cases Number of cases tests 2 Median 17 23.5 160 35.6 NS Ulnar 57 19.3 322 34.5 ** Peroneal 24 37.5 118 31.4 NS Tibia! 11 54 5 78 24.4 NS 1 Cases of "hypesthesia* unmeasured" are included in denominator. ' Results of statistical tests (two-tailed) abbreviated as follows: NS—Not significant. **—Significant at .01 level. 4. Length of Surgical Gap In view of the wide range of gap and its ready adaptability to an analysis of mean values, the study of sensory recovery in relation to gap was done on the basis of mean gap for cases of defined sensory recovery. The pain 295

Table 175.—Echelon of Definitive Suture and Recovery of Touch Response in Autonomous ^one at Follow-up, Pure Lesions on Median, Ulnar, Peroneal, and Tibial Ov jrseas tfl Statis- tical tests" Nerve Percentage with touch threshold of 5 gm. or less ' Percentage with touch threshold of 5 gm. or less ' Number of cases Number of cases Median 17 35.3 161 33.5 NS Ulnar 56 21.4 321 32.4 NS Peroneal 24 37.5 118 30.5 NS Tibial 11 27.3 78 28.2 NS All tests combined NS 1 Cases of "hypalgesia, unmeasured" are included in denominator. 1 Results of statistical tests (two-tailed) abbreviated as follows: NS—Not significant. Table 1 76.—Echelon of Definitive Suture and British Classification of Sensory Recovery at Follow-up, Pure Lesions on Median, Ulnar, Peroneal, and Tibial Ov :rseas 3 5/1 Statis- Nerve tical Number of cases Percentage superior ' Number of cases Percentage superior * tests2 Median 17 35.3 162 28.4 NS Ulnar 58 25.9 327 31.8 NS Peroneal 24 41.7 121 21.5 NS Tibial 11 36.4 80 12.5 NS All tests combined NS 1 Defined as groups 5 to 7 in table 169. 1 Results of statistical tests (two-tailed) abbreviated as follows: NS—Not significant. and touch thresholds and the British summary of sensory recovery were all utilized in this analysis, which was not confined to pure lesions and extended to all seven major nerves, but the resulting variation appears to lie well within the power of chance to produce. Table 177 contains the mean values corresponding to the subdivision of the pain scale. 296

Table 177.—Mean Length of Surgical Gap and Recovery of Pain Threshold in Autonomous <on« at Follow-up, All Complete Sutures, bv Nerve Sensory r ecovery ' Statis- tical tests' Nerve Po or Goo d Number of cases Mean Number of cases Mean gap, cm. gaP, cm. Median 196 5.44 128 5.26 NS Ulnar 353 5.40 170 5.95 NS Radial 136 5.08 110 4.95 NS Peroneal 110 6.37 55 6.04 NS Tibial 80 6.58 30 5.37 NS Sciatic -peroneal 173 7. 12 40 6.73 NS Sciatic-tibia! 139 7.32 29 6.86 NS 1 Gases classified as poor have no pain sensation or a threshold of 20 gm. or more, or were termed "hypesthesia* unmeasured"; cases classified as good have a threshold of 10 gm. or less. 1 Results of statistical tests abbreviated as follows: NS = Not significant. 5. Transposition or Extensive Mobilization as Special Operative Features Bulb sutures associated with transposition or extensive mobilization were omitted from this study, which extended to all major nerves regard- less of presence of associated nerve injury, provided the definitive operation was complete suture. Transposition and extensive mobilization are, of course, confounded with length of surgical gap, but it seemed unnecessary to take gap into account in view of the preceding analysis, and all com- parisons were made directly. For comparison with the lesions affected by transposition and extensive mobilization, those with no special operative features of any kind were chosen. The pain threshold seems entirely unaffected by transposition or extensive mobilization, as may be seen in table 178. Not so the touch threshold (table 179) in the lower extremity; for the two sciatic components the individual discrepancies are large and significant in the statistical sense, and both the tibial and peroneal comparisons yield discrepancies of similar sign if lesser magnitude. In the upper extremity, however, the differences are small and largely of opposite direction. It would appear that no single generalization would adequately cover all major nerves, and that the procedures of transposition and extensive mobilization are without effect in the upper extremity but rather prejudicial to the recovery of touch fibres in the lower extremity. 403930—87- -21 J97

Table 178.—Extensive Mobilization and Transposition and Recovery of Pain Response in Autonomous Zone, All Complete Sutures, by Nerve Lesions with no Lesions with trans- special features position or extensive mobilization Statis- Nerve tical Percentage Percentage test > Number with pain threshold Number with pain threshold of 10 gm. of 10 gm. or less ' or less ' Median 191 37.2 136 42. 6 NS Ulnar 141 29. 1 388 32.7 NS Radial 156 44.9 52 48. 1 NS Peroneal 121 33. 1 46 30.4 NS Tibial 57 33. 3 49 24.5 NS Sciatic-peroneal 131 22. 1 88 17.0 NS Sciatic-tibial 100 18.0 69 17.4 NS 1 Among all lesions tested, including those classified as "hypesthesia, unmeasured." ' Results of statistical tests (two-tailed) abbreviated as follows: NS- - Mot significant. Table 179.—Extensive Mobilization and Transposition and Recovery of Touch Response in Autonomous £one at Follow-up, All Complete Sutures, by Nerve Lesions with no Lesions with trans- special features position or extensive mobilization Statis- Nerve tical Percentage Percentage tests' with touch with touch Number threshold Number threshold of 5 gm. of 5 gm. or less ' or less ' 195 39 5 137 39.4 NS Ulnar 139 28. 1 389 32.9 NS Radial 154 44 8 54 55.6 NS Peroneal 120 34.2 48 31.2 NS Tibial 56 37.5 50 20.0 NS 130 20.8 89 9.0 * Sciatic-tibial 100 23.0 70 4.3 »* 1 Among all lesions tested, including any classified as "hypalgesia, unmeasured." ' Results of statistical tests (two-tailed) abbreviated as follows: NS = Not significant. *•= Significant at .05 level. **=Significant at .01 level. 298

Since the classification used in table 179 for the touch response is quite gross, there may be interest in the detailed distribution, over the entire coded range of touch response, for lesions with and without extensive mobilization or transposition. These data appear in table 180 for both sciatic components combined. Table 180.—Extensive Mobilization and Transposition and Recovery of Touch Response in Autonomous %pne at Follow-up, Complete Sutures on Both Sciatic Components ! Combined Lesions with no special features Lesions with transposition or extensive mobilization Touch threshold Percent 3.0 Percent 1 3 Hypalgesia* unmeasured No sensation, or ^>50 gm 42.6 57 2 Measured threshold : 5 0 gm 9.6 5.7 Meas>ired threshold: 25 gm 6. 5 9.4 Measured threshold: 1 6 gm 16.5 19.5 Measured threshold : 5 gm 11.7 1.9 Measured threshold: 3 gm 4.8 2 5 Measured threshold: <C3 gm 5.2 2 5 Total 99 9 100 0 Number of lesions 230 159 1 That is, sciatic-tibial and sciatic-peroneal nerves are here added together. 6. Bulb Suture Bulb-stretch preparatory to end-to-end anastomosis was not coded as an operation, but as a special operative feature. On the average the surgical gap in such cases was 2 to 3 times that noted in lesions with no operative features, but as already noted there is little or no evidence of an effect of gap upon sensory recovery. The proportion of complete sutures preceded by bulb sutures is not large, but if all 7 major nerves are studied there are about 120 bulb sutures distributed among them. The sampling is not confined to pure lesions but extends to all complete sutures. None of the several sensory indices (pain, touch, and British summary) provides convincing evidence that sensory regeneration is affected by bulb suture, and the observations on the pain threshold (table 181) may be taken as fairly representative. 299

Table 181.—Bulb Suture and Recovery of Pain Response in Autonomous %pne at Follow-up, All Complete Sutures, by Nerve Lesions with no special features Lesions first treated by bulb suture Statis- tical Nerve Percentage with pain threshold of 10 gm. or less ' Percentage with pain threshold of 10 gm. or less ' tests ' Number Number Median 191 141 156 121 37.2 29.1 44.9 33.1 33.3 22. 1 18.0 23 25 26 10 10 12 11 30.4 32.0 38.5 30.0 10.0 25.0 18.2 NS NS NS NS NS NS NS Ulnar Radial Tibial 57 131 100 Sciatic-tibial 1 Among all examined cases, including those classified as "hypesthesia, unmeasured." 1 Result of statistical tests (two-tailed) abbreviated as follows: NS—Not significant. 7. Character of Nerve Ends at Definitive Suture The prognostic significance of the surgeon's description of nerve ends, following resection and freshening, was sought in the eventual sensory re- covery of pure lesions on the median,ulnar, peroneal, and tibial, but none was found. Pain, touch, and British summary were studied for each nerve, but with generally negative results as illustrated in table 182 for pain. Table 182.—Surgeon's Description of Nerve Ends at Definitive Suture and Re- covery of Pain Response in Autonomous %pne at Follow-up, Pure Lesions on the Median, Ulnar, Peroneal, and Tibial Both distal and proximal ends normal Other Statis- tical tests1 Nerve Percentage with pain thresholds of 10 gm. or less ' Percentage with pain thresholds of 10 gm. or less i Number Number 97 199 29.9 36.7 36.8 27.3 30 62 31 46.7 33.9 22.6 23.8 NS NS NS NS Ulnar 68 44 Tibial 21 1 Among all examined lesions, including those classified as "hypesthesia, unmeasured." 1 Results of statistical tests (two-tailed) abbreviated as follows: NS—Not significant. 300

8. Tension Upon Suture Line The observations on tension are technically less satisfactory than most observations concerned with the details of management, as already noted. Only pure lesions on the median, ulnar, peroneal, and tibial nerves were studied as to the possible effect of tension upon sensory recovery. Pain, touch, and the British summary of sensory recovery were all included in these studies, but for none of the sensory indices was the variation associated with differences in tension of a magnitude which achieved statistical significance. The data on pain are presented in table 183 as representative of the findings. The lesions classified as having no tension are those in which the operator's report specifically stated that tension was minimal; cases in which the operator made no reference to tension were not used in the analysis. Table 183.—Surgeon's Description of Tension on Definitive Suture Line and Recovery of Pain Response in Autonomous %pne at Follow-up, Pure Lesions on the Median, Ulnar, Peroneal, and Tibial Nerves No tension Moderate or severe tension Statis- tical test « Nerve Percentage with pain threshold of 10 gm. or less l Percentage with pain threshold of 10 gm. or less ' Number Number Median 74 187 111 35.1 34.8 29.7 19 35 18 36.8 25.7 50.0 NS NS NS Ulnar Peroneal plus tibial i Among all examined cases, including those classified as "hypesthesia, unmeasured." ' Results of statistical tests (two-tailed) abbreviated as follows: NS=Not significant. 9. Suture Material As was observed in the initial study of motor recovery, there at first appeared to be marked differences in sensory return when lesions were grouped according to the material used in the definitive suture. Lesions sutured with silk appeared no different from those sutured with fine tantalum wire, but both were definitely superior to those on which the plasma glue technique was employed. Table 184 presents a summary of these initial comparisons on definitive sutures for "pure" lesions. As was shown in chapter III, however, the plasma glue series is not comparable with the tantalum and silk series in two major respects: (a) plasma glue sutures were generally done at longer intervals after injury; and (b) definitive plasma glue sutures were more often second or subsequent sutures. 301

Table 184.—Suture Material at Definitive Operation and Sensory Recovery, Pure Lesions Only, by Nerve Tantalum Silk Plasma glue Statis- Nerve tical No. of Percent No. of Percent No. of Percent tests' lesions supe- lesions supe- lesions supe- rior ' rior ' rior * A. Pain threshold Median 106 34. 9 38 47.4 25 8.0 ** Ulnar 257 35.4 80 22. S 29 27.6 NS Peroneal 91 29.7 42 42.9 + -f NS Tibial 59 27. 1 27 29.6 + + NS B. Touch threshold Median 107 31.8 38 52.6 25 8.0 ** Ulnar 258 30.2 77 32.5 29 27.6 NS Peroneal 91 34. 1 42 33.3 + + NS Tibial 59 27. 1 27 25.9 + + NS C. British summary Median 108 32 4 38 36. 8 25 4.0 ** Ulnar 262 32 8 80 28.7 30 10.0 * Peroneal 94 25.5 42 28.6 + + NS Tibial 60 16 7 28 14 3 + + NS 1 Superior is defined as follows: Pain: superficial pain felt with 10 gm. or less, among all tested* including any with "hypalgesia, unmeasured." Touch: superficial pressure felt with 5 gm. or less, among all tested, including any with "hypesthcsia, unmeasured." British summary: Both superficial pain and touch present, no overresponse. 1 Results of statistical tests abbreviated as follows: NS=Not significant. * ^significant at .05 level. **-=significant at .01 level. + Too few cases to tabulate. Since sensory recovery is unrelated to interval from injury to suture, the only controls which appear necessary are that the groups be defined by the suture materials used at the first operation and examined at the New York Center where all the plasma glue patients were seen. Controlled comparisons of this nature were made for median and ulnar nerves, and are summarized in table 185. Since it has already been shown that asso- ciated nerve lesions do not affect examiners' evaluations of sensory recovery, 302

table 185 is not confined to pure nerve lesions as is table 184, and there is actually a net gain in the number of plasma glue median sutures available for study. The use of these additional controls does not dissipate all the evidence of poorer sensory return following plasma glue suture, for the touch response of the median nerve continues to be inferior, but otherwise all the differentials of table 184 appear greatly reduced in table 185, and to such an extent that the only tenable conclusion is that sensory recovery following plasma glue suture is probably no different from that seen after sutures with tantalum and silk. Table 185.—Suture Material at First Operation and Sensory Recovery, All Median and Ulnar Lesions Studied at New York Center Tantalum or silk Plasma glue Statistical tests' Nerve No. of Percent No. of lesions Percent superior ' lesions superior ' A. Pain threshold Median 72 31.9 29 20.7 NS Ulnar 114 26. 3 27 22.2 NS Total 186 28.5 56 21.4 NS B. Touch threshold Median 72 26.4 29 6.9 NS Ulnar 114 21. 1 28 28.6 NS Total . . 186 23 1 57 17 5 NS C. British summary Median 71 54.9 29 69.0 NS Ulnar 115 52.2 28 50.0 NS Total 186 53 2 57 59 6 NS "As in table 184. ' Results of statistical tests abbreviated as follows: NS = Not significant. 10. Use of Cuff About one-third of the definitive sutures were protected by cuffs, almost always those made of tantalum foil. In only about 7 percent of the cases was it unknown whether a cuff was employed. All seven major nerves 303

were studied for variation in sensory recovery associated with the use of cuffs, and the selection was not limited to pure lesions. Pain, touch, and the British summary of sensory recovery were utilized in these compari- sons, and in each index the observed variation appeared to exceed that expected from a random process. Table 186 provides a summary of the observations on pain, and although for only 1 of the 7 nerves is the dis- crepancy statistically significant, it will be noted that in every comparison there is a differential in the same direction. When all seven tests are taken in combination it is clear that the evidence in favor of the cuff is statis- tically quite significant. Analysis of the touch response also provides fairly strong evidence in favor of the cuff (table 187). In one of the individual comparisons the discrepancy between the percentages with superior touch response attains statistical significance, and although for the ulnar the direction of the difference is counter to the rest, when all 7 tests are combined the overall probability is found to be <^*01. The evidence from the British summary of sensory recovery is even more definite. Table 188 distributes each nerve-cuff group according to a coarse grouping of the British scale. Almost uniformly the sutures accom- plished with the aid of cuffs look better at both ends of the scale. Table 186.—Use of Cuff at Definitive Suture and Recovery of Pain Response in Autonomous %pne at Follow-up, by Nerve No cuff used Cuff used Nerve Percentage with pain threshold of 10 gin. or less ' Percentage with pain threshold of 10 gm. or less J Statis- tical tests ' Number of lesions Number of lesions Median 211 322 145 125 71 125 99 35.1 30.1 43.4 29.6 25.4 14.4 14.1 119 194 104 43.7 33.5 48.1 36.8 34.3 28.9 22.5 NS NS Ulnar Radial NS NS NS Peroneal 38 35 97 71 Tibial Sciatic-peroneal * Sciatic-t ibial NS All tests combined ** 1 Among all examined cases, including those classified as "hypesthesia, unmeasured." 1 Results of statistical tests (two-tailed) abbreviated as follows: NS—Not significant. *—Significant at .05 level. **—Significant at .01 level. 304

Table 187.—Use of Cuff at Definitive Suture and Recovery of Touch Response in Autonomous %pne at Follow-up, by Nerve No Cuff used Cuff used Nerve Percentage with touch threshold of 5 gm. or less i Percentage with touch threshold of 5 gm. or less ' Statis- tical Number of lesions Number of lesions tests 2 Median 213 323 143 125 71 125 99 35.7 31.6 121 193 105 39 35 98 73 45.5 29.5 52.4 38.5 31.4 22.4 20.5 NS NS NS NS NS * Ulnar Radial 44. 1 26.4 21.1 10.4 13.1 Peroneal Tibial Sciatic-peroneal Sciatic-tibial NS All tests combined ** 1 Among all examined lesions, including those classified as "hypalgesia* unmeasured." ' Results of statistical tests (two-tailed) abbreviated as follows: NS—Not significant. *—Significant at .05 level. **—Significant at .01 level. As noted in chapter III, the decision to employ a cuff is probably related to characteristics of the case which have a bearing upon nerve regeneration. When a controlled motor comparison of cases with and without cuff was done by restricting the analysis to lesions with most favorable prospects for recovery (no associated injuries, short gaps, and fairly early time of operation), the advantage of cases with cuff disappeared. Accordingly, the same selection was made here and tables 186 and 187 were repeated. Unlike motor recovery, sensory recovery is not appreciably affected by these restrictions; a larger sampling variation is introduced by the fact of smaller numbers of cases, but no systematic shift appears in either the group with, or the group without, cuffs. In consequence, lesions with tantalum foil again appear to have recovered more fully than those without, although the margin of advantage is less certain and more variable in this smaller amount of material. Table 189 contains these data; statistical tests were done only on the totals for all nerves since each nerve is repre- sented by so few cases, and both for pain and touch lead to the rejection of the hypothesis that cases with cuff are no better than those without. 305

Table 188.—Use of Cuff at Definitive Suture and British Classification of Sensory Recovery at Follow-up, by Nerve Percentage distribution as to British classi- fication of sensory recovery At most superficial pain and touch with overreaction and inability to localize At least superficial pain and touch with disappear- ance of over- response Number of lesions Nerve and use of cuff No sen- sation or deep pain Total Median: No cuff 23.9 21.7 49.1 46.7 27.1 100.1 100. 1 218 120 Cuff 31.7 Ulnar: No cuff 31.4 24.1 38.7 47.2 29.9 28.6 100.0 99.9 328 199 Cuff Radial: No cuff 21.5 10.2 34.2 44.3 49.1 100.0 100.0 149 108 Cuff 40.7 Peroneal: No cuff 39.1 25.6 38.3 43.6 22.7 30.8 100.1 100.0 128 39 Cuff Tibial: No cuff 50.0 25.0 38.9 52.8 11.1 100.0 100.0 72 36 Cuff 22.2 Sciatic-peroneal : No cuff 55.1 45.0 37.0 39.0 7.9 16.0 100.0 100.0 127 100 Cuff Sciatic-tibia!: No cuff 59.0 49.3 35.0 36.0 6.0 14.7 100.0 100.0 100 Cuff 75 11. Use of Stay Suture Among all complete sutures, 67 percent were performed without resort to the stay suture, 22 percent with the stay suture, and in 11 percent the operation report was unclear or silent on the subject. As was noted in the roster-comparisons appearing in chapter II, stay sutures were much less often placed on sutures in the representative sample than on other sutures. To avoid this source of bias, therefore, the study of stay suture was confined to the representative sample of sutures, all of which are from the Army Registry and within the sampling area. Only the nerves of the upper extremity were studied, and the British summary of sensory recovery was used to provide the criterion. As may be seen in table 190, this limited study provides no evidence of any effect upon sensory return. 306

Table 189.—Percentage of Sutured Lesions With Superior Pain and Touch Thresholds1 in Relation to Use of Tantalum Cuff, by Nerve, for Lesions Selected *for Favorable Outcome Nerve sutured Number of lesions Percentage with superior pain thres- hold Percentage with superior touch threshold No cuff Cuff No Cuff P« No cuff Cuff P» cuff Median 11 21 33 18 10 10 19 17 27.3 29.0 26.1 11.1 20.0 16.0 23.1 57. 1 39.4 38.9 30.0 50.0 26.3 23.5 38.5 28.1 30.4 27.8 20.0 16.0 15.4 45.5 28. 1 61.1 27.3 50.0 15.8 23.5 Ulnar 31 23 18 10 25 26 Radial Peroneal Tibial Sciatic-peroneal Sciatic-tibial . . Total 144 128 22.2 38.3 <.01 24.5 34.9 .034 1 As defined in tables 186 and 187. 1 Having no associated injuries, short gaps, and moderate intervals from injury to suture. ' Probability obtained in statistical test of percentages. Table 190.—British Summary of Sensory Recovery and Use of Stay Suture at Definitive Suture, Nerves of the Upper Extremity Number of lesions Percentage with superior sensory return l Nerve Stay suture Median None 217 30.4 Any . 49 34.7 Total 266 31.2 Ulnar 360 30.0 77 28.6 Total 437 29.7 Radial None 169 55.0 Anv 52 42.3 Total 221 52. 1 1 Defined as groups 5, 6* and 7 in table 169, i. e., at least return of superficial pain and touch without overresponse. 307

12. Training of Surgeon Trained neurosurgeons performed about 45 percent of the definitive operations, general surgeons with wartime training in neurosurgery about 33 percent, and surgeons with essentially no special neurosurgical training the remaining 22 percent. The analysis of variation in sensory recovery associated with these differentials in neurosurgical training was done on pure lesions managed by complete suture. Pain recovery, touch recovery, and the British summary of sensory recovery were all employed as measures of functional sensory return, but for none of them was any evidence found that neurosurgical training, thus defined, was associated with differentials in sensory recovery. Table 191 presents a summary of the pain data to exemplify this analysis. Table 191.—Neurosurgical Training and Recovery of Pain Response in Autonomous %one Following Definitive Suture on Pure Nerve Lesions, by Nerve Neurosurgical training Nerve Trained neuro- surgeon General surgeon with neurosur- gical training Essentially un- trained in neurosurgery Statis- tical tests' Number of cases Percentage with pain thresholds of 10 grn. or less ' Number of cases Percentage with pain thresholds of 10 gm. or less ' Number of cases Percentage with pain thresholds of 10 gm. or less * Median 73 129 56 37 30.1 27.9 33.9 29.7 53 150 54 36 47.2 33.3 35.2 25.0 51 100 32 27.5 36.0 25.0 29.4 NS NS NS NS Ulnar Peroneal Tibial 17 1 Among all examined cases, including those classified as "hypesthesia, unmeasured." 1 Results of statistical tests (two-tailed) abbreviated as follows: NS=Not significant. 13. Summary Despite the difficulties inherent in arguing from the fact ol group dif- ferences to the effect of specific forms of treatment when treatment groups are defined by clinical considerations alone, sensory recovery at follow-up has been used as a criterion for exploring the possible influence of the variety of details on treatment abstracted from operation reports in military records of treatment. In general the results obtained here differ greatly from those presented in the motor chapter, so much so in fact that the difficulty is not one of interpreting variation in the light of treatment 308

differences but rather one of determining whether the observed variation is within the limits of a random process. The following characteristics appear not to be associated with significant variation in sensory recovery: Days from injury to definitive suture. Echelon (Z/I or overseas) of definitive suture. Length of surgical gap at definitive suture. Resort to bulb suture as a preliminary procedure prior to definitive suture. Operator's gross evaluation of nerve ends after freshening. Operator's report of tension on definitive suture-line. Suture material. Use of stay suture. Level of formal neurosurgical training of operator. In marked contrast to the analysis of motor recovery, it is extremely significant that the analysis here yields no evidence that time from injury to suture influenced sensory recovery in any way. The only elements of surgical treatment which were found to be asso- ciated with variation in sensory recovery, by the criterion of statistical significance used here, are: a. Transposition and mobilization of nerves in the lower extremity were followed by considerably poorer recovery of touch sensibility, but appeared to have no effect upon recovery of pain. In the upper extremity no such variation was seen. b. Sutured nerves about which tantalum foil cuffs were placed appear to have definitely superior recovery of both pain and touch sensibility, even after some effort at insuring the inherent comparability of the treatment groups in the light of factors present at suture which might be considered to have prognostic value. 309

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Peripheral Nerve Regeneration: A Follow-Up Study of 3,656 World War II Injuries Get This Book
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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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