The emergency nature of the incidents that cause spinal cord injuries, the heterogeneity of the resulting injuries and functional limitations, the longitudinal time course, the absence of standardized outcome measures, and the diverse community and the small number of individuals who receive such injuries all contribute to unique challenges in designing and conducting clinical trials of interventions for the treatment of spinal cord injuries.
Immediately after a spinal cord injury the body triggers a cascade of responses that can further injure the spinal cord and cause additional complications (see Chapter 2). Many of these changes occur within the first few hours after the injury. For a treatment to be effective at preventing the majority of the complications that arise during the acute stage of the injury, it must be provided to a patient soon after the injury; this period of time is generally thought to be 8 hours (Clifton et al., 2002).
To ensure that a patient is fully aware of the potential benefits and hazards of participating in a clinical trial, federal regulations require that patients provide informed consent before the experimental treatment is initiated. For patients who do not have the capacity to give informed consent, legal proxy can be obtained from a family member or a guardian. Therefore, obtaining informed consent for most clinical trials that examine interventions in the chronic stage of spinal cord injury has not been a major hurdle. However, experimental interventions are being developed that will require clinical trials involving patients in an emergency setting who may be unable to provide informed consent.
However, obtaining informed consent in emergency-care situations has been fraught with challenges. In many cases, interventions need to be administered as soon as possible after the injury and there is no time to wait for a patient to recover sufficiently or for a legal proxy to be obtained (Smithline and Gerstle, 1998). In 1996, revisions to the federal informed-consent regulations were made to allow a limited waiver for informed consent in the case of clinical trials of emergency-care interventions or other similar situations (DHHS, 1996; Smithline and Gerstle, 1998; Clifton et al., 2002). The previous regulations allowed for a waiver of informed consent only if the patient would receive no more than a minimal additional risk by entering into the trial. In the new language, the definition of the risk of the research was changed to “reasonable in relation to what is known about the medical condition of the potential class of subjects” (DHHS, 1996).