Figure 5.

Illustrates the well-documented “funnel effect” for enrolling subjects to a clinical trial. The numbers are projections based on the incidence of SCI and cervical sensorimotor complete SCI within the United States. The numbers also reflect the incidence of SCI cases within a typical major US trauma center. The low levels of enrollment reflect the difficulties in acquiring adequate informed consent from an acute target population that has suffered a major traumatic injury (SCI). The difficulties are numerous and include the patient not being competent to understand the study protocol, as well as the risks and limitations of the trial procedures.