Spinal Cord Injury

Neonatal spinal cord injury may occur as an obstet­rical complication or as a result of a vascular insult to the spinal cord. Typical clinical presentation may include findings of diffuse hypotonia, possible respira­tory distress, hyporeflexia, and urinary retention.

Traumatic spinal cord injury often results in loss of anterior horn cells at a specific “zone of injury.” For example, a child with C5 tetraplegia may have denervation present at the bilateral C6 and C7 myo­tomes. This zone of partial or complete denervation becomes particularly relevant in the evaluation of a patient for possible placement of an implanted func­tional electrical stimulation system for provision of voluntary grasp and release. Presence of denervation necessitates concomitant tendon transfers with electri­cal stimulation of the transferred muscle group.

SSEPs may help establish a sensory level in an infant or young child with spinal cord injury, and is also useful in the evaluation of the comatose or obtunded child at risk for spinal cord injury without radiographic abnormality (SCIWORA). Somatosensory evoked potentials are discussed in a following section.

Transcranial electric motor evoked potentials (MEPs) to monitor the corticospinal motor tracts directly are now used routinely in addition to SSEPs for detection of emerging spinal cord injury during surgery to correct spine deformity or resect intramed­ullary tumors (54-56). Afferent neurophysiological signals can provide only indirect evidence of injury to the motor tracts since they monitor posterior column function. Transcranial electric motor evoked potentials are exquisitely sensitive to altered spinal cord blood flow due to either hypotension or a vascular insult. Moreover, changes in transcranial electric MEPs are detected earlier than are changes in SSEPs, thereby facilitating more rapid identification of impending spi­nal cord injury.