Spinal cord evoked potential monitoring for cervical and thoracic compressive myelopathy.

Spinal cord evoked potentials (SCEPs) were recorded epidurally in 95 surgical cases of cervical and/or thoracic compressive myelopathy. Abnormal SCEPs occurred in 91% of the patients with cervical myelopathy and in all with thoracic involvement at the levels suspected to be responsible for neurological damage. Abnormal SCEPs correlated significantly with the severity of spinal cord compromise and symptoms, such as myelopathy. It was not possible to predict postoperative neurological improvement on the basis of the preoperative SCEP findings alone, but better neurological improvement after surgery was closely associated with early recovery of intra- and postoperative SCEPs. Epidural SCEPs are therefore useful in making a level-specific diagnosis, especially in the patient with multilevel vertebral involvement, and in assessing the severity of neurological compromise and surgical outcome to some extent.