Spinal cord evoked potentials in cervical and thoracic myelopathy.

We have studied 70 patients who underwent surgical decompression with or without fusion for cervical and/or thoracic myelopathy to assess the value of spinal cord evoked potentials (SCEP). The 70 patients included 42 with cervical spondylotic myelopathy, 10 with ossification of the posterior longitudinal ligament of the cervical spine and 18 with thoracic ligamentous ossification. Abnormal SCEP occurred in 88% of the patients with cervical myelopathy. Early recovery in intra- and postoperative SCEP was associated with a better result. The severity of myelopathy correlated significantly with an abnormal SCEP in thoracic myelopathy. SCEP may reflect the severity of disease, and early recovery of intraoperative SCEP may also predict neurological improvement.