Somatosensory evoked response evaluation of cervical spondylytic myelopathy.

There were 13 patients with cervical spondylytic myelopathy (CSM) evaluated. All had extradural defects with distortion of the cervical cord and partial or complete obstruction of myelographic dye. Posterior tibial scalp (SSEPs) were absent or delayed in all 13, whereas median SSEPs were abnormal in 9. Median SSEP abnormalties were limited to those with cord lesions at C5-C6 or above. There were eight patients with associated radiculopathies confirmed by electromyography. No meaningful differences in SSEPs were noted between those with or without root injury. Surgery confirmed the level of cord injury in 10. CSM is common with a high morbidity. The results indicate SSEPs using leg stimulation can be a sensitive indicator of cord injury in these patients and that the more commonly used arm stimulation is of value primarily for localizing the level of the myelopathy.