A Study on Somatosensory Evoked Potential in Patients with Cervical Spondylosis

ABSTRACT

In order to study the relationship between clinical group of cervical spondylosis and electrical activity, we traced somatosensory evoked potential(SSEP) by stimulating the median nerve(MN) from the upper extremities, and the posterior tibial nerve(PTN) from the lower extremities simultaneously. The purpose of this study was to test the clinical diagnostic utility of the method, whether any consistent relationship exists between the severity and type of neurological symptoms and the results of the SSEP responses, and between neurological improved patients after operation and improved SSEP results. In this study patients were clinically divided into three groups combined myelopathy and radiculopathy, myelopathy alone, radiculopathy alone. Over a 3-year period from 1987 to 1989, SSEP were performed on 112 patients of Korean adults and summary of the results obtained are as follows 1) Among patients with cervical spondylosis, those with cervical myelopathy showed more abnormal SSEP than those cervical radiculopathy. 2) In the group with myelopathy, MN-cervical latensy, Ep-C2 interpeak latency. PTN-P1 latency, and N1 latency were prolonged more than MN-C2 latency, Ep-C2 interpeak latency, PTN-P1 latency, and N1 latency of the group with radiculopathy. 3) The longer the duration of the symptoms, the more abnormal were the SSEP in patients with cervical spondylosis. 4) In patient with cervical myelopathy, the latency of SSEP was prolonged not only in those with sensory deficit, but also with motor deficit. 5) Half of clinically improved patients after operation showed improved SSEP in follow-up examinations. 6) Improvement in SSEP after operation was much affected by posterior approach.