F-4-06-04
MOTOR EVOKED POTENTIALS AND MAGNETIC RESONANCE IMAGING FOR CERVICAL SPONDYLOSIS
O. KAMEYAMA, H. KAWAKITA, T. SUGA, R. OGAWA (Kansai Medical University, Osaka, Japan)
The outcome for cervical spondylosis treatment is occasionally disappointing in spite of adequate operation and rehabilitation. The purpose of this study is to elucidate usefulness of the motor evoked potentials (MEPs) and MRI for the prognostication of the treatment. Retrospectively we have studied the MEPs and the MRI image of 71 patients of cervical myelopathy. Before operation, the patients had the remarkable prolonged central motor conduction time. MRIs indicated the deformed spinal cord, and the signal intensity of the involved spinal cord in T2 image was remarkably high. The recovery rate of JOA score was correlated with the central motor conduction time and the signal intensity ratio in the involved area. The results showed that the high signal intensity in the T2 weighted image and the prolonged conduction time or absence of MEPs largely corresponded to the clinical and other investigative features of myelopathy.
F-4-06-05
SERIAL CHANGE OF SOMATOSENSORY EVOKED POTENTIALS IN CERVICAL MYELOPATHY AFTER SURGERY
Kenji Ishida, Hiroshi Yamamoto, Toshikazu Tani (Kochi Medical School, Kochi, Japan)
(Purpose) Sequential change of scalp-recorded somatosensory evoked potentials (SEPs) following median and tibial nerve stimulation were delineated during the postoperative course of recovery from myelopathic condition. The purpose of this study is to evaluate the type of SEP improvement in relation to the prognosis of myelopathy after surgery.
(Methods) Sixteen consecutive patients with cervical or thoracic spondylotic myelopathy were included in this study. The preoperative SEP recordings were succeeded by the serial recordings made in 2, 4, 8, 12, 16, 20 and 24 weeks following surgery. Clinical evaluations were assessed by the Japanese Orthopaedic Association (JOA) score.
(Result) The SEP improvement was detected in 14 out of 16 patients. The pattern of the serial SEP changes was divided into 3 types, early, intermediate and late recovery types. In 10 out of 14 patients, initially abnormal SEP began to improve as early as 2 weeks after surgery. In two patients, the SEP improvement was first detected between the 4th and 8th postoperative weeks. In remaining two patients, the SEP improvement appeared later than 8 weeks. The recovery rates of the early recovery type and the other type were 81.2% and 52.7% respectively.
(Conclusion) The type of SEP improvement appears to be an important indicator for predicting the prognosis of myelopathy after surgery.
