Evoked Electromyographic Pre and Postoperative Assessment of Patients with Cervical Myelopathy

Abstract

Evoked electromyographic studies—especially repeating stimuli method of 10 cycles per second—of the M. gastrocnemius were done in 13 patients with myelopathy caused by cervical spondylosis, ossification of the posterior longitudinal ligements in cervical spinalcanal, or C4/C5 herniated disc.The following results were obtained.1) Of 13 patients, 2 patients could not induced the H waves.2) Remaining 11 patients had the H waves were divided 4 groups:Group 1-This group consisted of 4 patients with a high plateua level of the amplitude of the H waves following repeating stimuli.Group 2-This group consisted of 3 patients with a high plateua level and moreover many fluctuation of the H waves.Group 3-This group consisted of 2 patients with many flucutation of the H waves, that was more remarkable than group 2.Group 4-This group consisted of 2 patients with not only many fluctuation but also some slow undulation of the H waves.3) The authors investigated the relation between 4 groups and the clinical signs, electromyographic fiindings in the muscles of the lower extremities and absolute anteroposterior diameter of the cervical spinal canal in radiological examinations of the patients. Consequently it is likely that patients with group 1 may be indicated the anterior fusion of the level of the disc involvement, and patients with group 2 or 3 indicated the decompression of the spinal cord by the laminectomy.