Neurophysiologic investigation of patients with spinal stenosis.

To study the role of neurographic, electromyographic, and psychophysic examinations when diagnosing spinal stenosis, the authors studied 64 patients (mean age, 64 years) with myelographically verified spinal stenosis. Sixteen patients showed signs of total occlusion of the dural sack. Twenty-four patients with spinal claudication but with normal myelograms constituted a comparison group (mean age, 57 years). Normal reference values were obtained from 50 men aged 28-63 years. In spinal stenosis with total occlusion, bilateral neurogenic changes were registered in 87.5%, without total occlusion in 81%, and in spinal claudication with a myelogram of normal width in 29%. The corresponding frequencies of multisegmental EMG abnormalities were 94%, 75%, and 21%, respectively. Motor conduction velocity was normal in spinal stenosis except in cases with total occlusion. High thresholds were found to vibration and temperature changes in the legs, much like in patients with polyneuropathy. However, polyneuropathy was found in only a minority of the patients.