Interfascicular neurolysis in chronic ulnar nerve lesions at the elbow: an electrophysiological study.

Interfascicular neurolysis of the ulnar nerve at the elbow was performed in nine consecutive patients with moderate to severe ulnar palsy. Sensory and motor conduction velocities were determined before and up to six times after the operation, and a follow-up period of three years or more in all but two patients. None of the patients recovered after the operation, and all developed severe and sometimes persistent paraesthesiae. Electrophysiologically there was no evidence of improvement immediately following the operation. On the contrary in some patients there were changes suggesting deterioration. At the final investigation most electrophysiological parameters were still abnormal. The only significant change was an increase in the amplitude of sensory action potentials at the wrist and just below the elbow. Only one patient showed a more synchronised sensory potential after operation. It is our conclusion that interfascicular neurolysis of the ulnar nerve should be abandoned.