Postoperative compression and regeneration following ulnar nerve transposition

: In 58 patients with sulcus ulnaris syndrome the ulnar nerve was transposed intermuscularly under the ulnar flexor muscles. All the patients were examined after the operation clinically and electrophysiologically for recognizing the grade of postoperative regeneration and the possibility of a new compression. 86% postoperatively showed a good functional result. Electrophysiologically there was often found no normal duration and amplitude of the muscle action potential. 2 Patients showed symptoms of a postoperative compression of the transposed ulnar nerve under the origin of the ulnar flexor muscles. In order to avoid this complication the divided muscles must not be reunited with the medial epicondyle. Bad results after intermuscular transposition of the ulnar nerve are explained neither by a new compression nor by an unsatisfying regeneration of the nerve. They are the consequence of wrong diagnosis, common nerve lesion or fibrosis of muscle. A comparison with the results of other authers demonstrates that an additional interfascicular neurolysis is not necessary. The deep transposition of the ulnar nerve is recommended as the method of choice.