Submuscular transposition of the ulnar nerve: review of safety, efficacy and correlation with neurophysiological outcome

Summary Objective: The surgical management of ulnar nerve entrapment at the elbow is a controversial topic, with each surgeon believing his/her technique to be the best. The authors routinely perform submuscular transposition (SMT) of the ulnar nerve to treat entrapment neuropathy at the elbow. The aims of this review are (1) to review the results of SMT with respect to safety and complications, (2) to compare the efficacy of SMT with other studies previously published, and (3) to compare the clinical results with the neurophysiological outcome. Methods: A retrospective review of patients who underwent SMT for ulnar nerve entrapment between April 2000 and May 2003 was performed. Forty-five ulnar nerves in 44 patients were operated, of which 40 nerves were first time operation (primary group), and 5 nerves had previously undergone a simple decompressive procedure elsewhere (redo group). All patients were graded using the Louisiana State University Medical Centre (LSUMC) system for grading of ulnar nerve entrapment. Pre- and post-operative nerve conduction studies were performed, and these results compared to clinical recovery post-operatively. Results: For the primary group, function improved by one grade in 32.5%, two grades in 37.5% and three grades in 12.5% of patients. There was no change in 17.5%, and no patient deteriorated post-operatively. In the redo group there was improvement of at least one grade in 60% of patients. When clinical improvement was compared with electrophysiological improvement, no clear correlation was demonstrated. Conclusion: Submuscular transposition of the ulnar nerve is a safe, effective treatment for ulnar nerve entrapment at the elbow. When performed by trained peripheral nerve surgeons, good results are achievable for both primary and redo surgery.