V-Y Lengthening Technique of the Flexor-Pronator Mass for Anterior Submuscular Transposition of the Ulnar Nerve in Severe Cubital Tunnel Syndrome: A Long-Term Follow-Up Study.

Abstract

This study aimed to retrospectively analyze the clinical results of anterior submuscular transposition of the ulnar nerve using a flexor-pronator V-Y lengthening technique in patients with severe cubital tunnel syndrome (CTS). From January 2007 to May 2015, 36 patients with grade III CTS based on McGowan's classification were enrolled. All patients were treated with anterior submuscular transposition of the ulnar nerve using a flexor-pronator V-Y lengthening technique. To evaluate clinical outcomes, all patients underwent preoperative and final follow-up assessments of disabilities of the arm, shoulder, and hand scores, nerve conduction velocity, 2-point discrimination, and pinch and grip strength. Overall functional outcomes were evaluated after a mean follow-up of 53 months using the Modified Bishop rating system. We analyzed the statistical correlation of patients' duration of symptom and age with clinical results. At the final follow-up, the average disabilities of the arm, shoulder, and hand, nerve conduction velocity, 2-point discrimination, and grip and pinch strengths significantly improved in all patients. At least a 1-McGowan grade improvement was achieved in 34 extremities (94.4%). According to the modified Bishop scores, 30 patients (83.3%) achieved good or excellent outcomes and 2 extremities (5.5%) had poor outcomes. There was a significant negative correlation between prolonged symptom duration and the Modified Bishop score at the final follow-up, but age did not affect the functional outcome. In McGowan grade III severe CTS, anterior submuscular transposition of the ulnar nerve using a flexor-pronator V-Y lengthening technique leads to satisfactory outcomes. Longer symptom duration is associated with poorer results, and the outcome is not correlated with age. Therefore, active surgical treatment should be considered regardless of age before severe disease occurs.