Complete Removal of the Epitrochleoanconeus Muscles in Patients with Cubital Tunnel Syndrome: Results From a Small Prospective Case Series.

BACKGROUND: Sometimes during surgery for cubital syndrome an anomalous muscle called the epitrochleoanconeus is encountered. Different surgical strategies on how to decompress the ulnar nerve in the presence of this muscle have been proposed, including transection of the muscle, resection, or subcutaneous transposition of the ulnar nerve. Because of the low incidence, there is no consensus on what type of surgical treatment can best be performed. In the present study, we prospectively followed a small series of patients, in which the muscle was resected.

METHODS: Five patients who presented to our clinic with cubital tunnel syndrome in the presence of an epitrochleoanconeus muscle were followed prospectively. Two patients had bilateral epitrochleoanconeus muscles, 1 patient had recurrent symptoms after previous myotomy. Clinical outcome after resection of the muscle was graded using the Likert scale. In addition, histopathologic analysis was performed on the resected muscles, including ATPase histochemistry.

RESULTS: Six of 7 cases had complete relief of symptoms (Likert 1) 6 weeks after excision of the epitrochleoanconeus muscle, including the case with recurrent symptoms after previous myotomy. Histopathologic analysis of the muscles showed grouped muscle fiber atrophy and type grouping in all cases, both signs of denervation that confirm the compressive pathophysiology of cubital tunnel syndrome in these patients.

CONCLUSIONS: The results of this small prospective case series show that excision of the epitrochleoanconeus muscle in patients with cubital tunnel syndrome frequently leads to complete recovery. Further support for this surgical strategy was found from histopathologic analysis of the resected muscles.