Curved skin incision for ulnar nerve transposition in cubital tunnel syndrome: Cadaveric and clinical study to avoid injury of medial cutaneous nerve

Introduction: Medial skin incision is obligatory for ulnar nerve transposition in cubital tunnel syndrome. However, inadvertent surgical damage to the terminal branches of both the medial antebrachial cutaneous nerve (MACN) and the medial brachial cutaneous nerve (MBCN) has been a concern in the current surgical approach. Hypothesis: We hypothesized a modified curved skin incision to avoid the damage to the medial cutaneous nerve. Materials and methods: The numbers and locations of MACN and MBCN terminal branches were investigated; also, the location of the posterior branch of MACN in ten fresh frozen cadaveric upper extremities. Using modified incision which is more anterior than classic approach and includes antegrade dissection of the cutaneous branches, same measurement was performed in clinical cases. We described the techniques. Results: The average number of MACN posterior terminal branches was 2.6 ± 1.6 and 4.4 ± 2.4 branches in the cadaveric specimens and clinical cases, respectively. The average number of MBCN terminal branches was 2.1 ± 0.87 branches. The MACN posterior terminal branches were located at an average of 19 mm proximal and 45 mm distal from the medial epicondyle. In clinical cases, we could preserve all MBCN terminal branches and posterior terminal branches of MACN using the indexed skin incision. Discussion: Our modified medial skin incision technique with antegrade subcutaneous dissection exposed all the terminal branches of MACN and, thus, could reduce the risk of inadvertent injury. The medial epicondyle and the basilic vein are reliable anatomical landmarks to identify the posterior branch of the MACN. Level of proof: IV, cadaveric and therapeutic study.