Is an anteromedial minimally invasive approach for middle and distal third humeral fractures feasible? A cadaveric study and clinical case series

BACKGROUND: Iatrogenic injury to the radial nerve is a risk in surgical treatment for extraarticular fractures of the middle and distal third of the humerus. We aimed to investigate the safety, feasibility and advantages of minimally invasive percutaneous plate osteosynthesis (MIPPO) via an anteromedial approach in the treatment of middle and middle-distal humeral fractures and to evaluate proximity to neurovascular structures. MATERIALS AND METHODS: In 2016, 13 adult cadaver arms were used to simulate a minimally invasive surgical approach to the anteromedial humerus followed by fixation with a locking compression plate (LCP), and several sets of anatomical data were measured to clarify the possible risk of iatrogenic vascular and nerve injury in this surgical approach. Then, a case series study of 12 patients with humeral fractures who were treated with this surgical approach was conducted between 2017 and 2020. RESULTS: The average humeral length was 29.22 ± 1.62 cm, the average width of the medial epicondyle of the humerus was 1.31 ± 0.17 cm, and the average distance from the vertex of the medial epicondyle to the median nerve was 2.96 ± 1.62 cm. Furthermore, the safe area for distal humeral screw placement was 6.28 ± 0.39 cm, and the average distance from the tip of the distal end of the screw in the medial epicondyle to the ulnar nerve was 1.7 ± 1.25 mm. None of the 12 patients had nerve damage or an incisional infection after the operation. CONCLUSIONS: The new approach was performed as described, and no cases of iatrogenic nerve palsy occurred. This approach can be used as an alternative for the treatment of extraarticular fractures of the middle and distal thirds of the humerus. Level of Evidence: Level IV, therapeutic study.