Prevention of minimally invasive plate osteosynthesis (MIPO) complications in diaphyseal humerus fractures: a cadaveric topographic anatomical study

Background Minimally invasive plate osteosynthesis (MIPO) corresponds to the modern principles of "biological" fixation as it implies closed reduction and plate insertion causing minimal iatrogenic trauma. However, the lack of direct visualization increases the risk of damage to important anatomical structures. Purpose To develop recommendations in the use of MIPO for diaphyseal fractures of the humerus from anterolateral approaches to prevent possible complications and improve the results. Methods 16 shoulders of fresh cadavers were included in the study. In all cases, MIPO was performed with a straight plate (10-12 holes) and screws (2 proximal and 2 distal) using two anteriolateral approaches. Complete revision of the shoulder area was carried out in order to determine the accuracy of plate location and the relationship between the implant, neurovascular structures and bone landmarks. Results No damage or compression of the neurovascular and tendomuscular humerus structures was revealed. The average distance from the acromion to n. axillaris was 5.8 ± 0.66 mm (range from 4.9 to 6.9 mm). The average distance from the lateral epicondyle of the humerus to n. musculocutaneus was 56.5 ± 4.66 mm (from 49 to 63 mm). We observed the difference in location at the extreme pronation (5.1 ± 0.33 mm, from 4.5 to 5.7 mm) and supination positions of the forearm (5.8 ± 0.6 mm, from 5.1 to 6.1 mm) measuring the distance between the edge of the plate and n. radialis. The average distance between the distal medial edge of the plate and a. brachialis, n. medianus was 17.1 ± 2.7 mm (from 13 to 21 mm). Conclusions Based on the obtained data, we offer MIPO recommendations for anterolateral accesses in diaphyseal fractures of the humerus. Compliance with the proposed recommendations will reduce the risk of iatrogenic damage and improve the results of humeral fractures treatment.