Anterior minimally invasive plating osteosynthesis technique (MIPO) for humeral shaft fractures: an anatomical study of neuromuscular structures at risk

OBJECTIVE The aim of this study was to evaluate the neuromuscular structures at risk during modified anterior minimally invasive plating osteosynthesis technique (Belangero-Livani) for humeral shaft fractures. METHODS Eight fresh-frozen human specimens ranging from 38 to 82 years old were used. Specimens were positioned supine with the shoulder in 70° abduction and the forearm in full supination. Anterior minimally invasive plating osteosynthesis technique according to Belangero-Livani technique was performed in each specimen. Under radioscopic control, the plate was introduced in retrograde fashion through the subbrachialis path. Anatomical structures were inspected and different anatomical parameters were measured after dissection at the end of the surgical procedures. Measurements were performed using a high digital caliper. Statistical analysis was performed using the Pearson's correlation coefficient test. A p value of < 0.05 was used to define statistical significance. RESULTS There were no macroscopic lesions of myotendinous or neurovascular structures in any specimen. The mean distance between the radial nerve to the distal lateral end of the plate was 8.63 mm (range 4.14-13.83 mm). The mean total length of the humerus was 328.59 mm. We found a significant direct correlation between the total length of the humerus and both specimen height and weight. CONCLUSION The modified Belangero-Livani anterior MIPO technique for humeral shaft fractures performed in retrograde fashion is safe and useful, without major risk to the soft tissue of the anterior compartment of the arm, including the radial nerve in the lateral intermuscular septum. Intraoperative dissection, avoiding deep lateral retraction on the distal approach, minimizes the risk of radial nerve damage. Strict surgical planning and appreciation for the anatomic landmarks can reduce the risk of damage to neuromuscular structures. LEVEL OF EVIDENCE Level IV; Case series with no comparison group; Treatment study.