Minimally invasive application of the non-contact-bridging (NCB) plate to the proximal humerus: An anatomical study

Objectives: To describe a minimal anterolateral acromial approach for minimally invasive (MI) treatment of fractures of the proximal humerus (PH) with the Non-Contact-Bridging (NCB) plate. Design: 1) Cadaver study and 2) clinical case series. Setting: 1) University Institute of Anatomy and the 2) University Level I trauma center. Specimens/Patients: 1) Ten fresh frozen human humeri and 2) 22 patients with 22 isolated proximal humeral fractures. Intervention: 1) Minimal anterolateral acromial approach with MI application of the NCB-PH plate followed by dissection of the axillary nerve and 2) MI fracture fixation using this approach and technique of plate insertion. Main Outcome Measures: 1) Integrity of the axillary nerve and evaluation of its relationship to the implant, and 2) early postoperative functional results. Results: In the cadaver study, the nerve directly crossed over the percutaneously inserted plate in all the arms. The nerve then divided into two branches anterior to the plate in eight arms and divided into two branches directly over the plate in two arms. One branch of the axillary nerve in one arm was injured. In the clinical case series, no intraoperative complications relating to the approach or the implant occurred. No symptoms of axillary nerve lesion have been detected so far in the early follow-up. Conclusions The minimal anterolateral acromial approach is suitable for MI technique to apply the NCB-PH. The relationship of the axillary nerve to the plate is anatomically close. We recommend that strict bone contact be maintained during plate insertion and that screw insertion complies with the guidelines provided for this technique. In a small clinical cases series, the plate and screws were inserted in accordance with these guidelines and no axillary nerve lesions have yet been detected.