Proximal humerus exposure with the inverted-L anterolateral deltoid flip approach, anterolateral deltoid splitting approach, and deltopectoral approach: A comparative cadaveric study.

Background: Reduction of the posterior aspect of proximal humerus fracture, such as far-retracted greater tuberosity or posterior articular head split fracture via a deltopectoral or deltoid splitting approach, is difficult and usually needs extensive dissection. The inverted-L anterolateral deltoid flip approach, which is developed from the deltoid splitting approach, accesses the proximal humerus via lateral deltoid flap lifting. This study compared the area and arc of surgical exposure to the proximal humerus of this proposed approach to existing approaches.

Methods: Eleven cadaveric specimens were used. Deltopectoral and deltoid splitting approaches were carried out on the right and left shoulder, respectively. Soft tissue was retracted after completion of a surgical approach to expose the proximal humerus, and dot-to-dot marking pins were placed along the border of exposed area. An additional area with a full shoulder rotation was also marked on the deltopectoral side. An inverted-L deltoid flip approach was further carried out on a deltoid splitting side with a posterior extending incision along the acromion process and the deltoid detachment from the acromion process. The additional area of exposure was subsequently marked. All soft tissue around the proximal humerus was taken down, and the glenohumeral joint was disarticulated. Area of exposure and axial images were taken for further processing and measurement.

Result: An average distance of the axillary nerve from the acromion process of the deltoid splitting and the deltopectoral approaches were 49.15 mm and 57.35 mm, respectively (P < 0.05). The average area of exposure of the inverted-L deltoid flip, deltoid-splitting, deltopectoral, and deltopectoral with full rotation approaches were 2729.81mm, 1404.39mm, 1325.41mm, and 2354.78mm, respectively (P < 0.05). Mean arc of exposure lateral to bicipital groove of the inverted-L deltoid flip, deltoid splitting, deltopectoral, and deltopectoral with full rotation approaches were 151.75degrees, 105.02degrees, 61.68°, and 110.64°, respectively (P < 0.05).

Conclusion: The inverted-L anterolateral deltoid flip approach provides the most posterior access to the proximal humerus. However, it requires more soft tissue dissection and awareness of tension on the axillary nerve. This approach could be an alternative for displaced posterior head splits or far-retracted greater tuberosity proximal humerus fractures.