CHAPTER 26 Surgical Approach
Two surgical approaches have been described for implantation of a reverse prosthesis. The anterior superior approach was initially used because it makes use of the rotator cuff defect. More recently, the deltopectoral approach has been used for insertion of a reverse prosthesis. We perform all reverse prostheses through the deltopectoral approach, which is our preferred approach for five reasons:
1. Deltoid violation A reverse prosthesis relies on the deltoid muscle to power elevation of the arm. The anterior superior approach violates the deltoid muscle, which may be a problem.
2. Level of humeral resection Glenoid exposure when using the anterior superior approach may require more resection of the proximal humerus than when using the deltopectoral approach. During the anterior superior approach, the humerus is retracted inferiorly to obtain access to the glenoid. If glenoid exposure is inadequate after appropriate soft tissue release, the only solution to enhance glenoid exposure is resection of more of the proximal humerus. More bone resection may make proper deltoid tensioning difficult and lead to weakness in elevation.
3. Glenoid component positioning It is generally agreed that the reverse glenoid component should be placed inferiorly on the glenoid face to help prevent impingement of the humeral component on the scapula and subsequent scapular notching. The need to retract the humerus inferiorly to access the glenoid with the anterior superior approach creates more difficulty in getting the glenoid component aligned with the inferior aspect of the glenoid face. Debate exists on whether inferior tilt should be introduced during glenoid reaming so that the glenoid component is positioned to better avoid scapular notching. However, it is agreed that superior tilt should be avoided. Using the anterior superior approach risks inadvertently placing the glenoid component in a superiorly tilted position, which risks glenoid failure (Fig. 26-1).
4. Extensile exposure The deltopectoral approach can easily be extended into an anterolateral approach to the humerus, whereas the axillary nerve limits distal extension of the anterior superior approach. Review of a consecutive series of 100 reverse prostheses performed at Texas Orthopedic Hospital demonstrated that the underlying etiology necessitated a more extensile exposure than what could be obtained with an anterior superior approach in 36 cases (18 nonunion/malunion, 17 revision, 1 fixed dislocation requiring anterior glenoid reconstruction with iliac crest autograft).