Shoulder arthrodesis may alleviate pain and instability in a variety of patients. Although typically an end-stage procedure, common indications for shoulder arthrodesis include reconstruction after tumor resection, failed arthroplasty, brachial plexus injury, chronic infection, and refractory shoulder instability.1–3 The patient presented in this Supplemental Digital Content 1 (see Video, http://links.lww.com/JOT/A400) is a 25-year-old woman with Ehlers–Danlos syndrome who suffered from chronic left shoulder multidirectional instability. She had undergone 3 previous surgeries in attempts to stabilize the joint; however, the patient continued to suffer from pain and recurrent dislocations. After discussion with the patient, it was agreed that she fit indications for shoulder arthrodesis because of refractory instability.1,4–6
The patient is brought to the operating room and, following intubation, is placed in the right lateral decubitus position. As seen in Supplemental Digital Content 1 (see Video, http://links.lww.com/JOT/A400), the patient's left forequarter shoulder area is sterilely prepped and draped, with special attention to maintaining the ability to check the final positioning of the shoulder. The goal is to perform the arthrodesis with a shoulder position of 30 degrees of flexion, 30 degrees of abduction, and 30 degrees of internal rotation.7 A posterolateral approach to the shoulder is used, extending proximally over the scapular spine and distally over the posterolateral aspect of the humerus.5 An incision is made, and once dissected to the scapular spine proximally, the bone is followed distally to the attachment of the posterior deltoid. The axillary nerve is identified with its associated vessels. Ligation clips are applied and the nerve is transected with its vessels because the deltoid will no longer be functional with the shoulder joint being fused, although some advocate preserving the nerve to maintain the deltoid for shoulder contour.2 At this point, the lateral aspect of the acromion is osteotomized and reflected anteriorly to facilitate exposure. The posterior capsule is opened and the humeral head subsequently dislocated posteriorly. Once the shoulder is dislocated, the suprascapular nerve and associated vessels may be identified crossing the spinoglenoid notch. They are similarly ligated and transected, allowing for the mobilization of the rotator cuff muscles from the scapula for identification of bony anatomy, specifically the inferior aspect of the neck and glenoid. As seen in Supplemental Digital Content 1 (see Video, http://links.lww.com/JOT/A400), this identification allows for the procedure to be completed without the need for fluoroscopy.
An oscillating saw is used to create the bony cuts. The goal is to obtain both glenohumeral and subacromial fusion. First, a cut is made on the glenoid surface perpendicular to the axis of the glenoid, removing just enough to expose the bleeding subchondral bone. Next, the proximal humerus is cut to form a bony block. These humeral cuts are important in determining the final position of the shoulder. The superior cut is paramount to determining flexion and abduction position, whereas the medial cut has a major role in determining the rotational position of the joint. The greater tuberosity may be cut as well to allow for better lying of the plate on the bone. Once these cuts are made, the inferior aspect of the acromion is decorticated using a variety of instruments.1 A 4.5-mm dynamic compression plate is used for the fixation.1,2,8 Before being applied, the plate is contoured by providing some rotation, which avoids anterior humeral overhang of the plate, and bent to lie over both the humerus and the acromion. The goal is to provide adequate fixation and screw purchase so that only a sling is necessary postoperatively and no shoulder spica cast is needed. Typically, 4 screws in the scapular spine and 4 bicortical screws in the humerus achieve this, with additional screws to aid in compression and fusion. The first screw is placed from the plate through the scapular spine and glenoid and the second is placed from the plate through the humeral head and glenoid. Remaining screws are placed, with the bicortical humeral screws being placed in compression.
Once fixation is achieved, the glenohumeral and subchondral regions have been compressed, and any gaps may be filled with autologous bone from the previous cuts. The lateral aspect of the acromion maintains its vascularization as it was reflected forward previously, so it is then repaired to the plate using nonabsorbable suture to provide further bony coverage. The tissues are closed in layers, with attention to providing soft-tissue coverage to the hardware. At the conclusion of the video, functional motion is assessed by ranging the patient's elbow to ensure that she is able to reach her mouth with ease. Furthermore, in postoperative follow-up, the patient was also able to reach the top of her head and lumbar spine through scapulothoracic motion.
This video demonstrates the technique for performing a shoulder arthrodesis in a patient with refractory shoulder instability who had failed previous surgical treatments. Although alternative techniques are valid, the importance of adequate exposure and maintaining modern techniques for bony fusion are displayed in the video. The procedure shown may be applied to shoulder arthrodesis for a variety of indications.
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