Adult Reconstruction, 1st Edition

Section III - Shoulder Reconstruction

Part B - Evaluation and Treatment of Shoulder Disorders

30

Surgical Exposures of the Shoulder

John-Erik Bell

Sara L. Edwards

Theodore A. Blaine

Patient Positioning

Shoulder surgery is typically performed in either a beach-chair or lateral decubitus position. In the beach-chair position, the head of the bed is elevated approximately 60 degrees. It is lowered if a concealed axillary approach is planned. The patient is shifted to the ipsilateral side of the bed, allowing the arm to be put through a full range of motion without coming into contact with the table. The head and neck are placed in neutral position and secured with tape to the head holder. A short arm board is placed on the table just above the elbow, which can be supplemented after draping by a sterile bolster. A hydraulic arm positioner can also be used as an alternative to the short arm board. For the posterior approaches, the patient is typically placed in a lateral decubitus position.

Skin Incisions

It is very important to take care to make the incision as cosmetically acceptable as possible. Although the most cosmetically acceptable incisions follow the Langer skin tension lines, it is also important to keep in mind sensory dermatomes to avoid neuromas and hypesthetic areas. Supraclavicular nerves supply sensation to the superoanterior shoulder, the axillary nerve supplies skin over the middle deltoid, and the posterior rami of cervicothoracic spinal nerves supply posterior skin from trapezius to scapula. The vascularity of the shoulder area is excellent, so flap viability is high despite extensive undermining in the plane of the deep muscle fascia. Small incisions also afford a great deal of exposure owing to the mobility of the shoulder joint, since seemingly hidden pathology can often be brought into view simply by rotating the arm.

Deltopectoral Approach

Standard Deltopectoral Approach

The standard deltopectoral approach is the workhorse for shoulder reconstruction (Fig. 30-1). It exploits the internervous plane between the axillary (deltoid) and medial/lateral pectoral nerves (pectoralis major). The standard incision is made from just inferior to the clavicle, over the coracoid process, extending down the arm to the area of the deltoid insertion in an oblique fashion. Needle-tipped electrocautery is used to create full-thickness flaps medially and laterally. This dissection extends superiorly to the clavicle and inferiorly to the insertion of pectoralis major. Two Gelpi retractors are placed in the superior and inferior aspects of the wound. The deltopectoral interval is then identified. It is typically highlighted by a stripe of fat overlying the cephalic vein, which should be carefully preserved. It is most convenient to retract the vein laterally with the deltoid, because there are fewer venous tributaries from the pectoralis than from the deltoid. Once the vein is freed from the pectoralis and hemostasis is achieved, the subdeltoid space is identified. The easiest way to identify this interval accurately is to begin in the subacromial space and sweep laterally and distally. A Richardson retractor is then placed beneath the deltoid, and the pectoralis tendon is identified.

In shoulders with limited external rotation, the proximal 5 to 10 mm of the pectoralis tendon may require release but should be repaired at the end of the case. Care should be taken when releasing the pectoralis tendon to avoid injury to the long head of biceps tendon running immediately laterally. A second Richardson retractor is then placed deep to the pectoralis muscle, revealing the clavipectoral fascia. This fascia is then incised just lateral to the conjoint tendon, and a medium Richardson retractor is placed to retract the conjoint tendon medially. Whereas both the short head of biceps and coracobrachialis are tendinous proximally, at the distal portion

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of the wound the short head of biceps muscle belly lies medial to the tendon of coracobrachialis, so, as the medium Richardson retractor is placed, care should be taken to avoid placing it in the interval between the short head of biceps muscle belly and coracobrachialis. With the conjoint tendon retracted medially, the coracoid and the coracoacromial ligament are identified. Ideally, the coracoacromial ligament should be preserved because it is an important part of the coracoacromial arch, but occasionally the leading edge must be released to facilitate superior exposure. A Darrach retractor is then placed beneath the deltoid and used to gently lever the humeral head anteriorly. The anterior bursa is completely removed, affording clear visualization of the subscapularis.

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The rotator interval is then identified, which demarcates the upper border of the subscapularis, and the lower border is recognized by the adjacent leash of vessels. These vessels are controlled with cautery or ligation. Many options exist regarding treatment of the subscapularis. The subscapularis can be removed from the humerus directly from bone, beginning just medial to the biceps tendon, which is advantageous if there is significant stiffness and loss of external rotation, since the subscapularis can be repaired back to bone more medially. The subscapularis tendon can also be divided 1 cm medial to its insertion, or a thin osteotomy of the lesser tuberosity can be performed, leaving the subscapularis attached to the bony fragment. The arthrotomy is continued superiorly through the rotator interval. Care must be taken to protect the axillary nerve and posterior circumflex humeral artery, which run under the muscular portion of the subscapularis toward the quadrangular space.

Concealed Axillary Incision

A variation on the standard deltopectoral approach is the concealed axillary incision (Fig. 30-2). This can be used for shoulder arthroplasty or for anterior stabilization procedures. Here, the incision strictly follows the Langer lines. Whereas the traditional deltopectoral approach is approximately 15 cm in length, the concealed axillary incision begins 3 to 5 cm inferior to the coracoid and extends only 5 to 7 cm into the axillary crease. Skin flaps are widely elevated, and the deltopectoral interval is identified. The rest of the approach is the same as in the deltopectoral. This approach may not give sufficient exposure of the tuberosities for large rotator cuff tears or for fracture cases.

Mini-Incision Approach

Current shoulder arthroplasty instrumentation usually exits the skin in a 5-cm arc centered just lateral to the coracoid process. In addition, the average diameter of the humeral head at the surgical neck is 49 mm. These facts suggest that the minimum incision length for shoulder arthroplasty is at least 5 cm. A 5-cm incision centered just lateral to the coracoid process can be used in shoulder arthroplasty and allows better access to the tuberosities for fracture cases than the concealed axillary incision. Again, wide subcutaneous flaps are created and the deltopectoral interval is identified. The cephalic vein is retracted laterally with the deltoid muscle. The remainder of the exposure is similar to the standard deltopectoral approach. Since glenoid exposure is often difficult even with traditional incisions, minimally invasive approaches should be reserved for only select patient populations. It is most appropriate for thin patients with good range of motion.

Extensile Deltopectoral Approach

For revision shoulder surgery, the exposure sometimes needs to be more extensile than the standard deltopectoral approach. The deltopectoral approach is extended distally by extending the incision along the lateral border of the biceps. The interval between biceps and brachialis is identified, and the biceps is retracted medially. Because the brachialis has dual innervation, it can be split longitudinally along its midline. The periosteum is then split, and subperiosteal dissection allows safe exposure of the humeral shaft. The radial nerve pierces the intermuscular septum 10 cm proximal to the lateral epicondyle of the humerus.

Anterosuperior Approach

Standard Anterosuperior Approach

This approach is used for the repair of a massive rotator cuff tear and can also be used for shoulder arthroplasty in the setting of a massive rotator cuff tear. The skin incision is made extending from the anterior lip of the acromion 8 cm distally in line with the deltoid fibers. Dissection is carried through subcutaneous tissue with cautery, and full-thickness flaps are raised anteriorly and posteriorly at the level of the superficial deltoid fascia. There is an avascular raphe separating the anterior and middle thirds of the deltoid, which is identified and incised from its acromial attachment distally to a point approximately 4 cm from the acromion. A stay suture is placed at the distal edge of the deltoid split to prevent propagation of the split beyond 5 cm, where the axillary nerve is known to lie. Richardson retractors are placed to retract the anterior deltoid anteriorly and the middle deltoid posteriorly. A complete bursectomy is then performed, allowing excellent exposure of the rotator cuff tear anatomy or, if the cuff is absent, the glenohumeral joint. Detachment of the deltoid origin from the lateral acromion is considered a last resort for increased exposure because of the postoperative complication of deltoid rupture, which is often not salvageable. If some fibers of deltoid origin are detached, it should be done strictly subperiosteally so that a cuff of stout tissue remains for repair.

Mini-Open Approach for Rotator Cuff Repair

The mini-open rotator cuff repair has been extensively studied and is considered an improvement over larger incisions that detach some of the deltoid origin. The approach consists of a 3- to 4-cm incision, which is often an extension of a previously placed midlateral arthroscopy portal. It is carried to the superficial deltoid fascia, above which full thickness flaps are elevated. The superficial deltoid fascia is then split in line with its fibers, again taking care to avoid propagating the split beyond 5 cm distal to the lateral edge of the acromion. The deltoid is then divided, exposing the subdeltoid/subacromial bursa. A bursectomy is performed, which allows excellent direct visualization of the rotator cuff, the anatomy of the cuff tear, and the cuff footprint on the greater tuberosity.

Combined Approach

For special cases, the advantages of both the deltopectoral and anterosuperior approaches can be exploited. This allows, in addition to the excellent deltopectoral exposure, visualization of the posterior glenohumeral joint and posterior cuff, especially the infraspinatus. If this approach is planned preoperatively, the standard deltopectoral skin incision is made slightly more laterally; otherwise, the combined

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approach can be done through the standard deltopectoral incision. Again, large full thickness flaps of skin are created and mobilized extensively. The deltopectoral approach is performed as described previously and then a second approach is made between the anterior and middle deltoid as described in the anterosuperior approach, but both approaches are made through the same deltopectoral incision.

Posterior Approach

Muscle-Sparing Approach

This approach is used for posterior instability and for fractures of the scapula and glenoid (Fig. 30-3). The patient is positioned in a lateral decubitus position, 60 degrees from

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prone. An incision is made vertically following the Langer lines along a line drawn from the posterolateral lip of the acromion to the posterior axillary fold, centered 2 cm beneath the acromion. Full-thickness flaps are raised at the level of the deep fascia. The deltoid as well as its superficial and deep fascia is split in line with its fibers. This deltoid split must not propagate beyond the teres major to avoid injury to the axillary nerve. The internervous plane between infraspinatus (suprascapular nerve) and teres minor (axillary nerve) is used for this approach. It is most easily identified at the medial aspect of the wound proximal to the musculotendinous junction and is often marked by a stripe of fat. It is important, however, that the dissection stays lateral to the glenoid neck to avoid injury to the suprascapular nerve. On entering the interval between infraspinatus and teres minor, the posterior joint capsule is apparent.

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Judet Approach

The Judet approach is a posterior approach used for complex posterior fracture patterns of the scapula and glenoid (Figure 30-4). The patient is positioned prone, and the skin incision begins at the posterolateral lip of the acromion, extends along the spine of the scapula, and turns at a right angle inferiorly along the medial border of the scapula. The posterior deltoid is elevated off the spine of the scapula. The underlying infraspinatus is elevated off the medial border of the scapula and retracted laterally on its suprascapular neurovascular pedicle, while care is taken to protect the pedicle.

Suggested Readings

Bigliani LU. Treatment of two- and three-part fractures of the proximal humerus. Instr Course Lect. 1989;39:231–244.

Brodsky JW, Tullos HS, Gartsman GM. Simplified posterior approach to the shoulder joint. A technical note. J Bone Joint Surg Am. 1987;69:773–774.

Henry AK. Extensile Exposure. 3rd ed. Edinburgh: Churchill-Livingstone; 1995.

Leslie JT, Ryan TJ. An anterior axillary incision to approach the shoulder joint. J Bone Joint Surg. 1962;44A:1193.

Neer CS. Anatomy of shoulder reconstruction. In: Neer, CS, ed. Shoulder Reconstruction. Philadelphia: WB Saunders: 1990;32–39.