Surgical Exposures of the Shoulder

Review Article

Surgical Exposures of the Shoulder Abstract Peter Nissen Chalmers, MD Geoff S. Van Thiel, MD, MBA Scott W. Trenhaile, MD

From Rush University Medical Center, Chicago, IL (Dr. Chalmers) and Rockford Orthopaedic Associates, Rockford, IL (Dr. Van Thiel and Dr. Trenhaile). Dr. Trenhaile or an immediate family member has received royalties from, is a member of a speakers’ bureau or has made paid presentations on behalf of, and serves as a paid consultant to Smith & Nephew; has received research or institutional support from Endo Pharmaceuticals; and serves as a board member, owner, officer, or committee member of the Arthroscopy Association of North America. Neither of the following authors nor any immediate family member has received anything of value from or has stock or stock options held in a commercial company or institution related directly or indirectly to the subject of this article: Dr. Chalmers and Dr. Van Thiel. J Am Acad Orthop Surg 2016;0:1-9 http://dx.doi.org/10.5435/ JAAOS-D-14-00342 Copyright 2016 by the American Academy of Orthopaedic Surgeons.

Surgical repair, reduction, fixation, and reconstruction for glenohumeral trauma, instability, and degenerative joint disease often require an open surgical exposure. Open shoulder surgery is challenging because the deltoid and rotator cuff musculature envelop the joint, and in most approaches, exposure is limited by the proximity and importance of the axillary nerve. An understanding of the importance of the deltoid and the rotator cuff for glenohumeral function has led to a progression of innovative, advanced, and less invasive approaches to the shoulder. Various advantages, disadvantages, and risks are encountered when performing deltopectoral, deltoidsplitting, and posterior approaches to the glenohumeral joint, with variations of each approach and techniques to extend them and maximize exposure. The ability to perform each of these exposures provides the surgeon with the flexibility to best address the widest variety of pathology.

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ince the introduction of open shoulder stabilization by Bankart and the popularization of shoulder hemiarthroplasty by Neer, open shoulder approaches have been performed with increasing frequency. As the population ages, increased numbers of patients are undergoing total shoulder arthroplasty (TSA), reverse total shoulder arthroplasty (RTSA),1 and open reduction and internal fixation (ORIF) of proximal humeral fractures (PHFs).2-4 Unique exposure challenges are encountered in the glenohumeral joint because of the range of motion, the close proximity of neurovascular structures, and the double envelopment of the joint by both the deltoid and the rotator cuff. These challenges have led to a profusion of techniques, of which three will be discussed in depth: the deltopectoral (DP) approach, the deltoid-splitting (DS) approach, and the posterior approach.

Anatomy and At-risk Neurovascular Structures The shoulder is enveloped by the deltoid and the rotator cuff. Surgical exposure of the glenohumeral joint is obtained by either splitting natural intervals between these structures or by releasing and reattaching these structures. The axillary nerve follows a path down the anterior subscapularis, traveling around the inferior border just 1 cm medial to the musculotendinous junction, and finally tracking posteriorly, where it lies roughly 1 cm from the inferior glenoid rim. Posteriorly, the nerve passes through the quadrilateral space before dividing into a posterior branch that innervates the teres minor and the skin over the lateral deltoid and an anterior branch that winds anteriorly deep to the deltoid, innervating all three heads. The anterior branch is typically located 5 to 7 cm distal to the lateral acromial edge. However, in 20% of patients, the

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Surgical Exposures of the Shoulder

Figure 1

the approach avoids scarring by following anatomic planes. The disadvantages of this approach include the inability to address posterior pathology and the need for subscapularis takedown.

Figure 2

Patient Positioning and Set-up Photograph demonstrating the modified beach-chair position.

Illustration of the deltopectoral approach viewed anteriorly, demonstrating the circuitous route of the axillary nerve. To perform the tug test (arrows), the right index finger is placed on the axillary nerve at the inferior subscapularis and the left index finger is placed on the axillary nerve on the undersurface of the deltoid.

branch is located ,5 cm from the lateral edge, with some cases measuring a distance of only 3 cm.5 Damage to this nerve deinnervates the deltoid and causes substantial shoulder dysfunction6 with essentially no surgical recourse.7 Intraoperatively, the continuity of the nerve may be tested with the tug test, in which the surgeon hooks the nerve at the anterior subscapularis and at the undersurface of the deltoid. A tug on one finger is then transmitted to the other finger using the humerus as a pulley8 (Figure 1). The brachial plexus and brachial artery are also at risk of injury with dissection medial to the conjoint tendon.

Historical Perspective Approaches to the glenohumeral joint have progressed from more invasive to less invasive. For example, shoulder stabilization has progressed

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from subscapularis tenotomy to subscapularis-splitting to the arthroscopic approach.9-12 Although the initial RTSA report by Grammont et al13 described a transacromial approach, 38% of patients required revision for nonunion. To avoid damaging the insertions of the rotator cuff and deltoid,1,14-16 which can be irreparable7 and severely disabling in terms of function,6 subsequent authors have described less invasive DP and DS approaches.1 Projecting this trend, surgeons are exploring arthroscopic approaches to the Latarjet procedure, posterior osseous augmentation of the glenoid, and biologic glenoid resurfacing.

Deltopectoral Approach The DP approach is the most commonly used approach to the shoulder and is indicated for shoulder hemiarthroplasty, TSA, RTSA, open shoulder stabilization, and ORIF of PHFs and anterior glenoid fractures.

Advantages and Disadvantages Surgeon familiarity with the DP approach and its extensile nature is among the advantages of the approach. In a prospective nonrandomized study by Hepp et al,17 the authors reported better Constant scores with ORIF for PHFs than with the DS approach at 1 year postoperatively, possibly because

We use a combination of regional anesthesia with an ultrasonographyguided interscalene or supraclavicular block and/or general anesthesia with the endotracheal tube exiting on the nonsurgical side. Both methods of regional anesthesia have been shown to be safe, with no permanent neurologic injuries in a series of .1,100 patients.18 Some surgeons are now using still-experimental variations in regional anesthetic techniques, such as long-acting liposomal bupivacaine or a sustained, continuous-release device paired with a catheter. We prefer to use a modified beachchair position with the back elevated to 45" and the thighs and knees flexed (Figure 2). Although clinical complications are rare with this position, it remains controversial because it may be associated with cerebral hypoperfusion in at-risk patients; therefore, prophylactic intraoperative neuromonitoring techniques are being investigated.19 The neck must remain in neutral alignment, with the head well-padded and firmly secured to avoid neurologic complications, such as stroke, traction brachial plexopathy, or posterior auricular neuropathy. Two surgical towels are then placed medial to the scapula to protract the scapula, antevert the glenoid, and provide counterpressure during reaming. Two lights, one at the head and one at the feet, should be focused on the incision. A third light, positioned laterally and low and pointed medially, is focused on the glenoid. Oblique positioning of the surgical table allows room for assistants to

Journal of the American Academy of Orthopaedic Surgeons


Peter Nissen Chalmers, MD, et al

Figure 3

Photograph of the surgical set-up after sterile prep and draping. The shoulder has been sealed with an adherent, iodinated drape, and a padded Mayo stand is shown for positioning. The surgical scrub is positioned on the ipsilateral side. Depending on the size and shape of the operating room, the scrub can also be positioned on the contralateral side, with the Mayo stand positioned over the patient’s body.

stand posterior and lateral to the shoulder. To alter and hold the position of the shoulder during surgery, the surgeon may use a padded Mayo stand, a trained assistant, and a movable short arm board; alternatively, a pneumatic, articulated arm holder may be used (Figure 3).

Incision and Dissection The DP incision is 10 to 12 cm in length and extends from the coracoid process toward the deltoid insertion parallel to the deltoid. To locate the split between the deltoid and the pectoralis major, a marking pen is rolled across the skin to locate the “valley” of the interval (Figure 4). Of note, this incision obliquely crosses the skin tension cleavage lines of Langer, thus potentially spreading and creating a cosmetically unappealing scar.20 After dissection through the wellvascularized subcutaneous adipose tissue, the surgeon locates a triangle of fat at the proximal aspect of the dissection that extends into an oblique stripe across the incision, under which the cephalic vein may be identified

Figure 4

Clinical photograph demonstrating rolling the marking pen in line with the deltoid to identify the valley that represents the natural cleavage line between the deltoid (curved arrow) and the pectoralis major (dashed arrow), which intersects the palpable tip of the coracoid (straight arrow).

(Figure 5). We prefer to perform dissection medial to the vein because there are fewer medial branches than there are lateral branches.21 Proximally, brisk bleeding may be encountered at the deltoid and acromial branches of the thoracoacromial trunk. In revision situations, the cephalic vein and the nonabsorbable suture placed during the prior closure can provide guidance. Another alternative in revision situations is to dissect distally to the lateral aspect of the subscapularis tendon and to elevate all muscle lateral to this attachment off the humerus. Correct identification of the interval is critical because creation of a nonanatomic split within the anterior deltoid can deinnervate a portion of the anterior deltoid, thus limiting postoperative flexion strength. The subacromial and subdeltoid spaces are then opened bluntly in a controlled manner to achieve hemostasis. In revision situations, any stout subdeltoid adhesions that have formed must be released. To avoid injury to the posterior circumflex humeral artery, caution should be employed to avoid overzealous dissection of subdeltoid adhesions. Bursal material must be removed to visualize the rotator cuff. In

Figure 5

Intraoperative photograph demonstrating the cephalic vein (white arrows) in the deltopectoral interval (dotted line). The deltoid has begun to unfurl as a result of partial dissection of the interval.

virgin tissue, rotation of the arm allows the surgeon to discern the rotator cuff from bursal tissue; tissue that does not rotate is bursal tissue. Palpation of the coracoid and visualization of the redwhite junction allows identification and incision of the conjoint tendon at its lateral aspect. Once the interval is created and the strap muscles are exposed, a self-retaining Kolbel or Balfour retractor may be placed, with the medial aspect under the strap muscles and the lateral aspect under the deltoid. A single-pronged Hohmann retractor can be placed proximally between the rotator cuff and the coracoacromial arch. During placement of the Kolbel retractor, care must be taken to ensure that the axillary nerve is not entrapped. An alternative is to place a Hohmann or humeral head retractor under the deltoid laterally. Attention is then directed toward locating the long head of the biceps tendon and the subscapularis. Biceps tenodesis has been shown to improve functional outcome scores in a prospective cohort study of arthroplasty patients.22 The surgeon should then identify and cauterize the “three sisters,” or the anterior circumflex humeral artery with its two accompanying veins that run along the lower border of the subscapularis.



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Figure 6

Photograph demonstrating a cadaveric dissection in which the anterior deltoid origin has been elevated. The anatomy is visible after dissection through the deltopectoral interval at the level of the clavipectoral fascia. The long head of the biceps tendon (A), pectoralis major tendon (B), subscapularis tendon (C), lesser tuberosity (D), and strap muscles (E) can all be seen. The upper rolled border of the subscapularis and the site of a subscapularis tenotomy are indicated by the dashed line. (Reproduced with permission from Gadea F, Bouju Y, Berhouet J, Bacle G, Favard L: Deltopectoral approach for shoulder arthroplasty: Anatomic basis. Int Orthop 2015;39[2]:215-225.)

Subscapularis Management The subscapularis produces as much force as the remaining three rotator cuff muscles combined and plays a crucial role as the anterior portion of the force couple mechanism.23 Four options are available for management of the subscapularis tendon: tenotomy, lesser tuberosity osteotomy, “peel” of the tendon off the tuberosity, or a subscapularis split. The first three options differ primarily in the location of the disconnection between the musculotendinous unit and the humerus. Subscapularis tenotomy involves division of the tendon 1 cm from its insertion, with reattachment at the completion of the procedure achieved through sutures usually placed through the cut at the anterior humeral neck and through both leaflets of the tendon (Figure 6).

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Lesser tuberosity osteotomy involves a cut through the base of the medial aspect of the bicipital groove with elevation of the entire humeral subscapularis insertion. At the completion of the procedure, the lesser tuberosity osteotomy may be anatomically fixated with stout, reinforced suture material that is brought out through tunnels onto the lateral humeral cortex and tied over a plate.24 In a subscapularis peel, the tendon attachment is elevated from the lesser tuberosity as a sleeve of tissue. In a subscapularis split, the tendon is split in line with the muscle fibers. Each of these options has theoretical advantages. The tenotomy allows lengthening of the subscapularis but requires tendon-to-tendon healing. An osteotomy allows bone-to-bone healing as well as radiographic assessment of the repair, but the procedure may be technically challenging and may compromise the anterior humeral cortical rim. A peel allows a large surface area for healing but relies on the less favorable biology of tendon-to-bone healing. Because a subscapularis split provides strength superior to that achieved with a tenotomy, it is the preferred option if the surgery can be performed through this approach.11 A subscapularis split provides exposure to the glenoid equivalent to that of a tenotomy but provides minimal exposure of the humerus.12,16 Because all of these methods have demonstrated excellent results, controversy remains regarding which method provides optimal results.24-26 Recent studies have shown that both tenotomy and osteotomy have healing rates of nearly 100%.24,25 In a randomized clinical trial, Lapner et al26 found no difference in outcomes between a lesser tuberosity osteotomy and a subscapularis peel. However, several authors have demonstrated that even if the subscapularis heals anatomically, fatty infiltration occurs in many patients.10,24,26 If the repair fails, it portends poor outcomes and

potentially prosthetic instability for the patient.10,24,26 As a result, there has been a surge of interest in subscapularis-sparing approaches in which TSA and RTSA are performed either through the rotator interval using specialized instrumentation or with a partial subscapularis tenotomy through the inferior, muscular portion. Because some of these approaches have used a DS approach rather than a DP approach, these approaches are discussed in the DS section.15,16

Extension of the Approach Several options exist to extend the DP approach. Many surgeons routinely perform a partial tenotomy of the upper portion of the pectoralis tendon. In revision situations in which the anterior deltoid is frail and may not tolerate retraction, good results have been achieved with elevation of the origin of the deltoid.27 Exposure to manage a nonunion or malunion of a PHF is considered particularly challenging because of the altered anatomy. If possible, greater tuberosity osteotomy should be avoided because it has been linked to poor outcomes.28

Deltoid-splitting Approaches The subacromial space, rotator cuff, and glenohumeral joint can be approached by splitting the deltoid.2-4,29-31 Historically, these approaches have been combined with either acromial or clavicular osteotomy or elevation of the deltoid origin.1,31,32 Of these approaches, the most frequently employed technique is a split between the anterior and middle heads of the deltoid.14 Variations of this approach have been called the superolateral approach, the anterolateral approach, the minimally invasive approach, and the deltoidsplitting approach.2-4,29-31 These approaches are indicated for ORIF




of PHFs, TSA, RTSA, and open rotator cuff repair.2-4,29-31

Advantages and Disadvantages The DS approach offers several potential advantages. It avoids stress on the anterior deltoid. Theoretically, the decreased field of dissection could decrease the risk of osteonecrosis,17 but comparative trials have shown no differences.2,4 In addition, the DS approach avoids the significant retraction of the anterior deltoid that the DP approach can entail, which may impair recovery. In 1957, while describing his eponymous approach, Henry33 wrote “the [deltoid] muscle forms a thick unyielding cowl which gives when pulled aside a grudging revelation of bone and shoulder joint; and that will often be the last successful thing it does.” The DS approach also provides a more direct exposure of the tuberosities, and for RTSA, it provides a more in-line exposure of the glenoid.34 In a multicenter series of 527 RTSAs with a minimum 2-year followup, the DS approach provided a lower rate of postoperative prosthetic instability, possibly as a result of sparing the subscapularis or differences in implant positioning.15,34 Cosmesis is improved because the DS approach allows the use of a strap incision parallel to Langer lines that may be hidden by a bra strap.3 The DS approach also has several disadvantages. Dissection does not follow anatomic planes, and with scarring, the deltoid may become adherent to the humerus. In addition, the DS approach endangers the axillary nerve that runs under the deltoid. With this exposure, the deltoid origin is at risk of detachment, potentially creating an irreparable situation with severe functional consequences.6,7 The DS approach also provides less humeral exposure that may lead to retained inferior humeral neck osteophytes, a nonanatomic neck cut,

or an inappropriately sized prosthetic humeral head.16,35 Similarly, inferior exposure to the glenoid is limited, thereby increasing the risk for superior positioning or superior tilt of the glenosphere, which may lead to scapular notching. This exposure may also result in intraarticular penetration of screws during ORIF.2,4 The DS approach cannot be directly extended because of the location of the axillary nerve and the deltoid insertion but instead must be combined with a distal DP approach. Many surgeons may be uncomfortable performing revisions using this approach. As a result, a DP approach may be needed to revise a prior DS approach, potentially leading to anterior deltoid dysfunction. The blood supply to the deltoid proceeds from posterior to anterior under the posterior and middle heads and anterior to posterior under the anterior head, with the raphe between the anterior and middle heads representing a relatively bloodless “watershed” region.36 As a result, if the deltoid split is anterior or posterior to the raphe, the surgeon may disrupt the blood supply to a portion of the deltoid.36

Patient Positioning and Set-up In the DS approach, the patient may be positioned in the beach-chair position, the lateral decubitus position, or the supine position. Supine positioning allows the use of a radiolucent flattop Jackson table. For the lateral decubitus position, we use a suction bean bag to support the patient, combined with an axillary roll and adequate padding under the peroneal nerve and bony prominences.

Incision and Dissection Three options exist for the incision. The first option is an incision from the anterolateral corner of the acromion extending toward the deltoid

Figure 7

Preoperative photograph demonstrating one option for the deltoid-splitting approach for reverse total shoulder arthroplasty. The acromion, distal clavicle, coracoid, and coracoacromial ligaments have been marked on the skin and a 10cm incision has been marked obliquely crossing the anterolateral acromion. In this patient, the anterolateral deltoid was detached from the acromion; therefore, the incision is more medial and superior than for a purely deltoid-splitting approach. Anterior is toward the left side of the image. (Reproduced with permission from Molé D, Wein F, Dézaly C, Valenti P, Sirveaux F: Surgical technique: The anterosuperior approach for reverse shoulder arthroplasty. Clin Orthop Relat Res 2011;469[9]:2461-2468.)

insertion parallel to the fibers of the deltoid14 (Figure 7). The scar may be unsightly because this incision crosses Langer lines orthogonally.3,20 The second option is a strap incision parallel to the lateral border of the acromion, extending anteriorly and posteriorly, similar to the strap of a backpack3 (Figure 8). This approach follows Langer lines but requires creation of a flap, exposing the patient to a risk of flap necrosis.3 The third option is to perform a mini-strap small horizontal incision in line with Langer lines proximally just distal to the acromial edge to allow for fracture reduction and plate introduction, with accompanying percutaneous shaft screws placed into the shaft using a percutaneous technique.



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Figure 8

Intraoperative photograph demonstrating the completed deltoid split with the vessel loop passed around the axillary nerve (arrow). In this patient, a “backpack strap” incision has been used. A fracture within the greater tuberosity can be seen. (Reproduced with permission from Robinson CM, Khan L, Akhtar A, Whittaker R: The extended deltoid-splitting approach to the proximal humerus. J Orthop Trauma 2007;21[9]:657-662.)

After making the incision, the raphe is located between the anterior and middle heads of the deltoid. Distal traction on the arm causes the raphe to form into a sulcus. This interval can be bluntly opened proximally with scissors dissection or with a periosteal elevator. This allows entrance into the subacromial and subdeltoid spaces. After clearing the subacromial bursa, a finger is inserted proximally into the interval with the finger aimed distal and curved to palpate the axillary nerve, the only transverse structure running perpendicular on the undersurface of the longitudinal deltoid. It is critical to identify and protect this nerve. Typically, it is located 5 to 7 cm distal to the lateral acromial edge, but it is situated ,5 cm in 20% of patients.5 To ensure that the split does not extend beyond this level, placement of a stay suture may be necessary

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Extension and Variation of the DS Approach

Figure 9

Intraoperative photograph demonstrating the exposure of the glenoid through the deltoid-splitting approach. (Reproduced with permission from Molé D, Wein F, Dézaly C, Valenti P, Sirveaux F: Surgical technique: The anterosuperior approach for reverse shoulder arthroplasty. Clin Orthop Relat Res 2011;469[9]:2461-2468.)

(Figure 8). Once the split is made, the subacromial bursa often obscures the underlying structures. A complete bursectomy should be performed to visualize the greater and lesser tuberosities (Figure 9). For patients undergoing ORIF of PHF, control of the tuberosities may be obtained with placement of stout sutures through the rotator cuff tendons adjacent to their attachments, and a split between the tuberosities may be exploited for fracture reduction. If an RTSA is being performed, the joint may be entered through the rotator interval, and the remnant of the supraspinatus tendon can be excised to provide exposure. However, in patients with a functioning infraspinatus, care should be taken to preserve the fibers of the infraspinatus to allow for maintenance of postoperative external rotation strength. For patients undergoing ORIF of PHF, an additional split distal to the nerve may be made in line with the proximal split for placement of shaft screws. A protective cuff of muscle should be maintained around the nerve.

Historically, this approach was coupled with acromial osteotomy or elevation of the deltoid origin. Numerous series report healing rates of 100% of the deltoid origin with this technique.14,27,32 However, clinically devastating6 deltoid dehiscence can occur;7 thus, meticulous repair with nonabsorbable sutures placed in a grasping manner is crucial. One disadvantage of this technique is that it requires more prolonged immobilization for protection of the deltoid repair. The surgeon must be cautious with the use of this technique in patients with associated acetabularization because of a predisposition to acromial fracture and functional deltoid loss.15 Other described measures to improve the proximal exposure are acromioplasty14,16 or release of the coracoacromial ligament.15 An accessory distal DP approach may be used for distal extension.

Subscapularis-sparing Approach Recently, interest has surged in subscapularis-sparing approaches. RTSA, routinely performed in this manner in Europe with excellent results,34 is technically simpler because the supraspinatus can be excised. Lafosse et al16 reported good to excellent outcomes in 22 patients who underwent TSA performed entirely through the rotator interval, without glenohumeral dislocation, with a minimum 2-year follow-up. Modifications included elevation of 4.5 cm of the deltoid origin, acromioplasty, arthrotomy through the rotator interval, a custom humeral head-cutting guide, a reverse osteotome for removing inferior humeral neck osteophytes, stemless humeral head trials, and a specialized wrench for rotating the humeral component under the acromion after partial insertion. The




Figure 10

Intraoperative photograph demonstrating the incision for a posterior glenohumeral approach. Lateral is to the left of the image. The transverse limb extends along the scapular spine, and the longitudinal limb is at the joint line.

authors warned of three technical difficulties: difficulty in performing an anatomic humeral neck osteotomy, difficulty resecting inferior humeral neck osteophytes, and undersizing of the humeral head.16 Simovitch et al37 reported excellent outcomes in three patients with a minimum 1-year follow-up who underwent TSA through windows at both the rotator interval and the inferior subscapularis using specialized instrumentation. Savoie et al38 reported excellent outcomes in 43 patients with a minimum 2-year follow-up who underwent humeral hemiarthroplasty using a similar approach. The authors obtained MRIs for 19 patients at 2 to 5 years postoperatively, with no evidence of subscapularis fatty atrophy. Based on these early reports as well as the availability of short-stemmed prostheses, many surgeons and companies are currently investigating this approach and developing instrumentation to overcome the current technical challenges.

Posterior Approach The posterior approach to the glenohumeral joint, while unfamiliar to

Figure 11

Intraoperative photograph demonstrating the fascial incision at the lateral aspect of the deltoid (A), which is held with the forceps.

Figure 12

Intraoperative photograph demonstrating exposure of the posterior glenohumeral capsule (A) through a split between the infraspinatus (B) and the teres minor (C). The deltoid (D) is retracted with the retractor.

Figure 13

most orthopaedic surgeons, offers several unique advantages. A posterior approach is indicated for osseous augmentation of the posterior glenoid, posterior glenoid fractures, scapula fractures, and open decompression of the spinoglenoid notch.

Advantages and Disadvantages Advantages include excellent exposure of the posterior glenoid and access to the scapular neck and body. The main disadvantages of this approach include unfamiliar anatomy and potential damage to the suprascapular nerve if dissection extends medial to the glenoid. The actions of the posterior deltoid can be substituted by the long head of the triceps, the infraspinatus, and the teres minor; thus, damage to the posterior deltoid is less functionally significant than is damage to the anterior deltoid.

Patient Positioning and Set-up The patient is positioned in the lateral decubitus position. Prone positioning has also been described for this approach. The ability to manipulate the arm is crucial.

Intraoperative photograph demonstrating exposure of the humeral head (A) and the glenoid (B) with a longitudinal capsulotomy through the split between the infraspinatus (C) and the teres minor (D).

Incision and Dissection A curvilinear incision that begins along the scapular spine and turns distally toward the axilla at the posterior acromion provides the widest exposure (Figure 10). For posterior glenoid augmentation, only the longitudinal limb would be required. With 90" abduction, the posterior deltoid border overlies the glenohumeral joint. After dissection through the subcutaneous tissue, the posterior deltoid is retracted laterally and superiorly (Figure 11). Although historically this approach entailed detachment of the posterior deltoid and the infraspinatus, a recent cadaver study revealed that



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deltoid detachment provided no additional exposure of the lateral scapula, the spinoglenoid notch, or the glenoid.39 The internervous interval between the infraspinatus and the teres minor is identified (Figure 12). The fibers of the deltoid and infraspinatus are orthogonal; therefore, these intervals tend to fall closed. The interval between the infraspinatus and the teres minor lies within the inferior quarter of the glenoid and the inferior aspect of the glenoid; the humeral head can be used as a palpable landmark for identification of this interval. Generally, the interval can be easily bluntly dissected. The interval is generally easier to identify medially, where there may be a fat stripe between muscle bellies, than laterally, where the tendons can be confluent (Figure 13). Splitting the bipennate infraspinatus provides the surgeon direct access to the midpoint of the glenoid and offers a similar approach to a subscapularis split. Medially, elevation of the infraspinatus exposes the glenoid neck and the lateral border for ORIF. Once the split has been developed, a deep, self-retaining retractor may be placed, and a longitudinal capsulotomy can be made.

Extensions To and Variations on the Posterior Approach Distally, the axillary nerve and posterior humeral circumflex artery prevent extension of the approach. These structures lie roughly at the inferior convexity of the humeral head and at the inferior border of the teres minor.

Summary Surgical exposure of the shoulder is challenging because the deltoid and the rotator cuff musculature envelop the glenohumeral joint. Although the DP approach is most familiar to orthopaedic surgeons, it may not

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provide the optimal exposure in all cases. Some surgeons prefer the DS approach for ORIF of PHF for RTSA, where it may decrease instability. Although not commonly used, the posterior approach is crucial for posterior instability and scapular fractures. The ability to perform all of these exposures allows treatment of the greatest variety of pathology.

References Evidence-based Medicine: Levels of evidence are described in the table of contents. In this article, references 2 and 26 are level I studies. References 4, 17, 18, and 22 are level II studies. References 10, 15, and 19 are level III studies. References 6, 7, 9, 11, 13, 14, 16, 24, 25, 27-32, 35, 37, and 38 are level IV studies. References printed in bold type are those published within the past 5 years. 1. Boileau P, Watkinson DJ, Hatzidakis AM, Balg F: Grammont reverse prosthesis: Design, rationale, and biomechanics. J Shoulder Elbow Surg 2005;14(1, suppl S): 147S-161S. 2. Buecking B, Mohr J, Bockmann B, Zettl R, Ruchholtz S: Deltoid-split or deltopectoral approaches for the treatment of displaced proximal humeral fractures? Clin Orthop Relat Res 2014; 472(5):1576-1585. 3. Robinson CM, Murray IR: The extended deltoid-splitting approach to the proximal humerus: Variations and extensions. J Bone Joint Surg Br 2011;93(3):387-392. 4. Röderer G, Erhardt J, Kuster M, et al: Second generation locked plating of proximal humerus fractures: A prospective multicentre observational study. Int Orthop 2011;35(3):425-432. 5. Burkhead WZ Jr, Scheinberg RR, Box G: Surgical anatomy of the axillary nerve. J Shoulder Elbow Surg 1992;1(1):31-36. 6. Groh GI, Simoni M, Rolla P, Rockwood CA: Loss of the deltoid after shoulder operations: An operative disaster. J Shoulder Elbow Surg 1994;3(4): 243-253. 7. Sher JS, Iannotti JP, Warner JJ, Groff Y, Williams GR: Surgical treatment of postoperative deltoid origin disruption. Clin Orthop Relat Res 1997;343:93-98.

8. Flatow EL, Bigliani LU: Tips of the trade. Locating and protecting the axillary nerve in shoulder surgery: The tug test. Orthop Rev 1992;21(4):503-505. 9. Harris JD, Gupta AK, Mall NA, et al: Longterm outcomes after Bankart shoulder stabilization. Arthroscopy 2013;29(5): 920-933. 10. Scheibel M, Nikulka C, Dick A, Schroeder RJ, Popp AG, Haas NP: Structural integrity and clinical function of the subscapularis musculotendinous unit after arthroscopic and open shoulder stabilization. Am J Sports Med 2007;35(7): 1153-1161. 11.

Paladini P, Merolla G, De Santis E, Campi F, Porcellini G: Long-term subscapularis strength assessment after Bristow-Latarjet procedure: Isometric study. J Shoulder Elbow Surg 2012;21(1):42-47.

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