The patient can be set up in either the beach chair or lateral decubitus position. Our preference is the lateral decubitus position based on ease of setup, improved mechanical access to areas of the shoulder, decreased risk of cerebral hypoperfusion, which facilitates safer maintenance of lower mean arterial pressures and improved visualization.¹¹

After induction under general anesthesia, the patient is rolled over a vacuum beanbag with an axillary roll placed under the down axilla. Pillows are placed between the legs. The beanbag is secured with the operative side rolled back about 20° to 30° toward the surgeon. The operative site is wiped with hydrogen peroxide prior to final prepping and draping. The arm is then positioned in an articulated arm positioner with axial traction in 20° of flexion and 20° to 30° of abduction.

The surgeon stands against the patient’s back. If working on a right shoulder, the surgeon’s right side is against the body. The first assistant stands at the head of the patient. A mayo stand is placed across the surgeon and holds the shaver, the electrocautery wand, and the arthroscopic tubing. A second mayo stand is placed on the same side of the surgeon and holds the instruments used throughout the case. The surgical technician stands on the operative side next to the surgeon (Figure 12-1).

The pump pressure starts low at 40 mm Hg and is raised only if needed. A dedicated outflow cannula is also avoided to decrease turbulence. The rationale for this avoidance stems from the Bernoulli effect, whereby fluid moves from a high-pressure system to a low-pressure system. The higher the gradient, the more turbulence and hence, bleeding occurs. Additionally, minimizing fluid egress also controls turbulence and use of cannulas and assistants plugging leaky portals is also helpful.

Proper portal placement is essential to achieve optimal angles of visualization and angles of approach. As such, after the initial posterior portal is made, all other portals are established in an “outside-in” fashion with an 18-gauge spinal needle. Placement of accessory portals is also encouraged if standard portals or arm positioning does not afford proper angles of approach.¹²

The posterior viewing portal is first established approximately 3 cm distal and 2 cm medial to the posterolateral corner of the acromion. This places access to the glenohumeral joint at or slightly above the humeral head equator.

Anteriorly, a standard anterior portal can be established just superior to the lateral half of the subscapularis tendon. Often times, however, an anterosuperolateral (ASL) portal is established instead to address subscapularis or biceps pathology. The ASL portal is made 1 to 2 cm anterolateral to the anterolateral acromion at a 5° to 10° angle of approach to the lesser tuberosity, anterior to the supraspinatus taking care not to violate the rotator cable posteriorly.

After entering the subacromial space through the same initial posterior viewing portal, a lateral portal is established. The portal is approximately 4 cm lateral to the acromion and parallel to the undersurface of the acromion. As rigid cannulas can restrict the movement of instruments, initial subacromial work is often performed without a cannula. A cannula is then placed for suture passage and anchor placement (Figure 12-2).

Percutaneous accessory portals are also created as necessary just lateral to the acromion for medial row anchor placement.

The debate between double-versus single-row repairs is beyond the scope of this chapter.¹³ When comparing unlinked double row to suture-bridging double-row repair, the latter has demonstrated superior biomechanical and clinical performance.^14,15 As such, if there is adequate tendon mobility and quality, a suture-bridging double-row repair is the preferred construct to anatomically restore the footprint. However, in cases of tendon loss or inadequate mobility, over tensioning of the repair is avoided and a single row-repair is performed instead, typically with rip-stop configurations.

Advanced mobilization techniques are performed as necessary to aid in tendon reduction and to decrease tension on repairs.

Subscapularis tendon tears are commonly found with posterosuperior tears. If present, subscapularis release and repair are necessary to restore force couples and reduce tension on the superior cuff.¹⁶
It is important to note that the comma tissue represents a connection between the anterior supraspinatus and superior subscapularis. Thus, reduction of a retracted subscapularis tear will facilitate repair of the supraspinatus tendon. This is also why we always prefer to leave this tissue intact.

Tendon mobility is assessed after a complete bursectomy in the subacromial space. If further mobility is required, an anterior interval slide in continuity and capsular releases are performed. We rarely perform a posterior interval slide as this release violates the rotator cable.

The anterior interval slide in continuity releases the coracohumeral ligament (CHL) while preserving the comma tissue between the supraspinatus and subscapularis. This release can provide an additional 1 to 2 cm of tendon mobility. In contrast to a classic anterior interval slide, which separates the anterior edge of the supraspinatus from the rotator interval, the anterior interval slide in continuity maintains the connection laterally between the supraspinatus and subscapularis. Of note, the anterior interval slide in continuity is the same as the superior subscapularis release and would have been performed while addressing the subscapularis.

A 70° arthroscope is introduced from the posterior viewing portal while working through the ASL portal. A traction suture can be placed in the anterior aspect of the supraspinatus tendon and retrieved through an accessory percutaneous portal. The rotator interval is opened with electrocautery just above the upper border of the subscapularis. Dissection is carried out medially to the glenoid neck anterior to the labrum. The base of the coracoid is identified as the bony prominence just anteromedial to the biceps root. Once palpated, it is cleared (Figures 12-3 and 12-4).

If further mobilization is needed after an anterior interval slide, a capsular release is performed via a lateral working portal. This affords an additional 1 to 1.5 cm of supraspinatus excursion. The release begins at the end point of the anterior interval slide in continuity. Dissection is carried out along the glenoid, medial to the labrum. The release is carried as posteriorly and inferiorly as can be visualized with a 70° arthroscope (typically to the 7 o’clock position in a right shoulder). Medial dissection greater than 1 cm is avoided to protect the suprascapular nerve.