Atlas of General Surgical Techniques (Courtney M. Townsend Jr., B. Mark Evers)

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STEP 3: OPERATIVE STEPS

1. INCISION

The patient is placed supine, close to the edge of the operating table with the arm extended on a padded arm board, with or without a wedge. The arm may be prepped separately and covered in a sterile stockinette to allow free rotation of the arm medially, to relax the pectoralis major and minor muscles, and to permit better exposure of the axilla.

The type of incision depends on whether immediate reconstruction is planned or a delayed procedure is anticipated. If no reconstruction or a delayed procedure is planned, an elliptical incision is made to include a previous surgical biopsy site if present (Figure 10-3). The incision is usually placed horizontally to include the nipple-areolar complex, but in some cases may be oriented at different angles to include a previous surgical biopsy site. If delayed reconstruction is anticipated, the medial extent of the incision may be angled slightly caudad to permit sufficient skin for reconstruction of the medial cleavage and to avoid a scar that may be visible with low décolletage. The width of skin resection should permit a tension-free closure but avoid redundant skin folds. A good way to judge the amount of skin to be resected is to draw a transverse or angled line through the nipple and move the inferior flap upward with gentle tension and draw a mark on the skin where it intersects the transverse line. A similar action should be performed for the superior flap.

If immediate reconstruction is planned, discussion with the plastic surgeon for placement of incisions is important. The most natural appearance to the native breast is a skin-sparing mastectomy that is accomplished by resecting the nipple-areolar complex and leaving most of the skin envelope behind. If the nipple areolar-complex is small relative to the breast, a transverse incision can be extended laterally, resembling a tennis racquet, for a short distance sufficient to reach the axillary nodes.

A marking pen is used to draw the planned incision. The skin is incised with a no. 15 scalpel and extended through the dermis into the subcutaneous adipose tissue to expose the superficial investing fascia of the breast (Figure 10-4). The thickness of the flaps will vary according to body mass index. In very lean individuals this can be just millimeters thick and may require subcutaneous infusion of tumescence solution for easier dissection. The breast parenchyma lies closest to the skin at the nipple-areolar complex and increases in thickness toward the periphery of the breast.

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2. DISSECTION

Dissection is initiated by elevating the skin edges with skin hooks or Freeman rake retractors and may be performed with electrocautery as illustrated or by sharp dissection with a no. 10 scalpel or curved Gorney scissors (Figure 10-5). If sharp dissection is undertaken, subcutaneous injection of a dilute saline solution with epinephrine may reduce bleeding.

As the flaps are elevated, the assistant holds upward tension on the skin flaps while the surgeon uses countertraction on the breast parenchyma. These counter forces help expose the fine avascular areolar fascial plane separating the subcutaneous fat from breast parenchyma. Excessive bleeding indicates that the dissection is not in the correct anatomic plane that separates the glandular tissue from the subcutaneous adipose tissue.

Dissection is continued circumferentially following the superficial fascia to its fusion with the muscular fascia around the anatomic borders of the breast. These are defined by the pectoralis major muscle below the clavicle superiorly, the margin of the sternum medially, the inframammary fold overlying the rectus abdominis muscle inferiorly, and the serratus anterior muscle to the latissimus dorsi muscle laterally. Dissection along the latissimus dorsi muscle continues to the level of its tendinous insertion just inferior to the axillary vein.

The resection of the breast off the chest wall posteriorly includes the retromammary fascia with the investing fascia of the pectoralis major muscle.

The mammary gland with the superficial fascia and the posterior investing fascia of the pectoralis major muscle is resected from superomedial to inferolateral, exposing the axillary fat pad containing the draining lymph nodes and the lateral aspect of the pectoralis major muscle (Figure 10-6). Care should be taken to dissect the fascia in the avascular plane parallel to the muscle fibers to avoid transection of muscle fibers, especially along the sternal insertion medially and along the rectus sheath inferiorly. The fascia of the serratus anterior muscle should be left intact if immediate implant reconstruction is planned, unless contraindicated by disease.

Perforating muscular blood vessels and intercostal vessels should be ligated with 3-0 silk ligatures or be cauterized. Care should be taken to avoid traction on these vessels, which have a tendency to retract and be an occasional source of postoperative bleeding. Blind dissection for these vessels may lead to entry into the chest cavity and pneumothorax.

The breast remains attached laterally exposing the axilla, the pectoralis major muscle medially, and the latissimus dorsi muscle laterally.

The boundaries of the axilla are defined by the pectoral muscles medially, the latissimus dorsi muscle laterally, the axillary vein superiorly, and the subscapularis and teres major muscles posteriorly.

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Dissection of the axilla is undertaken by incising the fascia of the pectoralis major muscle from inferior to superior (Figure 10-7). Care must be exercised to avoid injury to the medial anterior thoracic nerve (medial pectoral nerve), which may penetrate both pectoral muscles and emerge medially or may course along the lateral aspect of the pectoralis minor muscle. Injury to this nerve may lead to atrophy of part of the pectoralis major muscle.

The fascia along the pectoralis major muscle is incised and retracted medially with a small or medium Richardson retractor, exposing the underlying pectoralis minor muscle (Figure 10-8). The clavipectoral fascia along the pectoralis minor muscle is then incised, and the retractor is replaced exposing the level II nodes posterior to the pectoralis minor muscle. The arm may now be rotated medially to take tension off the pectoral muscles and expose the axillary contents. Care must be taken to avoid traction of the extremity and the brachial plexus in the anesthetized patient.

The intercostal brachial cutaneous nerve may be identified coursing transversely below the axillary vein and should be preserved if free of matted tumor-laden nodes to avoid bothersome sensory dysesthesias along the medial aspect of the upper arm.

Dissection medially should be cautious, with attention to the long thoracic nerve, which lies on the serratus anterior muscle beneath the fascia. Retraction of the fascia off the chest wall will pull the long thoracic nerve off the chest wall and place it at risk of injury. The nerve can be identified deep to the intercostal brachial nerve or higher, inferior to the axillary vein on the chest wall, where it is less likely to have been pulled away from the serratus anterior muscle into the axillary fat. The nerve should be protected and preserved. The function can be confirmed by very gentle compression and demonstration of contraction of the serratus muscle in the unparalyzed individual. Injury to the long thoracic nerve causes a winged scapula.

Lateral dissection of the axilla is along the latissimus dorsi muscle to the tendinous insertion. The axillary vein overlies the tendinous insertion, and care should be taken to proceed cautiously from lateral to medial and from superficial to deep, with careful visualization of underlying structures.

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3. CLOSING

Two closed suction drains, such as #10 Jackson-Pratt drains, are inserted through separate small stab incisions inferior and lateral to the skin incision, one oriented toward the axilla and the second anteriorly beneath the skin flaps. The drains are secured in place with 2-0 silk sutures.

The skin is closed in two layers with absorbable sutures, a deep layer of 3-0 Vicryl sutures, and a subcuticular closure with 4-0 Monocryl sutures (Figure 10-12). Steri-Strips or Dermabond may be used for skin approximation. A light dressing or special mastectomy bra is applied with loose fluff gauze dressings.

Incision closed with subcuticular running suture

Drainage catheters

FIGURE 10–12