Modified Radical Mastectomy

Over the past 20 years, multiple international clinical studies have shown equivalent survival between patients treated with modified radical mastectomy and appropriately selected patients treated with breast-conserving surgery and adjuvant radiation, hormonal therapy, and chemotherapy. Accordingly, breast-conserving surgery has become the dominant mode of treatment, with modified radical mastectomy becoming the alternate choice in certain circumstances. A residual large cancer after adjuvant therapy (especially in a small breast), multicentric cancers, and patient preference or concerns about the complications of radiation therapy are the principal indications for the operation. Prior to surgery, the opposite breast should be evaluated by physical examination and mammography. Appropriate blood tests and imaging scans and mammographic studies are made in a search for potential metastases to the lung, liver, or bone. The standard preadmission physical examination and laboratory evaluations are done in an ambulatory setting, as most patients are admitted to the hospital on the day of operation.

The skin over the involved area should be inspected for signs of infection. The skin is shaved and electrical hair clippers may be used over the axillae. Some surgeons give a single perioperative dose of parenteral antibiotics, particularly if a regional breast biopsy has recently been performed.

General anesthesia is given via an endotracheal tube. Short-acting muscle depolarizing agents should be requested for the intubation, such that the motor nerves will be responsive during the axillary node dissection.

The patient is placed nearest the margin of the operating table on the side of the surgeon. The arm is abducted and held by an assistant or placed upon a support at right angles to the patient to facilitate the preparation of the skin. Some prefer to wrap the arm, including the hand, in sterile drapes so that the arm can be moved upward as well as medially to facilitate the subsequent dissection of the axilla.

The skin is widely prepared with topical antiseptics. This includes not only the involved breast but also the area over the sternum; the supraclavicular region, shoulder, axilla, and collateral chest wall; as well as the upper abdomen on the involved side. A slight Fowler position with a tilt away from the surgeon improves the exposure. The surgical drape should be secured to the skin at appropriate points around the margin of the proposed field of operation. The arm should be free to be moved by an assistant as required for exposure in the axilla.

If the diagnosis of malignancy has not been documented by previous biopsy, the diagnosis is first confirmed by a biopsy of excised tumor using frozen-section examination by the pathologist. The specimen is also sent for hormone binding and other immunoassays. The underlying pectoralis muscle should not be involved in any way by the biopsy; otherwise that section of the muscle should be excised en bloc with the specimen. After the biopsy wound is closed and sealed, all instruments and gloves used in the procedure are discarded. Some prefer to have a second sterile table available, which results in a repeated complete skin preparation and sterile draping. Every precaution should be taken to avoid seeding with malignant tumor.

With proof of malignancy, an oblique elliptical incision is made that may include a short extension laterally up toward the axilla to ensure a better exposure for the axillary dissection and a more cosmetically acceptable closure (Figure 1). The transverse segment of the elliptical incision includes the nipple and areola and an appropriate distance of 5 to 7.5 cm beyond the limits of the tumor whenever possible. If reconstructive surgery is planned, a more limited incision (Figure 1, dashed line) that preserves skin can be made in consultation with the plastic surgeon. The entire nipple plus an adequate margin about the biopsy site must be taken, while a lateral, comma-like extension provides the exposure for the axillary dissection.

The initial incisions through the skin should be only 1 cm or so deep, since it is advisable to include most of the subcutaneous tissue, especially in the region of the axilla, with the final specimen (Figure 2). The skin flaps require careful elevation, with control of all bleeding points as the dissection progresses. The flaps are elevated to the level of the clavicle superiorly, to the edge of the sternum medially, to the rectus sheath and costal margin inferiorly, and then laterally to the edge of the latissimus dorsi muscle. Particular attention is required to remove as much subcutaneous fat as possible in the axillary region, because the lymph nodes and breast tissue are very close to the skin in this region.

The fascia over the pectoralis major muscle as well as the breast is resected as a subfascial dissection starting near the clavicle and extending downward over the midportion of the sternum (Figure 3). The fascia is meticulously dissected off the pectoralis muscle without including any of the latter within the gross specimen. If the cancer has penetrated this fascia and invaded the pectoralis major muscle, that section of the muscle can be excised en bloc with the specimen. It is usually not necessary to perform a full radical mastectomy with removal of the entire pectoralis major muscle. The perforating intercostal arteries and veins near the sternal margins must be carefully clamped and ligated.

The axillary flap is retracted upward, and the fascia over the edge of the pectoralis major is incised (Figure 4), exposing the pectoralis minor muscle beneath and the junction of the coracobrachialis and pectoralis minor origins superiorly at the coracoid process. Electrodiathermy is often used in this operation, but it should be avoided about the axillary vessels and nerves and for control of bleeding from intercostal perforating vessels lateral to the sternum. The loose tissue over the axillary vein is incised and the vein wall gently exposed for a short distance beyond the subscapular vessels (Figure 5).

Level I and II lymph nodes are removed in the axillary node dissection that begins by incising the clavipectoral fascia along the lateral edge of the pectoralis minor muscle. Precautions are taken to avoid the medial and lateral nerves to the pectoralis major muscle. The medial nerve is so named because it arises from the medial cord of the brachial plexus and then passes through the pectoralis minor muscles in about 60 percent of patients or passes laterally around the pectoralis minor in 40 percent en route to innervating the lower region of the pectoralis major muscle (Figure 6). The dominant lateral nerve to the pectoralis major muscle arises from the lateral cord. It passes medial to the pectoralis minor muscle near its insertion and is closely associated with the acromial thoracic artery.

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The lateral edge of the pectoralis minor is cleared of fascia to near its insertion on the corticoid process and several veins are ligated as they come off the axillary vein (Figure 7). A careful search is made for the medial nerve to the pectoralis major, which is preserved. Ligation rather than electrocoagulation is preferred for all vessels about the axilla and for those adjacent to the sternum.

The pectoralis major and minor are retracted upward and medially, exposing the uppermost tissues to be divided over the axillary vein. Some prefer to divide the pectoralis minor muscle from its insertion on the coracoid process as to gain better exposure of the medial area of the axillary vein and its lymph nodes.

The fascia over the serratus anterior muscle is dissected free, and the axillary fat and lymph nodes are mobilized off the chest wall and the axillary vein (Figure 8). The arm, wrapped in sterile drapes, is lifted up or manipulated to enhance the exposure as the dissection progresses in the axilla. The long thoracic nerve should be identified deep to the axillary vein. As it lies within the loose fascia over the serratus anterior muscle, it is possible to lift this nerve away from the muscle; hence, it must be carefully sought and dissected out from the axillary contents to be contained within the resected specimen. This nerve should be retained intact, because a “winged” scapula will result if it is divided. A sensory nerve that is often sacrificed is the more transverse intercostobrachial that appears beneath the second rib and provides sensory innervation to the upper inner aspect of the arm.

As the breast is retracted laterally (Figure 9), the long thoracic nerve as well as the thoracodorsal nerve should be free of redundant tissue. The thoracodorsal nerve is characteristically located adjacent to the deep subscapular vein and artery. Division of the thoracodorsal nerve is avoided unless there is tumor involvement, since its sacrifice has only a partial effect upon the latissimus dorsi muscle.

The specimen is freed from the latissimus dorsi muscle (Figure 10) and finally from the suspensory ligaments in the axilla, where large veins and lymphatics should be carefully ligated. The operative area is repeatedly inspected for any bleeding points, which are ligated. The two major nerves are checked to be certain that their course is free of ligature, and their integrity is verified by a brisk but gentle pinch that results in an appropriate muscle twitch. The wound is irrigated with saline, and a final inspection is made for hemostasis prior to closure. Two closed-system perforated suction catheters are inserted for drainage. They are usually introduced through separate stab wounds made in the lower flap posteriorly. One catheter is directed up to the axilla. The other catheter is secured anterior to the pectoralis major muscle for drainage from under the skin flaps. The catheters are secured to the skin with nonabsorbable sutures and attached to a closed system of suction (Figure 11).

It is very important that the surgeon spend the necessary time and effort to compress the skin flaps into place in the axilla and elsewhere as the skin is finally closed. If the skin flaps are so thin that there is minimal subcutaneous tissue, interrupted sutures are used in the skin. Alternatively, some surgeons use a few interrupted absorbable sutures in the subcutaneous fat in medium-thickness skin flaps.

The manner of dressing the incision is controversial. In the Auchincloss method, the skin is cleaned, dried, prepared with tincture of benzoin, and approximated with very large strips of elastic tape. These start above the level of the clavicle and extend down to the level of the drains. Others apply a simple gauze dressing and a surgical bra, whereas some prefer bulky fluffed dressings followed by gauze or elastic bandage wrappings.

Skin sutures, if present, are removed in 3 to 5 days, with the incision being reinforced with “butterfly” adhesive strips. The suction catheters are removed in approximately 2 to 5 days, when the drainage is less than 30 mL per day. Any collections of fluid may be aspirated in the surgeon's office using strict adherence to aseptic precautions. Normal use of the arm is encouraged for the first week; thereafter, active shoulder exercises are performed to ensure return of full range of motion within the ensuing 2 weeks. Physical therapy may be necessary if progress is not apparent in this interval. The patient is cautioned to minimize cuts and possible infection in this arm and to report immediately any injury that results in infection, since a rapidly spreading lymphangitis is possible. Finally, a systematic regimen for lifelong follow-up is instituted even if the final pathologist's report does not indicate the need for additional therapy at the time.