Modified Radical Mastectomy

Transcription

1 Modified Radical Mastectomy Valerie L. Staradub, MD, and Monica Morrow, MD S urgical management options for breast cancer include modified radical mastectomy (MRM), MRM with immediate reconstruction, and breast conservation therapy (BCT). Absolute contraindications to BCT include tumor presence in more than one breast quadrant, diffuse suspicious or indeterminate calcifications seen on mammography and contraindications to radiation therapy, such as first or second trimester of pregnancy or history of radiation therapy to the breast field for previous breast cancer or as part of treatment for another condition, such as Hodgkin's disease. 1 Relative contraindications include sufficiently large tumor-to-breast ratio to preclude acceptable cosmesis and collagen vascular disease. The incidence of these contraindications varies with tumor stage. In our experience, 10% of women with stage I breast cancer and 28% of women with stage II breast cancer had contraindications to BeT. 2 In women with contraindications to BCT, MRM is medically necessary. For all others, there is no survival difference between the procedures, and patient preference should be the deciding factor. We have observed that approximately 20% of women who are candidates for BCT opt to undergo MRM. Nationally, MRM remains the most common treatment for patients with stage I and II breast cancer. 3-5 In some situations, MRM is not an appropriate first-line treatment modality, and the patient should be referred for neoadjuvant chemotherapy; these include metastatic breast cancer and locoregionally advanced carcinoma. 6-7 In addition, patients presenting with stage IV carcinoma are surgical candidates only if they develop local complications that cannot be controlled with systemic therapy. MRM always includes removal of the breast tissue, the nipple-areolar complex, and the ipsilateral axillary lymph nodes. Variations of the procedure, including removal of the pectoralis minor muscle or division of its tendon to facilitate axillary exposure, have been described, sq~ In our experience, these are rarely, if ever, necessary, and the technique that we describe keeps the pectoralis minor intact. The original descriptions of MRM included removal of the pectoralis major fascia, because this structure was thought to be a barrier to the lymphatic spread of tumor. Subsequent studies have shown that lymphatic vessels penetrate the pectoral fascia and that this fascia may be preserved when needed to facilitate implant reconstruction, as long as care is taken to meticulously remove all of the breast tissue superficial to the fascia. MRM is an extremely safe operation with a very- low operative mortality rate. This is true even in the elderly population, for which the mortality rate from breast surgery of all types is less than 2% Patient Positioning and Preparation 1"he patient is positioned supine on the operating table with the ipsilateral arm abducted 90 ~ on an arm board. The arm board is padded to prevent subluxation of the shoulder with brachial plexus stretch. The patient is positioned at the edge of the table on the operative side; it may be helpful to place a folded sheet under the ipsilateral shoulder. The axilla is shaved if necessary, and a standard surgical preparation is done. The breast preparation should extend below the mframammary crease, across the midline, and to the supraclavicular fossa in the event that extra skin mobilization is needed to allow closure. The entire ipsilateral arm is prepped to the wrist, the arm board is covered with a Mayo stand cover, and the arm is draped with an impervious stockinet. The field drapes are brought underneath the ipsilateral shoulder so that the entire arm is in the operative field. From the Lynn Sage Comprehensive Breast Center, Department of Surgery, Northwestern University Medical School, Chicago, IL. Address reprint requests to Monica Morrow, MD, Director, Lynn Sage Comprehensive Breast Center, Northwestern Memorial Hospital, 251 E. Huron St., Gaiter , Chicago, IL Copyright by WB. Saunders Company X/00/ /0 doi: /otgn Operative Techniques in General Surgery, Vol 2, No 2 (June), 2000: pp

2 Modified Radical Mastectomy 119 SURGICAL TECHNIQUE 9.:~! = [ A Mastectomy incision after upper biopsy B Mastectomy incision after lower inner biopsy ia x 1 The surgeon stands below the arm board, and the first assistant is positioned cranial to the arm board on the ipsilateral side. A second assistant may be positioned on the contralateral side. An antibiotic with a broad spectrum of gram-positive coverage (eg, a first-generation cephalosporin) is given before the incision is made if the patient has had a prior open biopsy or preoperative chemotherapy or is otherwise immunosuppressed. The incision line is drawn with a marker and includes the nipple-areolar complex, the biopsy site if carcinoma was diagnosed with a surgical biopsy, and any excess breast skin. The incision can be oriented in any way that facilitates inclusion of these structures (A and B). Care is taken to not extend the incision medially to the sternum or laterally off the breast mound, as this will result in unsightly dog-ears. Exposure in these areas is obtained by raising flaps. Tumescence solution, consisting of 1 L of lactated Ringers' solution with 30 ml of 1% lidocaine solution with epinephrine at 1:1000, is used to allow a hemostatic dissection with the knife. This technique was developed for liposuction and is used to reduce blood loss in various plastic surgical flap procedures. When used for mastectomy, it is critical that the skin incision be planned before the infusion of tumescence fluid, because it is difficult to accurately determine the amount of skin that must be removed once the breast has been filled with fluid. Tumescence may be delivered with a pressure infusion system or manually. In pressure infusion, several stab incisions are made with a #15 blade inside the fine of planned resection for insertion of a blunt needle. The tumescence solution is infused into the subcutaneous space over the entire area of the planned dissection and into the deep substance of the breast. The solution is infused until the breast is firm to the touch, which, depending on breast size, may require between 500 ml and 1 L of solution. Care should be taken to avoid injecting the solution directly into the tumor bed itself. When manual injection is used, a spinal needle is attached to a spring-loaded syringe with a 3-way stopcock and intravenous extension tubing. These needles can reach the axillary vein, so care must be taken when injecting in this area.

3 120 Staradub and Morrow Clavicle Sternum iil/il '{ ' Latissimus dorsi?ii;!{!i!i :ili!i : e:= r.:: : { 2, The incision is made with the knife along the previously sketched lines. With skin hooks used to elevate the skin, skin flaps are raised with a #10 blade in the plane deep to the subcutaneous fat and superficial to the breast parenchyma. The thickness of the flap will vary with the amount of subcutaneous fat present. Manual retraction of the breast tissue away from the skin tends to show this plane quite effectively. Surgeons accustomed to determining flap thickness by palpation need to be aware that the use of tumescence solution causes the flaps to feel thicker. Flaps are raised superiorly to the level of the clavicle, medially to the edge of the sternum, inferiorly to the superior aspect of the rectus sheath, and laterally to the latissimus dorsi muscle. Once all flaps have been raised, the pectoralis major fascia is elevated off the muscle with the knife, beginning at the superior aspect of the breast and continuing inferiorly. Perforating vessels along the sternal edge are ligated and divided as they are encountered, and smaller perforators from the muscle are cauterized. The breast is left attached at the inferolateral edge to provide retraction during the axillary dissection. The breast is then freed from the lateral edge of the pectoralis maj or muscle; the medial pectoral bundle should be preserved. The muscle is gently retracted with a small Richardson retractor, and the axillary investing fascia is opened along the edge of the pectoralis minor to allow placement of a retractor beneath it during the axillary dissection.

4 Modified Radical Mastectomy 121 Axill ary vein :~i' I i 3 Attention now turns to the axilla. The previously identified edge of the latissimus dorsi muscle is followed cranially until it turns tendinous, where it is crossed by the axillary vein. The intercostobrachial nerves are encountered approximately halfway up the latissimus and are identified during this step and preserved to avoid numbness of the upper inner arm. No other important structures cross this plane of dissection, making it the safest approach to the axillary vein. Once the axillary vein is identified, its overlying fat is divided in a lateral-to-medial fashion. Care is taken to avoid stripping the vein completely of overlying fat and lymphatics, which may increase the potential for lymphedema. Dissection superior to the vein also must be avoided. When the vein has been exposed, dissection once again commences in a lateral-to-medial fashion just below the vein. Dissecting approximately 5 mm below the vein rather than immediately on the inferior surface will avoid creating a side hole in the vein in the event that a branch is inadvertently transected. There is often a large lymphatic vessel traversing parallel to the vein on its inferior surface; this should be preserved, if possible. With the first assistant providing caudal traction on the axillary contents, the surgeon dissects the superficial fat and divides the branches of the axillary vein and ties them with 3-0 silk as they are encountered. An anterior thoracic branch usually overlies the deeper thoracodorsal vein. However, the surgeon should carry out the dissection systematically, layer by layer, rather than attempting to initially identify the deeper vein branches or the thoracodorsal or long thoracic nerves early in the dissection.

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