Townsend Courtney M.Jr., Evers B. Mark. Atlas of General Surgical Techniques: Expert Consult

Подождите немного. Документ загружается.

117

STEP 1: SURGICAL ANATOMY

◆ A comprehensive understanding of the location of the mammary gland in relation to the

chest wall musculature, the fascial boundaries, the lymphatic drainage pathways, the vascu-

lar supply to the breast and the associated supporting structures, and the innervation of the

breast and surrounding tissues is essential for appropriate surgical management.

◆ Figure 10-1 demonstrates the breast gland and the rich intraparenchymal lymph channels

coursing toward the deeper major nodal reservoirs.

◆ Figure 10-2 illustrates the relationship of the nodal basins to the chest wall musculature.

The lymph nodes lateral to the pectoralis minor constitute level I nodes, those immediately

beneath the pectoralis minor level II nodes, and those medial to it level III. The interpectoral

nodes (Rotter’s nodes) are located between the pectoralis major and minor muscles and are

part of level III nodes. Internal mammary nodes are located medially along internal mam-

mary vessels beneath the sternum. Unnamed intramammary lymph nodes can be present in

all quadrants of the breast.

DEFINITION

◆ Modiﬁ ed radical mastectomy constitutes the removal of the breast parenchyma, the nipple-

areolar complex, and levels I and II axillary lymph nodes.

◆ Other types of mastectomy procedures include the following:

◆ Total mastectomy (removal of the breast only) may be combined with sentinel node

biopsy.

◆ Patey’s modiﬁ ed radical mastectomy includes dissection of level III nodes reached by

division or resection of the pectoralis minor muscle.

◆ Radical mastectomy further removes the pectoralis major and minor muscles.

◆ Extended radical mastectomy also eradicates the internal mammary lymph nodes.

◆ Nipple-sparing mastectomy preserves the nipple and areola.

◆ Areola-sparing mastectomy preserves the areola, usually with resection of the nipple.

CHAPTER

Modiﬁ ed Radical Mastectomy

Baiba J. Grube

118 Section II • The Breast

STEP 2: PREOPERATIVE CONSIDERATIONS

◆ Selection of a surgical option for local control of breast cancer is a complex decision that is

based on tumor features, body habitus, and individual patient choice. Interdisciplinary

discussion with radiation oncologists, medical oncologists, and plastic surgeons in addition

to the oncologic surgeon provides a comprehensive understanding of the options available

to the patient.

◆ Modiﬁ ed radical mastectomy may be an option for a diagnosis of the following:

◆ Invasive breast cancer

◆ Multicentric invasive breast cancer

◆ Invasive breast cancer after previous chest irradiation

◆ Invasive breast cancer when postoperative radiotherapy maybe contraindicated (e.g., con-

nective tissue disease, presence of a pacemaker)

◆ Invasive breast cancer in a pregnant patient

◆ Palliative resection in stage IV breast cancer for local control

◆ Lumpectomy with axillary lymph node dissection may be an alternative procedure to modi-

ﬁ ed radical mastectomy for many women, especially in the current era of mammographic

screening and identiﬁ cation of early stage disease, or with the use of induction chemotherapy

to reduce the size of a larger primary tumor.

◆ Discussion of the planned procedure with the anesthesiologist is critical.

◆ Long-acting paralytic agents should be avoided when an axillary dissection is planned so

that intact motor nerve function can be detected.

◆ Inhalation agents may be varied if immediate reconstruction is planned with autologous

tissue.

CHAPTER 10 • Modiﬁ ed Radical Mastectomy 119

Interpectoral nodes

Pectoralis minor muscle

Central axillary

nodes

Subscapular axillary

pectoral nodes

Anterior axillary

pectoral nodes

Brachial axillary

nodes

FIGURE 10 –1

Serratus anterior muscle

Long thoracic nerve

Subscapular muscle

Latissimus dorsi muscle

Thoracodorsal

artery, nerve, and vein

Axillary vein

Axillary artery

Cephalic vein

Medial anterior

thoracic nerve

Medial anterior

thoracic nerve

Lateral anterior thoracic nerve

Perforating

intercostal nerves

Internal thoracic

artery and vein

FIGURE 10 –2

120 Section II • The Breast

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 sufﬁ cient 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 ﬂ ap 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 ﬂ ap.

◆ 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 sufﬁ cient 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 superﬁ -

cial investing fascia of the breast (Figure 10-4). The thickness of the ﬂ aps 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 paren-

chyma lies closest to the skin at the nipple-areolar complex and increases in thickness toward

the periphery of the breast.

CHAPTER 10 • Modiﬁ ed Radical Mastectomy 121

Incision line for

modified radical

mastectomy

Undermined area

FIGURE 10 –3

Initial incision

being carried out

FIGURE 10 –4

122 Section II • The Breast

2. DISSECTION

◆ Dissection is initiated by elevating the skin edges with skin hooks or Freeman rake retrac-

tors 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 ﬂ aps are elevated, the assistant holds upward tension on the skin ﬂ aps while the sur-

geon uses countertraction on the breast parenchyma. These counter forces help expose the

ﬁ ne 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 superﬁ cial fascia to its fusion with

the muscular fascia around the anatomic borders of the breast. These are deﬁ ned 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 superﬁ cial 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 ﬁ bers to avoid transection of muscle ﬁ bers, 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 deﬁ ned by the pectoral muscles medially, the latissimus

dorsi muscle laterally, the axillary vein superiorly, and the subscapularis and teres major

muscles posteriorly.

CHAPTER 10 • Modiﬁ ed Radical Mastectomy 123

Overlying fascia of

pectoralis major

muscle

FIGURE 10 –5

Incision being carried out

to include axillary region

FIGURE 10 –6

124 Section II • The Breast

◆ 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 pecto-

ral 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 identiﬁ ed coursing transversely below the

axillary vein and should be preserved if free of matted tumor-laden nodes to avoid bother-

some 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 identiﬁ ed 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 conﬁ rmed 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 inser-

tion. The axillary vein overlies the tendinous insertion, and care should be taken to proceed

cautiously from lateral to medial and from superﬁ cial to deep, with careful visualization of

underlying structures.

CHAPTER 10 • Modiﬁ ed Radical Mastectomy 125

Medial anterior

thoracic nerve

(40% lateral to

pectoralis minor

muscle)

Pectoralis minor muscle

Medial anterior thoracic nerve

(60% through pectoralis minor muscle)

Pectoralis major muscle

FIGURE 10 –7

Medial anterior

thoracic nerve

Intercostal brachial nerve

Axillary artery and vein

covered by fascia

FIGURE 10 –8

126 Section II • The Breast

◆ The superior extent of the axillary dissection should begin approximately 5 mm below the

axillary vein to preserve the lymphatics of the arm and reduce the likelihood of upper

extremity lymphedema (Figure 10-9).

◆ Figures 10-9, 10-10, and 10-11 show dissection with exposure of the brachial plexus

above the axillary vein for anatomic orientation, but the dissection should stop just below

the vein. This tissue is rich in lymphatics and blood vessels, which should be ligated with

ﬁ ne silk ties or Weck Hemoclips. Preservation of the lymphatics surrounding the axillary

vein reduces the risk of lymphedema.

◆ The thoracodorsal artery and vein with the thoracodorsal nerve medially will be identiﬁ ed

in the lateral third of the axillary artery (see Figure 10-10). The thoracodorsal trunk courses

on the medial aspect of the latissimus dorsi muscle. Transection of the thoracodorsal nerve

leads to weakened shoulder adduction. Once the thoracodorsal trunk is identiﬁ ed, lateral

dissection is safe as long as the intercostal brachial cutaneous nerve is visualized as it

emerges from the axillary fat pad, approximately halfway up the latissimus dorsi muscle

coursing toward the arm.

◆ Dissection of the axilla is carried out from superior to inferior, maintaining visualization of

the nerves at risk. As the fatty tissue is swept inferiorly, lymphatics and blood vessels are

transected.

Axillary vein

and artery

Lymph nodes

Long thoracic nerve

FIGURE 10 –9