Management of the axilla

Technique

The contents of the axilla lie deep to the clavipectoral fascia, and are divided into three levels, based on their relationship to the pectoralis minor muscle (see Anatomy, Chapter 1 ). Level I is lateral to the muscle and contains the most lymph nodes, and usually the sentinel lymph node(s). Level II nodes lie behind the pectoralis minor, and Level III is medial to it. Axillary clearance aims to remove the lymph nodes and surrounding axillary fat from at least levels I and II. Level III nodes can also be removed if they are thought to be involved at surgery.

Axillary clearance typically involves making a separate incision in the axilla when breast conservation or nipple-sparing mastectomy is performed. In cases of a conventional mastectomy, the axillary clearance can be performed through the lateral extent of that incision. After raising skin flaps, the clavipectoral fascia is incised to enter the axilla proper. The axillary contents are typically mobilised off the chest wall lateral to the pectoralis major muscle using a combination of blunt dissection and ligation of small lymphatics and veins with electrocautery. It can be helpful to have an assistant retract the pectoralis muscle medially. Larger veins and lymphatics should generally be clipped and ligated. The medial pectoral nerve wraps around the lateral edge of the pectoralis major muscle and should be preserved when possible. Other important structures to identify and preserve include the thoracodorsal bundle, which contains an artery, vein and nerve and lies anterior to the latissimus muscle, which they supply. The long thoracic nerve runs along the chest wall and innervates the serratus anterior muscle. Intercostobrachial nerves are located in a more anterior position and run obliquely, providing sensation to the upper inner arm. Finally, the axillary vein is at the top of the field, and is the superior limit for most axillary dissections. At the conclusion of the dissection, one should generally re-examine the cavity for any residual palpable adenopathy, and examine the space between the pectoralis major and minor adjacent to thoraco-acromial vessels for any palpable nodes and remove them.

Most surgeons leave a drain in the axilla after the axillary dissection is completed, to prevent accumulation of serous fluid and blood postoperatively. These can be removed after 24 hours although some prefer them to remain until less than 50 or 30 ml output per day. Patients can be discharged with the drain. Increasingly after axillary dissection the axillary space is being closed by a series of quilting sutures. By using using a barbed continuous suture this decreases the time required to place these sutures and allows multiple small quilts to be placed without tension. After such quilting drains are not always required.

Complications

Axillary dissection has several known complications, including lymphoedema, limitations in postoperative shoulder and arm mobility, prolonged postoperative pain, cording (Mondor’s disease) and paraesthesia. Inadvertent injury to the long thoracic nerve causes winged scapula due to weakness of the serratus anterior muscle. In the case of damage to the thoracodorsal bundle, weakness of the latissimus muscle ensues, with weakness of the arm with respect to extension, adduction and medial rotation. Injury to the intercostobrachial nerve results in sensory deficit in the upper inner arm.

For many patients, lymphoedema is the most dreaded complication, and efforts to reduce the risk and/or modify the course and progression of the disease continue. Generally speaking, the incidence of self-reported lymphoedema after axillary dissection is about 15%. This risk is higher if axillary radiation is administered postoperatively. Several recent studies suggest that subclinical lymphoedema is far more common among patients undergoing axillary surgery than once appreciated. Data from the ALMANAC trial reported 12-month incidence of lymphoedema of 5% with sentinel lymph node biopsy alone versus 13% with axillary clearance. Exercise is not harmful, and in fact, some data suggest that lifting weights may be helpful in reducing lymphoedema. Otherwise, treatment for lymphoedema is generally supportive, with physical therapy, arm strengthening, and stretching; compression garments for the arm and hand may be helpful in severe cases. Further information on lymphoedema management can be found in chapter ….

Mondor’s disease or syndrome, or cording of the axilla and upper arm, is a self-limited, harmless condition. Cording can also be observed running longitudinally down the anterior chest wall, below the breast. It is typically observed within a couple of months after surgery of the breast and/or axilla. It is believed to be caused by thrombosis in subcutaneous veins and ligation of veins after axillary dissection. Patients may experience pain and/or tenderness in the area, but can be reassured that the condition will subside with time. Warm compresses and non-steroidal anti-inflammatory drugs can be helpful.

Shoulder dysfunction and limitations in range of motion may also be observed after axillary dissection. ^, Rehabilitation with physical therapy, stretching, strengthening, etc. are the mainstay of treatment, although symptoms may persist for at least a year after surgery. The presence of positive axillary nodes and higher body mass index appear to place women at higher risk for dysfunction, and early intervention for those at high risk should be considered.

Targeted axillary dissection

More recently, the concept of targeted axillary dissection (TAD) has become popularized particularly in patients who, prior to neoadjuvant chemotherapy, had a suspicious lymph node on ultrasound that was biopsied, marked and found to be positive. In order to minimize the false negative rate of sentinel node biopsy alone after neoadjuvant therapy targeted axillary dissection aims to remove remove the marked node that was found to be involved at diagnosis as well as any sentinel lymph nodes, after neoadjuvant therapy. A variety of techniques can be used to mark the involved node at diagnosis including metal clips, radioactive seeds, magseeds, radiofrequency tags and Savi scouts.