How is axillary dissection performed?

Updated: Mar 11, 2019
  • Author: Hemant Singhal, MD, MBBS, MBA, FRCS, FRCS(Edin), FRCSC; Chief Editor: Erik D Schraga, MD  more...
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Axillary dissection can be carried out through the incision for a mastectomy. Patients having lumpectomy usually require a separate incision in the axilla. Often, the preference is for a skin crease incision just below the axillary hairline extending from the posterior edge of the pectoral fold to the posterior axillary line. Flaps are raised off the skin and subcutaneous tissue.

Dissection is carried past the edge of pectoralis major muscle. Retraction of the pectoralis major medially exposes the pectoralis minor and the clavipectoral fascia. The lateral pectoral nerve bundle is identified and preserved. Incision into the clavipectoral fascia allows entry into the axillary fat and the contained nodes. These are removed en bloc through the surgery.

Dissection is carried superiorly along the edge of the pectoralis minor to reach the inferior edge of the axillary vein. Once the axillary vein is identified, this is followed medially to reach the axillary apex, where the axillary vein crosses the lateral border of the first rib.

The axillary contents are then separated from the lateral thoracic wall, which is the medial boundary of the axilla. This exposes the long thoracic nerve, which supplies the serratus anterior muscle (injury to which would lead to winging of the scapula). During this dissection, branches of the intercostobrachial nerve will be identified as they cross the axilla after emerging from the intercostal spaces. The larger trunks should be preserved if possible.

Ligation and division of the smaller tributaries of the axillary vein as they enter the axilla allows visualization and identification of the subscapular vessels and thoracodorsal nerve as they reach the subscapular and latissimus dorsi muscles posteriorly.

The axillary fat and nodal tissue between the long thoracic nerve and the subscapular vascular bundle is carefully dissected. Often, this is performed en bloc with the specimen, although it sometimes can occur separately if there is extensive nodal involvement.

The dissection then proceeds towards the apex to include the nodes medial to the pectoralis minor (Berg level III). This is facilitated by flexion of the free draped arm at the shoulder.

The axillary fat and nodes are finally separated from the axillary tail of the breast to allow the specimen to be excised.

Careful pathological examination for an axillary dissection will often reveal in excess of 20 lymph nodes.

The wound is closed in layers over a suction drain.

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