What is a modified radical mastectomy performed?

Updated: Jun 18, 2021
  • Author: Nafisa K Kuwajerwala, MD; Chief Editor: Erik D Schraga, MD  more...
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The anatomy of the breast and its boundaries include the clavicle superiorly, the sternum medially, the inframammary fold inferiorly, and the latissmus along the pectoralis major fascia laterally. The total mastectomy involves removal of the entire mammary gland including the nipple-areolar complex and pectoralis fascia.

In a simple mastectomy with no immediate reconstruction, the outline of the breast is marked and the medial and lateral endpoints of the breast are marked. The breast is then pulled downward and a horizontal line connecting the two endpoints is drawn to mark the upper incision. The breast is then pulled up and a second line connecting the endpoints is drawn to identify the lower incision. These lines form an ellipse around the nipple and can be adjusted to include prior incisions. See the image below.

Anatomy markings prior to mastectomy. Anatomy markings prior to mastectomy.

These markings are checked to confirm that there is adequate skin for closure with minimal tension. The skin is then incised.

The next step is to make viable skin flaps that leave subcutaneous tissue and superficial vasculature but do not compromise the need to remove the entire mammary gland. These flaps are approximately 5 mm in thickness. The plane is identified by careful retraction with skin hooks and adequate countertraction, allowing the surgeon to identify the avascular plane (superficial breast fascia) between the breast and subcutaneous tissue. Either a knife, scissors, harmonic scalpel, or electrocautery can be used, depending on the surgeon’s preference.

Tumescent solution of dilute epinephrine hydrochloride in lactated Ringer solution is commonly used in association with liposuction. [20] The solution is infused into the avascular plane to facilitate dissection and minimize blood loss during the surgery.

The flaps are raised to the borders of the breast as previously defined. The pectoralis fascia is divided both superiorly and medially. The pectoralis fascia is removed with the breast; muscle should only be removed when there is gross involvement. The dissection proceeds to the lateral edge of the pectoralis. See the images below.

Superior flap dissection. Superior flap dissection.
Superior flap dissection up to the pectoralis musc Superior flap dissection up to the pectoralis muscle facia.

Depending on surgeon preference, the breast may now be completely removed or axillary dissection may continue, allowing the breast to give gravity traction and assist with exposure. See the image below.

Lifting the breast off the pectoralis muscle with Lifting the breast off the pectoralis muscle with the facia in the specimen.

The axillary lymph node dissection follows the borders of the axilla and includes level I and II lymph nodes. The axilla is bordered by the axillary vein superiorly, the latissimus dorsi laterally, pectoralis muscle medially, and the serratus muscle anteriorly.

When performing an axillary dissection with a simple mastectomy, a separate incision is not required. However, if a skin-sparing mastectomy is performed, a separate incision may be needed.

The axilla is first entered by opening the clavipectoral fascia. See the image below.

Entering the axilla at the lateral boder of pector Entering the axilla at the lateral boder of pectoralis major muscle.

The axillary vein is identified by locating the lateral border of the pectoralis major; the vein is identified as it runs posterior to the pectoralis muscle with careful blunt dissection and retraction inferiorly of the axillary contents. Once identified, lymphatics can be tied, clipped, or cauterized, depending on surgeon preference.

After the vein is identified, careful steps are taken to preserve its branches; the thoracodorsal bundle is identified as it runs in the axillary fat pad and then enters the latissimus dorsi. The long thoracic nerve should be preserved; it runs medial to the thoracodorsal bundle and is identified close to the chest wall posteriorly. See the image below.

Preserving the axillary vein and the thoracodorsal Preserving the axillary vein and the thoracodorsal nerve (along with the thoracodorsal vascular bundle) to the latissimus dorsi and serratus anterior in the axillary dissection.

Once these nerves and vein are identified, the axillary contents are dissected off the thoracodorsal bundle superiorly and medially up to the level of the axillary vein. The contents are then retracted inferiorly, the medial attachments to the serratus muscle are divided, and the specimen is handed off.

Once the axillary dissection is completed, two drains are placed: one in the axilla and one anterior to the pectoralis muscle. Drains should be shortened to allow for placement of the drain within a pocket for patient comfort and to avoid clotting in the tubing. The skin is then closed in an interrupted or running fashion according to the surgeon’s preference. See the image below.

Drain placement and skin closing after mastectomy. Drain placement and skin closing after mastectomy.

Patients are normally discharged the next morning and drains are removed when the output is less than 30 mL in a 24-hour period. Patients are encouraged to ambulate early and begin arm stretches.

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