Pectoralis Major Myocutaneous Pedicled Flap

Description:

The pectoralis major myocutaneous flap is a large, easily accessible pedicled flap that is based on the pectoral branch of the thoracoacromial artery and may be rotated superiorly to fill defects of the neck, lower face, or oral cavity.

Indications for Surgery:

Large soft tissue defect of the neck, lower face, oral cavity, or oropharynx.

Contraindications to Surgery:

Medical comorbidities that would preclude surgical or anesthesia risk
Congenital or acquired (e.g., traumatic, iatrogenic from axillary node dissection or breast surgery) absence or deformity of the pectoralis major muscle or its blood supply.
Inadequate length of the flap to reach the donor defect.
Primary closure of the chest defect after the flap has been rotated results in some restriction of chest expansion; this may rarely be a problem in patients with limited pulmonary function.

Pre-Operative Evaluation:

No imaging is typically necessary prior to surgery.
The chest wall and axilla should be evaluated for scars that may reveal injury to the thoracoacromial artery.
Examination should document the presence of pacemakers and port-a-caths in the chest wall; harvesting the contralateral side may be considered in these cases.
Gross measurement of the pectoralis length from the clavicle to the inferomedial edge of the muscle can be used to assess reach into the anticipated defect.

Anesthesia:

General endotracheal

Surgical Technique:

The patient is placed supine on the operating table and general anesthesia is induced via endotracheal intubation.
The chest is prepped from the midaxillary line to beyond the midline, and inferiorly to below the costal margin. The area is covered with a sterile drape until the tumor excision portion of the procedure has been carried out.
Once the defect is ready for reconstruction, attention is turned to the chest. The incisions and skin paddle are marked. More than 50% of the skin paddle must overlie any portion of the pectoralis major to ensure the harvest of adequate perforators. In men, the typical paddle is designed at the inferomedial border of the muscle. In women, the skin paddle may be designed in the inframammary crease to avoid breast asymmetry.
A skin incision is made, beginning at the lateral portion of the skin paddle and extending superolaterally parallel to the clavicle. The incision should never approach the clavicle as this may violate the blood supply to the deltopectoral flap, which can be used as a potential salvage reconstruction in the future. The incision is made above the nipple in men and below the breast in women.
The incision is carried down to the pectoralis muscle, and the borders of the muscle are identified.
The incision is completed and the skin island is sutured to the fascia of the muscle before the muscle is lifted off the chest wall in order to avoid shearing of the perforators (preventing devitalization of the skin) during flap handling and delivery into the neck.
The pectoralis major muscle flap is elevated from the chest wall in an inferior-to-superior fashion. The perforator vessels from the chest wall are ligated or clipped.
After the thoracoacromial artery is identified on the deep surface of the muscle, the humoral attachments of the muscle are divided.
A tunnel is created superficial to the pectoralis major fascia, extending superiorly from the upper skin incision to travel subcutaneously over the clavicle and into the neck. This tunnel needs to be sufficiently wide to avoid compression of the main pedicle.
The flap is passed through this tunnel, taking care to avoid shearing of the perforators to the skin paddle.
The flap is inset within the defect with a single layer closure.
The chest is carefully inspected for hemostasis. Suction drains are placed in the wound bed, and the defect is closed primarily in layers, undermining adjacent tissue as necessary.
Viability of the flap is checked again, and care of the patient is returned to the anesthesiologist for extubation and recovery.

Post-Operative Care:

An oncologic procedure with reconstruction via pectoralis major myocutaneous pedicled flap requires a postoperative inpatient stay.
The postoperative examination should assess flap viability by checking capillary refill time of the skin paddle.
Compression of the neck in the region of the pedicle should be avoided at all times. This includes avoidance of circumferential tracheostomy ties, gown ties, or dressings. The patient should be positioned with the head elevated.
Drain output is monitored, and drains are removed when output has decreased sufficiently.
Antibiotic ointment may be applied to incisions three times daily.
If medically stable, the patient is discharged when all drains have been removed and appropriate home care arrangements have been made (if necessary).

Complications:

Bleeding, hematoma, hemothorax, or seroma
Flap ischemia or necrosis
Wound infection or abscess
Suture line dehiscence
Fistula formation