Pectoralis Major Musculocutaneous Flaps in Head and Neck Surgery

Introduction

Regional flaps play an important role in reconstructive surgery of the head and neck. Introduced in 1979, the pectoralis major musculocutaneous flap was an important improvement over the deltopectoral flap and multistage tissue transfers that had dominated the reconstruction attempts previously. This flap allowed effective and more reliable single-stage tissue transfer for reconstruction of complex defects of the neck and face, upper aerodigestive tract, and skull base. This development enhanced resection capability and enabled patients with cancer of the head and neck to receive timely adjuvant radiation therapy, facilitating surgical treatment combined with curative intent. However, with advances in microvascular tissue transfer, the pectoralis major flap has been relegated to a secondary role in reconstruction. Nevertheless, the pectoralis major flap remains an important reconstructive option for certain indications.

Key Operative Learning Points

• 1.

  The role of the pectoralis major musculocutaneous flap in contemporary head and neck reconstruction lies in the salvage of patients who are not candidates for free flaps or for coverage of the neck when a free flap is deemed unwarranted.

• 2.

  The flap is based on the pectoral branch of the thoracoacromial trunk. The trunk originates from the subclavian vessels and emerges at the point projected on the skin just medial to the deltopectoral triangle bordered by the deltoid, pectoralis major, and clavicle (also known as the Mohrenheim fossa). The pectoral branch runs along a line drawn from that projected point to the xiphoid process ( Fig. 170.1A ). The pedicle runs on the undersurface of the pectoralis major muscle ( Fig. 170.2B ) in the clavipectoral fascia and must be visualized and protected during dissection.

  
  

• 3.

  Dissection of the flap should be performed with minimal muscle bulk ( Fig. 170.3 ) and, when necessary, comprising the entire muscle. Complete denervation of the muscle included in the flap is important to prevent subsequent animation of the flap and to promote atrophy.

  

• 4.

  The skin paddle is often designed on the inferior border of the muscle or inframammary fold in women (see Fig. 170.3 ); its perimeter can be used as the exposure for flap dissection (see Fig. 170.1A ). Distal location of the skin paddle improves the arc of rotation.

• 5.

  A minimal-access dissection of the flap through the perimeter of the skin paddle is best performed with the use of lighted retractors. Complete hemostasis and secure ligation of the deltoid and acromial branches of the thoracoacromial trunk are the key. A laparoscopic harmonic scalpel is an excellent adjunct in this dissection (see Fig. 170.1C ).

Preoperative Period