Survival of pedicled pectoralis major flap after secondary myectomy of muscle pedicle including transection of thoracoacromial vessels: does the flap remain dependent on its dominant pedicle?

Abstract

The pectoralis major (PM) flap is a frequently used flap for head and neck reconstructions. The muscle is easy to transpose on the dominant thoracoacromial bundle and has relative low morbidity. Some patients complain of pain and restricted neck motion after PM flap transposition. Secondary contraction due to radiotherapy, atrophy or insufficient denervation during transposition can be causes for this function deficit. In a series of ten patients we analysed the causes of this contraction and show the results of secondary myectomy of the PM pedicle with transection of the thoracoacromial bundle. Between 2000 and 2008 a total of 12 myectomies were performed in ten patients. Indication, radiation, denervation of the PM, and follow-up before and after myectomy were analysed retrospectively. Indications for PM flap reconstruction were floor of mouth malignancy, covering of neck wound, (osteo)radionecrosis, and larynx fistula. In six cases the PM muscle was denervated primarily. Seven patients received preoperative radiation on the wound bed. The interval between PM flap reconstruction and myectomy ranged from five months to seven years. There was no (partial) necrosis of the PM flaps after myectomy (median follow-up 15 months). All patients were satisfied with the result of myectomy. Myectomy of the PM pedicle with transection of the thoracoacromial bundle after muscle transposition is an effective method to treat secondary neck contracture. The procedure is safe, regardless of pre- or postoperative radiotherapy. Our results question the general accepted theory that muscle flaps remain dependent on their dominant pedicle.