The versatility of the pectoralis major flap in reconstructive surgery

Abstract

Background The pectoralis major flap is frequently being applied as a pedicled flap for head and neck reconstruction. To reduce donor-site morbidity, muscle-preserving methods using only a segment of this muscle for transplantation, were described. The nerve supply to the clavicular part of the pectoralis major muscle was investigated in order to maintain its function at the donor site. This function and the clinical outcome at the receptor site were tested postoperatively. To determine its feasibility as a segmental microsurgical free flap, the length and diameter of the vascular pedicle of the pectoralis major muscle were investigated next. Finally, our clinical experience with this free flap was presented. Materials and methods Surgically relevant features of the clavicular part of the pectoralis major muscle and its nerve supply were studied by anatomical dissections on formalin-fixed and fresh cadavers. A new surgical technique was then clinically applied for head and neck reconstruction. Postoperatively, muscle activity of the remaining clavicular and abdominal muscle parts was determined objectively and subjectively. The overall rate of complications, major complications, and the final outcome at the receptor sites were studied after 54 pedicled segmental pectoralis major island flaps. Possible risk factors were assessed. Seventeen anatomical dissections of the vascular pedicle were performed in formalin-fixed cadavers to determine its feasibility as a segmental free flap. The length of the pedicle, its arterial diameter, and its entry point into the muscle were noted. Segmental pectoralis major free flaps were then clinically applied for reconstruction of craniofacial defects in five patients. Results A separate nerve innervates the clavicular and upper medial sternocostal parts of the pectoralis major muscle. Based on our anatomical findings we proposed a surgical technique for transfer of the pectoralis major island flap through a tunnel in the deltopectoral groove. Postoperatively, the electromyogram proved preservation of innervation of 16 of the 17 clavicular parts. Complications at the receptor site were observed after 21 of the 54 operations (0.39). Eleven of these cases (0.52) required repeated surgery. Final outcome was successful in 49 of the 54 operations (0.91). The length of the vascular pedicle of the sternocostal part was 6.6 cm. The external arterial diameter was 1.8 mm. This entry point was located a mean of 8.8 cm caudal to the clavicular line. After application as a free flap in five patients, total flap loss occurred in one patient and repeated surgery was required in another. Final flap outcome was favorable in four patients. Conclusions Transfer of the pectoralis major island flap to the head and neck area through a tunnel in the deltopectoral groove is a muscle-preserving procedure that maintains maximal donor-site function and morphology. This technique is reliable with clinical results comparable to conventional techniques, in addition to function preservation at the donor site. The length and arterial diameter of the vascular pedicle of the sternocostal part are sufficient for microvascular anastomosis. The segmental pectoralis major free flap is a useful and justifiable adjunct to the microsurgical armamentarium for flat or wide craniofacial defects.