Anatomical Analysis of the Vascular Distribution in the Pectoralis Major Myocutaneous Flap Using Latex Injection

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Background:Although the free flap has become the first choice in recent head and neck reconstruction, the pectoralis major (PM) myocutaneous flap still plays an important role, especially in salvage operations. However, unstable blood circulation of skin paddle with a higher partial necrosis rate has previously been reported.Aim and Objectives:In this current study, we tried to clarify the blood supply of the pectoralis major myocutaneous flap and to determine whether it can be harvested as a pedicled perforator flap.Materials and Methods:The 6 sides of 3 fresh frozen cadavers were examined in this study. The pectoral branch of the thoracoacromial artery was dissected out and injected with colored latex. In the first step, the pectoralis major muscle was elevated from the thoracic cage and the characteristics of the encountered muscular perforators were recorded. Following that, the skin flap was separated from the underlying muscle and the cutaneous perforating branches were also documented.Results:The circulation of the pectoralis major muscle has two main territories. It receives blood supply from pectoral branch of the thoracoacromial artery in the cranial portion and from multiple perforating intercostal branches in the caudal portion. These two territories are linked by choke vessels mainly at the level of fourth costal cartilage. The perfusion of the distal flap is maintained by muscle body containing these choke vessels. However, the number of perforating branches to the skin paddle is much smaller than that to the pectoralis major muscle and their locations vary individually, so the perfusion of the skin is unreliable in the absence of these perforators.Conclusion:The blood circulation of the skin paddle of the pectoralis major myocutaneous flap is unstable because of variation in the number and location of perforating vessels present and also the relative paucity of the cutaneous perforating branches. When designing a skin island, especially a small one, great efforts must be made to include either the third perforating branch of the internal mammary artery or the major intercostal perforating branches to improve blood flow. Hand-held Doppler may be helpful in localization of these vessels. (J Taiwan Soc of Plast Surg 2011; 20: 266~273)