10 Internal Mammary Artery Perforator Flap

Abstract

Reconstructive surgery evolved as a result of the enormous numbers of World War I and II victims, long before profound knowledge of the vascularity of flaps was present. Sophisticated imaging techniques have given us at present a thorough understanding of the vascularity of tissues so that randomly vascularized fasciocutaneous flaps used a century ago evoluted into the perforator flaps we use today. The actual concept of vascularity of skin perforator flap is that a main source artery supplies a skin region with one or more perforators which may be musculocutaneous, septocutaneous or following a direct course to the skin. The internal mammary vessels send off perforators through the intercostal muscles and the pectoralis muscle to supply the skin of the anterior chest wall. Based on this information we investigated the possibilities to use the anterior chest wall skin as a flap for head and neck reconstruction. In a cadaver study we found that that the dominant perforator of the internal mammary vessels supplies a large territory of the anterior chest wall skin. Additional injection of the non-dominant perforators did not lead to any substantial enlargement of this territory. In a second cadaver study the anatomy of the internal mammary vessels and it's perforators was studied. The mean length of 27 dominant perforators was 47 mm. By removing cartilage from the second rib, the mean length of the vascular pedicle enhanced up to the level of the first rib, could be doubled to 92 mm when based on the second perforator. This outcome supported the feasibility of the flap as a pedicled flap in head and neck reconstruction. Enhancement of the vascular pedicle by mobilisation of the internal mammary vessels, combined with the large skin territory leads to an arc of rotation that even high located defects in the upper head and neck can be reached. We report on the successful clinical use of a pedicled internal mammary artery perforator (IMAP)flaps in seven head and neck reconstructive cases. In an other study we report on the clinical use of three free IMAP flaps. All of these flaps healed without complications and all donor sites could be closed primarily. Our experience indicates that the pedicled as well as the free IMAP flap is a valuable alternative and should be available in the armamentarium of every head and neck reconstructive surgeon. Proper planning of an IMAP pedicled or free flap includes preoperative assessment of the internal mammary perforators, primarily to distinguish the dominant perforator in cases where the flap can be vascularized by one perforator only. Laser-Doppler flowmetry, intraluminal arteriography, CT-angiography or MR-angiography is used for such assessment. In a radiological study we showed retrospectively that previous diagnostic examinations was available and informative regarding the level of the dominant perforator. Therefore we advocate re-assessment of such previous examinations before ordering additional angiography and suggest to include the parasternal region in diagnostic scans.