Sir: Medial row perforators are essential for maintenance of adequate perfusion to zone IV of the pedicled transverse rectus abdominis musculocutaneous (TRAM) flap. A posterior dissection of the anterior rectus sheath toward the midline can facilitate visualization and preservation of these perforators, which are often inadvertently sacrificed during flap harvest. The senior author (J.A.A.) has successfully used this posterior approach technique in 253 consecutive pedicled TRAM flaps with no flap losses. In many of these flaps, zone IV was successfully preserved. The flap is raised on both sides beginning laterally, with careful dissection up to but not crossing the abdominal midline on the side contralateral to the pedicle. On the ipsilateral side, careful dissection proceeds until lateral perforators are identified. The anterior rectus sheath is then divided longitudinally just lateral to this lateral row of perforators, and the rectus muscle is isolated along its lateral edge. The rectus muscle is then elevated off the posterior rectus sheath beginning at its lateral edge until the linea alba is visualized. From its deep side, the anterior sheath is then dissected free from the rectus muscle going laterally from the midline until the medial perforators are clearly seen. These perforators are usually found anywhere from 1 or 2 mm to approximately 1.5 cm lateral to the linea alba. The anterior rectus sheath is then incised longitudinally from its posterior aspect, just medial to the medial perforators (Fig. 1). This dissection continues cranially from the inferior border of the flap, with continued preservation of the medial perforators exiting the rectus muscle medially and piercing the anterior sheath near the linea alba (Fig. 2).Fig. 1.: Anterior rectus sheath being incised after the medial perforators have been identified along its posterior surface. Note easily visible perforator near tip of dissecting scissors.Fig. 2.: Diagram of the described posterior approach of TRAM flap dissection, showing preservation of lateral and medial row perforators.Perfusion of the TRAM flap can be described in four zones, with zone IV representing the least well-perfused section, farthest from the vascular pedicle of the flap, and contralateral to it.1 During flap elevation and dissection, many surgeons routinely divide and discard this segment because of its poor vascular quality. Preservation of appropriate blood flow to zone IV ensures a more reliable and larger flap, and may reduce the incidence of ischemia-related flap complications. The highest concentration of perforators to the TRAM flap is near the umbilicus. Once these perforators have exited the rectus muscle, however, they often undertake a transverse course before piercing the anterior rectus sheath.2 Understanding the location of these perforators is important in preventing their inadvertent transection. Although the nervous supply to the flap more consistently accompanies the lateral row of perforators, it is the medial row that mainly supplies perfusion to the contralateral side of the flap.3,4 As has been documented in anatomical studies, some medial perforators are easily identified on the posterior aspect of the sheath as they pierce through it, but they become difficult to see on its anterior surface once they have experienced significant changes in diameter and/or orientation.5 We therefore suggest a posterior approach to the dissection of the rectus abdominis muscle during TRAM flap harvest, as we find that it facilitates adequate visualization and preservation of these crucial medial row perforators. DISCLOSURE No funds were obtained to support this work. The authors have no financial interest to declare. Sophie Bartsich, M.D. Jeffrey A. Ascherman, M.D. Division of Plastic Surgery Department of Surgery Columbia University Medical Center New York, N.Y.
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Jan 1, 2013
J Boehmler 
Open Access