Intraoperative vascular monitoring of ipsilateral vs. contralateral TRAM flaps

Transverse rectus abdominis musculocutaneous (TRAM) flap breast reconstruction has become an increasingly common procedure in the 1990s. The original description of the procedure was that of an ipsilaterally based pedicled procedure. However, because of concerns about potential folding of the pedicle with possible compromise of the vascular supply, with full muscle harvest the contralateral flap soon became the flap of choice. Subsequently there have been several large clinical series of pedicled TRAM flaps reported showing a relatively high complication rate related to problems with flap vascularity. These findings resulted in many centers favoring free TRAM flap breast reconstruction, despite an increased resource utilization and negligible differences in complication rates. Ipsilateral pedicled TRAM flap breast reconstruction is not a commonly reported procedure, and is reserved for patients in whom scars preclude use of the contralateral pedicle. The ease of flap shaping and lack of tension on the pedicle is recognized by some, and the ipsilateral procedure has become the flap of choice for these surgeons. The authors hypothesized that ipsilateral TRAM flaps have less compromise of venous outflow as a result of the rotational tension effect of transposing the flap to the mastectomy site. To determine if the vascularity of the pedicled TRAM procedure is influenced by pedicle choice, an intraoperative clinical study was designed to compare intravascular pressures in the deep inferior epigastric artery and vein pedicle at various times from pedicle division to flap insetting. Ten consecutive ipsilateral TRAM flaps were compared with eight contralateral flaps. The deep inferior epigastric pedicle was cannulated with both an arterial and venous catheter, and pressures were monitored from the time of division of the inferior pedicle through to the time of flap insetting. The venous pressures of the contralateral flaps were significantly higher at flap rotation and flap insetting compared with the ipsilateral group (p = 0.014 and p = 0.022 respectively). Perfusion pressures showed a greater decrease in the contralateral group from the time of pedicle division to the point of flap rotation and flap insetting compared with the ipsilateral group (p = 0.081 and p = 0.055). The authors conclude that pedicle tension in contralateral TRAM flaps is more common and results in greater venous resistance and decreased perfusion pressures. Versatility in flap shaping, improved maintenance of the IMF, and lack of disruption of the natural xyphoid hollow gives ipsilateral TRAM flaps additional advantages.