FATE OF THE TRAM FLAP AFTER ABDOMINOPLASTY IN A RAT MODEL

During a classical abdominoplasty, all musculocutaneous perforators fr om the deep inferior epigastric vessels are normally divided. Even if somehow neovascularization could relink the abdominal skin and rectus abdominis muscles, reestablishing these same discrete perforators woul d be unlikely because of the barrier effect of the abdominal wall fasc ia. Therefore, a lower transverse rectus abdominis musculocutaneous (T RAM) flap intuitively should not regain sufficient vascularity for via bility after a prior abdominoplasty, and a history of the latter shoul d be expected to be a major contraindication for this procedure.Nevert heless, anecdotal observations of successful lower TRAM flaps followin g abdominoplasty seem to contradict our basic principles, which may ne ed better further elucidation. Consequently, this two-stage study in S prague-Dawley rats was undertaken, initially performing an abdominopla sty in all rats. This was followed 1 or 10 months later by the creatio n of an unipedicled superiorly based TRAM flap that incorporated virtu ally all of the abdominal skin. From our identical historical TRAM fla p control (n = 5) except without prior abdominoplasty, 72.8 +/- 12.83 percent of this area survived. TRAM flaps raised 1 month after the abd ominoplasty (n = 6) had 2.2 +/- 3.4 percent or essentially no viabilit y. Unexpectedly, the long-term group (n = 7) demonstrated 13.7 +/- 10. 0 percent viability, ranging from 0 to 30 percent. Both groups of TRAM flaps after abdominoplasty had a flap survival area significantly les s than that of the control by two-tailed group t test (p < 0.001), and that of the longterm group area was significantly greater than that o f the short-term (p = 0.022). Lead oxide studies 10 months after abdom inoplasty revealed no irrefutable evidence of the reestablishment of r ectus abdominis perforators to the integument, although obviously some reconnections had formed at the microcirculatory level to partially r evascularize some flaps. The range of viability of the long-term rat T RAM flaps documented that for the majority, surviving surface area was minuscule even following a delay equivalent to a human decade after a bdominoplasty (1 rat month - 1.1 human years), yet rarely sufficient r evascularization did indeed occur, which could explain the prior unusu al clinical successes. However, the basic principle that a TRAM flap r aised following a classical abdominoplasty at any time would he a risk y maneuver seems to still be a valid concept.