A rat transverse rectus abdominis musculocutaneous flap model: effects of pharmacological manipulation.

A study was designed to attempt to develop an experimental animal model for the transverse rectus abdominis musculocutaneous (TRAM) flap. The rat has a well-formed superior epigastric artery with musculocutaneous perforators that have been shown to support a musculocutaneous flap on a single superior pedicle. Despite the anatomical differences between the dominance of the axial longitudinal cutaneous circulation in loose-skinned animals compared with humans, as well as a dominant superior intramuscular pedicle, the rat TRAM model appears to be reproducible and has predictable zones of viability as well as areas that typically do not survive when based on a single superior pedicle. These areas of nonviability correspond to those zones at high risk of nonviability in the human clinical situation: zone 3 and 4 on the contralateral side and zone 3 on the ipsilateral side (tissue lateral to the superficial inferior epigastric supply). Once the reliability and reproducibility of this model was demonstrated (coefficient of variation 18.9%), a study was undertaken to determine whether pharmacological manipulation of this flap altered survival in those areas that are inadequately perfused. The two agents tested were allopurinol (xanthine oxidase inhibitor, antioxidant) and pentoxifylline (microcirculatory rheological agents that is a xanthine analogue and is also believed to have antioxidant potential). The study involved creating right unipedicled TRAM flaps in 30 male specific pathogen-free Sprague-Dawley rats weighing 375 to 450 gm. The transverse skin paddle was centered over the umbilical dimple and measured 5.5 x 2 cm.(ABSTRACT TRUNCATED AT 250 WORDS)