The superiorly based rectus abdominis flap: predicting and enhancing its blood supply based on an anatomic and clinical study.

A detailed investigation of the blood supply of the superiorly based rectus abdominis muscle flap and the transverse rectus abdominis musculocutaneous flap was done to improve the understanding of variations in flap viability and to explain the survival of the flap after internal mammary artery division and radiation. The study involved dissections of the internal mammary and superior epigastric systems, evaluation of pertinent angiograms, and impressions from observations of the vascular anatomy correlated with flap survival in over 600 clinical dissections. There is a diffuse intrathoracic collateral network involving the internal mammary system, with multiple branches and intercommunications on the same side, as well as across the midline. This enhances flap predictability and survival in some patients with internal mammary artery division or compromise. There is also a laterally based blood supply to the flap from the costomarginal artery at the costal margin which is sometimes well developed and may prevent flap compromise if preserved.