The iliacus muscle flap: an anatomical and clinical evaluation.

BACKGROUND The iliacus muscle is proposed as a new solution for coverage of small to medium defects where either a bulky flap or conspicuous donor sites are undesirable. METHODS Dissection and Microfil studies were performed on fresh cadavers to define the gross and microvascular anatomy of the muscle. Live evaluation of the muscle was performed in combination with multiple iliac crest free tissue transfer procedures. The muscle was then used as a free flap in four separate cases to cover difficult extremity wounds. It was used as a pedicled flap in conjunction with a free iliac crest in a fifth case to assist with a composite mandible and facial defect. RESULTS The iliacus originates from the inner aspect of the iliac crest and then fuses with the psoas at the level of the inguinal ligament. Its primary blood supply derives from a large branch off of the deep circumflex iliac artery. The isolated muscle resulted in a pancake-like flap measuring approximately 8 × 8 cm with a 6- to 8-cm pedicle (deep circumflex iliac artery). The muscle was then used clinically both as isolated free flaps and as a pedicled flap in conjunction with a free iliac crest. All flaps survived, resulting in healed wounds without complication. CONCLUSIONS These results demonstrate that the iliacus is a new muscle that should be added to the microsurgeon's choices for free tissue transfer. It is easily harvested, has a large and well-defined pedicle, and is less prone to donor-site complications than some other muscles typically used for free tissue transfer.