Abstract: Objective: To design an improved iliac bone flap with perforator based external oblique abdominal muscle (EOAM) island for monitoring postoperative blood supply and flexible repair of soft tissue defects based on the traditional vascularized iliac flap. Methods: Four patients who required segmental resection and mandibular reconstruction due to tumor or osteomyelitis were selected, the ascending branch was found along the deep circumflex iliac artery (DCIA) and a portion of the external abdominal oblique muscle was dissected as an observation island while harvesting the iliac flap, the DCIA and accompanying veins were routinely anastomosed, followed by fixation using a titanium plate. The free external oblique abdominal muscle was placed outside the submandibular skin as an observation island, and the blood supply of the iliac flap was closely monitored by the blood supply of the observation island. Results: The iliac flap was successful in all four patients. Postoperative monitor of the color, shape, and texture of the observation island allowed judging the blood supply of the DCIA. Conclusion: The improved iliac flap with a perforated EOAM island is worthy of further evaluation and promotion for both reliable monitoring of postoperative blood supply and flexible repair of soft tissue defects.

Key words: flap monitoring, iliac bone flap, observation island, blood supply