The Use of a DCIA Free Flap with Internal and External Oblique Abdominal Muscle in Compound Oral Cavity Defects: A Pilot Study

Background/Objectives: The deep circumflex iliac artery (DCIA) free flap with internal abdominal oblique muscle (IAOM) is a well-known method of reconstruction used in cases of oral cavity neoplasms. Because the IAOM can be insufficient for extensive defects after removal of advanced carcinomas of the tongue, floor of the mouth, or gingiva, the additional preparation of a perforator-supported external abdominal oblique (EAOM) muscle flap can be useful. The aim of this study was to introduce the use of a DCIA flap with an IAOM and EAOM island in the reconstruction of oral cavity compound defects. Methods: A retrospective analysis was performed involving eight patients who underwent reconstruction using a DCIA free flap with IAOM and perforator-supported EAOM island. Patients underwent the operation between June 2021 and February 2025 in the Department of Maxillofacial Surgery of the Rydygier Hospital in Kraków, Poland. Results: A group of eight patients underwent an operation due to squamous cell carcinoma of the oral cavity. The most common primary subsite of disease was the floor of the mouth (n = 4, 50%), followed by the lower gingiva (n = 2, 25%) and retromolar area (n = 2, 25%). All patients required resection involving part of the mandible, the floor of the mouth, and part of the tongue simultaneously with reconstruction using a DCIA free flap with IAOM and perforator-supported EAOM island. Osteotomies were performed in two flaps (one single osteotomy, one double osteotomy). Reconstruction was successfully performed in seven out of eight patients (overall success rate 88%). Conclusions: The DCIA free flap with IAOM and perforator-supported EAOM flap is a reliable method for compound soft tissue and bone defects in maxillofacial reconstruction. The use of IAOM and EAOM can be helpful in cases of three-dimensional soft tissue defects of the lower gingiva, the floor of the mouth, and the tongue. The lower gingiva and floor of the mouth can be reconstructed with IAOM, while the more mobile part of the tongue can be reconstructed with a perforator-supported EAOM island.