Outcome of Distraction Osteogenesis for Mandibular Reconstruction in Patients with Hemifacial Microsomia at University of Benin Teaching Hospital

Hemifacial microsomia (HFM) is one of the most common congenital craniofacial anomalies, characterized by unilateral underdevelopment of the mandible, ear, and facial musculature. Distraction osteogenesis (DO) offers a gradual, biologically driven approach to mandibular elongation, reducing the risk of relapse associated with conventional osteotomy in growing patients. This prospective study evaluates the clinical outcomes of mandibular distraction osteogenesis for skeletal correction in patients with HFM at the University of Benin Teaching Hospital (UBTH), South South Nigeria, over a six-year period from 2018 to 2023. Seventeen patients aged 4 to 18 years who underwent mandibular DO using a unilateral distractor were followed through the activation, consolidation, and postoperative retention phases. Outcome measures include mandibular length gain, facial symmetry assessment using standardized photographs, occlusal change, device-related complications, and relapse at 12-month follow-up. Results indicate a mean mandibular length gain of 18.3mm, with clinically significant improvement in facial symmetry in 14 of 17 patients. Complications included pin site infection in 3 patients and distractor device loosening in 2 cases. A 12-month relapse rate of 17.6% was observed, predominantly in patients who discontinued retention appliance use early. The study contributes the first prospective Nigerian institutional data on DO for HFM and recommends standardized patient selection and retention protocols at UBTH and affiliated maxillofacial centers in the South South zone. Keywords: hemifacial microsomia, distraction osteogenesis, mandibular reconstruction, UBTH, congenital craniofacial.