Leveling the Maxillary Occlusal Plane Without Orthodontic Appliances in Patients With Hemifacial Microsomia Using Unilateral Vertical Mandibular Distraction Osteogenesis

Purpose To assess maxillary occlusal plane correction in patients with hemifacial microsomia (HFM) after vertical vector mandibular distraction osteogenesis (vMDO) without orthodontic appliances. Methods A retrospective study was performed on consecutive patients with HFM and Kaban-Pruzansky type-II mandibular deformities who underwent unilateral vMDO by a single surgeon over an 18-month period. Patients with 12-months minimum clinical follow-up and postero-anterior (PA) cephalograms taken preoperatively and at a minimum of 3 months post-consolidation were included. Results Five patients met inclusion criteria, 3 were female, median age was 13 years, median distraction length was 21.3 mm. Median radiographic follow-up was 5 months (range 3-38) post-consolidation. Median correction of the ramus height differential (difference between non-diseased and diseased side) was 97.3%. Median maxillary height differential correction was 72.2%. Median maxillary occlusal plane angle correction (towards zero) was 84.2%. Relative and absolute maxillary bone growth was greater on the diseased side (median 7.4%, 3.5 mm versus 2.8%, 1.4 mm). Dentoalveolar height decreased bilaterally in 4 of the 5 patients. Median chin point correction (towards midline) was 31.4%. Conclusion Unilateral vMDO without orthodontic appliances effectively corrected mandibular ramus height, leveled the maxillary occlusal plane, and preferentially increased maxillary bone growth on the diseased side in patients with HFM.