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.