Cephalometric Improvement Of Severe Microretrognathia With An Anterior Open Bite Using Curvilinear Mandibular Distraction Osteogenesis

Curvilinear mandibular distraction osteogenesis (MDO) provides for multidimensional augmentation and rotation in mandibles with complex, abnormal morphology. This study aims to demonstrate cephalometric changes after curvilinear MDO.A prospectively maintained craniofacial database was queried for patients undergoing curvilinear MDO from 2009 to 2015. Demographic and operative data were collected. Cephalometric measurements were obtained from preoperative and postdistraction imaging, including sella-nasion-B point angle (SNB), mandibular plane angle (MPA), occlusal plane angle (OPA), and gonial angle (GA). Measurements were compared using a paired t test.Nine patients exhibiting microretrognathia and an anterior open-bite deformity had a mean age of 8.46.0 years and a mean follow-up of 23.2 +/- 25.3 months. Mean distance distracted was 32.6 +/- 7.2mm, with augmentation in length and height, and rotatory closure of anterior open bites. Preoperative SNB versus postdistraction was 66.9 +/- 4.2 versus 78 +/- 9.1 degrees (P=0.0029). MPA, OPA, and GA all decreased (61.0 +/- 10.7 vs. 45.7 +/- 11.1 degrees, P=0.0066, 37.3 +/- 8.9 vs. 25.7 +/- 6.0 degrees, P=0.0025, 140.3 +/- 16.1 vs. 127.3 +/- 13.2 degrees, P=0.0019, MPA, OPA, and GA, respectively), trending toward normalization. Airway diameter increased by 7.1 +/- 2.8mm. Anterior bite improved by 7.2 +/- 1.9mm. Complications arose in 2 subjects including device malfunction and wound infection.Curvilinear MDO results in dramatic cephalometric improvement in patients with severe microretrognathia and anterior open-bite. The procedure is associated with a high rate of complications, and long-term stability of movement has yet to be documented.