Changes in width of lower face after unilateral mandibular distraction osteogenesis

Distraction osteogenesis (DO) has been popular to improve hypoplastic mandible in patients with hemifacial microsomia in craniofacial surgery. However, changes in width of the lower face after DO still lack in literatures. The aim of this pilot study was to evaluate cephalometric changes in width of the lower face at different time points after DO and to give an insight into the influence on facial contour. A total of 10 patients (8 males and 2 females) with hemifacial microsomia received DO of the mandibular body measured by posteroanterior cephalograms. Five landmarks (crista galli, latero-orbitale, gonion of the unaffected side, incisor point superior of the unaffected maxilla, incisor point inferior of the unaffected side of the mandible) were chosen for cephalometric analysis. Six distances from the soft tissue contour perpendicularly to the vertical reference line (through crista galli) were calculated through the incisor point superior of the unaffected maxilla, gonion of the unaffected side, incisor point inferior of the unaffected side of the mandible. Measurements were taken preoperatively and postoperatively on the day distraction started (time 1), at the end of distraction (time 2), and at the end of the consolidation period (time 3). Calculations for statistical significance were done for all patients. Mean differences between 3 periods were measured by repeated-measures analysis with significance determined at the 0.05 level of confidence. The results suggested that the values of 6 distances at times 2 and 3 had no significant differences when compared with the values at time 1 (P>0.05). In conclusion, DO of the unilateral mandibular body in patients with hemifacial microsomia should not be beneficial to improve the width of the lower face at a short-term follow-up.