Simultaneous maxillo-mandibular distraction in early adolescence as a single treatment modality for durable correction of type II unilateral hemifacial microsomia: Follow-up till completion of growth.

Abstract

Timing of surgical intervention in hemifacial microsomia (HFM) is controversial. Although mandibular osteodistraction in childhood for HFM is popular, recent data for single-stage distraction in growing HFM patients demonstrated long-term relapse. Literature suggests that adolescents in the late mixed dentition age or permanent dentition age (11-16-year-old) had more stable outcomes post-distraction than younger children. We present favorable experience using single-treatment simultaneous maxillo-mandibular distraction in early adolescent Pruzansky-Kaban type II HFM patients. This was a retrospective longitudinal study of seven consecutive type IIa/b HFM growing patients (12-16-year-old) treated with simultaneous maxillo-mandibular distraction. Oral commissure cant was photographically measured preoperatively and at 6 months and annually ranging 3-7 years post-distraction. Ramus height and chin deviation were measured from radiographs done preoperatively and at distractor-removal, 1 year, 2 years, and 4 years post-distraction. Average age at osteodistraction and at latest follow-up was 13.7 and 18.6 years, respectively. Improvement was significant (p<0.05) and sustained for mean oral commissure cant (5.1°-0.41°), mean ramus height ratio (0.59-0.86), and average chin deviation (15.9mm-1.2mm). Two subjects had mandibular branch palsy and one had mild pin-tract infection - all resolved. All were satisfied with their facial appearance. We have demonstrated good lasting outcomes at completion of growth with single-stage simultaneous maxillo-mandibular distraction for type II HFM adolescents in the late mixed-dentition or older age, and advocate this as an alternative to osteodistraction or orthognathic surgery upon skeletal maturity.