Morphometry of the mandible in prepubertal craniofacial microsomia patients following an inverted L osteotomy

Abstract

The aim of this study was to undertake finite element modeling of craniofacial microsomia (CFM) patients who exhibited a unilateral mandibular deformity that was surgically corrected by an inverted L osteotomy and autogenous bone graft. Preoperative, 1-year, and 3-year postoperative anteroposterior cephalographs of 14 consecutive children (mean age, about 9 years) with CFM were employed. All cephalographs were scanned, and 8 homologous mandibular landmarks were digitized in triplicate (digitization error < 1%; P > 0.05). Average mandibular geometries, scaled to an equivalent size, were generated using Procrustes superimposition and subjected to analysis of variance. Results showed that while the mean pre- and early postoperative mandibular configurations marginally failed to differ statistically, finite element modeling of the affected mandibular ramus showed a positive allometry (a lengthening by about 10% to 12%) and marked anisotropy, presumably reflecting the surgical procedure carried out in that region. For the preoperative and late postoperative means, the configurations were statistically different (P < 0.002), showing a lengthening of the ramus (about 14%) while the unoperated side had a high degree of isotropy. The early and late postoperative configurations were also statistically different (P < 0.002). The operated ramus showed an increase in length (about 15%), but the corpus showed a decrease in size (about 10%) and marked anisotropy that reflected remodeling associated with the surgical procedure. Although mandibular morphology is improved in CFM patients who are surgically treated by an inverted L osteotomy, some relapse is evident due to deficient growth, localized in the mandibular ramus and body of the affected side.