Morphometric analyses of the mandible in prepubertal craniofacial microsomia patients treated with an inverted-L osteotomy.

Abstract

To analyze changes in mandibular form associated with an inverted-L osteotomy and autogenous bone graft, preoperative, early postoperative (EPO), and late postoperative (LPO) lateral cephalographs of 14 children (mean age approximately 9 years) with unilateral craniofacial microsomia (CFM) were scanned and nine mandibular landmarks digitized. Average mandibular geometries, scaled to an equivalent size, were generated using Procrustes superimposition. Cephalometry, Euclidean distance matrix analysis (EDMA), and thin-plate spline (TPS) analyses were carried out on mean mandibular configurations. Cephalometric results showed increases in oblique mandibular length (approximately 9% on average, P < 0.05) and increased ramus height (P < 0.05). Similarly, using EDMA there were also significant differences (P < 0.05) between the mean preoperative, EPO, and LPO configurations. The most demonstrable EPO change in the mandibular configuration using EDMA was increased oblique length (approximately 11%). This improvement depended on ramus oblique lengths increasing by approximately 26%, ramus height increasing by approximately 25%, and mandibular body length increasing by approximately 5%. For TPS analysis, affine and nonaffine changes contributed to the total spline. In all three comparisons the affine transformation showed an antero-inferior rotation of the mandibular configuration. For nonaffine changes the EPO configuration indicated a supero-inferior stretch of the mandibular configuration. The nonaffine LPO changes maintained the supero-inferior stretch of the mandibular configuration. It is concluded that improvements in the lateral facial profile of CFM patients can be achieved using an inverted-L osteotomy, with little relapse approximately 2 years postoperatively.