Abnormalities of the TMJ and the musculature in the oculo-auriculo-vertebral spectrum (OAV). A CT study.

The abnormalities covered by the generic term "oculo-auriculovertebral spectrum" (OAV) form an exceptional heterogeneous dysmorphic complex characterized by unilateral malformations of miscellaneous craniofacial structures. The aim of the present study was to analyze morphometrically the developmental deficits concerning the temporomandibular joints, the mandibular rami and the mastication muscles by comparing the affected with the non-affected side. The volume, maximum horizontal diameter, and trabecular bone density of the head of the mandible, as well as the ramus height were acquired from CT data of 16 patients suffering from this syndrome. The volume and maximal cross-sectional area of the masseter muscles and the pterygoid muscles were defined by quantifying CT data of nine patients. The skeletal parameters were evaluated with VoXim software. The comparison of the mandibular structures on the affected and on the non-affected side was based on the Wilcoxon signed rank test. The results recorded on the affected side showed that the TMJ volume was reduced by a mean factor of 7.98, and the spongiodensity of the head of the mandible by a mean factor of 1.33, while the mean reduction in ramus height was 14.89 mm. The muscle volumes on the affected side had also undergone a mean reduction of 9.10 cm(3). The CT-based data analysis proved to be an excellent tool for quantitative three-dimensional evaluation of both the skeletal and the muscular parameters.