Craniofacial changes in unilateral microtia: II. An X-ray study.

Roentgenocephalometry was used for studies into the extent and character of craniofacial changes in 45 adult males with unilateral (right-sided) microtia. Out of the whole complex of changes associated with this malformation the mandibular ramus showed the most marked involvement and represented the main cause of the accompanying deviations and asymmetries. On the average, the affected half of the face was compressed toward the level of the external auditory meatus both from above and below, but there was a marked variability in individual patients examined. No signs of asymmetry were disclosed in one third of the patients while severe asymmetry was present in one fifth of the patients. Facial hemihypoplasia exerted no substantial influence on the facial profile (when no retrusion of the lower jaw was present) on the sagittal maxillomandibular relations or on the occlusion of incisors, while in transverse direction a laterosuperior deviation of the mandible towards the affected side was clearly visible. A branchiogenic malformation affected the neighboring structures, the cranial base (a more marked curving), frontonasal segment (septum and premaxillar deviation), and the neurocranium (posterior rotation of the cranial vault). The inner ear structures (semicircular canals) were affected only rarely (in 4% of patients). These findings complemented the results obtained in the first part of our study and confirmed the complex character of this inborn anomaly.