On the Origin of Bitemporal Hollowing

Introduction: Long-term results after cranioplasty for trigonocephaly often show bitemporal hollowing and a residual hypotelorism. Both findings fuel the perception that the growth of the periorbital region and the forehead as a whole continues to be restricted, even after correction. The aim of this study was to evaluate the growth process of the periorbital region after correction for trigonocephaly in the long term. Materials and Methods: From 1972 to 2004, 184 patients underwent a cranioplasty for the correction of nonsyndromatic trigonocephaly. Cephalometric analysis was performed in 33 of these patients who had their radiographs taken on the same day as the photograph, at least 1 year postoperative and before the age of 6 years. Cephalic landmarks were used to analyze the growth of the forehead. Because of the lack of standardized cephalograms, growth ratios were used instead of absolute measurements. For visual analysis, normal anteroposterior photographs were used, which were taken on the same day as the radiograph. Two observers evaluated the anteroposterior photographs for the presence and level of temporal hollowing. A score of 0 (normal), 1 (moderate deformity), or 2 (severe deformity) was assigned to each of the photographs. Results: A significant relation was found between a severe deformation seen at postoperative photographic evaluation and a lower growth ratio. The preoperative photo score was not of predicting value for the postoperative growth ratio and therefore, indirectly, for the postoperative photo score. The mean preoperative photo score dropped 5% after surgery. The age at operation had no influence on this postoperative photo score. The experience of the surgeon, however, was a significant contributing factor. Conclusions: Temporal hollowing seems to be of bony origin and can be explained by skeletal growth inhibition in the affected area. When present immediately after operation, they seem to persist through the years, which makes surgical skill another factor of importance.