Bone to Soft Tissue Changes Following Box Osteotomy and Facial Bipartition for Surgical Correction of Hypertelorism: A Three-dimensional Analysis

PURPOSE: Box osteotomy (BO) or facial bipartition (FB) are used for the surgical correction of hypertelorism. Both procedures have been shown to successfully reduce interdacryon distance and the overlying soft tissue. There is a paucity in the literature assessing the degree to which bony resection translates into soft tissue movement. This study analyzes the bony and soft tissue changes achieved with BO and FB. METHODS: A retrospective review was conducted evaluating patients who underwent BO or FB at our institution from 2005-2023. Demographics, medical history, and perioperative data were recorded. Correction of the interdacryon distance and intercanthal distance were measured on pre- and post-operative computed tomography scans. Three-dimensional craniometric data was derived using Mimics software. Paired and Independent t-tests were utilized. The ratio of bone-to-soft tissue change was computed by calculating the change in the intercanthal distance for every 1mm change in the interdacryon distance. RESULTS: Twenty-nine patients were included, of which 20 underwent FB and 9 BO. There was a significant improvement in the interdacryon distance (28.8mm to 22.1mm; p<0.001) and intercanthal distance (43.5mm to 38.2mm; p<0.001) for FB patients. Similarly, there was a significant improvement in the interdacryon distance (37.1mm to 25.8mm; p<0.001) and intercanthal distance (47.7mm to 39.9mm; p<0.001) for BO patients. The percent change in the interdacryon distance was 22.4% (FB) and 30.4% (BO; p=0.017), whereas the percent change in the intercanthal distance was 11.0% (FB) and 14.7% (BO, p=0.193). The ratio of bone-to-soft tissue change was 1-to-0.8 across both cohorts (BO: 1-to-0.9, FB: 1-to-0.7; p=0.502). CONCLUSIONS: Box osteotomy and facial bipartition effectively correct hypertelorism, demonstrating significant bone and soft tissue changes. Our findings revealed that 1mm of interorbital bone resection correlated with 0.8mm change in the overlying soft tissue for both hypertelorism-correcting procedures.