Long-term cranial shape outcomes in metopic synostosis: A 12-year follow-up study using 3D photography.

Abstract

Restoring a normal head shape is a key objective in surgery for metopic synostosis. Few studies have examined long-term results due to challenges in data collection and reliance on ionizing CT scans. Recent advances in 3D photography offer a promising, non-invasive method to accurately assess cranial shape and track outcomes over time. We conducted a retrospective longitudinal cohort study using 3D analysis to assess cranial shape outcomes after surgery for metopic synostosis over a 12-year follow-up period. Using a craniofacial growth curve from a dataset of healthy controls, we objectively compared individual cases to their age- and sex-matched average. Using these features, we defined a data-driven metopic severity score (MSS) to accurately estimate the severity of the deformity at different timepoints. Immediate postoperative images indicated good correction of the head shape, reflected in a reduction in MSS. At 8 and 12 years, cranial shapes showed a significant recession of the forehead and an increase in vault height, with a high preoperative severity score correlating to more severe recession. However, MSS did not significantly change compared to postoperative levels, indicating that this does not represent a relapse to the preoperative phenotype. We identified a consistent long-term head shape outcome for surgically corrected metopic synostosis, marked by a retrusion of the forehead and tendency toward a turricephalic vault rather than a relapse into trigonocephaly. These findings underscore the value of 3D shape analysis as a tool for assessing long-term cranial outcomes and informing surgical planning.