Metopic synostosis: quantitative assessment of presenting deformity and surgical results based on CT scans

Our study applied a method of using 14 clinically relevant measurements of CT scan images to document skeletal dysmorphology in patients with metopic synostosis to determine the effectiveness of their surgical procedure after a minimum of 1 year. Ten consecutive patients with metopic synostosis who underwent a standard surgical procedure were reviewed. Preoperative and postoperative (> 1 year) CT scans were compared with those of age-matched controls. Percentages of normal were then compared for significant differences. Preoperative cranial vault measurements revealed a narrowed anterior intercoronal distance at 92 percent of normal. Orbital measurements showed a narrowed anteromedial wall interorbital distance at 79 percent of normal, a narrowed lateral orbital wall distance at 94 percent, and an elevated medial orbital wall protrusion beyond the plane of the lateral orbital walls at 115 percent. After surgery, the intercoronal distance was significantly corrected to 101 percent, the anteromedial wall interorbital distance was improved but remained undercorrected at 90 percent, and the medial wall protrusion was significantly decreased to 98 percent of normal. Quantitative measurements of CT scan images confirmed clinically observed physical findings in unoperated trigonocephaly to be orbital hypotelorism, retruded lateral orbital rims, and a narrowed bitemporal width. The surgical technique corrected the lateral orbital wall aspects of the deformity as well as the narrowed anterior cranial vault width and improved the orbital hypotelorism.