S8A-10 SESSION 8A: METOPIC SYNOSTOSIS COMPARISON OF HEAD SHAPE OUTCOMES IN METOPIC SYNOSTOSIS: LIMITED STRIP CRANIECTOMY VERSUS FRONTO-ORBITAL RECONSTRUCTION

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Introduction: True metopic craniosynostosis (MCS), with its severely trigonocephalic head shape, is often treated with either limited incision strip craniectomy (LISC) followed by helmet orthotic treatment, or open fronto-orbital reconstructive techniques (FOR). There is controversy regarding resultant shape outcomes among craniofacial surgeons. Those adverse to LISC claim normal head shape is never attained, while proponents believe there is gradual correction to an equivalent outcome. This has become contentious, with anecdotal claims frequently the basis of the opposing arguments. No whole head quantitative 3D outcome studies, with normal controls, have been done to support these arguments. This study aims to address these gaps. Methods: 3D images of 31 patients with MCS, were analyzed retrospectively with a 1:1 cohort of age-matched normals. Head shape analyses were performed at: 1) pre-op; 2) 1 month post-op; 3) 10–14 months post-op; 4) 25–36 months post-op. 3D composite heads of MCS patients at each time point were calculated and compared to normal controls and to each other. 2D standardized cross sections of the forehead were also compared and statistically analyzed. Results: In the LISC group, improvement spread laterally across the forehead over time. Hypotelorism improved as well. By 1 month post-op the flatness of the forehead ridge extended to the medial canthus, by 10–14 months it extended to the orbitale superius, and by 25–36 months, it approached the lateral canthus. In the FOR group, after 1 month the forehead contour was nearly spherical. The height of the cranium increased at 1 year post-op. By 25–36 months, there was some widening of the interorbital distance, but no further change in forehead contour. Comparing the LISC vs. FOR groups using contour color maps, which describe protrusion or retrusion as compared to normal, the contours of the groups were similar, albeit not the same size due to age differences. In the 2D analysis, the total differences between LISC and FOR groups also decreased to a point of similarity over time. Conclusion: Both LISC and FOR techniques achieved a normal head shape, reducing the magnitude of shape differences between each intervention and normal cohorts. The pace of head shape improvement was different between the two techniques, consistent with the intuitive expectation that FOR would normalize more quickly, achieving its best approximation to normal by 1 month post-op. However, LISC achieved a similar equivalence to the normal cohort by 10–14 months post-op. This study supports the assertion that both techniques accomplish the goal of normalizing head shape.