Abstract QS3: Cranial Fossa Volume And Morphology Development In Apert Syndrome

Abstract

Background: Apert patients develop normal or enlarged intracranial volume overall with growth. This study aims to trace the segmental anterior, middle and posterior cranial fossae volume, and structural morphology in these patients, in order to help discern a more focused and individualized surgical treatment plan for Apert syndrome patients. Methods: Eighty-two preoperative CT scans (Apert, n=32; control, n=50) were included in this study, and divided into 5 age related subgroups. CT scans were measured using Mimics and 3-matics software. Results: The volume of middle cranial fossa is increased and is the earliest change noted. It is increased by 45%(p=0.023) compared to controls before 6 months of age, and remains increased into adulthood (161%, p=0.016) with gradual increasing severity. The anterior and posterior cranial fossae volumes also increased, by 35%(p=0.032) and 39%(p=0.007) respectively. Increased depth of cranial fossae contributes most to the increase in cranial fossae volumes of Apert syndrome, with correlation coefficient 0.799, 0.908 and 0.888 for anterior, middle and posterior cranial fossa, respectively. The intracranial volume is increased 12%(p=0.098) across the entire test age range (0-26 years old), but only had statistical significance during the age range of 6-18 years (22%, p=0.001). Conclusions: The malformation of middle cranial fossa is an early, perhaps the initial pivotal cranial morphologic change in Apert syndrome. Increased depth of cranial fossae is an inherent character of the maldevelopment. Normalization of cranial volume and circumference overall may not achieve a normal skull structure, as it does not correct regional craniocerebral disproportion.