Dorsum Sellae Morphology in Chiari Malformation Type I: A CT-Based Study

Objective: To evaluate the morphology of the dorsum sellae (DS) on computed tomography (CT) in patients with Chiari malformation type I (C1M) and to compare the findings with those of controls. Methods: This retrospective case-control study included 120 individuals who underwent cranial CT, comprising 60 patients with C1M and 60 control subjects. Results: Several morphometric features of the DS differed significantly between the C1M and control groups. In the C1M group, the distance between DS and foramen magnum was shorter (43.15 vs. 46.00 mm, p < 0.001), whereas the distance between DS and anterior clinoid process (17.20 vs. 15.10 mm, p < 0.001) and the angle between the crista galli, DS, and foramen magnum (133.44° vs. 125.30°, p < 0.001) were greater. In addition, the transverse width of the DS was smaller, whereas midline height, bilateral lateral heights, and anteroposterior thickness were greater in the C1M group (all p < 0.001). DS pneumatization was also more frequent in patients with C1M (23.3% vs. 5.0%, p = 0.007). Conclusions: Distinct DS morphometric characteristics and an increased frequency of DS pneumatization were observed in patients with C1M. These findings may contribute to a better understanding of skull base anatomy in C1M.