Revisiting the Sphenoid Sinus Anatomy in Trisomy 21: A CT Study

Objective: The aim of the study was to compare morphologic features of the sphenoid sinus (SS) in patients with trisomy 21 (T21) with a control group. Methods: This retrospective study contained computed tomography images of 50 T21s and 60 controls. Of 50 T21 patients aged 11.38±4.21 years, 22 were females and 28 were males. Of 60 controls aged 11.25±4.61 years, 30 were females and 30 were males. The volume (SSV), surface area (SSA), width (SSW), thickness (SST), and height (SSH) of SS were measured. The shape of SS was noted. Results: In T21s, median values for SSV, SSA, SSW, SST, and SSH were determined as 1.99 mm 3 , 1.52 mm 2 , 20.10 mm, 9.85 mm, and 13.60 mm, respectively. In controls, median values for SSV, SSA, SSW, SST, and SSH were determined as 9.55 mm 3 , 5.50 mm 2 , 30.44 mm, 19.67 mm, and 19.88 mm, respectively. T21s had statistically smaller SSV, SSA, SSW, SST, and SSH compared with controls ( P <0.001). Four types related to SS shape were observed in T21s (conchal: 42%, presellar: 30%, sellar: 24%, and postsellar: 4%) and controls (presellar: 33.3%, sellar: 31.7%, postsellar: 30%, and conchal: 5%). Thus, SS shape was affected by T21s ( P <0.001). Conclusions: Patients with T21 had statistically smaller SSV (about 79%), SSA (about 72%), SSW (about 34%), SST (about 50%), and SSH (about 32%) compared with controls. The most common pneumatization pattern in T21s was the conchal type.