Correlative factors of sigmoid sinus diverticulum formation in individuals without pulsatile tinnitus based on CT angiography

Objective: To analyze the correlative factors of sigmoid sinus diverticulum(SSD) formation in individuals without pulsatile tinnitus based on computed tomography angiography (CTA). Methods: A hospital-based 1ratio2 matched case-control study was performed on 42 cases with unilateral SSD and 84 controls for age, gender, and side-matched in Beijing Friendship Hospital affiliated to the Capital Medical University from January 2018 to December 2018.The signs including sigmoid sinus wall dehiscence, venous outflow dominance, transverse sinus stenosis, high jugular bulb, large emissary veins, degree of mastoid pneumatization (grade -) and empty sella, were detected and analyzed. Results: In SSD group and control group, there were statistically significant differences in the incidence of the sigmoid sinus wall dehiscence (66.7%(28/42) vs 19.0%(16/84)), ipsilateral transverse sinus stenosis on the dominant side of venous outflow (26.2%(11/42) vs 4.8%(4/84)), and empty sellae (19.0%(8/42) vs 7.1%(6/84))(all P<0.05).The degree of mastoid pneumatization was worse in SSD group (P<0.05). After stepwise logistic regression analysis,the sigmoid sinus wall dehiscence (P<0.01,OR=6.794,95%CI 2.530-18.245), ipsilateral transverse sinus stenosis on the dominant side (P=0.001, OR=13.293, 95%CI 2.841-62.194), and degree of mastoid pneumatization (P<0.01, OR=0.289, 95%CI 0.156-0.536) were found independently correlated with SSD. Conclusion: Sigmoid sinus wall dehiscence, ipsilateral transverse sinus stenosis on the dominant side of venous outflow and mastoid pneumatization may be some of the independent correlative factors of SSD.