Modelling of the dilated sagittal sinuses found in multiple sclerosis suggests increased wall stiffness may be a contributing factor

Abstract

The cross-sectional area of the superior sagittal sinus (SSS) is larger in multiple sclerosis than normal and correlates with disease severity and progression. The sinus could be enlarged due to a decrease in the pressure difference between the lumen and the subarachnoid space, an increase in wall thickness or increased wall stiffness. The cross-sectional area of the SSS and straight sinus (ST) were measured in 103 patients with multiple sclerosis and compared to 50 controls. The cross-sectional area of the SSS and ST were increased by 20% and 13% compared to the controls (p = 0.005 and 0.02 respectively). The deflection of the wall of the sinus was estimated. The change in pressure gradient, wall thickness or elastic modulus between groups was calculated by modelling the walls as simply supported beams. To account for these findings, the modelling suggests either a 70% reduction in transmural venous pressure or a 2.4 fold increase in SSS wall stiffness plus an 11% increase in wall thickness or a combination of changes. An increase in sinus pressure, although the most straight forward possibility to account for the change in sinus size may exist in only a minority of patients. An increase in sinus wall stiffness and thickness may need further investigation.

Chronic Fatigue Syndrome and Multiple Sclerosis have Reduced Craniospinal Compliance and Dilated Pressurized Bridging Cortical Veins: A Hypothesis Illustrated with Two Case Studies

“…Previously we have measured these veins using an identical technique in several studies. In 50 controls of average age 44.9 ± 10.9 years, the cross-sectional area of the SSS 3cm above the torcular from post contrast 3DT1 images averaged 44.9± 10.9 mm 2 and the mid portion of the straight sinus averaged 15.7± 5.4 mm 2 [18]. The bridging vein between the deep venous system of the brain and the straight sinus is the vein of Galen.…”

“…Given the similarities found between CFS and MS, one would be tempted to suggest that CFS is essentially MS without the autoimmune mediated white matter destruction. Recently, we have found the cross-sectional area of the superior sagittal sinus (SSS) to be larger in MS than in controls [18]. This enlargement correlates with disease severity and progression [18].…”

“…Recently, we have found the cross-sectional area of the superior sagittal sinus (SSS) to be larger in MS than in controls [18]. This enlargement correlates with disease severity and progression [18]. Modelling indicated the sinuses in MS could be enlarged due to a decrease in the pressure difference between the lumen and the subarachnoid space, an increase in wall thickness or increased wall stiffness [18].…”

“…This enlargement correlates with disease severity and progression [18]. Modelling indicated the sinuses in MS could be enlarged due to a decrease in the pressure difference between the lumen and the subarachnoid space, an increase in wall thickness or increased wall stiffness [18]. However, only the last two possibilities were feasible [18].…”

“…Modelling indicated the sinuses in MS could be enlarged due to a decrease in the pressure difference between the lumen and the subarachnoid space, an increase in wall thickness or increased wall stiffness [18]. However, only the last two possibilities were feasible [18]. An increase in sinus wall stiffness or thickness would render the craniospinal compartment less compliant than normal.…”