What is the relationship between chronic cerebrospinal venous insufficiency and multiple sclerosis?

Although most of the research on multiple sclerosis was focused on its autoimmune aspects, researchers were also considering the roles of other factors, including vascular background of the disease. The idea that multiple sclerosis might be caused by stenoses of the veins draining the brain and spinal cord (the so-called chronic cerebrospinal venous insufficiency), is currently hotly debated by scientific community. Despite conflicting reports, chronic cerebrospinal venous insufficiency seems to be a real clinical phenomenon. However, it remains uncertain how it should be defined and which tests should be used for its detection. Probably this vascular abnormality should be primarily diagnosed using catheter venography, while non-invasive tests, especially Doppler sonography, seem to be of limited diagnostic accuracy. Causative role of these venous lesions in the pathogenesis of multiple sclerosis remains to be established. However, it is unlikely that they are directly triggering multiple sclerosis. Rather, they represent a permissive pathology. Probably chronic cerebrospinal venous insufficiency is linked to multiple sclerosis in such a way that it favors disease development in relatively low-predisposed subjects. Besides, it is suggested that a potential link between chronic cerebrospinal venous insufficiency and other neurodegenerative diseases should be examined.