Recent reports have emerged suggesting that multiple sclerosis (MS) may be due 
to abnormal venous outflow from the central nervous system, termed chronic 
cerebrospinal venous insufficiency (CCSVI). These reports have generated strong 
interest and controversy over the prospect of a treatable cause of this chronic 
debilitating disease. This review aims to describe the proposed association 
between CCSVI and MS, summarize the current data, and discuss the role of 
endovascular therapy and the need for rigorous randomized clinical trials to 
evaluate this association and treatment.