There are a lot of articles now on this new meta-analysis (which looked at all the imaging studies we've already discussed to get an overall consensus). It's interesting because the spin goes both ways. Dr. Fox stated in one article that he was concerned that CCSVI advocates would take this latest study as validation of CCSVI. The results are favorable to CCSVI, yet there is much more research to be done.
But before getting distracted by any opinion pieces being published about this research, first here is the original abstract:http://www.cmaj.ca/content/early/2011/10/03/cmaj.111074
Association between chronic cerebrospinal venous insufficiency and multiple sclerosis: a meta-analysis
Jodie M. Burton,
+ Author Affiliations
From the Keenan Research Centre (Laupacis, Lillie, Straus, Perrier, Thorpe, Spears), Li Ka Shing Knowledge Institute of St. Michael's Hospital, Toronto, Ont.; the Faculty of Medicine (Laupacis, Dueck, Straus, Aviv, Spears), University of Toronto, Toronto, Ont.; the Schulich Heart Centre (Dueck), Sunnybrook Health Sciences Centre, Toronto, Ont.; the Office of Continuing Education and Professional Development (Perrier), Faculty of Medicine, University of Toronto, Toronto, Ont.; the Department of Clinical Neurosciences (Burton), Hotchkiss Brain Institute, University of Calgary, Calgary, Alta.; the Department of Medical Imaging (Aviv), Sunnybrook Health Sciences Centre, Toronto, Ont.; the Dalla Lana School of Public Health (Thorpe), University of Toronto, Toronto, Ont.; and the Faculty of Medicine (Feasby), University of Calgary, Calgary. Alta.
Background: It has been proposed by Zamboni and colleagues that multiple sclerosis is caused by chronic cerebrospinal venous insufficiency, a term used to describe ultrasound-detectable abnormalities in the anatomy and flow of intra- and extracerebral veins. We conducted a meta-analysis of studies that reported the frequency of chronic cerebro spinal venous insufficiency among patients with and those without multiple sclerosis.
Methods: We searched MEDLINE and EMBASE as well as bibliographies of relevant articles for eligible studies. We included studies if they used ultrasound to diagnose chronic cerebrospinal venous insufficiency and compared the frequency of the venous abnormalities among patients with and those without multiple sclerosis.
Results: We identified eight eligible studies: all included healthy controls, and four of them also included a control group of patients with neurologic diseases other than multiple sclerosis. Chronic cerebrospinal venous insufficiency was more frequent among patients with multiple sclerosis than among the healthy controls (odds ratio [OR] 13.5, 95% confidence interval [CI] 2.6–71.4), but there was extensive unexplained heterogeneity among the studies. The association remained significant in the most conservative sensitivity analysis (OR 3.7, 95% CI 1.2–11.0), in which we re moved the initial study by Zamboni and colleagues and added a study that did not find chronic cerebrospinal venous insufficiency in any patient. Although chronic cerebrospinal venous insufficiency was also more frequent among patients with multiple sclerosis than among controls with other neurologic diseases (OR 32.5, 95% CI 0.6–1775.7), the association was not statistically significant, the 95% CI was wide, and the OR was less extreme after removal of the study by Zamboni and colleagues (OR 3.5, 95% 0.8–15.8).
Interpretation: Our findings showed a positive association between chronic cerebrospinal venous insufficiency and multiple sclerosis. However, poor reporting of the success of blinding and marked heterogeneity among the studies included in our review precluded definitive conclusions.