However, MS and Lyme are not correlated and must be diagnosed and treated as two diseases.
MS is not a disease per say. MS is a compilation of symptoms (scattered CNS lesions affecting various body functions).
The causes of those symptoms can be Lyme, can be CCSVI, can be mercury poisoning, we don't know for sure yet.
Can CCSVI weaken the body so it would be more susceptible to bacteria? Absolutely. Borrelia Burgdorfery did not just emerge from thin air. The bacteria was in existence way before we, the humans, were.
Our susceptibility to that bacteria however has increased.
Hence, I believe that looking at the possible connection with MS in general and CCSVI in particular should be encouraged.
Further to that, what of the possibility that Lyme (or one of its co-morbidities) causes CCSVI? Babesiosis has a predilection for the endothelial cells, for one. Biofilms, L-form bacteria, encysting bacteria, are all possible culprits. The problem is, what research has been done is labeled as quackery (sound familiar?), and there are billions of tourist dollars at stake for Lyme-endemic areas (which, coincidentally, have high rates of "MS"). I don't know of many couch potatoes with "MS" - they all seem to be formerly active outdoors people.
Nobody knows what causes "MS", and Lyme is largely ignored and denied. I am going after chronic bacteria as a possible cause of my own tribulations, and Lyme is my principal suspect - it has been since the beginning. I'll let you know how it goes.
Edit - being properly tested for Lyme disease is no easy feat, either. Doctors who treat for Lyme with long-term abx are also subject to having their licenses pulled (in British Columbia, at least). Further to that, the BC CDC has been proven to be under-reporting Lyme by as much as 30X. Over 600 people per year are infected in BC, while the BC CDC reports ~20. These numbers are from Doctor surveys, and only about 30% of doctors respond, so the numbers could be much higher. I can't find any statistics on how many cases of "MS" are diagnosed each year, so I am not sure of any statistical co-relation.