Ross,
My wife had back surgery in 2004, L34 to 4 and 4 to 5 were fused. Prior to that she was virutally chair ridden. She worked really hard for months on the therapy to stretch ligaments, build strength, and regain fitness and went through a lot of discomfort doing it.
The good news - since then we have driven to Alaska and back 3 times and each time canoed 2 weeks on the Yukon River, sailed an aggregate of months on our HC37, bicycled a ton, canal boated in Belgium and England and are planning a bicycle trip in Germany later this year as well as a full year of sailing.
We feel so lucky to be alive in this day and age and place where we can get this kind of help. We hope it works out for you.