When your MRI shows Tarlov cysts, and any kind of treatment does not work. I had my MRI done first time in 2010, back pain, lower abdominal and groin pain, left leg (not below my knee), could not lay on my back without pain so bad, like something is tearing inside. I went two different Dr. I had epidural inj., steroid inj. so many different inj., physical therapy(that made it worse), finally second Dr. suggested to see Dr. F. in Dallas. That was 2 years later. I had surgery 18 months ago with 5 cysts in my sacrum, and doing very well. Wishing you best.