I'm not a doctor, but I would like to share my personal experiences with back pain and kiting.
My back operation goes back (bad pun) about 15 years now. I had pieces of something sucked out from between my vertebrea in the lower part of my back after shattering something from lifting rocks....went for one that was way toooo big. Before the op, my right leg went off and I was in a drug induced state from medicine for 6 months. Spent most times in bed. After the op I could walk again immediately and felt like a full person. However, I had to do physio therapy and there were to be no more rotations or compressions.......very depressing. No more sports like b-ball, base ball, golf, skiing...then end of the world.
But one of my Dr. friends in the US said that spinal injuries will heal, but take a very long time to do so. And it did heal

! Slowly slowly I began to do all sports again but I always have to be very careful using an almost medatative approach.
My back does not like bumpy up and down motion at all. Vertical vibrations under pressure cause the material in my back to shift again. Learning to kite I took some serious risks to my fragile back, but survived by learning to use my legs and just hang from the kite... all to time streaching the spine. Going up wind in not choppy waters is very good for my back

Now that I am learning to jump I have had some very bad landings (landing flat on the board

) that have cuased the material in my back to shift again. But, now for the best part

....when I actaully land softly, the jumping session streatches my back so well that I'm good again.
Wow, kiting is actaully good for my one personal back

.
Boy, do I need some wind....back needs some thearapy