Backpain, slipped disc and spondylolisthesis

Hi, I'm suffering, by now since quite some years, from backpain in the lumbar-sacral region, pain that ranges from mild to severe, depending on the day. Last october, after MR scans and Xrays, they found out that I have a slipped disc in L5-S1, and at the same point also a mild reverse spondylolisthesis (i.e., the upper spine has slipped backward with respect to the remaining lower part). However, I have no neurological defect, no pain in the legs, and no pain, though some stiffness, in the buttocks. Not a candidate for surgery, although the neurosurgeons suggested the possibility of inserting a spacer between the spinous processes. I'm dubious regarding such a spacer, because there's no long-time information, they're not sure it will help, and I fear it could makes a rupture more likely, in case of a climbing fall. By the way, the slipped disc had been seen also long time ago, but at the time they told me it was so slight that it was not the reason for my problems. I could not say how worse it is by now. Until one year ago I still was climbing from time to time, but it is almost a year by now that I don't touch rock. Climbing can make it much worse, the day after. I swam a lot, but it didn't go any better. Last weekend, for example, without any evident cause, I had extreme pain when trying to stand up straight, which developed in an hour and lasted three days. The first day even standing up was rather impossible, I had to spend most of the day in bed. And also in the bed the pain did not stop completely. I guess that was sciatica. I had a similar event also a couple of times before, but it was never so strong. Until today I tried non-steroidal painkillers, myorelaxing pills (katadolon S long), CO2 injections in the back muscles, physiotherapy, swimming, everything with short lasting or no result. Running used to make me feel better, but also that did not last, and now they told me to stop running as it is not good at all. I also had a series of four injections of Lidocain, Fortecorin and vitamin B (in the buttocks), and that seemed to had strong and lasting effects on the pain. However, a travel (train+flight) brought me back to my problems rather immediately. So, what am I going to do now? Will I ever climb again? Thanks a lot, and sorry for the long mail. Sandro Bosio