I am sorry to hear your problem. Though I am not a spina bifida victim, I had severe back pain 17 years ago. After many diagnostics, it was found that my L4-L5 was prolapsed to a minimal degree. I was put under many painkillers, acupuncture, physiotherapy, but no cure. Finally, one fine day I met a Homeopathy Doctor who gave treatment for my back pain. I continued for 2 years. Then step by step the pain got reduced.
Now am suffering from Multiple sclerosis for the past 3 years. I had 3 strokes sequentially. Besides the primary problem, I have been again started with severe dorsal and lumbar pain. It is unexplainable. Daily I am suffering from such a terrible chronic pain. Still under painkillers, muscle relaxants, physiotherapy, but no remedy at all.
In your case, if the cause of pain is found, it can be corrected. Oral NSAIDs, intravenous medications, Occupational therapy, natural treatments, Anti-stress therapy, you may try out. Speak to your Doctor about pain management since the surgery is not possible in your case. I pray God to alleviate your pain as early as possible. Take care dear.