Hi
A prolapsed disc is a severe condition that needs careful and specialist handling by someone who really understands what is going on. A full prolapse of the disc, rather than a bulge of the disc, implies that the nucleous pulposus has ruptured through the anulus fibrosus and is pressing on one of the nerve roots as the nerve leaves the spine. This is what will cause the pain in the Sciatic Nerve and the distribution of this referred pain will be an indication of the level within the spine at which the prolapse has ocurred. The nerve is not trapped along it's whole length, the problem is local to the back and the pain is referred along the course of the nerve. As we age the nucleus polposus is less jelly-like and a full prolapse is less likely. This does not preclude referred pain from being present, it just means that the cause is likely to be more due to degenerative disc disease or arthritis.
If there is pressure on the nerve as it exits the spinal column the nerve will become inflamed. The body will attempt to heal this and there is a likelyhood that scar tissue will form (internally known as adhesions). If this adheres to surrounding structures this can then aggravate the problem by tugging on the nerve root and adding to the pain. You mention that your wife has had several nerve root blocks and epidural injections. My advise would be not to have more. If they have not helped to date then further ones are unlikly to help. Also, each time a needle is stuck in, or near, to a nerve minor trauma will occur. This is unavoidable. This can further aggravate the nerve and surrounding tissue and may even lead to more internal scarring.
I am a physiotherapist and a Bowen Therapist and would advise that you see a Physiotherapist, make sure they are MCSP (member of the Chartered Society of Physiotherapy) and registerd with the HPC (Health Professions Council). Physios know their anatomy and understand what is happening and have several techniques that will help. This is a common problem and Physiotherapists deal with it on a daily basis.
As a Bowen Therapist I know the value of this technique and have used it extensively in my practice. It can help enormously to relax and re-align the body. If you can find someone who is both Physio and Bowen trained than that would be great. If not then I would recommend Physiotherapy and ask your practitioner if she minds if you also visit a Bowen Therapist.
I do hope this helps. The problem should not be insurmountable.
Gill