Herniated l5-s1 herniation post l5-s1 laminectomy w/ fusion, why can't i be surgically treated when all has failed ?

Surgery possible: If you have had a fusion and some of the disc remains and reherniated to cause your current symptoms and you have imaging that correlates, surgery is possible to relieve the pressure on the nerve. The other question a spine surgeon would try to answer is whether or not your fusion healed. An evaluation by a spine surgeon will be helpful.

Vague question: Assuming you mean why _further_ surgery is not advised (the laminectomy & fusion certainly are surgeries!) there may be many factors including general health. However, i would suspect that scar tissue formation around nerves in the area of prior surgery may be so intertwined with the nerves, matted down, that one might easily damage the nerves trying to take away the scar tissue.