<s>[INST] Hey Docs. I ve been fighting a bad back for 20 years and it appears I m going to have to get a decompression operation (L4-L5). I ve put this off for a long as I can, but getting around this pain is getting really old. My question is; do I have reasonable chance to get some long term relief? I m in reasonably good health but I do smoke a pack a day. Thanks for your consideration. [/INST] Hi, From your information it seems you have a condition where there is a nerve compression for a prolapsed disc or a stenosis (narrowing of the canal caused by either the disc or extra bone formations or even a shift in the vertebral position). All these causes a bad back but essentially leads to pains shooting down the limb and disturbances in sensation. So to answer your question, if the MRI does show a nerve affection or an unstable vertebral bone, and it correlates with your symptoms and signs, then there is a good chance that you will get pain relief.However, this is along standing condition and your back muscles will be weak and contracted which means intensive physiotherapy will be required.Furthermore, you are a moderately heavy smoker and this will in no way help pain relief or a quick recovery so think about quitting! </s>