They do not refer to specific problems. Disc degeneration in the spine is very common and may or may not cause symptoms. Transthoracic endoscopic surgery can be used for any one of a number of problems. A thoracic disc herniation, or in scoliosis when anterior disc removal is necessary to make the spine looser, so that correction of the curve can be more easily accomplished. It is especially useful in children with large curves.
Spinal surgery is effective if the surgery is done technically well for the right diagnosis.
Secondly, I fear that 25 to 30 years after a patient has titanium implanted into their spine, as their bone loses density, they may have an increased chance of fracturing around a non-pliable metallic device. I have made the decision for many of my patients that using a bone graft instead of titanium, which would be incorporated would, in fact, preclude this complication. You seem to be advocating surgery for more problems. If the nerve is truly being compressed, and is causing nerve compression symptoms, and has not spontaneously resolved with conservative therapy, then surgery in many instances can help. What I see most commonly is that those physicians who do not advocate surgery under most every condition will commonly lose that patient to follow up and will not benefit from an understanding of how surgery can improve a patient's symptoms.