I've asked questions before about my discectomy for nerve damage, i know i shouldn't smoke but doctors put emphasis on it with back problems why?

Smokers have poorer: Surgical outcomes with any spine surgery compared to a nonsmoker. Smoking accelerates the natural rate of disc degeneration 4 times faster and smokers herniate discs at rate twice as often as nonsmokers. Smokers have increased risks of post op infection & wound healing problems. The exact mechanisms are not fully understood but the implications are!

Fusion: If your surgery involved a fusion, smoking will almost certainly prevent proper healing.

Smoking: Smoking in general is not good for your overall health and also for your spine health. It also significantly decreases the chances of a successful fusion and therefore the chances of optimal pain relief.