Is surgery recommended for severe spinal stenosis?

Last Resort. Yes, surgery is recommended after you fail conservative non-surgical treatments -- including nsaids, pt, epidural injections. If you continue to have persisting symptoms, then surgery could offer some great symptomatic relief of your extremity symptoms. Consult a spine surgeon. Also surgery if you start experiencing progressive neurological deficit, or changes in your bowel or bladder function.
Yes. If weakness or pain progresses, it can often be minimized by surgery.