Steroid injection has some possible problems. It's still less risky than surgery. Some doctors advise trying up to three injections before going to surgery. Some patients get better after only one injection.
Some studies show injection or surgery works best when 25 percent or more of the disc is pressing into the spinal canal. Less than 25 percent usually gets better with nonoperative treatment. Anti-inflammatory drugs, physical therapy, and exercise should be tried first.
If the injection doesn't work, you can always have the discectomy. Research shows delaying a discectomy doesn't affect the results. Likewise, having a steroid injection first doesn't seem to affect results later after a discectomy.