An intradiscal injection can be performed for either a diagnostic or therapeutic procedure. As a diagnostic procedure it is an injection of local anesthetic that temporarily removes the pain from a patient. If the injection is administered and the patient still feels pain then the doctor will try an adjacent level.
As a therapeutic treatment a longer lasting steroid is injected into the disc to reduce inflammation or swelling that is cause pain. It takes 2-3 days for the steroid in the injection to have effect, with best effects being felt between a week or two after the injection. Some patients will benefit from months of pain relief while others will only feel temporary effects of the steroid. There is no way to know how long your relief will be until you have undergone the procedure.