How often cortisone injections are given varies based on the reason for the injection. This is determined on a case-by-case basis by the health care practitioner. If a single cortisone injection is curative, then further injections are unnecessary. Sometimes, a series of injections might be necessary; for example, cortisone injections for a trigger finger may be given every three weeks, to a maximum of three times in one affected finger. In other instances, such as knee osteoarthritis, a second cortisone injection may be given approximately three months after the first injection, but the injections are not generally continued on a regular basis.
Epidural steroid injections are commonly prescribed for patients with a disc injury or spinal arthritis causing nerve irritation, and generally consist of local anesthetic (numbing medication such as lidocaine) and cortisone (a steroid that reduces inflammation and pain). Lidocaine is often injected initially so patients experience minimal, if any, pain during the procedure. The injection may be performed by placing the needle posteriorly between the spine bones (Translaminar or interlaminar) and injecting the medicine into the space around the spinal nerves. A transforaminal ESI means the injection is placed slightly to one side of the spine, and the medicine is injected near the ruptured disc and inflamed spinal nerve. A caudal ESI is performed by placing the needle near the tailbone, and injecting the medicine into the region of the sacral nerves and lower lumbar spinal nerves. Epidural steroid injections, as well as most spinal injections, are performed using a special x-ray guidance system called fluoroscopy. This allows the doctor to immediately see an x-ray image on a television screen and inject the medicine precisely into the right spot. The procedure time is often less than 10-15 minutes.
Epidural injections are often used to treat radicular pain, also called sciatica , which is pain that radiates from the site of a pinched nerve in the low back to the area of the body aligned with that nerve, such as the back of the leg or into the foot. Inflammatory chemicals (. substance P, PLA2, arachidonic acid, TNF-α, IL-1, and prostaglandin E2) and immunologic mediators can generate pain and are associated with common back problems such as lumbar disc herniation or facet joint arthritis . These conditions, as well as many others, provoke inflammation that in turn can cause significant nerve root irritation and swelling.