Radiculopathy occurs when something irritates a spinal nerve—say a “slipped disc” causing a pinched nerve. This is also called sciatica . There are resident stem and other cells in the local tissues everywhere in our body. Many live around blood vessels. These are obviously also present in the disc and nerves in the epidural space and they usually play an important role in suppressing inflammation and repairing damage. We know, based on a copious in vitro (lab) data, that the high-dose steroids used in epidural injections can kill these cells. So the progression of the series of epidural steroid injections looks a little something like this:
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.