There are three common methods for delivering into the epidural space: the interlaminar, caudal, and transforaminal approaches. All three approaches entail placing a thin needle into position using fluoroscopic (x-ray) guidance. Prior to the injection, contrast dye is used to confirm that the medication is traveling into the desired area. Often, local anesthetic is added along with the steroid to provide temporary pain relief.
An interlaminar epidural injection, often referred to simply as an ‘epidural injection’, involves placing the needle into the back of the epidural space and delivering over a wider area. Similarly, the caudal approach uses the sacral hiatus (a small boney opening just above the tailbone) to allow for needle placement into the very bottom of the epidural space. With both approaches, medication will often spread over several spinal segments and cover both sides of the spinal canal. With a transforaminal epidural injection, often referred to as a ‘nerve block’, the needle is placed alongside the nerve as it exits the spine and medication is placed into the ‘nerve sleeve’. The medication then travels up the sleeve and into the epidural space from the side. This allows for a more concentrated delivery into one affected area (usually one segment and one side). Transforaminal epidural injection can also be modified slightly to allow for more specific coverage of a single nerve and can provide diagnostic benefit, in addition to improved pain and function.
All three procedures are performed on an outpatient basis, and you can usually return to your pre-injection level of activities the following day. Some patients request mild sedation for the procedure, but many patients undergo the injection using only local anesthetic at the skin.