Epidural steroid injections have been around for a long time. They are used to treat back and/or leg pain caused by disc problems or spinal stenosis (narrowing of the spinal canal). As you probably know from your experience, the surgeon uses fluoroscopy, a special type of X-ray that allows him or her to see the needle advancing toward and into the epidural space. This helps assure accuracy in getting the steroid where it can do the most good.
There are different places where the surgeon can insert the needle and inject the fluid. The type of problem you have determines the location of the injection. For example, spinal stenosis from thickening of the bone and ligaments along the back of the spine may respond better to a transforaminal approach. The needle is inserted from the side at an angle.
In such cases, an interlaminar technique might not work as well because the injected fluid can’t get past the hypertrophied tissue. And in order to reduce pain from pressure on the spinal cord, it’s best to have an injection that bathes the entire tissue with the steroid fluid. It may be necessary to inject the epidural space from both sides, not just from one side.
In the case of disc protrusion pressing or irritating a spinal nerve root, either approach (transforaminal or interlaminar) work fine. A one-sided translaminar approach works well if the disc is only protruding on one side of the spine. But if it’s more of a central protrusion, then either the interlaminar technique or simultaneous transforaminal approaches (both sides at the same time) may be needed.
You may want to talk with your surgeon more about this procedure. Which technique was used in the first two procedures? What are the likely reasons it didn’t have any apparent effect? Why does the surgeon think a third injection will be any more effective than the first two injections? The answers to these questions may help you in making the final decision about this third injection.