"Chemical radiculitis” is important in the generation of back pain. A primary focus of surgery is to remove mechanical compression on a nerve or the spinal cord. Back, neck, leg and arm pain, rather than being solely due to compression, may also be due to chemical inflammation. This may cause the nerve root to adhere to the canal, leading to nerve root traction with movement. The "hydraulic effect" of a fluid being placed directly within the adherent tissue causes the tissue to separate and allows the nerve to slide in it's channel more easily. For these reasons, epidural steroid injections often result in substantial pain relief, reduction of scar tissue, and return to functional activity. An advanced form of epidural, the transforaminal epidural or nerve root injection, provides the components of the "hydraulic effect" to separate the adherent tissue, proximity to the irritated nerve root and disk tear, and an anti-inflammatory delivered directly to the nerve, all helpful benefits resulting in pronounced and lasting effects in many patients.
Just something I thought was a cool part of an article and think may have possibly occured with my 3rd steroid injection, cant be sure of course but the first 2 did nothing then they targeted the annular tear that was believed to be causing some "chemical radiculitis" and the ESI worked great to stop knifing/stabbing pain. It was taken off a pain management site in austin, TX I saw months ago. So treating tears with ESI may be benefitial if you have one.