Evaluation of fluoroscopic caudal epidural steroid injections.

To the Editor: Two articles, one by Botwin (1) and the other by Manchikanti (2), in the January 2004 edition of Pain Physician helped confirm that patterns of epidural injections exist, depending on the site of injection among other variables. Botwin concluded that ventral spread, considered the target site, only occurs 36% of the time with interlaminar injections, and bilateral spread only 16% of the time. Manchikanti demonstrated that caudal injections may reach lumbar levels but do not always fill the suspected pain generator target. I would like to add some observations. We pain physicians typically rely on injected corticosteroid to produce the benefits of epidural injections. Corticosteroids are not highly diffusible ionic agents such as the local anesthetics that often spread far beyond the injections site. Rather, we inject particulate sustained-release corticosteroids which may remain close to the site of injection. My own unpublished cadaver study done for a local surgical club highlights this graphically, and was presented at the ASIPP annual meeting in September 2002. I injected a scoliotic cadaver spine with pigmented suspensions by the interlaminar and transforaminal routes,