(735): Epidural steroid injection efficacy is a function of the contrast dispersion pattern

Abstract

Epidural steroid injections (ESI) may provide relief of radicular pain associated with lumbar disc herniations. Inflammation from a disc herniation occurs primarily in the ventral epidural space at the site of the disc injury. Epidural steroids should therefore, be deposited at the level of the disc lesion in the ventral epidural space. Epidural needle placement can be accomplished by one of three methods: caudal (C), translaminar (TL) or transforaminal (TF). The purpose of this study is to analyze epidurogram contrast dispersion patterns in the epidural space using the three routes of epidural needle placement. After patient informed consent and IRB approval, 60 patients with L5-S1 disc herniations were randomly assigned to have epidural steroid injections by one of three methods for epidural needle placement; caudal (n=20), translaminar (n=20) and transforaminal (n=20). Each procedure was performed with fluoroscopy using a 22 gauge Tuohoy needle. Each patient received 3 ml of iohexol 300 with 5 ml preservative saline with 40 mg of triamincolone in Groups TL and TF and 20 ml preservative saline with 40 mg steroid in Group C after proper needle placement was ascertained by epidurogram observation. Fluoroscopy was repeated at 30 min post injection. Statistical analysis was done using the Fisher Exact test with p <0.05 to reject the null hypothesis. Observed epidural contrast dispersion patterns were; V=ventral, AP =anterior-posterior and P= posterior; Caudal (n=20), V=0/20 (0%), AP=11/20(55%), P=9/20, (45%); Translaminar (n=20) V=2/20 (10%), AP= 8/20 (40%), P=10/20 (50%) and Transforaminal (n=20), V=18/20 (90%), AP, 2/20 (10%), P=0/20 (20%). Pain relief two weeks following the ESI was as follows: C, 9/20 (45%), TL, 10/20 (50%), TF, 15/20 (75%). Transforaminal ESI resulted in significantly (p<0.05) greater pain relief with a single epidural steroid injection which is attributed to a higher incidence of steroid placement within the ventral epidural space.