Effect of different volumes on pain relief in patient receiving fluoroscopic guided interlaminar lumbar epidural steroid injection

Background: Epidural steroids injections (ESI) are frequently used to treat lumbar radicular pain. Although different volume have been used for interlaminar ESI in adults, there is no controlled trial comparing the effect of different volumes on pain relief for the same dose of steroid. Objective: To compare the effect of increase in volume of epidural drug on pain relief in lumbar ESI. Study design: Randomized double blind trial Settings: Pain OR of a tertiary care centre Methods: Sixty patients were randomly allocated to 1 of 3 groups: Group A (4 mL), Group B (6 mL), and Group C (8 mL). Pain was evaluated using visual analog scale (VAS) and improvement in disability using modified Oswestry Disability Questionnaire scores (MODQS) at 2, 4, 8, 12, and 24 weeks. Patients having less than 50% pain relief from baseline received an additional epidural injection of the same volume with a maximum of 3 injections at least 15 days apart. The primary objective of the study was incidence of patients attaining more than 50% pain relief at 6 months. Secondary outcome included MODQS and pattern of spread of iodinated contrast on fluoroscopy. Results: At the end of 6 months, there was no significant difference in the effective pain relief between the 3 groups (Group A-16/22 (72.7%), Group B-15/20 (75%), Group C-13/18 (72.2%); P = 0.98, chi-square test). All groups demonstrated a significant reduction in mean VAS scores. There was no significant intergroup difference in VAS sores and MODQS at all the time intervals. The pattern of contrast spread did not differ between the 3 groups. Limitation: Not a placebo controlled trial Conclusions: An increase in volume of the injectate from 4 mL to 8 mL did not increase the efficacy of interlaminar ESI.