Efficacy of interlaminar vs transforaminal epidural steroid injection for the treatment of chronic unilateral radicular pain: prospective, randomized study.

UNLABELLED: OBJECTIVE, DESIGN AND SETTINGS: The purpose of this randomized, prospective study is to compare the efficacy of two different routes in administering epidural steroid injections interlaminar (IL) vs transforaminal (TF) in patients with unilateral radicular pain. PATIENTS: We randomly enrolled and followed 64 patients with chronic radiculopathy. RESULTS: Significant improvements were maintained throughout 6 months (24 weeks) of follow-up (P<0.001, respectively). The average visual analog scale (VAS) pain scores at 24 weeks improved to 4.0 ± 2.2 cm in the IL group and 3.8 ± 2.1 cm in the TF group (P=0.717). Baseline functional capacity was comparable for the IL and the TF group (52% vs 53%) when assessed using Oswestry (P=0.647). At 6 months, both groups improved, 39% for the IL group and 38% for the TF group, suggesting change from severe to moderate disability scoring range. There were 24 out of the 32 (75%) patients in the IL group at 24 weeks who improved more than 2 cm on the VAS scale and 17 patients (53%) had >50% of the pain relief. In the TF group, there were 27 out of the 32 (84%) patients with >2 cm improvement on VAS pain scale, and 20 of 32 (63%) with >50% improvement at 24 weeks. Functional capacity changes were similar, 16 out of the 32 patients (50%) improved 10 points or more on the Oswestry scale in the IL group and 21 out of the 32 in the TF group (66%). CONCLUSIONS: Using either route of epidural injections to deliver steroids for unilateral chronic radiculopathy secondary to herniated intervertebral disc provided significant improvements in patients function and pain relief. However, we could not find a statistically significant difference between two indicated groups either in functional improvement or in reduction in pain, although half-dose of steroids delivered via TF route provided somewhat better long-term pain relief and functional capacity improvements.