Study Design: Retrospective case-control study.
Objective: To compare the effectiveness between caudal and trans-foraminal epidural steroid injections for the treatment of primary lumbar radiculopathy.
Summary of Background Data: Spinal injections with steroids play an important role in non-operative care of lumbar radiculopathy. The trans-foraminal epidural steroid injection (TESI) theoretically has a higher success rate based on targeted delivery to the symptomatic nerve root. To our knowledge, these results have not been compared with other techniques of epidural steroid injection.
Methods: 93 patients diagnosed with primary lumbar radiculopathy of L4, L5, or SI were recruited for this study: 39 received caudal epidural steroid injections (ESI) and 54 received trans-foraminal epidural steroid injections (TESI). Outcomes scores included the SF-36, Oswestry disability index (ODI) and pain visual analogue scale (VAS), and were recorded at baseline, post-treatment (<6 months), long-term (>1 year). The average follow-up was 2 years, and 16 patients were lost to follow-up. The endpoint “surgical intervention” was a patient-driven decision, and considered failure of treatment. Intent-to-treat analysis, and comparisons included t-test, Chi-square, and Wilcoxon rank-sum test.
Results: Baseline demographics and outcomes scores were comparable for both treatment groups (ESI vs. TESI): (SF-36 PCS (32.3 ± 7.5 vs. 29.5 ± 8.9 respectively; p = 0.173), MCS (41.2 ± 12.7 vs. 41.1 ± 10.9, respectively; p = 0.971), and VAS (7.4 ±2.1 vs. 7.9 ± 1.2, respectively; p = 0.228)). Surgery was indicated for failure of treatment at a similar rate for both groups (41.0% vs. 44.4%, p=0.743). Symptom improvement was comparable between both treatment groups (ESI vs. TESI): SF-36 PCS improved to 42.0±11.8 and 37.7±12.3, respectively; p=0.49; ODI improved from 50.0±21.2 to 15.6±17.9and from 62.1±17.9 to 26.1±20.3, respectively (p=0.407).
Conclusions: The effectiveness of TESI is comparable to that of ESI (approximately 60%) for the treatment of primary lumbar radiculopathy. The increased complexity of TESI is not justified for primary cases, and may have a more specific role in recurrent disease or for diagnostic purposes.