Comparable effectiveness of caudal vs. trans-foraminal epidural steroid injections

Retrospective case-control study.

To compare the effectiveness between caudal and trans-foraminal epidural steroid injections for the treatment of primary lumbar radiculopathy.

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.

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.

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).

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.