For patients with lumbosacral disk herniation (LDH) being considered for epidural steroid injection (ESI) to treat back and radicular pain, transforaminal ESI (TFESI) may be superior to caudal ESI (CESI) in terms of clinical outcomes, according to findings published in The Spine Journal, although results from this systematic review and meta-analysis did not reach statistical significance.
Although CESI is effective and more commonly used for the treatment of LDH-related pain, the use of TFESI may offer better outcomes because it allows the delivery of steroid medications directly to the target area.
For this analysis, the investigators searched MEDLINE, EMBASE, KoreaMed, and Cochrane review databases for studies published through July 2017 that examined the efficacy of TFESI vs CESI for the treatment of LDH-related leg pain and low back pain. From 6711 articles reviewed, 6 (4 randomized controlled trials [RCT] and 2 non-RCT) were selected for qualitative analysis; 4 (3 RCT and 1 non-RCT) of these studies were also included in a quantitative analysis to evaluate statistical significance and effect size.
Outcomes of interest included pain — as assessed with the visual analog scale or numeric rating scale — and functional limitation, which was measured using the Oswestry disability index. The Grading of Recommendations Assessment, Development and Evaluation method was used to determine level and quality of evidence.
In the qualitative synthesis, 4 of the 6 chosen studies indicated that TFESI was superior to CESI, 1 study found CESI to be superior to TFESI, and 1 study found the 2 techniques comparable. When the techniques were compared by quantitative meta-analysis, investigators found TFESI to be clinically superior to CESI at short- and long-term follow-up (1 month and 6 months, respectively), although these results were not found to be statistically significant.
The mean difference in pain scores over 3 studies was 1.43 point (95% CI, -0.37 to 3.24; P =.12) at 1 month and 0.14 point (95% CI, -0.54 to 0.81; P =.69) at 6 months, both in favor of TFESI. The mean difference in functional improvement, as assessed with the Oswestry disability index, was 0.25 (95% CI, -10.33 to 10.83; P =.96) at 1 month and 2.30 (95% CI, -13.82 to 18.41, P =.78) at 6 months, both favoring TFESI over CESI. Heterogeneity was high for all measures, ranging from I2 = 88% to I2 = 99%.
Imprecision and inconsistency across the studies examined resulted in a low level of evidence. The investigators suggested that increasing the amount of injectate beyond that traditionally used might allow CESI to achieve results comparable with those seen with TFESI.
Study limitations included high heterogeneity, which lowered the statistical power of the meta-analysis, and weak level of evidence.
“TFESI is preferred to CESI due to its target specificity, although discomfort during the needle approach occurs more frequently in TFESI,” noted the authors when considering clinical implications of their review. “As a result, TFESI can be weakly recommended over CESI, even though controversy about the advantage of TFESI might still remain.”