Comparison of Clinical Efficacy of Transforaminal and Interlaminar Epidural Steroid Injection in Radicular Pain due to Cervical Diseases: A Systematic Review and Meta-analysis

Background: Cervical epidural steroid injection (ESI) has been used to alleviate axial or radicular pain incurred from various cervical pathologies, including herniated intervertebral disc (HIVD) and spinal stenosis (SS). However, the superiority of the transforaminal ESI (TFESI) method over the interlaminar ESI (ILESI) in terms of clinical effectiveness for the radicular pain is still controversial.

Objectives: This study has compared TFESI and ILESI in terms of clinical effectiveness, such as pain control and functional improvement, as well as the incidence of adverse events in patients with radicular pain secondary to cervical HIVD or SS.

Study design: A systematic review and meta-analysis.

Setting: Primary clinic and tertiary referral center.

Methods: A literature search was performed using Medline (PubMed), Embase, Cochrane Review, and KoreaMed databases from the studies published until March 2022. After reviewing titles, abstracts, and full texts of 371 studies during the initial database search, 6 studies were included in a qualitative and quantitative synthesis. Data, including pain score, functional score, and adverse events were extracted from 6 studies and were analyzed using a random-effects model to obtain effect size and its statistical significance. Quality assessment and evidence level were established in accordance with the Grading of Recommendations Assessment, Development and Evaluation methodology.

Results: Among 6 studies, including 4 randomized controlled trials (RCTs), only 1 RCT showed that TFESI achieved a significant lower Numeric Rating Scale (NRS-11) at 1 month than ILESI, but no advantage in the NRS-11 at 3 months and the Neck Disability Index at 1 month and 3 months, respectively. Another RCT indicated that ILESI achieved significantly more neck NRS-11 reduction at 1 month and 3 months than TFESI. The other 4 studies revealed no significant difference between the 2 groups. A meta-analysis showed no significance in clinical outcomes, except that ultrasound-guided TFESI featured less intravascular leakage of contrast than ILESI. The level of evidence was low because of inconsistency and imprecision.

Limitations: The feasible clinical heterogeneity from the relatively small number of patients included as well as differences in methodology across the studies.

Conclusions: Comprehensive reviews of selected articles revealed TFESI could not be recommended over ILESI for the sake of a preferential cervical radiculopathy control due to the weak evidential strength.