The Effectiveness of Medial Branch Blocks and Radiofrequency Neurotomy in Managing Chronic Thoracic Pain: A Systematic Review and Meta-Analysis.

Background: Extensive research into potential sources of thoracic pain with or without referred pain into the chest wall has demonstrated that thoracic facet joints can be a potential source of pain confirmed by precise, diagnostic blocks.The objective of this systematic review and meta-analysis is to evaluate the effectiveness of medial branch blocks and radiofrequency neurotomy as a therapeutic thoracic facet joint intervention.

Methods: Systematic review and meta-analysis of randomized controlled trials (RCTs) and observational studies of medial branch blocks and the radiofrequency neurotomy in managing thoracic pain utilizing the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) checklist was performed. A comprehensive literature search of multiple databases of RCTs and observational studies of medial branch blocks and radiofrequency neurotomy in managing chronic thoracic pain were identified from 1996 to December 2022 with inclusion of manual searches of the bibliography of known review articles and multiple databases. Methodologic quality and risk of bias assessment was also conducted. Evidence was synthesized utilizing principles of quality assessment and best evidence synthesis, with conventional and single meta-analysis. The primary outcome measure of success was 3 months of pain reduction for medial branch blocks and 6 months for radiofrequency thermoneurolysis for a single treatment. Short-term success was defined as up to 6 months and long-term was more than 6 months.

Results: This literature search yielded 11 studies meeting the inclusion criteria, of which 3 were RCTs and 8 were observational studies. Of the 3 RCTs, 2 of them assessed medial branch blocks and one trial assessed radiofrequency for thoracic pain. The evidence for managing thoracic pain with qualitative analysis and single-arm meta-analysis and GRADE system of appraisal, with the inclusion of 2 RCTs and 3 observational studies for medial branch blocks was Level II. For radiofrequency neurotomy, with the inclusion of one RCT of 20 patients in the treatment group and 5 observational studies, the evidence was Level III in managing thoracic pain.

Limitations: There was a paucity of literature with RCTs and real-world pragmatic controlled trials. Even observational studies had small sample sizes providing inadequate clinically applicable results. In addition, there was heterogeneity of the available studies in terms of their inclusion and exclusion criteria, defining their endpoints and the effectiveness of the procedures.

Conclusion: This systematic review and meta-analysis show Level II evidence of medial branch blocks and Level III evidence for radiofrequency neurotomy on a long-term basis in managing chronic thoracic pain.

Key Words: Chronic spinal pain, thoracic facet or zygapophysial joint pain, facet joint nerve blocks, medial branch blocks, controlled comparative local anesthetic blocks, diagnostic accuracy, radiofrequency neurotomy.