1. 2022;25;E1327-E1337Radiofrequency Therapies for Trigeminal Neuralgia: A Systematic Review and Updated Meta-analysis
   Systematic Review
   Danyan Liu, PhD, Lihua Peng, PhD, and Xiaoyu Zhang, MSc.

BACKGROUND: Conventional radiofrequency (CRF), pulsed radiofrequency (PRF), and pulsed com-bined conventional radiofrequency (PCRF) are widely used in the clinical treatment of trigeminal neuralgia (TN), collective evidence comparing the efficacy and safety of these radiofrequency therapies is still controversial.

OBJECTIVES: To provide additional evidence for the efficacy and safety of different radiofrequency therapies in the management of TN to update this section of the systematic review of Wu et al 2019.

STUDY DESIGN: A secondary systematic review and meta-analysis was conducted.

METHODS: Systematic database research about double-blind, randomized controlled trials (RCTs) was conducted based on PubMed, Embase, and Web of Science. Literature on TN in adults under different radiofrequency therapies was collected to evaluate pain scores, excellent pain relief, and occurrence of adverse effects after corresponding therapies.

RESULTS: A total of 11 studies, including 570 patients, were involved in our systematic review. Two studies from the same research team and one study with a completely different pain assessment tool were excluded from the meta-analysis. Ultimately, 8 studies, including 412 samples, were included in the quantitative synthesis. In secondary analyses, as with the report of Wu and colleagues, we also observed a safer outcome in PRF than CRF when regarding the occurrence of adverse effects. Nevertheless, unlike the last meta-analysis, despite no statistical difference in pain scores between CRF and PRF one week after surgery, a positive impact was observed in the CRF group one month and 3 months after surgery. A meta-analysis of 6 studies comparing PCRF and CRF was conducted and revealed no evidence to prove excellent pain relief of PCRF and CRF groups at 6 months, one year, and 2 years after surgery. However, a positive influence in reducing pain scores was observed in the PCRF group. Subgroup analysis further exhibited that PCRF positively affected TN when the temperature was lower than 70°C.

LIMITATIONS: (1) A small overall sample of included trials; (2) the diversity of tools used for pain assessment across trials, such as VAS, BNI, and NRS, limits the evaluation of outcomes; (3) a high risk exists for most studies in the meta-analysis for at least one domain, which may affect the reliability of results; (4) the short follow-up period of a few studies in the meta-analysis while the long-term efficacy of different radiofrequency treatments may require longer follow-up data to enhance the accuracy of the assessment.

CONCLUSIONS: PCRF provides better long-term efficacy and fewer adverse effects for treating TN. Yet, it is hard to draw definitive conclusions about excellent pain relief comparisons due to the moderate quality of evidence, high heterogeneity, and scarcity of available data.

KEY WORDS: Radiofrequency therapy, trigeminal neuralgia, systematic review, meta-analysis