The efficacy of combining pulsed radiofrequency with low-temperature continuous radiofrequency for the treatment of primary trigeminal neuralgia: a randomized controlled trial.

Objective: Pulsed radiofrequency (PRF) combined with low-temperature continuous radiofrequency (CRF) might be a novel technique for relieving trigeminal neuralgia (TN). This study aimed to evaluate the efficacy and safety of high-voltage PRF combined with low-temperature CRF in primary TN.

Methods: This randomized controlled trial was performed between December 2, 2020, and October 26, 2022. Eligible patients with TN were randomly assigned at a 1:1 ratio to receive either PRF with a voltage of 70 V at 42°C for 600 seconds followed by CRF at 60°C for 270 seconds (PRF+CRF group) or PRF with a voltage of 70 V at 42°C for 600 seconds (PRF group). The primary outcome was the response rate to treatment after 12 months. The secondary outcomes were the proportion of responders at 1 day, 1 week, 2 weeks, 1 month, 2 months, 3 months, and 6 months following the procedure and the 11-point numeric rating scale (NRS) scores at 1 day, 1 week, 2 weeks, 1 month, 2 months, 3 months, 6 months, and 12 months following the procedure. Adverse events associated with surgery were also observed.

Results: A total of 169 patients with TN were screened, and 146 patients were randomized. The groups were well balanced across baseline characteristics. The percentage of responders at 12 months after surgery was significantly greater in the PRF+CRF group compared with the PRF group (83.6% [61/73] vs 67.1% [49/73], risk ratio 1.2 [95% CI 1.0-1.5], absolute difference 16.5%; p = 0.021). There was a higher proportion of responders after 1 day, 1 week, 2 weeks, 1 month, 2 months, 3 months, and 6 months (ratio difference 16.5%, 35.6%, 16.4%, 12.3%, 12.3%, 12.3%, and 15.1%, respectively; all p < 0.05). Moreover, lower NRS scores were observed in the PRF+CRF group at 1 day, 1 week, 2 weeks, 1 month, 2 months, 3 months, 6 months, and 12 months following the procedure (all p < 0.05). Postoperative facial numbness scores were higher in the PRF+CRF group at 1 day, 1 week, 2 weeks, 1 month, and 2 months (all p < 0.05). Overall, 5.5% of patients in the PRF+CRF group and no patients in the PRF group reported masseter muscle weakening. No other complications, such as anesthesia dolorosa and corneal anesthesia, were observed in either group.

Conclusions: High-voltage PRF combined with low-temperature (60°C) CRF could provide a significant improvement compared with high-voltage PRF alone. Clinical trial registration no.: NCT04174443 (ClinicalTrials.gov).