Background: A recent study showed that 50% of patients who suffered from refractory neuralgia of the infraorbital nerve obtained satisfactory efficacy after pulsed radiofrequency (PRF) treatment. A pilot study showed that increasing the output voltage of PRF significantly improved the efficacy for trigeminal neuralgia; however, whether increasing the output voltage of PRF can improve the treatment outcomes for neuralgia of the infraorbital nerve is unknown.
Objective: To evaluate the efficacy and safety of high voltage PRF treatment in comparison with standard voltage PRF for neuralgia of the infraorbital nerve.
Study design: Prospective, single-center, double-blinded, randomized, controlled trial.
Setting: Beijing Tiantan Hospital, Capital Medical University.
Methods: A total of 60 patients with refractory neuralgia of the infraorbital nerve were randomly divided into the high voltage PRF group and the standard voltage PRF group to treat their infraorbital nerves. Neither the patients, pain physicians, nor the follow-up evaluators knew the patient group assignments. The primary outcome measure was the one-year response rate. The secondary outcome measures included the time to take effect after PRF, the one-month, 3-month, and 6-month response rates, the relapse rate, and adverse reactions.
Results: The intent-to-treat analysis showed that the one-month, 3-month, 6-month, and one-year response rates were all 90% in the high voltage group, which were significantly higher than the rates in the standard voltage group (67% [P < 0.05], 67% [P < 0.05], 63% [P < 0.05], and 60% [P <0.01], respectively). Furthermore, 27% of the patients in the high-voltage group and 13% of the patients in the standard voltage group experienced minor transient (10 - 30 days) numbness in the innervation area after PRF; no other serious adverse reactions were observed in the 2 groups (P > 0.05).
Limitations: We did not investigate the dose-effect relationship between the output voltage and efficacy or the effect of a higher pulse dose on efficacy. This study was a single-center study, and multi-center, randomized, controlled studies are needed to obtain the highest level of empirical evidence. Additionally, the follow-up period lasted only one year in this study; thus, long-term efficacy needs to be further confirmed.
Conclusions: The results showed that high voltage PRF was effective and safe for patients with refractory neuralgia of the infraorbital nerve and could become a treatment option in patients who do not respond to conservative treatment.