Effectiveness and Safety of High-Voltage Pulsed
Radiofrequency to Treat Patients with Primary
Trigeminal Neuralgia: A Multicenter, Randomized,
Double-Blind, Controlled Study Protocol
Authors: Fang Luo 
Published: October 2019

Background: Trigeminal neuralgia (TN) is a neurological syndrome characterized by paroxysmal,
lightning-like, severe pain in the facial area innervated by the trigeminal nerve. Patients who do not
respond well to drug treatment can undergo a nerve block, a traditional conservative treatment.
Pulsed radiofrequency (PRF) is a nondestructive pain intervention technique. However, its treatment
effectiveness for TN has rarely been reported and remains controversial among scholars. A recent
single-center preliminary clinical study showed that high-voltage PRF was significantly effective in
the treatment of TN. However, whether high-voltage PRF is a viable pain treatment option for TN
patients who are unresponsive to drug treatment must still be confirmed with standardized clinical
studies by utilizing conservative nerve block treatment as a control.
Objective: To compare theeffectiveness and safety of high-voltage PRF and nerve block for
primary TN patients who have failed to respond topharmacological treatment and who are seeking
a better non-surgical treatment option.
Study Design: Prospective, multicenter, randomized, double-blind, controlled clinical trial.
Setting: Three interventional pain management centers in Beijing, China.
Methods: The study will include 134 consecutive patients with primary TN who have failed to
respond to drug treatment. The patients will be randomly assigned to 2 groups, the nerve block
group and the PRF group. The nerve block group will be slowly injected with 1.4 mL of a mixture
of dexamethasone and lidocaine after 360 s of sham PRF treatment, and 0.5 mL of normal saline
will be administered before the needle is withdrawn. The PRF group will undergo 360 s of 42°C
PRF treatment at the highest output voltage that the patients can tolerate, after which the patients
will be injected with the same concentration and volume of lidocaine and normal saline that the
nerve block group receives. The Barrow Neurological Institute (BNI) pain intensity scale will be used
to assess the degree of pain relief before and after the treatment.
Results: The effectiveness and safety of high-voltage PRF and nerve block to treat TN will be
analyzed to determine significant differences in pain relief and functional improvement. The primary
efficacy outcome measure is the response rate at one-year post-operation (BNI I-III/total number of
cases*100%). Secondary efficacy outcome measures include the response rate at postoperative
day 1, week 1, week 2, month 1, month 3, month 6 and year 2, the patient satisfaction score
(PSS) at various time points, the dosage of antiepileptic drugs (milligrams per day), and information
regarding patients with a BNI score of IV or V who switch to other therapies.
Limitations: The effects of the waveform, treatment duration, frequency and other parameters
of PRF deserve further investigation.
Conclusions: This is the first multicenter, double-blind, randomized controlled study to compare
the efficacy and safety of PRF and nerve block to treat TN patients who have failed to respond to
drug treatment. Moreover, the value of PRF in TN treatment may need to be clinically clarified with
evidence-based medical support and other advanced studies.
Key words: Trigeminal neuralgia, effectiveness, safety, pulsed radiofrequency