Effects of Pulsed Radiofrequency Duration in Patients With Chronic Lumbosacral Radicular Pain: A Randomized Double-Blind Study

Objectives We hypothesized that the duration of pulsed radiofrequency (PRF) application may affect the effectiveness of PRF in patients with chronic lumbosacral radicular pain (LRP). Materials and Methods In this prospective, double-blind, randomized study, 68 patients were randomly allocated to two groups: a 6-minute group, in which PRF was applied at 42 °C for 2 minutes followed by a 2-minute pause, repeated three times; and a 12-minute group, with a continuous application at 42 °C for 12 minutes. The total application time in each group was equal. After PRF, 2 to 3 mL of 1% lidocaine with 5 mg of dexamethasone was injected. The primary outcome was the intensity of leg pain measured using a numerical rating scale (NRS) three months after the procedure. The secondary outcomes were intensities of leg and back pain, the Oswestry Disability Index (ODI), the Medication Quantification Scale III (MQS), the Global Perceived Effect of Satisfaction (GPES), and the incidence of adverse events during follow-up. Primary and secondary outcomes were analyzed using a linear mixed-effect model in the modified intention-to-treat population. Results Each group comprised 34 patients. Three patients in each group did not receive the allocated intervention owing to alleviation of pain. The estimated NRS mean of leg pain at three months was 4.0 (95% CI, 3.2–4.9) and 4.5 (95% CI, 3.6–5.4) in the 6- and 12-minute groups, respectively, with no significant difference between groups (estimated mean difference, −0.5; 95% CI, −1.8 to 0.8; p = 0.436). Regarding the intensities of leg and back pain, ODI, MQS, and GPES, there was no significant difference between the two groups except for GPES at six months. No adverse events were observed in the groups. Conclusions Among patients with chronic LRP, a prolonged PRF application of 12 minutes, compared with 6 minutes, caused no significant difference in leg pain intensity. Clinical Trial Registration The Clinicaltrials.gov registration number under the Clinical Trial Registry of Korea for the study is KCT0003850; https://cris.nih.go.kr.