Pulsed radiofrequency treatment of the lumbar dorsal root ganglion in patients with chronic lumbar radicular pain: a randomized, placebo-controlled pilot study

Abstract

BackgroundNo proof of efficacy, in the form of a randomized controlled trial (RCT), exists to support pulsed radiofrequency (PRF) treatment of the dorsal root ganglion (DRG) for chronic lumbar radicular (CLR) pain. We determined the feasibility of a larger trial (primary objective), and also explored the efficacy of PRF in decreasing pain on a visual analog scale (VAS) and improving the Oswestry Disability Index.MethodsThis was a single-center, placebo-controlled, triple-blinded RCT. Patients were randomized to a placebo group (needle placement) or a treatment group (PRF at 42°C for 120 seconds to the DRG). Patients were followed up for 3 months post procedure. Outcomes with regard to pain, Oswestry Disability Index score, and side effects were analyzed on an intention-to-treat basis.ResultsOver 15 months, 350 potential patients were identified and 56 were assessed for eligibility. Fifteen of them did not meet the selection criteria. Of the 41 eligible patients, 32 (78%) were recruited. One patient opted out before intervention. Three patients were lost to follow-up at 3 months. Mean VAS differences were not significantly different at 4 weeks (−0.36, 95% confidence interval [CI], −2.29, 1.57) or at 3 months (−0.76, 95% CI, −3.14, 1.61). The difference in mean Oswestry Disability Index score was also not significantly different at 4 weeks (−2%, 95% CI, −14%, 10%) or 3 months (−7%, 95% CI, −21%, 6%). There were no major side effects. Six of 16 patients in the PRF group and three of 15 in the placebo group showed a >50% decrease in VAS score.ConclusionThe recruitment rate was partially successful. At 3 months, the relative success of PRF-DRG was small. A large-scale trial to establish efficacy is not practically feasible considering the small effect size, which would necessitate recruitment of a challengingly large number of participants over a number of years. Until clear parameters for application of PRF are established, clinicians will need to use their individual judgment regarding its clinical applicability, given the present evidence.

Transforaminal Epidural Injection of Local Anesthetic and Dorsal Root Ganglion Pulsed Radiofrequency Treatment in Lumbar Radicular Pain: A Randomized, Triple‐Blind, Active‐Control Trial

“…The study group received PRF for 120 seconds, while the control group received low‐intensity sensory stimulation. No statistically significant difference in mean VAS or ODI scores was found between the 2 groups at 4 weeks and 3 months . However, the recruitment process was incomplete, with 23 patients recruited over 2.5 years.…”

“…Only a few randomized controlled trials are known that compared PRF as a treatment with other modalities in chronic LRP . In one randomized controlled trial, 70% of patients with LRP receiving PRF reported a significant reduction in pain (≥2 points and/or ≥30% decrease in VAS score) at 2 months, whereas a significant reduction in pain was found in 82% of patients receiving a combination of PRF and CRF at the same time interval.…”

“…Only a few randomized controlled trials are known that compared PRF as a treatment with other modalities in chronic LRP. 27,[31][32][33]52 In one randomized controlled trial, 27 70% of patients with LRP receiving PRF reported a significant reduction in pain (≥2 points and/ or ≥30% decrease in VAS score) at 2 months, whereas a significant reduction in pain was found in 82% of patients receiving a combination of PRF and CRF at the same time interval. A higher rate of successful treatment results (≥50% or a 4-point reduction in NRS score with a decrease in GPE) was demonstrated in 48.4% and 38.7% of patients with chronic LRP who received PRF of the DRG with transforaminal epidural steroid injection (TFESI) compared to 19.4% and 9.7% of patients receiving TFESI alone at 2 and 3 months, respectively.…”

“…No statistically significant difference in mean VAS or ODI scores was found between the 2 groups at 4 weeks and 3 months. 52 However, the recruitment process was incomplete, with 23 patients recruited over 2.5 years. So, the study was prematurely abandoned.…”

Interventional Modalities for Chronic Pain Management

“…Hence, should be used after careful patient selection 77 . However pulsed radiofrequency may be give satisfactory pain relief 78 . According to studies, intervertebral disc is responsible for about 39% of low backache 35 .…”