Effectiveness of Pulsed Radiofrequency with Multifunctional Epidural Electrode in Chronic Lumbosacral Radicular Pain with Neuropathic Features

Background: Lumbosacral radicular pain is a common clinical finding with a statistical prevalenceranging from 9.9% to 25% in the general population.Objective: To investigate the effectiveness of dorsal root ganglion pulsed radiofrequency (PRF)in patients with chronic lumbosacral radicular pain and neuropathic features.Study Design: Prospective case series clinical outcome study.Methods: We evaluated 34 patients with lumbosacral neuropathic pain who underwent PRF atthe corresponding level of radicular symptoms distribution (ranging from L3 to S1). Each patientsuffered a single leg-radiating pain with probable neuropathic features (assessed with clinicalgrading) lasting for > 6 months and unresponsive to previous treatments. A multifunctionalPASHA-electrode® was introduced with trans-sacral access through a hollow needle, placed underfluoroscopic guidance into the lumbosacral epidural space and its active tip moved close to thedorsal root ganglion responsible of the clinical symptoms. After connecting the electrode to agenerator, stimulation tests were performed and PRF was started and applied for 240 secondsat a frequency of 2Hz, amplitude of 45 V and a tip temperature between 40 – 42°C. If the paininvolved more than a single nerve root, the electrode was placed at a different segment and theprocedure repeated. Outcome measures included the pain intensity score on a 0 – 10 numericrating scale (NRS) and the Italian Pain Questionnaire (QUID) at pre-treatment, one and 6 monthspost-treatment. P values < 0.05 were considered statistically significant.Results: In comparison with pre-treatment, a significant reduction in pain score was observed inmean NRS either at one and 6 months (P < 0.001). The QUID - Pain Rating Index rank displayed aparallel trend at the first (P < 0.001) and last follow-up (P = 0.01). Moreover, a direct correlationbetween the 2 scales occurred, showing a parallel score decreasing (P < 0.001). Eighteen (52.9%)and 17 (50%) of 34 patients showed pain reduction in NRS > 2 points and > 30%, at one and 6months, respectively.Limitations: The non-controlled design of the study, the patients were heterogeneous, thesmall number of patients, and the duration of follow-up was limited to 6 months.Conclusions: PRF of dorsal root ganglion performed with a multifunctional electrode for > 240seconds appears to be safe and might be more effective than the classic 120 seconds needlemediated approach. Therefore, it may be considered as a valuable tool for the treatment oflumbosacral radicular pain with neuropathic features.Key words: PRF, radicular pain, neuropathic pain, DRG, NRS, PRIr-T, multifunctional electrode