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 prevalence ranging 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 at the corresponding level of radicular symptoms distribution (ranging from L3 to S1). Each patient suffered a single leg-radiating pain with probable neuropathic features (assessed with clinical grading) lasting for > 6 months and unresponsive to previous treatments. A multifunctional PASHA-electrode® was introduced with trans-sacral access through a hollow needle, placed under fluoroscopic guidance into the lumbosacral epidural space and its active tip moved close to the dorsal root ganglion responsible of the clinical symptoms. After connecting the electrode to a generator, stimulation tests were performed and PRF was started and applied for 240 seconds at a frequency of 2Hz, amplitude of 45 V and a tip temperature between 40 - 42°C. If the pain involved more than a single nerve root, the electrode was placed at a different segment and the procedure repeated. Outcome measures included the pain intensity score on a 0 - 10 numeric rating scale (NRS) and the Italian Pain Questionnaire (QUID) at pre-treatment, one and 6 months post-treatment. P values < 0.05 were considered statistically significant. RESULTS In comparison with pre-treatment, a significant reduction in pain score was observed in mean NRS either at one and 6 months (P < 0.001). The QUID - Pain Rating Index rank displayed a parallel trend at the first (P < 0.001) and last follow-up (P = 0.01). Moreover, a direct correlation between 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 6 months, respectively. LIMITATIONS The non-controlled design of the study, the patients were heterogeneous, the small 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 > 240 seconds appears to be safe and might be more effective than the classic 120 seconds needle-mediated approach. Therefore, it may be considered as a valuable tool for the treatment of lumbosacral radicular pain with neuropathic features.