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Abstract
Background and Aims Lumbar radicular pain (LRP) is a challenging clinical symptom. Pulsed radiofrequency (PRF), a neuromodulation technique that uses short pulses of radiofrequency current, is effective in treating pain disorders. This study aimed to determine the intraoperative parameters of PRF of the lumbar dorsal root ganglion (DRG) that are related to clinical effects in patients with LRP.
Methods This was a prospective, double-blind, randomized pilot study. The patients were allocated to two groups, the high-voltage (60 V) and standard- voltage (45 V) groups, according to the preset maximum voltage at which the active tip temperature does not exceed 42°C. The primary outcomes were radicular pain intensity, physical functioning, global improvement and satisfaction with treatment, and adverse events. The assessments were performed until 3 months.
Results The patients in the standard-voltage group showed significant improvements in the numerical rating scale (NRS) (P = 0.007) and Oswestry disability index (ODI) (P = 0.008) scores after PRF; but no difference in the high voltage group. Among the intraoperative parameters, the output current showed a significant negative linear relationship with analgesic efficacy and also a significant association with NRS (P = 0.005, R2 = 0.422) and ODI score (P = 0.004, R2 = 0.427) in the multiple regression analysis. The optimal cut-off value of the output current was 163.5 mA with sensitivity of 87.5%, specificity of 100%, and an area under the receiver operating characteristic curve value of 0.92 (95% CI: 0.76–1.00).
Changes in NRS (A) and ODI score (B) during 3 months between the groups. NRS, numeric rating score; ODI,: Oswestry disability index; PRF, pPulsed radiofrequency
NRS according to the output current. NRS, numeric rating score
ODI score according to the output current. ODI: Oswestry disability index
Conclusions We found that lower output currents during PRF to lumbar DRG associated with higher analgesic effects.