Effect of Intradiscal Monopolar Pulsed Radiofrequency on Chronic Discogenic Back Pain Diagnosed by Pressure-Controlled Provocative Discography: A One Year Prospective Study

OBJECTIVE To investigate the efficacy and safety of percutaneous intradiscal monopolar pulsed radiofrequency (PRF) in patients with chronic disabling discogenic back pain. METHOD Twenty-six subjects (7 males; mean age 43.2 years) with chronic back pain refractory to active rehabilitative management were recruited. All subjects underwent MRI for evaluation of Modic changes, and monopolar PRF (20 min at 60 V) at the center of target lumbar intervertebral disc confirmed by pressure-controlled provocative discography. Clinical outcomes were measured by the visual analogue scale (VAS), Oswestry disability index (ODI), and sitting tolerance time (ST) for 12 months after treatment. Successful clinical outcome was described as a minimum of 2 point reduction in VAS compared with the baseline at each follow-up period. RESULTS The mean VAS for low back pain reduced significantly from 6.4±1.1 at pre-treatment to 4.4±1.9 at 12 months (p<0.05). The mean ODI score was 47.3±15.4 points at pre-treatment and 36.7±19.5 at 12 months (p<0.001). The ST was 27.8±20.4 minutes at pre-treatment and 71.5±42.2 at 12 months (p<0.001). However, successful clinical outcome was achieved at 58%, 50%, and 42%, measured at 3, 6, and 12 months post-treatment. There were no significant relationship between the clinical outcome and Modic changes; no adverse events were recorded. CONCLUSION The results demonstrated that the application of intradiscal monopolar PRF might be relatively effective but limited; successful intervention for chronic refractory discogenic back pain is needed. To achieve the optimal outcome through intradiscal PRF, we suggested further studies about stimulation duration, mode, and intensity of PRF.