A study published in PAIN in 2010 showed remarkable effects of intradiscal methylene blue (MB) injections compared with placebo on pain intensity in patients with chronic discogenic low back pain (CD-LBP). Both groups received lidocaine hydrochloride injections for pain associated with the procedure. We replicated the design of the previously published study and performed a multicenter, double-blind, randomized, placebo-controlled trial to assess whether the extraordinary effects of MB on pain intensity could be confirmed. The primary outcomes were treatment success defined as at least 30% reduction in pain intensity and the Patients' Global Impression of Change 6 months after the intervention. We included 84 patients with CD-LBP of which 14 (35%) in the MB plus lidocaine group showed treatment success compared with 11 (26.8%) in the control group who received placebo plus lidocaine (P = 0.426). Twenty-seven percent of all participants treated with MB stated that their overall health improved much or very much (Patients' Global Impression of Change), vs 25.6% in the placebo group (P = 0.958). We were unable to confirm that intradiscal MB injections are better capable of significantly reducing pain in patients with CD-LBP 6 months after treatment compared with placebo. We observed that over one-quarter of patients receiving only lidocaine injections reported treatment success, which is in contrast with the previously published study. Our results do not support the recommendation of using intradiscal MB injections for patients with CD-LBP.

BackgroundRadiofrequency (RF) treatment of the genicular nerves has the potential to reduce chronic knee pain due to osteoarthritis or persistent postsurgical pain, however, a direct comparison between the two main modalities used, conventional and cooled, is lacking.MethodsThis double blind, non-inferiority, pilot, randomized controlled trial compared the effects of cooled and conventional RF in chronic knee pain patients suffering from osteoarthritis or persistent postsurgical pain after total knee arthroplasty. Patients were randomized following a 1:1 rate. The primary outcome was the proportion of patients with ≥50% pain reduction at 3 months postintervention. Other outcomes were knee pain, functionality, quality of life, emotional health, and adverse events up to 6 months postintervention. Conventional RF treatment was tested for non-inferiority to cooled in reducing knee pain at 3 months follow-up.ResultsForty-nine of 70 patients were included, of which 47 completed a 3-month follow-up. The primary outcome was achieved in 4 of 23 patients treated with conventional RF (17%) vs in 8 of 24 with cooled (33%) (p=0,21). Results from the non-inferiority comparison were inconclusive in relation to the non-inferiority margin. There was no statistically significant difference between secondary outcomes. There were no serious adverse events.ConclusionsBoth conventional and cooled RF treatment reduced pain in the osteoarthritis and persistent postsurgical pain population. This pilot study did not demonstrate statistically significant differences in the proportion of patients experiencing ≥50% pain reduction between techniques. The non-inferiority analysis was inconclusive. These results warrant further research.Trial registration numberNCT03865849.

Introduction Chronic discogenic low back pain (CD‐LBP) is caused by degeneration of the disc due to trauma to the annulus or by unprovoked degeneration, resulting in chronic pain. Spinal cord stimulation (SCS) employing the BurstDR™ waveform has been shown to be an effective treatment in a variety of chronic pain conditions. The aim of this prospective case study was to determine the effect of BurstDR™ SCS on pain relief, disability, and patient satisfaction in a population with CD‐LBP. Methods Seventeen subjects with CD‐LBP received a SCS trial with BurstDR™ stimulation. Patients with >50% pain relief after a trial period of 2 weeks were permanently implanted (n = 15). Patients then rated LBP and leg pain using the numeric rating scale (NRS), Oswestry disability index (ODI), patient global impression of change (PGIC), EQ‐5D quality of life, and painDETECT for neuropathic pain at baseline following trial, 3, 6, and 12 months after permanent implantation. Results Treatment with BurstDR™ SCS resulted in significant reduction of LBP as the NRS was reduced from 71.7 ± 7.3 at baseline to 42.5 ± 18.1 at 12 months. Average pain relief at 12 months was 42.5%. In patients with leg pain (n = 8), pain was significantly reduced from 66.9 ± 8.2 to 11.7 ± 10.4 at 12 months. PainDETECT scores for neuropathic pain significantly reduced from 18.9 ± 4.8 at baseline, and 14.8 ± 3.2 at 12 months. Baseline ODI score significantly reduced from 41.2 ± 12.8 to 25.8 ± 8.6 at 12 months. PGIC scores remained low from 2.6 ± 1.6 at 3 months, 2.5 ± 1.0 at 6 months, and 2.5 ± 1.3 at 12 months. EQ‐5D‐5L rates remained constant from baseline 56.10 ± 23.9 to 68.6 ± 12.9 at 12 months. Conclusion BurstDR™ SCS resulted in significant reduction of back pain, leg pain, and quality of life in patients with CD‐LBP and decreased the level of disability and generated positive patient satisfaction scores.

Pressure rise in adjacent discs does not seem to occur during low-speed flow pressure-controlled lumbar provocation discography. False-positive pain reactions caused by potentially painful adjacent discs are therefore unlikely during pressure-controlled discography.

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