Intradiscal methylene blue injection was not found to alleviate pain in patients with chronic diskogenic low back pain (CD-LBP), according to a study published in PAIN.
Researchers sought to replicate the results from a multicenter double blind trial published in 2010, in which intradiscal methylene blue injections were found to reduce pain intensity and improve overall health in patients with CD-LBP.
A total of 81 patients with CD-LBP (age 22-65 years) treated at 4 interventional pain centers were randomly assigned to receive 1 mL methylene blue plus 0.5 mL lidocaine hydrochloride 2% (n=40) or 1 mL isotonic saline plus 0.5 mL of lidocaine hydrochloride 2% (n=41). Study participants were assessed at baseline, at 6 weeks, and at 3 and 6 months. Baseline characteristics were similar between groups. The trial’s primary outcome was average pain at 6 months, self-assessed by participants 3 times daily over 4 days using a numeric rating scale.
A total of 25 patients from the entire cohort (30.9% ) reported a reduction ≥30% at 6 months from baseline levels, including 14 patients who had received methylene blue injections and 11 patients in the placebo group (P =0.43). Overall health was reported to be “much” or “very much” improved by 25% and 24.4% of participants treated with methylene blue and placebo, respectively, 6 months after treatment (P =0.96). Pain reduction of ≥30% combined with “much” or “very much” improved health was reported by 22.5% and 19.5% of participants who had received methylene blue and placebo, respectively.
The researchers reported small sample size as a limitation of their study.
“Our results do not support the recommendation of using intradiscal [methylene blue] injection as a treatment therapy of choice for patients with [CD-LBP],” concluded the study authors. “We recommend further research to study the exact mechanism of [CD-LBP] and to define the specific characteristics of [patients with CD-LBP] to determine whether intradiscal injections may be a treatment option.”
Kallewaard JW, Wintraecken VM, Veerle M, et al. A multicenter randomized controlled trial on the efficacy of intradiscal methylene blue injection for chronic discogenic low back pain: The IMBI study [published online January 3, 2019]. PAIN. doi: 10.1097/j.pain.0000000000001475