A cure for back pain?

Methylene Blue Application to Lessen Pain: Its Analgesic Effect and Mechanism

Methylene blue (MB) is a cationic thiazine dye, widely used as a biological stain and chemical indicator. Growing evidence have revealed that MB functions to restore abnormal vasodilation and notably it is implicated even in pain relief. Physicians began to inject MB into degenerated disks to relieve pain in patients with chronic discogenic low back pain (CDLBP), and some of them achieved remarkable outcomes. For osteoarthritis and colitis, MB abates inflammation by suppressing nitric oxide production, and ultimately relieves pain. However, despite this clinical efficacy, MB has not attracted much public attention in terms of pain relief. Accordingly, this review focuses on how MB lessens pain, noting three major actions of this dye: anti-inflammation, sodium current reduction, and denervation. Moreover, we showed controversies over the efficacy of MB on CDLBP and raised also toxicity issues to look into the limitation of MB application. This analysis is the first attempt to illustrate its analgesic effects, which may offer a novel insight into MB as a pain-relief dye.

Methylene blue induces an analgesic effect by significantly decreasing neural firing rates and improves pain behaviors in rats

Methylene blue (MB) is a blue cationic thiazine dye and currently used in different medical settings. Notably, there have been several attempts to introduce MB for attenuating pain in the last decade. Some clinical studies reported remarkable results, which, however, have been much debated. In addition, accumulating evidence have revealed that MB diminishes voltage-gated sodium channel currents. Accordingly, in the present study, we conducted in vivo experiments, including in vivo single nerve recording and behavioral test, to investigate whether MB dampens neural firing rates and ultimately contributes to pain relief. As a result, neural firing rates significantly decreased and finally converged to zero after MB administration. This event lasted longer than that of lidocaine and was dose-dependently modulated. Furthermore, there was a marked improvement in pain behaviors. The withdrawal threshold and latency of hind paws significantly rose post-MB administration. Therefore, these results demonstrate that MB lessens pain by significantly weakening neural excitability, which implies a strong possibility that this dye may be developed as a pain-relieving medication in the future. This is the first in vivo study to elucidate the effect of MB on nerves and pain relief.

Efficacy, Safety, and Predictors of Intradiscal Methylene Blue Injection for Discogenic Low Back Pain: Results of a Multicenter Prospective Clinical Series

STUDY DESIGN

Prospective clinical study of intradiscal methylene blue injection for the treatment of lumbar discogenic pain.

OBJECTIVE

The objective of this study was to collect information about efficacy, safety, and acceptability of the intervention, gain and burden of outcome measures, and sample size assumptions for a potential following randomized controlled trial (RCT). If the pilot study demonstrates that this treatment is potentially effective and safe, and the methods and procedures used in this study are feasible, a RCT follows.

SUMMARY OF BACKGROUND DATA

Low back pain (LBP) is a highly common problem with a lifetime prevalence of more than 70%. A substantial part of chronic LBP is attributable to degenerative changes in the intervertebral disc. A recently published RCT assessing the treatment intradiscal injection of methylene blue for chronic discogenic LBP, showed exceptionally good results.

METHODS

Patients were selected on clinical criteria, magnetic resonance imaging, and a positive provocative discogram. The primary outcome measure was mean pain reduction at 6 months.

RESULTS

Fifteen consecutive patients with chronic lumbar discogenic pain enrolled in a multicenter prospective case series in two interventional pain treatment centers in the Netherlands. Six months after the intervention, 40% of the patients claimed at least 30% pain relief. In patients who responded, physical function improved and medication use diminished. We observed no procedural complications or adverse events. Predictors for success were Pfirrmann grading of 2 or less and higher quality of life mental component scores.

CONCLUSIONS

Our findings of 40% positive respondents, and no complications, give reason to set up a randomized, double-blind, placebo-controlled, trial.

The effectiveness of sub-group specific manual therapy for low back pain: a systematic review

BACKGROUND

Manual therapy is frequently used to treat low back pain (LBP), but evidence of its effectiveness is limited. One explanation may be sample heterogeneity and inadequate sub-grouping of participants in randomized controlled trials (RCTs) where manual therapy has not been targeted toward those likely to respond.

OBJECTIVES

To determine the effectiveness of specific manual therapy provided to sub-groups of participants identified as likely to respond to manual therapy.

DATA SOURCES

A systematic search of electronic databases of MEDLINE, EMBASE, CINAHL, and the Cochrane Central Register of Controlled trials (CENTRAL). TRIAL ELIGIBILITY CRITERIA: RCTs on manual therapy for participants identified as belonging to a sub-group of LBP likely to respond to manual therapy were included. TRIAL APPRAISAL AND SYNTHESIS METHODS: Identified trials were assessed for eligibility. Data from included trials were extracted by two authors independently. Risk of bias in each trial was assessed using the PEDro scale and the overall quality of evidence rated according to the GRADE domains. Treatment effect sizes and 95% confidence intervals were calculated for pain and activity.

RESULTS

Seven RCTs were included in the review. Clinical and statistical heterogeneity precluded meta-analysis. Significant treatment effects were found favouring sub-group specific manual therapy over a number of comparison treatments for pain and activity at short and intermediate follow-up. However, the overall GRADE quality of evidence was very low.

CONCLUSIONS

This review found preliminary evidence supporting the effectiveness of sub-group specific manual therapy. Further high quality research on LBP sub-groups is required.