Effect of Intradiscal Methylene Blue Injection for the Chronic Discogenic Low Back Pain: One Year Prospective Follow-up Study

Adverse effects of methylene blue in peripheral neurons: An in vitro electrophysiology and cell culture study

Methylene blue (MB) is an effective treatment for methemoglobinemia, ifosfamide-induced encephalopathy, cyanide poisoning, and refractory vasoplegia. However, clinical case reports and preclinical studies indicate potentially neurotoxic activity of MB at certain concentrations. The exact mechanisms of MB neurotoxicity are not known, and while the effects of MB on neuronal tissue from different brain regions and myenteric ganglia have been examined, its effects on primary afferent neurons from dorsal root ganglia (DRG) have not been studied. Mouse DRG were exposed to MB (0.3-10 μM) in vitro to assess neurite outgrowth. Increasing concentrations of MB (0.3-10 μM) were associated with neurotoxicity as shown by a substantial loss of cells with neurite formation, particularly at 10 μM. In parallel experiments, cultured rat DRG neurons were treated with MB (100 μM) to examine how MB affects electrical membrane properties of small-diameter sensory neurons. MB decreased peak inward and outward current densities, decreased action potential amplitude, overshoot, afterhyperpolarization, increased action potential rise time, and decreased action potential firing in response to current stimulation. MB induced dose-dependent toxicity in peripheral neurons, in vitro. These findings are consistent with studies in brain and myenteric ganglion neurons showing increased neuronal loss and altered membrane electrical properties after MB application. Further research is needed to parse out the toxicity profile for MB to minimize damage to neuronal structures and reduce side effects in clinical settings.

Intradiscal injection for the management of low back pain

Low back pain (LBP) is a common clinical problem and a major cause of physical disability, imposing a prominent socioeconomic burden. Intervertebral disc degeneration (IDD) has been considered the main cause of LBP. The current treatments have limited efficacy because they cannot address the underlying degeneration. With an increased understanding of the complex pathological mechanism of IDD, various medications and biological reagents have been used for intradiscal injection for the treatment of LBP. There is increasing clinical evidence showing the benefits of these therapies on symptomatic relief and their potential for disc repair and regeneration by targeting the disrupted pathways underlying the cause of the disease. A brief overview of the potential and limitations for these therapies are provided in this review, based on the recent and available data from clinical trials and systematic reviews. Finally, future perspectives are discussed.

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.

Single Intradiscal Administration of the Tumor Necrosis Factor-Alpha Inhibitor, Etanercept, for Patients with Discogenic Low Back Pain

OBJECTIVE

To examine the analgesic effect of intradiscal administration of a tumor necrosis factor-αα (TNF-α) inhibitor in patients with discogenic low back pain (LBP).

DESIGN

Prospective, randomized study.

SETTING

Department of Orthopaedic Surgery, Chiba (Japan) University Hospital.

SUBJECTS

Seventy-seven patients diagnosed with discogenic LBP.

METHODS

Discogenic LBP patients were randomly assigned to the etanercept (n = 38; bupivacaine [2 mL] with etanercept [10 mg]) or control (n = 39; bupivacaine [2 mL]) groups. Patients received a single intradiscal injection. Numerical rating scale (NRS) scores for LBP at baseline, 1 day, and 1, 2, 4, and 8 weeks after the injection were recorded. The Oswestry disability index (ODI) scores at baseline and at 4 and 8 weeks after injection were evaluated. Postinjection complications were recorded and evaluated.

RESULTS

In the etanercept group, the NRS scores were significantly lower than in the control group at every time point after the injection for 8 weeks (P < 0.05). Similarly, 4 weeks after the injection, the ODI score was lower in the etanercept group than in the control group (P < 0.05). However, the ODI scores were not significantly different at 8 weeks. Complications were not observed.

CONCLUSIONS

Single intradiscal administration of a TNF-α inhibitor can alleviate intractable discogenic LBP for up to 8 weeks. TNF-α may be involved in discogenic pain pathogenesis. This procedure is a novel potential treatment; longer-term effectiveness trials are required in the future.

Multipotent Mesenchymal Stem Cell Treatment for Discogenic Low Back Pain and Disc Degeneration

Low back pain with resultant loss of function, decreased productivity, and high economic costs is burdensome for both the individual and the society. Evidence suggests that intervertebral disc pathology is a major contributor to spine-related pain and degeneration. When commonly used conservative therapies fail, traditional percutaneous or surgical options may be beneficial for pain relief but are suboptimal because of their inability to alter disc microenvironment catabolism, restore disc tissue, and/or preserve native spine biomechanics. Percutaneously injected Multipotent Mesenchymal Stem Cell (MSC) therapy has recently gained clinical interest for its potential to revolutionarily treat disc-generated (discogenic) pain and associated disc degeneration. Unlike previous therapies to date, MSCs may uniquely offer the ability to improve discogenic pain and provide more sustained improvement by reducing disc microenvironment catabolism and regenerating disc tissue. Consistent treatment success has the potential to create a paradigm shift with regards to the treatment of discogenic pain and disc degeneration.

Single intradiscal injection of the interleukin-6 receptor antibody tocilizumab provides short-term relief of discogenic low back pain; prospective comparative cohort study

BACKGROUND

Inflammatory cytokines, such as interleukin-6 and tumor necrosis factor-α, are gaining attention as important etiologic factors associated with discogenic low back pain. We conducted a prospective cohort study to evaluate the efficacy and safety of intradiscal injection of the interleukin-6 receptor antibody tocilizumab in patients with discogenic low back pain.

METHODS

Thirty-two consecutive patients were intradiscally injected with 2 mL of 0.5% bupivacaine (control group). Another 31 consecutive patients were intradiscally injected with 40 mg tocilizumab and 1-2 mL of 0.5% bupivacaine (tocilizumab group) at the same time. Prior to treatment, the vertebral origin of low back pain was confirmed in all patients based on pain provocation during discography and pain relief with 1 mL of 1% xylocaine. Numeric rating scale and Oswestry disability index scores were used to evaluate pain level before and after treatment between the 2 groups. The association between pain relief with tocilizumab and intervertebral disc degeneration grade was also determined.

RESULTS

At the end of the study (8 weeks after treatment), 30 patients in each group were evaluable. In the tocilizumab group, numeric rating scale and Oswestry disability index scores improved significantly at 2 and 4 weeks after treatment, respectively. Intervertebral disc degeneration was not associated with improvement of numeric rating scale score in the tocilizumab group. Local infection (i.e., discitis) was observed in 1 patient in the tocilizumab group.

CONCLUSIONS

The results demonstrate the clinical relevance of interleukin-6 in discogenic low back pain. Intradiscal tocilizumab injection was shown to exert a short-term analgesic effect in patients with discogenic low back pain. Further research is required to determine the long-term effects of intradiscal tocilizumab therapy in patients with discogenic low back pain.

Effects of methylene blue on postoperative low-back pain and functional outcomes after lumbar open discectomy: a triple-blind, randomized placebo-controlled trial

OBJECT

Despite advances in surgical and anesthesiology techniques, many patients continue to experience postoperative pain after lumbar disc operations. This study aims to investigate the effects of methylene blue (MB) on preventing postoperative low-back pain (LBP) with or without radicular pain and improving the quality of life (QOL) in patients undergoing lumbar open discectomy.

METHODS

This is a prospective, randomized, triple-blind, placebo-controlled clinical trial, which was conducted at Shiraz University of Medical Sciences between July 2011 to January 2012. Of a total of 130 patients, 115 were eligible for participation; 56 received 1 ml of MB solution at a concentration of 0.5% (MB group) and 59 received an equivalent volume of normal saline (control group). Primary outcomes were the control of LBP with or without radicular pain, which was evaluated preoperatively and at 24 hours and 3 months after surgery with the use of a visual analog scale (VAS), and the improvement of QOL, which was assessed preoperatively and 3 months postoperatively by means of the Persian translation of the Oswestry Disability Index questionnaire.

RESULTS

The mean VAS scores for LBP were significantly lower in the MB group compared with the control group at 24 hours (1.25 ± 0.97 vs 2.80 ± 0.69, p < 0.001) and 3 months (1.02 ± 1.29 vs 2.07 ± 1.10, p = 0.019) after treatment. The mean radicular pain scores decreased significantly in the 2 groups at 24 hours after surgery, but the mean radicular pain score was significantly lower in the MB-treated patients than the control group. However, the difference between radicular pain scores in the MB group (1 ± 1.1) and the control group (1.2 ± 1) was not statistically significant (p = 0.64). The reduction in LBP was greater in the MB group than the control group (8.11 ± 1.74 vs 6.07 ± 1.52, p = 0.023, CI 95% −1.37 to −0.10). The functional QOL improved significantly 3 months after the operation in both groups (p < 0.001). Moderate disability occurred more frequently in the control group than in the MB group (14.5% vs 7.7%, p = 0.004). No toxicity, adverse effects, or complications were found in the group of patients treated with MB injection.

CONCLUSIONS

A single dose of MB (1 ml 0.5%) for coating the dura and surrounding tissues (facet and muscle) shows promising results in terms of safety, reduction of postoperative pain, and functional outcome compared with placebo.

Evaluation and Treatment of Low Back Pain: A Clinically Focused Review for Primary Care Specialists

Low back pain (LBP) is a leading cause of disability worldwide. In the absence of a classification system for pain syndromes, classification of LBP on the basis of the distribution of pain as axial (pain generally localized to the low back) or radicular neuropathic (pain radiating to the lower extremities) is relevant to clinical practice because the distribution of pain is often a corollary of frequently occurring disease processes involving the lumbar spine. Common sources of axial LBP include the intervertebral disc, facet joint, sacroiliac joint, and paraspinal musculature, whereas common sources of radicular pain include a herniated intervertebral disc and spinal stenosis. The accuracy of historical and physical examination findings has been established for sacroiliac joint pain, radiculopathy, and lumbar spinal stenosis. However, the accuracy of similar data, so-called red flags, for identifying the underlying medical sources of LBP has been overstated. Diagnostic imaging studies can be useful, and adherence to established guidelines can protect against overuse. Multiple pharmacological trials exist for the management of LBP; however, the long-term outcomes of commonly used drugs are mixed. For carefully selected patients with axial LBP, radiofrequency denervation techniques can provide sustained pain relief. In patients with radicular pain, transforaminal epidural steroid injections may provide short-term pain relief, but neurostimulation may confer more enduring benefits of refractory symptoms. Pain-related indications for commonly performed operations include spinal decompression for radicular symptoms as well as spinal fusion or disc prosthesis for discogenic LBP. Physical modalities and psychological treatments can improve pain and functioning, but patient preferences may influence treatment adherence.

Current trends in biologics delivery to restore intervertebral disc anabolism

Low back pain is generally attributed to intervertebral disc (IVD) degeneration. This is a multifactorial disease induced by genetic and environmental factors and that progresses with aging. Disc degeneration is characterized by a limited ability of IVD cells to produce functional matrix while producing abnormal amounts of matrix-degrading enzymes. The prolonged imbalance between anabolism and catabolism in degenerative discs alters their composition and hydration. In turn, this results in increased angiogenesis and the loss of the disc's ability to maintain its aneural condition. Inflammation in the IVD, in particular the presence of pro-inflammatory cytokines, was found to favor innervation and also sensitization of the nociceptive pathways, thereby exacerbating degenerative symptoms. In this review, we discuss anti-inflammatory approaches to encounter disc catabolism, potential treatments to lower discogenic pain and pro-anabolic approaches in the form of protein delivery, gene therapy and cell delivery, to trigger regeneration in the IVD.

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.

MALDI-TOF-MS serum protein profiling for developing diagnostic models and identifying serum markers for discogenic low back pain

Background

The identification of the cause of chronic low back pain (CLBP) represents a great challenge to orthopedists due to the controversy over the diagnosis of discogenic low back pain (DLBP) and the existence of a number of cases of CLBP of unknown origin. This study aimed to develop diagnostic models to distinguish DLBP from other forms of CLBP and to identify serum biomarkers for DLBP.

Methods

Serum samples were collected from patients with DLBP, chronic lumbar disc herniation (LDH), or CLBP of unknown origin, and healthy controls (N), and randomly divided into a training set (n = 30) and a blind test set (n = 30). Matrix-assisted laser desorption ionization time-of-flight mass spectrometry was performed for protein profiling of these samples. After the discriminative ability of two most significantly differential peaks from each two groups was assessed using scatter plots, classification models were developed using differential peptide peaks to evaluate their diagnostic accuracy. The identity of peptides corresponding to three representative differential peaks was analyzed.

Results

The fewest statistically significant differential peaks were identified between DLBP and CLBP (3), followed by CLBP vs. N (5), DLBP vs. N (9), LDH vs. CLBP (20), DLBP vs. LDH (23), and LDH vs. N (43). The discriminative ability of two most significantly differential peaks was poor in classifying DLBP vs. CLBP but good in classifying DLBP vs. LDH. The accuracy of models for classification of DLBP vs. CLBP was not very high in the blind test (forecasting ability, 67.24%; sensitivity, 70%), although a higher accuracy was observed for classification of DLBP vs. LDH and LDH vs. N (forecasting abilities, ~90%; sensitivities, >90%). A further investigation of three representative differential peaks led to the identification of two peaks as peptides of complement C3, and one peak as a human fibrinogen peptide.

Conclusions

Our findings benefit not only the diagnosis of CLBP but also the understanding of the differences between different forms of DLBP. The ability to distinguish between different causes of CLBP and the identification of serum biomarkers may be of great value to diagnose different causes of DLBP and predict treatment efficacy.