Chronic low back pain, bacterial infection and treatment with antibiotics

Explainable Machine Learning Models for Prediction of Surgical Site Infection After Posterior Lumbar Fusion Surgery Based on Shapley Additive Explanations

OBJECTIVE

This study aims to develop machine learning (ML) models combined with an explainable method for the prediction of surgical site infection (SSI) after posterior lumbar fusion surgery.

METHODS

In this retrospective, single-center study, a total of 1016 consecutive patients who underwent posterior lumbar fusion surgery were included. A comprehensive dataset was established, encompassing demographic variables, comorbidities, preoperative evaluation, details related to diagnosed lumbar disease, preoperative laboratory tests, surgical specifics, and postoperative factors. Utilizing this dataset, 6nullML models were developed to predict the occurrence of SSI. Performance evaluation of the models on the testing set involved several metrics, including the receiver operating characteristic curve, the area under the receiver operating characteristic curve, accuracy, recall, F1 score, and precision. The Shapley Additive Explanations (SHAP) method was employed to generate interpretable predictions, enabling a comprehensive assessment of SSI risk and providing individualized interpretations of the model results.

RESULTS

Among the 1016 retrospective cases included in the study, 36 (3.54%) experienced SSI. Out of the six models examined, the Extreme Gradient Boost model demonstrated the highest discriminatory performance on the testing set, achieving the following metrics: precision (0.9000), recall (0.8182), accuracy (0.9902), F1 score (0.8571), and area under the receiver operating characteristic curve (0.9447). By utilizing the SHAP method, several important predictors of SSI were identified, including the duration of indwelling jugular vein catheter, blood urea nitrogen levels, total protein levels, sustained fever, creatinine levels, triglycerides levels, monocyte count, diabetes mellitus, drainage time, white blood cell count, cerebral infarction, estimated blood loss, prealbumin levels, Prognostic Nutritional Index, low back pain, posterior fusion score, and osteoporosis.

CONCLUSIONS

ML-based prediction tools can accurately assess the risk of SSI after posterior lumbar fusion surgery. Additionally, ML combined with SHAP could provide a clear interpretation of individualized risk prediction and give physicians an intuitive comprehension of the effects of the model's essential features.

mNGS technique was used to analyze the microbiome structure of intervertebral disc tissue in 99 patients with degenerative disc disease

OBJECTIVE

Whether bacterial hypotoxic infection in the intervertebral disc is the cause of disc degenerative disease (DDD) is controversial. The mNGS technique can provide valuable insights by obtaining more comprehensive evidence of the presence of bacteria in the intervertebral disc. This study was designed to analyze the characteristics of intervertebral microbiome structure in patients with lumbar disc degenerative disease and its correlation with clinical indicators.

METHODS

A total of 104 patients with lumbar disc degenerative diseases were included in this study. The surgically removed lumbar intervertebral disc tissues were collected for clinical culture and metagenomic second-generation sequencing (mNGS), and the consistency of the two microbial detection methods was compared.According to the collected clinical information, patients were grouped according to the modified Pfirrmann grading, Modic typing and age, and the differences of microbial communities detected by mNGS among different groups were compared, including α diversity analysis, β diversity analysis, species abundance difference analysis, etc. Spearman correlation between clinical features and generic relative abundance was calculated.

RESULTS

The effective culture results of 104 intervertebral disc tissue samples were only 19 cases positive, with a positive rate of 18.3% (19/104), and the mNGS detection results were positive in 99 cases, with a positive rate of 95.2% (99/104). According to the 19 samples with positive culture, nearly half 47.4% (9/19) of staphylococcus species were positive, and all the positive species were basically epidermal common colonization species or environmental common bacteria. At the same time, we conducted two times of mNGS sequencing for these 19 samples, and the consistency rate between the two sequencing results and the culture results was 84.2% (16/19). According to the results of mNGS detection, 250 species from 110 genera were detected in 99 positive samples. The results of group analysis showed that patients with lower degree of disc degeneration (modified Pfirrmann ≤ 4) and young patients (age < 45 years) had more abundant microbial communities in disc tissue (P < 0.05). Correlation analysis showed that there was a positive correlation between Arcobacter skirrowii and improved Pfirrmann classification at the species level (P < 0.01). There was a negative correlation between pseudomonas thermotolerans and modified Pfirrmann classification (P < 0.05). There was a positive correlation between Staphylococcus hominis and Modic typing scores (P < 0.05). Staphylococcus arlettae was negatively correlated with age (P < 0.05). At the genus level, Arcobacter had a significant positive correlation with the modified Pfirrmann grade and Modic classification (P < 0.05), Corynebacterium had a significant negative correlation with the modified Pfirrmann grade (P < 0.05), and Pseudomonas had a significant negative correlation with age (P < 0.05). After our follow-up of six months to one year, two of the patients included in this study eventually developed severe lumbar disc infection, and the rest did not develop infection.

CONCLUSIONS

This study proves that hypotoxic infection may be involved in the degeneration of intervertebral disc, and the bacterial species that cause this occult infection may be more abundant than previously thought. In addition, there was a significant correlation between the biome structure of these bacteria and clinical indicators. The hypothesis of the cause of this insidious infection has the potential to change the way the disease is treated.

Hospital-Treated Infections and 15-year Incidence of Musculoskeletal Disorders: A Large Population-Based Cohort Study

Background

Basic science evidence reveals interactions between the immune and bone systems. However, population studies linking infectious diseases and musculoskeletal (MSK) disorders are limited and inconsistent. We aimed to examine the risk of six main MSK disorders (osteoarthritis, rheumatoid arthritis, osteoporosis, gout, low back pain, and neck pain) following hospital-treated infections in a large cohort with long follow-up periods.

Methods

We analysed data from 502,409 UK Biobank participants. Participants free of specific MSK disorders at baseline were included in each analysis. Hospital-treated infections before baseline were identified using national inpatient data, while incident MSK outcomes were ascertained from inpatient records, primary care, and death registers. Participants with prior infections were propensity score matched (1:5) with those without. Hazard ratios (HRs) and absolute rate differences (ARDs) with 95% confidence intervals (CIs) were calculated using Cox proportional hazards models. To assess potential reverse causality due to delayed diagnosis of preexisting illness, analyses were repeated excluding MSK disorder cases that occurred within the first 5 and 10 years post-baseline.

Results

A hospital-treated infection was associated with increased risks of all six MSK disorders, with particularly strong associations for osteoporosis (HR, 1.55 [1.48-1.63]; ARD, 1.48 [95% CI 1.29-1.68] per 1000 person-years) and rheumatoid arthritis (HR, 1.53 [1.41-1.65]; ARD, 0.58 [0.46-0.71] per 1000 person-years), while other disorders showed HRs of 1.28-1.32. Bacterial and viral infections showed similar associations, with MSK infections (generally stronger risk) and other locations both linked to increased risks. Associations remained significant even for incident cases that occurred more than 10 years post-baseline.

Conclusion

Hospital-treated infections are associated with long-term MSK disorder risks, regardless of pathogen type or disorder nature (inflammatory or degenerative). Long-term monitoring and care for MSK health in patients with prior hospital-treated infections are recommended.

Preclinical development and characterisation of PP353, a formulation of linezolid for intradiscal administration

Introduction

Bacterial infection of the intervertebral disc can lead to vertebral endplate edema known as Modic changes, with associated chronic low back pain. Oral antimicrobial therapy has shown efficacy but relies on prolonged dosing and may not be optimal in terms of patient outcome, side effects, or antibiotic stewardship. There is no antibiotic formulation approved for intradiscal administration. Here, we describe the development and preclinical characterization of a formulation of linezolid, a suspension of 50 mg/mL micronized powder, for intradiscal administration.

Methods

Micronization, particle size analysis, Franz cell diffusion assays, ex vivo bioassay, and estimates of gelling temperature were used to optimize the composition and properties of the formulation. Performance of the formulation was assessed using sheep to characterize the pharmacokinetics and a model of intradiscal infection was developed to demonstrate efficacy. Suitability for human administration was demonstrated in a Good Laboratory Practice (GLP) local tolerance study.

Results

Micronized linezolid, formulated as a powder suspension using a vehicle containing poloxamer 407 and iohexol, provided a temperature-dependent radio-opaque gel that was suitable for image-guided percutaneous intradiscal administration. Efficacy in a sheep model of intradiscal Staphylococcus aureus infection was demonstrated. The formulation provides a high level of sheep disc tissue exposure, with Cmax of 6500 μg/g and limited systemic exposure, with a plasma Cmax of 0.04 μg/mL per 0.1 mL dose (5 mg of linezolid). Deconvolution of plasma linezolid pharmacokinetics correlated with linezolid remaining in the disc over time. Observations from a GLP local tolerance study with the linezolid formulation were of a minor nature and related to the intradiscal administration procedure.

Conclusions

Linezolid can be formulated for image-guided percutaneous intradiscal administration. The formulation is now in a Phase 1b clinical trial to evaluate safety, pharmacokinetics, and efficacy in patients with CLBP and suspected bacterial infection.

Landscape of the Lumbar Cartilaginous End Plate Microbiota and Metabolites in Patients with Modic Changes

BACKGROUND

Modic changes (MCs), vertebral end plate and bone marrow damage observed by magnetic resonance imaging, are an independent risk factor for low back pain. The compositions of and interaction between microbiota and metabolites in the lumbar cartilaginous end plates (LCEPs) of patients with MCs have not been identified.

METHODS

Patients with lumbar disc degeneration who were undergoing lumbar spinal fusion surgery were recruited between April 2020 and April 2021. LCEPs were collected for 16S rRNA sequencing and liquid chromatography-mass spectrometry (LC/MS)-based targeted metabolomic profiling. Of the 54 patients recruited, 24 had no MCs and 30 had changes classified as Modic type 2 or 3. The primary goal was to identify specific genera of microbiota associated with MCs, and secondary goals included investigating differences in metabolites between patients with and without MCs and exploring the correlation between these metabolites and microorganisms.

RESULTS

Investigation of the microbiota community structure revealed that both alpha diversity and beta diversity were significantly different between patients with and without MCs, and the abundances of 26 genera were significantly different between these 2 groups. Metabolomic analysis revealed that 26 metabolites were significantly different between the 2 groups. The unsaturated fatty acid pathway was found to be the main pathway related to MCs. Multiomic correlation analysis suggested that Caulobacteraceae (unclassified) and Mycobacterium, Clostridium, Blautia, and Bifidobacterium at the genus level were linked to dysregulation of fatty acid metabolism, contributing to the pathogenesis of MCs.

CONCLUSIONS

Our study represents a foundational effort to examine the landscape of the microbiota and metabolites in patients with MCs, informing future studies on the pathogenesis of and targeted therapy for MCs.

LEVEL OF EVIDENCE

Prognostic Level II . See Instructions for Authors for a complete description of levels of evidence.

Bacterial identification in herniated intervertebral discs: a prospective cohort study

BACKGROUND CONTEXT

Reports of Cutibacterium acnes isolated in cultures of intervertebral disc samples suggest it as possibly responsible for inflammatory conditions causing Modic changes on spinal magnetic resonance imaging (MRI).

PURPOSE

Our objective was to investigate the prevalence of C. acnes in samples of intervertebral disc of patients with lumbar disc herniation; to investigate prognostic factors and the relationship of Modic changes with infection 1 year after microdiscectomy.

STUDY DESIGN

Prospective cohort study.

PATIENT SAMPLE

In this single-center study, patients consecutively operated on for disc herniation had samples of the disc, multifidus muscle and ligamentum flavum (as an indication of contamination) extracted for culture.

OUTCOME MEASURES

Age, sex, alcohol and tobacco consumption, body mass index; function, pain, and Modic chances in MRI before surgery and MRI 1 year later; rate of disc, muscle and ligament infection (primary outcome); diabetes and corticoid use (confoundings).

METHODS

The protruded disc, muscle and ligament samples were sent for culture analysis in up to 30 minutes. A subsample of 17 patients underwent next-generation sequencing (NGS) molecular analysis too. We performed descriptive analysis and comparison of groups of patients with and without infection or contamination using Student's t, Mann-Whitney, chi-square, or Fisher's exact tests as appropriate, and pre- and postsurgical comparisons with the Wilcoxon test.

RESULTS

From January 2018 to September 2019, 112 patients underwent open lumbar microdiscectomy, 67 (59.8%) men. Cultures showed 7 (6.3%) positive cases in the disc (2 with C. acnes), 3 (2.7%) in the ligament, and 12 (10, 7%) in muscle. No evidence of a difference in Modic alterations pre- or postoperatively was found between patients with and without positive culture 1 year after surgery. No association was found between culture positivity and functional or pain differences either. NGS results were all negative for C. acnes.

CONCLUSIONS

We identified infective bacterial presence in the herniated disc in less than 2% of patients with disc herniation. C. acnes was not identified in any disc microbiome analysis. No significant association was observed between positivity for tissue infection and any clinical prognostic factor.

Does hydrogen peroxide help mitigate the incidence of Cutibacterium acnes in cervical spine surgeries?

Background

Surgical site infection (SSI) is a common yet serious complication of cervical spine surgery. While initially thought to be clinically insignificant, Cutibacterium acnes (C. acnes) is an important cause of infection. The purpose of this study was to investigate the ability of a hydrogen peroxide (H2O2) application during standard presurgical skin preparation to reduce the burden of C. acnes in patients undergoing cervical spine surgery.

Methods

This was a retrospective review of prospectively collected data. Subjects were randomly assigned to either standard surgical preparation plus H2O2 (experimental) or without H2O2 (control). Prescrub, postscrub, and dermal cultures were obtained to assess the C. acnes burden after cultures on an aerobic and anaerobic growth medium were held for 21 days. Multivariate analysis was conducted to determine factors associated with presence of C. acnes. Outcome measures included the results of intraoperative cultures and the development of a SSI within 90 days postoperatively.

Results

Patients (n=86) undergoing elective 2- or 3-level fusion via anterior approach were included. Prior to application of the antiseptic solution, 65% (28/43) of the experimental cohort and 77% (33/43) of the control cohort had positive C. acnes cultures (p=.34). Following application of antiseptic solution, there were no differences in positive C. acnes culture rates between the experimental and control cohorts in the epidermal (30% vs. 28%, p=1.00) or dermal (40% vs. 42%, p=1.00) cultures. No differences in the rates of C. acnes eradication from preantiseptic to postantiseptic application occurred for epidermal (p=1.00) or dermal (p=1.00) skin layers. None of the factors were associated with positive C. acnes epidermal cultures on multivariable logistic regression analysis (p>.05).

Conclusions

While there is potential for H2O2 to reduce the positive culture rate of C. acnes in cervical spine patients, no difference was seen when compared to standard surgical skin preparation.

Roles of Chemokines in Intervertebral Disk Degeneration

PURPOSE OF REVIEW

Intervertebral disc degeneration is the primary etiology of low back pain and radicular pain. This review examines the roles of crucial chemokines in different stages of degenerative disc disease, along with interventions targeting chemokine function to mitigate disc degeneration.

RECENT FINDINGS

The release of chemokines from degenerated discs facilitates the infiltration and activation of immune cells, thereby intensifying the inflammatory cascade response. The migration of immune cells into the venous lumen is concomitant with the emergence of microvascular tissue and nerve fibers. Furthermore, the presence of neurogenic factors secreted by disc cells and immune cells stimulates the activation of pain-related cation channels in the dorsal root ganglion, potentially exacerbating discogenic and neurogenic pain and intensifying the degenerative cascade response mediated by chemokines. Gaining a deeper comprehension of the functions of chemokines and immune cells in these processes involving catabolism, angiogenesis, and injury detection could offer novel therapeutic avenues for managing symptomatic disc disease.

Personalized assessment and management of non-specific low back pain

BACKGROUND AND OBJECTIVE

Low back pain (LBP), and in particular non-specific low back pain (NSLBP), which accounts for approximately 90% of LBP, is the leading cause of years lived with disability worldwide. In clinical trials, LBP is often poorly categorized into 'specific' versus 'non-specific' and 'acute' versus 'chronic' pain. However, a better understanding of the underlying pain mechanisms might improve study results and reduce the number of NSLBP patients.

DATABASES AND DATA TREATMENT

Narrative review.

RESULTS

NSLBP is a multi-dimensional, biopsychosocial condition that requires all contributing dimensions to be assessed and prioritized. Thereby, the assessment of the contribution of nociceptive, neuropathic and nociplastic pain mechanisms forms the basis for personalized management. In addition, psychosocial (e.g. anxiety, catastrophizing) and contextual factors (e.g. work situation) as well as comorbidities need to be assessed and individually weighted. Personalized treatment of NSLBP further requires individually choosing treatment modalities, for example, exercising, patient education, cognitive-behavioural advice, pharmacotherapy, as well as tailoring treatment within these modalities, for example, the delivery of tailored psychological interventions or exercise programs. As the main pain mechanism and psychosocial factors may vary over time, re-assessment is necessary and treatment success should ideally be assessed quantitatively and qualitatively.

CONCLUSIONS

The identification of the main contributing pain mechanism and the integration of the patients' view on their condition, including beliefs, preferences, concerns and expectations, are key in the personalized clinical management of NSLBP. In research, particular importance should be placed on accurate characterization of patients and on including outcomes relevant to the individual patient.

SIGNIFICANCE STATEMENT

Here, a comprehensive review of the challenges associated with the diagnostic label 'non-specific low back pain' is given. It outlines what is lacking in current treatment guidelines and it is summarized what is currently known with respect to individual phenotyping. It becomes clear that more research on clinically meaningful subgroups is needed to best tailor treatment approaches.

The disc-endplate-bone-marrow complex classification: progress in our understanding of Modic vertebral endplate changes and their clinical relevance

BACKGROUND CONTEXT

The disc, endplate (EP), and bone marrow region of the spine form a single anatomical and functional interdependent unit; isolated degeneration of any one structure is rare. Modic changes (MC), however, are restricted to the subchondral bone alone and based on only T1 and T2 sequences of MRI. This results in poor reliability in differentiating fat from edema and hence may give a false impression of disease inactivity.

PURPOSE

To study the changes in disc, endplate, and bone marrow as a whole in degeneration and propose a classification based on the activity status of this complex with the addition of STIR MRI sequences.

STUDY DESIGN

Observational cohort.

PATIENT SAMPLE

Patients with isolated brain, cervical, or thoracic spine injury and patients with low back pain (LBP) who underwent MRI formed the control and study groups, respectively.

OUTCOME MEASURES

Demographic data, the prevalence of MC and disc-endplate-bone marrow classification (DEBC) changes, EPs undergoing reclassification based on DEBC, and comparison of the prevalence of MC, DEBC, H+modifier and DEBC with H+concordance between control and LBP group. The study determined the risk of LBP patients undergoing surgery as well as the incidence of postoperative infection based on DEBC changes. Significance was calculated by binomial test and chi-square test with the effect size of 0.3 to 0.5. Prevalence and association of outcome were calculated by Altman's odds ratio with the 95% CI and the scoring of z statistics. Logistic expression was plotted for independent variables associated with each class of both Modic and DEBC against dependent variables surgery and nonsurgery.

METHODS

Lumbar segments in both groups were assessed for MC types. The DEBC classification was developed with the addition of STIR images and studying the interdependent complex as a whole: type-A: acute inflammation; type-B: chronic persistence; type-C: latent and type-D: inactive. Modifier H+ was added if there was disc herniation. The classification was compared with MC and correlated to clinical outcomes.

RESULTS

A total of 3,560 EPs of 445 controls and 8,680 EPs in 1,085 patients with LBP were assessed. Four nonMC, 560 MC-II, and 22 MC-III EPs were found to have previously undetected edema in STIR (n=542) or hyperintensity in discs (n=44) needing reclassification. The formerly undescribed type-B of DEBC, representing a chronic persistent activity state was the most common (51.8%) type. The difference between the control and LBP of H+(12% vs 28.8%) and its co-occurrence with DEBC type 1.1% vs 23.3%) was significant (p<.0001). The odds ratio for the need for surgery was highest (OR=5.2) when H+ and DEBC type change co-occurred. Postoperative deep infection (as determined by CDC criteria) was 0.47% in nonDEBC, compared with 2.4% in patients with DEBC (p=.002), with maximum occurrence in type-B.

CONCLUSION

Classification based on the classic MC was found to need a reclassification in 586 EPs showing the shortcomings of results of previous studies. Considering the DEBC allowed better classification and better predictability for the need for surgical intervention and incidence of postoperative infection rate than MC.

Antibiotic use in spine surgery: A narrative review based in principles of antibiotic stewardship

Background

A growing emphasis on antibiotic stewardship has led to extensive literature regarding antibiotic use in spine surgery for surgical prophylaxis and the treatment of spinal infections.

Purpose

This article aims to review principles of antibiotic stewardship, evidence-based guidelines for surgical prophylaxis and ways to optimize antibiotics use in the treatment of spinal infections.

Methods

A narrative review of several society guidelines and spine surgery literature was conducted.

Results

Antibiotic stewardship in spine surgery requires multidisciplinary investment and consistent evaluation of antibiotic use for drug selection, dose, duration, drug-route, and de-escalation. Developing effective surgical prophylaxis regimens is a key strategy in reducing the burden of antibiotic resistance. For treatment of primary spinal infection, the diagnostic work-up is vital in tailoring effective antibiotic therapy. The future of antibiotics in spine surgery will be highly influenced by improving surgical technique and evidence regarding the role of bacteria in the pathogenesis of degenerative spinal pathology.

Conclusions

Incorporating evidence-based guidelines into regular practice will serve to limit the development of resistance while preventing morbidity from spinal infection. Further research should be conducted to provide more evidence for surgical site infection prevention and treatment of spinal infections.

Modic change is associated with increased BMI but not autoimmune diseases in TwinsUK

PURPOSE

Low back pain (LBP) is one of the largest causes of morbidity worldwide. The aetiology of LBP is complex, and many factors contribute to the onset. Bone marrow lesions within the vertebra adjacent to an intervertebral degenerate disc named Modic change (MC) have been suggested as a diagnostic subgroup of LBP. Autoimmune response has been proposed to be one of the causes that promote the development of MC. The aim of the current investigation is to assess prevalence and severity of MC and LBP in participants with an autoimmune disease diagnosis in a well-documented cohort of adult twin volunteers.

METHODS

Multivariate generalized mixed linear models (GLMM) were implemented in order to calculate the association between having an autoimmune disorder and MC prevalence, width and severe and disabling LBP. The model was corrected for family structure as well as for covariates such as age, BMI and smoking.

RESULTS

No association was found between diagnosis of autoimmune disorder and MC. Interestingly, BMI was independently associated with MC width but not to MC prevalence. These results help to shed light on the relationship between MC and autoimmunity as well as the role of BMI in the development of the lesions.

CONCLUSION

This study is the first to examine autoimmune disorders and MC prevalence in a large, population-based female cohort. The study was well powered to detect a small effect. No association was found between having a diagnosis of one or more autoimmune conditions and MC prevalence, width or LBP.

Cytokine Patterns as Predictors of Antibiotic Treatment Effect in Chronic Low Back Pain with Modic Changes: Subgroup Analyses of a Randomized Trial (AIM Study)

Objective

Randomized trials testing the effect of antibiotics for chronic low back pain (LBP) with vertebral bone marrow changes on MRI (Modic changes) report inconsistent results. A proposed explanation is subgroups with low grade discitis where antibiotics are effective, but there is currently no method to identify such subgroups. The objective of the present study was to evaluate whether distinct patterns of serum cytokine levels predict any treatment effect of oral amoxicillin at one-year follow-up in patients with chronic low back pain and Modic changes at the level of a previous lumbar disc herniation.

Design

We used data from an overpowered, randomized, placebo-controlled trial (the AIM study) that tested 100 days of oral 750 mg amoxicillin vs placebo three times daily in hospital outpatients with chronic (>6 months) LBP with pain intensity ≥5 on a 0-10 numerical rating scale and Modic changes type 1 (oedema type) or 2 (fatty type). We measured serum levels of 40 inflammatory cytokines at baseline and analysed six predefined potential predictors of treatment effect based on cytokine patterns in 78 randomized patients; three analyses with recursive partitioning, one based on cluster analysis and two based on principal component analyses. The primary outcome was the Roland-Morris Disability Questionnaire score at one-year follow-up in the intention to treat population. The methodology and overall results of the AIM study were published previously.

Results

The 78 patients were 25-62 years old and 47 (60%) were women. None of the three recursive partitioning analyses resulted in any suggested subgroups. Of all main analyses, the largest effect estimate (mean difference between antibiotic and placebo groups) was seen in a subgroup not predefined as of main interest (Cluster category 3+4; -2.0, 95% CI: -5.2-1.3, RMDQ points; p-value for interaction 0.54).

Conclusion

Patterns of inflammatory serum cytokine levels did not predict treatment effect of amoxicillin in patients with chronic LBP and Modic changes.

Clinical Trial Registration Number

ClinicalTrials.gov (identifier: NCT02323412).

Intradiscal pharmacokinetics of oral antibiotics to treat Chronic Lower Back Pain

Oral coamoxiclav and amoxicillin, for extended dose regimens of up to 100 days, have shown benefit in the treatment of Chronic Lower Back Pain (CLBP) associated with vertebral bone oedema, known as Modic type 1 changes, which may be caused by a bacterial infection, but the magnitude of clinical improvement has been variable. The objectives of this review were to use sparse data from the literature to estimate the exposure of amoxicillin in the intervertebral disc, and to determine whether adequate antimicrobial exposure may have been achieved. Exposure to amoxicillin in herniated disc tissue was approximately 6.5% of the serum concentration. Dosing of oral amoxicillin, Q12h, at doses of up to 1,000 mg is unlikely to lead to effective exposure in disc tissue. Mean exposure to 500 mg or 750 mg of oral Q8h amoxicillin may reach the efficacy target for ~50% of Cutibacterium acnes strains, but not for 90% of C. acnes strains. Mean exposure to 1,000 mg of oral amoxicillin Q8h may reach the target exposure for 90% of strains. Oral amoxicillin CLBP studies may all be underdosed. More than 1400 patients with CLBP and Modic type 1 changes have been exposed to oral amoxicillin for up to 100 days, with no apparent evaluation of systemic or intradiscal pharmacokinetics. Additional clinical evaluations of amoxicillin and alternative antibiotics, their dose regimens, and intradiscal pharmacokinetics are warranted to optimize treatment for this indication. Expertise in antibacterial pharmacokinetics and pharmacodynamics should be included in the design and execution of future studies.

Evaluating Nonoperative Treatment for Low Back Pain in the Presence of Modic Changes: A Systematic Review

OBJECTIVE

The objective of this study was to summarize and assess the current literature evaluating nonoperative treatments for patients with Modic changes (MCs) and low back pain (LBP).

METHODS

A systematic review was conducted in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The PubMed database was searched from its inception until May 1, 2022 for studies evaluating MC and clinical outcomes. Key findings, treatment details, and patient information were extracted from included studies. Study quality was assessed using the Newcastle-Ottawa Scale.

RESULTS

Eighteen studies were included in this review, encompassing a total of 2452 patients, 1713 of whom displayed baseline MC. Seventy-eight percent of studies were high quality. Of included studies, 2 evaluated antibiotics, 5 evaluated steroid injections, 6 evaluated conservative therapies, and 5 evaluated other treatment modalities. Antibiotics and bisphosphonates improved treatment in patients with MC. Patients with MC without disc herniation benefited from conservative therapy, while those with Type I Modic changes and disc herniation experienced poorer improvement. Significant variability exists in reported outcomes following steroid injections.

CONCLUSIONS

Nonoperative therapy may provide patients with MC with significant benefits. Patients may benefit from therapies not traditionally utilized for LBP such as antibiotics or bisphosphonates, but conservative therapy is not recommended for patients with concomitant MC and disc herniation. The large variation in follow-up times and outcome measures contributes to significant heterogeneity in studies and inability to predict long-term patient outcomes. More long-term studies are needed to assess nonoperative treatments for LBP in patients with MC.

Clinical Biomarker of Sterile Inflammation, HMGB1, in Patients with Chronic Non-Specific Low Back Pain: A Pilot Cross-Sectional Study

The present study explores whether the inflammatory biomarker of sterile inflammation, high mobility box 1 (HMGB1), contributes to the inflammatory/nociceptive pathophysiology that characterizes chronic non-specific low back pain (LBP). Patients with chronic LBP (N = 10, >3 pain score on a 11-point Visual Analogue Scale, VAS) and asymptomatic participants (N = 12) provided peripheral blood (PB) samples. The proportion of classical CD14++ monocytes within PB leukocytes was determined by flow cytometry. The plasma and extracellular HMGB1 levels in unstimulated adherent cell (AC) cultures were measured using specific immunoassays. HMGB1 localization in ACs was assessed by immunofluorescent staining. The relative gene expression levels of tumor necrosis factor α (TNFα), interleukin-1 beta (IL-1β) and HMGB1 were determined by quantitative polymerase chain reaction (qRT-PCR) in relation to the pain intensity (11-point VAS scores) in patients with LBP. The extracellular release of HMGB1 in the LBP patient AC cultures was significantly elevated (p = 0.001) and accompanied by its relocation into the cytoplasm from the nuclei. The number of CD14++ monocytes in the patients' PB was significantly (p = 0.03) reduced, while the HMGB1 plasma levels remained comparable to those of the controls. The mRNA levels of TNFα, IL-1β and HMGB1 were overexpressed relative to the controls and those of HMGB1 and IL-1β were correlated with the VAS scores at a significant level (p = 0.01-0.03). The results suggest that HMGB1 may play an important role in the pathophysiology of chronic non-specific LBP.

Immuno-Modulatory Effects of Intervertebral Disc Cells

Low back pain is a highly prevalent, chronic, and costly medical condition predominantly triggered by intervertebral disc degeneration (IDD). IDD is often caused by structural and biochemical changes in intervertebral discs (IVD) that prompt a pathologic shift from an anabolic to catabolic state, affecting extracellular matrix (ECM) production, enzyme generation, cytokine and chemokine production, neurotrophic and angiogenic factor production. The IVD is an immune-privileged organ. However, during degeneration immune cells and inflammatory factors can infiltrate through defects in the cartilage endplate and annulus fibrosus fissures, further accelerating the catabolic environment. Remarkably, though, catabolic ECM disruption also occurs in the absence of immune cell infiltration, largely due to native disc cell production of catabolic enzymes and cytokines. An unbalanced metabolism could be induced by many different factors, including a harsh microenvironment, biomechanical cues, genetics, and infection. The complex, multifactorial nature of IDD brings the challenge of identifying key factors which initiate the degenerative cascade, eventually leading to back pain. These factors are often investigated through methods including animal models, 3D cell culture, bioreactors, and computational models. However, the crosstalk between the IVD, immune system, and shifted metabolism is frequently misconstrued, often with the assumption that the presence of cytokines and chemokines is synonymous to inflammation or an immune response, which is not true for the intact disc. Therefore, this review will tackle immunomodulatory and IVD cell roles in IDD, clarifying the differences between cellular involvements and implications for therapeutic development and assessing models used to explore inflammatory or catabolic IVD environments.

Observation of curative effect on meridian theory-based extracorporeal shock wave therapy for non-specific low back pain: study protocol for a randomized controlled trial

Background

Non-specific low back pain (NLBP) is a major global socioeconomic burden, and the prevalence of NLBP is still on the rise. At present, there is no ideal drug to cure this disease. This may be the reason why patients often use complementary therapies. Among them, extracorporeal shock wave therapy (ESWT) has gradually received more attention and has become the main treatment method for NLBP. The purpose of this study is to provide scientific evidence for the effect and safety of meridian theory-based ESWT on NLBP.

Objective

This study aims to evaluate the effect and safety of meridian theory-based ESWT on NLBP. This study will also provide more high-quality experimental evidence for the clinical application of meridian theory-based ESWT for the treatment of NLBP in future.

Methods

The study design is a single-blind, multi-center, randomized controlled trial. 66 patients with NLBP, aged 18 to 60 years, will be randomly divided into two groups: the experimental group (N = 33), which will receive meridian theory-based ESWT application, and the control group (N = 33) which will receive conventional ESWT treatment. These two applications will be carried out twice a week for two weeks. The primary outcome will be the Visual Analog Scale (VAS), and the secondary outcomes will be Oswestry Disability Index (ODI), Surface Electromyography (sEMG), and Patient Health Questionnaire-15 (PHQ-15). All outcomes will be evaluated at baseline and after the intervention (7 days, 14 days).

Discussion

Results of this trial will contribute to providing rigorous clinical evidence for the efficacy and security of meridian theory-based ESWT for NLBP.

Trial registration: Chinese Clinical Trial Registry, ChiCTR2100051049. Registered on 10 September 2021, http://www.chictr.org.cn/showproj.aspx?proj=46316.

Chronic pain and infection: mechanisms, causes, conditions, treatments, and controversies

Throughout human history, infection has been the leading cause of morbidity and mortality, with pain being one of the cardinal warning signs. However, in a substantial percentage of cases, pain can persist after resolution of acute illness, manifesting as neuropathic, nociplastic (eg, fibromyalgia, irritable bowel syndrome), or nociceptive pain. Mechanisms by which acute infectious pain becomes chronic are variable and can include immunological phenomena (eg, bystander activation, molecular mimicry), direct microbe invasion, central sensitization from physical or psychological triggers, and complications from treatment. Microbes resulting in a high incidence of chronic pain include bacteria such as the Borrelia species and Mycobacterium leprae, as well as viruses such as HIV, SARS-CoV-2 and herpeses. Emerging evidence also supports an infectious cause in a subset of patients with discogenic low back pain and inflammatory bowel disease. Although antimicrobial treatment might have a role in treating chronic pain states that involve active infectious inflammatory processes, their use in chronic pain conditions resulting from autoimmune mechanisms, central sensitization and irrevocable tissue (eg, arthropathy, vasculitis) or nerve injury, are likely to cause more harm than benefit. This review focuses on the relation between infection and chronic pain, with an emphasis on common viral and bacterial causes.

Should Degenerated Intervertebral Discs of Patients with Modic Type 1 Changes Be Treated with Mesenchymal Stem Cells?

Low back pain (LBP) has been among the leading causes of disability for the past 30 years. This highlights the need for improvement in LBP management. Many clinical trials focus on developing treatments against degenerative disc disease (DDD). The multifactorial etiology of DDD and associated risk factors lead to a heterogeneous patient population. It comes as no surprise that the outcomes of clinical trials on intradiscal mesenchymal stem cell (MSC) injections for patients with DDD are inconsistent. Intradiscal MSC injections have demonstrated substantial pain relief and significant disability-related improvements, yet they have failed to regenerate the intervertebral disc (IVD). Increasing evidence suggests that the positive outcomes in clinical trials might be attributed to the immunomodulatory potential of MSCs rather than to their regenerative properties. Therefore, patient stratification for inflammatory DDD phenotypes may (i) better serve the mechanisms of action of MSCs and (ii) increase the treatment effect. Modic type 1 changes—pathologic inflammatory, fibrotic changes in the vertebral bone marrow—are frequently observed adjacent to degenerated IVDs in chronic LBP patients and represent a clinically distinct subpopulation of patients with DDD. This review discusses whether degenerated IVDs of patients with Modic type 1 changes should be treated with an intradiscal MSC injection.

Evidence for infection in intervertebral disc degeneration: a systematic review

Purpose

Back pain is a major problem worldwide and is linked to intervertebral disc degeneration and Modic change. Several studies report growth of bacteria following extraction of degenerate discs at spine surgery. A pathophysiological role for infection in back pain has been proposed.

Method

We conducted a PRISMA systematic review. MEDLINE, PubMed, Scopus and Web of Science were searched with the terms Modic change, intervertebral dis*, bacteria, microb*, and infect*. Date limits of 2001–2021 were set. Human studies investigating the role of bacteria in disc degeneration or Modic change in vertebrae were included.

Results

Thirty-six articles from 34 research investigations relating to bacteria in human degenerate discs were found. Cutibacterium acnes was identified in pathological disc material. A ‘candidate bacterium’ approach has been repeatedly adopted which may have biased results to find species a priori, with disc microbial evidence heavily weighted to find C. acnes.

Conclusion

Evidence to date implicates C. acnes identified through culture, microscopy and sequencing, with some suggestion of diverse bacterial colonisation in the disc. This review found studies which used culture methods and conventional PCR for bacterial detection.

Further agnostic investigation using newer methods should be undertaken.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00586-021-07062-1.

Chronic low back pain, Modic changes and low-grade virulent infection: efficacy of antibiotic treatment

Chronic low back pain (CLBP) has consistently been associated with the longest number of years lived with a disability in global studies, while commonly used treatments for CLBP are largely ineffective. In 2013 a randomized, double-blind, controlled study demonstrated significant improvements in CLBP patients demonstrating Modic changes type 1 on their MRI scans and undergoing long-term oral antibiotic treatment (100 days). Much of the ensuing debate has focused on whether this was a true infection or contamination. Newer and more advanced technologies clearly point to an ongoing low-grade infection. We have reviewed all of the clinical trials published in the recent past and conclude that there is compelling evidence for the effect of long-term oral antibiotic treatment for this patient group.