Disc inflammation and Modic changes show an interaction effect on recovery after surgery for lumbar disc herniation

From Modic to Disc Endplate Bone Marrow Complex - The Natural Course and Clinical Implication of Vertebral Endplate Changes

STUDY DESIGN

Review article.

OBJECTIVES

A review of literature on the epidemiology, natural course, pathobiology and clinical implications of vertebral endplate changes.

METHODS

A literature search was performed using the Cochrane Database of Systematic Reviews, EMBASE, and PubMed. Studies published over the last 10 years were analysed. The searches were performed using Medical Subject Headings terms, and the subheadings used were "Vertebral endplate changes", "Modic changes", "Disc Endplate Bone Marrow complex".

RESULTS

The disc, endplate (EP), and bone marrow region of the spine constitute a unified morphological and functional unit, with isolated degeneration of any one structure being uncommon. Disc degeneration causes endplate defects, which result in direct communication and a constant cross-talk between the disc and the vertebral body. This may result in a persistent inflammatory state of the vertebral bone marrow, serving as a major pain generator. This review article focuses on vertebral endplate changes and how the current understanding has progressed from the Modic classification to the Disc Endplate Bone Marrow complex classification. It provides a clear portrayal of the natural course of these alterations and their clinical implications in low back pain.

CONCLUSIONS

In light of the heightened interest and current prominence of vertebral endplate changes within the spine community, we must progress beyond the Modic changes to achieve a comprehensive understanding. The DEBM complex classification will play a major part in disc degeneration research and clinical care, representing a considerable advancement in our understanding of the vertebral endplate changes over the classical Modic changes.

Nomogram Development and Validation for Predicting Postoperative Recurrent Lumbar Disc Herniation Based on Paraspinal Muscle Parameters

Purpose

Previous studies highlight paraspinal muscles' significance in spinal stability. This study aims to assess paraspinal muscle predictiveness for postoperative recurrent lumbar disc herniation (PRLDH) after lumbar disc herniation patients undergo percutaneous endoscopic transforaminal discectomy (PETD).

Patients and Methods

Retrospectively collected data from 232 patients undergoing PETD treatment at our institution between January 2020 and January 2023, randomly allocated into training (60%) and validation (40%) groups. Utilizing Lasso regression and multivariable logistic regression, independent risk factors were identified in the training set to construct a Nomogram model. Internal validation employed Enhanced Bootstrap, with Area Under the ROC Curve (AUC) assessing accuracy. Calibration was evaluated through calibration curves and the Hosmer-Lemeshow goodness-of-fit test. Decision curve analysis (DCA) and clinical impact curve (CIC) were employed for clinical utility analysis.

Results

Diabetes, Modic changes, and ipsilesional multifidus muscle skeletal muscle index (SMI) were independent predictive factors for PRLDH following PETD (P<0.05). Developed Nomogram model based on selected predictors, uploaded to a web page. AUC for training: 0.921 (95% CI 0.872-0.970), validation: 0.900 (95% CI 0.828-0.972), respectively. The Hosmer-Lemeshow test yielded χ 2=5.638/6.259, P=0.688/0.618, and calibration curves exhibited good fit between observed and predicted values. DCA and CIC demonstrate clinical net benefit for both models at risk thresholds of 0.02-1.00 and 0.02-0.80.

Conclusion

The Nomogram predictive model developed based on paraspinal muscle parameters in this study demonstrates excellent predictive capability and aids in personalized risk assessment for PRLDH following PETD.

No evidence of association between either Modic change or disc degeneration and five circulating inflammatory proteins

Introduction

Intervertebral disc degeneration and Modic change are the main spinal structural changes associated with chronic low back pain (LBP). Both conditions are thought to manifest local inflammation and if inflammatory proteins translocate to the blood circulation could be detected systemically. The work here assesses whether the presence of disc degeneration is associated with detectable blood level changes of five inflammatory markers and whether chronic LBP is associated with these changes.

Materials and Methods

Two hundred and forty TwinsUK cohort participants with both MRI disc degeneration grade and Modic change extent, and IL-6, IL-8, IL-8 TNF, and CX3CL1 protein blood concentration measurements were included in this work. Linear mixed effects models were used to test the association of blood cytokine concentration with disc degeneration score and Modic change volumetric score. Association of chronic LBP status from questionnaires with disc degeneration, Modic change, and cytokine blood concentration was also tested.

Results

No statistically significant association between disc degeneration or Modic change with cytokine blood concentration was found. Instead, regression analysis pointed strong association between cytokine blood concentration with body mass index for IL-6 and with age for IL-6 and TNF. Mild association was found between IL-8 blood concentration and body mass index. Additionally, LBP status was associated with Modic change volumetric score but not associated with any cytokine concentration.

Conclusions

We found no evidence that Modic change and disc degeneration are able to produce changes in tested blood cytokine concentration. However, age and body mass index have strong influence on cytokine concentration and both are associated with the conditions studied which may confound associations found in the literature. It is then unlikely that cytokines produced in the disc or vertebral bone marrow induce chronic LBP.

Clinical effects and biological mechanisms of exercise on lumbar disc herniation

Lumbar Disc Herniation (LDH) is a syndrome in which lumbar disc degeneration, rupture of the annulus fibrosus, and herniation of the nucleus pulposus irritate and compress the nerve roots and cauda equina, resulting in the main manifestations of lumbar pain and/or lower extremity pain. There is evidence in various clinical areas that exercise is effective in treating LDH, and exercise intervention for more than 2 weeks reduces disease activity in LDH. However, the mechanism of exercise's action in reducing disease activity in LDH is unclear. In this article, we first summarize and highlight the effectiveness of exercise in treating LDH and provide guideline recommendations regarding exercise type, intensity, frequency, and duration. Then, we integrate the existing evidence and propose biological mechanisms for the potential effects of exercise on neuromechanical compression, inflammatory chemical stimuli, and autoimmune responses from the perspective of LDH pathogenesis as an entry point. However, a large body of evidence was obtained from non-LDH populations. Future research needs to investigate further the proposed biological mechanisms of exercise in reducing disease activity in LDH populations. This knowledge will contribute to the basic science and strengthen the scientific basis for prescribing exercise therapy for the routine clinical treatment of LDH.

Asymmetric distribution of Modic changes in patients with lumbar disc herniation

PURPOSE

This study aims to report a new distribution pattern of Modic changes (MCs) in patients with lumbar disc herniation (LDH) and investigate the prevalence, correlative factors and clinical outcomes of asymmetric Modic changes (AMCs).

METHODS

The study population consisted of 289 Chinese Han patients who were diagnosed with LDH and single-segment MCs from January 2017 to December 2019. Demographic, clinical and imagological information was collected. Lumbar MRI was performed to assess MCs and intervertebral discs. The visual analogue score (VAS) and Oswestry disability index (ODI) were evaluated in patients undergoing surgery preoperatively and at the final follow-up. Correlative factors contributing to AMCs were analysed by multivariate logistic regression.

RESULTS

The study population included 197 patients with AMCs and 92 patients with symmetric Modic changes (SMCs). The incidence of leg pain (P < 0.001) and surgical treatment (P = 0.027) in the AMC group was higher than that in the SMC group. The VAS of low back pain was lower (P = 0.048), and the VAS of leg pain was higher (P = 0.036) in the AMC group than in the SMC group preoperatively. Multivariate logistic regression analysis revealed that leg pain (OR = 2.169, 95% CI = 1.218 ~ 3.864) and asymmetric LDH (OR = 7.342, 95% CI = 4.170 ~ 12.926) were independently associated with AMCs. The receiver operating characteristic curve showed an AUC of 0.765 (P < 0.001).

CONCLUSION

AMCs were a more common phenomenon than SMCs in this study. The asymmetric and symmetric distribution of MCs was closely related to LDH position. AMCs were related to leg pain and higher pain levels. Surgery can achieve satisfactory clinical improvement for asymmetric and symmetric MCs.

Correlations of Disc Tissue Pathological Changes With Pfirrmann Grade in Patients With Disc Herniation Treated With Microdiscectomy

BACKGROUND

To reveal whether pathological disc changes (vascularization, inflammation, disc aging and senescence as assessed with immunohistopathological CD34, CD68, brachyury and P53 staining densities respectively) are associated with the extent of disease (Pfirrmann grade) and lumbar radicular pain in patients with lumbar disc herniation. We selectively included a homogenous group of 32 patients (16 males and 16 females) with single-level sequestered discs who had disease stages between Pfirrmann grades I to IV and excluded patients with the complete collapse of the disc space to determine histopathological correlations of the disease more precisely.

MATERIALS AND METHODS

Pathological assessments were performed on surgically excised disc specimens stored in a -80°C refrigerator. Preoperative and postoperative pain intensities were determined with visual analog scales (VASs). Pfirrmann disc degeneration grades were determined on routine T2-weighted magnetic resonance imaging (MRI).

RESULTS

Stainings were especially observed with CD34 and CD68, which positively correlated with each other and Pfirrmann grading but not with VAS scores or patients' age. Weak nuclear staining with brachyury was observed in 50% of patients and did not correlate with disease features. Focal weak staining with P53 was only seen in the disc specimen of two patients.

CONCLUSIONS

In the pathogenesis of disc disease, inflammation may trigger angiogenesis. The subsequent aberrant increase of oxygen perfusion in the disc cartilage may cause further damage, as the disc tissue is adapted to hypoxia. This vicious cycle of inflammation and angiogenesis may be a future innovative therapeutic target for chronic degenerative disc disease.

Exploring macrophage differentiation and its relation to Modic changes in human herniated disc tissue

Introduction

Cervical- and lumbosacral radiculopathy symptoms due to disc herniation are likely to be influenced by macrophage infiltration of the herniated disc. Vertebral endplate changes are hypothesized to, at least partially, correlate to the inflammatory condition of the disc and its environment.

Research question

The present study aims to evaluate several immunohistochemical M1-and M2-markers for their suitability to discern pro-inflammatory M1-and anti-inflammatory M2 macrophage differentiation patterns in herniated intervertebral disc tissue. In addition, their associations with Modic changes (MC) of the vertebral endplates will be evaluated.

Materials and methods

Herniated disc samples were collected from 45 patients undergoing surgery for cervical- or lumbosacral radiculopathy. Samples were processed for immunohistochemistry and stained for the presence of macrophages: CD68 (macrophage marker), CD40 (M1), iNOS (M1), CD192 (M1), CD163 (M2), Arg1 (M2) and CD209 (M2). T-cells (CD3) and neutrophil (CD15) expressions were studied additionally.

Results

CD68 positive cells were present with a median density of 50/cm², M2 markers CD163 and CD209 were expressed most dominantly, followed by M1 marker CD192. Other M1/M2 markers, T-cell and neutrophil expression was limited. Lumbar samples showed higher expression of iNOS and Arg1 compared to cervical samples. Presence of Modic changes was associated with higher levels of CD68⁺ cells (p ​= ​0.046), but no significant differences in M1/M2 markers were found.

Discussion and conclusion

For studying M1 macrophages, CD192 is the most suitable marker due to its high expression; whereas for M2 macrophages, this is CD163 due to its high expression and selectivity. Further, the relatively high expression of M2 markers indicates predominance of anti-inflammatory over pro-inflammatory macrophages in symptomatic lumbar and cervical disc herniations. No associations between M1/M2 markers and MC were seen in this limited number of samples. In order to further explore the role of macrophage differentiation and its relation with MC in radiculopathy, a large prospective trial with elaborate clinical follow-up is required.

Characteristics and mechanisms of resorption in lumbar disc herniation

Lumbar disc herniation (LDH) can be spontaneously absorbed without surgical treatment. However, the pathogenesis and physiological indications for predicting protrusion reabsorption are still unclear, which prevents clinicians from preferentially choosing conservative treatment options for LDH patients with reabsorption effects. The purpose of this review was to summarize previous reports on LDH reabsorption and to discuss the clinical and imaging features that favor natural absorption. We highlighted the biological mechanisms involved in the phenomenon of LDH reabsorption, including macrophage infiltration, inflammatory responses, matrix remodeling, and neovascularization. In addition, we summarized and discussed potential clinical treatments for promoting reabsorption. Current evidence suggests that macrophage regulation of inflammatory mediators, matrix metalloproteinases, and specific cytokines in intervertebral disc is essential for the spontaneous reabsorption of LDH.

Evaluating the Impact of Modic Changes on Operative Treatment in the Cervical and Lumbar Spine: A Systematic Review and Meta-Analysis

Modic changes (MCs) are believed to be potential pain generators in the lumbar and cervical spine, but it is currently unclear if their presence affects postsurgical outcomes. We performed a systematic review in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. All studies evaluating cervical or lumbar spine postsurgical outcomes in patients with documented preoperative MCs were included. A total of 29 studies and 6013 patients with 2688 of those patients having preoperative MCs were included. Eight included studies evaluated cervical spine surgery, eleven evaluated lumbar discectomies, nine studied lumbar fusion surgery, and three assessed lumbar disc replacements. The presence of cervical MCs did not impact the clinical outcomes in the cervical spine procedures. Moreover, most studies found that MCs did not significantly impact the clinical outcomes following lumbar fusion, lumbar discectomy, or lumbar disc replacement. A meta-analysis of the relevant data found no significant association between MCs and VAS back pain or ODI following lumbar discectomy. Similarly, there was no association between MCs and JOA or neck pain following ACDF procedures. Patients with MC experienced statistically significant improvements following lumbar or cervical spine surgery. The postoperative improvements were similar to patients without MCs in the cervical and lumbar spine.

The Thermosensitive Injectable Celecoxib-Loaded Chitosan Hydrogel for Repairing Postoperative Intervertebral Disc Defect

Percutaneous endoscopic lumbar discectomy has been widely used in clinical practice for lumbar spine diseases. But the postoperative disc re-herniation and inflammation are the main reason for pain recurrence after surgery. The postoperative local defect of the intervertebral disc will lead to the instability of the spine, further aggravating the process of intervertebral disc degeneration. In this work, we successfully synthesized the thermosensitive injectable celecoxib-loaded chitosan hydrogel and investigated its material properties, repair effect, biocompatibility, and histocompatibility in in vitro and in vivo study. In vitro and in vivo, the hydrogel has low toxicity, biodegradability, and good biocompatibility. In an animal experiment, this composite hydrogel can effectively fill local tissue defects to maintain the stability of the spine and delay the process of intervertebral disc degeneration after surgery. These results indicated that this composite hydrogel will be a promising way to treat postoperative intervertebral disc disease in future clinical applications.

Medical Data Analysis of Lumbar Disc Herniation Patients after Traditional Chinese Medicine Rehabilitation Intervention Lumbar Function Recovery

In order to study the efficacy of TCM rehabilitation for lumbar disc herniation, it is suggested to compare the effects of hot compress, ordinary sandbag, or hot compress with traditional Chinese medicine. A total of 79 patients with Qi stagnation and blood stasis syndrome in a traditional Chinese medicine hospital who met the diagnostic criteria of LDH and the syndrome classification in the diagnostic efficacy criteria of traditional Chinese medicine were selected. The subjects were randomly divided into groups A, B, and C: group A (26 cases) was the sandbag hot compress dry pregroup and received the simple sandbag hot compress scheme; group B (26 cases) was a simple traditional Chinese medicine hot compress intervention group, which received traditional Chinese medicine hot compress scheme; group C (27 cases) was the intervention group of traditional Chinese medicine sandbag combined with hot compress and received the scheme of traditional Chinese medicine sandbag combined with hot compress. In addition to the different hot compress media used, other aspects remained the same among the three groups. The treatment time of each hot compress was 40 min, twice a day for 2 weeks. A total of 14 cases fell out during the intervention process, and 65 subjects completed the intervention process. The experiment showed that there was no significant difference among the three groups (P > 0.05). The test results were confirmed.

Heterogeneous macrophages contribute to the pathology of disc herniation induced radiculopathy

BACKGROUND CONTEXT

Macrophages play important roles in the progression of intervertebral disc herniation and radiculopathy.

PURPOSE

To better understand the roles of macrophages in this process, we developed a new mouse model that mimics human radiculopathy.

STUDY DESIGN/SETTING

A preclinical randomized animal study.

METHODS

Three types of surgeries were performed in randomly assigned Balb/c mice. These were spinal nerve exposure, traditional anterior disc puncture, and lateral disc puncture with nerve exposure (n=16/group). For the nerve exposure group, the left L5 spinal nerve was exposed without disc injury. For the traditional anterior puncture, L5/6 disc was punctured by an anterior approach as previously established. For lateral puncture with nerve exposure, the left L5 spinal nerve was exposed by removing the psoas major muscle fibers, and the L5/6 disc was punctured laterally on the left side with a 30G needle, allowing the nucleus to protrude toward the L5 spinal nerve. Mechanical hyperalgesia (pain sensitivity) of hind paws was assessed with electronic von Frey assay on alternative day for up to 2 weeks. MRI, histology, and immunostaining were performed to confirm disc herniation and inflammation.

RESULTS

Ipsilateral pain in the lateral puncture with nerve exposure group was significantly greater than the other groups. Pro-inflammatory cytokines IL-1β and IL-6 were markedly elevated at the hernia sites of both puncture groups and the spinal nerve of lateral puncture with never exposure group on postoperative day 7. Heterogeneous populations of macrophages were detected in the infiltration tissue of this mouse model and in tissue from patients undergone discectomy.

CONCLUSIONS

We have established a new mouse model that mimics human radiculopathy and demonstrated that a mixed phenotype of macrophages contribute to the pathogenesis of acute discogenic radiculopathy.

CLINICAL SIGNIFICANCE

This study provides a clinically relevant in vivo animal model to elucidate complex interactions of disc herniation and radicular pain, which may present opportunities for the development of macrophage-anchored therapeutics to manage radiculopathy.

Low-Dose Collagenase Chemonucleolysis Combined with Radiofrequency in the Treatment of Lumbar Disc Herniation: A 10-Year Retrospective Study

Objective

This study explored the 10-year efficacy, safety, and prognostic factors of low-dose collagenase chemonucleolysis (CCNL) combined with radiofrequency (RF) in the treatment of lumbar disc herniation (LDH).

Methods

The data of 167 LDH patients were collected. Modified MacNab criteria, Numerical Rating Scale (NRS), and Japanese Orthopedic Association (JOA) scores were, respectively, used to evaluate patients' excellent and good rates, pain degree, and nerve function. The preoperative and 10-year postoperative patients' pain, numbness, and muscle weakness were compared. Patients' complications in perioperative period, recurrent/reappeared LDH, and reoperations were recorded. Finally, the independent risk factors affecting the long-time efficacy were assessed.

Results

A total of 126 patients were included. The patients' excellent and good rates were 86.51%–92.86% with no significant difference (P > 0.05). Postoperative NRS and JOA scores significantly improved (P < 0.01), most obvious within 6 months postoperatively. At 10 years postoperatively, 65.08%, 83.95%, and 93.02% of patients' pain, numbness, and muscle weakness were completely relieved (P < 0.05). Perioperative complications occurred in three patients with the rate of 2.38%. Recurrent/reappeared LDH patients were 11 with the ratio of 8.73%; nine of them underwent reoperations with the rate of 7.14%. And patients' probability of fair and poor efficacy at 10 years postoperatively with the course of disease >12 months and the responsibility disc ≥2 were, respectively, 6.005 and 4.227 times that of patients with the course of disease ≤12 months and the responsibility disc = 1 (P < 0.05).

Conclusion

The combined treatment is effective and safe in the long term. A course of disease >12 months and responsibility disc ≥2 independently reduce efficacy, and a course of disease >12 months has a more significant impact.

Modic changes are associated with activation of intense inflammatory and host defense response pathways - molecular insights from proteomic analysis of human intervertebral discs

BACKGROUND CONTEXT

Patients with modic changes (MC) form a distinct clinical subset with reports of higher intensity of pain, poor clinical and surgical outcomes and higher incidence of recurrence. MC also is an independent risk factor for increased post-operative surgical site infection.

PURPOSE

This study aimed to investigate the biological changes at molecular level, in discs with MCs. We also aim to identify biological biomarkers and potential targets for molecular therapy.

STUDY DESIGN

Experimental analysis MATERIALS AND METHODS: Nucleus pulposus (NP) from 24 patients undergoing microdiscectomy for disc herniation [14 discs with MC and 10 without modic changes (NMC)] were procured. The overall expression of proteins, biological processes, protein-protein and metabolite interactions were analysed and compared. Host defense response proteins (HDRPs) and immunological pathways activated in patients with MC were documented and analysed.

RESULTS

Label-free proteomic approach with stringent filters revealed a total of 208 proteins in MC and 193 in NMC groups. 45 proteins were specific to MC; 30 to NMC and 163 common to both. Downregulated proteins in MC belonged to components of extracellular matrix such as collagens (COL- 6A1, 6A2, 6A3, 11A1, 12A1, and 20A1), and proteoglycans (versican (VCAN), and biglycan (BGN)). Inflammatory molecules [plasminogen (PLG), angiogenin (ANG), fibroblast growth factor-binding protein 2 (FGFBP2), tetranectin (CLEC3B), cartilage acidic protein 1(CRTAC1), kininogen (KNG-1), chitinase-3-like protein 2 (CHI3L2), and ferritin (FTL) were expressed only in the MC group. The significantly altered pathways in MC included Fc Fragment of IgG Receptor IIIa (FCGR3A)-mediated phagocytosis, regulation of Toll-like receptors (TLR) by endogenous ligand, neutrophil and platelet degranulation. 50 HDRPs were identified in the study, 14 of which were specific to MC and included acute phase reactants, antimicrobial peptides, complement cascade proteins, inflammatory molecule and stress response proteins. Metabolite-protein interaction analysis revealed a significant interaction between 19 proteins, specifically involving ubiquitin mediating proteasome degradative pathway and an association with the metabolite-glutamic acid in the MC group. Accumulation of glutamic acid in MC discs was confirmed by quantitative amino acid analysis using High-performance liquid chromatography.

CONCLUSION

Our study confirms that MC represents an intense inflammatory status and activation of host defense response and immunological pathways. Downstream effects leading to ubiquitin mediated proteasomal degradation of ECM proteins and the resulting metabolites such as glutamic acid could cause excessive pain and needs further investigation.

CLINICAL SIGNIFICANCE

We have documented the expression of inflammatory molecules, immune mechanisms and host defense response proteins which throw molecular insights into the pathological mechanisms of MC. Further, ubiquitin mediated proteasomal degradation and accumulation of glutamate in discs with MC might serve as targets for molecular therapy.

Influence of endplate avulsion and Modic changes on the inflammation profile of herniated discs: a proteomic and bioinformatic approach

PURPOSE

The aim of this observational radiographic and proteomic study is to explore the influence of both Modic change (MC) and endplate avulsion (EPA) on the inflammation profile of herniated discs using a proteomic and bioinformatics approach.

METHODS

Fifteen nucleus pulposus (NP) harvested from surgery underwent LC-MS/MC analysis, the proteome was subsequently scanned for inflammatory pathways using a bioinformatics approach. All proteins that were identified in inflammatory pathways and Gene Ontology and present in > 7 samples were integrated in a multiple regression analysis with MC and EPA as predictors. Significant proteins were imputed in an interaction and pathway analysis.

RESULTS

Compared to annulus fibrosus tear (AFT), six proteins were significantly altered in EPA: catalase, Fibrinogen beta chain, protein disulfide-isomerase, pigment epithelium-derived factor, osteoprotegerin and lower expression of antithrombin-III, all of which corresponded to an upregulation of pathways involved in coagulation and detoxification of reactive oxygen species (ROS). Moreover, the presence of MC resulted in a significant alteration of nine proteins compared to patients without MC. Patients with MC showed a significantly higher expression of clusterin and lumican, and lower expression of catalase, complement factor B, Fibrinogen beta chain, protein disulfide-isomerase, periostin, Alpha-1-antitrypsin and pigment epithelium-derived factor. Together these altered protein expressions resulted in a downregulation of pathways involved in detoxification of ROS, complement system and immune system. Results were verified by Immunohistochemistry with CD68 cell counts.

CONCLUSION

Both EPA and MC status significantly influence disc inflammation. The beneficial inflammatory signature of EPA illustrates that endplate pathology does not necessarily have to worsen the outcome, but the pathological inflammatory state is dependent on the presence of MC.

Study protocol: effect of infection, Modic and inflammation on clinical outcomes in surgery for radiculopathy (EIMICOR)

BACKGROUND

Evidence indicates that inflammatory processes are involved in radicular pain as well as in resorption of herniated disc tissue. Furthermore there are indications that the presence of vertebral end plate pathology (Modic changes; MC) is associated with a negative effect on inflammation. It is hypothesized that in patients with MC, the (possibly bacterial induced) inflammation will be accompanied by pro inflammatory cytokines that worsen the outcome, and that in patients without MC, the inflammation is accompanied by cytokines that induce a resorption process to accelerate recovery.

METHODS

This prospective cohort study will include 160 lumbar and 160 cervical patients (total of 320), which are scheduled for surgery for either a lumbar or cervical herniated disc with ages between 18 and 75. The main and interaction effects of local bacterial infection (culture), inflammatory cells in disc material (immunohistology), MC (MRI), and blood biomarkers indicating inflammation or infection (blood sample evaluation) will be evaluated. Clinical parameters to be evaluated are leg pain on the 11 point NRS pain scale, Oswestry (lumbar spine) or Neck (cervical spine) Disability Index, Global Perceived Recovery, Womac Questionnaire, and medication status, at baseline, and after 6, 16, 26 and 52 weeks.

DISCUSSION

Gaining insight in the aetiology of pain and discomfort in radiculopathy caused by a herniated disc could lead to more effective management of patients. If the type of inflammatory cells shows to be of major influence on the rate of recovery, new immunomodulating treatment strategies can be developed to decrease the duration and intensity of symptoms. Moreover, identifying a beneficial inflammatory response in the disc through a biomarker in blood could lead to early identification of patients whose herniations will resorb spontaneously versus those that require surgery.

TRIAL REGISTRATION

prospectively enrolled at trialregister.nl, ID: NL8464 .

Cartilaginous endplate avulsion is associated with modic changes and endplate defects, and residual back and leg pain following lumbar discectomy

OBJECTIVE

While cartilaginous endplate (CEP) avulsion is a common finding in discectomy due to lumbar disc herniation, its roles in residual back and leg pain, associations with Modic changes (MCs) and endplate defects (EPD) remain unknown.

DESIGN

Patients with a single-level lumbar disc herniation who underwent endoscopic discectomy were studied. On MR images, the adjacent endplates of the herniated disc were assessed for MCs and EPD. The presence of CEP avulsion was examined under endoscopic and visualized inspection. Back and leg pain were evaluated by a numeric rating scale (NRS) and the Oswestry Disability Index. Associations of CEP avulsion with adjacent MCs, EPD, and residual back and leg pain were examined. In addition, histological features of avulsed CEP were determined using gross staining and immunohistochemical methods.

RESULTS

A total of 386 patients were included. CEP avulsion was found in 166 (43%) patients, and adjacent MCs and EPD were observed in 117 (30.3%) and 139 (36%) patients. The presence of CEP avulsion was associated with greater age, adjacent MCs (OR = 2.60, 95%CI [1.61-4.19]) and EPD (OR = 1.63, 95%CI [1.03-2.57]). Among the 187 patients with ≥2 years follow-up, CEP avulsion was associated with residual back pain (OR = 2.49, 95%CI [1.29-4.82]) and leg pain (OR = 2.25, 95%CI [1.04-4.84]). Histologically, the avulsed CEP was characterized by multiple defects, apparent inflammation, and nucleus invasion, as well as the upregulation of IL-1β, caspase-1, and NLRP3 inflammasome.

CONCLUSION

CEP avulsion was associated with MCs, EPD, and residual back and leg pain after discectomy, which may be attributed to NLRP3 inflammasome related inflammations.

Epigenetic modulation of macrophage polarization prevents lumbar disc degeneration

Inflammation plays an essential role in the development of lumbar disc degeneration (LDD), although the exact effects of macrophage subtypes on LDD remain unclear. Based on previous studies, we hypothesized that M2-polarization of local macrophages and simultaneous suppression of their production of fibrotic transforming growth factor beta 1 (TGFβ1) could inhibit progression of LDD. Thus, we applied an orthotopic injection of adeno-associated virus (AAV) carrying shRNA for DNA Methyltransferase 1 (DNMT1) and/or shRNA for TGFβ1 under a macrophage-specific CD68 promoter to specifically target local macrophages in a mouse model for LDD. We found that shDNMT1 significantly reduced levels of the pro-inflammatory cytokines TNFα, IL-1β and IL-6, significantly increased levels of the anti-inflammatory cytokines IL-4 and IL-10, significantly increased M2 macrophage polarization, significantly reduced cell apoptosis in the disc degeneration zone and significantly reduced LDD-associated pain. The anti-apoptotic and anti-pain effects were further strengthened by co-application of shTGFβ1. Together, these data suggest that M2 polarization of macrophages induced by both epigenetic modulation and suppressed production and release of TGFβ1 from polarized M2 macrophages, may have a demonstrable therapeutic effect on LDD.

Modic changes - An evidence-based, narrative review on its patho-physiology, clinical significance and role in chronic low back pain

OBJECTIVE

Lumbar degenerative spinal ailments are the most important causes for chronic low back pain. Modic changes (MC) are vertebral bone marrow signal intensity changes seen on MRI, commonly in association with degenerative disc disease (DDD). Despite being widely studied, majority of issues concerning MC are still controversial. The current narrative, evidence-based review comprehensively discusses the various aspects related to MC.

LITERATURE SEARCH

An elaborate search was made using keywords "Modic changes", "lumbar Modic changes", "Modic changes in lumbar spine", and "vertebral Endplate Spinal Changes", on pubmed and google (scholar.google.com) databases on the 3rd of March 2020. We identified crucial questions regarding Modic changes and included relevant articles pertaining to these topics for this narrative review.

RESULTS

The initial search using the keywords "Modic changes", "lumbar Modic changes", "Modic changes in lumbar spine", and "vertebral Endplate Spinal Changes" on pubmed yielded a total of 568, 412, 394 and 216 articles on "pubmed" database, respectively. A similar search using the aforementioned keywords yielded a total of 3650, 3548, 3726 and 21570 articles on "google scholar" database. The initial screening involved exclusion of duplicate articles, articles unrelated to MC, animal or other non-clinical studies, and articles in non-English literature based on abstracts or the titles of articles. This initial screening resulted in the identification of 405 articles. Full manuscripts were obtained for all these selected articles and thoroughly scrutinised at the second stage of article selection. All articles not concerning Modic changes, not pertaining to concerned questions, articles concerning other degenerative phenomena, articles discussing cervical or thoracic MC, case reports or animal studies, articles in non-English language and duplicate articles were excluded. Review articles, randomised controlled trials and level 1 studies were given preference. Overall, 69 articles were included in this review.

CONCLUSION

Modic change (MC) is a dynamic phenomenon and its true etiology is still not definitely known. Disc/end plate injury, occult discitis and autoimmune reactions seem to trigger an inflammatory cascade, which leads to their development. Male sex, older age, diabetes mellitus, genetic factors, smoking, obesity, spinal deformities, higher occupational loads and DDD are known risk factors. There is no conclusive evidence on the causative role of MC in chronic low back pain (LBP) or any influence on the long term outcome in patients with LBP or lumbar disc herniations (LDH). Patients with MC have been reported to have less satisfactory outcome following conservative treatment or discectomy, although the evidence is still unclear.