Pathophysiology, diagnosis, and treatment of discogenic low back pain

Proteomic profiling of human plasma and intervertebral disc tissue reveals matrisomal, but not plasma, biomarkers of disc degeneration

BACKGROUND

Intervertebral disc (IVD) degeneration is a common cause of low back pain, and the most symptomatic patients with neural compression need surgical intervention to relieve symptoms. Current techniques used to diagnose IVD degeneration, such as magnetic resonance imaging (MRI), do not detect changes in the tissue extracellular matrix (ECM) as degeneration progresses. Improved techniques, such as a combination of tissue and blood biomarkers, are needed to monitor the progression of IVD degeneration for more effective treatment plans.

METHODS

To identify tissue and blood biomarkers associated with degeneration progression, we histologically graded 35 adult human degenerate IVD tissues and matched plasma from the individuals into two groups: mild degenerate and severe degenerate. Mass spectrometry was utilised to characterise proteomic differences in tissue and plasma between the two groups. Top differentially distributed proteins were further validated using immunohistochemistry and qRT-PCR. Additionally, correlational analyses were conducted to define similarities and differences between tissue and plasma protein changes in individuals with mild and severe IVD degeneration.

RESULTS

Our data revealed that the abundance of 31 proteins was significantly increased in severe degenerated IVD tissues compared to mild. Functional analyses showed that more than 40% of these proteins were matrisome-related, indicating differences in ECM protein composition between severe and mild degenerate IVD tissues. We confirmed adipocyte enhancer-binding protein 1 (AEBP1) as one of the most significantly enriched core matrisome genes and proteins as degeneration progressed. Compared to others, AEBP1 protein levels best distinguished between mild and severe degenerated IVD tissues with an area under the curve score of 0.768 (95% CI: 0.60-0.93). However, we found that protein changes from associated plasma exhibited a weak relationship with histological grading and AEBP1 tissue levels. Given that systemic plasma changes are complex, a larger sample cohort may be required to identify patterns in blood relating to IVD degeneration progression.

CONCLUSIONS

In this study, we have identified AEBP1 as a tissue marker for monitoring the severity of disc degeneration in humans. Further work to link alterations in tissue AEBP1 levels to changes in blood-related proteins will be beneficial for detailed monitoring of IVD degeneration thereby enabling more personalised treatment approaches.

Ferristatin II protects nucleus pulposus against degeneration through inhibiting ferroptosis and activating HIF-1α pathway mediated mitophagy

BACKGROUND

Nucleus pulposus (NP) degeneration represents a significant contributing factor in the pathogenesis of intervertebral disc (IVD) degeneration (IVDD), and is a key underlying mechanism in several lumbar spine pathologies. Nevertheless, the precise mechanisms that govern NP degeneration remain unclear. A significant contributing factor to IVDD has been identified as ferroptosis. Nevertheless, its function in the degeneration of NP remains uncertain. The transferrin receptor inhibitor Ferristatin II (Fer-II) has been demonstrated to possess neuroprotective properties, which are conferred by its ability to suppress ferroptosis. It is therefore crucial to investigate the mechanisms by which Fer-II exerts its protective effects against NP degradation.

METHODS

In order to investigate the protective effects of Fer-II, an IVDD rat model was developed by puncturing the rat tail in vivo. Human NP cells extracted with the aid of tert-butyl hydroperoxide (TBHP) and ferric ammonium citrate (FAC) interventions mimic the IVDD pathological environment in vitro.

RESULTS

The present study demonstrates that Fer-II can delay nucleus pulposus degeneration and IVDD by inhibiting ferroptosis. This conclusion was reached through epidemiological studies and in vitro and in vivo experiments. Furthermore, Fer-II was observed to alleviate oxidative stress-induced NP cell degeneration by activating the HIF-1α pathway, enhancing mitophagy, suppressing NP cell ferroptosis.

CONCLUSIONS

The findings of our study indicate that Fer-II has the potential to safeguard nucleus pulposus cells from degeneration by triggering HIF-1α-mediated mitophagy. The potential of Fer-II as a promising alternative therapeutic option for the management of IVDD is worthy of further investigation.

Human molecular mechanisms of discogenic low back pain: A scoping review

The limited understanding of the mechanisms underlying human discogenic low back pain (DLBP) has hampered the development of effective treatments. While there is much research on disc degeneration, the association between degeneration and pain is weak. Therefore, there is an urgent need to identify pain-inducing molecular mechanism to facilitate the development of mechanism-specific therapeutics. This scoping review aims to determine the current knowledge of molecular mechanisms associated with human DLBP. A systematic search on CENTRAL, CINAHL, Citation searching, ClinicalTrials.gov, Embase, Google Scholar, MEDLINE, PsycINFO, PubMed, Scopus, Web of Science, and World Health Organization was performed. Studies with human DLBP as diagnosed by discography or imaging that analyzed human disc tissues and reported pain-related outcomes were included, and those on predominant radicular pain were excluded. The search returned 6012 studies. Most studies did not collect pain-related outcomes. Those that included pain assessment relied on self-report of pain intensity and disability. Six studies qualified for data extraction and synthesis. The main molecular mechanisms associated with DLBP were the expressions of nociceptive neuropeptides and cytokines, particularly TNF-αdue to its strong association with pain outcomes. Activation of NF-κB signaling pathway, alterations in adrenoceptor expressions, and increase in reactive oxygen species (ROS) were also associated with DLBP through regulation of pro-inflammatory factors and pain-related neuropeptides. Current evidence converges to TNF-α, NF-κB signaling, and ROS-induced pro-inflammation. Major weaknesses in the current literature are the focus on degeneration without pain phenotyping, and lack of association of molecular findings with pain outcomes. PERSPECTIVE: This scoping review identified TNF-α, NF-κB signaling, and ROS-induced pro-inflammation as relevant mechanisms of human discogenic low back pain. Major weaknesses in the current literature are the focus on degeneration without pain phenotyping, and lack of association of molecular findings with pain outcomes.

Ultrashort Echo Time Magnetic Resonance Morphology of Discovertebral Junction in Chronic Low Back Pain Subjects

Background: Chronic low back pain (LBP) has been associated with intervertebral disc (IVD) degeneration, but its association with abnormal morphology at the discovertebral junction (DVJ) is unclear. The goal of this study was to evaluate the DVJ morphology in asymptomatic (Asx) and symptomatic (Sx) subjects for LBP using ultrashort echo time (UTE) MRI. Methods: We recruited 42 subjects (12 Asx and 32 Sx). Lumbar IVD degeneration was assessed using Pfirrmann grading (1 to 5), while the abnormality of DVJ (0 = normal; 1 = focal; 2 = broad abnormality) was assessed using UTE MRI. The effects of LBP and level on the mean IVD and DVJ grades, the correlation between IVD and DVJ grade, and the effect of LBP and age on the number of abnormal DVJs within a subject were determined. Results: IVD grade was higher in Sx subjects (p = 0.013), varying with disc level (p = 0.033), adjusted for age (p < 0.01). Similarly, DVJ grade was also significantly higher in Sx subjects (p = 0.001), but it did not vary with DVJ level (p = 0.7), adjusted for age (p = 0.5). There was a weak positive (rho = 0.344; p < 0.001) correlation between DVJ and IVD grade. The total number of abnormal DVJs within a subject was higher in Sx subjects (p < 0.001), but not with respect to age (p = 0.6) due to a large spread throughout the age range. Conclusions: These results demonstrate the feasibility of using in vivo UTE MRI of the lumbar spine to evaluate the DVJ and the correlation of DVJ with LBP. This study highlights the need for a better understanding of DVJ pathology and the inclusion of DVJ assessment in routine lumbar MRI.

Neuroinflammation and nociception in intervertebral disc degeneration: a review of precision medicine perspective

Intervertebral disc (IVD) degeneration is a major cause of low back pain (LBP), which results in disability worldwide. However, the pathogenesis of IVD degeneration mediating LBP remains unclear. Current conservative treatments and surgical interventions are both to relieve the symptoms and minimise pain; nevertheless, they are unable to reverse the degeneration. Previous studies have shown that inflammation and nociception markers are important indicators of pain mechanisms in IVD degeneration underlying LBP. As such, multiomics profiling allows the discovery of these target markers to understand the key pathological mechanisms mediating IVD degeneration underpinnings of LBP. This article provides insights into a precision medicine approach for identifying and understanding the pathophysiology of IVD degeneration associated with LPB based on the severity of the disease from early and mild to severe degenerative stages. Molecular profiling of key markers in degenerative IVDs based on patient stratification at early, mild, and severe stages will contribute to the identification of target markers associated with signalling pathways in mediating neuroinflammation, innervation, and nociception underlying painful IVD degeneration. This approach will offer an understanding of establishing personalised clinical strategies tailored to the severity of IVD degeneration for the treatment of LBP.

Machine learning-based diagnostic model of lymphatics-associated genes for new therapeutic target analysis in intervertebral disc degeneration

Background

Low back pain resulting from intervertebral disc degeneration (IVDD) represents a significant global social problem. There are notable differences in the distribution of lymphatic vessels (LV) in normal and pathological intervertebral discs. Nevertheless, the molecular mechanisms of lymphatics-associated genes (LAGs) in the development of IVDD remain unclear. An in-depth exploration of this area will help to reveal the biological and clinical significance of LAGs in IVDD and may lead to the search for new therapeutic targets for IVDD.

Methods

Data sets were obtained from the Gene Expression Omnibus (GEO) database. Following quality control and normalization, the datasets (GSE153761, GSE147383, and GSE124272) were merged to form the training set, with GSE150408 serving as the validation set. LAGs from GeneCards, MSigDB, Gene Ontology, and KEGG database. The Venn diagram was employed to identify differentially expressed lymphatic-associated genes (DELAGs) that were differentially expressed in the normal and IVDD groups. Subsequently, four machine learning algorithms (SVM-RFE, Random Forest, XGB, and GLM) were used to select the method to construct the diagnostic model. The receiver operating characteristic (ROC) curve, nomogram, and Decision Curve Analysis (DCA) were used to evaluate the model effect. In addition, we constructed a potential drug regulatory network and competitive endogenous RNA (ceRNA) network for key LAGs.

Results

A total of 15 differentially expressed LAGs were identified. By comparing four machine learning methods, the top five genes of importance in the XGB model (MET, HHIP, SPRY1, CSF1, TOX) were identified as lymphatics-associated gene diagnostic signatures. This signature was used to predict the diagnosis of IVDD with strong accuracy and an area under curve (AUC) value of 0.938. Furthermore, the diagnostic model was validated in an external dataset (GSE150408), with an AUC value of 0.772. The nomogram and DCA further prove that the diagnosis model has good performance and predictive value. Additionally, drug regulatory networks and ceRNA networks were constructed, revealing potential therapeutic drugs and post-transcriptional regulatory mechanisms.

Conclusion

We developed and validated a lymphatics-associated genes diagnostic model by machine learning algorithms that effectively identify IVDD patients. These five key LAGs may be potential therapeutic targets for IVDD patients.

Progress in the Application of Hydrogels in Intervertebral Disc Repair: A Comprehensive Review

PURPOSE OF REVIEW

Intervertebral disc degeneration (IVDD) is a common orthopaedic disease and an important cause of lower back pain, which seriously affects the work and life of patients and causes a large economic burden to society. The traditional treatment of IVDD mainly involves early pain relief and late surgical intervention, but it cannot reverse the pathological course of IVDD. Current studies suggest that IVDD is related to the imbalance between the anabolic and catabolic functions of the extracellular matrix (ECM). Anti-inflammatory drugs, bioactive substances, and stem cells have all been shown to improve ECM, but traditional injection methods face short half-life and leakage problems.

RECENT FINDINGS

The good biocompatibility and slow-release function of polymer hydrogels are being noticed and explored to combine with drugs or bioactive substances to treat IVDD. This paper introduces the pathophysiological mechanism of IVDD, and discusses the advantages, disadvantages and development prospects of hydrogels for the treatment of IVDD, so as to provide guidance for future breakthroughs in the treatment of IVDD.

Efficacy of percutaneous endoscopic lumbar discectomy (PELD) combined with sinuvertebral nerve ablation versus PELD for low back pain in lumbar disc herniation

BACKGROUND

Percutaneous endoscopic lumbar discectomy (PELD) has demonstrated variable efficacy in alleviating low back pain (LBP) associated with lumbar disc herniation (LDH). Sinuvertebral nerve ablation (SNA), which targets the nociceptive pathway implicated in discogenic LBP pathogenesis, has emerged as a potential adjunctive therapy. The efficacy of endoscopic radiofrequency ablation in enhancing PELD for the treatment of LBP in patients with LDH remains unclear.

METHODS

A retrospective cohort study was conducted on LDH patients with concomitant LBP treated at the Spinal Surgery Department, China-Japan Friendship Hospital, from June 2020 to June 2023. Participants were categorized into two groups: PELD combined with SNA (n = 51) and PELD alone (n = 46). Primary outcome measures included the Visual Analog Scale (VAS) for pain, the Japanese Orthopaedic Association (JOA) score, and the Oswestry Disability Index (ODI) at baseline and 1-, 3-, and 6-month follow-ups.

RESULTS

Both groups exhibited significant improvements in VAS, JOA, and ODI scores for LBP and leg pain postoperatively compared to preoperative assessments. Notably, the PELD combined with SNA group demonstrated statistically significant superior outcomes in VAS, JOA, and ODI scores specifically for LBP compared to the PELD group.

CONCLUSION

The combination of PELD with SNA significantly improves LBP outcomes compared to PELD alone in LDH patients. While the observed improvements did not reach the minimal clinically important differences (MICD), these findings suggest that SNA may enhance the efficacy of PELD in LBP management.

Allogenic bone marrow-derived mesenchymal stromal cell-based therapy for patients with chronic low back pain: a prospective, multicentre, randomised placebo controlled trial (RESPINE study)

OBJECTIVES

To assess the efficacy of a single intradiscal injection of allogeneic bone marrow mesenchymal stromal cells (BM-MSCs) versus a sham placebo in patients with chronic low back pain (LBP).

METHODS

Participants were randomised in a prospective, double-blind, controlled study to receive either sham injection or intradiscal injection of 20 million allogeneic BM-MSC, between April 2018 and December 2022. The first co-primary endpoint was the rate of responders defined by improvement of the Visual Analogue Scale (VAS) for pain of at least 20% and 20 mm, or improvement of the Oswestry Disability Index (ODI) of 20% between baseline and month 12. The secondary structural co-primary endpoint was assessed by the disc fluid content measured by quantitative MRI T2, between baseline and month 12. Secondary endpoints included pain VAS, ODI, the Short Form (SF)-36 and the minimal clinically important difference in all timepoints (1, 3, 6, 12 and 24 months). We determined the immune response associated with allogeneic cell injection between baseline and 6 months. Serious adverse events (SAEs) were recorded.

RESULTS

114 patients were randomised (n=58, BM-MSC group; n=56, sham placebo group). At 12 months, the primary outcome was not reached (74% in the BM-MSC group vs 69% in the placebo group; p=0.77). The groups did not differ in all secondary outcomes. No SAE related to the intervention occurred.

CONCLUSIONS

While our study did not conclusively demonstrate the efficacy of allogeneic BM-MSCs for LBP, the procedure was safe. Long-term outcomes of MSC therapy for LBP are still being studied.

TRIAL REGISTRATION NUMBER

EudraCT 2017-002092-25/ClinicalTrials.gov: NCT03737461.

Different Load-Induced Alterations in Intervertebral Discs Between Low Back Pain Patients and Controls: A T2-map Study

STUDY DESIGN

Prospective cohort study.

OBJECTIVE

Investigate load-induced effects in lumbar intervertebral discs (IVDs) and differences between low back pain (LBP) patients and controls.

SUMMARY OF BACKGROUND DATA

T2-map values, obtained from quantitative MRI sequences, reflect IVD tissue composition and integrity. Feasibility studies with T2-mapping indicate different load-induced effects in entire IVDs and posterior IVD parts between LBP patients and controls. Larger studies are required to confirm these findings and increase the understanding of specific characteristics distinguishing IVD changes in LBP patients compared with controls.

MATERIALS AND METHODS

Lumbar IVDs of 178 patients (mean age: 43.8 yr; range: 20-60 yr) with >3 months of LBP and 74 controls (mean age: 40.3 yr; range: 20-60 yr) were imaged with T2-map sequence in a 3T scanner in supine position without axial load, immediately followed by a repeated examination, using the same sequence, with axial load. On both examinations, mean T2-map values were obtained from entire IVDs and from central/posterior IVD parts on the three midsagittal slices in 855 patient IVDs and 366 control IVDs. Load-induced effect was compared with Fold-change ratio and adjusted for IVD-degeneration grade.

RESULTS

Loading induced an increase in T2-map values in both patients and controls. Excluding most extreme values, the ranges varied between -15% and +35% in patients and -11% and +36% in controls (first to 99th percentile). Compared with controls, the T2-map value increase in patients was 2% smaller in entire IVDs (Fold-change: 0.98, P =0.031), and for central and posterior IVD parts 3% (Fold-change: 0.98, P =0.005), respectively, 2% (Fold-change: 0.9, P =0.015) smaller.

CONCLUSIONS

This quantitative study confirmed diverse load-induced behaviors between LBP patients and controls, suggesting deviant biomechanical characteristics between IVDs in patients and controls not only attributed to the global grade of degeneration. These findings are an important step in the continuous work of identifying specific IVD phenotypes for LBP patients.

LEVEL OF EVIDENCE

Level II.

Augmented Cornus officinalis Levels in Liuwei Dihuang Decoction Inhibits Nucleus Pulposus Cell Pyroptosis to Enhance Therapeutic Efficacy Against Intervertebral Disc Degeneration

Background

Intervertebral disc (IVD) degeneration (IVDD) is highly prevalent among the elderly population and stands as a leading cause of low back pain. Our prior studies have highlighted the therapeutic potential of Liuwei Dihuang decoction (LWDHD) and its component Cornus officinalis (CO)-derived compounds in alleviating IVDD and osteoarthritis, suggesting beneficial effects of CO in treating degenerative osteoarthropathies. However, uncertainty remains regarding the optimal CO dosage within LWDHD and its potential mechanism for effectively treating IVDD.

Objective

To ascertain the optimal dosage of CO within LWDHD for enhancing its therapeutic efficacy in treating IVDD, through a comparison of its effects across varied dosages using a mouse IVDD model.

Methods

Eight-week-old male C57BL/6J mice were subjected to a lumbar spine instability surgery to induce an IVDD model and received a modified LWDHD formulation containing varied dosages of CO (original dose of CO, or 5- or 10-time dose of CO (referred to as 1 × CO, 5 × CO, and 10 × CO)) for 8 weeks. The therapeutic efficacy on IVDD was evaluated through changes in lumbar spine function, histopathological morphology, extracellular matrix metabolism, nucleus pulposus cell viability, sensory nerve ingrowth, and nucleus pulposus (NP) cell pyroptosis.

Results

Augmenting CO levels in LWDHD led to a dose-dependent increase in the levels of CO-sourced active compounds in the plasma of mice. The modified LWDHD formulations, particularly the 5 × CO, exhibited a favorable pharmacological effect on lumbar function, structural integrity, ECM composition, NP cell viability, and sensory nerve ingrowth. Importantly, all 3 formulations notably mitigated NP cell pyroptosis by activating NRF2/KEAP1 pathway, with the 5 × CO formulation exhibiting superior efficacy. Additionally, a comprehensive score analysis indicated that 5 × CO formulation achieved the highest score.

Conclusion

These data underscore that elevating the dosage of CO to a specific threshold can enhance the effectiveness of LWDHD in treating IVDD.

A new technique for low back pain in lumbar disc herniation: percutaneous endoscopic lumbar discectomy combined with sinuvertebral nerve ablation

BACKGROUND

Percutaneous endoscopic lumbar discectomy (PELD) has demonstrated efficacy in alleviating leg pain among patients with lumbar disc herniation. Nonetheless, residual back pain persists as a troubling issue for surgeons following the procedure. In the treatment of discogenic back pain, sinuvertebral nerve radiofrequency ablation has shown promising results. Nevertheless, the potential benefit of simultaneously implementing sinuvertebral nerve radiofrequency ablation during PELD surgery to address residual back pain has not been thoroughly investigated in current literature.

METHODS

This retrospective study reviewed Lumbar disc herniation (LDH) patients with low back pain who underwent combined PELD and sinuvertebral nerve ablation in our department between January 2021 and September 2023. Residual low back pain post-surgery was assessed and compared with existing literature.

RESULTS

A total of 80 patients, including 53 males and 27 females, were included in the study. Following surgical intervention, patients demonstrated remarkable improvements in pain and functional parameters. One month post-operatively, the VAS score for low back pain exhibited a 75% reduction (6.45 ± 1.3 to 1.61 ± 1.67), while the VAS score for leg pain decreased by 85% (7.89 ± 1.15 to 1.18 ± 1.26). Notably, the JOA score increased from 12.89 ± 5.48 to 25.35 ± 4.96, and the ODI score decreased form 59.48 ± 9.58 to 20.3 ± 5.37. These improvements were sustained at three months post-operatively. According to the modified Mac Nab criteria, the excellent and good rate was 88.75%. Residual low back pain is observed to be comparatively reduced compared to the findings documented in earlier literature.

CONCLUSION

The combination of percutaneous endoscopic lumbar discectomy and sinuvertebral nerve ablation demonstrates effective improvement in low back pain for LDH patients.

A natural hydrogel complex improves intervertebral disc degeneration by correcting fatty acid metabolism and inhibiting nucleus pulposus cell pyroptosis

The degeneration of intervertebral discs is strongly associated with the occurrence of pyroptosis in nucleus pulposus (NP) cells. This pyroptosis is characterized by abnormal metabolism of fatty acids in the degenerative pathological state, which is further exacerbated by the inflammatory microenvironment and degradation of the extracellular matrix. In order to address this issue, we have developed a fibrin hydrogel complex (FG@PEV). This intricate formulation amalgamates the beneficial attributes of platelet extravasation vesicles, contributing to tissue repair and regeneration. Furthermore, this complex showcases exceptional stability, gradual-release capabilities, and a high degree of biocompatibility. In order to substantiate the biological significance of FG@PEV in intervertebral disc degeneration (IVDD), we conducted a comprehensive investigation into its potential mechanism of action through the integration of RNA-seq sequencing and metabolomics analysis. Furthermore, these findings were subsequently validated through experimentation in both in vivo and in vitro models. The experimental results revealed that the FG@PEV intervention possesses the capability to reshape the inflammatory microenvironment within the disc. It also addresses the irregularities in fatty acid metabolism of nucleus pulposus cells, consequently hindering cellular pyroptosis and slowing down disc degeneration through the regulation of extracellular matrix synthesis and degradation. As a result, this injectable gel system represents a promising and innovative therapeutic approach for mitigating disc degeneration.

Lipid Peroxidation, Reduced Glutathione, and Glutathione Peroxidase Levels in Intervertebral Discs of Patients with Lumbar Degenerative Disc Disease

BACKGROUND Either a reduction in antioxidant levels or an accumulation of reactive oxygen species can heighten susceptibility to oxidative damage in disc cells. To date, no research has investigated the levels of lipid peroxidation products (thiobarbituric acid reactive substances [TBARs]), reduced glutathione (GSH), and glutathione peroxidase (GPx) in excised human lumbar disc tissues affected by degenerative disease. Therefore, this study aimed to evaluate lipid peroxidation products in excised disc tissues from patients with degenerative disc disease. MATERIAL AND METHODS Forty-two patients were enrolled. Patients were divided into lumbar disc degeneration (LDD) and nonlumbar disc degeneration (nonLDD) groups according to Pfirrmann classification. Intervertebral discs were obtained from all patients during the operation and were homogenized for analysis. TBARs levels were measured using fluorometry. GSH levels and GPx activity were quantified spectrophotometrically using a kinetic method. RESULTS TBARs levels in excised discs from LDD patients (5.18±4.14) were significantly higher than those from nonLDD patients (2.56±1.23, P=0.008). The levels of TBARs tended to increase with the severity of degeneration according to the Pfirrmann classification. However, these 2 groups showed no significant differences in reduced glutathione levels or glutathione peroxidase activity (P>0.05). Patients with LDD exhibited a worse health-related quality of life, reflected in lower utility and EQ-VAS scores and higher Oswestry disability index scores. CONCLUSIONS There was a notable increase in lipid peroxidation products in the excised intervertebral discs of patients with LDD. This finding suggests that oxidative stress may contribute to the development of disc degeneration.

Research on the role and mechanism of IL-17 in intervertebral disc degeneration

Intervertebral disc degeneration (IDD) is one of the primary causes of low back pain (LBP), which seriously affects patients' quality of life. In recent years, interleukin (IL)-17 has been shown to be highly expressed in the intervertebral disc (IVD) tissues and serum of patients with IDD, and IL-17A has been shown to promote IDD through multiple pathways. We first searched databases such as PubMed, Cochrane, Embase, and Web of Science using the search terms "IL-17 or interleukin 17″ and "intervertebral discs". The search period ranged from the inception of the databases to December 2023. A total of 24 articles were selected after full-text screening. The main conclusion of the clinical studies was that IL-17A levels are significantly increased in the IVD tissues and serum of IDD patients. The results from the in vitro studies indicated that IL-17A can activate signaling pathways such as the NF-κB and MAPK pathways; promote inflammatory responses, extracellular matrix degradation, and angiogenesis; and inhibit autophagy in nucleus pulposus cells. The main finding of the in vivo experiments was that puncture of animal IVDs resulted in elevated levels of IL-17A within the IVD, thereby inducing IDD. Clinical studies, in vitro experiments, and in vivo experiments confirmed that IL-17A is closely related to IDD. Therefore, drugs that target IL-17A may be novel treatments for IDD, providing a new theoretical basis for IDD therapy.

Frequency of use of discography findings for the diagnosis of low back pain of discogenic origin. Systematic review of the literature

INTRODUCTION

There are different techniques and interpretations of discography findings to determine it positive for the diagnosis of discogenic pain. This study aims to evaluate the frequency of use of discography findings for the diagnosis of low back pain of discogenic origin.

MATERIAL AND METHODS

A systematic review of the literature of the last 17 years was performed in MEDLINE and BIREME. A total of 625 articles were identified, 555 were excluded for duplicates, title and abstract. We obtained 70 full texts of which 36 were included in the analysis after excluding 34 for not meeting the inclusion criteria.

RESULTS

Among the criteria in discography to determine it as positive, 8 studies used only the pain response to the procedure, 28 studies used more than one criterion during discography to consider it as positive, the evaluation of at least one adjacent intervertebral disc with a negative result was necessary in 26 studies to consider a discography as positive. Five studies formally expressed the use of the technique described by SIS/IASP to determine a discography as positive.

CONCLUSIONS

Pain in response to contrast medium injection, assessed with the visual analog pain scale≥6, was the most used criterion in the studies included in this review. Although there are already criteria to determine a discography as positive, the use of different techniques and interpretations of discography findings to determine a positive discography for low back pain of discogenic origin persists.

[Translated article] Frequency of use of discography findings for the diagnosis of low back pain of discogenic origin. Systematic review of the literature

INTRODUCTION

There are different techniques and interpretations of discography findings to determine it positive for the diagnosis of discogenic pain. This study aims to evaluate the frequency of use of discography findings for the diagnosis of low back pain of discogenic origin.

MATERIAL AND METHODS

A systematic review of the literature of the last 17 years was performed in MEDLINE and BIREME. A total of 625 articles were identified, 555 were excluded for duplicates, title and abstract. We obtained 70 full texts of which 36 were included in the analysis after excluding 34 for not meeting the inclusion criteria.

RESULTS

Among the criteria in discography to determine it as positive, 8 studies used only the pain response to the procedure, 28 studies used more than one criterion during discography to consider it as positive, the evaluation of at least one adjacent intervertebral disc with a negative result was necessary in 26 studies to consider a discography as positive. Five studies formally expressed the use of the technique described by SIS/IASP to determine a discography as positive.

CONCLUSIONS

Pain in response to contrast medium injection, assessed with the visual analogue pain scale ≥6, was the most used criterion in the studies included in this review. Although there are already criteria to determine a discography as positive, the use of different techniques and interpretations of discography findings to determine a positive discography for low back pain of discogenic origin persists.

Intradiscal Steroid Injections for Degenerative Disc Disease With Modic Changes: A Retrospective Study of Therapeutic and Diagnostic Features

PURPOSE

Anterior column pain refers to axial low back pain (LBP) originating from the intervertebral disc or vertebral endplates (discogenic or vertebrogenic pain). We sought to assess the safety and effectiveness of intradiscal steroid injection (IDSI) in diagnosing and treating patients with LBP arising from the anterior column.

PATIENTS AND METHODS

This is a retrospective chart review of 66 patients who underwent 77 injections in an outpatient, private practice setting for the treatment of chronic lower back with history and physical exam findings indicating an origin within the anterior column and magnetic resonance imaging (MRI) findings of Modic changes associated with disc degeneration of grade 4 or above on the modified Pfirrmann scale. Patients reported pain as measured by the numerical rating scale (NRS) before the injection, at the time of their follow-up, and their maximum pain relief. The primary outcome was the change in NRS before and after the injections. The secondary outcome determined if the changes in the subjects' NRS met the minimal clinically important change (MCIC) criteria for LBP. We conducted a statistical analysis using a paired sample t-test.

RESULTS

There was a statistically significant difference between the pre-injection and follow-up NRS scores (p < 0.001) and a significant difference between pre-injection and maximum relief NRS scores (p < 0.001). Most subjects (55/77, 71.4%) met the MCIC to relieve their chronic LBP at the time of the follow-up evaluation.

CONCLUSION

For patients with chronic LBP and degenerative endplate changes, IDSIs provided these patients with significant short-term pain relief from pain arising from the anterior column.

Mechanically tough, adhesive, self-healing hydrogel promotes annulus fibrosus repair via autologous cell recruitment and microenvironment regulation

Annulus fibrosus (AF) defect is an important cause of disc re-herniation after discectomy. The self-regeneration ability of the AF is limited, and AF repair is always hindered by the inflammatory microenvironment after injury. Hydrogels represent one of the most promising materials for AF tissue engineering strategies. However, currently available commercial hydrogels cannot withstand the harsh mechanical load within intervertebral disc. In the present study, an innovative triple cross-linked oxidized hyaluronic acid (OHA)-dopamine (DA)- polyacrylamide (PAM) composite hydrogel, modified with collagen mimetic peptide (CMP) and supplied with transforming growth factor beta 1 (TGF-β1) (OHA-DA-PAM/CMP/TGF-β1 hydrogel) was developed for AF regeneration. The hydrogel exhibited robust mechanical strength, strong bioadhesion, and significant self-healing capabilities. Modified with collagen mimetic peptide, the hydrogel exhibited extracellular-matrix-mimicking properties and sustained the AF cell phenotype. The sustained release of TGF-β1 from the hydrogel was pivotal in recruiting AF cells and promoting extracellular matrix production. Furthermore, the composite hydrogel attenuated LPS-induced inflammatory response and promote ECM synthesis in AF cells via suppressing NFκB/NLRP3 pathway. In vivo, the composite hydrogel successfully sealed AF defects and alleviated intervertebral disk degeneration in a rat tail AF defect model. Histological evaluation showed that the hydrogel integrated well with host tissue and facilitated AF repair. The strategy of recruiting endogenous cells and providing an extracellular-matrix-mimicking and anti-inflammatory microenvironment using the mechanically tough composite OHA-DA-PAM/CMP/TGF-β1 hydrogel may be applicable for AF defect repair in the clinic. STATEMENT OF SIGNIFICANCE: Annulus fibrosus (AF) repair is challenging due to its limited self-regenerative capacity and post-injury inflammation. In this study, a mechanically tough and highly bioadhesive triple cross-linked composite hydrogel, modified with collagen mimetic peptide (CMP) and supplemented with transforming growth factor beta 1 (TGF-β1), was developed to facilitate AF regeneration. The sustained release of TGF-β1 enhanced AF cell recruitment, while both TGF-β1 and CMP could modulate the microenvironment to promote AF cell proliferation and ECM synthesis. In vivo, this composite hydrogel effectively promoted the AF repair and mitigated the intervertebral disc degeneration. This research indicates the clinical potential of the OHA-DA-PAM/CMP/TGF-β1 composite hydrogel for repairing AF defects.

Stem cell therapy for degenerative disc disease: Bridging the gap between preclinical promise and clinical potential

Stem cell therapy has gained attention in the field of regenerative medicine due to its potential to restore damaged tissue. This article focuses on the application of stem cell therapy for treating spinal pathologies, particularly intervertebral disc degeneration. Disc degeneration is a major cause of low back pain and is characterized by changes in the matrix and inflammation. Animal studies have demonstrated that the implantation of mesenchymal stem cells (MSCs) yields promising results, including increased disc height, improved hydration, and reduced inflammation. However, the number of clinical trials remains limited, necessitating further research to optimize MSCs therapy. Although preclinical studies offer valuable insights, caution is needed when extrapolating these findings to clinical practice. Stem cell therapy still faces multiple challenges, such as the durability and survival of MSCs upon implantation, uncertain pathways to discogenic differentiation, and the adverse impact of a harsh microenvironment on cell survival. The avascular nature of the intervertebral disc and dynamic loading conditions also affect the adaptation of transplanted cells. Despite these obstacles, stem cell therapy holds promise as a potential treatment for disc degeneration, and ongoing research aims to fill the current gap in conclusive data.

Mechanical Factors Regulate Annulus Fibrosus (AF) Injury Repair and Remodeling: A Review

Low back pain is a common chronic disease that can severely affect the patient's work and daily life. The breakdown of spinal mechanical homeostasis caused by intervertebral disc (IVD) degeneration is a leading cause of low back pain. Annulus fibrosus (AF), as the outer layer structure of the IVD, is often the first affected part. AF injury caused by consistent stress overload will further accelerate IVD degeneration. Therefore, regulating AF injury repair and remodeling should be the primary goal of the IVD repair strategy. Mechanical stimulation has been shown to promote AF regeneration and repair, but most studies only focus on the effect of single stress on AF, and lack realistic models and methods that can mimic the actual mechanical environment of AF. In this article, we review the effects of different types of stress stimulation on AF injury repair and remodeling, suggest possible beneficial load combinations, and explore the underlying molecular mechanisms. It will provide the theoretical basis for designing better tissue engineering therapy using mechanical factors to regulate AF injury repair and remodeling in the future.

Comparative Analysis of Early and Long-Term Outcomes of Patients with Degenerative Lumbar Spine Disease Using the DIAM Stabilizer and Standard Rehabilitation Program: A Preliminary Prospective Randomized Controlled Trial with 1-Year Follow-Up

Low back pain (LBP) is a leading cause of disability and work absenteeism. The cause of LBP may be degeneration of the intervertebral disc. LBP is characterized by considerable variability and tends to develop into chronic pain. Treatment of LBP includes conservative and rehabilitative treatments, surgery, and so-called minimally invasive treatment. One of the most commonly performed procedures is interspinous stabilization using a dynamic interspinous DIAM (device for intervertebral assisted motion) stabilizer. There is still no clear, strong evidence for the effectiveness and superiority of surgical treatment over conservative treatment. This study aimed to compare the early and long-term outcomes of patients with LBP using the DIAM interspinous stabilizer in relation to patients treated conservatively. A group of 86 patients was prospectively randomized into two comparison groups: A (n = 43), treated with the DIAM dynamic stabilizer for degenerative lumbar spine disease (mean age = 43.4 years ± SD = 10.8 years), and B (n = 43), treated conservatively. Pain severity was assessed using the visual analog scale (VAS), whereas disability was assessed using the Oswestry disability index (ODI). The difference in preoperative and postoperative ODI scores ≥ 15 points was used as a criterion for treatment effectiveness, and the difference in VAS scores ≥ 1 point was used as a criterion for pain reduction. In patients under general anesthesia, the procedure only included implantation of the DIAM system. Patients in the control group underwent conservative treatment, which included rehabilitation, a bed regimen, analgesic drug treatment and periarticular spinal injections of anti-inflammatory drugs. It was found that all patients (n = 43) continued to experience LBP after DIAM implantation (mean VAS score of 4.2). Of the 36 patients who experienced LBP with sciatica before the procedure, 80.5% (n = 29) experienced a reduction in pain. As for the level of fitness, the average ODI score was 19.3 ± 10.3 points. As for the difference in ODI scores in the pre-treatment results vs. after treatment, the average score was 9.1 ± 10.6. None of the patients required reoperation at 12 months after surgery. There were no statistically significant differences between the two groups in either early (p = 0.45) or long-term outcomes (p = 0.37). In conclusion, neurosurgical treatment with the DIAM interspinous stabilizer was as effective as conservative treatment and rehabilitation during the one-year follow-up period.

Updates on Pathophysiology of Discogenic Back Pain

Discogenic back pain, a subset of chronic back pain, is caused by intervertebral disc (IVD) degeneration, and imparts a notable socioeconomic health burden on the population. However, degeneration by itself does not necessarily imply discogenic pain. In this review, we highlight the existing literature on the pathophysiology of discogenic back pain, focusing on the biomechanical and biochemical steps that lead to pain in the setting of IVD degeneration. Though the pathophysiology is incompletely characterized, the current evidence favors a framework where degeneration leads to IVD inflammation, and subsequent immune milieu recruitment. Chronic inflammation serves as a basis of penetrating neovascularization and neoinnervation into the IVD. Hence, nociceptive sensitization emerges, which manifests as discogenic back pain. Recent studies also highlight the complimentary roles of low virulence infections and central nervous system (CNS) metabolic state alteration. Targeted therapies that seek to disrupt inflammation, angiogenesis, and neurogenic pathways are being investigated. Regenerative therapy in the form of gene therapy and cell-based therapy are also being explored.

Systematic Review of Platelet-Rich Plasma for Low Back Pain

BACKGROUND

Low back pain (LBP) has a high economic burden and is strongly related to the degenerative process of the spine, especially in the intervertebral disc and of the facet joints. Numerous treatment modalities have been proposed for the management of LBP, and the use of platelet-rich plasma (PRP) has emerged as an innovative therapeutic option for degenerative disease of the spine. The present study aims to evaluate the efficacy of PRP injections in managing low back pain.

METHODS

We conducted a systematic review in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) recommendations, a registered at PROSPERO Systematic Reviews Platform, under number CRD42021268491. The PubMed, Web of Science, and Scopus databases were searched to identify relevant articles, along with hand searching to identify gray literature articles, with no language restrictions. Randomized clinical trials (RCTs), nonrandomized trials (NRTs), and case series (CSs) with more than 10 patients were considered eligible. The quality assessment and the risk of bias of the randomized clinical trials were evaluated using the RoB II tool. An evaluation of the description of the preparation methods was performed using an adapted version of the MIBO checklist.

RESULTS

An electronic database search resulted in 2324 articles, and after the exclusion of noneligible articles, 13 RCTs and 27 NRTs or CSs were analyzed. Of the 13 RCTs, 11 found favorable results in comparison to the control group in pain and disability, one showed no superiority to the control group, and one was discontinued because of the lack of therapeutic effect at eight-week evaluation. Description of the PRP preparation techniques were found in almost all papers. The overall risk of bias was considered high in 2 papers and low in 11. An adapted MIBO checklist showed a 72.7% compliance rate in the selected areas.

CONCLUSIONS

In this systematic review, we analyzed articles from English, Spanish and Russian language, from large databases and grey literature. PRP was in general an effective and safe treatment for degenerative LPB. Positive results were found in almost studies, a small number of adverse events were related, the risk of bias of the RCTs was low. Based on the evaluation of the included studies, we graded as level II the quality of the evidence supporting the use of PRP in LBP. Large-scale, multicenter RCTs are still needed to confirm these findings.

Review: Discogenic Back Pain: Update on Treatment

Purpose of Review

Lower back pain (LBP) has a lifetime prevalence of 80% in the United States population. Discogenic back pain (DBP), a subcategory of LBP, occurs as a result of the interverbal disc degeneration without disc herniation. Diagnosis relies on history, physical exam, and imaging such as MRI, provocative discography, or CT discography.

Recent Findings

Treatment of DBP involves a multifaceted approach with an emphasis on conservative measures including behavioral modification, pharmacologic management, and other non-pharmacologic interventions with invasive therapy reserved for select patients. Due to the paucity of data on the treatment of DBP, treatment also relies on data derived from treatment of chronic LBP (CLBP).

Summary

Despite the scarcity of data for the treatment of DBP, treatments do exist with varying efficacy for DBP. Novel techniques such as the use of biologics may provide another avenue for treatment though further studies are needed to better evaluate the most efficacious regimen for both novel and existing treatments.

Physiological and degenerative loading of bovine intervertebral disc in a bioreactor: A finite element study of complex motions

Intervertebral disc (IVD) degeneration and regenerative therapies are commonly studied in organ-culture experiments with uniaxial compressive loading. Recently, in our laboratory, we established a bioreactor system capable of applying loads in six degrees-of-freedom (DOF) to bovine IVDs, which replicates more closely the complex multi-axial loading of the IVD in vivo. However, the magnitudes of loading that are physiological (able to maintain cell viability) or mechanically degenerative are unknown for load cases combining several DOFs. This study aimed to establish physiological and degenerative levels of maximum principal strains and stresses in the bovine IVD tissue and to investigate how they are achieved under complex load cases related to common daily activities. The physiological and degenerative levels of maximum principal strains and stresses were determined via finite element (FE) analysis of bovine IVD subjected to experimentally established physiological and degenerative compressive loading protocols. Then, complex load cases, such as a combination of compression + flexion + torsion, were applied on the FE-model with increasing magnitudes of loading to discover when physiological and degenerative tissue strains and stresses were reached. When applying 0.1 MPa of compression and ±2-3° of flexion and ±1-2° of torsion the investigated mechanical parameters remained at physiological levels, but with ±6-8° of flexion in combination with ±2-4° of torsion, the stresses in the outer annulus fibrosus (OAF) exceeded degenerative levels. In the case of compression + flexion + torsion, the mechanical degeneration likely initiates at the OAF when loading magnitudes are high enough. The physiological and degenerative magnitudes can be used as guidelines for bioreactor experiments with bovine IVDs.

Efficacy and safety of extracorporeal shockwave therapy in chronic low back pain: a systematic review and meta-analysis of 632 patients

BACKGROUND

Extracorporeal shock wave therapy (ESWT) has been widely used for pain control in musculoskeletal disorders. Whether ESWT can relieve chronic low back pain (CLBP) and improve lumbar function is still unclear. Therefore, we conducted a meta-analysis of relevant studies to comprehensively analyse and determine the efficacy and safety of ESWT for chronic low back pain.

METHODS

Four databases were systematically searched for randomized controlled trials (RCTs) on ESWT for CLBP. The quality of the included studies was evaluated according to Cochrane systematic review criteria, relevant data were extracted, and meta-analysis was performed using RevMan 5.4 software. The primary outcomes were pain intensity, disability status, and mental health. The data were expressed as standardized mean differences (SMD) or weighted mean difference (WMD) and 95% confidence intervals (CI). Heterogeneity was assessed using the I² statistic. If I² ≥ 50%, a random effects model was applied; otherwise, a fixed effects model was used.

RESULTS

Twelve RCTs involving 632 patients were included in this meta-analysis. The ESWT group reported significantly more pain relief than the control group at 4 weeks (WMD =  - 1.04; 95% CI =  - 1.44 to - 0.65; P < 0.001) and 12 weeks (WMD =  - 0.85; 95% CI =  - 1.30 to - 0.41; P < 0.001). Regarding the dysfunction index, ESWT led to significant improvement in lumbar dysfunction compared with the control group at 4 weeks (WMD =  - 4.22; 95% CI =  - 7.55 to - 0.89; P < 0.001) and 12 weeks (WMD =  - 4.51; 95% CI =  - 8.58 to - 0.44; P = 0.03). For mental health, there was no significant difference between the ESWT group and the control group after 4 weeks of intervention (SMD = 1.17; 95% CI =  - 0.10 to 2.45; P = 0.07).

CONCLUSION

This systematic review and meta-analysis found that ESWT provided better pain relief and improved lumbar dysfunction compared with the other interventions included, and no serious adverse effects were found. There was no significant effect of ESWT on the mental health of patients, but we hope to obtain more RCTs for further analysis in the future. Based on the pooled results, we suggest that ESWT is effective and safe for treating chronic low back pain.

The thoracolumbar interfascial block with local anesthesia in osteoporotic vertebral compression fractures treated with percutaneous kyphoplasty provides better analgesia compared with local anesthesia alone: A randomized controlled study

Objective

To evaluate the safety and efficacy of the thoracolumbar interfascial block (TLIPB) in percutaneous kyphoplasty (PKP), and to confirm that the TLIPB further minimizes perioperative pain and residual back pain on the basis of local anesthesia.

Method

From April 2021 to May 2022, 60 patients with osteoporotic vertebral compression fractures were included in this prospective randomized controlled trial. Patients were randomly assigned to a local anesthesia group (A group) or a TLIPB on the basis of local anesthesia group (A + TLIPB group) before PKP. Pain level (visual analog scale, VAS), amount of analgesic rescue drugs (parecoxib), operative time, mean arterial pressure, heart rate, and complications were assessed and compared between the two groups.

Results

Compared with the A group, VAS scores were lower in the A + TLIPB group, respectively, when the trocar punctured the vertebral body (7.4 ± 0.7 vs. 4.5 ± 0.9; P &lt; 0.01), during balloon dilatation (6.6 ± 0.9 vs. 4.6 ± 0.9; P &lt; 0.01), during bone cement injection (6.3 ± 0.6 vs. 4.3 ± 0.8; P &lt; 0.01), 1 h after surgery (3.5 ± 0.7 vs. 2.9 ± 0.7; P &lt; 0.01), and 24 h after surgery (2.5 ± 0.8 vs. 1.9 ± 0.4; P &lt; 0.01). Residual back pain (VAS: 1.9 ± 0.9 vs. 0.9 ± 0.8; P &lt; 0.01) and the incidence of rescue analgesic use (P = 0.02) in the A + TLIPB group were lower compared with the A group. Compared with the A group, mean arterial pressure and heart rate were lower in the A + TLIPB group when the trocar punctured the vertebral body, and with balloon dilatation and bone cement injection; however, there were no statistical differences between the groups 1 and 24 h after surgery. The incidences of bone cement leakage, constipation, and nausea were similar between the two groups. No patient developed infection, neurological injuries, constipation in either group.

Conclusion

The addition of the TLIPB to local anesthesia can further minimize perioperative pain and residual back pain, and reduce perioperative rescue analgesic use. When added to local anesthesia, the TLIPB is an effective and safe anesthetic method for PKP.

Clinical trial registration

This study has been registered in the Clinical Trial registration: ChiCTR-2100044236.

Is a history of episodic low back pain an indicator of Modic changes?

Background

Prior work demonstrated that a history of episodic low back pain was highly indicative of discogenic pain. Recently, there has been more focus on vertebrogenic pain, however little is known about the clinical features of this condition.

Purpose

To determine if a history of severe episodic low back pain correlates with Modic endplate changes on lumbar spine magnetic resonance imaging (MRI), presumed to be a marker of vertebrogenic pain.

Study design

/setting: Retrospective, observational, in vivo study of consecutive patients at outpatient Physical Medicine & Rehabilitation clinics at a single academic spine center.

Patient sample

Consecutive patients who received a lumbar spine MRI between January 1, 2020, and December 31, 2020.

Methods

A retrospective chart review identified patients who received a lumbar spine MRI in 2020. Chart review then determined if patients had a history of episodes of low back pain lasting at least 2 days, or if they had non-episodic low back pain (pain beginning with a gradual onset or after a specific event with continuous symptoms for >3 months). Patients were excluded if they had prior lumbar spine surgery, radicular leg pain without low back pain, indeterminate presentations based on chart review, acute spine fractures, or metastatic spine lesions. For the primary analysis, the MRIs were reviewed and were dichotomized into positive (having for either type 1 or type 2 Modic changes at any level) or negative (no Modic changes at any level).

Results

A total of 111 patients were analyzed. Inter-rater reliability for determining whether a patient's low back pain was episodic was strong (kappa ​= ​0.83), as was inter-rater reliability for determining if a patient had any levels with type 1 or type 2 Modic changes (kappa ​= ​0.81). Seventy-one out of 111 patients had type 1 and/or type 2 Modic changes at one or more spinal levels. The sensitivity of the test (episodic vs non-episodic low back pain) in finding patients with Modic changes was 20% and the specificity was 70%. The diagnostic confidence odds were 1.2, with a diagnostic confidence of 55%. Subgroup analyses for type 1 Modic changes, and for type 2 Modic changes, showed similar values.

Conclusions

A history of episodic low back pain is not a strong indicator for a vertebrogenic etiology.

Natural products can modulate inflammation in intervertebral disc degeneration

Intervertebral discs (IVDs) play a crucial role in maintaining normal vertebral anatomy as well as mobile function. Intervertebral disc degeneration (IDD) is a common clinical symptom and is an important cause of low back pain (LBP). IDD is initially considered to be associated with aging and abnormal mechanical loads. However, over recent years, researchers have discovered that IDD is caused by a variety of mechanisms, including persistent inflammation, functional cell loss, accelerated extracellular matrix decomposition, the imbalance of functional components, and genetic metabolic disorders. Of these, inflammation is thought to interact with other mechanisms and is closely associated with the production of pain. Considering the key role of inflammation in IDD, the modulation of inflammation provides us with new options for mitigating the progression of degeneration and may even cause reversal. Many natural substances possess anti-inflammatory functions. Due to the wide availability of such substances, it is important that we screen and identify natural agents that are capable of regulating IVD inflammation. In fact, many studies have demonstrated the potential clinical application of natural substances for the regulation of inflammation in IDD; some of these have been proven to have excellent biosafety. In this review, we summarize the mechanisms and interactions that are responsible for inflammation in IDD and review the application of natural products for the modulation of degenerative disc inflammation.

Netrin-1 mediates nerve innervation and angiogenesis leading to discogenic pain

Objective

Discogenic low back pain (LBP) is associated with nociceptive nerve fibers that grow into degenerated intervertebral discs (IVD) but the etiopathogenesis of disease is not fully understood. The purpose of this study was to clarify the role of Netrin-1 in causing discogenic LBP.

Methods

The level of nociceptive nerve innervation was examined in disc degenerative patients and rat needle-punctured models by immunohistochemistry. Nucleus pulposus (NP) cells were isolated from IVD tissues of rats and induced degeneration by interleukin-1β (IL-1β) or tumor necrosis factor α (TNFα). The candidate genes related to neuron outgrowth and migration were selected by Next-generation sequencing (NGS). CRISPR/Cas9 was used to knockdown Netrin-1 in NP cells. The impact of Netrin-1 on nerve innervation were evaluated with P2X2、NF200 staining and microfluidics assay. Meanwhile the CD31 staining and transwell assay were used to evaluate the impact of Netrin-1 in angiogenesis. The proteins and RNA extracted from NP cells related to catabolism and anabolism were examined by western blot assay and RT-qPCR experiment. ChIP and luciferase experiments were used to assess the intracellular transcriptional regulation of Netrin-1. Further, a needle-punctured rat model followed by histomorphometry and immunofluorescence histochemistry was used to explore the potential effect of Netrin-1 on LBP in vivo.

Results

The level of nerve innervation was increased in severe disc degenerative patients while the expression of Netrin-1 was upregulated. The supernatants of NP cells stimulated with IL-1β or TNFα containing more Netrin-1 could promote axon growth and vascular endothelial cells migration. Knocking down Netrin-1 or overexpressing transcription factor TCF3 as a negative regulator of Netrin-1 attenuated this effect. The needle-punctured rat model brought significant spinal hypersensitivity, nerve innervation and angiogenesis, nevertheless knocking down Netrin-1 effectively prevented disc degeneration-induced adverse impacts.

Conclusion

Discogenic LBP was induced by Netrin-1, which mediated nerve innervation and angiogenesis in disc degeneration. Knocking down Netrin-1 by CRISPR/Cas9 or negatively regulating Netrin1 by transcription factor TCF3 could alleviate spinal hypersensitivity.

The translational potential of this article

This study on Netrin-1 could provide a new target and theoretical basis for the prevention and treatment for discogenic back pain.

Discogenic Low Back Pain: Anatomy, Pathophysiology and Treatments of Intervertebral Disc Degeneration

Intervertebral disc (IVD) degeneration is a major contributing factor for discogenic low back pain (LBP), causing a significant global disability. The IVD consists of an inner core proteoglycan-rich nucleus pulposus (NP) and outer lamellae collagen-rich annulus fibrosus (AF) and is confined by a cartilage end plate (CEP), providing structural support and shock absorption against mechanical loads. Changes to degenerative cascades in the IVD cause dysfunction and instability in the lumbar spine. Various treatments include pharmacological, rehabilitation or surgical interventions that aim to relieve pain; however, these modalities do not halt the pathologic events of disc degeneration or promote tissue regeneration. Loss of stem and progenitor markers, imbalance of the extracellular matrix (ECM), increase of inflammation, sensory hyperinnervation and vascularization, and associated signaling pathways have been identified as the onset and progression of disc degeneration. To better understand the pain originating from IVD, our review focuses on the anatomy of IVD and the pathophysiology of disc degeneration that contribute to the development of discogenic pain. We highlight the key mechanisms and associated signaling pathways underlying disc degeneration causing discogenic back pain, current clinical treatments, clinical perspective and directions of future therapies. Our review comprehensively provides a better understanding of healthy IVD and degenerative events of the IVD associated with discogenic pain, which helps to model painful disc degeneration as a therapeutic platform and to identify signaling pathways as therapeutic targets for the future treatment of discogenic pain.

Application of single and cooperative different delivery systems for the treatment of intervertebral disc degeneration

Intervertebral disc (IVD) degeneration (IDD) is the most universal pathogenesis of low back pain (LBP), a prevalent and costly medical problem across the world. Persistent low back pain can seriously affect a patient's quality of life and even lead to disability. Furthermore, the corresponding medical expenses create a serious economic burden to both individuals and society. Intervertebral disc degeneration is commonly thought to be related to age, injury, obesity, genetic susceptibility, and other risk factors. Nonetheless, its specific pathological process has not been completely elucidated; the current mainstream view considers that this condition arises from the interaction of multiple mechanisms. With the development of medical concepts and technology, clinicians and scientists tend to intervene in the early or middle stages of intervertebral disc degeneration to avoid further aggravation. However, with the aid of modern delivery systems, it is now possible to intervene in the process of intervertebral disc at the cellular and molecular levels. This review aims to provide an overview of the main mechanisms associated with intervertebral disc degeneration and the delivery systems that can help us to improve the efficacy of intervertebral disc degeneration treatment.

Autologous cultured adipose derived mesenchymal stem cells combined with hyaluronic acid hydrogel in the treatment of discogenic low back pain: a study protocol for a phase II randomised controlled trial

INTRODUCTION

Discogenic low back pain (DLBP) is a common disease, and its occurrence is closely related to intervertebral disc (IVD) degeneration. At present, none of the traditional treatment methods can repair the degenerated IVD. The emergence of stem cell therapy makes it possible to repair and regenerate IVD tissue, among which adipose derived mesenchymal stem cells (ADMSCs) transplantation therapy has become a hot spot of current research. Therefore, this trial aimed to investigate the safety and efficacy of using autologous cultured ADMSCs combined with hyaluronic acid (HA) hydrogel in the treatment of DLBP.

METHODS AND ANALYSIS

This study is a randomised, dose-escalation, placebo-controlled, double-blind, single-centre, phase II clinical trial to evaluate the efficacy and safety of autologous cultured ADMSCs combined with HA hydrogel in the treatment of patients with DLBP. The 100 eligible patients will be randomly divided into three experimental groups with different doses and one placebo control group in a ratio of 1:1:1:1. All patients will undergo liposuction to obtain ADMSCs, followed by autologous cultured ADMSC mixtures or placebo transplantation after 3 weeks. The patients will be followed up to 24 months after the transplant. The primary end point of this trial is the Visual Analogue Scale. Secondary end points include the Oswestry Disability Index, Japanese Orthopaedic Association Scores, the Mos 36-item short form, the Modic classification, Pfirrmann grade, height and segment range of motion of the IVD, vital signs (temperature, pulse, respiration, blood pressure), blood routine, liver and kidney function, immunological examination, urinalysis and treatment emergent adverse events.

ETHICS AND DISSEMINATION

The study protocol has been approved by the Ethics Committee of the First Affiliated Hospital of Dalian Medical University and registered in the Chinese Clinical Trial Registry. Dissemination of the results will be presented at a conference and in peer-reviewed publications.

TRIAL REGISTRATION NUMBER

ChiCTR2200058291.

Oblique lateral interbody fusion stand-alone vs. combined with percutaneous pedicle screw fixation in the treatment of discogenic low back pain

Objective

Oblique lateral interbody fusion (OLIF) has unique advantages in the treatment of discogenic low back pain (DBP). However, there are few studies in this area, and no established standard for additional posterior internal fixation. The purpose of this study was to investigate the efficacy of OLIF stand-alone vs. combined with percutaneous pedicle screw fixation (PPSF) in the treatment of DBP.

Methods

This retrospective case-control study included forty patients. All patients were diagnosed with DBP by discography and discoblock. Perioperative parameters (surgery duration, blood loss, and muscle damage), complications, Visual analog scale (VAS), and Oswestry Disability Index (ODI) were assessed. Imaging data including cage subsidence, cage retropulsion, fusion rate, and adjacent spondylosis degeneration (ASD) were analyzed.

Results

There were 23 patients in the OLIF stand-alone group and 17 patients in the OLIF + PPSF group. The mean surgery duration, blood loss, and muscle damage in the OLIF stand-alone group were significantly better than those in the OLIF + PPSF group (P < 0.05). However, there was no significant difference in the average hospitalization time between the two groups (P > 0.05). There was no significant difference in the VAS and ODI scores between the two groups before surgery (P > 0.05), and VAS and ODI scores significantly improved after surgery (P < 0.05). The VAS and ODI scores in the OLIF stand-alone group were significantly better than those in the OLIF + PPSF group at 1 month (P < 0.05), While there was no significant difference between the two groups at 12 months and last follow up (P > 0.05). At the last follow-up, there was no significant difference in cage subsidence, fusion rate, ASD and complication rate between the two groups (P > 0.05).

Conclusion

OLIF stand-alone and OLIF + PPSF are both safe and effective in the treatment of DBP, and there is no significant difference in the long-term clinical and radiological outcomes. OLIF stand-alone has the advantages of surgery duration, blood loss, muscle damage, and early clinical effect. More clinical data are needed to confirm the effect of OLIF stand-alone on cage subsidence and ASD. This study provides a basis for the clinical application of standard DBP treatment with OLIF.

Axial hypersensitivity is associated with aberrant nerve sprouting in a novel model of disc degeneration in female Sprague Dawley rats

Chronic low back pain is a global socioeconomic crisis and treatments are lacking in part due to inadequate models. Etiological research suggests that the predominant pathology associated with chronic low back pain is intervertebral disc degeneration. Various research teams have created rat models of disc degeneration, but the clinical translatability of these models has been limited by an absence of robust chronic pain-like behavior. To address this deficit, disc degeneration was induced via an artificial annular tear in female Sprague Dawley rats. The subsequent degeneration, which was allowed to progress for 18-weeks, caused a drastic reduction in disc volume. Furthermore, from week 10 till study conclusion, injured animals exhibited significant axial hypersensitivity. At study end, intervertebral discs were assessed for important characteristics of human degenerated discs: extracellular matrix breakdown, hypocellularity, inflammation, and nerve sprouting. All these aspects were significantly increased in injured animals compared to sham controls. Also of note, 20 significant correlations were detected between selected outcomes including a moderate and highly significant correlation (R = 0.59, p < 0.0004) between axial hypersensitivity and disc nerve sprouting. These data support this model as a rigorous platform to explore the pathobiology of disc-associated low back pain and to screen treatments.

Identification of potentially painful disc fissures in magnetic resonance images using machine-learning modelling

PURPOSE

It is suggested that non-specific low back pain (LBP) can be related to nerve ingrowth along granulation tissue in disc fissures, extending into the outer layers of the annulus fibrosus. Present study aimed to investigate if machine-learning modelling of magnetic resonance imaging (MRI) data can classify such fissures as well as pain, provoked by discography, with plausible accuracy and precision.

METHODS

The study was based on previously collected data from 30 LBP patients (age = 26-64 years, 11 males). Pressure-controlled discography was performed in 86 discs with pain-positive discograms, categorized as concordant pain-response at a pressure ≤ 50 psi and for each patient one negative control disc. The CT-discograms were used for categorization of fissures. MRI values and standard deviations were extracted from the midsagittal part and from 5 different sub-regions of the discs. Machine-learning algorithms were trained on the extracted MRI markers to classify discs with fissures extending into the outer annulus or not, as well as to classify discs as painful or non-painful.

RESULTS

Discs with outer annular fissures were classified in MRI with very high precision (mean of 10 repeated testings: 99%) and accuracy (mean: 97%) using machine-learning modelling, but the pain model only demonstrated moderate diagnostic accuracy (mean accuracy: 69%; precision: 71%).

CONCLUSION

The present study showed that machine-learning modelling based on MRI can classify outer annular fissures with very high diagnostic accuracy and, hence, enable individualized diagnostics. However, the model only demonstrated moderate diagnostic accuracy regarding pain that could be assigned to either a non-sufficient model or the used pain reference.

Extracellular vesicle and soluble fractions of adipose tissue-derived mesenchymal stem cells secretome induce inflammatory cytokines modulation in an in vitro model of discogenic pain

BACKGROUND CONTEXT

Mesenchymal stem cells (MSCs) secretome or conditioned medium (CM) is a complex cocktail of different molecules, some of which, particularly those contained in extracellular vesicles, already have proven therapeutic applications.

PURPOSE

CM may well represent promising therapy for discogenic pain and the intention of this work is to assess its therapeutic potential using an in vitro model of this condition.

STUDY DESIGN

This is an experimental study.

METHODS

Our in vitro model comprised nucleus pulposus (NP) and annulus fibrosus (AF) cells inflamed with TNF. To assess the potential therapeutic value of CM and its components, extracellular vesicles (EVs) and soluble culture fraction (SF), cell inflammation took place under 3 different conditions: either in the presence of whole CM, isolated EVs or SF, and concentrations of pro-inflammatory cytokines, metalloproteinases (MMPs) and neurotrophic factors produced in all 3 cases were compared.

RESULTS

In the presence of whole CM, both in vitro gene expression by the NP and AF test cells and analysis of their protein content showed high modulatory effects on inflammation and MMP inhibition. The presence of EVs and SF showed similar but much smaller effects, and this was particularly marked in the case of NP cells.

CONCLUSIONS

Our results show that, compared to EVs and SF, the presence of whole CM has the greatest positive effect on the modulation of pro-inflammatory and catabolic factors. These observations suggest that CM could protect against inflammation and the resulting intervertebral disc (IVD) degeneration that leads to discogenic pain.

CLINICAL SIGNIFICANCE

Many patients' expectations are not met by current non-operative and surgical treatments for discogenic low back pain. We propose the use of the MSCs secretome for assessing its potential as cell-free therapy to treat degenerative disc disease modulating the inflammatory response.

Intervertebral Disc Degeneration: Biomaterials and Tissue Engineering Strategies toward Precision Medicine

Intervertebral disc degeneration is a common cause of discogenic low back pain resulting in significant disability. Current conservative or surgical intervention treatments do not reverse the underlying disc degeneration or regenerate the disc. Biomaterial-based tissue engineering strategies exhibit the potential to regenerate the disc due to their capacity to modulate local tissue responses, maintain the disc phenotype, attain biochemical homeostasis, promote anatomical tissue repair, and provide functional mechanical support. Despite preliminary positive results in preclinical models, these approaches have limited success in clinical trials as they fail to address discogenic pain. This review gives insights into the understanding of intervertebral disc pathology, the emerging concept of precision medicine, and the rationale of personalized biomaterial-based tissue engineering tailored to the severity of the disease targeting early, mild, or severe degeneration, thereby enhancing the efficacy of the treatment for disc regeneration and ultimately to alleviate discogenic pain. Further research is required to assess the relationship between disc degeneration and lower back pain for developing future clinically relevant therapeutic interventions targeted towards the subgroup of degenerative disc disease patients.

Is There Clinical Improvement Associated With Intradiscal Therapies? A Comparison Across Randomized Controlled Studies

STUDY DESIGN

Post hoc comparison using single-site data from 4 multicenter randomized controlled trials.

OBJECTIVES

Discogenic back pain is associated with significant morbidity and medical cost. Several terminated, unreported randomized controlled trials have studied the effect of intradiscal biologic injections. Here we report single-center outcomes from these trials to determine if there is clinical improvement associated with these intradiscal injections.

METHODS

Post hoc comparison was performed using single-site data from 4 similar multi-center randomized controlled trials. All trials evaluated an injectable therapy (growth factor, fibrin sealant, or stem cells) for symptomatic lumbar disc disease with near-identical inclusion and exclusion criteria. Demographics and patient reported outcomes were analyzed across treatment arms postinjection.

RESULTS

A total of 38 patients were treated with biologic agents and 12 were treated with control saline injections. There was a significant decrease in visual analogue score (VAS) pain for both the investigational and saline groups up to 12 months postinjection (P < .01). There was no significant difference in VAS scores between the saline and investigational groups at 12 months. Similarly, there was significant improvement in patient-reported disability scores in both the investigational and saline groups at all time points. There were no significant differences in disability score improvement between the saline and investigational treatment groups at 12 months postinjection.

CONCLUSIONS

A single-center analysis of 4 randomized controlled studies demonstrated no difference in outcomes between therapeutic intradiscal agents (growth factor, fibrin sealant, or stem cells) and control saline groups. In all groups, patient reported pain and disability scores decreased significantly. Future studies are needed to evaluate the therapeutic benefit of any intradiscal injections.

Percutaneous lumbar annular puncture: A rat model to study intervertebral disc degeneration and pain-related behavior

Background

Previous animal models of intervertebral disc degeneration (IDD) rely on open surgical approaches, which confound the degenerative response and pain behaviors due to injury to surrounding tissues during the surgical approach. To overcome these challenges, we developed a minimally invasive percutaneous puncture procedure to induce IDD in a rat model.

Methods

Ten Fischer 344 male rats underwent percutaneous annular puncture of lumbar intervertebral discs (IVDs) at L2-3, L3-4, and L4-5. Ten unpunctured rats were used as controls. Magnetic resonance imagings (MRIs), serum biomarkers, and behavioral tests were performed at baseline and 6, 12, and 18 weeks post puncture. Rats were sacrificed at 18 weeks and disc histology, immunohistochemistry, and glycosaminoglycan (GAG) assays were performed.

Results

Punctured IVDs exhibited significant reductions in MRI signal intensity and disc volume. Disc histology, immunohistochemistry, and GAG assay results were consistent with features of IDD. IVD-punctured rats demonstrated significant changes in pain-related behaviors, including total distance moved, twitching frequency, and rearing duration.

Conclusions

This is the first reported study of the successful establishment of a reproducible rodent model of a percutaneous lumbar annular puncture resulting in discogenic pain. This model will be useful to test therapeutics and elucidate the basic mechanisms of IDD and discogenic pain.

Clinical outcomes following intradiscal injections of higher-concentration platelet-rich plasma in patients with chronic lumbar discogenic pain

PURPOSE

This study aimed to assess clinical outcomes following intradiscal injections of higher-concentration (> 10 ×) platelet-rich plasma (PRP) in patients with chronic lumbar discogenic pain and to compare outcomes with a historical cohort.

METHODS

This retrospective study included 37 patients who received intradiscal injections of higher-concentration (> 10 ×) PRP and had post-procedure outcomes data (visual numerical scale pain score, Functional Rating Index [FRI], and NASS Patient Satisfaction Index). Outcomes were compared to a historical cohort of 29 patients who received intradiscal injections of < 5X PRP.

RESULTS

Pain and FRI scores significantly improved by 3.4 ± 2.5 and 46.4 ± 27.6, respectively, at 18.3 ± 13.3 months following intradiscal injections of > 10 × PRP (p < 0.001). These improvements were greater than those reported by the historical cohort (1.7 ± 1.6 and 33.7 ± 12.3; p = 0.004 and 0.016, respectively). Additionally, the satisfaction rate was higher in patients receiving > 10 × PRP compared to those receiving < 5 × PRP (81% vs. 55%; p = 0.032).

CONCLUSIONS

Findings from this study suggest that clinical outcomes can be optimized by using PRP preparations that contain a higher concentration of platelets. Further research is needed to continue to optimize the composition of PRP used to treat patients with lumbar disc disease.

Efficacy of the Gelstix nucleus augmentation device for the treatment of chronic discogenic low back pain: protocol for a randomised, sham-controlled, double-blind, multicentre trial

INTRODUCTION

Discogenic pain is the cause of pain in 26%-40% of patients with for low back pain. Consensus about treatment of chronic discogenic low back pain is lacking and most treatment alternatives are supported by limited evidence. The percutaneous implantation of hydrogels into the nucleus pulposus represents a promising regenerative intradiscal therapy. The hydrogel 'GelStix' is composed primarily of hydrolyzed polyacrylonitrile and acts as a reservoir of hydration, producing increased pressure and improved pH balance, potentially leading to disc preservation. We hypothesise that treatment with GelStix will lead to greater reduction in pain intensity at 6 months post-treatment compared with patients receiving sham treatment.

METHODS AND ANALYSIS

This is a parallel group, randomised sham-controlled double-blind, multicentre trial to assess whether the GelStix device is superior to sham in reducing pain intensity in patients with chronic discogenic low back pain. The study will be conducted in two regional hospitals in Europe. Seventy-two participants will be randomised in a 1:1 ratio. The primary outcome will be the change in pain intensity between preoperative baseline and at 6 months postintervention. Secondary outcomes were disability, quality of life, the patient's global impression of change scale, the use of pain medication and the disc degeneration process assessed by means of MRI. For change in pain intensity, disability, health-related quality of life and disc height, mean values will be compared between groups using linear regression analysis, adjusted for treatment centre.

ETHICS AND DISSEMINATION

Ethics approval was obtained from the Ethics Committee of the Canton Ticino, Switzerland (CE2982) and by the Medical Ethical Committee Arnhem-Nijmegen, the Netherlands (2016-2944). All patients that agree to participate will be asked to sign an informed consent form. Results will be disseminated through international publications in peer-reviewed journals, in addition to international conference presentations.

TRIAL REGISTRATION NUMBER

NCT02763956.

PROTOCOL VERSION

7.1, 18 November 2020.

Effectiveness of intradiscal platelet rich plasma for discogenic low back pain without Modic changes: A randomized controlled trial

Objective

To determine if autologous platelet-rich plasma (PRP) injection into a degenerative intervertebral disc, without Modic changes on magnetic resonance imaging (MRI), improve pain and function.

Design

Prospective, randomized controlled study.

Setting

Outpatient spine practice (Stichting Rugpoli, Netherlands).

Participants

Adults with chronic low back pain referred to Stichting Rugpoli, according to the Dutch General Practitioners Guidelines, unresponsive to conservative treatment, without Modic changes on MRI.

Methods

Provocation discography was performed to confirm the suspected disc was the source of pain. Participants were randomized to receive 1.0 ​cc intradiscal PRP (intervention) or 1.0 ​cc Saline with 0.2g Kefzol (control). Data on pain (Numeric Rating Scale), physical function (Roland Morris Disabilty Questionnaire, RMDQ), and participants' general perceived health (SF-12) were collected at 1 week, 4 weeks, 2 months, 6 months, 9 months and 1 year. A repeated-measures analysis (mixed model) was used for comparing the outcomes of the groups.

Results

Of the initial 98 (49 intervention, 49 control) patients randomized, 89 (91%) (44 intervention, 45 control) with complete outcome data were analyzed. Groups were balanced at baseline. After twelve months no differences between groups were found in the average pain (improved 21/44 in intervention vs 16/45 in control, p ​= ​0.244), the disability scores (RMDQ minimal 3 points improvement 22/44 in intervention vs 24/45 in control, p ​= ​0.753) and the SF-12 (mean difference physical health -1.19, 95% CI -5.39 to 2.99, p ​= ​0.721, and mental health -0.34, 95% CI -3.99 to 3.29, p ​= ​0.834). One serious adverse event occurred (spondylodiscitis) after intervention.

Conclusion

Participants who received intradiscal PRP showed no significant improvement in pain or functionality compared to the control group at 1 year follow up.

Texture Analysis of Magnetic Resonance Images Enables Phenotyping of Potentially Painful Annular Fissures

STUDY DESIGN

Retrospective analysis of prospectively collected data.

OBJECTIVE

To investigate whether intervertebral disc (IVD) image features, extracted from magnetic resonance (MR) images, can depict the extension and width of annular fissures and associate them to pain.

SUMMARY OF BACKGROUND DATA

Annular fissures are suggested to be associated with low back pain (LBP). Magnetic resonance imaging (MRI) is a sensitive method, yet fissures are sometimes unobservable in T2-weighted MR-images, even though fissure information is present in the image. Image features can mathematically be calculated from MR-images and might reveal fissure characteristics.

METHODS

Forty four LBP patients who underwent MRI, low-pressure discography (<50 psi), and computed tomography (CT) sequentially in 1 day, were reviewed. After semi-automated segmentation of 126 discs, image features were extracted from the T2-weighted images. The number of image features was reduced with principle component analysis (PCA). CT-discograms were graded and dichotomized regarding extension and width of fissures. IVDs were divided into fissures extending to outer annulus versus short/no fissures. Fissure width was dichotomized into narrow (<10%) versus broad fissures (>10%), and into moderately broad (10%-50%) versus very broad fissures (>50%). Logistic regression was performed to investigate if image features could depict fissure extension to outer annulus and fissure width. As a sub-analysis, the association between image features used to depict fissure characteristics and discography-provoked pain-response were investigated.

RESULTS

Fissure extension could be depicted with sensitivity/specificity = 0.97/0.77 and area under curve (AUC) = 0.97. Corresponding results for width depiction were sensitivity/specificity = 0.94/0.39 and 0.85/0.62, and AUC = 0.86 and 0.81 for narrow versus broad and moderately broad versus very broad fissures respectively. Pain prediction with image features used for depicting fissure characteristics showed sensitivity/specificity = 0.90/0.36, 0.88/0.4, 0.93/0.33; AUC = 0.69, 0.75, and 0.73 respectively.

CONCLUSION

Standard MR-images contains fissure information associated to pain that can be depicted with image features, enabling non-invasive phenotyping of potentially painful annular fissures.Level of Evidence: 2.

Efficacy Analysis of Percutaneous Endoscopic Spinal Surgery for Young Patients with Discogenic Low Back Pain

Purpose

To evaluate the application value of percutaneous endoscopic spinal surgery for young patients with discogenic low back pain (DLBP) and to judge its clinical efficacy.

Methods

We retrospectively analyzed young patients with single-segment discogenic lumbago from July 2018 to June 2020 in our department who underwent percutaneous endoscopic surgery according to the inclusion and exclusion criteria. We finally enrolled 20 patients. The follow-up time was 6–30 months. In all patients, we recorded the visual analog scale (VAS) score for waist pain and the Oswestry Disability Index (ODI) preoperatively, immediately postoperatively and at the last follow-up. We used the modified MacNab criteria to assess the curative effect at the last follow-up.

Results

All 20 patients underwent successful operations without complications. No recurrence was observed during follow-up. The VAS score of low back pain was 5.05±1.19 points before surgery, 1.50±051 points immediately after surgery, and 1.10±0.72 points at the last follow-up (P < 0.05 preoperative vs both postoperative). At the last follow-up, the VAS scores of all 20 patients were ≤2, and 4 patients had no pain. The ODI was 46.66±7.03% before surgery, 9.78±4.05% immediately after surgery, and 4.11±3.18% at the last (P < 0.05, preoperative vs both postoperative). According to the evaluation under the modified MacNab standard, the good–excellent rate of clinical efficacy at the last follow-up was 95%.

Conclusion

Percutaneous endoscopic spinal surgery can significantly improve the symptoms and dysfunction of young patients with DLBP and has little effect on the biomechanical stability of the lumbar spine. This surgery has great clinical application value.

Intervertebral Disc-on-a-Chip as Advanced In Vitro Model for Mechanobiology Research and Drug Testing: A Review and Perspective

Discogenic back pain is one of the most diffused musculoskeletal pathologies and a hurdle to a good quality of life for millions of people. Existing therapeutic options are exclusively directed at reducing symptoms, not at targeting the underlying, still poorly understood, degenerative processes. Common intervertebral disc (IVD) disease models still do not fully replicate the course of degenerative IVD disease. Advanced disease models that incorporate mechanical loading are needed to investigate pathological causes and processes, as well as to identify therapeutic targets. Organs-on-chip (OoC) are microfluidic-based devices that aim at recapitulating tissue functions in vitro by introducing key features of the tissue microenvironment (e.g., 3D architecture, soluble signals and mechanical conditioning). In this review we analyze and depict existing OoC platforms used to investigate pathological alterations of IVD cells/tissues and discuss their benefits and limitations. Starting from the consideration that mechanobiology plays a pivotal role in both IVD homeostasis and degeneration, we then focus on OoC settings enabling to recapitulate physiological or aberrant mechanical loading, in conjunction with other relevant features (such as inflammation). Finally, we propose our view on design criteria for IVD-on-a-chip systems, offering a future perspective to model IVD mechanobiology.

Is There Any Relationship between Plasma IL-6 and TNF-α Levels and Lumbar Disc Degeneration? A Retrospective Single-Center Study

Intervertebral disc degeneration (IDD) is one of the most common degenerative diseases all over the world. A growing number of studies have proved that large amounts of cytokines are produced during the development of IDD, and the inflammatory responses induced by these cytokines aggravate the occurrence and development of the disc degeneration. In this retrospective single-center study, a total of 182 lumbar spine cases were retrospectively reviewed between July 2020 and October 2021. An appropriate cutoff value was found for discriminating severity of IDD by William rank-sum test and locally weighted scatterplot smoothing algorithm. The cumulative grade was also calculated by summing Pfirrmann grades for all lumbar spine intervertebral discs. It was found that high-score group (total score > 18) plasma interleukin-6 (IL-6) concentration was significantly higher than that of the low-score group (total score ≤ 18) (9.6 ± 1.75 vs. 5.40 ± 0.61 pg/ml, p = 0.002), tumor necrosis factor-α (TNF-α) following the same trend (5.27 ± 1.48 vs. 2.97 ± 0.23, p = 0.006), which was most pronounced in the upper lumbar intervertebral discs (L1-3). In the entire sample, preoperative IL-6 concentration was significantly higher than that of the postoperation (p < 0.001), while the TNF-α was the opposite (p = 0.039). It was also found that there were significant differences in the two groups with respect to age and hypertension (p < 0.001 and p = 0.037). In conclusion, this study preliminarily indicated the relationship between IL-6 and TNF-α and the severity of lumbar disc degeneration.

Local Delivery of Senolytic Drug Inhibits Intervertebral Disc Degeneration and Restores Intervertebral Disc Structure

Intervertebral disc (IVD) degeneration (IVDD) is a leading cause of chronic low back pain. There is a strong clinical demand for more effective treatments for IVDD as conventional treatments provide only symptomatic relief rather than arresting IVDD progression. This study shows that senolytic therapy with local drug delivery can inhibit IVDD and restore IVD integrity. ABT263, a senolytic drug, is loaded in poly(lactic-co-glycolic acid) nanoparticles (PLGA-ABT) and intradiscally administered into injury-induced IVDD rat models. The single intradiscal injection of PLGA-ABT may enable local delivery of the drug to avascular IVD, prevention of potential systemic toxicity caused by systemic administration of senolytic drug, and morbidity caused by repetitive injections of free drug into the IVD. The strategy results in the selective elimination of senescent cells from the degenerative IVD, reduces expressions of pro-inflammatory cytokines and matrix proteases in the IVD, inhibits progression of IVDD, and even restores the IVD structure. This study demonstrates for the first time that local delivery of senolytic drug can effectively treat senescence-associated IVDD. This approach can be extended to treat other types of senescence-associated degenerative diseases.