Correlation between intervertebral disc degeneration and bone mineral density difference: a retrospective study of postmenopausal women using an eight-level MRI-based disc degeneration grading system

Strontium alginate hydrogel containing psoralen has superior mechanical properties and immunomodulatory functions to alleviate intervertebral disc degeneration

Changes in mechanical properties, inflammation, and oxidative stress are key factors in the progression of intervertebral disc degeneration, while phytoestrogens have shown promising therapeutic potential. In this study, we propose the synthesis of a hydrogel using psoralen that can mimic the mechanical properties of human intervertebral disc nucleus pulposus tissue. This hydrogel exhibits anti-inflammatory and antioxidant properties, aiming to alleviate intervertebral disc degeneration. Firstly, we synthesized a strontium alginate hydrogel containing psoralen (SA@Sr/PSO). The material was characterized using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), drug release testing, and mechanical property assessment. The optimal drug loading concentration was determined through CCK-8 assay and live/dead staining. The biological functions were assessed using enzyme-linked immunosorbent assay (ELISA), quantitative real-time PCR, and immunofluorescence staining. The results showed that the synthesized SA@Sr/PSO exhibited a porous structure and favorable water absorption, with excellent elasticity and mechanical properties. Cell experiments demonstrated that SA@Sr/PSO promoted cell proliferation, downregulated the expression of IL-1β, IL-6, iNOS, and NO, and upregulated the expression of IL-10, Arg-1, and CD206. The DPPH assay confirmed that the hydrogel can inhibit oxidative stress. The successful synthesis of SA@Sr/PSO, with its excellent mechanical properties and biological functions, improves intervertebral disc degeneration.

New-Occurrence of Postoperative Modic Changes and Its Influence on the Surgical Prognosis After Percutaneous Endoscopic Lumbar Disc Discectomy

OBJECTIVES

Lumbar disc herniation (LDH) is a common degenerative spinal disease in clinical practice. This study aims to investigate the impact of Modic changes (MCs) on postoperative recovery and disease recurrence following percutaneous endoscopic lumbar disc discectomy (PELD), providing important insights for improving the management of chronic low back pain. This study investigates the 1-year progression rate of MCs after PELD and their impact on surgical outcomes and recurrence.

METHODS

This retrospective cohort study analyzed data from 419 patients with single-segment lumbar disc herniation who underwent PELD between January 2019 and December 2022. Lumbar MRI assessed preoperative and postoperative MCs. Pain levels and surgical outcomes were evaluated using the visual analog scale, Oswestry Disability Index, and Macnab criteria. Univariate analysis explored the relationship between postoperative MCs and pain, while subgroups investigated the associations between postoperative efficacy, recurrence, and MCs type and area.

RESULTS

One-year follow-up revealed that the probability of MCs postsurgery was 24.8%. Patients with postoperative MCs had significantly lower pain scores compared with the control group (p < 0.05). Univariate analysis indicated that the type and area of postoperative MCs were risk factors for poor outcomes in PELD patients (p < 0.05). During the 1-year follow-up, recurrence rates in the no-MCs and MCs groups were 3.8% and 9.6%, respectively (p < 0.05). Univariate analysis concluded that the area of postoperative MCs was a risk factor for PELD recurrence.

CONCLUSION

The postoperative MCs, as a risk factor, may have a detrimental effect on the surgical efficacy and short-term recurrence of LDH following PELD based on a large sample. Furthermore, the harmful effect is affected by the area and type of the postoperative MCs.

Regional variations of mechanical responses of IVD to 7 different motions: An in vivo study combined with FEA and DFIS

The abnormal mechanical behaviour of a lumbar intervertebral disc (IVD) is commonly recognized as a direct indicator of intervertebral disc degeneration (IDD). However, current methods cannot evaluate the patient-specific mechanical performance of an IVD in vivo during movement. This study establishes a patient-specific (PS) model that combines the kinematics parameters of the lumbar spine obtained with a dual fluoroscopic imaging system (DFIS) and a finite-element (FE) method for the first time to reveal the mechanical behaviours of IVDs in vivo under seven motions. Three healthy participants were recruited for this study. CT images were obtained to create finite-element models of L3-L5 spine segments. Meanwhile, participants were required to take specific positions including upright standing, flexion, extension, left and right lateral bending, as well as left and right axial torsion in the DFIS. The in vivo kinematic parameters, calculated by registering the CT images with images obtained with DFIS, were considered as loading conditions in FE simulations. Significant differences of von Mises stresses and principal strains were found between PS model and GN model which employing a generalized moment as loading conditions, former resulting in up to 76.74 % lower strain than the GN model. Also, considerable differences were observed for five anatomical regions of the IVD (L3-L5). Under all motions, the stress in the centre region (nucleus pulposus) was the lowest, while the stress in the posterior region was the highest in extension motion. Therefore, activities such as stretching with an extension, should be avoided by patients with a herniated disc, in which the posterior region was the herniation site. The PS model combining in vivo kinematics and FE simulations shows the potential in the design and assessment of patient-specific implants.

Sdc4 deletion perturbs intervertebral disc matrix homeostasis and promotes early osteopenia in the aging mouse spine

Syndecan 4 (SDC4), a cell surface heparan sulfate proteoglycan, is known to regulate matrix catabolism by nucleus pulposus cells in an inflammatory milieu. However, the role of SDC4 in the aging spine has never been explored. Here we analyzed the spinal phenotype of Sdc4 global knockout (KO) mice as a function of age. Micro-computed tomography showed that Sdc4 deletion severely reduced vertebral trabecular and cortical bone mass, and biomechanical properties of vertebrae were significantly altered in Sdc4 KO mice. These changes in vertebral bone were likely due to elevated osteoclastic activity. The histological assessment showed subtle phenotypic changes in the intervertebral disc. Imaging-Fourier transform-infrared analyses showed a reduced relative ratio of mature collagen crosslinks in young adult nucleus pulposus (NP) and annulus fibrosus (AF) of KO compared to wildtype discs. Additionally, relative chondroitin sulfate levels increased in the NP compartment of the KO mice. Transcriptomic analysis of NP tissue using CompBio, an AI-based tool showed biological themes associated with prominent dysregulation of heparan sulfate GAG degradation, mitochondria metabolism, autophagy, endoplasmic reticulum (ER)-associated misfolded protein processes and ER to Golgi protein processing. Overall, this study highlights the important role of SDC4 in fine-tuning vertebral bone homeostasis and extracellular matrix homeostasis in the mouse intervertebral disc.

Rotation-traction manipulation induced intradiskal pressure changes in cervical spine-an in vitro study

Objective: Evaluate the effect of rotation-traction manipulation on intradiskal pressure in human cervical spine specimen with different force and duration parameters, and compare the intradiskal pressure changes between rotation-traction manipulation and traction. Methods: Seven human cervical spine specimens were included in this study. The intradiskal pressure was measured by miniature pressure sensor implanting in the nucleus pulposus. rotation-traction manipulation and cervical spine traction were simulated using the MTS biomechanical machine. Varied thrust forces (50N, 150N, and 250N) and durations (0.05 s, 0.1 s, and 0.15 s) were applied during rotation-traction manipulation with Intradiscal pressure recorded in the neutral position, rotation-anteflexion position, preloading, and thrusting phases. Futuremore, we documented changes in intradiscal pressure during cervical spine traction with different loading forces (50N, 150N, and 250N). And a comparative analysis was performed to discern the impact on intradiscal pressure between manipulation and traction. Results: Manipulation application induced a significant reduction in intradiscal pressure during preloading and thrusting phases for each cervical intervertebral disc (p < 0.05). When adjusting thrust parameters, a discernible decrease in intradiscal pressure was observed with increasing thrust force, and the variations between different thrust forces were statistically significant (p < 0.05). Conversely, changes in duration did not yield a significant impact on intradiscal pressure (p > 0.05). Additionally, after traction with varying loading forces (50N, 150N, 250N), a noteworthy decrease in intradiscal pressure was observed (p < 0.05). And a comparative analysis revealed that rotation-traction manipulation more markedly reduced intradiscal pressure compared to traction alone (p < 0.05). Conclusion: Both rotation-traction manipulation and cervical spine traction can reduce intradiscal pressure, exhibiting a positive correlation with force. Notably, manipulation elicits more pronounced and immediate decompression effect, contributing a potential biomechanical rationale for its therapeutic efficacy.

Association between lumbar endplate damage and bone mineral density in patients with degenerative disc disease

BACKGROUND

To explore the independent association between lumbar endplate damage and bone mineral density (BMD) in patients with degenerative disc disease (DDD).

METHODS

This retrospective investigation was based out of a prospectively collected database from the Affiliated Kunshan Hospital of Jiangsu University. Data from 192 DDD patients, collected between December 2018 and January 2022, were chosen for the final analysis. The average total endplate score (TEPS) of lumbar(L) 1-L4 was assessed by magnetic resonance imaging (MRI), and represents the extent of endplate damage. Osteoporosis severity was assessed via the L1-L4 BMD evidenced by dual-energy x-ray absorptiometry (DXA). Other analyzed information included gender, age, body mass index (BMI), and osteophyte score (OSTS). Uni- and multivariate linear regression analyses were employed to evaluate the association between average TEPS and BMD of L1-L4. Moreover, the generalized additive model (GAM) was employed for non-linear association analysis.

RESULTS

Upon gender, age, BMI, and OSTS adjustments, a strong independent inverse relationship was observed between average TEPS and BMD (β, -0.021; 95% CI, -0.035 to -0.007, P-value = 0.00449). In addition, the gender stratification analysis revealed a linear relationship in males, and a non-linear relationship in females. Specifically, there was a significantly stronger negative relationship between average TEPS and BMD in females, when the average TEPS was < 3.75 (β, -0.063; 95% CI, -0.114 to -0.013; P-value = 0.0157). However, at an average TEPS > 3.75, the relationship did not reach significance (β, 0.007; 95% CI, -0.012 to 0.027; P-value = 0.4592).

CONCLUSIONS

This study demonstrated the independent negative association between average TEPS and BMD values of L1-L4. Upon gender stratification, a linear relationship was observed in males, and a non-linear association in females. The findings reveal that patients with osteoporosis or endplate damage require more detailed examinations and treatment regimen.

The Relationship Between Bone Mineral Density and Lumbar Disc Herniation in Postmenopausal Women

INTRODUCTION

In previous studies, the relationship between BMD (bone mineral density) and LDH (lumbar disc herniation) has been investigated in young people, except for postmenopausal women. The aim of this study was to evaluate this association in postmenopausal women.

METHODS

A cross-sectional analysis of 545 consecutive postmenopausal women was performed at a single center. The study included patients aged 45 to 85 with low back pain. Age, weight, height, L1-L4 BMD, L1-L4 T-score, L1-L4 Z-score, femoral neck BMD, femoral neck T-score, and femoral neck Z-score of patients were collected. MRI scans were assessed for the diagnosis of LDH. To explore the impact of the number of herniated segments, patients with LDH were further divided into single-level and multi-level LDH groups.

RESULTS

Five hundred and thirteen postmenopausal women were included in the final analysis. The mean age of the patients was 61.3±8.6 years in the LDH group and 58.4±7.8 years in the non-LDH group (p=0.001). The LDH group had higher lumbar (p<0.001) and femoral neck (p<0.05) BMD, T, and Z-scores than the non-LDH group. In binary logistic regression analysis, age, lumbar, and femoral neck BMD were significantly associated with LDH (p<0.001, p=0.03, and p=0.040, respectively). Patients with multi-level herniation had significantly higher rates of obesity (BMI ≥30) compared to patients with single-level herniation (58.0% vs. 47.0%; p=0.031). However, in terms of obesity rates, the LDH group and the non-LDH group were statistically similar (53.9% vs. 54.2%; p=0.961). There was no association between the single and multi-level herniation groups in terms of L1-4 and femoral neck BMD (p=0.760 and 0.435, respectively).

CONCLUSION

Higher lumbar bone mineral density and higher femoral neck bone mineral densities were found to be associated with lumber disc herniation in postmenopausal women with low back pain. These results suggest that bone mineral density assessment may be useful in clinical practice to determine which patients are at higher risk of lumbar disc herniation.

Feasibility Study of 3D FACT and IVIM Sequences in the Evaluation of Female Osteoporosis

BACKGROUND

The aim of this study is to search for the predictive value of 3D fat analysis and calculation technique (FACT) and intravoxel incoherent motion (IVIM) parameters in identifying osteoporosis in women.

METHODS

We enrolled 48 female subjects who underwent 3.0 T MRI, including 3D FACT and IVIM sequences. Bone mineral density (BMD) values and Fracture Risk Assessment (FRAX) scores were obtained. Proton density fat fraction (PDFF) in the bone marrow and the real diffusion (D) value of intervertebral discs were measured on 3D FACT and IVIM images, respectively. Accuracy and bias were assessed by linear regression analysis and Bland-Altman plots. Intraclass correlation coefficients were used to assess the measurements' reproducibility. Spearman's rank correlation was applied to explore the correlation. MRI-based parameters were tested for significant differences among the three groups using ANOVA analyses. A receiver operating characteristic (ROC) analysis was performed.

RESULTS

The PDFF of the vertebral body showed a negative correlation with BMD (R = -0.393, p = 0.005) and a positive correlation with the FRAX score (R = 0.706, p < 0.001). The D value of intervertebral discs showed a positive correlation with BMD (R = 0.321, p = 0.024) and a negative correlation with the FRAX score (R = -0.334, p = 0.019). The area under the curve values from the ROC analysis showed that the 3D FACT and IVIM sequences could accurately differentiate between normal and osteoporosis (AUC = 0.88 using the PDFF; AUC = 0.77 using the D value). The PDFF value demonstrated a sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of 78.6%, 89.5%, 84.6%, and 85.0%, respectively, in its ability to predict osteoporosis. The D value had a sensitivity, specificity, PPV, and NPV of 63.16%, 92.9%, 65.0%, and 77.8%, respectively, for predicting osteoporosis.

CONCLUSIONS

The 3D FACT- and IVIM-measured PDFF and D values are promising biomarkers in the assessment of bone quality and fracture risk.