Endplate defects, not the severity of spinal stenosis, contribute to low back pain in patients with lumbar spinal stenosis

Quantitative evaluation of risk factors for low back pain in young patients using synthetic magnetic resonance imaging and proton density fat fraction analyses

Background

Lumbar intervertebral disc and paravertebral muscle degeneration are common causes of chronic low back pain (CLBP). However, the exact etiology of CLBP in young patients remains unclear. Identifying the risk factors for CLBP in young patients could expedite the development of effective preventive recommendations.

Objectives

To identify the factors influencing the presence and severity of CLBP in young patients by analyzing the associations between the fat content of the paravertebral muscles, T2 value of the lumbar intervertebral disc (LIVD), and visual analog scale (VAS) score.

Design

Data for 23 patients diagnosed with CLBP were compared to those of 20 healthy young individuals.

Methods

The T2 values of the LIVD and fat content of the psoas major (PM), multifidus (MF), and erector spinae (ES) muscles for 23 young patients with CLBP and 20 healthy individuals were measured and compared using synthetic magnetic resonance imaging and proton density fat fraction analyses. Moreover, the factors (T2 values and fat content) associated with severe CLBP (assessed using the VAS score) were analyzed.

Results

The fat content of the right MF and ES was higher in patients with CLBP than in healthy individuals (p < 0.05). The T2 values of each LIVD in the CLBP and control groups were not significantly different (p > 0.05). Moreover, the VAS scores did not correlate with the T2 values of the patients (p > 0.05). The fat content of the bilateral MF and ES muscles was positively associated with the VAS score in young patients with CLBP (left MF: r = 0.506, p = 0.01; right MF: r = 0.532, p = 0.01; left ES: r = 0.636, p < 0.01; and right ES: r = 0.716, p < 0.01).

Conclusion

Degeneration of the MF and ES may contribute to CLBP in young patients. In addition, the severity of CLBP is positively correlated with the degree of fat infiltration in the MF and ES.

Osteopontin deficiency promotes cartilaginous endplate degeneration by enhancing the NF-κB signaling to recruit macrophages and activate the NLRP3 inflammasome

Intervertebral disc degeneration (IDD) is a major cause of discogenic pain, and is attributed to the dysfunction of nucleus pulposus, annulus fibrosus, and cartilaginous endplate (CEP). Osteopontin (OPN), a glycoprotein, is highly expressed in the CEP. However, little is known on how OPN regulates CEP homeostasis and degeneration, contributing to the pathogenesis of IDD. Here, we investigate the roles of OPN in CEP degeneration in a mouse IDD model induced by lumbar spine instability and its impact on the degeneration of endplate chondrocytes (EPCs) under pathological conditions. OPN is mainly expressed in the CEP and decreases with degeneration in mice and human patients with severe IDD. Conditional Spp1 knockout in EPCs of adult mice enhances age-related CEP degeneration and accelerates CEP remodeling during IDD. Mechanistically, OPN deficiency increases CCL2 and CCL5 production in EPCs to recruit macrophages and enhances the activation of NLRP3 inflammasome and NF-κB signaling by facilitating assembly of IRAK1-TRAF6 complex, deteriorating CEP degeneration in a spatiotemporal pattern. More importantly, pharmacological inhibition of the NF-κB/NLRP3 axis attenuates CEP degeneration in OPN-deficient IDD mice. Overall, this study highlights the importance of OPN in maintaining CEP and disc homeostasis, and proposes a promising therapeutic strategy for IDD by targeting the NF-κB/NLRP3 axis.

Association between vertebral endplate defects and patient-reported symptoms: an immunohistochemical study investigating the COX-2/PGE-2/EP-4 axis

BACKGROUND CONTEXT

Vertebral endplate defects are often implicated in degenerative disc disorders, yet their connection to patient-reported symptoms remains unclear. COX-2 and PGE-2 are known for their roles in inflammation and pain, with EP-4 receptor involvement in pain signaling. Examining their expression in vertebral endplate tissues may provide insights into pathomechanism of low back pain.

PURPOSE

To investigate the association between endplate defects and patient-reported symptoms and to further clarify the role of the COX-2/PGE-2/EP-4 axis in the pathogenesis of chronic low back pain.

STUDY DESIGN/SETTING

Retrospective study.

PATIENT SAMPLE

A total of 71 patients who had undergone single-level L4/5 or L5/S1 modified laminectomy decompression preserving proximal upper laminae and transforaminal lumbar interbody fusion surgery were included in this study, including 18 patients diagnosed with lumbar disc herniation, 19 with lumbar disc herniation accompanied by degenerative lumbar spinal stenosis, and 34 with degenerative spondylolisthesis.

OUTCOME MEASURES

Demographic data, Pfirrmann grade, Modic changes, endplate defect score, visual analog scale (VAS) for back and leg pain, and Oswestry Disability Index (ODI) before surgery, 3-month and 6-month follow-up, and the percentage of immune-positive cells (COX-2, PGE-2, and EP-4) in endplate tissue sections.

METHODS

Patients were divided into defect and nondefect groups according to endplate morphology on lumbar MR. All intraoperative endplate specimens were immediately fixed in 10% formaldehyde, and then embedded in paraffin 3 days later for tissue sections. The outcome measures were compared between the defect group and nondefect group. Data were analyzed using independent t-tests and χ² tests. Pearson's rank correlation test was used to assess correlations between patient-reported symptoms and the percentage of immune-positive cells in the groups. Multivariable logistic regression models using the forward stepwise likelihood ratio method were used to identify the factors that were independently associated with endplate defects.

RESULTS

The age of Defect group was significantly higher than that of nondefect group (52.5±7.7 vs 57.2±9.1. p=.024). There were no significant differences in gender, diagnosis, BMI, comorbidities, or surgical level between the two groups. Modic changes (Type Ⅱ/Type Ⅲ) were more common in patients of Defect group than nondefect group (38.5% vs 11.1%, p<.001), and so was disc degeneration (Pfirrmann grade Ⅳ/Ⅴ) (69.2% vs 33.3%, p<.001). Defect group had significantly higher VAS-Back (6.5±2.0 vs 4.9±1.6, p<.001) and ODI scores (62.9±10.7 vs 45.2±14.8, p<.001) than nondefect group, while there was no significant differences between the two groups during the 3 and 6-month follow-up after surgery. Histologically, Defect group was characterized by upregulation of COX-2, PGE-2, and EP-4 in endplate tissue sections. Both in defect and nondefect groups, VAS-Back showed moderate positive correlations with the expressions of COX-2 (r=0.643; r=0.558, p both<.001), PGE-2 (r=0.611; r=0.640, p both<.001), and EP-4 (r=0.643; r=0.563, p both<.001). Multivariate regression analyses reveled that percentage of COX-2-positive cells was associated with endplate defects (OR=1.509, 95%CI [1.048-2.171], p=.027), as well as percentage of PGE-2-positive (OR=1.291, 95%CI [1.106-1.508], p=.001) and EP-4-positive cells (OR=1.284, 95%CI [1.048∼2.171], p=.003).

CONCLUSIONS

Patients with endplate defects had worse quality of life, more severe disc degeneration and Modic changes, and up-regulated COX-2/PGE-2/EP-4 axis expression in cartilage endplates in patients with defected endplates. Inflammatory factors may significantly contribute to the onset and progression of chronic low back pain in patients with endplate defects, consequently impacting patient-reported symptoms.

Three Stages on Magnetic Resonance Imaging of Lumbar Degenerative Spine

PURPOSES

To propose a new lumbar degenerative staging system using the current radiological classification system.

METHODS

A cross-sectional analysis of retrospective databases between January 2018 and December 2022 was performed. Total of 410 patients for Modic changes, paravertebral muscle fat infiltration, disc degeneration, articular process degeneration, vertebral endplate degeneration and other structures, and disc displacement, Spondylolisthesis, and stenosis, and grouped patients according to stage were assessed. Visual analog scale, Japanese Orthopaedic Association, and Oswestry Disability Index scores were used to assess low back pain strength, neurological function, and quality of life, respectively.

RESULTS

The lumbar degeneration staging system consists of 8 variables, which can be divided into 3 steps: early, middle and late, and the correlation between each variable is strong (P < 0.05). The later the staging, the worse the Japanese Orthopaedic Association, visual analog scale, and Oswestry Disability Index scores.

CONCLUSIONS

Patients with later stages have worse clinical scores. This staging system recommends a uniform classification to assess lumbar degeneration.

Lumbar foraminal stenosis was associated with back pain and leg pain: epidemiological evidence from a population-based cohort

OBJECTIVES

To determine the characteristics of lumbar foraminal stenosis (LFS) on magnetic resonance (MR) images and their association with back pain and radiating leg pain in a population-based sample of Chinese subjects.

METHODS

This study was an extension of the Hangzhou Lumbar Spine Study, a cross-sectional study focusing on back pain and lumbar spine MR imaging findings. Questionnaire data, including demographics, lifestyle, occupational exposures, back pain and radiating leg pain were included. On lumbar spine MR images, disc degeneration was assessed using Pfirrmann grade and Modic changes were evaluated. Using Lee's scale, the L3-S1 intervertebral foramina were evaluated, with grade 2-3 representing substantial LFS and grade 0-1 no LFS. Characteristics of LFS were noted, and associations of LFS with back pain and radiating leg pain were examined.

RESULTS

Among the 644 study subjects, 141 (21.9%) had at least one LFS, and its occurrence was associated with greater age (OR = 1.93 for each 10 years, p < 0.001). Substantial LFS was associated with the presence of back pain (OR = 1.92, p = 0.001) and the intensity of the worst back pain (Coef = 8.30, p < 0.001) over the past 12 months, and disabling back pain during their lifetime (OR = 2.25, p < 0.001). Substantial LFS was also associated with leg pain (OR = 14.27, p < 0.001), with a sensitivity of 75.7% for the presence of radiating leg pain and a specificity of 81.4%.

CONCLUSION

Substantial LFS on MR images was a common age-related degenerative phenotype in adults, and appears to be an independent risk factor for back pain and leg pain.

Optimization of radiation doses for open lumbar spinal fusion using C-arm fluoroscopy and impact on radiation-induced cancer: a pilot study

PURPOSE

Intraoperative fluoroscopy use is essential during spinal fusion procedures. The amount of radiation dose should always be minimized. This study aimed to determine the feasibility of halving the frame rate from 12.5 to 6.25 frames per second (fps) and to quantify the reduction in the risk of developing radiation-induced cancer.

METHODS

This pilot study included 34 consecutive patients operated for open lumbar posterolateral fusion (PLF) with or without transforaminal lumbar interbody fusion (TLIF). C-arm modes were changed from half-dose (12.5 frames per second (fps), group I) to quarter-dose (6.25 fps, group II). Age, body mass index, surgical procedure, number of treated levels, and complications were collected. Kerma area product (KAP), cumulative air kerma (CAK), and fluoroscopy time were compared. Effective dose and radiation-induced cancer risk were estimated.

RESULTS

Eighteen and 16 patients were, respectively, included in group I and II. Demographic, surgical data, and fluoroscopy time were similar in both groups. However, CAK, KAP, and effective dose were significantly lower in group II, respectively, 0.56 versus 0.41 mGy (p = 0.03), 0.09 versus 0.06 Gy cm2 (p = 0.04), and 0.03 versus 0.02 mSv (p = 0.04). Radiation-induced cancer risk decreased by 47.7% from 1.49 × 10-6 to 7.77 × 10-7 after optimization. No complications were recorded in either group.

CONCLUSION

This study demonstrates the feasibility of setting 6.25 fps for TLIF with and without PLF. By halving the fps, radiation-induced cancer risk could be almost divided by two, without compromising surgical outcome. Finally, after optimization, the risk of developing radiation-induced cancer was less than one in a million.

Osteoarthritis year in review 2023: Imaging

PURPOSE

This narrative review summarizes the original research in the field of in vivo osteoarthritis (OA) imaging between 1 January 2022 and 1 April 2023.

METHODS

A PubMed search was conducted using the following several terms pertaining to OA imaging, including but not limited to "Osteoarthritis / OA", "Magnetic resonance imaging / MRI", "X-ray" "Computed tomography / CT", "artificial intelligence /AI", "deep learning", "machine learning". This review is organized by topics including the anatomical structure of interest and modality, AI, challenges of OA imaging in the context of clinical trials, and imaging biomarkers in clinical trials and interventional studies. Ex vivo and animal studies were excluded from this review.

RESULTS

Two hundred and forty-nine publications were relevant to in vivo human OA imaging. Among the articles included, the knee joint (61%) and MRI (42%) were the predominant anatomical area and imaging modalities studied. Marked heterogeneity of structural tissue damage in OA knees was reported, a finding of potential relevance to clinical trial inclusion. The use of AI continues to rise rapidly to be applied in various aspect of OA imaging research but a lack of generalizability beyond highly standardized datasets limit interpretation and wide-spread application. No pharmacologic clinical trials using imaging data as outcome measures have been published in the period of interest.

CONCLUSIONS

Recent advances in OA imaging continue to heavily weigh on the use of AI. MRI remains the most important modality with a growing role in outcome prediction and classification.

Lumbar paraspinal muscle morphology is associated with spinal degeneration in patients with lumbar spinal stenosis

BACKGROUND CONTEXT

Lumbar spinal stenosis (LSS) has been reported to induce changes in paraspinal muscle morphology, but objective physical function and degenerative spine conditions are rarely assessed.

PURPOSE

To identify factors associated with paraspinal muscle morphology using objective physical and degenerative spine assessments in patients with LSS.

STUDY DESIGN/SETTING

Cross-sectional design.

PATIENT SAMPLE

Seventy patients with neurogenic claudication caused by LSS, receiving outpatient physical therapy.

OUTCOME MEASURES

Cross-sectional area (CSA) and functional CSA (FCSA) of the multifidus, erector spinae, and psoas muscles, the severity of stenosis, disc degeneration, and endplate abnormalities were evaluated by magnetic resonance imaging, as well as sagittal spinopelvic alignment by X-ray. Objective physical assessments included pedometry and claudication distance. Patient-reported outcomes included the numerical rating scale of low back pain, leg pain, and leg numbness, and the Zurich Claudication Questionnaire.

METHODS

To assess the impact of LSS on paraspinal muscles, FCSA and FCSA/CSA were compared between the dominant and nondominant sides based on the patients' neurogenic symptoms, and multivariable regression analyses adjusted for age, sex, height, and weight were performed; p<.05 was considered significant.

RESULTS

Seventy patients were analyzed. At one level below the maximum stenotic level, erector spinae FCSA on the dominant side was significantly lower than that on the nondominant side. In the multivariable regression analyses, at one level below the symptomatic level, disc degeneration, endplate abnormalities, and lumbar spinopelvic alignment, such as decreased lumbar lordosis and increased pelvic tilt, were negatively associated with multifidus FCSA and FCSA/CSA ratio. A significant association was observed between dural sac CSA and erector spinae FCSA. Throughout L1/2 to L5/S, disc degeneration, endplate abnormalities, and lumbar spinopelvic alignment were negatively associated with multifidus and erector spinae FCSA or FCSA/CSA.

CONCLUSIONS

Lumbar paraspinal muscle asymmetry caused by LSS was observed only in erector spinae. Disc degeneration, endplate abnormalities, and lumbar spinopelvic alignment, rather than spinal stenosis and LSS symptoms, were more associated with paraspinal muscle atrophy or fat infiltration.

The association between vertebral endplate defects, subchondral bone marrow changes, and lumbar intervertebral disc degeneration: a retrospective, 3-year longitudinal study

PURPOSE

To investigate the influence of vertebral endplate defects and subchondral bone marrow changes on the development of lumbar intervertebral disc degeneration (DD).

METHODS

Patients > 18 y/o without any history of lumbar fusion who had repeat lumbar magnetic resonance imaging scans primarily for low back pain (LBP) performed at a minimum of 3 years apart at a single institution, and no spinal surgery in between scans were included. Total endplate score (TEPS), Modic changes (MC), and Pfirrmann grading (PFG) per lumbar disc level were assessed. DD was defined as PFG ≥ 4.

RESULTS

Three hundred and fifty-three patients (54.4% female) were included in the final analysis, comprising 1765 lumbar intervertebral discs. The patient population was 85.6% Caucasian with a median age of 60.1 years and a body mass index (BMI) of 25.8 kg/m2. A cutoff score of 5 was identified for the TEPS above which both the prevalence of DD and the odds of developing DD increased. The probability of developing DD did not differ significantly between lumbar disc levels (P = 0.419). In the multivariable analysis with adjustments for age, sex, race, body mass index (BMI), MC, TEPS cutoff > 5, and spinal level, only age (OR = 1.020; P = 0.002) was found to be an independent risk factor for developing intervertebral DD.

CONCLUSION

Our results suggest that TEPS does not unequivocally predict intervertebral DD in patients with LBP, since higher degrees of endplate defects might also develop secondarily to DD, and MC tend to occur late in the cascade of degeneration.

Automatic classification of the vertebral endplate lesions in magnetic resonance imaging by deep learning model

Introduction

A novel classification scheme for endplate lesions, based on T2-weighted images from magnetic resonance imaging (MRI) scan, has been recently introduced and validated. The scheme categorizes intervertebral spaces as "normal," "wavy/irregular," "notched," and "Schmorl's node." These lesions have been associated with spinal pathologies, including disc degeneration and low back pain. The exploitation of an automatic tool for the detection of the lesions would facilitate clinical practice by reducing the workload and the diagnosis time. The present work exploits a deep learning application based on convolutional neural networks to automatically classify the type of lesion.

Methods

T2-weighted MRI scans of the sagittal lumbosacral spine of consecutive patients were retrospectively collected. The middle slice of each scan was manually processed to identify the intervertebral spaces from L1L2 to L5S1, and the corresponding lesion type was labeled. A total of 1,559 gradable discs were obtained, with the following types of distribution: "normal" (567 discs), "wavy/irregular" (485), "notched" (362), and "Schmorl's node" (145). The dataset was divided randomly into a training set and a validation set while preserving the original distribution of lesion types in each set. A pretrained network for image classification was utilized, and fine-tuning was performed using the training set. The retrained net was then applied to the validation set to evaluate the overall accuracy and accuracy for each specific lesion type.

Results

The overall rate of accuracy was found equal to 88%. The accuracy for the specific lesion type was found as follows: 91% (normal), 82% (wavy/irregular), 93% (notched), and 83% (Schmorl's node).

Discussion

The results indicate that the deep learning approach achieved high accuracy for both overall classification and individual lesion types. In clinical applications, this implementation could be employed as part of an automatic detection tool for pathological conditions characterized by the presence of endplate lesions, such as spinal osteochondrosis.

Modic Changes of the Cervical and Lumbar Spine and Their Effect on Neck and Back Pain: A Systematic Review and Meta-Analysis

STUDY DESIGN

Systematic Review.

OBJECTIVES

To systematically review the current literature and perform a meta-analysis on patients with cervical or lumbar spine Modic changes to determine if their baseline axial back pain and disability are comparable to patients without Modic changes.

METHODS

A systematic review of the PubMed database was conducted in accordance with PRISMA guidelines. A meta-analysis was performed to compare the mean differences in back pain, leg pain, and disability based on the presence of cervical or lumbar spine Modic changes. A subgroup analysis of the different types of Modic changes was conducted to determine if Modic type affected back pain or disability.

RESULTS

- After review of 259 articles, 17 studies were included for meta-analysis and ten studies were included for qualitative synthesis. In the lumbar spine, 10 high-quality studies analyzed Visual Analog Scale (VAS) back pain, 10 evaluated VAS leg pain, and 8 analyzed Oswestry Disability Index. VAS back pain (mean difference (MD), -.38; 95% CI, -.61 - .16) and Oswestry disability index (MD -2.52; 95% CI, -3.93 - -1.12) were significantly lower in patients without Modic changes. Modic change subtype was not associated with differences in patient-reported outcomes. Patients with cervical spine Modic changes did not experience more severe pain than those without MC.

CONCLUSIONS

Modic changes in the lumbar spine are not associated with clinically significant axial low back pain severity or patient disability. Similar to the lumbar spine, Modic changes in the cervical spine are not associated with symptom severity, but they are associated with pain duration.

Endplate role in the degenerative disc disease: A brief review

The degenerative disease of the intervertebral disc is nowadays an important health problem, which has still not been understood and solved adequately. The vertebral endplate is regarded as one of the vital elements in the structure of the intervertebral disc. Its constituent cells, the chondrocytes in the endplate, may also be involved in the process of the intervertebral disc degeneration and their role is central both under physiological and pathological conditions. They main functions include a role in homeostasis of the extracellular environment of the intervertebral disc, metabolic support and nutrition of the discal nucleus and annulus beneath and the preservation of the extracellular matrix. Therefore, it is understandable that the cells in the endplate have been in the centre of research from several viewpoints, such as development, degeneration and growth, reparation and remodelling, as well as treatment strategies. In this article, we briefly review the importance of vertebral endplate, which are often overlooked, in the intervertebral disc degeneration.

Age-related radiographic parameters difference between the degenerative lumbar spinal stenosis patients and healthy people and correlation analysis

OBJECTIVES

To identify age-related radiographic risk factors for degenerative lumbar spinal stenosis (DLSS) and analyze correlations among them.

METHODS

A total of 180 cases were enrolled in this study, and lumbar magnetic resonance was performed. Among them, 93 cases suffered DLSS and lumbar dynamic X-ray was examined. And following parameters were measured and evaluated: intervertebral disk height (IDH), the ratio of IDH(IDH_L4-5/L3-4), initial IDH of L4-5(iIDH_L4-5) in the DLSS group, disk degeneration (DD), cartilaginous endplate failure (CEF), Modic changes, the thickness of ligamentum flavum (LF), range of intervertebral motion (ROM), facet joint opening (FJO), facet joint angle (FJA), the standard cross-sectional area (SCSA) of the multifidus, erector spinae, and psoas major muscles. The data of two groups were compared, and the possible risk factors of DLSS were analyzed.

RESULTS

Compared with the control group, the DLSS group had higher IDH except for L4-5 and larger iIDH_L4-5 (P < 0.05). Significant differences were shown in CEF and the thickness of LF at L1-S1 and DD at L4-5 (P < 0.05). The DLSS group had smaller SCSA of multifidus, erector spinae, and psoas major muscles but greater FJA, FJO (P < 0.05). And the risk of DLSS increased when iIDH_L4-5 ≥ 10.73 mm, FJA ≥ 52.03° , or FJO ≥ 3.75 mm. IDH positively correlated with SCSA of multifidus and psoas major muscles and ROM at L1-S1 (P < 0.05). DD showed negative linear relations with SCSA of multifidus and psoas muscle and positive linear relation with CEF at L1-2, L2-3, and L5-S1 (P < 0.05).

CONCLUSION

Larger initial disk height and excessive CEF may induce DLSS by increasing intervertebral mobility to promote DD, and atrophied paravertebral muscles by weakening the stability of lumbar spine.

MRI grading of spinal stenosis is not associated with the severity of low back pain in patients with lumbar spinal stenosis

Background

Although lumbar spinal stenosis (LSS) often coexists with other degenerative conditions, few studies have fully assessed possible contributing factors for low back pain (LBP) in patients with LSS. The purpose of this study was to identify factors associated with the severity of LBP in patients with LSS.

Methods

The patients with neurogenic claudication caused by LSS, which was confirmed by magnetic resonance imaging (MRI) were included in this cross-sectional study. Data included ratings of LBP, buttock and leg pain, and numbness on a numerical rating scale (NRS), 36-item Short-Form Survey (SF-36) scores, muscle mass measured by bioelectrical impedance analysis, and radiographic measurements including lumbopelvic alignment and slippage. The severity of LSS, endplate defects, Modic endplate changes, intervertebral disc degeneration, and facet joint osteoarthritis were evaluated on MRI. Spearman correlation and multivariate linear regression analyses were used to examine the factors associated with the severity of LBP (NRS score).

Results

A total of 293 patients (135 male and 158 female, average age 72.6 years) were analyzed. LBP was moderately correlated with buttock and leg pain, and buttock and leg numbness. Significant but weak correlations were observed between LBP and body mass index, appendicular and trunk muscle mass, all domains of SF-36, pelvic tilt, total number of endplate defects and Modic endplate changes, and summary score of disc degeneration grading, but not severity or number of spinal stenoses. In the multivariate regression analysis, age, female sex, trunk muscle mass, diabetes, NRS buttock and leg pain, NRS buttock and leg numbness, SF-36 vitality, pelvic tilt, and total number of endplate defects were associated with the severity of LBP.

Conclusions

Trunk muscle mass, lumbopelvic alignment, and endplate defects, but not severity of stenosis are partly associated with severity of LBP, but buttock and leg pain and buttock and leg numbness have strongest relationships with LBP in patients with LSS.