Prevalence and pattern of lumbar magnetic resonance imaging changes in a population study of one thousand forty-three individuals

The profile of the spinal column in subjects with lumbar developmental spinal stenosis

AIMS

The aim of this study was to determine the differences in spinal imaging characteristics between subjects with or without lumbar developmental spinal stenosis (DSS) in a population-based cohort.

METHODS

This was a radiological analysis of 2,387 participants who underwent L1-S1 MRI. Means and ranges were calculated for age, sex, BMI, and MRI measurements. Anteroposterior (AP) vertebral canal diameters were used to differentiate those with DSS from controls. Other imaging parameters included vertebral body dimensions, spinal canal dimensions, disc degeneration scores, and facet joint orientation. Mann-Whitney U and chi-squared tests were conducted to search for measurement differences between those with DSS and controls. In order to identify possible associations between DSS and MRI parameters, those who were statistically significant in the univariate binary logistic regression were included in a multivariate stepwise logistic regression after adjusting for demographics. Odds ratios (ORs) and 95% confidence intervals (CIs) were reported where appropriate.

RESULTS

Axial AP vertebral canal diameter (p < 0.001), interpedicular distance (p < 0.001), AP dural sac diameter (p < 0.001), lamina angle (p < 0.001), and sagittal mid-vertebral body height (p < 0.001) were significantly different between those identified as having DSS and controls. Narrower interpedicular distance (OR 0.745 (95% CI 0.618 to 0.900); p = 0.002) and AP dural sac diameter (OR 0.506 (95% CI 0.400 to 0.641); p < 0.001) were associated with DSS. Lamina angle (OR 1.127 (95% CI 1.045 to 1.214); p = 0.002) and right facet joint angulation (OR 0.022 (95% CI 0.002 to 0.247); p = 0.002) were also associated with DSS. No association was observed between disc parameters and DSS.

CONCLUSION

From this large-scale cohort, the canal size is found to be independent of body stature. Other than spinal canal dimensions, abnormal orientations of lamina angle and facet joint angulation may also be a result of developmental variations, leading to increased likelihood of DSS. Other skeletal parameters are spared. There was no relationship between DSS and soft tissue changes of the spinal column, which suggests that DSS is a unique result of bony maldevelopment. These findings require validation in other ethnicities and populations. Level of Evidence: I (diagnostic study) Cite this article: Bone Joint J 2021;103-B(4):725-733.

Predicting Spinal Surgery Candidacy From Imaging Data Using Machine Learning

BACKGROUND

The referral process for consultation with a spine surgeon remains inefficient, given a substantial proportion of referrals to spine surgeons are nonoperative.

OBJECTIVE

To develop a machine-learning-based algorithm which accurately identifies patients as candidates for consultation with a spine surgeon, using only magnetic resonance imaging (MRI).

METHODS

We trained a deep U-Net machine learning model to delineate spinal canals on axial slices of 100 normal lumbar MRI scans which were previously delineated by expert radiologists and neurosurgeons. We then tested the model against lumbar MRI scans for 140 patients who had undergone lumbar spine MRI at our institution (60 of whom ultimately underwent surgery, and 80 of whom did not). The model generated automated segmentations of the lumbar spinal canals and calculated a maximum degree of spinal stenosis for each patient, which served as our biomarker for surgical pathology warranting expert consultation.

RESULTS

The machine learning model correctly predicted surgical candidacy (ie, whether patients ultimately underwent lumbar spinal decompression) with high accuracy (area under the curve = 0.88), using only imaging data from lumbar MRI scans.

CONCLUSION

Automated interpretation of lumbar MRI scans was sufficient to correctly determine surgical candidacy in nearly 90% of cases. Given that a significant proportion of referrals placed for spine surgery evaluation fail to meet criteria for surgical intervention, our model could serve as a valuable tool for patient triage and thereby address some of the inefficiencies within the outpatient surgical referral process.

Understanding the impact of lumbar disc degeneration and chronic low back pain: A cross-sectional electromyographic analysis of postural strategy during predicted and unpredicted postural perturbations

People with chronic low back pain (LBP) exhibit changes in postural control. Stereotypical muscle activations resulting from external perturbations include anticipatory (APAs) and compensatory (CPAs) postural adjustments. The aim and objective of this study was to determine differences in postural control strategies (peak amplitude, APAs and CPAs) between symptomatic and asymptomatic adults with and without Lumbar Disc Degeneration (LDD) using surface electromyography during forward postural perturbation. Ninety-seven subjects participated in the study (mean age 50 years (SD 12)). 3T MRI was used to acquire T2 weighted images (L1-S1). LDD was determined using Pfirrmann grading. A bespoke translational platform was designed to deliver horizontal perturbations in sagittal and frontal planes. Electromyographic activity was analysed bilaterally from 8 trunk and lower limb muscles during four established APA and CPA epochs. A Kruskal-Wallis H test with Bonferroni correction for multiple comparisons was conducted. Four groups were identified: no LDD no pain (n = 19), LDD no pain (n = 38), LDD pain (n = 35) and no LDD pain (n = 5). There were no significant differences in age or gender between groups. The most significant difference between groups was observed during forward perturbation. In the APA and CPA phases of predictable forward perturbation there were significant differences ankle strategy between groups (p = 0.007–0.008); lateral gastrocnemius and tibialis anterior activity was higher in the LDD pain than the LDD no pain group. There were no significant differences in the unpredictable condition (p>0.05). These findings were different from the remaining groups, where significant differences in hip strategy were observed during both perturbation conditions (p = 0.004–0.006). Symptomatic LDD patients exhibit different electromyographic strategies to asymptomatic LDD controls. Future LBP electromyographic research should benefit from considering assessment of both lower limbs in addition to the spine. This approach could prevent underestimation of postural control deficits and guide targeted rehabilitation.

The Application of Mesenchymal Stromal Cells and Their Homing Capabilities to Regenerate the Intervertebral Disc

Chronic low back pain (LBP) remains a challenging condition to treat, and especially to cure. If conservative treatment approaches fail, the current “gold standard” for intervertebral disc degeneration (IDD)-provoked back pain is spinal fusion. However, due to its invasive and destructive nature, the focus of orthopedic research related to the intervertebral disc (IVD) has shifted more towards cell-based therapeutic approaches. They aim to reduce or even reverse the degenerative cascade by mimicking the human body’s physiological healing system. The implementation of progenitor and/or stem cells and, in particular, the delivery of mesenchymal stromal cells (MSCs) has revealed significant potential to cure the degenerated/injured IVD. Over the past decade, many research groups have invested efforts to find ways to utilize these cells as efficiently and sustainably as possible. This narrative literature review presents a summary of achievements made with the application of MSCs for the regeneration of the IVD in recent years, including their preclinical and clinical applications. Moreover, this review presents state-of-the-art strategies on how the homing capabilities of MSCs can be utilized to repair damaged or degenerated IVDs, as well as their current limitations and future perspectives.

Orthopaedic Practices and Surgeries during COVID-19 in Pakistan - A Survey Based Study

Introduction:

The study aimed to target the current practices of the orthopaedic community in outpatient (OPD), emergency (ER) and surgical services (OT) during COVID-19.

Material and method:

This study surveyed 303 orthopaedic surgeons from all over Pakistan. The survey had 30 questions targeting the setup of outpatient, emergency and operation services in orthopaedic departments of different hospitals in Pakistan.

Result:

A total of 302 surgeons were included from 53 cities all over Pakistan. Between 35-48% of the respondents reported lack of availability of standard operating procedures in OPD, ER and in OT. Majority of the respondents noted that their OPD and surgical practice had been affected to some degree and 69% of the surgeons were only doing trauma surgery. This trend was higher in younger consultants of less than 45 years of age (p<0.001). Almost two-third of the surgeons, mostly senior (p=0.03) were using surgical masks as the only protective measure during various practices of OPD, ER and OT, while most of the setups were not assessing patients even for signs and symptoms of COVID. Almost 89% of the orthopaedic community is facing definite to mild stress during this pandemic and this has significantly affected the senior surgeons (p=0.01).

Conclusion:

Our study highlighted that COVID-19 has resulted in marked changes to the practices of the majority of Pakistani orthopaedic surgeons. Despite a sharp upsurge in the number of cases and mortality due to COVID-19, guidelines were still lacking at most of the settings and a substantial percentage of the orthopaedic community were not following adequate safety measures while attending to patients.

The anterior and traverse cage can provide optimal biomechanical performance for both traditional and percutaneous endoscopic transforaminal lumbar interbody fusion

BACKGROUND

Transforaminal lumbar interbody fusion (TLIF) is a well-established surgical treatment for patients with lumbar degenerative disc disease; however, the optimal position for the interbody fusion cage in TLIF procedures for reducing cage-related complications remains uncertain. The present study aims to compare the biomechanical effects between different cage positions in TLIF and percutaneous endoscopic-TLIF (PE-TLIF).

METHOD

An intact finite element model of L3-L5 from computed tomography images of a 25-year-old healthy male without any lumbar disease was reconstructed and validated. TLIF and PE-TLIF were performed on L4-L5 with bilateral pedicle screws fixation. Two surgical finite element models were subjected to loads with six degrees of freedom. The range of motion (ROM) and von Mises stress of the implantations and endplates were measured for the anterior, middle, and posterior district and the traverse or oblique direction of the cage respectively.

RESULTS

As the cage was implanted forward, the ROMs in the fused L4-L5 segments and the von Mises stress of the cage and endplates decreased while the von Mises stress of the screws increased; this was also shown in the traverse cage when compared with the oblique cage (A-90-compared with A-45- had a 31.3%, 1.7%, 12.6%, and 5.7% decrease in FL, EX, LB and AR). The ROMs (TLIF A-45 increase of 80.8%, 23.8%, and 12.2% in FL, EX, and LB when compared with PE-TLIF), cage stress, and endplate stress of PE-TLIF were lower than those of TLIF.

CONCLUSIONS

Considering the ROM of the fusion segments, implanting the cage in the anterior district in the traverse direction can effectively enhance the fusion segment stiffness, thus contributing to the stability of the lumbar spine after fusion. It can also cause less cage stress and endplate stress, which indicates its beneficial effect in avoiding cage injury or subsidence. However, the higher stress of the pedicle screws and rods indicates higher failure risk. PE-TLIF had better biomechanical performance than TLIF. Therefore, it is recommended that the surgeon implant the cage in the anterior district of the L5 vertebra's upper endplate in the traverse direction using the PE-TLIF technique.

Painful intervertebral disc degeneration and inflammation: from laboratory evidence to clinical interventions

Low back pain (LBP), as a leading cause of disability, is a common musculoskeletal disorder that results in major social and economic burdens. Recent research has identified inflammation and related signaling pathways as important factors in the onset and progression of disc degeneration, a significant contributor to LBP. Inflammatory mediators also play an indispensable role in discogenic LBP. The suppression of LBP is a primary goal of clinical practice but has not received enough attention in disc research studies. Here, an overview of the advances in inflammation-related pain in disc degeneration is provided, with a discussion on the role of inflammation in IVD degeneration and pain induction. Puncture models, mechanical models, and spontaneous models as the main animal models to study painful disc degeneration are discussed, and the underlying signaling pathways are summarized. Furthermore, potential drug candidates, either under laboratory investigation or undergoing clinical trials, to suppress discogenic LBP by eliminating inflammation are explored. We hope to attract more research interest to address inflammation and pain in IDD and contribute to promoting more translational research.

A New Hope in Spinal Degenerative Diseases: Piezo1

As a newly discovered mechanosensitive ion channel protein, the piezo1 protein participates in the transmission of mechanical signals on the cell membrane and plays a vital role in mammalian biomechanics. Piezo1 has attracted widespread attention since it was discovered in 2010. In recent years, studies on piezo1 have gradually increased and deepened. In addition to the discovery that piezo1 is expressed in the respiratory, cardiovascular, gastrointestinal, and urinary systems, it is also stably expressed in cells such as mesenchymal stem cells (MSCs), osteoblasts, osteoclasts, chondrocytes, and nucleus pulposus cells that constitute vertebral bodies and intervertebral discs. They can all receive external mechanical stimulation through the piezo1 protein channel to affect cell proliferation, differentiation, migration, and apoptosis to promote the occurrence and development of lumbar degenerative diseases. Through reviewing the relevant literature of piezo1 in the abovementioned cells, this paper discusses the effect of piezo1 protein expression under mechanical stress stimuli on spinal degenerative disease, providing the molecular basis for the pathological mechanism of spinal degenerative disease and also a new basis, ideas, and methods for the prevention and treatment of this degenerative disease.

The Role of Panx3 in Age-Associated and Injury-Induced Intervertebral Disc Degeneration

Pannexin 3 (Panx3) is a mechanosensitive, channel-forming glycoprotein implicated in the progression of post-traumatic osteoarthritis. Despite evidence for Panx3 expression in the intervertebral disc (IVD), its function in this cartilaginous joint structure remained unknown. Using Panx3 knockout mice, this study investigated the role of Panx3 in age-associated IVD degeneration and degeneration induced by annulus fibrosus (AF) needle puncture. Loss of Panx3 did not significantly impact the progression of age-associated histopathological IVD degeneration; however, loss of Panx3 was associated with decreased gene expression of Acan, Col1a1, Mmp13 and Runx2 and altered localization of COLX in the IVD at 19 months-of-age. Following IVD injury in the caudal spine, histological analysis of wild-type mice revealed clusters of hypertrophic cells in the AF associated with increased pericellular proteoglycan accumulation, disruptions in lamellar organization and increased lamellar thickness. In Panx3 knockout mice, hypertrophic AF cells were rarely detected and AF structure was largely preserved post-injury. Interestingly, uninjured IVDs adjacent to the site of injury more frequently showed evidence of early nucleus pulposus degeneration in Panx3 knockout mice but remained healthy in wild-type mice. These findings suggest a role for Panx3 in mediating the adaptive cellular responses to altered mechanical stress in the IVD, which may buffer aberrant loads transferred to adjacent motion segments.

Clinical implications of lumbar developmental spinal stenosis on back pain, radicular leg pain, and disability

AIMS

To study the associations of lumbar developmental spinal stenosis (DSS) with low back pain (LBP), radicular leg pain, and disability.

METHODS

This was a cross-sectional study of 2,206 subjects along with L1-S1 axial and sagittal MRI. Clinical and radiological information regarding their demographics, workload, smoking habits, anteroposterior (AP) vertebral canal diameter, spondylolisthesis, and MRI changes were evaluated. Mann-Whitney U tests and chi-squared tests were conducted to search for differences between subjects with and without DSS. Associations of LBP and radicular pain reported within one month (30 days) and one year (365 days) of the MRI, with clinical and radiological information, were also investigated by utilizing univariate and multivariate logistic regressions.

RESULTS

Subjects with DSS had higher prevalence of radicular leg pain, more pain-related disability, and lower quality of life (all p < 0.05). Subjects with DSS had 1.5 (95% confidence interval (CI) 1.0 to 2.1; p = 0.027) and 1.8 (95% CI 1.3 to 2.6; p = 0.001) times higher odds of having radicular leg pain in the past month and the past year, respectively. However, DSS was not associated with LBP. Although, subjects with a spondylolisthesis had 1.7 (95% CI 1.1 to 2.5; p = 0.011) and 2.0 (95% CI 1.2 to 3.2; p = 0.008) times greater odds to experience LBP in the past month and the past year, respectively.

CONCLUSION

This large-scale study identified DSS as a risk factor of acute and chronic radicular leg pain. DSS was seen in 6.9% of the study cohort and these patients had narrower spinal canals. Subjects with DSS had earlier onset of symptoms, more severe radicular leg pain, which lasted for longer and were more likely to have worse disability and poorer quality of life. In these patients there is an increased likelihood of nerve root compression due to a pre-existing narrowed canal, which is important when planning surgery as patients are likely to require multi-level decompression surgery. Cite this article: Bone Joint J 2021;103-B(1):131-140.

Increased prevalence of pelvic venous congestion sign on sacroiliac MRI in women with clinically suspected sacroiliitis

OBJECTIVE:

To compare the prevalence of pelvic venous congestion (PVC) sign on sacroiliac and hip MRI in women of reproductive age as a possible cause of pain mimicking sacroiliitis.

METHODS:

This retrospective study included 727 MRI examinations (401 sacroiliac joint MRI and 326 hip joint MRI) that were performed between January 2010 and December 2017. Images were evaluated for the presence of sacroiliitis, presence of PVC sign and presence of other incidental findings of musculoskeletal and genitourinary disorders. After removing patients with other musculoskeletal and genitourinary disorders that may cause pain (n=188), remaining 539 (322 sacroiliac and 217 hip), MRI examinations were re-analyzed for the presence of PVC sign.

RESULTS:

Four hundred one patients with sacroiliac MRI examination had 120 (29.9%) PVC sign and 326 patients with hip MRI examinations had 54 (16.6%) PVC sign (p<0.001). After removing patients with other musculoskeletal and genitourinary disorders that may cause pain, 322 patients with sacroiliac MRI had 102 (31.7%) PVC sign and 217 patients with hip MRI examinations had 38 (17.5%) PVC sign (p<0.001). No significant difference was found between patients with acute sacroiliitis and patients without acute sacroiliitis concerning PVC prevalence (p>0.05). There were also no significant differences between other comparable incidental findings.

CONCLUSION:

Significantly increased PVC prevalence in sacroiliac MRI exams may be attributable to PCS simulating clinical sacroiliitis.

Accurate prediction of lumbar microdecompression level with an automated MRI grading system

OBJECTIVE

Lumbar spine MRI interpretations have high variability reducing utility for surgical planning. This study evaluated a convolutional neural network (CNN) framework that generates automated MRI grading for its ability to predict the level that was surgically decompressed.

MATERIALS AND METHODS

Patients who had single-level decompression were retrospectively evaluated. Sagittal T2 images were processed by a CNN (SpineNet), which provided grading for the following: central canal stenosis, disc narrowing, disc degeneration, spondylolisthesis, upper/lower endplate morphologic changes, and upper/lower marrow changes. The grades were used to calculate an aggregate score. The variables and the aggregate score were analyzed for their ability to predict the surgical level. For each surgical level subgroup, the surgical level aggregate scores were compared with the non-surgical levels.

RESULTS

A total of 141 patients met the inclusion criteria (82 women, 59 men; mean age 64 years; age range 28-89 years). SpineNet did not identify central canal stenosis in 32 patients. Of the remaining 109, 96 (88%) patients had a decompression at the level of greatest stenosis. The higher stenotic grade was present only at the surgical level in 82/96 (85%) patients. The level with the highest aggregate score matched the surgical level in 103/141 (73%) patients and was unique to the surgical level in 91/103 (88%) patients. Overall, the highest aggregate score identified the surgical level in 91/141 (65%) patients. The aggregate MRI score mean was significantly higher for the L3-S1 surgical levels.

CONCLUSION

A previously developed CNN framework accurately predicts the level of microdecompression for degenerative spinal stenosis in most patients.

Patterns of Lumbar Disc Degeneration: Magnetic Resonance Imaging Analysis in Symptomatic Subjects

Study Design

Cross-sectional study.

Purpose

To evaluate lumbar disc degeneration (LDD) on magnetic resonance imaging (MRI) in symptomatic subjects to accumulate baseline data on the pattern of degeneration.

Overview of Literature

LDD plays an important role in the diagnosis and treatment of low-back pain in patients. Few studies have focused on the pattern of LDD to understand how the lumbar spine ages.

Methods

This study included 1,095 patients (mean age, 44.29 years; range, 16-85 years) who underwent upright lumbar MRI. LDD was graded into five categories (I-V). Positive LDD was defined as grade III or greater. The prevalence and pattern of LDD were analyzed, and the correlations between age and total grade of LDD were evaluated.

Results

The average number of LDD levels and the total grade of LDD increased with age. LDD moved cephalad with age. The rate of LDD increased rapidly during the decade before the prevalence of LDD and became >50%. In the single-level LDD group, the levels L5-S1 were the most common levels (60.3%). In the two-level group, L4-L5 and L5-S1 were the most common levels (53.5%). In the three-level group, L3-L4, L4-L5, and L5-S1 were the most common levels (55.7%). In the multilevel LDD group, contiguous multilevel disc degeneration (CMDD) was more common than the skipped level disc degeneration (SLDD). The levels L4-L5 were the most common levels in the CMDD group, and L5-S1 were the most common levels among SLDD.

Conclusions

LDD was found to correlate with age, and the specific patterns and rates of LDD depended on lumbar disc level and age. These LDD pattern data can be used before spinal procedures to predict the probability of natural LDD progression with age.

The miR-623/CXCL12 axis inhibits LPS-induced nucleus pulposus cell apoptosis and senescence

Nucleus pulposus cell (NPC) is the major cell type maintaining the physiological function of intervertebral discs by producing extracellular matrix (ECM). NPC apoptosis and senescence together contribute to NPC loss, finally leading to intervertebral disc degeneration (IDD). Herein, miR-623 showed to be downregulated within IDD tissue samples according to both bioinformatics and experimental analyses. In LPS-injured NPCs, miR-623 overexpression promoted LPS-suppressed cell proliferation; moreover, miR-623 overexpression inhibited cell apoptosis and senescence, increased ECM secretion, and reduced levels of inflammatory factors. In contrast to miR-623, CXCL12 expression was significantly upregulated in IDD tissues; miR-623 directly bound CXCL12 to inhibit its expression. In LPS-stimulated NPCs, CXCL12 silencing also LPS-induced changes in cell proliferation, cell senescence, ECM secretion, and inflammatory factor levels. More importantly, CXCL12 overexpression aggravated LPS-induced changes and significantly reversed the protective effects of miR-623 overexpression. In conclusion, the miR-623/CXCL12 axis could affect NPC apoptosis and senescence, ECM deposition, and inflammatory factor levels under LPS stimulation in vitro. The p65 signaling might be involved.

Proteomic analysis reveals critical molecular mechanisms involved in the macrophage anti-spinal tuberculosis process

Tuberculosis infection activates the autoimmune system. However, the role of host-pathogen interactions involved in Mycobacterium tuberculosis infection is unclear. In this study, we analyzed 6 spinal tuberculosis tissues and 6 herniated disc tissues by using liquid chromatography-tandem mass spectrometry coupled with tandem mass spectrometry, and immunohistochemical staining was performed for validating the results. We identified 42 differential immune-related proteins and 3 hub genes that are primarily localised in the tertiary granule and involved in biological processes such as cellular response to the presence of cadmium ions, regulation of ion transmembrane transport, transmembrane transport, and inflammatory responses. Genes encoding cytochrome B-245 beta chain (CYBB), matrix metallopeptidase 9 (MMP9), and C-X-C motif chemokine ligand 10 (CXCL10) were identified as the hub genes that exhibited anti-tuberculosis activity and were responsible for macrophage resistance against M. tuberculosis. In conclusion, CYBB, MMP9, and CXCL10 resist M. tuberculosis infection through chemotaxis and macrophage activation. Our results indicate that CYBB, MMP9, and CXCL10 could be considered as molecular targets for spinal tuberculosis treatment, which may significantly improve patients' quality of life and prognosis.

LncRNA FAM83H-AS1 maintains intervertebral disc tissue homeostasis and attenuates inflammation-related pain via promoting nucleus pulposus cell growth through miR-22-3p inhibition

Background

Intervertebral disc degeneration (IVDD) is regarded as the leading cause of low back pain, resulting in disability and a heavy burden on public health. Several studies have unveiled that long noncoding RNAs (lncRNAs) play a key role in the pathogenesis and progression of IVDD. In this study, we aimed to investigate the biological function and latent molecular mechanism of the lncRNA FAM83H antisense RNA 1 (FAM83H-AS1) in IVDD development.

Methods

Firstly, we established an IVDD model in rats using advanced glycation end products (AGEs) intradiscal injection. Subsequently, gain-of-function assays were conducted to investigate the role of FAM83H-AS1 in the progression of IVDD. Bioinformatics analysis, RNA pull down assay and rescue experiments were employed to shed light on the molecular mechanism underlying FAM83H-AS1 involving in IVDD.

Results

Our findings verified that AGEs treatment aggravated IVDD damage, and FAM83H-AS1 was downregulated in the IVDD group. Additionally, overexpression of FAM83H-AS1 contributed to the growth of nucleus pulposus (NP) cells and ameliorated IVDD injury. It was revealed that FAM83H-AS1 possessed the speculated binding sites of miR-22-3p. More importantly, we confirmed that FAM83H-AS1 functioned as a sponge of miR-22-3p in IVDD. Lastly, we demonstrated that miR-22-3p mediated the impact of FAM83H-AS1 on cell proliferation, ECM degradation, and inflammation.

Conclusions

Our study indicated that FAM83H-AS1 relieved IVDD deterioration through sponging miR-22-3p, and provides novel insights into the mechanisms underlying FAM83H-AS1 in IVDD progression.

Minimally Invasive Versus Open Surgery for Degenerative Spine Disorders for Elderly Patients: Experiences from a Single Institution

BACKGROUND

Minimally invasive surgery (MIS) of the spine has been associated with lower complication rates and improved patient-reported outcomes in recent studies. In this study, we aimed to investigate operative and postoperative outcomes associated with both surgical techniques in elderly patients.

METHODS

Patients who are 65 years old or older underwent either minimally invasive or open surgery for lumbar degenerative conditions. Patients with a nondegenerative cause such as infection or trauma were excluded from the analysis. Patient characteristics such as demographics and associated comorbidities as well as perioperative and postoperative complications were collected. Outcomes of interest were operative time, estimated blood loss (EBL), length of stay (LOS), readmissions, reoperations, and any complications.

RESULTS

A total of 107 elderly patients were identified for this study, with a median age of 73.0 years. Demographics and comorbidities in both groups were similar in both groups. Univariate analysis yielded an MIS group with significantly lower EBL (P < 0.001), operative time (P < 0.001), and LOS (P < 0.001). In multivariable analysis, EBL and LOS were found to be significantly lower in the MIS group (P = 0.02 and 0.001, respectively). Rates of complications, readmissions (no readmissions in MIS group), reoperations, and pain improvement also favored the MIS group and although they were not found to be significantly different between the 2 groups on univariate and multivariable analysis, the results trended toward significance.

CONCLUSIONS

These findings suggest that minimally invasive spine surgery in the elderly is safe and may pose a lower risk of associated perioperative and postoperative complications with faster recovery time.

Biomechanical role of osteoporosis in the vibration characteristics of human spine after lumbar interbody fusion

Lumbar vertebrae osteoporosis is the most common challenge for lumbar interbody fusion, and this challenge has been widely concerned by scholars for many years. However, under whole-body vibration, osteoporosis how to affect the vibration characteristics of the fusion lumbar spine, complications, and fusion outcomes is urgent to know. The L1-L5 finite element model of lumbar spine was modified to simulate the transforaminal lumbar interbody fusion model with the bilateral pedicle screw fixator at L4-L5 level. A 5 Hz, 40 N sinusoidal vertical load supplemented with a 400 N preload was used to simulate the vertical vibration of human body. The results showed that under whole-body vibration, osteoporosis of fused vertebrae may cause the adjacent segments more unstable and increase the risk of adjacent segment diseases, subsidence, cage failure, rod failure, and lumbar instability. Osteoporosis of the fused vertebrae may cause the vertebral cells an unstable, inhibited growth and lead to poorer fusion outcomes. The findings may assist us in understanding the effect of osteoporosis on the vibration characteristics of lumbar spine fusion and provide references to clinical treatments for lumbar interbody fusion and lumbar vertebrae osteoporosis.

Could compression and traction loading improve the ability of magnetic resonance imaging to identify findings related to low back pain?

BACKGROUND

Diagnostic imaging is routinely used to depict structural abnormalities in people with low back pain (LBP), but most findings are prevalent in people with and without LBP. It has been suggested that LBP is related to changes induced in the spine due to loading. Therefore, new imaging measurements are needed to improve our ability to identify structures relating to LBP.

OBJECTIVES

To investigate the response of the lumbar spine to compression and traction in participants with and without chronic LBP using MRI T₂-mapping.

METHOD

Fifteen participants with chronic LBP were matched for age, weight, and gender with 15 healthy volunteers. All participants underwent MRI under three loading conditions maintained for 20 min each: resting supine, followed by compression and traction, both using 50% body weight. Participants were imaged in the last 5 min of each loading condition. Disc morphometric and fluid-based measurements from T₂-maps were obtained.

RESULTS

Traditional MRI measurements (i.e. disc height, width and mean signal intensity) were not able to capture any differences in the changes measured in response to loading between individuals with and without pain. The location of the T₂ weighted centroid (WC) was able to capture the difference between groups in response to compression in the horizontal (p < 0.01) and vertical direction (p < 0.01), and in response to traction in the vertical direction (p < 0.01). While the location of T₂WC moved anteriorly (Effect Size (ES): 0.44) and inferiorly with compression in those with pain (ES: 0.34), it moved posteriorly (ES: -0.14) and superiorly (ES: -0.05) in the group without pain. In response to traction, the vertical location of T₂WC moved superiorly in both groups but the change was larger in those with pain (ES _Pain = -0.52; ES _{No Pain}: -0.13).

CONCLUSION

The novel measurements of the location of the T₂WC in the intervertebral discs were the only measurements capturing differences in response to loading between those with and without low back pain.

In vitro model of distinct catabolic and inflammatory response patterns of endothelial cells to intervertebral disc cell degeneration

To evaluate dominant cell-to-cell paracrine interactions, including those of human annulus fibrosus (AF), nucleus pulposus (NP), and endothelial cells (ECs), in the production of inflammatory mediators and catabolic enzymes, ECs was cultured in soluble factors derived from AF or NP cells (AFCM or NPCM, respectively) and vice versa. We analysed IL-6 and -8, vascular endothelial growth factor (VEGF), matrix metalloproteinase (MMP)-1 and -3, nerve growth factor (NGF)-β, and brain-derived neurotrophic factors (BDNFs) with qRT-PCR and ELISA. We implement a microfluidic platform to analyse migration properties of AF and NP cells and ECs in 3D cultures. Our results show that IL-1β-stimulated AF cells produced significantly higher levels of IL-6 and -8, VEGF, and MMP-1 than IL-1β-stimulated NP cells. However, production of IL-6 and -8, VEGF, and MMP-3 was significantly higher in NP cells than in AF cells, under the presence of ECs conditioned medium. We observed considerable migration of NP cells co-cultured with ECs through the microfluidic platform. These results suggest that AF cells may play a major role in the initial degeneration of intervertebral disc. Furthermore, it was found that interactions between NP cells and ECs may play a significant role in the development or progression of diseases.

The Potential Role of Hepatocyte Growth Factor in Degenerative Disorders of the Synovial Joint and Spine

This paper aims to provide a comprehensive review of the changing role of hepatocyte growth factor (HGF) signaling in the healthy and diseased synovial joint and spine. HGF is a multifunctional growth factor that, like its specific receptor c-Met, is widely expressed in several bone and joint tissues. HGF has profound effects on cell survival and proliferation, matrix metabolism, inflammatory response, and neurotrophic action. HGF plays an important role in normal bone and cartilage turnover. Changes in HGF/c-Met have also been linked to pathophysiological changes in degenerative joint diseases, such as osteoarthritis (OA) and intervertebral disc degeneration (IDD). A therapeutic role of HGF has been proposed in the regeneration of osteoarticular tissues. HGF also influences bone remodeling and peripheral nerve activity. Studies aimed at elucidating the changing role of HGF/c-Met signaling in OA and IDD at different pathophysiological stages, and their specific molecular mechanisms are needed. Such studies will contribute to safe and effective HGF/c-Met signaling-based treatments for OA and IDD.

Targeting miR-10a-5p/IL-6R axis for reducing IL-6-induced cartilage cell ferroptosis

BACKGROUND

Intervertebral disc degeneration (IDD) causes lower back pain, and is often accompanied with robust inflammation. However, whether inflammation plays a role in IDD remains controversial, and the mechanism is ill-elucidated.

METHODS

Cartilage specimens from patients with scoliosis (control) and IDD were examined for IL-6 and its receptor expression by qPCR and western blot. Primary human articular chondrocyte was employed as a model for in vitro assessment of IL-6 effects in cell viability, cellular oxidative stress and iron homeostasis by MTT, MDA, ROS and Iron Colorimetric assays. The underlying mechanism was explored by qPCR, western blot, RIP in combination with bioinformatics analysis.

RESULTS

We found in this study that IL-6 and its receptor were aberrantly expressed in cartilage tissues of IDD patients. IL-6 down-regulated miR-10a-5p, which subsequently derepressed IL-6R expression. IL-6 exposure caused cartilage cell ferroptosis by inducing cellular oxidative stress and disturbing iron homeostasis. Overexpressing miR-10a-5p suppressed IL-6R expression, and partially abolished IL-6-induced ferroptosis.

CONCLUSION

Results from current study suggests that inflammatory cytokine IL-6 appeared in IVD aggravates its degeneration by inducing cartilage cell ferroptosis. This is caused partially by inhibiting miR-10a-5p and subsequently derepressing IL-6R signaling pathway. Our study provides a novel mechanism explaining inflammatory cytokine-caused cartilage cell death in degenerative IVD, and makes IL-6/miR-10a-5p/IL-6R axis a potential therapeutic target for intervention of IDD.

Are Modic Changes Associated With Health-related Quality of Life After Discectomy: A Study on 620 Patients With Two-year Follow-up

STUDY DESIGN

A registry-based comparative cohort study with 2-year follow-up.

OBJECTIVE

To assess whether Modic changes (MCs) are associated with health-related quality of life, long-term physical disability, back- or leg pain after discectomy.

SUMMARY OF BACKGROUND DATA

Previous studies have failed to show a clinically significant association between MCs and patient-reported outcomes (PROs) after discectomy.

METHODS

Data from the Danish National Spine Registry on patients undergoing first-time lumbar discectomy at a single institution from 2014 to 2017 with an accessible preoperative lumbar magnetic resonance imaging, complete preoperative, and 2-year follow-up questionnaires were obtained. PROs including Oswestry disability index (ODI), European Quality of Life-Five Dimensions (EQ-5D), visual analogue scale (VAS) back and leg pain, and patient satisfaction were collected. Patients were stratified based on the presence (+MC) or absence (-MC) of MCs on the preoperative MRI.

RESULTS

Of 620 patients included, MCs were present in 290 patients (47%). Of these, MC type 1 (MC-1) was present in 73 (25%) and MC type 2 (MC-2) in 217 (75%) patients. Preoperative data for ODI, EQ-5D, VAS-BP, and VAS-LP were comparable for the +MC and -MC groups. Both groups had a statistically significant improvement in PROs from baseline compared with 2-year follow-up (P < 0.001). At 2-year follow-up, both groups had improved with no significant difference between them in regards to ODI (15.5 vs. 17.2, P = 0.208); EQ-5D (0.75 vs. 0.72, P = 0.167); VAS-BP (27.1 vs. 28.3, P = 0.617); VAS-LP (26.8 vs. 25.0, P = 0.446); and patient satisfaction (74% vs. 76%, P = 0.878).

CONCLUSION

MCs were not found to be associated with health-related quality of life, disability, back- or leg pain, or patient satisfaction 2 years after discectomy.

LEVEL OF EVIDENCE

2.

Comparison of dynamic response of three TLIF techniques on the fused and adjacent segments under vibration

To explore which TLIF techniques are advantageous in reducing the risk of complications and conducive to bone fusion under the vibration. The L1-L5 finite element lumbar model was modified to simulate three different TLIF techniques (a unilateral standard cage, a crescent-shaped cage, and bilateral standard cages). The results showed that the crescent-shaped cage may reduce the risk of subsidence and provide a more stable and suitable environment for vertebral cell growth under the vibration compared to the other TLIF techniques. Unilateral cage may increase the risk of adjacent segment disease and cage failure including fatigue failure under vibration.

Association between types of Modic changes in the lumbar region and low back pain in a large cohort: the Wakayama spine study

PURPOSE

The clinical significance of Modic changes in low back pain (LBP) is yet to be clarified. Thus, this study aimed to examine the association between Modic changes and LBP after adjustment for confounding factors.

METHODS

We evaluated participants in the second Wakayama Spine Study. The degree of endplate changes as measured using magnetic resonance imaging was classified based on the Modic classification system. The prevalence of the types of Modic change in the lumbar region and at each level was assessed. Multivariate logistic regression analysis was conducted to determine the association between the types of Modic changes and LBP with adjustment for age, sex, body mass index, disc degeneration score, and disc displacement score. The LBP intensity was also compared according to the Visual Analogue Scale (VAS) score among the three types of Modic change.

RESULTS

Overall, 814 subjects were evaluated. Type II Modic changes were the most prevalent (41.9%). Only type I Modic changes were significantly associated with LBP (odds ratio): 1.84, 95% confidence interval [CI]: 1.1-2.9). The LBP VAS score was significantly higher in subjects with type I Modic change than that in those with no Modic change (23.9 ± 26.3 vs. 9.9 ± 19.4, p < 0.05).

CONCLUSION

Type I Modic changes in the lumbar region are significantly associated with LBP. Profiling Modic changes may be helpful to improve targeted treatment of LBP.

Quantifying the effect of posterior spinal instrumentation on the MRI signal of adjacent intervertebral discs

STUDY DESIGN

Ex vivo porcine imaging study.

OBJECTIVES

Quantitatively evaluate change in MRI signal at the discs caudal to spinal fusion instrumentation. Individuals who receive posterior spinal instrumentation are at risk of developing accelerated disc degeneration at adjacent levels. Degeneration is associated with a loss of biochemical composition and mechanical integrity of the disc, which can be noninvasively assessed through quantitative T2* (qT2*) MRI techniques. However, qT2* is sensitive to magnetic susceptibility introduced by metal.

METHODS

Nine ex vivo porcine lumbar specimens were imaged with 3 T MRI. Fast spin-echo T2-weighted (T2w) images and gradient-echo qT2* maps were acquired, both without and with posterior spinal fusion instrumentation. Average T2* relaxation times of the nuclei pulposi (NP) were measured at the adjacent and sub-adjacent discs and measurements were compared using t tests before and after instrumentation. The size of the signal void and metal artifact were determined (modified ASTM F2119-07) within the vertebral body and spinal cord for both MRI sequences. The relationship between T2* signal loss and distance from the instrumentation was evaluated using Pearson's correlation.

RESULTS

There was no significant difference between adjacent and sub-adjacent NP T2* relaxation time prior to instrumentation (p = 0.86). Following instrumentation, there was a significant decrease in the T2* relaxation time at the adjacent NP (average = 20%, p = 0.02), and no significant difference at the sub-adjacent NP (average = - 3%, p = 0.30). Furthermore, there was a significant negative correlation between signal loss and distance to disc (r = - 0.61, p < 0.01).

CONCLUSIONS

Spinal fusion instrumentation interferes with T2* relaxation time measurements at the adjacent disc but not at the sub-adjacent discs. However, there is sufficient signal at the adjacent disc to quantify changes in the T2* relaxation time following spinal fusion. Hence, baseline MRI scan following spinal fusion surgery are required to interpret and track changes in disc health at the caudal discs.

LEVEL OF EVIDENCE

N/A.

Adjacent-segment disease after L3-4 posterior lumbar interbody fusion: does L3-4 fusion have cranial adjacent-segment degeneration similar to that after L4-5 fusion?

OBJECTIVE

Posterior lumbar interbody fusion (PLIF) is a widely accepted procedure for degenerative lumbar diseases, and there have been many reports concerning adjacent-segment disease (ASD) after PLIF. In the reports of ASD in which the fusion level was limited to 1 segment, all reports describe ASD of the L3-4 segment after L4-5 PLIF. On the basis of these reports, it is thought that ASD mainly occurs at the cranial segment. However, no report has covered ASD after L3-4 PLIF. Therefore, the authors investigated ASD after L3-4 PLIF.

METHODS

In conducting a retrospective case series analysis, the authors reviewed a surgical database providing details of all spine operations performed between 2006 and 2017 at a single institution. During that period, PLIF was performed to treat 632 consecutive patients with degenerative lumbar diseases. Of these patients, 71 were treated with L3-4 PLIF alone, and 67 who were monitored for at least 2 years (mean 5.8 years; follow-up rate 94%) after surgery were enrolled in this study. Radiological ASD (R-ASD), symptomatic ASD (S-ASD), and operative ASD (O-ASD) were evaluated. These types of ASD were defined as follows: R-ASD refers to radiological degeneration adjacent to the fusion segment as shown on plain radiographs; S-ASD is a symptomatic condition due to neurological deterioration at the adjacent-segment degeneration; and O-ASD refers to S-ASD requiring revision surgery.

RESULTS

All patients had initial improvement of neurological symptoms after primary PLIF. R-ASD was observed in 32 (48%) of 67 patients. It occurred at the cranial segment in 12 patients and at the caudal segment in 24; R-ASD at both adjacent segments was observed in 4 patients. Thus, the occurrence of R-ASD was more significant in the caudal segment than in the cranial segment. S-ASD was observed in 10 patients (15%), occurring at the cranial segment in 3 patients and at the caudal segment in 7. O-ASD was observed in 6 patients (9%): at the cranial segment in 1 patient and at the caudal segment in 5. Thus, the rate of involvement of the caudal segment was 67% in R-ASD, 70% in S-ASD, and 83% in O-ASD.

CONCLUSIONS

The incidences of R-ASD, S-ASD, and O-ASD were 48%, 15%, and 9%, respectively, after L3-4 PLIF for degenerative lumbar diseases. In contrast to ASD after L4-5 PLIF, ASD after L3-4 PLIF was more frequently observed at the caudal segment than at the cranial segment. In follow-up for patients with L3-4 PLIF, surgeons should pay attention to ASD in the caudal segment.

The Yield of Lumbosacral Spine MRI in Patients with Isolated Chronic Low Back Pain: A Cross-Sectional Study

Background

The role of routine lumbosacral MRI in patients presented with isolated chronic low back pain (CLBP) is still unclear. Most patients with CLBP will show diverting degenerative changes on MRI. As it is uncertain whether surgical treatment of degenerative MRI changes results in alleviation of back pain or not, the necessity of doing a diagnostic lumbosacral MRI remains questionable. This study aimed to evaluate the yield of lumbosacral MRI among Jordanian patients presented with isolated CLBP.

Methods

We reviewed medical records of all patients who presented to neurosurgery outpatient clinic at Jordan University Hospital from December 2016 to December 2019. Only patients with a chief complaint of isolated CLBP were included. We obtained the relevant data from the computerized medical files and detailed radiological findings from their MRI reports.

Results

One hundred and sixty-seven patients (167) matched the inclusion criteria. We reported positive findings in MRI in 112 patients (67%), but 55 patients (32.93%) had normal MRI findings. Dehydration of intervertebral disc was the most common finding. Positive MRI findings were most evident in the middle-age group (41–60 years old). Disc protrusion finding in middle-aged females was significantly less prevalent than males (P = 0.012).

Conclusion

Jordanian patients presented with CLBP have similar worldwide patterns of lumbar degenerative changes. Providing that near one-third of patients with CLBP have normal MRI findings, we suggest following a streamlined protocol for imaging of patients presented with CLBP to reduce healthcare costs.

Simultaneous detection of multiple mRNAs and proteins in bovine IVD cells and tissue with single cell resolution

OBJECTIVES

Interactions of cells with their neighbors and influences by the surrounding extracellular matrix (ECM) is reflected in a cells transcriptome and proteome. In tissues comprised of heterogeneous cell populations or cells depending on ECM signalling cues such as those of the intervertebral disc (IVD), this information is obscured or lost when cells are pooled for the commonly used transcript analysis by quantitative PCR or RNA sequencing. Instead, these cells require means to analyse RNA transcript and protein distribution at a single cell or subcellular level to identify different cell types and functions, without removing them from their surrounding signalling cues.

RESULTS

We developed a simple, sequential protocol combining RNA is situ hybridisation (RISH) and immunohistochemistry (IHC) for the simultaneous analysis of multiple transcripts alongside proteins. This allows one to characterize heterogeneous cell populations at the single cell level in the natural cell environment and signalling context, both in vivo and in vitro. This protocol is demonstrated on cells of the bovine IVD, for transcripts and proteins involved in mechanotransduction, stemness and cell proliferation.

CONCLUSIONS

A simple, sequential protocol combining RISH and IHC is presented that allows for simultaneous information on RNA transcripts and proteins to characterize cells within a heterogeneous cell population and complex signalling environments such as those of the IVD.

Long-term effect of physical inactivity on thoracic and lumbar disc degeneration-an MRI-based analysis of 385 individuals from the general population

BACKGROUND CONTEXT

The correlation between physical inactivity, thoracolumbar disc degeneration, and back pain remains unclear.

PURPOSE

This study investigated the relationship between short- and long-term physical inactivity and degenerative changes of the thoracic and lumbar spine in a southern German cohort from the general population over a time period of 14 years.

STUDY DESIGN/SETTING

This study was designed as a cross-sectional case-control study, nested in a prospective cohort from the "Cooperative Health Research in the Region of Augsburg/Kooperative Gesundheitsforschung in der Region Augsburg" (KORA) study.

PATIENT SAMPLE

All participants in the population-based KORA study were assessed using a physical activity questionnaire to establish a baseline in 1999-2001 (exam 1), within an initial follow up questionnaire in 2006-2008 (exam 2), and a second follow-up questionnaire between 2013 and 2014 (exam 3). A subsample of this group (400 subjects) underwent full body MR scan performed on a 3T magnetic resonance imaging scanner current with exam 3.

OUTCOME MEASURE

Data regarding physical inactivity over a time period of 14 years and back pain, and quantification of thoracic and lumbar disc degeneration on magnetic resonance imaging.

METHODS

Quantification of thoracic and lumbar disc degeneration was performed using the Pfirrmann score. Physical activity was grouped as no physical activity, irregularly for 1 hour, regularly for 1 hour, or regularly for ≥2 hours. This was used to calculate another variable "physical inactivity," with the options of irregular activity ≤1 hour per week or regularly ≥1 hour. Physical labor, walking, and cycling activity were additionally investigated. Correlations between physical inactivity measurements and thoracic and lumbar disc degeneration were analyzed via linear regression models adjusted for age, sex, BMI, hypertension, diabetes, and back pain.

RESULTS

In total, 385 individuals (mean age: 56 years, SD ± 9.19; 58.2% male) were included in this study. Mean summed Pfirrmann score was 2.41 (SD ± 4.19) in the thoracic and 1.78 (SD ± 1.81) in the lumbar spine. The level of current exercise in our cohort varied with 113 (29.4%) subjects exercising regularly ≥2 hours per week, 118 (30.7%) regularly 1 hour per week, 57 (14%) irregularly for about 1 hour per week, and 97 (25.2%) stated not to exercise at exam 3. Disc degeneration was more apparent in those with irregular activity <1 hour compared to those with regular activity of ≥1 hour and more per week (p<.01) and in those with no activity compared to those with regular activity of ≥2 (p<.001) measured using exam 3. Less physical activity over a time period of 14 years correlated with an increase of disc degeneration of the thoracic and lumbar spine after adjustment for age, sex, BMI, hypertension and diabetes mellitus (p<.05). There was no statistically significant association between physical labor, walking activity, or cycling activity with disc degeneration. Additionally, no significant correlations between degree of disc degeneration (p=.990), degree of physical inactivity (p=.158), and back pain were observed.

CONCLUSION

Degree of physical inactivity as measured over a time period of 14 years demonstrated a strong correlation with disc degeneration of the thoracic and lumbar spine.

A comparison of classifiers in biomedical signal processing as a decision support system in disc hernia diagnosis

The aim of this research was to investigate the best methodology for disc hernia diagnosis using foot force measurements from the designed platform. Based on the subjective neurological examination that examines muscle weakness on the nerve endings of the skin area on feet and concludes about origins of nerve roots between spine discs, a platform for objective recordings of the aforementioned muscle weakness has been designed. The dataset included 33 patients with pre-diagnosed L4/L5 and L5/S1 disc hernia on the left or the right side, confirmed with the MRI scanning and neurological exam. We have implemented 5 different classifiers that were found to be the most suitable for smaller dataset and investigated the accuracy of classification depending on the normalization method, linearity/non-linearity of the algorithm, and dataset splitting variation (32-1, 31-2, 30-3, 29-4 patients for training and testing, respectively). The classifier is able to distinguish between four different diagnoses L4/L5 on the left side, L4/L5 on the right side, L5/S1 on the left side and L5/S1 on the right side, as well as to recognize healthy subjects (without disc herniation). The results show that non-linear algorithms achieved better accuracy in comparison to tested linear classifiers, suggesting the expected non-linear connection between the foot force values and the level of disc herniation. Two algorithms with highest accuracy turned out to be Decision Tree and Naïve Bayes, depending on the normalization method. The system is also able to record and recognize improvements in muscle weakness after surgical operation and physical therapy.

The Correlation between Histopathology of Herniated Lumbar Intervertebral Disc and Clinical Findings

Objective

Prolapsed lumbar disc is one of the most frequent diseases, which is usually presented by motor and sensory deficits. Consistency of herniated disc may play a significant role in surgical treatment and postoperative improvement. The objective of this study is to assess whether the histopathological degeneration in the sample of lumbar discs operated on is correlated to clinical variables and surgical outcomes.

Materials and Methods

A randomized double-blind prospective study of lumbar disc prolapse cases over a period of 24 months was done. Forty cases were initially included in the study. All the included cases with a scheduled lumbar discectomy in the Department of Neurosurgery, King Fahd University Hospital, Al-Khobar, Saudi Arabia, during this period were examined histologically.

Results

Finally, 21 patients were only considered in this study due to loss of follow-up of the other 19 patients; of these 21 patients, 18 were male and 3 were female. The youngest patient was 32 years old, and the oldest was 72 years old. There is no significant correlation between the major histopathological changes of the prolapsed discs and the clinical findings of low back pain (correlation coefficient = 0.058, P < 0.8), duration of sciatica (correlation coefficient = -0.337, P < 0.1), paresthesia (correlation coefficient = 0.111, P < 0.6), motor weakness (correlation coefficient = 0.274, P < 0.2), and reflex (correlation coefficient = 0.081, P < 0.7). Meanwhile, the correlation coefficient between numbness and histopathological degeneration score (HPDS) is not defined because all reported cases were presented with numbness.

Conclusions

There is no significant correlation between the histopathological changes of the prolapsed discs and some clinical findings. Moreover, the different types of prolapsed discs' histopathological changes have no impact on the outcome of the surgery. We also concluded that the disc material undergoes certain degenerative processes with age.

Evaluation of disc degeneration adjacent to AOspine A fractures: pre- and post-operative MRI analysis

INTRODUCTION

The management of type A thoracolumbar fractures varies from conservative treatment to multiple level fusion. Indeed, although Magerl defined the type A fracture as a strictly bone injury, several authors suggested associated disc lesions or degeneration after trauma. However, the preservation of mobility of the adjacent discs should be a major issue. This study was conducted to analyze the presence of immediate post-traumatic disc injuries and to know if discs degenerate after receiving treatment.

METHODS

We retrospectively reviewed the files of 27 patients with an AOspine A fracture, corresponding to 34 fractures (64 discs) with pre and post-operative MRI (mean follow-up: 32.4 months). Based on Pfirrmann's and Oner's classifications of disc injuries, two observers analyzed independently the type of lesion in the discs adjacent to the fractured vertebra in immediate post-trauma and at the last follow-up.

RESULTS

The immediate post-traumatic analysis according to Pfirrmann's classification found 97% of the cranial adjacent discs and 100% of the caudal discs classified Pfirrmann 3 or less. The analysis on the secondary MRI revealed that 78% of cranial adjacent discs and 88% of caudal adjacent discs still were classified Pfirrmann 3 or less.

CONCLUSIONS

Since, the great majority of type A fractures does not cause immediate disc injuries, these fractures are, as described by Magerl, strictly bony injuries. The quality of the body reduction seems to prevent secondary degeneration. These results may encourage surgeons not to perform arthrodesis on type A fractures even for A3 and A4.

The effect of non-fusion dynamic stabilization on biomechanical responses of the implanted lumbar spine during whole-body vibration

BACKGROUND AND OBJECTIVE

Non-fusion dynamic stabilization surgery is increasingly popular for treating degenerative lumbar disc disease. However, changes in spine biomechanics after application of posterior dynamic fixation devices during whole-body vibration (WBV) remain unclear. The study aimed to examine the effects of non-fusion dynamic stabilization on biomechanical responses of the implanted lumbar spine to vertical WBV.

METHODS

By modifying L4-L5 segment of the healthy human L1-sacrum finite element model, single-level disc degeneration, dynamic fixation using the BioFlex system and anterior lumbar interbody fusion (ALIF) with rigid fixation were simulated, respectively. Dynamic responses of stress and strain in the spinal levels for the healthy, degenerated, BioFlex and ALIF models under an axial cyclic loading were investigated and compared.

RESULTS

The results showed that endplate stress at implant level was lower in the BioFlex model than in the degenerated and ALIF models, but stress of the connecting rod in the BioFlex system was greater than that in the rigid fixation system used in the ALIF. Compared with the healthy model, stress and strain responses in terms of disc bulge, annulus stress and nucleus pressure at adjacent levels were decreased in the degenerated, BioFlex and ALIF models, but no obvious difference was observed in these responses among the three models.

CONCLUSIONS

This study may be helpful to understand variations in vibration characteristics of the lumbar spine after application of non-fusion dynamic stabilization system.

Injectable Biologics for the Treatment of Degenerative Disc Disease

Purpose of Review

Spinal pain and associated disability is a leading cause of morbidity worldwide that has a strong association with degenerative disc disease (DDD). Biologically based therapies to treat DDD face significant challenges posed by the unique milieu of the environment within the intervertebral disc, and many promising therapies are in the early stages of development. Patient selection, reasonable therapeutic goals, approach, and timing will need to be discerned to successfully translate potential therapeutics. This review provides a brief overview of the status of intradiscal biologic therapies.

Recent Findings

Proposed systemic delivery of therapeutic agents has not progressed very much in large part due to the risk of adverse events in remote tissues plus the very limited vascular supply and therefore questionable delivery to the intervertebral disc nucleus pulposus. Intradiscal delivery of therapeutic proteins shows good potential for clinical trials and translation with encouraging results from large animal pre-clinical studies plus an enhanced understanding of the biology of DDD. There are a few cell-based therapies currently under pre-clinical and clinical trial investigation; however, these attempts continue to be hampered by unknown if any, mechanism of action, no downstream detection of transplanted cells, mixed results concerning efficacy, small sample numbers, and a lack of objective evidence of pain mediation.

Summary

Treatment of DDD using biologically based therapeutics is a widely sought-after goal; however, potential therapies need to address pain and disability in larger, well-controlled studies.

Is the Lipid Content of the Psoas Major Correlated with Chronic Low Back Pain and Spinopelvic Alignment? A Magnetic Resonance Spectroscopic Study

Study Design

Cross-sectional observational study.

Purpose

This study aimed to analyze any potential associations of extramyocellular lipid (EMCL) and intramyocellular lipid (IMCL) contents with (1) the intensity of low back pain (LBP); (2) age, cross-sectional area (CSA), and fatty infiltration (FI) of the psoas major; and (3) spinopelvic parameters.

Overview of Literature

The psoas major has clinically relevant function; however, the association of this muscle with chronic LBP is controversial. Magnetic resonance spectroscopy enables a detailed analysis of the composition of muscular fat tissues such as its EMCL and IMCL contents.

Methods

The study population comprised 40 patients (19 males, 21 females; mean age, 61.7±2.4 years). Possible correlations of LBP Visual Analog Scale (VAS) scores, age, CSA, FI, and spinopelvic parameters with EMCL and IMCL contents of the psoas major were assessed.

Results

No association was identified between the EMCL and IMCL contents and LBP VAS scores (r=0.05, p=0.79 and r=0.06, p=0.75, respectively). The EMCL content correlated with age (r=0.47, p<0.01), body mass index (BMI) (r=0.44, p<0.01), CSA (r=−0.59, p<0.01), and FI (r=0.49, p<0.01). EMCL content showed a significant negative correlation with sacral slope (SS) (r=−0.43, p<0.05) and positive correlation with pelvic tilt (PT) (r=0.56, p<0.01).

Conclusions

EMCL content correlated with age, BMI, CSA, and FI of the psoas major, while IMCL content had no correlation. This study found correlations between SS and PT and EMCL content of the psoas major, but no correlations were found between spinopelvic parameters and IMCL content of the psoas major.

Large Rises in Thoracolumbar Fusions by 2040: A Cause for Concern with an Increasingly Elderly Surgical Population

BACKGROUND

With a growing aging population in the United States, the number of operative lumbar spine pathologies continues to grow. Therefore, our objective was to estimate the future demand for lumbar spine surgery volumes for the United States to the year 2040.

METHODS

The National/Nationwide Inpatient Sample was queried for years 2003-2015 for anterior interbody and posterior lumbar fusions (ALIF, PLF) to create national estimates of procedural volumes for those years. The average age and comorbidity burden was characterized, and Poisson modeling controlling for age and sex allowed for surgical volume prediction to 2040 in 10-year increments. Age was grouped into categories (<25, 25-34, 35-44, 45-54, 55-64, 65-74, 75-84, and >85 years), and estimates of surgical volumes for each age subgroup were created.

RESULTS

ALIF volume is expected to increase from 46,903 to 55,528, and PLF volume is expected to increase from 248,416 to 297,994 from 2020 to 2040. For ALIF, the largest increases are expected in the 45-54 years (10,316 to 12,216) and 75-84 years (2,898 to 5,340) age groups. Similarly the largest increases in PLF will be seen in the 65-74 years (71,087 to 77,786) and 75-84 years (28,253 to 52,062) age groups.

CONCLUSIONS

The large increases in expected volumes of ALIF and PLF could necessitate training of more spinal surgeons and an examination of projected costs. Further analyses are needed to characterize the needs of this increasingly large population of surgical patients.

Intervertebral Disc Disease of the Lumbar Spine in Health Personnel with Occupational Exposure to Patient Handling-A Systematic Literature Review and Meta-Analysis

Lifting or carrying loads or working while the trunk is in a bent position are well established risk factors for the development of disc disease of the lumbar spine (LDD). Patient handling is associated with certain hazardous activities, which can result in exposure to heavy loads and high pressure for the discs of the lumbar spine of the nurses performing these tasks. The purpose of this review was to examine the occurrence of work-related LDD among health personnel (HP) with occupational exposure to patient handling activities in comparison to un-exposed workers. A systematic literature search was conducted using the following databases: PubMed, CINAHL, Scopus, and Web of Science. A meta-analysis of odds ratios (OR) was conducted by stratifying for various factors. Five studies reported a higher prevalence for LDD among nurses and geriatric nurses (11.3-96.3%) compared to all controls (3.78-76.47%). Results of the meta-analysis showed a significantly increased OR for LDD among HP compared to all controls (OR 2.45; 95% confidence interval (CI) 1.41, 4.26). In particular, the results of this review suggest that nurses have a higher probability of developing disc herniation than office workers.

Expression of Glial Cell Line-derived Neurotrophic Factor in the Human Intervertebral Disc

STUDY DESIGN

Biochemical and immunohistochemical analyses by the human intervertebral disc (IVD) cells and tissues.

OBJECTIVE

To examine the expression of glial cell line-derived neurotrophic factor (GDNF) and its receptors, GDNF family receptor (GFR) α1 and rearranged during transfection (RET) in the human IVD cells and the tissues with the early and advanced stages of degeneration.

SUMMARY OF BACKGROUND DATA

The neurotrophin family, including nerve growth factor, has been reported to be expressed in the IVDs and plays a role in hyperalgesia and neuronal sensitization. Despite having properties similar to the nerve growth factor, the expression of GDNF in the IVD remains unknown.

METHODS

Human IVD cells were cultured in monolayer. Immunohistochemical analyses and western blotting were performed to examine the protein levels of GDNF and its receptors. To examine the effect of proinflammatory cytokines, cells were cultured in the presence of interleukin-1β (IL-1β). The immunohistochemical expression of these proteins was also evaluated using human IVD tissues with different stages of degeneration.

RESULTS

Immunofluorescent reactivity against anti-GDNF, GFRα1, and RET antibodies was identified in human IVD cells. In protein extracts from IVD cells, those protein expressions were also identified by Western blot. IL-1β significantly stimulated the mRNA expression of GDNF compared with that of the control group. There was no significant effect of IL-1β on the mRNA expression of GFRα1 and RET. The percentage of GDNF-immunopositive cells in advanced degenerated discs was significantly higher than that in early degenerated discs, whereas those of GFRα1 and RET showed no significant differences.

CONCLUSIONS

GDNF and its receptors were constitutively expressed in the human IVD cells. GDNF expression was significantly enhanced by proinflammatory stimuli, and in the microenvironment with advanced tissue degeneration.

LEVEL OF EVIDENCE

N/A.

Lumbar high-intensity zones on MRI: imaging biomarkers for severe, prolonged low back pain and sciatica in a population-based cohort

BACKGROUND CONTEXT

There is often discrepancy between clinical presentation and lumbar magnetic resonance imaging (MRI) findings.

PURPOSE

The purpose of this study was to assess the relationship of high-intensity zones (HIZs) on MRI with low back pain (LBP), sciatica, and back-related disability.

STUDY DESIGN

Cross-sectional, population-based Southern Chinese cohort study.

PATIENT SAMPLE

Of 1,414 possible participants, data from 1,214 participants (453 males, 761 females; mean age of 48.1±6.3 years) were included.

OUTCOME MEASURES

Presence of single-level, homogeneous multilevel (same type HIZs of morphology and topography) and heterogeneous multilevel (mixed type HIZs of morphology and topography) HIZs and other MRI phenotypes were assessed at each level with T2-weighted 3T sagittal MRI of L1-S1. Associations with LBP, sciatica and Oswestry Disability Index were correlated with HIZ profiles.

RESULTS

In all, 718 individuals had HIZs (59.1%). Disc degeneration/displacement were more prevalent in HIZ individuals (p<.001). HIZ subjects experienced prolonged severe LBP more frequently (39.6% vs. 32.5%; p<.05) and had higher Oswestry Disability Index scores (10.7±13.7 vs. 8.9±11.3; p<.05). Posterior multilevel HIZ were significantly associated with prolonged severe LBP (OR: 2.18; 95% CI:1.42-3.37; p<.05) in comparison to anterior only, anterior/posterior or other patterns of HIZ. Multilevel homogeneous or heterogeneous HIZs were significantly associated with prolonged, severe LBP (OR: 1.53-1.57; p<.05). Individuals with homogeneous HIZs had a higher risk of sciatica (OR: 1.51, 95% CI: 1.01-2.27; p<.05).

CONCLUSIONS

This is the first large-scale study to note that lumbar HIZs, and specific patterns therein, are potentially clinically-relevant imaging biomarkers that are independently and significantly associated with prolonged/severe LBP and sciatica. HIZs, especially homogenous multilevel HIZ, should be noted in the global pain imaging phenotype assessment.

Morphological parameters of fourth lumbar spinous process palpation: a three-dimensional reconstruction of computed tomography

Background

The localization of lumbar fourth spinous process (L4-SP) is an important anatomical landmark, and identifying its accurate position is essential for the diagnosis and treatment of waist diseases.

Methods

Five hundred participants were scanned with positive and lateral computed tomography (CT), which aimed to clarify anatomic characteristics of L4-SP. Anatomical parameters of the surface localization of L4-SP were measured and recorded through a three-dimensional (3D) reconstruction.

Results

Five hundred participants were classified into three types according to the position of BC with the iliac spine. There are just 266 that the line between the highest point of the iliac spine on both sides located on L4-SP (type I, 53.20%), 16 above L4-SP (type II, 3.20%), and 218 below L4-SP (type III, 43.60%). BC in type I (15.92 ± 1.30 mm) is longer than type III (15.56 ± 1.32 mm). While the angle combined with AB and BC is different in the three groups, the angle in type I (173.00 ± 4.83°) is larger than that in type II (164.69 ± 5.50°) and type III (159.45 ± 8.39°). Other measurements were not found any significant differences between above.

Conclusion

The traditional palpation for L4-SP is not absolutely exact. The accuracy rate is only 53.20%, and the errors may cause serious consequences.

Identifying compositional and structural changes in the nucleus pulposus from patients with lumbar disc herniation using Raman spectroscopy

Lower back pain (LBP) is one of the most common musculoskeletal complaints worldwide. Intervertebral disc degeneration (IDD) is considered to be a significant contributor to LBP; however, the mechanisms underlying IDD remain to be fully elucidated. One of the major features of IDD is the decreased content of type II collagen and proteoglycans in the nucleus pulposus (NP). The present study aimed to investigate the biochemical mechanisms of IDD at the microscopic level using Raman spectroscopy. Raman spectroscopy, based on inelastic scattering of light, is an emerging optical technique that may measure the chemical composition of complex biological samples, including biofluids, cells and tissues. In the present study, 30 NP tissue samples from 30 patients who were diagnosed with lumbar disc herniation and received spinal fusion surgery to relieve LBP were obtained and analyzed. Routine pre-operative 3.0T, T2-weighed MRI was used to classify the cases according to Pfirrmann grades and the T2 signal intensity value of the NP was measured. Subsequently, all NP samples were scanned and analyzed using a Laser MicroRaman Spectrometer at room temperature. The Raman spectral results demonstrated that the relative content of proteoglycans, expressed as the relative intensity ratio of two peaks (I₁₀₆₄/I₁₀₀₄), was significantly inversely correlated with the Pfirrmann grade (ρ=-0.6462; P<0.0001), whereas the content of collagen (amide I) was significantly positively correlated with the Pfirrmann grade (ρ=0.5141; P<0.01). In conclusion, the higher relative intensity of the ratio of two peaks (I₁₆₇₀/I₁₆₄₀; Amide I) represented a higher fractional content of disordered collagen, which suggested that the defective collagen structure may lead to NP abnormalities.

Differential proteomic analysis of fetal and geriatric lumbar nucleus pulposus: immunoinflammation and age-related intervertebral disc degeneration

BACKGROUND

Intervertebral disc degeneration (IVDD) is a major cause of low back pain. Although the mechanism of degeneration remains unclear, aging has been recognized as a key risk factor for IVDD. Most studies seeking to identify IVDD-associated molecular alterations in the context of human age-related IVDD have focused only on a limited number of proteins. Differential proteomic analysis is an ideal method for comprehensively screening altered protein profiles and identifying the potential pathways related to pathological processes such as disc degeneration.

METHODS

In this study, tandem mass tag (TMT) labeling was combined with liquid chromatography-tandem mass spectrometry (LC-MS/MS) for differential proteomic analysis of human fetal and geriatric lumbar disc nucleus pulposus (NP) tissue. Parallel reaction monitoring (PRM) and Western blotting (WB) techniques were used to identify target proteins. Bioinformatic analyses, including Gene Ontology (GO) annotation, domain annotation, pathway annotation, subcellular localization and functional enrichment analyses, were used to interpret the potential significance of the protein alterations in the mechanism of IVDD. Student's t-tests and two-tailed Fisher's exact tests were used for statistical analysis.

RESULTS

Six hundred forty five proteins were significantly upregulated and 748 proteins were downregulated in the geriatric group compared with the fetal group. Twelve proteins were verified to have significant differences in abundance between geriatric and fetal NP tissue; most of these have not been previously identified as being associated with human IVDD. The potential significance of the differentially expressed proteins in age-related IVDD was analyzed from multiple perspectives, especially with regard to the association of the immunoinflammatory response with IVDD.

CONCLUSIONS

Differential proteomic analysis was used as a comprehensive strategy for elucidating the protein alterations associated with age-related IVDD. The findings of this study will aid in the screening of new biomarkers and molecular targets for the diagnosis and therapy of IVDD. The results may also significantly enhance our understanding of the pathophysiological process and mechanism of age-related IVDD.

Comparison of effects of four interbody fusion approaches on the fused and adjacent segments under vibration

BACKGROUND

Which lumbar fusion approaches having fewer impacts on the lumbar spine, reducing the risk of complications and the most conducive to bone fusion under whole-body vibration is urgent to know.

OBJECTIVES

This study researched the best approach under vibration by comparing the effects of four different approaches on the spine, especially regarding some significant indexes related to complications and outcomes.

METHODS

The L1-L5 finite element model was modified to simulate anterior, posterior, trans-foraminal and direct lateral lumbar interbody fusion approaches with bilateral pedicle screw fixation at L4-L5 level.

FINDINGS

Anterior lumbar interbody fusion decreased the corresponding vibration amplitude of the dynamic response at adjacent segments compared with the other three approaches. Direct lateral lumbar interbody fusion decreased the maximum stress in the cage, the endplates at the fused level, and the maximum compressive stress at the interface between the cage and endplates. The maximum disc height and segmental lordosis of Direct lateral lumbar interbody fusion model were the highest among these fusion approaches.

INTERPRETATION

Anterior lumbar interbody fusion may provide a more stable environment for the adjacent segments under vibration. Direct lateral lumbar interbody fusion may reduce the risk of subsidence, cage failure, and adjacent segment disease. Direct lateral lumbar interbody fusion may provide a more stable and suitable environment for vertebral cell growth and lead to better fusion outcomes. The findings may help us understand the effect of various fusion approaches on lumbar and provide some references for choosing a fusion approach.

Comparison of inbred mouse strains shows diverse phenotypic outcomes of intervertebral disc aging

Intervertebral disc degeneration presents a wide spectrum of clinically degenerative disc phenotypes; however, the contribution of genetic background to the degenerative outcomes has not been established. We characterized the spinal phenotype of 3 mouse strains with varying cartilage-regenerative potential at 6 and 23 months: C57BL/6, LG/J and SM/J. All strains showed different aging phenotypes. Importantly, LG/J mice showed an increased prevalence of dystrophic disc calcification in caudal discs with aging. Quantitative-histological analyses of LG/J and SM/J caudal discs evidenced accelerated degeneration compared to BL6, with cellular disorganization and cell loss together with fibrosis of the NP, respectively. Along with the higher grades of disc degeneration, SM/J, at 6M, also differed the most in terms of NP gene expression compared to other strains. Moreover, although we found common DEGs between BL6 and LG/J aging, most of them were divergent between the strains. Noteworthy, the common DEGs altered in both LG/J and BL6 aging were associated with inflammatory processes, response to stress, cell differentiation, cell metabolism and cell division. Results suggested that disc calcification in LG/J resulted from a dystrophic calcification process likely aggravated by cell death, matrix remodelling, changes in calcium/phosphate homeostasis and cell transformation. Lastly, we report 7 distinct phenotypes of human disc degeneration based on transcriptomic profiles, that presented similar pathways and DEGs found in aging mouse strains. Together, our results suggest that disc aging and degeneration depends on the genetic background and involves changes in various molecular pathways, which might help to explain the diverse phenotypes seen during disc disease.

Impact of knee osteoarthritis on surgical outcomes of lumbar spinal canal stenosis

OBJECTIVE

Lumbar spinal canal stenosis (LSS) and knee osteoarthritis (KOA), both of which are age-related degenerative diseases, are independently correlated with increased pain and dysfunction of the lower extremities. However, there have been few studies that investigated whether LSS patients with KOA exhibit poor clinical recovery following lumbar spinal surgery. The aim of this study was to elucidate the surgical outcomes of lumbar spinal surgery for LSS patients with KOA using multiple health-related quality of life (HRQOL) parameters.

METHODS

A total of 865 consecutive patients who underwent posterior lumbar spinal surgery for LSS were retrospectively reviewed. Baseline characteristics, radiographic parameters, perioperative factors, and multiple HRQOL parameters were analyzed preoperatively and at 1-year follow-up. HRQOL items included the Zurich Claudication Questionnaire, Oswestry Disability Index, Medical Outcomes Study 36-Item Short-Form Health Survey (SF-36), and Japanese Orthopaedic Association Back Pain Evaluation Questionnaire (JOABPEQ). The effectiveness of surgical treatment was assessed using the JOABPEQ. The treatment was regarded as effective when it resulted in an increase in postoperative JOABPEQ score by ≥ 20 points compared with preoperative score or achievement of a postoperative score of ≥ 90 points in those with a preoperative score of < 90 points.

RESULTS

A total of 32 LSS patients with KOA were identified, and 128 age- and sex-matched LSS patients without KOA were selected as controls. In both groups, all HRQOL parameters markedly improved at the 1-year follow-up. On the SF-36, the postoperative mean score for the role physical domain was significantly lower in the KOA group than in the control group (p = 0.034). The treatment was significantly less "effective" in the social life domain of JOABPEQ in the KOA group than in the control group (p < 0.001).

CONCLUSIONS

The surgical outcomes of LSS patients with KOA are favorable, although poorer than those of LSS patients without KOA, particularly in terms of social life and activities. These results indicate that LSS patients with KOA experience difficulty in routine work or ordinary activities due to knee pain or restricted knee ROM even after lumbar spinal surgery. Hence, preoperative KOA status warrants consideration when planning lumbar spinal surgery and estimating surgical outcomes of LSS.

Alterations in ECM signature underscore multiple sub-phenotypes of intervertebral disc degeneration

The intervertebral disc is a specialized connective tissue critical for absorption of mechanical loads and providing flexibility to the spinal column. The disc ECM is complex and plays a vital role in imparting tissue its biomechanical function. The central NP is primarily composed of large aggregating proteoglycans (PGs) while surrounding AF is composed of fibrillar collagens, I and II. Aggrecan and versican in particular, due to their high concentration of sulfated GAG chains form large aggregates with hyaluronic acid (HA) and provide water binding capacity to the disc. Degradation of aggrecan core protein due to aggrecanase and MMP activity, SNPs that affect number of chondroitin sulfate (CS) substitutions and alteration in enzymes critical in synthesis of CS chains can impair the aggrecan functionality. Similarly, levels of many matrix and matrix-related molecules e.g. Col2, Col9, HAS2, ccn2 are dysregulated during disc degeneration and genetic animal models have helped establish causative link between their expression and disc health. In the degenerating and herniated discs, increased levels of inflammatory cytokines such as TNF-α, IL-1β and IL-6 are shown to promote matrix degradation through regulating expression and activity of critical proteases and stimulate immune cell activation. Recent studies of different mouse strains have better elucidated the broader impact of spontaneous degeneration on disc matrix homeostasis. SM/J mice showed an increased cell apoptosis, loss of cell phenotype, and cleavage of aggrecan during early stages followed by tissue fibrosis evident by enrichment of several collagens, SLRPs and fibronectin. In summary, while disc degeneration encompasses wide spectrum of degenerative phenotypes extensive matrix degradation and remodeling underscores all of them.

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The intervertebral disc absorbs loads and provides flexibility to the spine.

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The ECM is complex and vital for imparting tissue its biomechanical function.

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Numerous types of proteoglycans and collagens designate the quality of the disc.

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Many matrix and matrix-related molecules are dysregulated during disc degeneration.

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Matrix degradation and remodeling underscores wide spectrum of phenotype.

An exploratory study of different definitions and thresholds for lumbar disc degeneration assessed by MRI and their associations with low back pain using data from a cohort study of a general population

BACKGROUND

Lumbar disc degeneration seen on magnetic resonance imaging (MRI) is defined as loss of signal intensity and/or disc height, alone or in combination with other MRI findings. The MRI findings and thresholds used to define disc degeneration vary in the literature, and their associations with low back pain (LBP) remain uncertain.

OBJECTIVE

To explore how various thresholds of lumbar disc degeneration alter the association between disc degeneration and self-reported LBP.

METHODS

An exploratory, cross-sectional cohort study of a general population. Participants in the cohort 'Backs-on-Funen' had MRI scans and completed questionnaires about LBP at ages 41, 45 and 49 years. The MRI variables, signal intensity (Grades 0-3) and disc height (Grades 0-3), were dichotomised at different thresholds. Logistic regression analyses were used to determine associations. Arbitrarily, a difference in odds ratio (OR) of > 0.5 between thresholds was considered clinically relevant. Receiver Operating Characteristic curves were used to investigate differences between diagnostic values at each threshold.

RESULTS

At age 41, the difference in ORs between signal loss and LBP exceeded 0.5 between the thresholds of ≥2 (OR = 2.02) and = 3 (OR = 2.57). Difference in area under the curves (AUC) was statistically significant (p = 0.02). At ages 45 and 49, the difference in ORs exceeded 0.5 between the thresholds of ≥2 and = 3, but the differences between AUC were not statistically significant. At age 41, the difference in ORs between disc height loss and LBP at the thresholds of ≥1 (OR = 1.44) and ≥ 2 (OR = 2.53) exceeded 0.5. Differences in AUC were statistically significant (p = 0.004). At age 49, differences in ORs exceeded 0.5 (OR = 2.49 at the ≥1 threshold, 1.84 at ≥2 and 0.89 at =3). Differences between AUC were not statistically significant.

CONCLUSION

The results suggest that the thresholds used to define the presence of lumbar disc degeneration influence how strongly it is associated with LBP. Thresholds at more severe grades of disc signal and disc height loss were more strongly associated with LBP at age 41, but thresholds at moderate grades of disc degeneration were most strongly associated with LBP at ages 45 and 49.