Degeneration of the cervical disc: histology compared with radiography and magnetic resonance imaging

Cervical Spondylosis Diagnosis Based on Convolutional Neural Network with X-ray Images

The increase in Cervical Spondylosis cases and the expansion of the affected demographic to younger patients have escalated the demand for X-ray screening. Challenges include variability in imaging technology, differences in equipment specifications, and the diverse experience levels of clinicians, which collectively hinder diagnostic accuracy. In response, a deep learning approach utilizing a ResNet-34 convolutional neural network has been developed. This model, trained on a comprehensive dataset of 1235 cervical spine X-ray images representing a wide range of projection angles, aims to mitigate these issues by providing a robust tool for diagnosis. Validation of the model was performed on an independent set of 136 X-ray images, also varied in projection angles, to ensure its efficacy across diverse clinical scenarios. The model achieved a classification accuracy of 89.7%, significantly outperforming the traditional manual diagnostic approach, which has an accuracy of 68.3%. This advancement demonstrates the viability of deep learning models to not only complement but enhance the diagnostic capabilities of clinicians in identifying Cervical Spondylosis, offering a promising avenue for improving diagnostic accuracy and efficiency in clinical settings.

Nucleus high intensity in the T2-weighted MRI is a potential predictor of annulus tear in cervical injured patients: a case comparative study

BACKGROUND

Segmental fusion operations assume paramount significance for individuals afflicted by full layers of annulus tears as they avert the perils of rapid disc degeneration and segmental instability. Structures with high signal intensity in the T2-weighted MRI can predict potential damage to the injured segment. Since local structures are shortly related biomechanically, this may be an effective predictor for annulus tears.

METHODS

A retrospective analysis of the clinical data of 57 patients afflicted by cervical injuries and subjected to single-segment ACDF has been performed in this study. The surgeon performed intraoperative exploration to assess the integration status of the annulus. The signal intensity of the prevertebral space, nucleus, and injured vertebral bodies were judged in the T2-weighted imaging data. Regression analyses identified independent predictors for annulus tears, and the area under the receiver operating characteristic curve (AUC) was computed to evaluate the predictive performance of potential independent predictors.

RESULTS

The occurrence of nucleus high intensity was significantly higher among individuals with annulus tears, and the nucleus high intensity was deemed an independent predictor for determining the presence of intraoperative visible annulus tears in patients with cervical injuries. AUC for nucleus high intensity was calculated as 0.717, with a corresponding p-value less than 0.05.

CONCLUSIONS

In the realm of diagnosing annulus tears in injured cervical patients, nucleus high intensity in the T2-weighted MRI emerges as a promising predictive factor. Notably, this applies specifically to patients devoid of fracture and visible annulus tears in their MRI scans. Such positive outcomes should be regarded as prospective indications for ACDF.

Biomechanical effect of C5-C6 intervertebral disc degeneration on the human lower cervical spine (C3-C7): a finite element study

The biomechanical effects of intervertebral discs and facet joints degeneration on the cervical spine are essential to understanding the mechanisms of spinal disorders to improve pathological and clinical treatment. In this study, the biomechanical effects of a progressively degenerated C5-C6 segment on the human lower cervical spine are determined by a detailed simulation of intervertebral disc degeneration. A detailed asymmetric three-dimension intact finite element model was developed using computed tomography scan data of the human lower cervical spine (C3-C7). The intact finite element model was then modified at the C5-C6 segment to build three degenerated models, such as mild, moderate, and severe degeneration. The physiological compressive load 73.6 N, and moment 1 Nm were applied at the superior endplate of the vertebra C3, and the inferior endplate of the C7 vertebra was a constraint for all degrees of freedom. Range of motion, maximum von Mises stress in the annulus, intradiscal pressure, and facet joint force of the degenerated models were computed. With progressive degeneration in the C5-C6 segment, the range of motion of degenerated and normal segments decreases in all postures. Intradiscal pressure of the degenerated segment decreases but increases in normal segments of degenerated segment C5-C6, and facet joint forces increase at both degenerated and normal segments. This study emphasizes that the degenerated disc alters the degenerated and normal segments' motion and loading patterns. The abnormal increase in facet joint force in the degenerated models threatened to accelerate the degeneration in the normal segments.

Application study of 3D LAVA-Flex on lumbar intervertebral disc degeneration

Background

Degeneration of the intervertebral discs are very common diseases, indicating the specific or malignant changes in intervertebral disc component, structure and function. Imaging examination is currently used to evaluate the severity of lumbar intervertebral disc degeneration. This study was designed to investigate the diagnostic value of 3D LAVA-Flex in lumbar intervertebral disc degeneration.

Material and methods

Sagittal 3D LAVA-Flex and T2WI scans were performed in 45 patients with lumbar intervertebral disc degeneration. On T2WI, the degenerated intervertebral disc in every patient was evaluated using Pfirrmann grade. Then, the patients were re-evaluated using 3D LAVA-Flex with considerations of the distinction of nucleus pulposus and annulus fibrosus, hypointense signal of intervertebral disc and height of intervertebral disc. The evaluation results were compared between 3D LAVA-Flex and T2WI. Virtual endoscopy was also performed to evaluate the degenerated intervertebral disc.

Results

The intermediate–intense signal of nucleus pulposus and complete ring-shaped hyperintense signal of annulus fibrosus were found and the distinction of nucleus pulposus and annulus fibrosus was clear in the normal intervertebral disc on 3D LAVA-Flex. The incidence of linear hypointensity of narrowed intervertebral space (65/91) was higher than that of normal intervertebral space (4/134) (P = 0.000). A good consistency was shown between the LAVA-Flex grade and T2WI-based Pfirrmann grade. Virtual endoscopy based on 3D LAVA-Flex could help clearly show the anatomic relationship between the degenerated disc and intervertebral foramen.

Conclusions

3D LAVA-Flex and T2WI show similar efficacy in evaluating lumbar intervertebral disc degeneration. 3D LAVA-Flex-based virtual endoscopy possesses great potential in the study of intervertebral disc abnormalities.

Association between Modic changes, disc degeneration, and neck pain in the cervical spine: a systematic review of literature

BACKGROUND

The contribution of Modic changes (MCs) in relation to spinal pain and degenerative changes has been evaluated frequently. However, most studies focus on lumbar spine. The association between MCs, neck pain, and cervical disc degeneration is not clear.

PURPOSE

The objective of this study was to review current literature on the association between MCs, cervical disc degeneration, and neck pain.

STUDY DESIGN

A systematic review METHODS: A literature search was performed in PubMed, Embase, and Web of Science using a sensitive search string combination. Studies were selected by predefined selection criteria and risk of bias was assessed using a validated Cochrane Checklist adjusted for this purpose.

RESULTS

Fourteen articles that associated MCs with neck pain and/or cervical disc degeneration were included in the present study. Ten articles showed low risk of bias and four showed intermediate risk of bias. The prevalence of MCs in cervical spine varied from 5% to 40% and type II was predominant. Patients with MCs were reported to experience more neck pain and disability. Cervical disc degeneration was detected more frequently in patients with MCs.

CONCLUSIONS

Modic changes were found to be associated with neck pain and with disc degeneration. Therefore, the large variation in prevalence that is reported is highly dependent on the nature of the studied population.

Immuohistochemical score of matrix metalloproteinase-1 may indicate the severity of symptomatic cervical and lumbar disc degeneration

BACKGROUND CONTEXT

Intervertebral disc (IVD) degeneration is related to numerous risk factors, including obesity. Leptin, one of the commonly measured adipokines, is proven to play an important role in the pathogenesis of IVD degeneration. In the context of IVD degeneration, matrix metalloproteinase-1 (MMP-1), which is upregulated and activated by leptin, is the most abundant catabolic enzyme. It remains unclear which of the factors mentioned above is most strongly associated with IVD degeneration.

PURPOSE

To investigate the influence of MMP-1 in IVD degeneration, we determined the strength of different predictors, including age, sex, magnetic resonance imaging (MRI), Modic changes (MCs), body mass index (BMI), leptin, and MMP-1. This was achieved by assessing the correlation among these factors and histologic degeneration score (HDS).

STUDY DESIGN

This study included 89 patients undergoing cervical discectomy for disc herniation, 93 who underwent lumbar discectomy, and 90 control subjects. Herniated disc tissue and plasma were used after the study was approved by the Human Ethics Review Committee at the authors' institution.

METHODS

Hematoxylin and eosin (H&E), Alcian blue-PAS and immunohistochemical (IHC) staining were performed to measure the expression levels of leptin and MMP-1. Circulating plasma levels of leptin and MMP-1 were measured using an enzyme-linked immunosorbent assay. To assess the correlation with HDS, measurements of age, sex, BMI, MRI scale, MCs scale, leptin/MMP-1 plasma concentration, and leptin/MMP-1 IHC expression were analyzed.

RESULTS

Patients with cervical or lumbar discectomy had significantly higher BMI than controls. Significantly more men than women were involved in the lumbar patients as compared with the cervical patients and the control subjects. After adjustment for age and sex, plasma leptin and leptin IHC score correlated significantly with BMI in patients with cervical or lumbar discectomy. Age, sex, MRI scale, MCs scale, and leptin/MMP-1 plasma concentration were not positively correlated with HDS. HDS was significantly associated with BMI, leptin IHC score, and MMP-1 IHC score. After a stepwise-multiple linear regression analysis to evaluate the strength of the correlations between HDS and various factors, only the MMP-1 IHC score demonstrated an independent association with HDS in patients with degeneration of the cervical or lumbar disc.

CONCLUSIONS

MMP-1 IHC score is an independent predictor of the severity of cervical or lumbar IVD degeneration.

CLINICAL SIGNIFICANCE

MMP-1 IHC score may be used as an indicator of IVD degeneration.

Patterns of Cervical Disc Degeneration: Analysis of Magnetic Resonance Imaging of Over 1000 Symptomatic Subjects

STUDY DESIGN

Cross-sectional study.

OBJECTIVES

The aim of this study was to evaluate cervical disc degeneration on magnetic resonance imaging (MRI) in a large population of symptomatic patients and to provide baseline data on the pattern of degeneration in order to understand how the cervical spine ages.

METHODS

We performed a cross-sectional study of 1059 patients who underwent upright cervical MRI for neck pain with and without neurological symptoms. A total of 6354 cervical discs from C2/3 to C7/T1 were evaluated. Cervical disc degeneration was evaluated on T2-weighted MRI and graded into 4 categories (Grades 0-III). Positive degeneration was defined as greater than Grade II. The correlation between age and total grade of degeneration of each patient was evaluated, as well as the prevalence and pattern of degeneration.

RESULTS

The average number of degenerated disc levels and the total grade of cervical disc degeneration significantly increase with age. In the patient group with 1-level degeneration, C5/6 was the most common degenerated level followed by C4/5 and C6/7. In the group with 2-level degeneration, C5/6 & C6/7 was most common followed by C4/5 & C5/6 and C3/4 & C4/5. Skip level degeneration was significantly rarer than contiguous level degeneration, and C7/T1 and C2/3 were the most unlikely to degenerate in multilevel degeneration.

CONCLUSION

Disc degeneration is most common in the middle cervical spine (C5/6) and progresses to contiguous levels, except for C7/T1 and C2/3. This pattern may play a role in adjacent-level disc degeneration associated with spinal fusion.

Magnetic Resonance Classification System of Cervical Intervertebral Disk Degeneration: Its Validity and Meaning

STUDY DESIGN

Retrospective analysis of kinetic magnetic resonance images (kMRIs).

OBJECTIVE

(1) To analyze the changes seen on MRI related to disk degeneration and to develop a new grading system for cervical disk degeneration. (2) To evaluate the reliability and validity of the grading system.

SUMMARY OF BACKGROUND DATA

Few have studied the relationship between changes seen on MRI with cervical disk degeneration and the chronological order of disk degeneration. A few grading systems for cervical disk degeneration have been reported; however, there have been problems related to subjectivity and lack of a clear, reliable algorithm.

METHODS

A total of 300 cervical intervertebral disks were graded for nucleus color, structure, disk bulge, and disk height. On the basis of the analysis, a new grading system consisting of 4 grades (grade 0-III) and algorithm were developed. Intraobserver and interobserver reliabilities were assessed. A total of 2802 intervertebral disks were then evaluated using the grading system to correlate disk degeneration grades with patient age and function and to evaluate the validity of the new system.

RESULTS

On the basis of cross-table analysis, disk degeneration presents in the following order: (1) decrease and/or change of nucleus intensity; (2) loss of distinction between nucleus and annulus; (3) positive disk bulge; and (4) disk height decrease. The κ-coefficients for intraobserver and interobserver agreements were 0.96 and 0.90, respectively. Severe disk degeneration is most common at C5/C6 followed by C6/C7 and C4/C5, and total disk degeneration grade is correlated with age (R=0.467). There was a decrease of angular motion in grades I-III and an increase in translational motion and decrease of space available for the cord in grades II-III.

CONCLUSIONS

We developed a new classification system of cervical disk degeneration based on analysis of the changes seen on MRI. Reliability tests indicated high reproducibility of this system, and further analysis confirmed its validity and clinical significance.

Radiological Parameters of Undegenerated Cervical Vertebral Segments in a Korean Population

BACKGROUND

Several scoring systems for cervical disc and facet joint degeneration, using radiography or computed tomography, have been developed and tested for reliability. However, definitions of disc height and facet joint space narrowing vary. To our knowledge, no study has reported quantitative data for normal radiologic values of the cervical spine in the Korean population. The purpose of this study is to determine normal cervical disc height, disc height ratio, and facet joint space values, and investigate the correlation between demographic data and these values.

METHODS

We performed a retrospective study of patients who underwent artificial disc replacement of the cervical spine. Disc heights and facet joint spaces were measured using cervical neutral lateral radiographs and computed tomography. The means, standard deviations, and 95% confidence intervals of the values were determined.

RESULTS

We measured 148 intervertebral discs and 352 posterior facet joints. The mean disc height measured by plain radiography and computed tomography was 5.57 ± 0.81 mm and 4.94 ± 0.94 mm, respectively. The mean facet joint space values measured by plain radiography and computed tomography were 1.94 ± 0.45 mm and 1.43 ± 0.39 mm, respectively. The disc heights and facet joint space values measured by plain radiography were greater than those measured by computed tomography. The lower limit of the 95% confidence interval of the disc height ratio calculated by plain radiography and computed tomography was greater than 0.94 at all levels except for C5-6. Patient height and disc height showed a tendency of positive correlation.

CONCLUSIONS

In a Korean population, the normal cervical disc height was about 5.0 mm and the normal facet joint space was 1.4 mm. Disc height ratio can reliably identify normal cervical disc height in patients with mild degeneration. Patient height was positively correlated with disc height and facet joint space. Thus, when selecting a cervical implant, surgeons should consider patient height as well as estimated normal disc height.

Novel Hemi-Staple for the Fusionless Correction of Pediatric Scoliosis: Influence on Intervertebral Disks and Growth Plates in a Porcine Model

STUDY DESIGN

In vivo porcine model utilized to evaluate the influence of an intravertebral fusionless growth modulating device (hemi-staple) on intervertebral disks and growth plates.

OBJECTIVE

To evaluate the radiographic and histologic changes in disks and growth plates with the purpose of measuring influence of the explored hemi-staple.

SUMMARY OF BACKGROUND DATA

Fusionless growth modulation for the early treatment of scoliosis should insure the long-term viability of the intervertebral disk and successfully reduce or arrest local growth. A novel hemi-staple that proved effective in the control of coronal spinal alignment warranted further analyses of its influence on the disk health and growth-plate morphology.

METHODS

A hemi-staple that inhibited local vertebral growth exclusive of the disk was introduced over T5-T8 in 4 immature pigs (16 vertebrae; experimental), whereas 3 underwent surgery without instrumentation (sham) and 2 had no intervention (control). Three-month follow-up before animal euthanasia provided radiographic (disk height and health) and histologic (growth plate morphology, disk health, and type X collagen distribution) analyses.

RESULTS

No postoperative complications were experienced. Radiographic data returned inverse disk wedging (greater disk height adjacent to device, 2.6±0.7 mm compared with the noninstrumented side, 1.8±0.5 mm) in experimental segments and suggested disk viability. Histologic data confirmed device growth modulation through significant local reduction of growth plate hypertrophic zone (125.64±16.61 μm and 61.16±8.25 μm in noninstrumented and instrumented sections, respectively) and cell height (16.14±1.87 μm and 9.22±1.57 μm in noninstrumented and instrumented sections, respectively). A variability of disk health, dependant of device insertion location, was observed. Type X collagen was consistently identified in experimental growth plates and absent from intervertebral disks.

CONCLUSIONS

Hemi-staples decreased growth plate hypertrophic zone and cell height, and, depending on device insertion site, showed positive signs of disk health sustainability. Spinal growth modulation achieved exclusive of disk compression, as practiced by this method, offers unique advantages over other fusionless techniques. This technique may provide a suitable and attractive alternative for the early treatment of idiopathic scoliosis.

Qualitative grading of disc degeneration by magnetic resonance in the lumbar and cervical spine: lack of correlation with histology in surgical cases

BACKGROUND

Clinically, magnetic resonance (MR) imaging is the most effective non-invasive tool for assessing IVD degeneration. Histological examination of the IVD provides a more detailed assessment of the pathological changes at a tissue level. However, very few reports have studied the relationship between these techniques. Identifying a relationship may allow more detailed staging of IVD degeneration, of importance in targeting future regenerative therapies.

OBJECTIVES

To investigate the relationship between MR and histological grading of IVD degeneration in the cervical and lumbar spine in patients undergoing discectomy.

METHODS

Lumbar (N = 99) and cervical (N = 106) IVD samples were obtained from adult patients undergoing discectomy surgery for symptomatic IVD herniation and graded to ascertain a histological grade of degeneration. The pre-operative MR images from these patients were graded for the degree of IVD (MR grade) and vertebral end-plate degeneration (Modic Changes, MC). The relationship between histological and MR grades of degeneration were studied.

RESULTS

In lumbar and cervical IVD the majority of samples (93%) exhibited moderate levels of degeneration (ie MR grades 3-4) on pre-operative MR scans. Histologically, most specimens displayed moderate to severe grades of degeneration in lumbar (99%) and cervical spine (93%). MR grade was weakly correlated with patient age in lumbar and cervical study groups. MR and histological grades of IVD degeneration did not correlate in lumbar or cervical study groups. MC were more common in the lumbar than cervical spine (e.g. 39 versus 20% grade 2 changes; p < 0.05), but failed to correlate with MR or histological grades for degeneration.

CONCLUSIONS

In this surgical series, the resected IVD tissue displayed moderate to severe degeneration, but there is no correlation between MR and histological grades using a qualitative classification system. There remains a need for a quantitative, non-invasive, pre-clinical measure of IVD degeneration that correlates with histological changes seen in the IVD.

Reliable Magnetic Resonance Imaging Based Grading System for Cervical Intervertebral Disc Degeneration

STUDY DESIGN

Observational.

PURPOSE

To develop a simple and comprehensive grading system for cervical discs that precisely, consistently and meaningfully presents radiologic and morphologic data.

OVERVIEW OF LITERATURE

The Thompson grading system is commonly used to classify the severity of degenerative lumbar discs on magnetic resonance imaging (MRI). Inherent differences in the morphological and physiological characteristics of cervical discs have hindered development of precise classification systems. Other grading systems have been developed for degenerating cervical discs, but their versatility and feasibility in the clinical setting is suboptimal.

METHODS

MRIs of 46 human cervical discs were de-identified and displayed in PowerPoint format. Each slide depicted a single disc with a normal (grade 0) disc displayed in the top right corner for reference. The presentation was given to 25 physicians comprising attending spine surgeons, spine fellows, orthopaedic residents, and two attending musculoskeletal radiologists. The grading system included Grade 0 (normal height compared to C2-3, mid cleft still visible), grade 1 (dark disc, normal height), grade 2 (collapsed disc, few osteophytes), and grade 3 (collapsed disc, many osteophytes). The ease of use of the system was gauged in the participants and the interobserver reliability was calculated.

RESULTS

The intraclass correlation coefficient for interobserver reliability was 0.87, and 0.94 for intraobserver reliability, indicating excellent reliability. Ninety-five percent and 85 percent of the clinicians judged the grading system to be clinically feasible and useful in daily practice, respectively.

CONCLUSIONS

The grading system is easy to use, has excellent reliability, and can be used for precise and consistent clinician communication.

Structural and Ultrastructural Analysis of the Cervical Discs of Young and Elderly Humans

Several studies describing the ultrastructure and extracellular matrix (ECM) of intervertebral discs (IVDs) involve animal models and specimens obtained from symptomatic individuals during surgery for degenerative disease or scoliosis, which may not necessarily correlate to changes secondary to normal aging in humans. These changes may also be segment-specific based on different load patterns throughout life. Our objective was to describe the ECM and collagen profile of cervical IVDs in young (G1 - <35 years) and elderly (G2 - >65 years) presumably-asymptomatic individuals. Thirty cervical discs per group were obtained during autopsies of presumably-asymptomatic individuals. IVDs were analyzed with MRI, a morphological grading scale, light microscopy, scanning electron microscopy (SEM) and immunohistochemistry (IHC) for collagen types I, II, III, IV, V, VI, IX and X. Macroscopic degenerative features such as loss of annulus-nucleus distinction and fissures were found in both groups and significantly more severe in G2 as expected. MRI could not detect all morphological changes when compared even with simple morphological inspection. The loose fibrocartilaginous G1 matrix was replaced by a denser ECM in G2 with predominantly cartilaginous characteristics, chondrocyte clusters and absent elastic fibers. SEM demonstrated persistence of an identifiable nucleus and Sharpey-type insertion of cervical annulus fibers even in highly-degenerated G2 specimens. All collagen types were detected in every disc sector except for collagen X, with the largest area stained by collagens II and IV. Collagen detection was significantly decreased in G2: although significant intradiscal differences were rare, changes may occur faster or earlier in the posterior annulus. These results demonstrate an extensive modification of the ECM with maintenance of basic ultrastructural features despite severe macroscopic degeneration. Collagen analysis supports there is not a "pathologic" collagen type and changes are generally similar throughout the disc. Understanding the collagen and ultrastructural substrate of degenerative changes in the human disc is an essential step in planning restorative therapies.

Sensitivity of magnetic resonance imaging in the diagnosis of mobile and nonmobile L4-L5 degenerative spondylolisthesis

BACKGROUND CONTEXT

Lumbar degenerative spondylolisthesis (LDS) is often diagnosed by conventional supine magnetic resonance imaging (MRI). Numerous studies have shown, however, that the degree of spondylolisthesis can be reduced or disappears when the patient is supine as compared with standing lateral and flexion-extension (SLFE) radiographs.

PURPOSE

To compare the sensitivity of supine MRI with SLFE radiographs in patients with L4-L5 LDS.

STUDY DESIGN

A retrospective imaging study.

PATIENT SAMPLE

Included patients diagnosed with L4-L5 LDS with both SLFE films and supine MRI.

METHODS

Lumbar degenerative spondylolisthesis was defined radiographically as a slip greater than 4.5 mm. Mobile LDS was defined as a difference of greater than 3% in slip percentage between lateral radiographs and sagittal MRIs. Additional measurements included L4-L5 facet effusion diameter on axial MRIs. Measurements were performed by two independent examiners. The kappa coefficient was used to assess the interobserver agreement.

RESULTS

Of 103 patients assessed, 68% were women and the average age was 66 years. Lumbar degenerative spondylolisthesis was seen on 101 (98%) lateral films and 80 (78%) MRIs. Average slip was 10.0 mm for lateral standing radiographs and 6.6 mm on MRI (p<.0001). Fifty (48%) patients were identified with mobile LDS. The positive predictive value of facet joint effusion for mobile LDS increased from 52% for effusions greater than 1 mm to 100% for effusions greater than 3.5 mm.

CONCLUSIONS

This study found that MRI had a sensitivity of 78% for detecting L4-L5 LDS compared with 98% for lateral standing films. We also identified facet effusion size as a marker to predict mobile LDS. These findings suggest that, particularly in the setting of facet effusions, the complete workup of patients in whom LDS is possible should include standing radiographs.

Imbalanced protein expression patterns of anabolic, catabolic, anti-catabolic and inflammatory cytokines in degenerative cervical disc cells: new indications for gene therapeutic treatments of cervical disc diseases

Degenerative disc disease (DDD) of the cervical spine is common after middle age and can cause loss of disc height with painful nerve impingement, bone and joint inflammation. Despite the clinical importance of these problems, in current publications the pathology of cervical disc degeneration has been studied merely from a morphologic view point using magnetic resonance imaging (MRI), without addressing the issue of biological treatment approaches. So far a wide range of endogenously expressed bioactive factors in degenerative cervical disc cells has not yet been investigated, despite its importance for gene therapeutic approaches. Although degenerative lumbar disc cells have been targeted by different biological treatment approaches, the quantities of disc cells and the concentrations of gene therapeutic factors used in animal models differ extremely. These indicate lack of experimentally acquired data regarding disc cell proliferation and levels of target proteins. Therefore, we analysed proliferation and endogenous expression levels of anabolic, catabolic, ant-catabolic, inflammatory cytokines and matrix proteins of degenerative cervical disc cells in three-dimensional cultures. Preoperative MRI grading of cervical discs was used, then grade III and IV nucleus pulposus (NP) tissues were isolated from 15 patients, operated due to cervical disc herniation. NP cells were cultured for four weeks with low-glucose in collagen I scaffold. Their proliferation rates were analysed using 3-(4, 5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide. Their protein expression levels of 28 therapeutic targets were analysed using enzyme-linked immunosorbent assay. During progressive grades of degeneration NP cell proliferation rates were similar. Significantly decreased aggrecan and collagen II expressions (P<0.0001) were accompanied by accumulations of selective catabolic and inflammatory cytokines (disintegrin and metalloproteinase with thrombospondin motifs 4 and 5, matrix metalloproteinase 3, interleukin-1β, interleukin-1 receptor) combined with low expression of anti-catabolic factor (metalloproteinase inhibitor 3) (P<0.0001). This study might contribute to inhibit inflammatory catabolism of cervical discs.

Understanding the native nucleus pulposus cell phenotype has important implications for intervertebral disc regeneration strategies

Low back pain is a leading cause of morbidity in developed societies and is strongly linked to degeneration of the intervertebral disc. The central nucleus pulposus (NP) region is most severely affected during disc degeneration and, consequently, is a focus for novel cell-based regenerative strategies. However, in order to develop such techniques, it is essential to first understand the biology and phenotype of the NP cells intended for repair. Microarray studies have highlighted novel NP markers that will allow a more accurate identification of cells for implantation, and along with other studies, have also revealed the potential importance of a developmental or immature NP cell phenotype in disseminating the optimal cell type for use. Additionally, the degenerative intervertebral disc is a harsh native environment and the effects of this on cells intended for implantation have yet to be fully elucidated; this is crucial for clinical translation of tissue engineered cell-based therapies.

The shear modulus of the nucleus pulposus measured using magnetic resonance elastography: a potential biomarker for intervertebral disc degeneration

PURPOSE

This study aims to: (1) measure the shear modulus of nucleus pulposus (NP) in intact human vertebra-disc-vertebra segments using a magnetic resonance elastography setup for a 7T whole-body scanner, (2) quantify the effect of disc degeneration on the NP shear modulus measured using magnetic resonance elastography, and (3) compare the NP shear modulus to other magnetic resonance-based biomarkers of dis degeneration.

METHODS

Thirty intact human disc segments were classified as normal, mild, or severely degenerated. The NP shear modulus was measured using a custom-made setup that included a novel inverse method less sensitive to noisy displacements. T2 relaxation time was measured at 7T. The accuracy of these parameters to classify different degrees of degeneration was evaluated using receiver operating characteristic curves.

RESULTS

The magnetic resonance elastography measure of shear modulus in the NP was able to differentiate between normal, mild degeneration, and severe degeneration. The T2 relaxation time was able to differentiate between normal and mild degeneration, but it could not distinguish between mild and severe degeneration.

CONCLUSIONS

This study shows that the NP shear modulus measured using magnetic resonance elastography is sensitive to disc degeneration and has the potential of being used as a clinical tool to quantify the mechanical integrity of the intervertebral disc.

Prevalence of disc degeneration in asymptomatic korean subjects. Part 2 : cervical spine

Objective

Similar to back pain, neck pain has recently shown to have increasing prevalence. Magnetic resonance imaging (MRI) is useful in identifying the causes of neck pain. However, MRI shows not only pathological lesions but also physiological changes at the same time, and there are few Korean data. The authors have attempted to analyze the prevalence of disc degeneration in highly selective asymptomatic Korean subjects using MRI.

Methods

We performed 3 T MRI sagittal scans from C2 to T1 on 102 asymptomatic subjects (50 men and 52 women) who visited our hospital between the ages of 14 and 82 years (mean age 46.3 years). All images were read independently by three observers (two neurosurgeons and one neuroradiologist) who were not given any information about the subjects. We classified grading for cervical disc herniation (HN), annular fissure (AF), and nucleus degeneration (ND), using disc degeneration classification.

Results

The prevalence of HN, AF, and ND were 81.0%, 85.9%, and 95.4%, respectively. High prevalence of HN, AF, and ND was shown compared to previous literature.

Conclusion

In asymptomatic Korean subjects, the abnormal findings of 3 T MRI showed a high prevalence in HN, AF, and ND. Several factors might play important roles in these results, such as population-specific characters, MRI field strength, and disc degeneration grading system.

Age-related changes in human cervical, thoracal and lumbar intervertebral disc exhibit a strong intra-individual correlation

INTRODUCTION

Intervertebral disc (IVD) degeneration is characterized as a multifactorial disease, in which the hereditary background is thought to be of high importance. Accordingly, one would expect all spinal levels (lumbar/cervical/thoracal) to be affected by above-average disc degeneration in genetically predisposed individuals. The aim of this study, therefore, was to analyze the amount of degenerative changes in different spine levels in humans from different ages.

MATERIALS AND METHODS

In detail, the presence, localization and abundance of histomorphological changes in the annulus fibrosus (AF) and nucleus pulposus (NP) in the cervical (C5/C6), thoracic (T2/T3) and lumbar (L2/L3) spine were investigated in complete autopsy IVD specimens (47 individuals) covering a complete age range (0-95 years).

RESULTS

Results indicate that the highest degree of histo-degenerative changes were observed in the NP in all spine levels and showed an age-related expression pattern. With regard to the different spine levels, lumbar disc specimen showed significantly more degenerative changes compared to cervical and thoracic discs, whereas no statistical difference was observed between cervical and thoracic discs. In summary, highest grades of degeneration were observed in lumbar discs (especially in the NP). Intra-individual correlations between the degeneration score in the different levels showed a significant individual concordance.

CONCLUSIONS

The intra-individual correlation of degenerative changes in all three examined spine regions further supports the notion that individual, i.e. genetic factors are strong predisposing factor for the development of age-related disc alterations.

Interobserver agreement on MRI evaluation of patients with cervical radiculopathy

AIM

To evaluate the interobserver agreement on magnetic resonance imaging (MRI) evaluation of herniated discs, spondylotic neuroforaminal stenosis, and root compression in patients with recent onset cervical radiculopathy and in addition, to assess the added value of disclosure of clinical information to interobserver agreement.

MATERIALS AND METHODS

The MRI images of 82 patients with less than 1 month of symptoms and signs of cervical radiculopathy were evaluated independently by two neuroradiologists who were unaware of clinical findings. MRI analysis was repeated after disclosure of clinical information. Interobserver agreement was calculated using kappa statistics.

RESULTS

The kappa score for evaluation of herniated discs and of spondylotic foramen stenosis was 0.59 and 0.63, respectively. A kappa score of 0.67 was found for the presence of root compression. After disclosure of clinical information kappa scores increased slightly: from 0.59 to 0.62 for the detection of herniated discs, from 0.63 to 0.66 for spondylotic foramen stenosis, and from 0.67 to 0.76 for root compression.

CONCLUSION

Interobserver reliability of MRI evaluation in patients with cervical radiculopathy was substantial for root compression, with or without clinical information. Agreement on the cause of the compression, i.e., herniated disc or spondylotic foraminal stenosis, was lower.

Qualitative and quantitative assessment of degeneration of cervical intervertebral discs and facet joints

Degeneration of intervertebral discs and facet joints is one of the most frequently encountered spinal disorders. In order to describe and quantify degeneration and evaluate a possible relationship between degeneration and biomechanical parameters, e.g., the intervertebral range of motion and intradiscal pressure, a scoring system for degeneration is mandatory. However, few scoring systems for the assessment of degeneration of the cervical spine exist. Therefore, two separate objective scoring systems to qualitatively and quantitatively assess the degree of cervical intervertebral disc and facet joint degeneration were developed and validated. The scoring system for cervical disc degeneration consists of three variables which are individually scored on neutral lateral radiographs: "height loss" (0-4 points), "anterior osteophytes" (0-3 points) and "endplate sclerosis" (0-2 points). The scoring system for facet joint degeneration consists of four variables which are individually scored on neutral computed tomography scans: "hypertrophy" (0-2 points), "osteophytes" (0-1 point), "irregularity" on the articular surface (0-1 point) and "joint space narrowing" (0-1 point). Each variable contributes with varying importance to the overall degeneration score (max 9 points for the scoring system of cervical disc degeneration and max 5 points for facet joint degeneration). Degeneration of 20 discs and facet joints of 20 patients was blindly assessed by four raters: two neurosurgeons (one senior and one junior) and two radiologists (one senior and one junior), firstly based on first subjective impression and secondly using the scoring systems. Measurement errors and inter- and intra-rater agreement were determined. The measurement error of the scoring system for cervical disc degeneration was 11.1 versus 17.9% of the subjective impression results. This scoring system showed excellent intra-rater agreement (ICC = 0.86, 0.75-0.93) and excellent inter-rater agreement (ICC = 0.78, 0.64-0.88). Surgeons as well as radiologists and seniors as well as juniors obtained excellent inter- and intra-rater agreement. The measurement error of the scoring system for cervical facet joint degeneration was 20.1 versus 24.2% of the subjective impression results. This scoring system showed good intra-rater agreement (ICC = 0.71, 0.42-0.89) and fair inter-rater agreement (ICC = 0.49, 0.26-0.74). Both scoring systems fulfilled the criteria for recommendation proposed by Kettler and Wilke. Our scoring systems can be reliable and objective tools for assessing cervical disc and facet joint degeneration. Moreover, the scoring system of cervical disc degeneration was shown to be experience- and discipline-independent.

Reliability of a magnetic resonance imaging-based grading system for cervical intervertebral disc degeneration

STUDY DESIGN

This was a radiographic reliability study of a novel grading system for cervical intervertebral disc degeneration.

OBJECTIVES

This study aimed to develop and test the reliability of a reproducible grading system for cervical intervertebral disc degeneration on the basis of the routine magnetic resonance imaging (MRI).

SUMMARY OF BACKGROUND DATA

Cervical disc degeneration is common after middle age, and the morphology of cervical disc degenerative disease has often been studied using MRI. There are few specific MRI-based grading systems for cervical intervertebral disc degeneration despite the clinical importance of this problem. This study proposes a novel reproducible grading system for cervical disc degeneration and demonstrates the reliability of this classification scheme.

METHODS

A grading system for cervical intervertebral disc degeneration was developed based on relevant previous literature. MRI grading of 300 cervical intervertebral discs using T2-weighted sagittal images was performed by 4 spinal surgeons (observers) in a blinded fashion. Intraobserver and interobserver reliabilities were assessed by calculating kappa statistics.

RESULTS

Grade I degeneration was observed in 27 discs (9.0%); grade II, in 56 (18.7%); grade III, in 124 (41.3%); grade IV, in 67 (22.3%); and grade V, in 26 (8.7%) discs. Kappa coefficients for intraobserver and interobserver agreements ranged from substantial to excellent (intraobserver, 0.907 to 0.950 and interobserver, 0.730 to 0.826). Complete agreement was obtained, on an average, in 72.1% of the discs. A difference of 1, 2, and 3 grades was observed in 22.4%, 3.3%, and 0.2% discs, respectively.

CONCLUSIONS

This grading system is comprehensive and easily applicable with sufficient reproducibility. It can be used as a common nomenclature for research and discussions.