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

Relationship between Initial Telomere Length, Initial Telomerase Activity, Age, and Replicative Capacity of Nucleus Pulposus Chondrocytes in Human Intervertebral Discs: What Is a Predictor of Replicative Potential?

There is evidence that telomere length (TL), telomerase activity (TA), and age are related to the replicative potential of human nucleus pulposus chondrocytes (NPCs). However, it has not yet been established if any of these factors can serve as predictors of the replicative potential of NPCs. To establish predictors of the replicative potential of NPCs, we evaluated potential relationships between replicative capacity of NPCs, initial TL (telomere length at the first passage), initial TA (telomerase activity at the first passage), and age. Nucleus pulposus specimens were obtained from 14 patients of various ages undergoing discectomy. NPCs were serially cultivated until the end of their replicative lifespans. Relationships among cumulative population doubling level (PDL), initial TL, initial TA, and age were analyzed. Initial TA was negatively correlated with age (r = -0.674, P = 0.008). However, no correlation between initial TL and age was observed. Cumulative PDL was also negatively correlated with age (r = -0.585, P = 0.028). Although the cumulative PDL appeared to increase with initial TL or initial TA, this trend was not statistically significant. In conclusion, age is the sole predictor of the replicative potential of human NPCs, and replicative potential decreases with age. Initial TL and initial TA are not predictors of replicative potential, and can serve only as reference values.

MRI evaluation of spontaneous intervertebral disc degeneration in the alpaca cervical spine

Animal models have historically provided an appropriate benchmark for understanding human pathology, treatment, and healing, but few animals are known to naturally develop intervertebral disc degeneration. The study of degenerative disc disease and its treatment would greatly benefit from a more comprehensive, and comparable animal model. Alpacas have recently been presented as a potential large animal model of intervertebral disc degeneration due to similarities in spinal posture, disc size, biomechanical flexibility, and natural disc pathology. This research further investigated alpacas by determining the prevalence of intervertebral disc degeneration among an aging alpaca population. Twenty healthy female alpacas comprised two age subgroups (5 young: 2-6 years; and 15 older: 10+ years) and were rated according to the Pfirrmann-grade for degeneration of the cervical intervertebral discs. Incidence rates of degeneration showed strong correlations with age and spinal level: younger alpacas were nearly immune to developing disc degeneration, and in older animals, disc degeneration had an increased incidence rate and severity at lower cervical levels. Advanced disc degeneration was present in at least one of the cervical intervertebral discs of 47% of the older alpacas, and it was most common at the two lowest cervical intervertebral discs. The prevalence of intervertebral disc degeneration encourages further investigation and application of the lower cervical spine of alpacas and similar camelids as a large animal model of intervertebral disc degeneration.

Osteogenic protein 1 does not stimulate a regenerative effect in cultured human degenerated nucleus pulposus tissue

Low back pain is a major cause of disability and is heavily associated with intervertebral disc degeneration. Osteogenic protein 1 (OP-1) is a growth factor that has shown potential to regenerate the intervertebral disc in human cells and animal models. However, high doses are required, presumably due to clearance from the tissue; controlled release may be a solution to this problem. In this study, we developed a preclinical, pathophysiological human tissue explant culture model of degenerated nucleus pulposus (NP). The NP explants were cultured for 28 days and injected with 100 µg OP-1 as a bolus, or with sustained-release biodegradable microspheres loaded with 16 or 1.6 µg OP-1. After culture, the tissue explants were analysed for biochemical content [water, sulphated glycosaminoglycans (GAGs), hydroxyproline and DNA], histology, cell viability and gene expression (disc matrix anabolic and catabolic markers). Untreated degenerated NP explants lost some of their GAG content when cultured for 4 weeks, but maintained other tissue constituents. Gene expression levels were close to native values. A bolus injection of OP-1 partially restored GAG content to the native level in half of the donors, while the sustained release of OP-1 did not affect the NP explants. No effect of treatment was observed on anabolic or catabolic gene expression at day 28. These results demonstrated that the regenerative potential of OP-1 is donor dependent, and only at very high doses. This questions the clinical use of OP-1 as a regenerative agent, as these high doses may increase the incidence of complications. Copyright © 2015 John Wiley & Sons, Ltd.

Semaphorin 3A: A Potential Target for Low Back Pain

Low back pain is a common disorder. Pathological innervation and intervertebral disc degeneration are two major factors associated with this disease. Semaphorin 3A, originally known for its potent inhibiting effect on axonal outgrowth, is recently found to correlate with disease activity and histological features in some skeletal disorders. Based on its effects on innervation and vascularization, as well as enzyme secretion, we presume that semaphorin 3A may act as a potential target for low back pain.

Effect of Lumbar Disc Degeneration and Low-Back Pain on the Lumbar Lordosis in Supine and Standing: A Cross-Sectional MRI Study

STUDY DESIGN

Cross-sectional study.

OBJECTIVE

To examine the influence of low-back pain (LBP) and lumbar disc degeneration (LDD) on the lumbar lordosis in weight-bearing positional magnetic resonance imaging (pMRI).

SUMMARY OF BACKGROUND DATA

The lumbar lordosis increases with a change of position from supine to standing and is known as an essential contributor to dynamic changes. However, the lordosis may be affected by disc degeneration and pain.

METHODS

Patients with LBP >40 on a 0 to 100 mm Visual Analog Scale (VAS) both during activity and rest and a sex and age-decade matching control group without LBP were scanned in the supine and standing position in a 0.25-T open MRI unit. LDD was graded using Pfirrmann's grading-scale. Subsequently, the L2-to-S1 lumbar lordosis angle (LA) was measured.

RESULTS

Thirty-eight patients with an average VAS of 58 (±13.8) mm during rest and 75 (±5.0) mm during activities, and 38 healthy controls were included. MRI findings were common in both groups, whereas, the summation of the Pfirrmann's grades (LDD-score) was significantly higher in the patients [(MD 1.44; 95% confidence intervals (CI) 0.80 to 2.10; P < 0.001]. The patients were less lordotic than the controls in both the supine (MD -6.4°; 95% CI -11.4 to -1.3), and standing position (MD -5.6°; 95% CI -10.7 to -0.7); however, the changes between the positions (ΔLA) were the same (MD 0.8°; 95% CI -1.8 to 3.3). Using generalized linear model the LDD-score was associated with age (P < 0.001) for both groups. The LDD-score and ΔLA were negatively associated in the control group (P < 0.001), also after adjustments for gender and age (β-coefficient: -2.66; 95% CI -4.3 to -1.0; P = 0.002).

CONCLUSION

Patients may be less lordotic in both the supine and standing position, whereas, change in the lordosis between the positions may be independent of pain. Decreasing lordosis change seems to be associated with age-related increasing disc degeneration in healthy individuals.

LEVEL OF EVIDENCE

2.

TGF-β1 antagonizes TNF-α induced up-regulation of matrix metalloproteinase 3 in nucleus pulposus cells: role of the ERK1/2 pathway

Tumor necrosis factor-α (TNF-α) has been shown to have a catabolic effect on intervertebral disc degeneration (IVDD), including increasing MMP3 expression and subsequent extracellular matrix (ECM) degradation. In contrast, transforming growth factor-β1 (TGF-β1) has an anabolic effect on nucleus pulposus (NP) cells. However, the anti-catabolic effect of TGF-β1 under inflammatory condition is unknown. The aim of this study was to demonstrate whether TGF-β1 can reverse TNF-α-induced MMP3 increase in NP cells and to further investigate the underlying mechanisms. The transcriptional activity, gene expression, and protein levels of MMP3 were measured by luciferase reporter assay, qRT-PCR and western blot, respectively. TNF-α increased MMP3 expression in rat NP cells time and dose dependently. TGF-β1 could abolish TNF-α-mediated up-regulation of collagen I and MMP3 expression, and down-regulate aggrecan and collagen II expression. The ERK1/2 signaling pathway was activated after exposure to TGF-β1. Treatment with ERK1/2 inhibitors (PD98059 and U0126) abolished the antagonistic effect of TGF-β1 on TNF-α mediated catabolic responses. These findings provide novel evidence supporting the anti-catabolic role of TGF-β1 in IVDD, which is important for the potential clinical application of TGF-β1 in disc degenerative disorders.

Gender, BMI and T2 dependencies of glycosaminoglycan chemical exchange saturation transfer in intervertebral discs

PURPOSE

The purpose was to investigate the dependence of glycosaminoglycan chemical exchange saturation transfer (gagCEST) effect of lumbar intervertebral discs (IVD) on gender, body mass index and T2 value.

METHODS

T2 imaging and gagCEST imaging was performed in 34 healthy volunteers (17 males, 17 females) without low back pain at a 3T MRI system (Magnetom Trio, A Tim System, Siemens Healthcare, Erlangen, Germany). The body mass index was determined for each volunteer. The mean and standard deviation of MTRasym and T2 values were calculated for nucleus pulposus (NP) and annulus fibrosus (AF) as descriptive statistics for females and males. An unpaired student's t-test was applied in order to validate obtained differences. Pearson correlation was determined in order to reveal, if gagCEST effect and T2 values decrease with increasing body mass index (BMI). Pearson correlation analysis was additionally performed between gagCEST and T2 values.

RESULTS

GagCEST effect and T2 values were significantly higher in females compared to males [gagCEST effect (nucleus pulposus, females)=3.58±1.49%; gagCEST effect (nucleus pulosus, males)=3.01±1.63%, p-value (gagCEST effect, nucleus pulposus)=0.02); T2 (nucleus pulposus, females)=134.56±30.27 ms, T2 (nucleus pulposus, males)=122.35±27.64 ms, p-value (T2, nucleus pulposus)=0.01)]. Pearson correlation analysis showed a significant negative relation between BMI and gagCEST effect (nucleus pulposus: ρ=-0.16, p=0.03) and between BMI and T2 values (nucleus pulposus: ρ=-0.30, p<0.01). The correlation between gagCEST effect and T2-values was highly significant (nucleus pulposus: ρ=0.59, p<0.01).

CONCLUSIONS

Significantly lower gagCEST effects were found in males compared to females and with increased body mass index. The gagCEST effect was highly correlated with quantitative T2 imaging.

Translational challenges for the development of a novel nucleus pulposus substitute: Experimental results from biomechanical and in vivo studies

Nucleus pulposus replacement therapy could offer a less invasive alternative to restore the function of moderately degenerated intervertebral discs than current potentially destructive surgical procedures. Numerous nucleus pulposus substitutes have already been investigated, to assess their applicability for intradiscal use. Still, the current choice of testing methods often does not lead to efficient translation into clinical application. In this paper, we present the evaluation of a novel nucleus pulposus substitute, consisting of a hydromed core and an electrospun envelope. We performed three mechanical evaluations and an in vivo pilot experiment. Initially, the swelling pressure of the implant was assessed in confined compression. Next, we incorporated the implant into mechanically damaged caprine lumbar intervertebral discs to determine biomechanical segment behaviour in bending and torsion. Subsequently, segments were serially tested in native, damaged and repaired conditions under dynamic axial compressive loading regimes in a loaded disc culture system. Finally, nucleus pulposus substitutes were implanted in a live goat spine using a transpedicular approach. In confined compression, nucleus pulposus samples as well as implants showed some load-bearing capacity, but the implant exhibited a much lower absolute pressure. In bending and torsion, we found that the nucleus pulposus substitute could partly restore the mechanical response of the disc. During dynamic axial compression in the loaded disc culture system, on the other hand, the implant was not able to recover axial compressive behaviour towards the healthy situation. Moreover, the nucleus pulposus substitutes did not remain in place in the in vivo situation but migrated out of the disc area. From these results, we conclude that implants may mimic native disc behaviour in simple mechanical tests, yet fail in other, more realistic set-ups. Therefore, we recommend that biomaterials for nucleus pulposus replacement be tested in testing modalities of increasing complexity and in their relevant anatomical surroundings, for a more reliable prediction of clinical potential.

Impact of sagittal spinopelvic alignment on clinical outcomes after decompression surgery for lumbar spinal canal stenosis without coronal imbalance

OBJECT

The object of this study was to investigate correlations between sagittal spinopelvic alignment and improvements in clinical and quality-of-life (QOL) outcomes after lumbar decompression surgery for lumbar spinal canal stenosis (LCS) without coronal imbalance.

METHODS

The authors retrospectively reviewed data from consecutive patients treated for LCS with decompression surgery in the period from 2009 through 2011. They examined correlations between preoperative or postoperative sagittal vertical axis (SVA) and radiological parameters, clinical outcomes, and health-related (HR)QOL scores in patients divided according to SVA. Clinical outcomes were assessed according to Japanese Orthopaedic Association (JOA) and visual analog scale (VAS) scores. Health-related QOL was evaluated using the Roland-Morris Disability Questionnaire (RMDQ) and the JOA Back Pain Evaluation Questionnaire (JOABPEQ).

RESULTS

One hundred nine patients were eligible for inclusion in the study. Compared to patients with normal sagittal alignment prior to surgery (Group A: SVA < 50 mm), those with preoperative sagittal imbalance (Group B: SVA ≥ 50 mm) had significantly smaller lumbar lordosis and thoracic kyphosis angles and larger pelvic tilt. In Group B, there was a significant decrease in postoperative SVA compared with the preoperative SVA (76.3 ± 29.7 mm vs 54.3 ± 39.8 mm, p = 0.004). The patients in Group B with severe preoperative sagittal imbalance (SVA > 80 mm) had residual sagittal imbalance after surgery (82.8 ± 41.6 mm). There were no significant differences in clinical and HRQOL outcomes between Groups A and B. Compared to patients with normal postoperative SVA (Group C: SVA < 50 mm), patients with a postoperative SVA ≥ 50 mm (Group D) had significantly lower JOABPEQ scores, both preoperative and postoperative, for walking ability (preop: 36.6 ± 26.3 vs 22.7 ± 26.0, p = 0.038, respectively; postop: 71.1 ± 30.4 vs 42.5 ± 29.6, p < 0.001) and social functioning (preop: 38.7 ± 18.5 vs 30.2 ± 16.7, p = 0.045; postop: 67.0 ± 25.8 vs 49.6 ± 20.0, p = 0.001), as well as significantly higher postoperative RMDQ (4.9 ± 5.2 vs 7.9 ± 5.7, p = 0.015) and VAS scores for low-back pain (2.68 ± 2.69 vs 3.94 ± 2.59, p = 0.039).

CONCLUSIONS

Preoperative sagittal balance was not significantly correlated with clinical or HRQOL outcomes after decompression surgery in LCS patients without coronal imbalance. Decompression surgery improved the SVA value in patients with preoperative sagittal imbalance; however, the patients with severe preoperative sagittal imbalance (SVA > 80 mm) had residual imbalance after decompression surgery. Both clinical and HRQOL outcomes were negatively affected by postoperative residual sagittal imbalance.

Can specific loading through exercise impart healing or regeneration of the intervertebral disc?

BACKGROUND CONTEXT

Low back pain (LBP) is highly prevalent and presents an enormous cost both through direct health care and indirectly through significant work and production loss. Low back pain is acknowledged widely to be a multifactorial pathology with a variety of symptoms, dysfunctions, and a number of possible sources of pain. One source that has been suspected and evidenced for some time is the intervertebral disc. Some degree of disc degeneration is a physiologic process associated with aging, however, more severe degeneration and/or structural abnormality may be indicative of a pathologic process or injury and is more commonly present in those suffering from LBP. Much like other tissues (ie, muscle, bone, etc.), it has been suspected that there exists an optimal loading strategy to promote the health of the disc. Exercise is often prescribed for LBP and effectively reduces pain and disability. However, whether specific loading through exercise might plausibly heal or regenerate the intervertebral discs is unknown.

PURPOSE

To examine the effects of loading on regenerative processes in the intervertebral disc and consider the potential for specific exercise to apply loading to the lumbar spine to produce these effects.

STUDY DESIGN

A brief narrative literature review.

METHODS

Studies examining the effects of loading on the intervertebral discs were reviewed to examine the plausibility of using loading through exercise to induce regeneration or healing of the intervertebral disc.

RESULTS

Research from animal model studies suggests the existence of a dose-response relationship between loading and regenerative processes. Although high loading at high volumes and frequencies might accelerate degeneration or produce disc injury, high loading, yet of low volume and at low frequency appears to induce potentially regenerative mechanisms, including improvements in disc proteoglycan content, matrix gene expression, rate of cell apoptosis, and improved fluid flow and solute transport.

CONCLUSIONS

Research suggests a dose-response relationship between loading and disc regenerative processes and that the loading pattern typically used in the lumbar extension resistance exercise interventions (high load, low volume, and low frequency) might impart healing or regeneration of the intervertebral discs. Future research should examine an exercise intervention with in vivo measurement of changes in disc condition. This may provide further evidence for the "black box" of treatment mechanisms associated with exercise interventions.

BMP-2 and BMP-2/7 Heterodimers Conjugated to a Fibrin/Hyaluronic Acid Hydrogel in a Large Animal Model of Mild Intervertebral Disc Degeneration

Intervertebral disc (IVD) degeneration is etiologically associated with low back pain and is currently only treated in severe cases with spinal fusion. Regenerative medicine attempts to restore degenerated tissue by means of cells, hydrogels, and/or growth factors and can therefore be used to slow, halt, or reverse the degeneration of the IVD in a minimally invasive manner. Previously, the growth factors bone morphogenetic proteins 2 and 7 (BMP-2, -7) were shown to enhance disc regeneration, in vitro and in vivo. Since BMPs have only a short in vivo half-life, and to prevent heterotopic ossification, we evaluated the use of a slow release system for BMP-2 homodimers and BMP-2/7 heterodimers for IVD regeneration. BMP growth factors were conjugated to a fibrin/hyaluronic acid (FB/HA) hydrogel and intradiscally injected in a goat model of mild IVD degeneration to study safety and efficacy. Mild degeneration was induced in five lumbar discs of seven adult Dutch milk goats, by injections with the enzyme chondroitinase ABC. After 12 weeks, discs were treated with either FB/HA-hydrogel only or supplemented with 1 or 5 μg/mL of BMP-2 or BMP-2/7. BMPs were linked to the FB/HA hydrogels using a transglutaminase moiety, to be released through an incorporated plasmin cleavage site. After another 12 weeks, goats were sacrificed and discs were assessed using radiography, MRI T2* mapping, and biochemical and histological analyses. All animals maintained weight throughout the study and no heterotopic bone formation or other adverse effects were noted during follow-up. Radiographs showed significant disc height loss upon induction of mild degeneration. MRI T2* mapping showed strong and significant correlations with biochemistry and histology as shown before. Surprisingly, no differences could be demonstrated in any parameter between intervention groups. To our knowledge, this is the first large animal study evaluating BMPs conjugated to an FB/HA-hydrogel for the treatment of mild IVD degeneration. The conjugated BMP-2 and BMP-2/7 appeared safe, but no disc regeneration was observed. Possible explanations include too low dosages, short follow-up time, and/or insufficient release of the conjugated BMPs. These aspects should be addressed in future studies.

Inflammation in intervertebral disc degeneration and regeneration

Intervertebral disc (IVD) degeneration is one of the major causes of low back pain, a problem with a heavy economic burden, which has been increasing in prevalence as populations age. Deeper knowledge of the complex spatial and temporal orchestration of cellular interactions and extracellular matrix remodelling is critical to improve current IVD therapies, which have so far proved unsatisfactory. Inflammation has been correlated with degenerative disc disease but its role in discogenic pain and hernia regression remains controversial. The inflammatory response may be involved in the onset of disease, but it is also crucial in maintaining tissue homeostasis. Furthermore, if properly balanced it may contribute to tissue repair/regeneration as has already been demonstrated in other tissues. In this review, we focus on how inflammation has been associated with IVD degeneration by describing observational and in vitro studies as well as in vivo animal models. Finally, we provide an overview of IVD regenerative therapies that target key inflammatory players.

Bioluminescence-mediated longitudinal monitoring of adipose-derived stem cells in a large mammal ex vivo organ culture

Recently, ex vivo three-dimensional organ culture systems have emerged to study the physiology and pathophysiology of human organs. These systems also have potential as a translational tool in tissue engineering; however, this potential is limited by our ability to longitudinally monitor the fate and action of cells used in regenerative therapies. Therefore, we investigated luciferase-mediated bioluminescence imaging (BLI) as a non-invasive technique to continuously monitor cellular behavior in ex vivo whole organ culture. Goat adipose-derived stem cells (gADSCs) were transduced with either Firefly luciferase (Fluc) or Gaussia luciferase (Gluc) reporter genes and injected in isolated goat intervertebral discs (IVD). Luciferase activity was monitored by BLI for at least seven days of culture. Additionally, possible confounders specific to avascular organ culture were investigated. Gluc imaging proved to be more suitable compared to Fluc in monitoring gADSCs in goat IVDs. We conclude that BLI is a promising tool to monitor spatial and temporal cellular behavior in ex vivo organ culture. Hence, ex vivo organ culture systems allow pre-screening and pre-validation of novel therapeutic concepts prior to in vivo large animal experimentation. Thereby, organ culture systems can reduce animal use, and improve the speed of innovation by overcoming technological, ethical and financial challenges.

Do MRI findings identify patients with low back pain or sciatica who respond better to particular interventions? A systematic review

PURPOSE

Magnetic resonance imaging (MRI) can reveal a range of degenerative findings and anatomical abnormalities; however, the clinical importance of these remains uncertain and controversial. We aimed to investigate if the presence of MRI findings identifies patients with low back pain (LBP) or sciatica who respond better to particular interventions.

METHODS

MEDLINE, EMBASE and CENTRAL databases were searched. We included RCTs investigating MRI findings as treatment effect modifiers for patients with LBP or sciatica. We excluded studies with specific diseases as the cause of LBP. Risk of bias was assessed using the criteria of the Cochrane Back Review Group. Each MRI finding was examined for its individual capacity for effect modification.

RESULTS

Eight published trials met the inclusion criteria. The methodological quality of trials was inconsistent. Substantial variability in MRI findings, treatments and outcomes across the eight trials prevented pooling of data. Patients with Modic type 1 when compared with patients with Modic type 2 had greater improvements in function when treated by Diprospan (steroid) injection, compared with saline. Patients with central disc herniation when compared with patients without central disc herniation had greater improvements in pain when treated by surgery, compared with rehabilitation.

CONCLUSIONS

Although individual trials suggested that some MRI findings might be effect modifiers for specific interventions, none of these interactions were investigated in more than a single trial. High quality, adequately powered trials investigating MRI findings as effect modifiers are essential to determine the clinical importance of MRI findings in LBP and sciatica (

PROSPERO

CRD42013006571).

Phenotype profiling of Modic changes of the lumbar spine and its association with other MRI phenotypes: a large-scale population-based study

BACKGROUND CONTEXT

Modic changes (MC) are associated with low back pain. They represent vertebral endplate and adjacent vertebral marrow changes on magnetic resonance imaging (MRI), classified into three types. Because of small sample sizes, patient cohorts, and limited phenotype assessment, the morphology and involvement of MC and their association with other spinal phenotypes remain speculative.

PURPOSE

We addressed and proposed a phenotypic profiling of MC and their relationship with lumbar MRI phenotypes in a large-scale population-based study.

STUDY DESIGN/SETTING

A cross-sectional study of the Hong Kong Disc Degeneration Cohort.

PATIENT SAMPLE

The study population consisted of 1,546 Southern Chinese volunteers.

OUTCOME MEASURES

Topographical and morphological dimensions of MC, presence of disc degeneration (DD) and displacement, and Schmorl nodes were evaluated.

METHODS

Axial T1-weighted and sagittal T2-weighted MRIs (3T) were assessed.

RESULTS

Females were 62.4% (mean age, 49 years). The overall prevalence of MC was 21.9% (6.3% Type I and 15.5% Type II). Of all MC, 76% were located at the two lowest lumbar levels. Modic changes at the two lowest lumbar levels were more commonly located laterally (p<.001), less commonly anteriorly (p<.001), and were more extensive horizontally (p=.006) but not in vertical height compared with the upper levels. Type I MC were less common in the anterior part (p=.022), larger in size (height p=.004), and affected more likely the whole horizontal plane (p=.016) than Type II MC. Modic changes were associated with disc displacement, Schmorl nodes, and DD at the affected level (all p<.001), and the strength of association increased with the size of the lesion. Type I MC were associated more strongly with disc displacement (p=.008) and DD (p=.022) than Type II MC.

CONCLUSIONS

Our large-scale MRI study is the first to definitely note that MC were size- and type-dependently significantly associated with disc pathology and endplate abnormalities. Our phenotype profiling of MC may have clinical utility.

Age and pro-inflammatory gene polymorphisms influence adjacent segment disc degeneration more than fusion does in patients treated for chronic low back pain

PURPOSE

Does lumbar fusion lead to accelerated adjacent segment disc degeneration (ASDD) or is it explained by genetics and aging? The influence of genetics on ASDD remains to be explored. This study assesses whether the disc space height adjacent to a fused segment is associated with candidate gene single nucleotide polymorphisms (SNPs).

METHODS

Patients with low back pain from four RCTs (N = 208 fusion; 77 non-operative treatment) underwent standing plain radiography and genetic analyses at 13 ± 4 years follow-up. Disc space height was measured using a validated computer-assisted distortion-compensated roentgen analysis technique and reported in standard deviations from normal values. Genetic association analyses included 34 SNPs in 25 structural, inflammatory, matrix degrading, apoptotic, vitamin D receptor and OA-related genes relevant to disc degeneration. These were analysed for their association with disc space height (after adjusting for age, gender, smoking, duration of follow-up and treatment group) first, separately, and then together in a stepwise multivariable model.

RESULTS

Two SNPs from the IL18RAP gene (rs1420106 and rs917997) were each associated with a lower disc space height at the adjacent level (B = -0.34, p = 0.04 and B = -0.35, p = 0.04, respectively) and the MMP-9 gene SNP rs20544 was associated with a greater disc space height (B = 0.35, p = 0.04). Age (p < 0.001) and fusion (p < 0.008) were also significant variables in each analysis. The total explained variance in disc space height was for each SNP model 13-14 %, with 11-12 % of this being accounted for by the given SNP, 64-67 % by age and 19-22 % by fusion. In the multivariable regression analysis (with nine SNPs selected for entry, along with the covariates) the total explained variance in disc space height was 23 %, with the nine SNPs, age and fusion accounting for 45, 45 and 7 % of this, respectively.

CONCLUSIONS

Age was the most significant determinant of adjacent segment disc space height followed by genetic factors, specifically inflammatory genes. Fusion explained a statistically significant but small proportion of the total variance. Much of the variance remained to be explained.

Low Back Pain: A Biomechanical Rationale Based on "Patterns" of Disc Degeneration

STUDY DESIGN

A nonlinear finite element study of a lumbar spine with different "patterns" of multilevel intervertebral disc degeneration.

OBJECTIVE

To determine how different patterns of multilevel disc degeneration influence the biomechanical behavior of the lumbar spine.

SUMMARY OF BACKGROUND DATA

Because of the complex etiology of low back pain, it is often difficult to identify the specific factors that contribute to the symptoms of a particular patient. Disc degeneration is associated with the development of low back pain, but its presence is not always synonymous with symptoms. However, studies have suggested that "patterns" of disc degeneration may provide insight into such pain generation rather than the overall presence of degenerative changes. Specifically, individuals with contiguous multilevel disc degeneration have been shown to exhibit higher presence and severity of low back pain than patients with skipped-level disc degeneration (i.e., healthy discs located in between degenerated discs).

METHODS

In this study, the biomechanical differences between these patterns were analyzed using a nonlinear finite element model of the lumbar spine. Thirteen separate "patterns" of disc degeneration were evaluated using the model and simulated under normal physiological loading conditions in each of the primary modes of spinal motion.

RESULTS

The results showed that stresses and forces of the surrounding ligaments, facets, and pedicles at certain vertebral levels of the spine were generally lower in skipped-level disc degeneration cases than in the contiguous multilevel disc degenerations cases even when the skipped level contained more degenerated discs.

CONCLUSION

To our knowledge, this is the first study to illustrate the biomechanics of specific patterns of disc degeneration of the lumbar spine. Using a multilevel disc degeneration model, our study provides insights as to why various patterns of disc degeneration throughout the lumbar spine may affect motion and soft tissue structures as well that may have bearing in the clinical pathway of pain generation.

LEVEL OF EVIDENCE

N/A.

ISSLS Prize Winner: Vertebral Endplate (Modic) Change is an Independent Risk Factor for Episodes of Severe and Disabling Low Back Pain

STUDY DESIGN

Longitudinal cohort study of twins representative of the general population.

OBJECTIVE

To assess the relationship between Modic change (MC) and severe, disabling low back pain (LBP), features of intervertebral disc degeneration (DD) and incident MC during 10-year follow-up.

SUMMARY OF BACKGROUND DATA

MC describes vertebral endplate and bone marrow lesions visible on magnetic resonance imaging (MRI). MC has been associated with DD. It remains unclear whether MC causes LBP independently or through association with DD. Moreover, association of MC with severe, disabling LBP is uncertain.

METHODS

Volunteers were recruited from the TwinsUK register to MRI and interview between 1996 and 2000 with a subset attending for follow-up a decade later. MC, DD (evaluated by loss of disc height and signal intensity, presence of disc bulge and anterior osteophytes) and Schmorl's nodes (SN) were determined on T2-weighted lumbar MR scans.

RESULTS

Complete data were available for 823 subjects at baseline and 429 at follow-up. Mean age at baseline was 54.0 years (range 32-70) with 96% females. The prevalence of MC was 32.2% at baseline and 48.7% at follow-up. Subjects with MC were older (P < 0.001) and more overweight (BMI: P = 0.026, weight: P < 0.001). At both baseline and follow-up, more subjects reporting severe LBP demonstrated MC (subjects with MC vs. without MC: 35.0% vs. 16.4% respectively, P < 0.001 at baseline; and 35.1% vs. 20.0% respectively, P < 0.001 at follow-up). In multivariable analyses, MC remained significantly associated with episodes of severe, disabling LBP (OR 1.58; 95% CI 1.04-2.41) after adjustment for age, BMI, DD, and SN at baseline. Loss of disc height and disc signal intensity were independently associated with prevalent MC at baseline, and disc height and disc bulge with incident MC during follow-up.

CONCLUSION

MC is an independent risk factor for episodes of severe and disabling LBP in middle-aged women. These observations support further work aimed at identifying the precise histology underlying MC.

LEVEL OF EVIDENCE

2.

The prevalence of degenerative or incidental findings in the lumbar spine of pediatric patients: a study using magnetic resonance imaging as a screening tool

PURPOSE

Several studies using magnetic resonance imaging (MRI) to evaluate the lumbar spine in adults have shown a large prevalence of degenerative changes in asymptomatic subjects; however, studies in pediatric patients are scarce. Those studies have suggested a lower rate of degenerative findings in adolescents than in adults, but the actual prevalence of MRI findings in the pediatric population has not yet been determined. We aimed to determine the prevalence of degenerative changes in the lumbar spine of pediatric patients using abdominal and pelvic MRI as the screening tool.

METHODS

We studied 103 patients (mean age 6.6 years) who were evaluated with abdominal and pelvic MRI for indications that were not spine related. The entire lumbo-sacral spine was evaluated to detect the presence of disc degeneration (DD), disc displacement, anular rupture with high-intensity zone (HIZ) and Modic changes.

RESULTS

In our population, 10.7 % [4.9-16.5] had at least one disc classified as Pfirrmann 2, and no patients presented discs classified as Pfirrmann 3, 4 or 5; patients exhibiting discs classified as Pfirrmann 2 were significantly older than patients who had only Pfirrmann 1 discs. The prevalence of disc bulging was 1 % [0-2.9]. No patients presented disc herniation (including protrusion or extrusions); additionally, no patients exhibited HIZ or Modic changes.

CONCLUSIONS

Incidental findings related to DD are very uncommon at this early age, in contrast to findings described in adults or later in adolescence.

Mechanics and biology in intervertebral disc degeneration: a vicious circle

Intervertebral disc degeneration is a major cause of low back pain. Despite its long history and large socio-economical impact in western societies, the initiation and progress of disc degeneration is not well understood and a generic disease model is lacking. In literature, mechanics and biology have both been implicated as the predominant inductive cause; here we argue that they are interconnected and amplify each other. This view is supported by the growing awareness that cellular physiology is strongly affected by mechanical loading. We propose a vicious circle of mechanical overloading, catabolic cell response, and degeneration of the water-binding extracellular matrix. Rather than simplifying the disease, the model illustrates the complexity of disc degeneration, because all factors are interrelated. It may however solve some of the controversy in the field, because the vicious circle can be entered at any point, eventually leading to the same pathology. The proposed disease model explains the comparable efficacy of very different animal models of disc degeneration, but also helps to consider the consequences of therapeutic interventions, either at the cellular, material or mechanical level.

Cervical Disc Protrusion Correlates With the Severity of Cervical Disc Degeneration: A Cross-Sectional Study of 1211 Relatively Healthy Volunteers

STUDY DESIGN

Cross-sectional study.

OBJECTIVE

The purposes of this study were (1) to investigate the frequency and degree of cervical disc degeneration and protrusion on cervical spine magnetic resonance (MR) images and (2) to analyze the correlation between the severity of disc degeneration and disc protrusion.

SUMMARY OF BACKGROUND DATA

Cervical disc degenerative changes or protrusion is commonly observed on MR images in healthy subjects. However, there are few large-scale studies, and the frequency and range of these findings in healthy subjects have not been clarified. Moreover, there are no reports regarding the correlation between cervical disc degeneration and disc protrusion.

METHODS

Cervical disc degeneration and protrusion were prospectively measured using magnetic resonance imaging in 1211 relatively healthy volunteers. These included at least 100 males and 100 females in each decade of life between the 20s and the 70s. Cervical disc degeneration was defined according to the modified Pfirrmann classification system, and the amount of disc protrusion was evaluated using the anteroposterior diameter of disc protrusion on sagittal MR image.

RESULTS

Mild disc degeneration was very common, including 98.0% of both sexes in their 20s. The severity of cervical disc degeneration significantly increased with age in both sexes at every level. The disc degeneration predominantly occurred at C5-C6 and C6-C7. The difference between sexes was not significant except for individuals in their 50s. The average anteroposterior diameter of disc protrusion increased with aging, especially from the 20s to the 40s. The anteroposterior diameter of disc protrusion increased with a progression in the disc degeneration grade.

CONCLUSION

Cervical disc degeneration and protrusion were frequently observed in healthy subjects even in their 20s and deteriorated with age. Cervical disc protrusion was significantly correlated with cervical disc degeneration, and spatial cervical disc protrusion was affected by biochemical degenerative changes as observed on MR images.

LEVEL OF EVIDENCE

2.

Differentiation of Human Ligamentum Flavum Stem Cells Toward Nucleus Pulposus-Like Cells Induced by Coculture System and Hypoxia

STUDY DESIGN

Human ligamentum flavum (LF)-derived stem cells (LFSCs) and nucleus pulposus cells (NPCs) were cocultured under normoxia or hypoxia.

OBJECTIVE

To isolate and identify human LFSCs and determine whether they can differentiate into NPCs when cocultured with NPCs under hypoxia.

SUMMARY OF BACKGROUND DATA

Mesenchymal stem cell (MSC)-based therapies have been proposed as a biological treatment for intervertebral disc degeneration. MSCs derived from various tissues are leading candidates for cell-based therapies, but such cells have not been reported in LF.

METHODS

LF cells were isolated from patient samples and cultured using culture flasks coated with fibronectin, and their identity was confirmed using flow cytometry. The cells were induced to differentiate into osteoblasts, chondrocytes, and adipocytes, and their morphology, immunophenotype, cell proliferation capacity, cell cycle, and expression of stem cell-specific genes were compared with those of bone marrow-MSCs (BM-MSCs) derived from the same patients. NPCs and LFSCs were cocultured in 1-μm-pore-size insert transwell-culture systems under hypoxia (2% O2) or normoxia. CD24 expression was measured by flow cytometry and confocal microscopy assay. On day 14, reverse transcription-polymerase chain reaction was used for comparing the expression of chondrogenic genes (Sox-9, collagen-II, aggrecan) and novel marker genes (KRT19, CA12, FOXF1, HIF-1α) between the 2 groups.

RESULTS

LFSCs were obtained using the fibronectin differential-adhesion assay. The morphology of LFSCs was altered, and their immunophenotype, multilineage induction, cell proliferation capacity, cell cycle, and stem cell-specific gene expression were closely related-but not identical-to BM-MSCs, CD24 expression was highly significant in the differentiated LFSCs. RT/Real-time polymerase chain reaction revealed that compared with LFSCs grown under normoxia, hypoxia-treated LFSCs expressed higher levels of Sox-9, collagen-II, aggrecan, KRT19, CA12, and HIF-1α genes except FOXF1.

CONCLUSION

Stem cells were identified in human LF, and LFSCs cocultured with NPCs were successfully differentiated into NP-like cells under hypoxia. This potentially provides new cell candidates for cell-based regenerative medicine and tissue engineering.

LEVEL OF EVIDENCE

N/A.

Prevalence and pattern of radiographic intervertebral disc degeneration in Vietnamese: a population-based study

Intervertebral disc degeneration (IDD) is one of the most common skeletal disorders, yet few data are available in Asian populations. We sought to assess the prevalence and pattern of radiographic IDD in a Vietnamese population. This population-based cross-sectional investigation involved 170 men and 488 women aged ≥40 years, who were randomly sampled from the Ho Chi Minh City (Vietnam). Anthropometric data, clinical history and self-reported back and neck pain were ascertained by a questionnaire. Plain radiographs (from the cervical spine, thoracic spine to the lumbar spine) were examined for the presence of disc space narrowing and/or osteophytosis using the Kellgren-Lawrence (KL) grading system. The presence of radiographic IDD was defined if the KL grade was 2 or greater in at least one disc. The prevalence of radiographic IDD was 62.4% (n = 106) in men and 54.7% (n = 267) in women. The most frequently affected site was the lumbar spine with prevalence being 50.6 and 43.2% in men and women, respectively. The prevalence of IDD increased with advancing age: 18.8% among those aged 40-49 years, and increased to 83.4% in those aged ≥60 years. Self-reported neck pain and lower back pain were found in 30 and 44% of individuals, respectively. There was no statistically significant association between self-reported neck pain and cervical spine OA. These data suggest that radiographic IDD is highly prevalent in the Vietnamese population, and that self-reported back pain is not a sensitive indicator of IDD.

Prevention of occupational Back Pain

This paper reviews scientific research on occupational back pain and focuses on prevention of this problem. It discusses some of the challenges of translating the evidence of this multi-factorial condition into policy. Medical science is currently unable to clearly distinguish between back pain caused by work and that possibly due to other causes but which affects the individual's capacity to work. Back pain affects the vast majority of people at some point in their lives and is very costly to both the health care system and the industry. Evidence suggests that heavy lifting, driving, and vibration of the whole body are linked to occupational back pain. Once the risk factors for occupational back pain are identified, an otherwise chronic and disabling condition can be prevented in the majority of patients. As explained in this article, three levels of prevention for occupational back pain have been reported as effective. Failure to implement preventive measures may lead to a high incidence of occupational back pain.

MRI evaluation of lumbar disc degenerative disease

INTRODUCTION

Lower back pain secondary to degenerative disc disease is a condition that affects young to middle-aged persons with peak incidence at approximately 40 y. MRI is the standard imaging modality for detecting disc pathology due to its advantage of lack of radiation, multiplanar imaging capability, excellent spinal soft-tissue contrast and precise localization of intervertebral discs changes.

AIMS AND OBJECTIVE

To evaluate the characterization, extent, and changes associated with the degenerative lumbar disc disease by Magnetic Resonance Imaging.

STUDY DESIGN

Cross-sectional and observational study.

MATERIALS AND METHODS

A total 109 patients of the lumbar disc degeneration with age group between 17 to 80 y were diagnosed & studied on 1.5 Tesla Magnetic Resonance Imaging machine. MRI findings like lumbar lordosis, Schmorl's nodes, decreased disc height, disc annular tear, disc herniation, disc bulge, disc protrusion and disc extrusion were observed. Narrowing of the spinal canal, lateral recess and neural foramen with compression of nerve roots observed. Ligamentum flavum thickening and facetal arthropathy was observed.

RESULT

Males were more commonly affected in Degenerative Spinal Disease & most of the patients show loss of lumbar lordosis. Decreased disc height was common at L5-S1 level. More than one disc involvement was seen per person. L4 - L5 disc was the most commonly involved. Annular disc tear, disc herniation, disc extrusion, narrowing of spinal canal, narrowing of lateral recess, compression of neural foramen, ligamentum flavum thickening and facetal arthropathy was common at the L4 -L5 disc level. Disc buldge was common at L3 - L4 & L4 - L5 disc level. Posterior osteophytes are common at L3 - L4 & L5 -S1 disc level. L1- L2 disc involvement and spondylolisthesis are less common.

CONCLUSION

Lumbar disc degeneration is the most common cause of low back pain. Plain radiograph can be helpful in visualizing gross anatomic changes in the intervertebral disc. But, MRI is the standard imaging modality for detecting disc pathology due to its advantage of lack of radiation, multiplanar imaging capability, excellent spinal soft-tissue contrast and precise localization of intervertebral discs changes.

The association of combination of disc degeneration, end plate signal change, and Schmorl node with low back pain in a large population study: the Wakayama Spine Study

BACKGROUND CONTEXT

Disc degeneration (DD) reportedly causes low back pain (LBP) and is often observed concomitantly with end plate signal change (ESC) and/or Schmorl node (SN) on magnetic resonance imaging.

PURPOSE

The purpose of this study was to examine the association between DD and LBP, considering ESC and/or SN presence, in a large population study.

STUDY DESIGN/SETTING

Cross-sectional population-based study in two regions of Japan.

PATIENT SAMPLE

Of 1,011 possible participants, data from 975 participants (324 men, 651 women; mean age, 66.4 years; range, 21-97 years) were included.

OUTCOME MEASURES

Prevalence of DD, ESC, and SN alone and in combination in the lumbar region and the association of these prevalence levels with LBP.

METHODS

Sagittal T2-weighted images were used to assess the intervertebral spaces between L1-L2 and L5-S1. Disc degeneration was classified using the Pfirrmann classification system (grades 4 and 5 indicated degeneration); ESC was defined as a diffuse high signal change along either area of the end plate, and SN was defined as a small well-defined herniation pit with a surrounding wall of hypointense signal. Logistic regression analysis was used to determine the odds ratios (ORs) and confidence intervals (CIs) for LBP in the presence of radiographic changes in the lumbar region and at each lumbar intervertebral level, compared with patients without radiographic change, after adjusting for age, body mass index, and sex.

RESULTS

The prevalence of lumbar structural findings was as follows: DD alone, 30.4%; ESC alone, 0.8%; SN alone, 1.5%; DD and ESC, 26.6%; DD and SN, 12.3%; and DD, ESC, and SN, 19.1%. These lumbar structural findings were significantly associated with LBP in the lumbar region overall, as follows: DD, ESC, and SN, OR 2.17, 95% CI 1.2-3.9; L1-L2, OR 6.00, 95% CI 1.9-26.6; L4-L5, OR 2.56, 95% CI 1.4-4.9; and L5-S1, OR 2.81, 95% CI 1.1-2.3. The combination of DD and ESC was significantly associated with LBP as follows: L3-L4, OR 2.43, 95% CI 1.5-4.0; L4-L5, OR 1.82, 95% CI 1.2-2.8; and L5-S1, OR 1.60, 95% CI 1.1-2.3.

CONCLUSIONS

Our data suggest that DD alone is not associated with LBP. By contrast, the combination of DD and ESC was highly associated with LBP.

Diagnostic capability of low- versus high-field magnetic resonance imaging for lumbar degenerative disease

STUDY DESIGN

Cohort study.

OBJECTIVE

To investigate the diagnostic capability of low-field magnetic resonance imaging (MRI) compared with high-field MRI for degenerative disease of the lumbar spine.

SUMMARY OF BACKGROUND DATA

Low-field MRI has several advantages over high-field magnetic resonance systems (easier installation, lower purchase, and maintenance cost). The diagnostic capability of low-field MRI for degenerative disease of the lumbar spine has not been compared with that of high-field MRI.

METHODS

Hundred patients (mean age: 56.3 yr, range: 32-80; F:M = 59:41) with neurogenic claudication or sciatica were studied. All patients underwent MRI of the lumbar spine on both low-field (0.25T) and high-field (1.5T or 3.0T) magnetic resonance systems. Intervertebral disc herniation, central canal, lateral recess, and exit foraminal stenosis as well as nerve root compression at L3-L4, L4-L5, and L5-S1 were evaluated by 2 radiologists for both low- and high-field systems using established reliable grading systems.

RESULTS

There was excellent agreement between low- and high- field MRI with regard to grading the presence and severity of disc herniation (r = 0.92-0.94; P < 0.05), central canal stenosis (r = 0.89-0.91; P < 0.05), lateral recess stenosis (r = 0.81-0.87; P < 0.05), and exit foramen stenosis (r = 0.81-0.89; P < 0.05). Descending or exiting nerve root compression occurred in 52% of patients at L3-L4, L4-L5, or L5-S1 levels, with good agreement between low-field and high-field MRI (r = 0.71-0.76; P < 0.05) for nerve root compression.

CONCLUSION

Excellent reliability between low- and high- field MRI was found for most features of lumbar disc degeneration, with good agreement for nerve root compression. 0.25T MRI was more susceptible to motion artifact, probably due to longer scanning time.

LEVEL OF EVIDENCE

3.

The Influence of Lumbar Spinal Subtype on Lumbar Intervertebral Disc Degeneration in Young and Middle-Aged Adults

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

To identify whether an in vivo correlation exists between lumbar spinal subtype (LSS) and lumbar disc degeneration (LDD) in young adults.

SUMMARY OF BACKGROUND DATA

Lumbar disc degeneration has largely been ascribed to biomechanical and structural alterations to the disc, which are attributed to aging and pathological physical loading. Sagittal alignment in the asymptomatic spine has also been considered. A biomechanical study by Roussouly and Pinheiro-Franco proposed level-specific patterns in LDD. To date, no in vivo correlation between the LSS and LDD has been established.

METHODS

The authors screened 608 consecutive patients over 5.3 years. Lumbar spinal subtype and pelvic parameters were collected from standing lumbar radiographs and were categorized using the classification of Roussouly and Pinheiro-Franco. Lumbar disc degeneration at all lumbar intervertebral levels was classified using criteria of Pfirrmann et al. A stratified disc degeneration score was derived for each patient. Lumbar disc degeneration in type I, II, and IV LSS was compared using chi-square test. Pelvic incidence was correlated with stratified disc degeneration score using Spearman R, to determine whether a high PI was protective against LDD. Statistical significance was accepted at p < .05.

RESULTS

A total of 139 patients were included, with 91 females and a mean age of 32.6 years (range, 13-49 years). For LSS grades I to IV, there were 10 (7.3%), 43 (30.9%), 50 (35.9%), and 36 (25.9%) patients, respectively. The proportion of high-grade (Pfirrmann grades IV and V) LDD increased distally toward the lower intervertebral levels, affecting 2.88%, 2.9%, 5%, 9.4%, 33.1%, and 54% of discs at each sequential lumbar level from T12-L1 to L5-S1, respectively. Age but not gender was statistically significant for higher-grade LDD (p < .0001 and p = .442, respectively). Pelvic incidence across all LSS grades was not significantly correlated with stratified disc degeneration score (Spearman R = 0.0933; p = .335). No LSS (type I-IV) reached statistical significance for a specific pattern of LDD.

CONCLUSIONS

In this study, LSS was not statistically significantly correlated with LDD, nor was a high pelvic incidence protective against LDD.

Analysis of chronic low back pain with magnetic resonance imaging T2 mapping of lumbar intervertebral disc

BACKGROUND

Magnetic resonance imaging (MRI) T2 mapping utilizes the T2 values for quantification of moisture content and collagen sequence breakdown. Recently, attempts at quantification of lumbar disc degeneration through MRI T2 mapping have been reported. We conducted an analysis of the relationship between T2 values of degenerated intervertebral discs (IVD) and chronic low back pain (CLBP).

METHODS

The subjects who had CLBP comprised 28 patients (15 male, 13 female; mean age 48.9 ± 9.6 years; range 22-60 years). All subjects underwent MRI and filled out the low back pain visual analog scale (VAS) and Japanese Orthopaedic Association Back Pain Evaluation Questionnaire (JOABPEQ). The disc was divided into the anterior annulus fibrosus (AF), the nucleus pulposus (NP), and the posterior AF, and each T2 value was measured. This study involved 25 asymptomatic control participants matched with the CLBP group subjects for gender and age (13 male, 12 female; mean age 43.8 ± 14.5 years; range 23-60 years). These subjects had no low back pain, and constituted the control group.

RESULTS

T2 values for IVD tended to be lower in the CLBP group than in the control group, and these values were significantly different within the posterior AF. The correlation coefficients between the VAS scores and T2 values of anterior AF, NP and posterior AF were r = 0.30, -0.15 and -0.50. The correlation coefficient between the JOABPEQ scores (low back pain) and T2 values of anterior AF, NP and posterior AF were r = -0.0041, 0.11 and 0.42. Similarly, the JOABPEQ scores (lumbar function) were r = -0.22, -0.12 and 0.57.

CONCLUSIONS

The results indicated a correlation between posterior AF degeneration and CLBP. This study suggests that MRI T2 mapping could be used as a quantitative method for diagnosing discogenic pain.

Stem cell therapy for intervertebral disc regeneration: obstacles and solutions

Intervertebral disc (IVD) degeneration is frequently associated with low back and neck pain, which accounts for disability worldwide. Despite the known outcomes of the IVD degeneration cascade, the treatment of IVD degeneration is limited in that available conservative and surgical treatments do not reverse the pathology or restore the IVD tissue. Regenerative medicine for IVD degeneration, by injection of IVD cells, chondrocytes or stem cells, has been extensively studied in the past decade in various animal models of induced IVD degeneration, and has progressed to clinical trials in the treatment of various spinal conditions. Despite preliminary results showing positive effects of cell-injection strategies for IVD regeneration, detailed basic research on IVD cells and their niche indicates that transplanted cells are unable to survive and adapt in the avascular niche of the IVD. For this therapeutic strategy to succeed, the indications for its use and the patients who would benefit need to be better defined. To surmount these obstacles, the solution will be identified only by focused research, both in the laboratory and in the clinic.

Adverse effects of stromal vascular fraction during regenerative treatment of the intervertebral disc: observations in a goat model

Stromal vascular fraction (SVF), an adipose tissue-derived heterogeneous cell mixture containing, among others, multipotent adipose stromal cells (ASCs) and erythrocytes, has proved beneficial for a wide range of applications in regenerative medicine. We sought to establish intervertebral disc (IVD) regeneration by injecting SVF intradiscally during a one-step surgical procedure in an enzymatically (Chondroitinase ABC; cABC) induced goat model of disc degeneration. Unexpectedly, we observed a severe inflammatory response that has not been described before, including massive lymphocyte infiltration, neovascularisation and endplate destruction. A second study investigated two main suspects for these adverse effects: cABC and erythrocytes within SVF. The same destructive response was observed in healthy goat discs injected with SVF, thereby eliminating cABC as a cause. Density gradient removal of erythrocytes and ASCs purified by culturing did not lead to adverse effects. Following these observations, we incorporated an extra washing step in the SVF harvesting protocol. In a third study, we applied this protocol in a one-step procedure to a goat herniation model, in which no adverse responses were observed either. However, upon intradiscal injection of an identically processed SVF mixture into our goat IVD degeneration model during a fourth study, the adverse effects surprisingly occurred again. Despite our quest for the responsible agent, we eventually could not identify the mechanism through which the observed destructive responses occurred. Although we cannot exclude that the adverse effects are species-dependent or model-specific, we advertise caution with the clinical application of autologous SVF injections into the IVD until the responsible agent(s) are identified.

Categorization of Pathology Causing Low Back Pain using Magnetic Resonance Imaging (MRI)

BACKGROUND

Low backache is the most common ailment flooding the orthopaedic clinic. Most of the population at least once seek medical attention for low back ache. Magnetic Resonance Imaging (MRI) is a non invasive, commonly used diagnosing modality and accurate in diagnosing pathology causing low back ache.

AIM

To classify and quantify the causes of low back pain referred to radiology department by MRI.

MATERIALS AND METHODS

Patients with back pain referred to radiology department were subjected to single MRI scan after ruling out any contraindications using the following sequences: T1W Turbo Spin Echo, T2W Turbo Spin Echo, Gradient-echo, Myelogram and short TI inversion recovery (STIR), in all imaging planes. Gadolinium enhanced T1W turbo spin echo sequence was used wherever necessary.

RESULTS

Data were analysed using Excel 2007, SPSS 14, Students t-test. Degenerative disc diseases were the commonest pathology followed by congenital and traumatic lesions. Neoplastic lesions were the least common. Commonest herniation type being the disc bulge (79%) followed by disc protrusion (15%), disc extrusion (6%) and disc sequestration (<1%). The posterolateral disc herniation as the commonest and foraminal the least. Sacralisation was the most common congenital spinal anomaly, followed by lumbar scoliosis and perineural cyst. There is no sex difference in disc protrusion but male preponderance in disc extrusion with subligmentous extrusion.

CONCLUSION

MRI is useful in classifying the spinal lesions which again influences the treatment modality and clinical outcome. Degenerative disc disease is the single most common category which accounts for most the Low Back Ache for which a preventing strategy should be drafted.

Comparison of modic changes in the lumbar and cervical spine, in 3167 patients with and without spinal pain

BACKGROUND CONTEXT

There are few comparisons of Modic changes (MCs) in the lumbar and cervical spine.

PURPOSE

Compare the prevalence of MCs in the lumbar and cervical spine, and determine how MC prevalence depends on spinal pain, age, disc degeneration, spinal level, and the presence or absence of kyphosis.

STUDY DESIGN

Retrospective clinical survey.

MATERIALS AND METHODS

Magnetic resonance images (MRIs) were compared from five patient groups: 1. 1223 patients with low-back pain/radiculopathy only; 2. 1023 patients with neck pain/radiculopathy only; 3. 497 patients with concurrent low-back and neck symptoms; 4. 304 asymptomatic subjects with lumbar MRIs; and 5. 120 asymptomatic subjects with cervical MRIs.

RESULTS

The prevalence of MCs was higher in those with spinal pain than in those without, both in the lumbar spine (21.0% vs 10.5%) and cervical spine (8.8% vs 3.3%). Type II MCs were most common and Type III were least common in all groups. The prevalence of lumbar MCs in people with back pain was little affected by the presence of concurrent neck pain, and the same was true for the prevalence of cervical MCs in people with neck pain with or without concurrent back pain. When symptomatic patients were reclassified into two groups (back pain, neck pain), the prevalence of lumbar MCs in people with back pain was greater than that of cervical MCs in people with neck pain. The prevalence of lumbar and cervical MCs increased with age, disc degeneration, (descending) spinal level, and increased kyphosis.

CONCLUSIONS

There is a significantly higher prevalence of MCs in patients with back and neck pain. The reported association with increased kyphosis (flat back) is novel.

Genetic and functional studies of the intervertebral disc: a novel murine intervertebral disc model

Intervertebral disc (IVD) homeostasis is mediated through a combination of micro-environmental and biomechanical factors, all of which are subject to genetic influences. The aim of this study is to develop and characterize a genetically tractable, ex vivo organ culture model that can be used to further elucidate mechanisms of intervertebral disc disease. Specifically, we demonstrate that IVD disc explants (1) maintain their native phenotype in prolonged culture, (2) are responsive to exogenous stimuli, and (3) that relevant homeostatic regulatory mechanisms can be modulated through ex-vivo genetic recombination. We present a novel technique for isolation of murine IVD explants with demonstration of explant viability (CMFDA/propidium iodide staining), disc anatomy (H&E), maintenance of extracellular matrix (ECM) (Alcian Blue staining), and native expression profile (qRT-PCR) as well as ex vivo genetic recombination (mT/mG reporter mice; AdCre) following 14 days of culture in DMEM media containing 10% fetal bovine serum, 1% L-glutamine, and 1% penicillin/streptomycin. IVD explants maintained their micro-anatomic integrity, ECM proteoglycan content, viability, and gene expression profile consistent with a homeostatic drive in culture. Treatment of genetically engineered explants with cre-expressing adenovirus efficaciously induced ex vivo genetic recombination in a variety of genetically engineered mouse models. Exogenous administration of IL-1ß and TGF-ß3 resulted in predicted catabolic and anabolic responses, respectively. Genetic recombination of TGFBR1^fl/fl explants resulted in constitutively active TGF-ß signaling that matched that of exogenously administered TGF-ß3. Our results illustrate the utility of the murine intervertebral disc explant to investigate mechanisms of intervertebral disc degeneration.

In vivo morphological features of human lumbar discs

Recent biomechanics studies have revealed distinct kinematic behavior of different lumbar segments. The mechanisms behind these segment-specific biomechanical features are unknown. This study investigated the in vivo geometric characteristics of human lumbar intervertebral discs. Magnetic resonance images of the lumbar spine of 41 young Chinese individuals were acquired. Disc geometry in the sagittal plane was measured for each subject, including the dimensions of the discs, nucleus pulposus (NP), and annulus fibrosus (AF). Segmental lordosis was also measured using the Cobb method.In general, the disc length increased from upper to lower lumbar levels, except that the L4/5 and L5/S1 discs had similar lengths. The L4/5 NP had a height of 8.6±1.3 mm, which was significantly higher than all other levels (P<0.05). The L5/S1 NP had a length of 21.6±3.1 mm, which was significantly longer than all other levels (P<0.05). At L4/5, the NP occupied 64.0% of the disc length, which was significantly less than the NP of the L5/S1 segment (72.4%) (P<0.05). The anterior AF occupied 20.5% of the L4/5 disc length, which was significantly greater than that of the posterior AF (15.6%) (P<0.05). At the L5/S1 segment, the anterior and posterior AFs were similar in length (14.1% and 13.6% of the disc, respectively). The height to length (H/L) ratio of the L4/5 NP was 0.45±0.06, which was significantly greater than all other segments (P<0.05). There was no correlation between the NP H/L ratio and lordosis. Although the lengths of the lower lumbar discs were similar, the geometry of the AF and NP showed segment-dependent properties. These data may provide insight into the understanding of segment-specific biomechanics in the lower lumbar spine. The data could also provide baseline knowledge for the development of segment-specific surgical treatments of lumbar diseases.

Genetic polymorphisms of interleukin-1 alpha and the vitamin d receptor in mexican mestizo patients with intervertebral disc degeneration

Intervertebral disc degeneration (IDD) is the most common diagnosis in patients with back pain, a leading cause of musculoskeletal disability worldwide. Several conditions, such as occupational activities, gender, age, and obesity, have been associated with IDD. However, the development of this disease has strong genetic determinants. In this study, we explore the possible association between rs1800587 (c.-949C>T) of interleukin-1 alpha (IL1A) and rs2228570 (c.2T>V) and rs731236 (c.1056T>C) of vitamin D receptor (VDR) gene polymorphisms and the development of IDD in northwestern Mexican Mestizo population. Gene polymorphisms were analyzed by polymerase chain reaction followed by restriction fragment length polymorphism, in two groups matched by age and gender: patients with symptomatic lumbar IDD (n = 100) and subjects with normal lumbar-spine MRI-scans (n = 100). Distribution of the mutated alleles in patients and controls was 27.0% versus 28.0% (P = 0.455) for T of rs1800587 (IL1A); 53.0% versus 58.0% (P = 0.183) for V of rs2228570 (VDR); and 18.0% versus 21.0% (P = 0.262) for C of rs731236 (VDR). Our results showed no association between the studied polymorphisms and IDD in this population. This is the first report on the contribution of gene polymorphisms on IDD in a Mexican population.

Prevalence of radiographic findings in individuals with chronic low back pain screened for a randomized controlled trial: secondary analysis and clinical implications

OBJECTIVE

The purpose of this study is to measure the prevalence of graded disc degeneration, spondylolisthesis, transitional segmentation, and the distribution of sacral slope in patients 21 to 65 years of age with chronic low back pain (CLBP).

METHODS

This retrospective study analyzed 247 digital lumbar radiographic series obtained during a randomized controlled trial of chiropractic patients with CLBP. Chronic low back pain was defined as pain in the low back lasting 12 weeks or longer. Radiographic findings of disc degeneration, spondylolisthesis, and lumbosacral transitional segmentation were graded by 2 authors using established classification criteria. Sacral slope was measured with a digital tool contained within imaging software.

RESULTS

Lumbosacral transitional segments graded I to IV (Castellvi classification) were present in 14% of cases. Lumbar disc degeneration was most prevalent at L3-4 (49%), followed by L4-5 (42%), L2-3 (41%), L5-S1 (37%), and L1-2 (29%). Isthmic spondylolisthesis was present in 5% of cases, with L5 the most common location. Degenerative spondylolisthesis demonstrated a prevalence of 18%, most commonly occurring at L4. The prevalence of degenerative spondylolisthesis was 51% for women aged 50 to 59 years and 24% for men in the same age range.

CONCLUSIONS

Moderate-severe disc degeneration, multilevel disc narrowing, and degenerative spondylolisthesis were common in individuals with CLBP with age more than 40 years. Isthmic spondylolisthesis was not more prevalent than what has been reported in other populations. Transitional segmentation was identified in a minority of participants, with some of these exhibiting accessory joints or fusion. Mean sacral slope in individuals with CLBP was not substantially different from mean slopes reported in other populations.

Magnetic resonance imaging evaluation of L5-s1 intervertebral disc degeneration in Japanese women

Study Design

Retrospective case series.

Purpose

To calculate the prevalence of L5-S1 intervertebral disc degeneration (IDD) by evaluating gynecological disease findings, obtained by pelvic magnetic resonance imaging (MRI), and reveal the risk factors for IDD by analyzing its relationship with age, sacral structure, body mass index (BMI), number of deliveries, and intrapelvic space-occupying lesions.

Overview of Literature

Age, obesity, height, smoking history, occupation, and lumbosacral structure are reportedly the main factors of lumbar IDD. However, in women, the relationship of IDD with obstetric and gynecological history is unclear.

Methods

The presence of L5-S1 IDD was evaluated on sagittal T2-weighted pelvic MRI during gynecological evaluations in 660 Japanese women. We measured the sacral table angle (STA), sacral kyphosis angle (SKA), and intrapelvic space-occupying lesion size. Age, height, weight, BMI, number of deliveries, lumbosacral structure, size of space-occupying lesions, and presence of uterine leiomyoma based on medical records were compared between the IDD-positive and IDD-negative groups.

Results

Lumbosacral IDD was observed in 405 cases (61.4%), and its prevalence increased with age. Differences in age, height, weight, BMI, and number of deliveries between the IDD-positive and -negative groups were significant, but differences in STA, SKA, and presence of uterine leiomyoma and space-occupying lesion size were not. Logistic regression analysis indicated that age, BMI, and STA were risk factors for lumbosacral IDD.

Conclusions

Age is the biggest risk factor for lumbosacral IDD in Japanese women, with BMI and STA also contributing to its development. However, SKA and obstetric and gynecological history were not significantly involved.