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

ROS: Crucial Intermediators in the Pathogenesis of Intervertebral Disc Degeneration

Excessive reactive oxygen species (ROS) generation in degenerative intervertebral disc (IVD) indicates the contribution of oxidative stress to IVD degeneration (IDD), giving a novel insight into the pathogenesis of IDD. ROS are crucial intermediators in the signaling network of disc cells. They regulate the matrix metabolism, proinflammatory phenotype, apoptosis, autophagy, and senescence of disc cells. Oxidative stress not only reinforces matrix degradation and inflammation, but also promotes the decrease in the number of viable and functional cells in the microenvironment of IVDs. Moreover, ROS modify matrix proteins in IVDs to cause oxidative damage of disc extracellular matrix, impairing the mechanical function of IVDs. Consequently, the progression of IDD is accelerated. Therefore, a therapeutic strategy targeting oxidative stress would provide a novel perspective for IDD treatment. Various antioxidants have been proposed as effective drugs for IDD treatment. Antioxidant supplementation suppresses ROS production in disc cells to promote the matrix synthesis of disc cells and to prevent disc cells from death and senescence in vitro. However, there is not enough in vivo evidence to support the efficiency of antioxidant supplementation to retard the process of IDD. Further investigations based on in vivo and clinical studies will be required to develop effective antioxidative therapies for IDD.

Micro-CT evaluation of asymmetrical ovine intervertebral disc height loss from surgical approach

PURPOSE

The primary goal of this study is to clearly define and evaluate new intervertebral disc height parameters in analysing the morphological pathology of disc degeneration for application in damage model and regeneration therapy development, as well as applying traditional variables to 3-D characterization methods.

METHODS

A posterolateral surgical approach was used to induce disc degeneration in an ovine model. At 12-months post-operation, sheep vertebral segments were removed and characterized using micro-CT to evaluate disc height parameters in regard to injury localization.

RESULTS

Statistically significant differences between the disc height loss of the left and right side of the disc, consistent with the lateral surgical approach used were seen using the modified average disc height method by Dabbs et al. However, convexity index and the newly proposed Cross Tilt Index did not conclusively demonstrate a difference.

CONCLUSION

Two-dimensional morphological evaluations can be applied in 3-D to provide a more complete picture of disc height loss for injury models. New 3-D parameters that are tailored to the type of surgical approach used should be investigated, with the 9-point system described herein providing a useful basis for derived values. Additionally, the surgical approach chosen when artificially injuring the disc can result in asymmetrical degeneration, as indicated by uneven disc height loss.

Advanced glycation end products regulate anabolic and catabolic activities via NLRP3-inflammasome activation in human nucleus pulposus cells

Intervertebral disc degeneration is widely recognized as a cause of lower back pain, neurological dysfunction and other musculoskeletal disorders. The major inflammatory cytokine IL‐1β is associated with intervertebral disc degeneration; however, the molecular mechanisms that drive IL‐1β production in the intervertebral disc, especially in nucleus pulposus (NP) cells, are unknown. In some tissues, advanced glycation end products (AGEs), which accumulate in NP tissues and promote its degeneration, increase oxidative stress and IL‐1β secretion, resulting in disorders, such as obesity, diabetes mellitus and ageing. It remains unclear whether AGEs exhibit similar effects in NP cells. In this study, we observed significant activation of the NLRP3 inflammasome in NP tissues obtained from patients with degenerative disc disease compared to that with idiopathic scoliosis according to results detected by Western blot and immunofluorescence. Using NP cells established from healthy tissues, our in vitro study revealed that AGEs induced an inflammatory response in NP cells and a degenerative phenotype in a NLRP3‐inflammasome‐dependent manner related to the receptor for AGEs (RAGE)/NF‐κB pathway and mitochondrial damage induced by mitochondrial reactive oxygen species (mtROS) generation, mitochondrial permeability transition pore (mPTP) activation and calcium mobilization. Among these signals, both RAGE and mitochondrial damage primed NLRP3 and pro‐IL‐1β activation as upstream signals of NF‐κB activity, whereas mitochondrial damage was critical for the assembly of inflammasome components. These results revealed that accumulation of AGEs in NP tissue may initiate inflammation‐related degeneration of the intervertebral disc via activation of the NLRP3 inflammasome.

Sequence variant at 8q24.21 associates with sciatica caused by lumbar disc herniation

Lumbar disc herniation (LDH) is common and often debilitating. Microdiscectomy of herniated lumbar discs (LDHsurg) is performed on the most severe cases to resolve the resulting sciatica. Here we perform a genome-wide association study on 4,748 LDHsurg cases and 282,590 population controls and discover 37 highly correlated markers associating with LDHsurg at 8q24.21 (between CCDC26 and GSDMC), represented by rs6651255[C] (OR=0.81; P=5.6 × 10⁻¹²) with a stronger effect among younger patients than older. As rs6651255[C] also associates with height, we performed a Mendelian randomization analysis using height polygenic risk scores as instruments to estimate the effect of height on LDHsurg risk, and found that the marker's association with LDHsurg is much greater than predicted by its effect on height. In light of presented findings, we speculate that the effect of rs6651255 on LDHsurg is driven by susceptibility to developing severe and persistent sciatica upon LDH.

Lumbar disc herniation (LDH) can cause persistent sciatica, and in some cases surgery is required to relieve symptoms. Here, the authors carry out a genome-wide association study using microdiscectomy as an indicator of severe LDH, and find a locus on chromosome 8 associated with this condition.

Low back pain, radiculopathy

Low back pain is a pervasive problem in the adult population. Most patients with low back pain will not require imaging as spontaneous recovery within 12 weeks is the rule. However, a small percentage of patients with low back pain will have serious underlying pathology requiring more intensive investigation. This chapter delineates the signs and symptoms related to potential serious underlying causes and discusses appropriate imaging modalities that should be utilized in patients with low back pain.

The usefulness of radiological grading scales to predict pain intensity, functional impairment, and health-related quality of life after surgery for lumbar degenerative disc disease

PURPOSE

The goal of this study is to determine the relationship of radiological grading scales of lumbar degenerative disc disease (DDD) with postoperative pain intensity, functional impairment, and health-related quality of life (HRQoL).

METHODS

Response to surgical treatment at 6 weeks (W6) on the visual analogue scale (VAS) for back and leg pain, Oswestry-Disability (ODI) and Roland-Morris Disability Index (RMDI), Timed Up and Go (TUG) test, EuroQol (EQ) 5D, and Short-Form Health-Survey (SF-12) physical component summary (PCS) was compared between patients with different Modic (MOD) and Pfirrmann (PFI) grades. Longitudinal outcomes at day 3 (D3), W6, 6 months (M6), and 1 year (Y1) were compared.

RESULTS

The study included 338 patients (mean age, 58.6 years), of which n = 202 (59.8%) had MOD 1-3 and n = 217 (64.2%) PFI 4-5 changes. Patients with MOD 1-3 were as likely as patients without MOD changes to be treatment-responders at W6 in terms of VAS leg pain, ODI, RMDI, TUG, EQ5D, and SF-12 PCS. Similarly, patients with PFI 4-5 were as likely as patients with PFI 1-3 changes to be treatment-responders at W6. Longitudinal outcomes were similar at D3, W6, M6, and Y1 between patients with and without MOD changes. Patients with PFI 4-5 fared similar to those with PFI 1-3 except for inferior HRQoL on the SF-12 PCS metric at Y1.

CONCLUSIONS

There was no distinct relationship between commonly used radiological grading scales of lumbar DDD with clinical outcome. Therefore, no prognosis should be made on the grounds of preoperative PFI and MOD classifications for patients undergoing spine surgery for lumbar DDD.

Does the fracture fragment at the anterior column in thoracolumbar burst fractures get enough attention?

Prospective cohort study. To evaluate whether failure of the fracture fragment at the anterior column reduction in thoracolumbar fracture has an influence on the final radiologic and clinical outcomes.Cervical teardrop fracture has caused wide concern in spinal surgery field. Although similar fracture fragment at the anterior column was also observed in thoracolumbar burst fractures, the conception of teardrop fracture in thoracolumbar fractures was rarely mentioned in the literature, let alone a study.Fifty patients who suffered from thoracolumbar burst fractures with a fracture fragment at the anterior column were prospectively analyzed. Twenty-seven patients in whom the fragments were reduced by posterior surgery, verified by postoperative X-ray or CT, were included in the reduced group, and 23 patients were included in the nonreduced group. Radiologic and clinical outcomes of both groups were compared after over 2 years follow-up.There was no significant difference regarding to Cobb angle, Oswestry Disability Index (ODI) score, and disc grade between the 2 groups preoperatively. At final follow-up, the mean angle of kyphosis was 13.91° ± 3.47° in the nonreduced group and 8.42° ± 2.07° in the reduced groups (P < 0.01). All fractures consolidated in the reduced group, but the nonreduced group revealed 3 cases with nonunion. Besides, the average Pfirrmann grade of degenerative disc adjacent to the fractured vertebral was 2.87 ± 1.18 in the nonreduced group, higher than 1.81 ± 0.62 in the reduced group (P < 0.01). The ODI score in the nonreduced group was 0.54 ± 0.13 and 0.36 ± 0.12 in the reduced group (P < 0.01).In the present study, failure reduction of the fracture fragment at the anterior column could result in poor radiologic and clinical outcomes of the thoracolumbar burst fractures treated with posterior surgery. Therefore, we recommend the surgeon should pay more attention to reducing the fracture fragment at the anterior column.

Biomechanics of the human intervertebral disc: A review of testing techniques and results

Many experimental testing techniques have been adopted in order to provide an understanding of the biomechanics of the human intervertebral disc (IVD). The aim of this review article is to amalgamate results from these studies to provide readers with an overview of the studies conducted and their contribution to our current understanding of the biomechanics and function of the IVD. The overview is presented in a way that should prove useful to experimentalists and computational modellers. Mechanical properties of whole IVDs can be assessed conveniently by testing 'motion segments' comprising two vertebrae and the intervening IVD and ligaments. Neural arches should be removed if load-sharing between them and the disc is of no interest, and specimens containing more than two vertebrae are required to study 'adjacent level' effects. Mechanisms of injury (including endplate fracture and disc herniation) have been studied by applying complex loading at physiologically-relevant loading rates, whereas mechanical evaluations of surgical prostheses require slower application of standardised loading protocols. Results can be strongly influenced by the testing environment, preconditioning, loading rate, specimen age and degeneration, and spinal level. Component tissues of the disc (anulus fibrosus, nucleus pulposus, and cartilage endplates) have been studied to determine their material properties, but only the anulus has been thoroughly evaluated. Animal discs can be used as a model of human discs where uniform non-degenerate specimens are required, although differences in scale, age, and anatomy can lead to problems in interpretation.

Contaminants in commercial preparations of 'purified' small leucine-rich proteoglycans may distort mechanistic studies

The present study reports the perplexing results that came about because of seriously impure commercially available reagents. Commercial reagents and chemicals are routinely ordered by scientists and expected to have been rigorously assessed for their purity. Unfortunately, we found this assumption to be risky. Extensive work was carried out within our laboratory using commercially sourced preparations of the small leucine-rich proteoglycans (SLRPs), decorin and biglycan, to investigate their influence on nerve cell growth. Unusual results compelled us to analyse the composition and purity of both preparations of these proteoglycans (PGs) using both mass spectrometry (MS) and Western blotting, with and without various enzymatic deglycosylations. Commercial ‘decorin’ and ‘biglycan’ were found to contain a mixture of PGs including not only both decorin and biglycan but also fibromodulin and aggrecan. The unexpected effects of ‘decorin’ and ‘biglycan’ on nerve cell growth could be explained by these impurities. Decorin and biglycan contain either chondroitin or dermatan sulfate glycosaminoglycan (GAG) chains whereas fibromodulin only contains keratan sulfate and the large (>2500 kDa), highly glycosylated aggrecan contains both keratan and chondroitin sulfate. The different structure, molecular weight and composition of these impurities significantly affected our work and any conclusions that could be made. These findings beg the question as to whether scientists need to verify the purity of each commercially obtained reagent used in their experiments. The implications of these findings are vast, since the effects of these impurities may already have led to inaccurate conclusions and reports in the literature with concomitant loss of researchers’ funds and time.

The relationship between findings on magnetic resonance imaging and previous history of low back pain

The objective of this study was to evaluate the relationship between magnetic resonance imaging (MRI) findings and previous low back pain (LBP) in participants without current LBP. Current LBP was defined as LBP during the past month. Previous LBP was defined as a history of medical consultation for LBP. Ninety-one participants without current LBP were included. Sagittal T2-weighted MRI was used to assess the intervertebral space from T12/L1 to L5/S1. These images were classified into five grades based on the Pfirrmann grading system. Furthermore, we evaluated the presence of disk bulging, high-intensity zone, and spondylolisthesis. We compared the MRI findings between groups with (27 participants) and without (64 participants) previous LBP without current LBP. Intraobserver and interobserver kappa values were evaluated. Participants had an average age of 34.9 years; 47 were female and 44 were male; and their average body mass index was 21.8 kg/m². Compared to the group of participants without previous LBP, the group of participants with previous LBP had a significantly higher incidence of disk degeneration such as a Pfirrmann grade ≥3, disk bulging, and high-intensity zone in the analyses adjusted by age and sex. There were no significant differences in spondylolisthesis between the groups. An odds ratio of >10 was only found for Pfirrmann grade ≥3, ie, a Pfirrmann grade ≥3 was strongly associated with a history of previous LBP in participants without current LBP.

Prevalence of lumbar spondylosis and its association with low back pain among community-dwelling Japanese women

Background

Lumbar spondylosis is more prevalent among the middle-aged and elderly, but few population-based studies have been conducted, especially in Japan. The purpose of this study was to explore the prevalence of lumbar spondylosis and its associations with low back pain among community-dwelling Japanese women.

Methods

Lateral radiographs of the lumbar spine were obtained from 490 Japanese women ≥ 40 years old, and scored for lumbar spondylosis using the Kellgren-Lawrence (KL) grade at lumbar intervertebral level from L1/2 to L5/S1. Height and weight were measured, and body mass index (BMI) was calculated. Low back pain in subjects was assessed using a self-administered questionnaire. Stiffness index (bone mass) was measured at the calcaneal bone using quantitative ultrasound.

Results

Prevalence of radiographic lumbar spondylosis for KL ≥ 2, KL ≥ 3 and low back pain were 76.7%, 38.8% and 20.0%, respectively. Age was positively associated with radiographic lumbar spondylosis (KL = 2, KL ≥ 3) and low back pain. Greater BMI was associated with lumbar spondylosis with KL = 2, but not with KL ≥ 3. Stiffness index was associated with neither radiographic lumbar spondylosis nor low back pain. Multiple logistic regression analysis identified radiographic lumbar spondylosis (KL ≥ 3) at L3/4, L4/5 and L5/S1 was associated with low back pain, independent of age, BMI and stiffness index.

Conclusion

Severe lumbar spondylosis at the middle or lower level may contribute to low back pain.

Self-assembling peptide hydrogel for intervertebral disc tissue engineering

Cell-based therapies for regeneration of intervertebral discs are regarded to hold promise for degenerative disc disease treatment, a condition that is strongly linked to lower back pain. A de novo self-assembling peptide hydrogel (SAPH), chosen for its biocompatibility, tailorable properties and nanofibrous architecture, was investigated as a cell carrier and scaffold for nucleus pulposus (NP) tissue engineering. Oscillatory rheology determined that the system would likely be deliverable via minimally invasive procedure and mechanical properties could be optimised to match the stiffness of the native human NP. After three-dimensional culture of NP cells (NPCs) in the SAPH, upregulation of NP-specific genes (KRT8, KRT18, FOXF1) confirmed that the system could restore the NP phenotype following de-differentiation during monolayer culture. Cell viability was high throughout culture whilst, similarly to NPCs in vivo, the viable cell population remained stable. Finally, the SAPH stimulated time-dependent increases in aggrecan and type II collagen deposition, two important NP extracellular matrix components. Results supported the hypothesis that the SAPH could be used as a cell delivery system and scaffold for the treatment of degenerative disc disease.

STATEMENT OF SIGNIFICANCE

Lower back pain (LBP) prevalence is widespread due to an aging population and the limited efficacy of current treatments. As LBP is strongly associated with intervertebral disc (IVD) degeneration, it is thought that cell-based therapies could alleviate LBP by repairing IVD tissue. Various natural and synthetic biomaterials have been investigated as potential IVD tissue engineering scaffolds. Self-assembling peptide hydrogels (SAPHs) combine advantages of both natural and synthetic biomaterials; for example they are biocompatible and have easily modifiable properties. The present study demonstrated that a de novo SAPH had comparable strength to the native tissue, was injectable, restored the IVD cell phenotype and stimulated deposition of appropriate matrix components. Results illustrated the promise of SAPHs as scaffolds for IVD tissue engineering.

Biological Treatment Approaches for Degenerative Disc Disease: A Review of Clinical Trials and Future Directions

Biologic-based treatment strategies for musculoskeletal diseases have gained traction over the past 20 years as alternatives to invasive, costly, and complicated surgical interventions. Spinal degenerative disc disease (DDD) is among the anatomic areas being investigated among this group, notably due to its high incidence and functional debilitation. In this review, we report the literature encompassing the use of biologic-based therapies for DDD. Articles published between January 1995 and November 2015 were reviewed, with a subset meeting the primary and secondary inclusion criteria of clinical trial results that could be sub-classified into bimolecular, cell-based, or gene therapies, as well as studies investigating the utility of allogeneic and tissue-engineered intervertebral discs. Ongoing clinical trials that have not yet published results are also mentioned to present the current state of the field. This exciting area has demonstrated positive and encouraging results across multiple strategies; thus, future bimolecular and regenerative techniques and understanding will likely lead to an increase in the number of human clinical trials assessing these therapies.

Diagnosing Discogenic Low Back Pain Associated with Degenerative Disc Disease Using a Medical Interview

Purposes

To evaluate the usefulness of our original five questions in a medical interview for diagnosing discogenic low back pain (LBP), and to establish a support tool for diagnosing discogenic LBP.

Materials and Methods

The degenerative disc disease (DDD) group (n = 42) comprised patients diagnosed with discogenic LBP associated with DDD, on the basis of magnetic resonance imaging findings and response to analgesic discography (discoblock). The control group (n = 30) comprised patients with LBP due to a reason other than DDD. We selected patients from those who had been diagnosed with lumbar spinal stenosis and had undergone decompression surgery without fusion. Of them, those whose postoperative LBP was significantly decreased were included in the control group. We asked patients in both groups whether they experienced LBP after sitting too long, while standing after sitting too long, squirming in a chair after sitting too long, while washing one’s face, and in the standing position with flexion. We analyzed the usefulness of our five questions for diagnosing discogenic LBP, and performed receiver operating characteristic (ROC) curve analysis to develop a diagnostic support tool.

Results

There were no significant differences in baseline characteristics, except age, between the groups. There were significant differences between the groups for all five questions. In the age-adjusted analyses, the odds ratios of LBP after sitting too long, while standing after sitting too long, squirming in a chair after sitting too long, while washing one’s face, and in standing position with flexion were 10.5, 8.5, 4.0, 10.8, and 11.8, respectively. The integer scores were 11, 9, 4, 11, and 12, respectively, and the sum of the points of the five scores ranged from 0 to 47. Results of the ROC analysis were as follows: cut-off value, 31 points; area under the curve, 0.92302; sensitivity, 100%; and specificity, 71.4%.

Conclusions

All five questions were useful for diagnosing discogenic LBP. We established the scoring system as a support tool for diagnosing discogenic LBP.

Interleukin-9 Promotes TNF-α and PGE2 Release in Human Degenerated Intervertebral Disc Tissues

STUDY DESIGN

Based on human disc surgical samples and isolated cells in vitro, we undertook a descriptive and mechanistic investigation of proinflammatory effects of interleukin (IL)-9 in intervertebral disc (IVD) degeneration.

OBJECTIVE

To investigate the proinflammatory role of IL-9 in the pathological process of IVD degeneration.

SUMMARY OF BACKGROUND DATA

IL-9 is known as a pleiotropic cytokine that regulates the human pathogenesis of inflammatory and autoimmune diseases. However, whether IL-9 cytokine is involved in the immuno-inflammatory pathogenesis of IVD degeneration is unclear.

METHODS

The IVD samples were obtained from 45 patients. Immunohistochemistry, western blot, and real-time Polymerase Chain Reaction (PCR) were performed to detect the expression of IL-9 and tumor necrosis factor alpha (TNF-α) in the degenerated IVDs. Moreover, nucleus pulposus (NP) cells were treated with 0, 1, 10, and 100 ng/mL IL-9 cytokine and stimulated with IL-9 alone at 100 ng/mL for 0, 12, 24, and 48 hours. TNF-α expression was determined by immunofluorescence staining, western blot, and real-time PCR, respectively. The amounts of TNF-α and prostaglandin E2 (PGE2) in the supernatant were quantified by enzyme-linked immunosorbent assay. Additionally, Spearman correlation analyses were performed to analyze the correlation between Pfirrmann grading score of the involved degenerated IVDs and serum levels of IL-9.

RESULTS

The expressions of IL-9 and TNF-α in degenerated IVD tissues were dramatically elevated in comparison with the control. IL-9 significantly up-regulated the TNF-α and PGE2 secretion of NP cells in dose- and time-dependent manner. Moreover, there is a positive correlation between IL-9 serum level and severity of involved IVD degeneration.

CONCLUSION

Our findings suggest that IL-9 may play a potential role in the inflammatory processes of IVD degeneration. IL-9 may be involved in the IVD degeneration, at least in part, though stimulating the release of TNF-α and PGE2 in NP cells.

LEVEL OF EVIDENCE

N/A.

Identification of subgroups of inflammatory and degenerative MRI findings in the spine and sacroiliac joints: a latent class analysis of 1037 patients with persistent low back pain

Background

The aim of this study was to investigate subgroups of magnetic resonance imaging (MRI) findings for the spine and sacroiliac joints (SIJs) using latent class analysis (LCA), and to investigate whether these subgroups differ in their demographic and clinical characteristics.

Methods

The sample included 1037 patients aged 18–40 years with persistent low back pain (LBP). LCA was applied to MRI findings of the spine and SIJs. The resulting subgroups were tested for differences in self-reported demographic and clinical characteristics.

Results

A five-class model was identified: Subgroup 1, ‘No or few findings’ (n = 116); Subgroup 2, ‘Mild spinal degeneration’ (n = 540); Subgroup 3, ‘Moderate to severe spinal degeneration’ (n = 229); Subgroup 4, ‘Moderate to severe spinal degeneration with mild SIJ findings’ (n = 68); and Subgroup 5, ‘Mild spinal degeneration with moderate to severe SIJ findings’ (n = 84). The two SIJ subgroups (Subgroups 4 and 5) had a higher median activity limitation score (Roland Morris Disability Questionnaire calculated as a proportional score: 65 (IQR 48–78)/65 (48–78)) compared with Subgroups 1–3 (48 (35–74)/57 (39–74)/57 (39–74)), a higher prevalence of women (68 % (95 % CI 56–79)/68 % (58–78)) compared with Subgroups 2 and 3 (51 % (47–55)/40 % (33–46)), a higher prevalence of being overweight (67 % (95 % CI 55–79)/53 % (41–65)) compared with Subgroup 1 (36 % (26–46)) and a higher prevalence of previous LBP episodes (yes/no: 81 % (95 % CI 71–91)/79 % (70–89)) compared with Subgroup 1 (58 % (48–67)). Subgroup 5 was younger than Subgroup 4 (median age 29 years (IQR 25–33) versus 34 years (30–37)) and had a higher prevalence of HLA-B27 (40 % (95 % CI 29–50)) compared with the other subgroups (Subgroups 1–4: 12 % (6–18)/7 % (5–10)/6 % (3–9)/12 % (4–20)). Across the subgroups with predominantly spinal findings (Subgroups 1–3), median age, prevalence of men, being overweight and previous LBP episodes were statistically significantly lower in Subgroup 1, higher in Subgroup 2 and highest in Subgroup 3.

Conclusions

Five distinct subgroups of MRI findings in the spine and SIJs were identified. The results indicate that SIJ MRI findings not only can be seen as a part of the spondyloarthritis disease entity, but also are associated with age, gender and being overweight. Furthermore, the results indicate that LBP patients with SIJ MRI findings are more disabled compared with patients without SIJ MRI findings, and that moderate to severe spinal degeneration and/or SIJ MRI findings may be associated with recurrent pain.

Electronic supplementary material

The online version of this article (doi:10.1186/s13075-016-1131-x) contains supplementary material, which is available to authorized users.

Classification of Schmorl's nodes of the lumbar spine and association with disc degeneration: a large-scale population-based MRI study

OBJECTIVE

Schmorl's nodes (SN) are highly associated with lumbar disc degeneration (DD). However, SN present with different morphologies/topographies that may be associated with varying degrees of DD. This study proposed a classification of SN to determine their morphological/topographical prevalence and association with the severity of DD.

METHODS

Sagittal T2-weighted MRIs were assessed to identify SN and additional imaging findings from L1-S1 in 2,449 individuals. SN characteristics were classified by six criteria: disc level; endplate involvement; shape; size; location of endplate zone; and the presence of marrow changes. Hierarchical clustering was performed to identify distinct SN characteristics with endplate patterns.

RESULTS

Good to excellent observer classification reliability was noted. SN most commonly presented at the L1 and L2 disc levels, and entailed one-third of the endplate, predominantly the middle zone. Round shape (39.2%) was the most common SN shape. Four specific SN and endplate linkage patterns were identified. 8.3% of identified SN (n = 960) were "Atypical SN". Multivariable regression showed that "Typical SN" and "Atypical SN", depending on levels, were associated with an adjusted 2- to 4-fold and a 5- to 13-fold higher risk of increased severity of DD, respectively (p < 0.05).

CONCLUSIONS

This is the first large-scale magnetic resonance imaging (MRI) study to propose a novel SN classification. Specific SN-types were identified, which were associated with more severe DD. This study further broadens our understanding of the role of SN and degrees of DD, further expanding on the SN phenotyping that can be internationally adopted for utility assessment.

Matrix metalloproteinase 12 is an indicator of intervertebral disc degeneration co-expressed with fibrotic markers

OBJECTIVE

Recent evidence suggests a role of fibrogenesis in intervertebral disc (IVD) degeneration. We aim to explore if fibrotic genes may serve as IVD degeneration indicators, and if their expression is associated with myofibroblast activity.

DESIGN

Transcriptional expression of fibrosis markers (COL1A1, COL3A1, FN1, HSP47, MMP12, RASAL1) were analyzed in degenerated (D) and non-degenerated (ND) human nucleus pulposus (NP) and annulus fibrosus (AF) cells, along with traditional (SOX9, ACAN) and newly established degeneration markers (CDH2, KRT19, KRT18, FBLN1, MGP, and COMP). Protein expression was investigated by immunohistochemistry in human IVDs, and in rodent IVDs undergoing natural ageing or puncture-induced degeneration. Co-expression with myofibroblast markers was examined by double staining on human and rat specimens. Disc degeneration severity and extent of fibrosis were determined by histological scoring and picrosirius red staining respectively.

RESULTS

Human D-NP showed more intensive staining for picrosirius red than ND-NP. Among the genes examined, D-NP showed significantly higher MMP12 expression along with lower KRT19 expression. Protein expression analysis revealed increased MMP12(+) cells in human D-IVD. Histological scoring indicated mild degeneration in the punctured rat discs and discs of ageing mouse. Higher MMP12 positivity was found in peripheral NP and AF of the degenerative rat discs and in NP of the aged mice. In addition, human D-NP and D-AF showed increased α-SMA(+) cells, indicating enhanced myofibroblast activity. MMP12 was found co-expressed with α-SMA, FSP1 and FAP-α in human and rat degenerative IVDs.

CONCLUSIONS

Our study suggests that in addition to a reduced KRT19 expression, an increased expression of MMP12, a profibrotic mediator, is characteristic of disc degenerative changes. Co-expression study indicates an association of the increased MMP12 positivity with myofibroblast activity in degenerated IVDs. Overall, our findings implicate an impact of MMP12 in disc cell homeostasis. The precise role of MMP12 in IVD degeneration warrants further investigation.

Automated Pressure-Controlled Discography in Patients Undergoing Anterior Lumbar Interbody Fusion for Discogenic Back Pain

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

To compare the clinical outcomes of patients undergoing anterior lumbar interbody fusion (ALIF) with or without automated pressure-controlled discography (APCD) before the procedure.

METHODS

Patients (n = 36) who underwent ALIF for lumbar discogenic back pain between 2008 and 2013 and were followed for more than 6 months were enrolled in this study. APCD was performed to identify discogenic back pain. Preoperative x-rays, computed tomography images, and magnetic resonance images were obtained. The intervertebral disc height, type of Modic change, grade of disc degeneration, and fusion rate were determined. Additionally, the presence or absence of high-intensity zone and vacuum disc were checked preoperatively. Clinical evaluation was performed by visual analog scale (0 = no pain, 10 = worst pain imaginable), Oswestry Disability Index (ODI), and 36-Item Short Form Health Survey before surgery and every 6 months postoperatively.

RESULTS

The average patient age was 53.3 years (range, 31-73 years). The mean follow-up durations were 19.7 months. Seventeen patients (the APCD-ALIF group) underwent ALIF after APCD, and 19 patients underwent ALIF without APCD. The APCD-ALIF group had significantly improved clinical outcomes compared with the control group (visual analog scale score 1.8 ± 1.6 vs. 3.3 ± 2.4; P = 0.039: ODI score 6.7 ± 6.3 vs. 12.1 ± 6.8; P = 0.019). The surgical improvement rate was significantly associated with ODI score (P = 0.005).

CONCLUSIONS

The results of this study confirm that APCD aids surgical outcomes of ALIF in patients with suspected lumbar discogenic pain. We recommend performing APCD before ALIF to confirm lumbar discogenic pain.

Classification of High Intensity Zones of the Lumbar Spine and Their Association with Other Spinal MRI Phenotypes: The Wakayama Spine Study

INTRODUCTION

High intensity zones (HIZ) of the lumbar spine are a phenotype of the intervertebral disc noted on MRI whose clinical relevance has been debated. Traditionally, T2-weighted (T2W) magnetic resonance imaging (MRI) has been utilized to identify HIZ of lumbar discs. However, controversy exists with regards to HIZ morphology, topography, and association with other MRI spinal phenotypes. Moreover, classification of HIZ has not been thoroughly defined in the past and the use of additional imaging parameters (e.g. T1W MRI) to assist in defining this phenotype has not been addressed.

MATERIALS AND METHODS

A cross-sectional study of 814 (69.8% females) subjects with mean age of 63.6 years from a homogenous Japanese population was performed. T2W and T1W sagittal 1.5T MRI was obtained on all subjects to assess HIZ from L1-S1. We created a morphological and topographical HIZ classification based on disc level, shape type (round, fissure, vertical, rim, and enlarged), location within the disc (posterior, anterior), and signal type on T1W MRI (low, high and iso intensity) in comparison to the typical high intensity on T2W MRI.

RESULTS

HIZ was noted in 38.0% of subjects. Of these, the prevalence of posterior, anterior, and both posterior/anterior HIZ in the overall lumbar spine were 47.3%, 42.4%, and 10.4%, respectively. Posterior HIZ was most common, occurring at L4/5 (32.5%) and L5/S1 (47.0%), whereas anterior HIZ was most common at L3/4 (41.8%). T1W iso-intensity type of HIZ was most prevalent (71.8%), followed by T1W high-intensity (21.4%) and T1W low-intensity (6.8%). Of all discs, round types were most prevalent (anterior: 3.6%, posterior: 3.7%) followed by vertical type (posterior: 1.6%). At all affected levels, there was a significant association between HIZ and disc degeneration, disc bulge/protrusion and Modic type II (p<0.01). Posterior HIZ and T1W high-intensity type of HIZ were significantly associated with disc bulge/protrusion and disc degeneration (p<0.01). In addition, posterior HIZ was significantly associated with Modic type II and III. T1W low-intensity type of HIZ was significantly associated with Modic type II.

CONCLUSIONS

This is the first large-scale study reporting a novel classification scheme of HIZ of the lumbar spine. This study is the first that has utilized T2W and T1W MRIs in differentiating HIZ sub-phenotypes. Specific HIZ sub-phenotypes were found to be more associated with specific MRI degenerative changes. With a more detailed description of the HIZ phenotype, this scheme can be standardized for future clinical and research initiatives.

Current and future perspectives on lumbar degenerative disc disease: a UK survey exploring specialist multidisciplinary clinical opinion

OBJECTIVES

Despite lumbar degenerative disc disease (LDDD) being significantly associated with non-specific low back pain and effective treatment remaining elusive, specialist multidisciplinary clinical stakeholder opinion remains unexplored. The present study examines the views of such experts.

DESIGN

A reliable and valid electronic survey was designed to establish trends using theoretical constructs relating to current assessment and management practices. Clinicians from the Society of Back Pain Research (SBPR) UK were invited to take part. Quantitative data were collated and coded using Bristol Online Surveys (BOS) software, and content analysis was used to systematically code and categorise qualitative data.

SETTING

Specialist multidisciplinary spinal interest group in the UK.

PARTICIPANTS

38/141 clinically active, multidisciplinary SBPR members with specialist spinal interest participated. Among them, 84% had >9 years postgraduate clinical experience.

INTERVENTIONS

None.

OUTCOME MEASURES

Frequency distributions were used to establish general trends in quantitative data. Qualitative responses were coded and categorised in relation to each theme and percentage responses were calculated.

RESULTS

LDDD symptom recurrence, in the absence of psychosocial influence, was associated with physical signs of joint stiffness (26%), weakness (17%) and joint hypermobility (6%), while physical factors (21%) and the ability to adapt (11%) were postulated as reasons why some experience pain and others do not. No one management strategy was supported exclusively or with consensus. Regarding effective modalities, there was no significant difference between allied health professional and medic responses (p=0.1-0.8). The future of LDDD care was expressed in terms of improvements in patient communication (35%), patient education (38%) and treatment stratification (24%).

CONCLUSIONS

Results suggest that multidisciplinary expert spinal clinicians appear to follow UK-based assessment guidelines with regard to recurrent LDDD; there are, however, inconsistencies in the management approaches supported. This reflects the current literature and the lack of specific, formalised guidance. LDDD treatment stratification and further research are explicitly supported.

Resistin Promotes Intervertebral Disc Degeneration by Upregulation of ADAMTS-5 Through p38 MAPK Signaling Pathway

STUDY DESIGN

Rat nucleus pulposus (NP) cells were activated with resistin with or without p38 mitogen-activated protein kinase (MAPK) pathway inhibition. The expression of a disintegrin and metalloprotease with thrombospondin motif-5 (ADAMTS-5), which plays an important role in intervertebral disc degeneration (IDD), was determined.

OBJECTIVE

The aim of this study was to demonstrate whether resistin can influence the ADAMTS-5 expression and to further investigate the underlying mechanisms.

SUMMARY OF BACKGROUND DATA

Obesity has been demonstrated to promote IDD, whereas the exact mechanism remains poorly understood. Resistin, as an important adipokine, is increased with obesity and has been shown to play pro-inflammatory and catabolic role in cartilage metabolism. However, the effect of resistin on the catabolic enzymes within NP cells remains unknown.

METHODS

We exposed NP cells to resistin, and the transcriptional activity, gene expression, and protein levels of ADAMTS-5 were measured by luciferase reporter assay, qRT-polymerase chain reaction, immunofluorescence, and western blot, respectively. The activation of p38 MAPK pathways was detected using western blot analysis.

RESULTS

Resistin had no effect on cell viability. Resistin increased ADAMTS-5 expression in rat NP cells time and dose dependently. The p38 MAPK signaling pathway was activated after exposure to resistin. Treatment with p38 inhibitor decreased the upregulation of ADAMTS-5 by resistin.

CONCLUSION

The current study, for the first time, investigated the role of resistin in ADAMTS-5 regulation in IDD. These findings provide novel evidence supporting the causative role of obesity in IDD, which is important to develop novel preventative or therapeutic treatment in disc degenerative disorders.

LEVEL OF EVIDENCE

N/A.

Association Between Lumbar Spine Sagittal Alignment and L4-L5 Disc Degeneration Among Asymptomatic Young Adults

STUDY DESIGN

Cross-sectional observational study on the relationship between the degrees of disc degeneration and sagittal alignment in asymptomatic healthy individuals.

OBJECTIVE

This study sought to determine whether the sagittal spine alignment subtype is related to the prevalence of lumbar disc degeneration.

SUMMARY AND BACKGROUND DATA

Sagittal balance and spinopelvic parameters might be risk factors for disc degeneration.

METHODS

A total of 70 asymptomatic participants (36 women and 34 men) without regular physical activity were categorized according to the four subtypes of sagittal alignment proposed by Roussouly. All participants underwent magnetic resonance imaging of the lumbar spine (1.5T) and panoramic radiography of the spine. The degree of disc degeneration was graded using T2-weighted images according to the Pfirrmann classification. Spinopelvic parameters and vertebral curvatures were measured on digital panoramic radiographs using Surgimap software. Interobserver analyses for the Pfirrmann classification and spinopelvic parameters were assessed using the weighted Kappa and intraclass correlation coefficient (ICC), respectively.

RESULTS

The Kappa associated with disc degeneration classification was 0.79 (95% confidence intervals 0.72-0.87). The ICCs were excellent, with small confidence intervals for all spinopelvic parameters. The type II group (flat lordosis) showed a higher frequency of degenerated discs at L4-L5 (P = 0.03) than the type IV group (long and curved lumbar spine). No significant differences in disc degeneration were observed among the four subtypes at the other disc levels. We found a negative, moderate correlation between the spinopelvic parameters and the occurrence of disc degeneration in the type II group.

CONCLUSION

The Roussouly subtype II sagittal alignment is significantly associated with disc degeneration at L4-L5 in asymptomatic young adults. Our results support the hypothesis that spinal sagittal alignment plays a role in early disc degeneration.

LEVEL OF EVIDENCE

3.

The role of MRI in understanding the underlying mechanisms in obesity associated diseases

Obesity and its possible association with diseases including diabetes and cardiovascular diseases have been studied for decades for its impact on healthcare. Recent studies clearly indicate the need for developing accurate and reproducible methodologies for assessing body fat content and distribution. Body fat distribution plays a significant role in developing an insight in the underlying mechanisms in which adipose tissue is linked with various diseases. Among imaging technologies including computerized axial tomography (CAT or CT), magnetic resonance imaging (MRI), and magnetic resonance spectroscopy (MRS), MRI and MRS seem to be the best emerging techniques and together are being considered as the gold standard for body fat content and distribution. This paper reviews studies up to the present time involving different methodologies of these two emerging technologies and presents the basic concepts of MRI and MRS with required novel image analysis techniques in accurate, quantitative, and direct assessment of body fat content and distribution. This article is part of a Special Issue entitled: Oxidative Stress and Mitochondrial Quality in Diabetes/Obesity and Critical Illness Spectrum of Diseases - edited by P. Hemachandra Reddy.

Two subtypes of intervertebral disc degeneration distinguished by large-scale population-based study

BACKGROUND CONTEXT

Lumbar disc degeneration (LDD) is a major cause of low back pain, and is a common and disabling condition worldwide. It has been defined and measured by multiple spine magnetic resonance imaging (MRI) features, but the heterogeneity among them has never been fully addressed.

PURPOSE

This study examined the intercorrelations, risk factor associations, and single nucleotide polymorphism (SNP) heritabilities of lumbar disc MRI features in a large-scale sample to classify the different intervertebral disc phenotypes associated with LDD.

STUDY DESIGN

A cross-sectional study was conducted consisting of 2,943 volunteers of Southern Chinese origin (mean age: 41.1 years; range: 15-55 years; 59.6% women).

OUTCOME MEASURES

The outcome measures were MRI phenotypic spinal patterns and their risk factor profiles in relation to developmental or degenerative origins of disc degeneration.

METHODS

Sagittal T2-weighted MRI of the lumbar spine from L1 to S1 was assessed. The MRI features of lumbar intervertebral disc changes, such as disc signal intensity loss and disc bulges or extrusions, as well as additional imaging phenotypes of end plate changes, high-intensity zones, and bone marrow changes, were evaluated. Blood samples were taken for genotyping using the HumanOmni-ZhongHua-8 BeadChip. Subject demographics, environmental, and lifestyle factors were assessed by questionnaires. Multivariate statistical techniques were used for phenotype evaluation. Polychoric correlations and local regression statistical analyses were performed. The genetic components contributed by common SNPs were estimated by comparing genetic correlations and phenotypic correlations using the Genome-Wide Complex Trait Analysis (GCTA) tool.

RESULTS

The study noted that lumbar disc MRI features separated into two groups with differential patterns of risk factor associations. A subset of lumbar disc abnormalities, including end plate changes but also upper lumbar disc bulging and signal intensity loss, may have a developmental origin. Subsequent degenerative changes, typically affecting the lower lumbar discs, then emerge as individuals age and are associated with body mass index.

CONCLUSIONS

This is the first large-scale study to identify two distinct patterns of lumbar disc alterations, noting degenerative changes and a possible developmental component affecting the lumbar spine. This new classification provides a starting point for a more homogeneous phenotype definition, which may provide greater statistical power and precision in future genetic and epidemiologic studies. In addition, such insights may have direct clinical implications in the prevention, therapeutics, and prognostics of patients with disc degeneration.

Evaluation and comparison of 3D intervertebral disc localization and segmentation methods for 3D T2 MR data: A grand challenge

The evaluation of changes in Intervertebral Discs (IVDs) with 3D Magnetic Resonance (MR) Imaging (MRI) can be of interest for many clinical applications. This paper presents the evaluation of both IVD localization and IVD segmentation methods submitted to the Automatic 3D MRI IVD Localization and Segmentation challenge, held at the 2015 International Conference on Medical Image Computing and Computer Assisted Intervention (MICCAI2015) with an on-site competition. With the construction of a manually annotated reference data set composed of 25 3D T2-weighted MR images acquired from two different studies and the establishment of a standard validation framework, quantitative evaluation was performed to compare the results of methods submitted to the challenge. Experimental results show that overall the best localization method achieves a mean localization distance of 0.8 mm and the best segmentation method achieves a mean Dice of 91.8%, a mean average absolute distance of 1.1 mm and a mean Hausdorff distance of 4.3 mm, respectively. The strengths and drawbacks of each method are discussed, which provides insights into the performance of different IVD localization and segmentation methods.

Biological Treatment Approaches for Degenerative Disk Disease: A Literature Review of In Vivo Animal and Clinical Data

STUDY DESIGN

Literature review.

OBJECTIVE

Degenerative disk disease (DDD) has a negative impact on quality of life and is a major cause of morbidity worldwide. There has been a growing interest in the biological repair of DDD by both researchers and clinicians alike. To generate an overview of the recent progress in reparative strategies for the treatment of DDD highlighting their promises and limitations, a comprehensive review of the current literature was performed elucidating data from in vivo animal and clinical studies.

METHODS

Articles and abstracts available in electronic databases of PubMed, Web of Science, and Google Scholar as of December 2014 were reviewed. Additionally, data from unpublished, ongoing clinical trials was retrieved from clinicaltrials.gov and available abstracts from research forums. Data was extracted from the most recent in vivo animal or clinical studies involving any of the following: (1) treatment with biomolecules, cells, or tissue-engineered constructs and (2) annulus fibrosus repair.

RESULTS

Seventy-five articles met the inclusion criteria for review. Among these, 17 studies involved humans; 37, small quadrupeds; and 21, large quadrupeds. Findings from all treatments employed demonstrated improvement either in regenerative capacity or in pain attenuation, with the exception of one clinical study.

CONCLUSION

Published clinical studies on cell therapy have reported encouraging results in the treatment of DDD and resultant back pain. We expect new data to emerge in the near future as treatments for DDD continue to evolve in parallel to our greater understanding of disk health and pathology.

Quantitative proteomic analysis of normal and degenerated human intervertebral disc

BACKGROUND CONTEXT

Degenerative disc disease (DDD) is the most common disease of aging in humans. DDD is characterized by the gradual damage of the intervertebral discs. The disease is characterized by progressive dehydration of nucleus pulposus and disruption of annulus fibrosus of intervertebral disc.

PURPOSE

Even though it is highly prevalent, there is no effective therapy to regenerate the degenerated disc, or decrease or halt the disease progression. Therefore, novel monitoring and diagnostic tests are essential to develop an alternative therapeutic strategies which can prevent further progression of disc degeneration.

STUDY DESIGN

The study was designed to understand the proteome map of annulus fibrosus and nucleus pulposus tissues of intervertebral disc and its differential expression in patients with DDD.

METHODS

The proteome map of the annulus fibrosus and nucleus pulposus tissues of intervertebral disc was cataloged involving one-dimensional gel electrophoresis-Fourier transform mass spectrometry/ion trap tandem mass spectrometry (FTMS/ITMSMS) analysis. The altered proteome patterns of annulus fibrosus and nucleus pulposus tissues for DDD were identified using Isobaric tag for relative and absolute quantification (iTRAQ)-based quantitative proteomics coupled with FTMS/ITMSMS and network pathway analysis.

RESULTS

The study identified a total of 759 and 692 proteins from the annulus fibrosus and the nucleus pulposus tissues of the disc based on FTMS/ITMSMS analysis, which includes 118 proteins commonly identified between the two tissues. Vibrant changes were observed between the normal and the degenerating annulus fibrosus and nucleus pulposus tissues. A total of 73 and 54 proteins were identified as differentially regulated in the annulus and the nucleus tissues, respectively, between the normal and the degenerated tissues independently. Network pathway analysis mapped the differentially expressed proteins to cell adhesion, cell migration, and interleukin13 signaling pathways.

CONCLUSIONS

Altogether, the current study provides a novel vision in the biomechanism of human disc degeneration and a certain number of proteins with the potential biomarker value for the preliminary diagnosis and scenario of DDD.

The Involvement of Protease Nexin-1 (PN1) in the Pathogenesis of Intervertebral Disc (IVD) Degeneration

Protease nexin-1 (PN-1) is a serine protease inhibitor belonging to the serpin superfamily. This study was undertaken to investigate the regulatory role of PN-1 in the pathogenesis of intervertebral disk (IVD) degeneration. Expression of PN-1 was detected in human IVD tissue of varying grades. Expression of both PN-1 mRNA and protein was significantly decreased in degenerated IVD, and the expression levels of PN-1 were correlated with the grade of disc degeneration. Moreover, a decrease in PN-1 expression in primary NP cells was confirmed. On induction by IL-1β, the expression of PN-1 in NP cells was decreased at day 7, 14, and 21, as shown by western blot analysis and immunofluorescence staining. PN-1 administration decreased IL-1β-induced MMPs and ADAMTS production and the loss of Agg and Col II in NP cell cultures through the ERK1/2/NF-kB signaling pathway. The changes in PN-1 expression are involved in the pathogenesis of IVD degeneration. Our findings indicate that PN-1 administration could antagonize IL-1β-induced MMPs and ADAMTS, potentially preventing degeneration of IVD tissue. This study also revealed new insights into the regulation of PN-1 expression via the ERK1/2/NF-kB signaling pathway and the role of PN-1 in the pathogenesis of IVD degeneration.

Spine Kinematics During Prone Extension in People With and Without Low Back Pain and Among Classification-Specific Low Back Pain Subgroups

Study Design Cross-sectional observational design. Background Spine extension is used in physical therapy during examination and treatment for low back pain (LBP). However, kinematics during prone extension have not been examined using 3-D motion capture. Objectives The primary purpose was to determine differences in spine kinematics during prone extension between subjects with and without LBP. An exploratory analysis was conducted to examine kinematic differences among LBP subgroups. Methods Kinematics of the thoracic and lumbar spine were examined during prone extension, using optical motion capture, in 18 subjects with LBP and 17 subjects without LBP (control group). Excursion of each spinal region was calculated for the entire movement and during 25% increments of extension movement duration. Subjects with LBP were examined and assigned to subgroups using 3 different classification systems for LBP. Repeated-measures analysis-of-variance tests were used to examine effects of group (LBP, control), spine region, and increment of movement duration, and to explore effects of LBP subgroup. Results For spine kinematics, there was a significant group-by-region interaction effect (P<.05). Subjects with LBP displayed less lower lumbar extension (13.3° ± 4.9°) than control subjects (21.4° ± 9.2°). The majority of lower lumbar extension occurred during the first 50% of the motion for subjects with LBP. Subgroup-by-region interaction effects were significant for 2 of 3 LBP classification systems (P<.05). Conclusion Subjects with LBP displayed less lower lumbar extension than control subjects during prone extension. These differences should be considered when evaluating and prescribing prone extension. The interpretation of subgroup differences with prone extension kinematics is limited in the current study by the small sample size, but may need to be considered in future studies of spine kinematics. Level of Evidence Diagnosis, level 4. J Orthop Sports Phys Ther 2016;46(7):571-579. Epub 12 May 2016. doi:10.2519/jospt.2016.6159.

Axial loading during MRI influences T2-mapping values of lumbar discs: a feasibility study on patients with low back pain

PURPOSE

To investigate whether axial loading of the spine during MRI (alMRI) instantaneously induces changes in biochemical disc features as reflected by altered quantitative T2 values in patients with chronic low back pain (LBP).

METHODS

T2 mapping was performed on 11 LBP patients (54 lumbar discs) during the conventional unloaded MRI and subsequent alMRI. Each disc was divided into five volumetric regions of interests (ROIs), anterior annulus fibrosus (AF) (ROI 1), the interface anterior AF-nucleus pulposus (NP) (ROI 2), NP (ROI 3), the interface NP-posterior AF (ROI 4), and the posterior AF (ROI 5). The mean T2 values for each ROI were compared between MRI and alMRI and correlated with degeneration grade (Pfirrmann), disc angle, and disc level.

RESULTS

With alMRI, T2 values increased significantly in the whole disc as well as in various parts of the disc with an increase in ROI 1-3 and a decrease in ROI 5. The changes in T2 values correlated to degeneration grade, changes in disc angle, and lumbar level.

CONCLUSION

alMRI instantaneously induces T2-value changes in lumbar discs and is, thus, a feasible method to reveal dynamic, biochemical disc features in patients with chronic LBP.

N-cadherin is Key to Expression of the Nucleus Pulposus Cell Phenotype under Selective Substrate Culture Conditions

Nucleus pulposus (NP) cells of the intervertebral disc are essential for synthesizing extracellular matrix that contributes to disc health and mechanical function. NP cells have a unique morphology and molecular expression pattern derived from their notochordal origin, and reside in N-cadherin (CDH2) positive cell clusters in vivo. With disc degeneration, NP cells undergo morphologic and phenotypic changes including loss of CDH2 expression and ability to form cell clusters. Here, we investigate the role of CDH2 positive cell clusters in preserving healthy, biosynthetically active NP cells. Using a laminin-functionalized hydrogel system designed to mimic features of the native NP microenvironment, we demonstrate NP cell phenotype and morphology is preserved only when NP cells form CDH2 positive cell clusters. Knockdown (CRISPRi) or blocking CDH2 expression in vitro and in vivo results in loss of a healthy NP cell. Findings also reveal that degenerate human NP cells that are CDH2 negative can be promoted to re-express CDH2 and healthy, juvenile NP matrix synthesis patterns by promoting cell clustering for controlled microenvironment conditions. This work also identifies CDH2 interactions with β-catenin-regulated signaling as one mechanism by which CDH2-mediated cell interactions can control NP cell phenotype and biosynthesis towards maintenance of healthy intervertebral disc tissues.

Does elite swimming accelerate lumbar intervertebral disc degeneration and increase low back pain? A cross-sectional comparison

PURPOSE

The aim was to elucidate elite swimming's possible influence on lumbar disc degeneration (DD) and low back pain (LBP).

METHODS

Lumbar spine MRI was performed on a group of elite swimmers and compared to a matched Finnish population-based no-sport group.

RESULTS

One hundred elite swimmers and 96 no-sport adults, mean age 18.7/20.8, respectively, participated. Overall, the two groups had similar prevalence of DD. Swimmers had more DD in the upper lumbar spine but tended to have less DD at the lowest level. Prevalence of bulges and disc herniations were similar, but swimmers had significantly more bulges at L4-5. The swimmers reported less LBP, although not significantly (N.S.). If degenerative findings were present, the association between them and LBP was stronger in the no-sport group.

CONCLUSION

Elite swimmers and controls had similar prevalence of DD and LBP, although the pattern of DD differed between the groups. In case of DD, swimmers reported less LBP, although N.S.

MyD88-dependent Toll-like receptor 4 signal pathway in intervertebral disc degeneration

Lower back pain (LBP) is a common and remitting problem. One of the primary causes of LBP is thought to be degeneration of the intervertebral disc (IVD). The aim of the present study was to investigate the role of the myeloid differentiation primary-response protein 88 (MyD88)-dependent Toll-like receptor 4 (TLR4) signal pathway in the mechanism of IVD degeneration. IVD nucleus pulposus cells isolated and cultured from the lumbar vertebrae of Wistar rats were stimulated by various doses of lipopolysaccharide (LPS; 0.1, 1, 10 and 100 µg/ml) to simulate IVD degeneration. Cells were rinsed and cultured in serum-free Dulbecco's modified Eagle's medium/F12. Reverse transcription-quantitative polymerase chain reaction was used to determine the levels of TLR4, MyD88, tumor necrosis factor α (TNFα), and interleukin-1β (IL-1β) mRNA expression after 1, 3, 6, 9 and 12 h of incubation. Additionally, western blot and enzyme-linked immunosorbent assay analyses were used to determine the levels of TLR4, MyD88, TNFα, and IL-1β protein expression after 24, 48 and 72 h of incubation. The levels of TLR4, MyD88, TNFα and IL-1β mRNA all increased in the cells stimulated by 10 µg/ml LPS at 3, 6 and 9 h (all P<0.001). Furthermore, the levels of TLR4, MyD88, TNFα and IL-1β protein all increased at 24, 48 and 72 h (all P<0.001). Additionally, the mRNA and protein levels of TLR4, MyD88, TNFα and IL-1β increased significantly in the cells stimulated by 1, 10 and 100 µg/ml LPS compared with the control group, and reached a peak in the 10 µg/ml LPS group (all P<0.001). These results suggest that the MyD88-dependent TLR4 signal pathway is a target pathway in IVD degeneration. This pathway is time phase- and dose-dependent, and when activated can lead to the release of inflammatory factors that participate in IVD degeneration.

Magnetic Resonance Imaging in Patients With Mechanical Low Back Pain Using a Novel Rapid-Acquisition Three-Dimensional SPACE Sequence at 1.5-T: A Pilot Study Comparing Lumbar Stenosis Assessment With Routine Two-Dimensional Magnetic Resonance Sequences

PURPOSE

To minimize the burden of overutilisation of lumbar spine magnetic resonance imaging (MRI) on a resource-constrained public healthcare system, it may be helpful to image some patients with mechanical low-back pain (LBP) using a simplified rapid MRI screening protocol at 1.5-T. A rapid-acquisition 3-dimensional (3D) SPACE (Sampling Perfection with Application-optimized Contrasts using different flip angle Evolution) sequence can demonstrate common etiologies of LBP. We compared lumbar spinal canal stenosis (LSCS) and neural foraminal stenosis (LNFS) assessment on 3D SPACE against conventional 2-dimensional (2D) MRI.

METHODS

We prospectively performed 3D SPACE and 2D spin-echo MRI sequences (axial or sagittal T1-weighted or T2-weighted) at 1.5-T in 20 patients. Two blinded readers assessed levels L3-4, L4-5 and L5-S1 using: 1) morphologic grading systems, 2) global impression on the presence or absence of clinically significant stenosis (n = 60 disc levels for LSCS, n = 120 foramina for LNFS). Reliability statistics were calculated.

RESULTS

Acquisition time was ∼5 minutes for SPACE and ∼20 minutes for 2D MRI sequences. Interobserver agreement of LSCS was substantial to near perfect on both sequences (morphologic grading: kappa [k] = 0.71 SPACE, k = 0.69 T2-weighted; global impression: k = 0.85 SPACE, k = 0.78 T2-weighted). LNFS assessment had superior interobserver reliability using SPACE than T1-weighted (k = 0.54 vs 0.37). Intersequence agreement of findings between SPACE and 2D MRI was substantial to near perfect by global impression (LSCS: k = 0.78 Reader 1, k = 0.85 Reader 2; LNFS: k = 0.63 Reader 1, k = 0.66 Reader 2).

CONCLUSIONS

3D SPACE was acquired in one-quarter the time as the conventional 2D MRI protocol, had excellent agreement with 2D MRI for stenosis assessment, and had interobserver reliability superior to 2D MRI. These results justify future work to explore the role of 3D SPACE in a rapid MRI screening protocol at 1.5-T for mechanical LBP.

Disc cell senescence in intervertebral disc degeneration: Causes and molecular pathways

The accumulation of senescent disc cells in degenerative intervertebral disc (IVD) suggests the detrimental roles of cell senescence in the pathogenesis of intervertebral disc degeneration (IDD). Disc cell senescence decreased the number of functional cells in IVD. Moreover, the senescent disc cells were supposed to accelerate the process of IDD via their aberrant paracrine effects by which senescent cells cause the senescence of neighboring cells and enhance the matrix catabolism and inflammation in IVD. Thus, anti-senescence has been proposed as a novel therapeutic target for IDD. However, the development of anti-senescence therapy is based on our understanding of the molecular mechanism of disc cell senescence. In this review, we focused on the molecular mechanism of disc cell senescence, including the causes and various molecular pathways. We found that, during the process of IDD, age-related damages together with degenerative external stimuli activated both p53-p21-Rb and p16-Rb pathways to induce disc cell senescence. Meanwhile, disc cell senescence was regulated by multiple signaling pathways, suggesting the complex regulating network of disc cell senescence. To understand the mechanism of disc cell senescence better contributes to developing the anti-senescence-based therapies for IDD.

Refined Phenotyping of Modic Changes: Imaging Biomarkers of Prolonged Severe Low Back Pain and Disability

Low back pain (LBP) is the world's most disabling condition. Modic changes (MC) are vertebral bone marrow changes adjacent to the endplates as noted on magnetic resonance imaging. The associations of specific MC types and patterns with prolonged, severe LBP and disability remain speculative. This study assessed the relationship of prolonged, severe LBP and back-related disability, with the presence and morphology of lumbar MC in a large cross-sectional population-based study of Southern Chinese.We addressed the topographical and morphological dimensions of MC along with other magnetic resonance imaging phenotypes (eg, disc degeneration and displacement) on the basis of axial T1 and sagittal T2-weighted imaging of L1-S1. Prolonged severe LBP was defined as LBP lasting ≥30 days during the past year, and a visual analog scale severest pain intensity of at least 6/10. An Oswestry Disability Index score of 15% was regarded as significant disability. We also assessed subject demographics, occupation, and lifestyle factors.In total, 1142 subjects (63% females, mean age 53 years) were assessed. Of these, 282 (24.7%) had MC (7.1% type I, 17.6% type II). MC subjects were older (P = 0.003), had more frequent disc displacements (P < 0.001) and greater degree of disc degeneration (P < 0.001) than non-MC subjects. In adjusted models, any MC (odds ratio [OR] 1.48, 95% confidence interval [CI] 1.01-2.18), MC affecting whole anterior-posterior length (OR 1.62, 95% CI 1.04-2.51), and MC affecting 2/3 posterior length (OR 2.79, 95% CI 1.17-6.65) were associated with prolonged severe LBP. Type I MC tended to associate with pain more strongly than type II MC (OR 1.80, 95% CI 0.94-3.44 vs OR 1.36, 95% CI 0.88-2.09, respectively). Any MC (OR 1.47, 95% CI 1.04-2.10), type II MC (OR 1.56, 95% CI 1.06-2.31), MC affecting 2/3 posterior length (OR 2.96, 95% CI 1.27-6.89), and extensive MC (OR 1.95, 95% CI 1.21-3.15) were associated with disability. The strength of the associations increased with the number of MC.This large-scale study is the first to definitively note MC types and specific morphologies to be independently associated with prolonged severe LBP and back-related disability. This proposed refined MC phenotype may have direct implications in clinical decision-making as to the development and management of LBP. Understanding of these imaging biomarkers can lead to new preventative and personalized therapeutics related to LBP.

Association between ADAMTS-4 gene polymorphism and lumbar disc degeneration in Chinese Han population

Low back pain (LBP) is a common health problem and many LBP are caused by lumbar disc degeneration (LDD). ADAMTS-4 (a disintegrin and metalloprotease with thrombospondin motifs-4), also known as aggrecanse-1, plays a core role in degeneration of extracellular matrix in LDD. To investigate the association between ADAMTS-4 genetic polymorphism and LDD, we genotyped SNPs in and around ADAMTS-4. We recruited 482 sporadic cases of LDD and 496 healthy controls from Chinese Han population. Five SNPs were selected and phenotyped by the Sequenom MassARRAY system. Allelic, genotypic, and haplotypic association was performed. Rs4233367 (c.1877 C>T), which located in exon of ADAMTS-4 showed significant association with LDD. The T allele conferred a lower risk of LDD with an OR of 0.69 and TT genotype is at nearly one-fifth of the risk compared to CC genotype. Other tested SNPs didn't show significant difference between the case and control groups. The SNP rs4233367 in the exon of ADAMTS-4 gene may be associated with lumbar disc degeneration. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:860-864, 2016.

Expression and functional roles of estrogen receptor GPR30 in human intervertebral disc

Estrogen withdrawal, a characteristic of female aging, is associated with age-related intervertebral disc (IVD) degeneration. The function of estrogen is mediated by two classic nuclear receptors, estrogen receptor (ER)-α and -β, and a membrane bound G-protein-coupled receptor 30 (GPR30). To date, the expression and function of GPR30 in human spine is poorly understood. This study aimed to evaluate GPR30 expression in IVD, and its role in estrogen-related regulation of proliferation and apoptosis of disc nucleus pulposus (NP) cells. GPR30 expression was examined in 30 human adult NP and 9 fetal IVD. Results showed that GPR30 was expressed in NP cells at both mRNA and protein levels. In human fetal IVD, GPR30 protein was expressed in the NP at 12-14 weeks gestation, but was undetectable at 8-11 weeks. The effect of 17β-estradiol (E2) on GPR30-mediated proliferation and interleukin-1β (IL-1β)-induced apoptosis of NP cells was investigated. Cultured NP cells were treated with or without E2, GPR30 antagonist G36, and ER antagonist ICI 182,780. NP cell viability was tested by MTS assay. Apoptosis was determined by flow cytometry using fluorescence labeled annexin-V, TUNEL assay and immumnocytochemical staining of activated caspase-3. E2 enhanced cell proliferation and prevented IL-1β-induced cell death, but the effect was partially blocked by G36 and completely abrogated by a combination of ICI 182,780 and G36. This study demonstrates that GPR30 is expressed in human IVD to transmit signals triggering E2-induced NP cell proliferation and protecting against IL-1β-induced apoptosis. The effects of E2 on NP cells require both GPR30 and classic estrogen receptors.

[Lumbar spinal stenosis. From diagnosis to correct therapy]

The number of patients with a diagnosis of lumbar spinal stenosis (LSS) is steadily increasing and the expectations of patients are high; however, valid data for an appropriate therapy are lacking. Treatment is mostly the result of the surgeon's experience and the clinical focus. The findings in magnetic resonance imaging (MRI) often do not correlate with the patient's symptoms. It is proposed that treatment should start with a conservative multimodal approach. Increased pain with neurogenic claudication symptoms under conservative treatment should be treated surgically. Absolute indications for surgery, such as a conus cauda syndrome are rare. The goal of all surgical procedures is to decompress the spinal canal without compromising the stability of the motion segment. This can also make an additional fusion necessary.

Fibrotic-like changes in degenerate human intervertebral discs revealed by quantitative proteomic analysis

OBJECTIVE

Intervertebral disc degeneration (IDD) can lead to symptomatic conditions including sciatica and back pain. The purpose of this study is to understand the extracellular matrix (ECM) changes in disc biology through comparative proteomic analysis of degenerated and non-degenerated human intervertebral disc (IVD) tissues of different ages.

DESIGN

Seven non-degenerated (11-46 years of age) and seven degenerated (16-53 years of age) annulus fibrosus (AF) and nucleus pulposus (NP) samples were used. Proteins were extracted using guanidine hydrochloride, separated from large proteoglycans (PGs) by caesium chloride (CsCl) density gradient ultracentrifugation, and identified using liquid chromatography (LC) coupled with tandem mass spectrometry (MS/MS). For quantitative comparison, proteins were labeled with iTRAQ reagents. Collagen fibrils in the NP were assessed using scanning electron microscopy (SEM).

RESULTS

In the AF, quantitative analysis revealed increased levels of HTRA1, COMP and CILP in degeneration when compared with samples from older individuals. Fibronectin showed increment with age and degeneration. In the NP, more CILP and CILP2 were present in degenerated samples of younger individuals. Reduced protein solubility was observed in degenerated and older non-degenerated samples correlated with an accumulation of type I collagen in the insoluble fibers. Characterization of collagen fibrils in the NP revealed smaller mean fibril diameters and decreased porosity in the degenerated samples.

CONCLUSIONS

Our study identified distinct matrix changes associated with aging and degeneration in the intervertebral discs (IVDs). The nature of the ECM changes, together with observed decreased in solubility and changes in fibril diameter is consistent with a fibrotic-like environment.

Prospective study using anterior approach did not show association between Modic 1 changes and low grade infection in lumbar spine

INTRODUCTION

The modern literature is producing a rapidly growing number of articles which highlight the relationship between infection and lumbar disc degeneration. However, the means by which samples are collected is questionable. Posterior approach surgery is not free from skin contamination. The possibility of intraoperative contamination of disc biopsies cannot be excluded.

OBJECTIVE

The objective of this study was to determine if an association existed between lumbar disc degeneration and chronic infection of the intervertebral disc.

MATERIALS AND METHODS

313 patients (186/127, F/M) with chronic low back pain secondary to degenerative disc disease which was resistant to medical treatment were included in a single-centre prospective study. All underwent a lumbar anterior video-assisted minimally invasive fusion or disc prosthesis in L4-L5 and/or L5-S1 via an anterior retroperitoneal approach. The patients MRI scans demonstrated in Pfirrmann's classification grade IV or V disc degeneration; 385 disc drives were taken. In terms of Modic changes, 303 Modic 1, 58 Modic II and 24 absence of Modic change, respectively. All underwent intraoperative biopsy, performed according to a strict aseptic protocol. The biopsies were then cultured for 4 weeks with specialised enrichment cultures and subjected to histopathological analysis.

RESULTS

The mean age was 47 ± 8.6 years sterile cultures were obtained in 379 samples (98.4%) and 6 were positive (1.6%). The cultured bacteria were: Propionibacterium acnes (n:2), Staphylococcus epidermidis (n:2), Citrobacter freundii (n:1), and Saccharopolyspora hirsuta (n:1). Histopathological analysis did not demonstrate any evidence of a neutrophilia. There were no delayed or secondary infections.

DISCUSSION AND CONCLUSION

Unlike the posterior approach where contamination is common, the anterior video-assisted approach allows a biopsy without skin contact. This approach to the spine is the most effective way to eliminate the risk of contamination. Our results confirm the absence of any relationship between infection and disc degeneration. We suggest that the 6 positive samples in our study may be related to contamination. The absence of infection at 1-year followup is an additional argument in favour of our results. In conclusion, our study shows no association between infection and disc degeneration. The pathophysiology of disc degeneration is complex, but the current literature opens new perspectives.

Degenerative Pathways of Lumbar Motion Segments--A Comparison in Two Samples of Patients with Persistent Low Back Pain

Background

Magnetic resonance imaging (MRI) is used to identify spinal pathoanatomy in people with persistent low back pain. However, the clinical relevance of spinal degenerative MRI findings remains uncertain. Although multiple MRI findings are almost always present at the same time, research into the association with clinical outcomes (such as pain) has predominantly focused on individual MRI findings. This study aimed to: (i) investigate how multiple MRI lumbar spine findings cluster together within two different samples of patients with low back pain, (ii) classify these clusters into hypothetical pathways of degeneration based on scientific knowledge of disco-vertebral degeneration, and (iii) compare these clusters and degenerative pathways between samples.

Methods

We performed a secondary cross-sectional analysis on two dissimilar MRI samples collected in a hospital department: (1) data from the spinal MRI reports of 4,162 low back pain patients and (2) data from an MRI research protocol of 631 low back pain patients. Latent Class Analysis was used in both samples to cluster MRI findings from lumbar motion segments. Using content analysis, each cluster was then categorised into hypothetical pathways of degeneration.

Results

Six clusters of MRI findings were identified in each of the two samples. The content of the clusters in the two samples displayed some differences but had the same overall pattern of MRI findings. Although the hypothetical degenerative pathways identified in the two samples were not identical, the overall pattern of increasing degeneration within the pathways was the same.

Conclusions

It was expected that different clusters could emerge from different samples, however, when organised into hypothetical pathways of degeneration, the overall pattern of increasing degeneration was similar and biologically plausible. This evidence of reproducibility suggests that Latent Class Analysis may provide a new approach to investigating the relationship between MRI findings and clinically important characteristics such as pain and activity limitation.

Nucleus pulposus phenotypic markers to determine stem cell differentiation: fact or fiction?

Progress in mesenchymal stem cell (MSC) based therapies for nucleus pulposus (NP) regeneration are hampered by a lack of understanding and consensus of the normal NP cell phenotype. Despite the recent consensus paper on NP markers, there is still a need to further validate proposed markers. This study aimed to determine whether an NP phenotypic profile could be identified within a large population of mature NP samples.qRT-PCR was conducted to assess mRNA expression of 13 genes within human non-degenerate articular chondrocytes (AC) (n=10) and NP cells extracted from patients across a spectrum of histological degeneration grades (n=71). qRT-PCR results were used to select NP marker candidates for protein expression analysis.Differential expression at mRNA between AC and non-degenerate NP cells was only observed for Paired Box Protein 1 (PAX1) and Forkhead box F1 (FOXF1). In contrast no other previously suggested markers displayed differential expression between non-degenerate NP and AC at mRNA level. PAX1 and FOXF1 protein expression was significantly higher in the NP compared to annulus fibrosus (AF), cartilaginous endplate (CEP) and AC. In contrast Laminin-5 (LAM-332), Keratin-19 (KRT-19) and Hypoxia Inducible Factor 1 alpha (HIF1α) showed no differential expression in NP cells compared with AC cells.A marker which exclusively differentiates NP cells from AF and AC cells remains to be identified, raising the question: is the NP a heterogeneous population of cells? Or does the natural biological variation during IVD development, degeneration state and even the life cycle of cells make finding one definitive marker impossible?

Serum levels of the proinflammatory cytokine interleukin-6 vary based on diagnoses in individuals with lumbar intervertebral disc diseases

BACKGROUND

Many intervertebral disc diseases cause low back pain (LBP). Proinflammatory cytokines and matrix metalloproteinases (MMPs) participate in disc pathology. In this study, we examined levels of serum cytokines and MMPs in human subjects with diagnoses of disc herniation (DH), spinal stenosis (SS), or degenerative disc disease (DDD) relative to levels in control subjects. Comparison between subjects with DH and those with other diagnoses (Other Dx, grouped from SS and DDD) was performed to elaborate a pathological mechanism based on circulating cytokine levels.

METHODS

Study participants were recruited from a spine neurosurgery practice (n = 80), a back pain management practice (n = 27), or a control cohort (n = 26). Serum samples were collected before treatment and were assayed by multiplex assays for levels of interleukin (IL)-1β, IL-2, IL-4, IL-6, IL-8, IL-10, IL-12p70, IL-13, interferon-γ, tumor necrosis factor-α, MMP-1, MMP-3, and MMP-9. Inflammatory and degradative mediator levels were compared for subjects with LBP and control subjects, by diagnosis and by treatment groups, controlling for effects of sex, age, and reported history of osteoarthritis. Spearman's correlation coefficient was used to examine relationships with age, body mass index (BMI), symptom duration, and smoking history.

RESULTS

Serum levels of IL-6 were significantly higher in subjects with LBP compared with control subjects. Participants with LBP due to Other Dx had significantly higher levels of IL-6 than DH and controls. Serum levels of MMP-1 were significantly lower in LBP subjects, specifically those with DH, than in control subjects. Positive correlations were found between IL-6 levels and BMI, symptom duration, and age. MMP-1 levels were positively correlated with age.

CONCLUSIONS

The findings of the present clinical study are the results of the first examination of circulating cytokine levels in DDD and SS and provide evidence for a more extensive role of IL-6 in disc diseases, where patients with DDD or SS have higher serum cytokine levels than those with DH or control subjects. These findings suggest that LBP subjects have low-grade systemic inflammation, and biochemical profiling of circulating cytokines may assist in refining personalized diagnoses of disc diseases.

Modic changes of the lumbar spine: prevalence, risk factors, and association with disc degeneration and low back pain in a large-scale population-based cohort

BACKGROUND CONTEXT

Modic changes (MC) are bone marrow lesions on magnetic resonance imaging (MRI), suggestive of being associated with low back pain (LBP). Data on determinants of MC and their association with disc degeneration and other spinal phenotypes, as well as that of LBP, rely mostly on small-scale patient populations and remain controversial.

PURPOSE

This study addressed the potential determinants of MC and their association with disc degeneration and LBP among Southern Chinese.

STUDY DESIGN/SETTING

A cross-sectional, population-based study was carried out.

PATIENT SAMPLE

This study consisted of 2,449 Southern Chinese volunteers.

METHODS

Sagittal T2-weighted MRIs of the lumbar spine were assessed for the presence of MC and other spinal phenotypes (eg, disc degeneration, disc displacement, Schmorl nodes) in all individuals. Subjects' demographics, occupation, lifestyle, and clinical profiles were assessed.

RESULTS

The overall prevalence of MC was 5.8% (n=141), which increased with advancing age. Modic changes predominantly occurred at the lowest two lumbar levels (83%). In the multivariate analyses, only the presence of disc displacement and a higher disc degeneration score were associated with MC at the upper lumbar levels (L1/L2-L3/L4) (p<.01). The presence of MC at the lowest two lumbar levels (L4/L5-L5/S1) were associated with age, the presence of Schmorl nodes, disc degeneration or displacement, and historical lumbar injury (p<.01). Subjects who were both smokers and overweight or obese had increased likelihood of MC in the lower spine (OR: 2.18; 95% CI: 1.10-4.30). The presence of MC at the lower lumbar levels were associated with historical LBP (OR: 1.93; 95% CI: 1.05-3.54) and with severity and duration of symptoms (p<.05).

CONCLUSIONS

Based on one of the largest MRI studies to assess lumbar MC, we noted that MC were associated with both disc degeneration and the presence and severity of LBP. Determinants and association of MC with disc degeneration and clinical symptoms in the upper versus the lower lumbar spine were different. Our study further stresses the significance of MC as important imaging phenotypes associated with LBP.

New Predictive Index for Lumbar Paraspinal Muscle Degeneration Associated With Aging

STUDY DESIGN

A cross-sectional imaging study of paraspinal muscle degeneration using a new index for easy evaluation.

OBJECTIVE

To examine the natural progression of age-related changes in the lumbar paraspinal muscles and to verify the validity of our new index for evaluating paraspinal muscle degenerationSUMMARY OF BACKGROUND DATA.: Measurement of paraspinal muscle morphology is an effective method for reflecting atrophy and fat infiltration, but it is complicated to perform. Therefore, we focused on the groove between lumbar paraspinal muscles as a simple index for evaluating paraspinal muscle degeneration.

METHODS

A total of 160 subjects aged 10 to 88 years (10 male and 10 female subjects in each decade) with lumbar lordosis of more than 20° were included. Body mass index (BMI) was calculated. Sagittal T2-weighted magnetic resonance imaging (MRI) was used to measure lumbar lordosis, while axial T2-weighted MRI was used to measure cross-sectional area (CSA) and fat infiltration rate of the paraspinal muscles at the intervertebral disc level from L1 to L5. To quantify the depth of the groove between the paraspinal muscles, our own image index (lumbar indentation value (LIV): equal to the length of the bulge of the muscle to the attachment of the spinous process), also was measured. We then determined the correlation between LIV and paraspinal muscle degeneration.

RESULTS

There were no significant differences in BMI and lumbar lordosis between age groups. CSA of the paraspinal muscles tended to decrease with age, and fat infiltration rate increased with age. There was a negative correlation between CSA and fat infiltration rate at all levels (r = -0.474 to -0.634). LIV decreased significantly with age and strongly correlated with CSA at all levels (r = 0.709-0.789).

CONCLUSION

Our new index is a simple and effective parameter for evaluating paraspinal muscle degeneration associated with aging.

LEVEL OF EVIDENCE

4.

Back pain was less explained than leg pain: a cross-sectional study using magnetic resonance imaging in low back pain patients with and without radiculopathy

BACKGROUND

Cross-sectional studies have shown associations between lumbar degenerative manifestations on magnetic resonance imaging (MRI) and low back pain (LBP). Disc herniations and other degenerative manifestations, however, frequently occur in asymptomatic individuals. The purpose of this cross-sectional study was to analyze for associations between pain intensity and degenerative manifestations and other pain variables in patients for whom prognostic factors have been published previously.

METHODS

Included were 141 consecutive patients with and without radiculopathy, all sick-listed 1-4 months due to low back pain and subsequently examined by MRI of the lumbar spine. Using different methods of grouping the degenerative manifestations, linear regression analyses were performed with the intensity of back + leg pain, back pain and leg pain as dependent variables covering actual pain and pain the preceding 2 weeks. The clinical classification into +/- radiculopathy was established before and independently of the standardised description of MRI findings.

RESULTS

Radiculopathy was present in 43 % of the patients. Pain was best explained using rank-ordered degenerative manifestations on MRI. Back pain and leg pain were differently associated, and back pain was less explained than leg pain in the multivariate analyses (15 % vs. 31 % of the variation). Back pain intensity was higher in patients with type 1 Modic changes and in some patients with nerve root touch, but was not associated with disc herniations. Leg pain intensity was well explained by disc herniations causing MRI nerve root compromise and radiculopathy. In patients with radiculopathy, nerve root touch caused as much leg pain as nerve root displacement or compression. High intensity zones and osteophytes were not associated with back pain, but only associated with leg pain in patients with radiculopathy. Tender points explained some of the back pain, and widespread pain explained leg pain in some of the patients without radiculopathy.

CONCLUSIONS

Back pain was associated with type 1 Modic changes, nerve root touch and tender points, whereas leg pain was associated with osteophytes, HIZ, disc herniation, all sorts of MRI nerve root compromise, radiculopathy and widespread pain.