Prevalence of facet joint degeneration in association with intervertebral joint degeneration in a sample of organ donors

Mechanical crosstalk between the intervertebral disc, facet joints, and vertebral endplate following acute disc injury in a rabbit model

Background

Vertebral endplate sclerosis and facet osteoarthritis have been documented in animals and humans. However, it is unclear how these adjacent pathologies engage in crosstalk with the intervertebral disc. This study sought to elucidate this crosstalk by assessing each compartment individually in response to acute disc injury.

Methods

Eleven New Zealand White rabbits underwent annular disc puncture using a 16G or 21G needle. At 4 and 10 weeks, individual compartments of the motion segment were analyzed. Discs underwent T 1 relaxation mapping with MRI contrast agent gadodiamide as well T 2 mapping. Both discs and facets underwent mechanical testing via vertebra-disc-vertebra tension-compression creep testing and indentation testing, respectively. Endplate bone density was quantified via μCT. Discs and facets were sectioned and stained for histology scoring.

Results

Intervertebral discs became more degenerative with increasing needle diameter and time post-puncture. Bone density also increased in endplates adjacent to both 21G and 16G punctured discs leading to reduced gadodiamide transport at 10 weeks. The facet joints, however, did not follow this same trend. Facets adjacent to 16G punctured discs were less degenerative than facets adjacent to 21G punctured discs at 10 weeks. 16G facets were more degenerative at 4 weeks than at 10, suggesting the cartilage had recovered. The formation of severe disc osteophytes in 16G punctured discs between 4 and 10 weeks likely offloaded the facet cartilage, leading to the recovery observed.

Conclusions

Overall, this study supports that degeneration spans the whole spinal motion segment following disc injury. Vertebral endplate thickening occurred in response to disc injury, which limited the diffusion of small molecules into the disc. This work also suggests that altered disc mechanics can induce facet degeneration, and that extreme bony remodeling adjacent to the disc may promote facet cartilage recovery through offloading of the articular cartilage.

Lumbar facet joint arthrosis on magnetic resonance imaging and its association with low back pain in a selected Ghanaian population

Objectives

Facet joint arthrosis is a common radiologic finding but remains controversial as a source of low back pain. We conducted a study to evaluate some of the potential risk factors contributing to the development of facet joint arthrosis, such as age, gender, and body mass index (BMI). The study aimed at establishing an association between these factors and facet joint arthrosis in the Ghanaian population, as a foundation for further research on low back pain.

Materials and Methods

This was a retrospective study done at the Department of Radiology, Korle Bu Teaching Hospital from January 2019 to December 2021. The study population included all cases referred to our department with complaints of low back pain. Patients below 18 years and those with a history of congenital lesions, trauma, infection, and malignancies were excluded. A total of 1017 cases were identified with facet joint arthrosis. The mean difference in age and BMI between males and females was compared using an independent sample t-test. Statistical association was done using Pearson's Chi-square test. P ≤ 0.05 was used as statistical significance.

Results

Majority of the study subjects were overweight with a mean BMI of 27.31 ± 5.37 kg/m2. The mean age was 53.61 ± 16.22 years, and majority were within the age of 51-60 years. Age was significantly associated with the prevalence of facet joint arthrosis.

Conclusion

The prevalence of facet joint arthrosis is significantly associated with increasing age but not with the BMI. Lumbar facet joint arthrosis is more prevalent in women than in men, which may be due to the sensitivity of cartilage to female sex hormones.

The Lumbar Facet Capsular Ligament Becomes More Anisotropic and the Fibers Become Stiffer With Intervertebral Disc and Facet Joint Degeneration

Degeneration of the lumbar spine, and especially how that degeneration may lead to pain, remains poorly understood. In particular, the mechanics of the facet capsular ligament may contribute to low back pain, but the mechanical changes that occur in this ligament with spinal degeneration are unknown. Additionally, the highly nonlinear, heterogeneous, and anisotropic nature of the facet capsular ligament makes understanding mechanical changes more difficult. Clinically, magnetic resonance imaging (MRI)-based signs of degeneration in the facet joint and the intervertebral disc (IVD) correlate. Therefore, this study examined how the nonlinear, heterogeneous mechanics of the facet capsular ligament change with degeneration of the lumbar spine as characterized using MRI. Cadaveric human spines were imaged via MRI, and the L2-L5 facet joints and IVDs were scored using the Fujiwara and Pfirrmann grading systems. Then, the facet capsular ligament was isolated and biaxially loaded. The nonlinear mechanical properties of the ligament were obtained using a nonlinear generalized anisotropic inverse mechanics analysis (nGAIM). Then a Holzapfel-Gasser-Ogden (HGO) model was fit to the stress-strain data obtained from nGAIM. The facet capsular ligament is stiffer and more anisotropic at larger Pfirrmann grades and higher Fujiwara scores than at lower grades and scores. Analysis of ligament heterogeneity showed all tissues are highly heterogeneous, but no distinct spatial patterns of heterogeneity were found. These results show that degeneration of the lumbar spine including the facet capsular ligament appears to be occurring as a whole joint phenomenon and advance our understanding of lumbar spine degeneration.

Axial rotation and pain are associated with facet joint osteoarthritis in Adolescent Idiopathic Scoliosis

OBJECTIVE

Facet joints are crucial for spinal stability and develop premature osteoarthritis in patients with adolescent idiopathic scoliosis (AIS). Here, we evaluated the association between facet joint cartilage and subchondral bone homeostasis, perceived back pain and 3-dimensional spinal deformity to understand better the role of facet joint degeneration in AIS progression and pain.

METHOD

Cartilage and bone osteoarthritic states of AIS facet joint surgical samples were characterized using histological OARSI scoring, visual morphological grading and μCT analysis, respectively. Back pain was self-reported using a numerical rating scale and expressed relative to the location on the patient's back. The scoliotic curves from our patient cohort were digitally reconstructed using biplanar radiographs and the eOS system (EOS imaging). The deformity was then reduced to 3 intervertebral angles (coronal, sagittal and axial) for each pair of bilateral facet joints. Statistical associations between the intervertebral angles, osteoarthritis parameters and pain intensity were performed using the Spearman method and Friedman test.

RESULTS

Facet joint cartilage degeneration was associated with decreased subchondral bone volume and quality. Most importantly, asymmetrical, and overall degeneration of facet joints was strongly correlated to intervertebral axial rotation. Additionally, kyphotic intervertebral segments in the sagittal plane were good predictors of increased facet joint degeneration and back pain.

CONCLUSION

Facet joint degeneration is associated with axial deformity, kyphotic intervertebral angle and back pain intensity in AIS. These results suggest that facet joints are important features to consider for rotational instability in AIS spines and related disease progression and perceived back pain.

Long-term whole-body vibration induces degeneration of intervertebral disc and facet joint in a bipedal mouse model

Background: Whole body vibration (WBV) has been used to treat various musculoskeletal diseases in recent years. However, there is limited knowledge about its effects on the lumbar segments in upright posture mice. This study was performed to investigate the effects of axial Whole body vibration on the intervertebral disc (IVD) and facet joint (FJ) in a novel bipedal mouse model.

Methods: Six-week-old male mice were divided into control, bipedal, and bipedal + vibration groups. Taking advantage of the hydrophobia of mice, mice in the bipedal and bipedal + vibration groups were placed in a limited water container and were thus built standing posture for a long time. The standing posture was conducted twice a day for a total of 6 hours per day, 7 days per week. Whole body vibration was conducted during the first stage of bipedal building for 30 min per day (45 Hz with peak acceleration at 0.3 g). The mice of the control group were placed in a water-free container. At the 10th-week after experimentation, intervertebral disc and facet joint were examined by micro-computed tomography (micro-CT), histologic staining, and immunohistochemistry (IHC), and gene expression was quantified using real-time polymerase chain reaction. Further, a finite element (FE) model was built based on the micro-CT, and dynamic Whole body vibration was loaded on the spine model at 10, 20, and 45 Hz.

Results: Following 10 weeks of model building, intervertebral disc showed histological markers of degeneration, such as disorders of annulus fibrosus and increased cell death. Catabolism genes’ expression, such as Mmp13, and Adamts 4/5, were enhanced in the bipedal groups, and Whole body vibration promoted these catabolism genes’ expression. Examination of the facet joint after 10 weeks of bipedal with/without Whole body vibration loading revealed rough surface and hypertrophic changes at the facet joint cartilage resembling osteoarthritis. Moreover, immunohistochemistry results demonstrated that the protein level of hypertrophic markers (Mmp13 and Collagen X) were increased by long-durationstanding posture, and Whole body vibration also accelerated the degenerative changes of facet joint induced by bipedal postures. No changes in the anabolism of intervertebral disc and facet joint were observed in the present study. Furthermore, finite element analysis revealed that a larger frequency of Whole body vibration loading conditions induced higher Von Mises stresses on intervertebral disc, contact force, and displacement on facet joint.

Conclusion: The present study revealed significant damage effects of Whole body vibration on intervertebral disc and facet joint in a bipedal mouse model. These findings suggested the need for further studies of the effects of Whole body vibration on lumbar segments of humans.

Intervertebral disc degeneration and osteoarthritis: a common molecular disease spectrum

Intervertebral disc degeneration (IDD) and osteoarthritis (OA) affecting the facet joint of the spine are biomechanically interdependent, typically occur in tandem, and have considerable epidemiological and pathophysiological overlap. Historically, the distinctions between these degenerative diseases have been emphasized. Therefore, research in the two fields often occurs independently without adequate consideration of the co-dependence of the two sites, which reside within the same functional spinal unit. Emerging evidence from animal models of spine degeneration highlight the interdependence of IDD and facet joint OA, warranting a review of the parallels between these two degenerative phenomena for the benefit of both clinicians and research scientists. This Review discusses the pathophysiological aspects of IDD and OA, with an emphasis on tissue, cellular and molecular pathways of degeneration. Although the intervertebral disc and synovial facet joint are biologically distinct structures that are amenable to reductive scientific consideration, substantial overlap exists between the molecular pathways and processes of degeneration (including cartilage destruction, extracellular matrix degeneration and osteophyte formation) that occur at these sites. Thus, researchers, clinicians, advocates and policy-makers should consider viewing the burden and management of spinal degeneration holistically as part of the OA disease continuum.

Level dependent alterations in human facet cartilage mechanics and bone morphometry with spine degeneration

The zygapophyseal joints of the spine, also known as the facet joints, are paired diarthrodial joints posterior to the intervertebral disc and neural elements. The pathophysiology of facet osteoarthritis (OA), as well as crosstalk between the disc and facets, remains largely understudied compared to disc degeneration. The purpose of this study was to characterize alterations to human facet cartilage and subchondral bone across a spectrum of degeneration and to investigate correlations between disc and facet degeneration. Human lumbar facet articular surfaces from six independent donors were subject to creep indentation mechanical testing to quantify cartilage mechanical properties, followed by microcomputed tomography (µCT) analyses for subchondral bone morphometry. The degenerative state of each articular surface was assessed via macroscopic scoring and via Osteoarthritis Research Society International histopathology scoring. Our data suggest reduced facet cartilage compressive and tensile moduli and increased permeability with increasing degenerative grade, particularly at the lower levels of the spine. µCT analyses revealed spinal level-dependent alterations to the subchondral bone, with an increase in trabecular bone at the L4-L5 level, but a decrease at the upper levels of the lumbar spine with increasing degenerative grade. Cortical bone volume fraction was generally decreased with increasing degenerative grade across spinal levels. Correlation analysis revealed several associations between quantitative measures of disc degeneration and facet OA. This study showed that alterations in the mechanical properties of facet cartilage and in the structural properties of facet subchondral bone correlated with aspects of disc degeneration and were highly dependent on spinal level.

Facet Joint Syndrome: Pathophysiology, Diagnosis, and Treatment

Facet joint osteoarthritis (OA) is the most frequent form of facet joint syndrome. Medical history, referred pain patterns, physical examination, and diagnostic imaging studies (standard radiographs, magnetic resonance imaging, computed tomography and single-photon emission computed tomography) may suggest but not confirm lumbar facet joint (LFJ) syndrome as a source of low back pain (LBP). However, the diagnosis and treatment of facet joint syndrome is still controversial and needs further study. It is widely acknowledged that block with local anesthetic is perhaps the most effective method to establish a diagnosis of pain from LFJ. Particularly, there are different rates of success among different populations selected for diagnostic block with various positive criteria. Currently, in addition to conservative treatments for pain such as painkillers, functional exercises, and massage, there are many other methods, including block, denervation of the nerves that innervate the joints by radiofrequency, freezing or endoscopy, and injections. Due to the limited duration of pain relief from neurolysis of medial branch, many scholars have recently turned their targets to dorsal roots and LFJ capsules. Therefore, we reviewed the latest research progress of facet joint syndrome from diagnosis to treatment.

Chronology of disc degeneration and facet joint arthritis in lumbar spine is variable - A CT based cross-sectional study

BACKGROUND

The notion that disc degeneration (DD) always precedes facet joint arthritis (FJA) has held sway for many decades. However, it is not always the case. We hypothesized that DD is not always the first offender studied the prevalence of isolated DD and isolated FJA in the lumbar spine.

METHODS

Inter-vertebral discs and bilateral facet joints of lumbar spines of 135 participants were graded. The participants were divided into one of the four categories. 'No degeneration,' 'Isolated disc degeneration without facet joint arthritis,' 'Combined disc degeneration and facet joint arthritis,' and 'Isolated facet joint arthritis without disc degeneration.' Multivariate logistic regression analysis was done to evaluate the predictive factors for spinal degeneration using FJA as a dependent variable while age, sex, BMI, smoking history, and DD as predictor variables.

RESULTS

The majority of participants had isolated FJA 64 (47.4%). Combined DD and FJA were noted in 32 (23.7%), isolated DD in 8 (5.9%), while 31(23%) had no degeneration. Only age was found to be significantly contributing to the prediction model in multivariate analysis.

CONCLUSION

Our study shows that spinal degeneration may begin either in the disc or in the facet joints depending upon the aetiological factors. It is a vicious circle that may be entered at any point, FJA or DD.

Lower effectiveness of facet joint infiltration in patients with concurrent facet joint degeneration and active endplate changes

BACKGROUND CONTEXT

Facet joint degeneration (FJD) and disc degeneration (DD) with associated endplate (EP) changes, specifically Modic 1 changes, might occur concurrently and therefore pose a challenge in the treatment of lower back pain (LBP).

PURPOSE

The aim of the present study was to investigate if the presence of active EP changes (Modic 1) would alter the effect of facet joint infiltrations (FJI) for the treatment of concurrent FJD.

STUDY DESIGN

Prospective cohort study, Level III.

PATIENT SAMPLE

42 patients (Male:20, Female:22) with an average of 58±14 years with FJD on conventional magnetic resonance imaging (MRI) receiving a FJI for treatment of lower back pain were included.

OUTCOME MEASURES

The pain score at baseline, 15 min, 1 day, 1 week and 1 month following FJI as well as the reduction of pain were analyzed. Furthermore, active EP changes on conventional MRI and increased EP metabolic activity on PET/MRI were evaluated and compared.

METHODS

All the patients underwent a (18F)-NaF PET/MRI, conventional MRI and FJI for symptomatic FJD. Active EP changes on conventional MRI and increased EP metabolic activity on PET/MR were analyzed for conformity. The pain score as well as the pain reduction at the above-mentioned time points were compared between patients with and without increased EP metabolic activity in PET/MRI.

RESULTS

The LBP reduction was significantly different between patients with (n=20) and without (n=22) active EP changes at 15 minutes (1.3±2.4 vs. 2.9±2.4, p=.03) and 1 month (0.9±2.3 vs. 2.8±2.9, p<.001) following FJI. The minimal clinically important difference for LBP reduction was reached significantly more often in the absence of active EP changes (73%) compared with patients with active EP changes (35%) 1 month following FJI (p=.03).

CONCLUSIONS

FJI is less effective in LBP reduction of patients with FJD and concurrent active EP changes (eg Modic 1).

Upregulation of P2Y12 inhibits chondrocyte apoptosis in lumbar osteoarthritis through the PI3K/AKT signaling pathway

Lumbar facet osteoarthritis (FJOA) is a major cause of severe lower back pain and disability worldwide. However, the mechanism underlying cartilage degeneration in FJOA remains unclear. The purpose of this study was to investigate the regulation and mechanism of P2Y12 on chondrocyte apoptosis in FJOA. The experimental rats were randomly divided into non-operation (n = 20) and operation groups (n = 20). In the operation group, Sodium iodoacetate (MIA, Sigma, 200 mg/mL) was injected into the right L4/5 facet process using a blunt nanoneedle 26 (WPI, Sarasota, FL, USA) under the control of an injection pump. The final injection volume was 5µL and the injection rate was 2µL/min. The facet joint was removed four weeks after surgery. After the operation, samples were stored at -80 °C until further use, whereby the right facet joints in each group were tested. Hematoxylin and eosin (HE) and iron-red solid green staining were used to observe the degeneration of articular chondrocytes in rats. Immunohistochemistry and western blotting were used to observe the expressions of P2Y12, Matrix metalloproteinase 13 (MMP13), Collagen II (COL2), and other cartilage degeneration and apoptosis-related genes. Co-localization of P2Y12-cleaved caspase-3 in the apoptosis model was detected by dual-standard immunofluorescence staining. Apoptosis was also detected by flow cytometry and TUNEL assay.P2Y12 is highly expressed in OA cartilage tissue, and inhibits IL-1β -induced chondrocyte apoptosis through PI3K/AKT signaling pathway, thus playing a certain protective role on cartilage.

The Association of MRI Findings and Long-Term Disability in Patients With Chronic Low Back Pain

STUDY DESIGN

Longitudinal cohort study with 13-year follow-up.

OBJECTIVE

To assess whether long-term disability is associated with baseline degenerative magnetic resonance imaging (MRI) findings in patients with low back pain (LBP).

METHODS

In 2004-2005, patients aged 18 to 60 years with chronic LBP were enrolled in a randomized controlled trial and lumbar MRI was performed. Patients completed the Roland-Morris Disability Questionnaire (RMDQ) and the LBP Rating Scale, at baseline and 13 years after the MRI. Multivariate regression analysis was performed with 13-year RMDQ as the dependent variable and baseline disc degeneration (DD, Pfirrmann grade), Modic changes (MC), facet joint degeneration (FJD, Fujiwara grade) smoking status, body mass index, and self-reported weekly physical activity at leisure as independent variables.

RESULTS

Of 204 patients with baseline MRI, 170 (83%) were available for follow-up. Of these, 88 had Pfirrmann grade >III (52%), 67 had MC (39%) and 139 had Fujiwara grade >2 (82%) on at least 1 lumbar level. Only MC (β = -0.15, P = .031) and weekly physical activity at leisure (β = -0.51, P < .001) were significantly, negatively, associated with 13-year RMDQ-score (R² = 0.31).

CONCLUSION

DD and FJD were not associated with long-term disability. Baseline MC and weekly physical activity at leisure were statistically significantly associated with less long-term disability.

Pathomechanism and Biomechanics of Degenerative Disc Disease: Features of Healthy and Degenerated Discs

The human intervertebral disc (IVD) is a complex organ composed of fibrous and cartilaginous connective tissues, and it serves as a boundary between 2 adjacent vertebrae. It provides a limited range of motion in the torso as well as stability during axial compression, rotation, and bending. Adult IVDs have poor innate healing potential due to low vascularity and cellularity. Degenerative disc disease (DDD) generally arises from the disruption of the homeostasis maintained by the structures of the IVD, and genetic and environmental factors can accelerate the progression of the disease. Impaired cell metabolism due to pH alteration and poor nutrition may lead to autophagy and disruption of the homeostasis within the IVD and thus plays a key role in DDD etiology. To develop regenerative therapies for degenerated discs, future studies must aim to restore both anatomical and biomechanical properties of the IVDs. The objective of this review is to give a detailed overview about anatomical, radiological, and biomechanical features of the IVDs as well as discuss the structural and functional changes that occur during the degeneration process.

Intervertebral disc degeneration and regeneration: a motion segment perspective

Back and neck pain have become primary reasons for disability and healthcare spending globally. While the causes of back pain are multifactorial, intervertebral disc degeneration is frequently cited as a primary source of pain. The annulus fibrosus (AF) and nucleus pulposus (NP) subcomponents of the disc are common targets for regenerative therapeutics. However, disc degeneration is also associated with degenerative changes to adjacent spinal tissues, and successful regenerative therapies will likely need to consider and address the pathology of adjacent spinal structures beyond solely the disc subcomponents. This review summarises the current state of knowledge in the field regarding associations between back pain, disc degeneration, and degeneration of the cartilaginous and bony endplates, the AF-vertebral body interface, the facet joints and spinal muscles, in addition to a discussion of regenerative strategies for treating pain and degeneration from a whole motion segment perspective.

Medical ozone therapy in facet joint syndrome: an overview of sonoanatomy, ultrasound-guided injection techniques and potential mechanism of action

Facet joint osteoarthritis is the most prevalent source of facet joint pain and represents a significant cause of low back pain. Oxygen-ozone therapy has been shown to have positive results in acute and chronic spinal degeneration diseases and it could be a safe and efficacious alternative to traditional facet joint conservative treatments. This review article explains the interventional facet joint management with ultrasound-guided oxygen-ozone therapy, providing an anatomy/sonoanatomy overview of lumbar facet joints and summarizing the potential mechanism of action of oxygen-ozone in the treatment of facet joint osteoarthritis, not yet fully understood.

Toll-like receptor involvement in adolescent scoliotic facet joint degeneration

Facet joint osteoarthritis is prevalent in young patients with adolescent idiopathic scoliosis (AIS) and might contribute to back pain. Toll-like receptors (TLR) have been linked to cartilaginous tissue degeneration but their involvement in facet joint osteoarthritis in AIS patients is still unknown. We compared baseline gene expression levels of TLRs -1, -2, -4, and -6 in scoliotic and non-scoliotic chondrocytes and found higher expression levels in scoliotic chondrocytes with significantly higher TLR2 levels. Furthermore, TLR expression correlated strongly and significantly with inflammatory and catabolic markers in scoliotic but not in non-scoliotic chondrocytes. TLR activation with a synthetic TLR2/6 agonist resulted in a robust induction and release of pro-inflammatory and catabolic factors which exacerbated proteoglycan loss in scoliotic but not in non-scoliotic cartilage. We also detected a higher abundance of alarmins including S100A8/9 and biglycan in scoliotic cartilage. Finally, the small-molecule antagonists Sparstolonin B and o-Vanillin reduced catabolism following induction with naturally occurring alarmins and the synthetic TLR2/6 agonist. The high baseline expression, robust responsiveness and strong and significant correlation with proteases and pro-inflammatory cytokines suggest that TLRs are key regulators of facet joint degeneration in AIS. Blocking their activity could therefore potentially modify disease progression.

Consensus practice guidelines on interventions for lumbar facet joint pain from a multispecialty, international working group

BACKGROUND

The past two decades have witnessed a surge in the use of lumbar facet blocks and radiofrequency ablation (RFA) to treat low back pain (LBP), yet nearly all aspects of the procedures remain controversial.

METHODS

After approval by the Board of Directors of the American Society of Regional Anesthesia and Pain Medicine, letters were sent to a dozen pain societies, as well as representatives from the US Departments of Veterans Affairs and Defense. A steering committee was convened to select preliminary questions, which were revised by the full committee. Questions were assigned to 4-5 person modules, who worked with the Subcommittee Lead and Committee Chair on preliminary versions, which were sent to the full committee. We used a modified Delphi method, whereby the questions were sent to the committee en bloc and comments were returned in a non-blinded fashion to the Chair, who incorporated the comments and sent out revised versions until consensus was reached.

RESULTS

17 questions were selected for guideline development, with 100% consensus achieved by committee members on all topics. All societies except for one approved every recommendation, with one society dissenting on two questions (number of blocks and cut-off for a positive block before RFA), but approving the document. Specific questions that were addressed included the value of history and physical examination in selecting patients for blocks, the value of imaging in patient selection, whether conservative treatment should be used before injections, whether imaging is necessary for block performance, the diagnostic and prognostic value of medial branch blocks (MBB) and intra-articular (IA) injections, the effects of sedation and injectate volume on validity, whether facet blocks have therapeutic value, what the ideal cut-off value is for a prognostic block, how many blocks should be performed before RFA, how electrodes should be oriented, the evidence for larger lesions, whether stimulation should be used before RFA, ways to mitigate complications, if different standards should be applied to clinical practice and clinical trials and the evidence for repeating RFA (see table 12 for summary).

CONCLUSIONS

Lumbar medial branch RFA may provide benefit to well-selected individuals, with MBB being more predictive than IA injections. More stringent selection criteria are likely to improve denervation outcomes, but at the expense of more false-negatives. Clinical trials should be tailored based on objectives, and selection criteria for some may be more stringent than what is ideal in clinical practice.

Evaluation of MRI and CT parameters to analyze the correlation between disc and facet joint degeneration in the lumbar three-joint complex

Lumbar 3-joint complex degeneration is a multifactorial, pathological process. Previous studies included insufficient quantitative analyses to prove the relationship between disc degeneration and facet joint osteoarthritis (OA). We assessed the correlation between intervertebral disc and lumbar facet joint degeneration using computed tomography (CT) and magnetic resonance imaging (MRI) parameters.A total of 152 participants who underwent conventional MRI and CT in the clinostat position were included in this study. The presence of lumbar disc degeneration was identified using the Pfirrmann grading system, and the presence of lumbar facet joint degeneration was identified using the Weishaupt grading system. Facet tropism was defined as a divergence more than 7° between the facet joint angles of both sides at the same segment. The intervertebral disc heights were also measured.Most facet joint OA probably appeared at the segment with intervertebral disc degeneration of more than grade III. Facet joint OA was significantly exacerbated with the progression of disc degeneration grade. The intervertebral height significantly decreased with the progression of facet joint degeneration grades, except for grades 0 and 1.Our current study found that each individual joint degeneration influences the other 2 in the lumbar 3-joint complex. Facet tropism was significantly associated with lumbar disc degeneration. Narrowing of the intervertebral disc height probably aggravates the facet joint degeneration further at the same level.

Development and Characterization of a Novel Bipedal Standing Mouse Model of Intervertebral Disc and Facet Joint Degeneration

BACKGROUND

Intervertebral disc degeneration is a major cause of chronic low back pain, and excessive loading contributes to intervertebral disc degeneration. However, the lack of an effective bipedal in vivo animal model limits research about this condition.

QUESTIONS/PURPOSES

To evaluate the utility of a new type of bipedal standing mouse model for intervertebral disc degeneration, we asked: (1) Are there spinal degeneration changes in bipedal mice as determined by lumbar disc height, histologic features, and immunohistochemistry measures compared with control mice? (2) Are the bipedal mice comparable to aged mice for simulating the spinal degeneration caused by increased stress?

METHODS

Thirty-two 8-week-old male C57BL/6 mice were divided into experimental and control groups. Based on their hydrophobia, mice in the experimental group were placed in a limited water-containing space (5 mm deep) and were thereby induced to actively take a bipedal standing posture. This was conducted twice a day for a total of 6 hours a day, 7 days a week. Control mice were similarly placed in a limited but water-free space. Video surveillance was used to calculate the percentage of time spent in the bipedal stance for the two groups of mice. Compared with the control group, the percentage of time standing on both feet in the experimental group was higher (48% ± 5%, 95% confidence interval [CI], 42%-54% versus 95% ± 1%, 95% CI, 92%-97%; p < 0.001). Eight mice from both groups were then randomly euthanized at either 6 or 10 weeks and lumbar spine specimens (L3-L6) were collected. The lumbar disc height index (DHI%) of the two groups was compared using micro-CT measurements, and the extent of disc degeneration was assessed based on histologic staining (cartilage endplate height, disc degeneration score) and by immunohistochemistry (Col2a1,CollagenX, matrix metalloprotease-13 [MMP-13], osteocalcin [OCN]). In addition, the histopathologic features of spinal degeneration were compared with 12- and 18-month-old mice. A p value < 0.05 indicated a significant difference.

RESULTS

Lumbar disc degeneration was aggravated after 10 weeks with the DHI% decreasing (5.0% ± 0.4%; 95% CI, 4.6%-5.5% versus 4.6 ± 0.3%; 95% CI, 4.3%-4.9%; p = 0.011). Histologically, the cartilage endplate height of the experimental group was decreased compared with the control group (30 ± 6 μm; 95% CI, 24-37 μm versus 70 ± 7 μm; 95% CI, 63-79 μm; p < 0.001), and the disc degeneration score was increased (5 ± 1; 95% CI, 4-6 versus 1 ± 1; 95% CI, 0-2; p < 0.001). Expression of Col2a1, vimentin, and aggrecan in the experimental group was decreased compared with the control group, whereas the expressions of collagen X (60% ± 2%; 95% CI, 55%-66% versus 19% ± 3%; 95% CI, 17%-24%; p < 0.001), MMP-13 (54% ± 8%; 95% CI, 49%-61% versus 1% ± 1%; 95% CI, 1%-2%; p < 0.001), and OCN (41% ± 3%; 95% CI, 34%-49% versus 5% ± 1%; 95% CI, 2%-7%, p < 0.001) were increased. The spine degeneration caused by this model was primarily manifested in the degeneration of the annulus fibrosus and facet joints compared with aged mice, whereas the degree of degeneration in the nucleus pulposus tissue and cartilage endplates was mild.

CONCLUSIONS

We believe we have established a noninvasive and effective in vivo bipedal mouse model for studying disc degeneration and biologic signal transduction comparable to that seen in intervertebral disc degeneration.

CLINICAL RELEVANCE

This in vivo mouse model of intervertebral disc degeneration can simulate the pathogenesis of spinal degeneration caused by increased stress and this can be used to study questions such as disc herniation in young adults.

Relationship between facet joint tropism and degeneration of facet joints and intervertebral discs based on a histological study

Purpose

Evaluate the correlation between lumbar facet joint tropism, lumbar facet joint degeneration, and intervertebral disc degeneration.

Methods

Forty-two of facet joints were evaluated histologically and radiologically.

Results

The correlation between facet joint tropism and histologic, CT, and MRI grading was -0.159 (P = 0.339), 0.025 (P = 0.226) and -0.270 (P = 0.102), respectively. The correlation between facet joint tropism and intervertebral disc MRI grading was 0.346 (P = 0.033), and that between facet joint and intervertebral disc MRI grading was 0.208 (P = 0.210).

Conclusions

Facet joint tropism was correlated with intervertebral disc degeneration but not with facet joint degeneration.

Correlations between Modic change and degeneration in 3-joint complex of the lower lumbar spine: A retrospective study

BACKGROUND

Modic changes (MCs) associated with low back pain (LBP) have been assessed in a few studies. It has been documented that patients with LBP have MCs in a specific segment, but the relationship between facet joint or disc degeneration and MCs is still disputed. Thus, we aimed to evaluate the correlation between MC and facet joint or disc degeneration using imaging.

METHODS

Imaging data of patients were retrospectively analyzed at the Orthopedic Department of the First Affiliated Hospital of Nanchang from January 2014 to August 2017. MCs, facet joint degeneration, and disc degeneration in L3-S1 were evaluated by lumbar MRI. χ test and contingency correlation coefficient were used for the statistical analyses, and a P value < .05 was considered statistically significant.

RESULTS

In the descriptive statistical analysis, MCs were found to have the highest incidence in the L4-5 segment. Type II MCs had a higher incidence than type I and type III MCs regardless of whether they were in the L3-4, L4-5, or L5-S1 segment. On one hand, MCs were more frequently distributed in grades 3, 4, and 5 of the degenerative lumbar discs regardless of whether they were in the L3-4, L4-5, or L5-S1 segment (P < .000, V: contingency coefficient >0); particularly, type II MCs were closely related to lumbar disc degeneration (P < .05, V > 0). On the other hand, MCs were more frequently distributed in grades 1, 2, and 3 of the degenerative lumbar facet regardless of whether they were in the L3-4, L4-5, or L5-S1 segment (P < .05, V > 0). Particularly, type II MCs were frequently distributed in grades 1, 2, and 3 of the facet joint in the L4-5 and L5-S1 segments (P < .05, V > 0).

CONCLUSION

MCs are correlated with the grade of lumbar spine degeneration, including lumbar disc and facet joint degeneration. MCs, especially type II, frequently occurred in severe degeneration of the lumbar disc and facet joint. Thus, MC may be one of the manifestations of lumbar disc and facet joint degeneration.

Facet Joints of the Spine: Structure–Function Relationships, Problems and Treatments, and the Potential for Regeneration

The zygapophysial joint, a diarthrodial joint commonly referred to as the facet joint, plays a pivotal role in back pain, a condition that has been a leading cause of global disability since 1990. Along with the intervertebral disc, the facet joint supports spinal motion and aids in spinal stability. Highly susceptible to early development of osteoarthritis, the facet is responsible for a significant amount of pain in the low-back, mid-back, and neck regions. Current noninvasive treatments cannot offer long-term pain relief, while invasive treatments can relieve pain but fail to preserve joint functionality. This review presents an overview of the facet in terms of its anatomy, functional properties, problems, and current management strategies. Furthermore, this review introduces the potential for regeneration of the facet and particular engineering strategies that could be employed as a long-term treatment.

Comparative Analysis of Bone Structural Parameters Reveals Subchondral Cortical Plate Resorption and Increased Trabecular Bone Remodeling in Human Facet Joint Osteoarthritis

Facet joint osteoarthritis is a prominent feature of degenerative spine disorders, highly prevalent in ageing populations, and considered a major cause for chronic lower back pain. Since there is no targeted pharmacological therapy, clinical management of disease includes analgesic or surgical treatment. The specific cellular, molecular, and structural changes underpinning facet joint osteoarthritis remain largely elusive. The aim of this study was to determine osteoarthritis-related structural alterations in cortical and trabecular subchondral bone compartments. To this end, we conducted comparative micro computed tomography analysis in healthy (n = 15) and osteoarthritic (n = 22) lumbar facet joints. In osteoarthritic joints, subchondral cortical plate thickness and porosity were significantly reduced. The trabecular compartment displayed a 42 percent increase in bone volume fraction due to an increase in trabecular number, but not trabecular thickness. Bone structural alterations were associated with radiological osteoarthritis severity, mildly age-dependent but not gender-dependent. There was a lack of association between structural parameters of cortical and trabecular compartments in healthy and osteoarthritic specimens. The specific structural alterations suggest elevated subchondral bone resorption and turnover as a potential treatment target in facet joint osteoarthritis.

Characterization of facet joint cartilage properties in the human and interspecies comparisons

The facet joint, a synovial joint located on the posterior-lateral spine, is highly susceptible to degenerative changes and plays a significant role in back-related morbidities. Despite its significance, the facet is rarely studied and thus current treatment strategies are lacking. This study aimed to characterize, for the first time, the properties of human, pig, monkey, and rabbit lumbar facet cartilage providing much-needed design criteria for tissue engineering approaches. In this study, where possible, the facet's morphological, histological, mechanical, and biochemical properties were evaluated. Comparisons between the properties of the inferior and superior facet surfaces, as well as among spinal levels were performed within each species. In addition, interspecies comparisons of the properties were determined. The human facet joint was found to be degenerated; 100% of joint surfaces showed signs of pathology and approximately 71% of these were considered to be grade 4. Joint morphology varied among species, demonstrating that despite the mini-pig facet being closest to the human in terms of width and length, it was far more curved than the human or any of the other species. No notable differences were found in the mini-pig, monkey, and rabbit mechanical and biochemical properties, suggesting that these species, despite morphological differences, may serve as suitable animal models for studying structure-function relationships of the human facet joint. The characterization data reported in this study may increase our understanding of this ill-described joint as well as provide the foundation for the development of new treatments such as tissue engineering.

STATEMENT OF SIGNIFICANCE

This work provides the first comprehensive description of the properties of lumbar facet joint cartilage. Importantly, this work establishes that histological, biochemical, and mechanical properties are comparable between bipedal and quadrupedal animals, helping to guide future selection of appropriate animal models. This work also suggests that the human facet joint is highly susceptible to pathology. The mechanical properties of facet cartilage, found to be inferior to those of other synovial joints, provide a greater understanding of the joint's structure-function relationships as well as the potential etiology of facet joint pathology. Lastly, this work will serve as the foundation for the development of much-needed facet joint treatments, especially those based on tissue engineering approaches.

Interventional therapies for chronic low back pain

OBJECTIVE

Low back pain (LBP) is a highly prevalent condition and one of the leading causes of lost productivity and health-care costs. The objective of this review is to discuss the role of interventional pain procedures and evidence of their effectiveness in treatment of chronic LBP.

METHODS

This is a narrative review examining published studies on interventional procedures for LBP. The rationales, indications, technique, evidence, and complications for the interventional procedures are discussed.

RESULTS

Interventional pain procedures are used extensively in diagnosis and treatment of chronic pain. LBP is multifactorial, and while significant progress has been made in understanding its pathophysiology, this has not resulted in a proportional improvement of functional outcomes. For certain procedures, such as spinal cord stimulation, medical branch blocks and radiofrequency ablations, and epidural steroid injections for radiculopathy, safety, efficacy, and cost-effectiveness in treating LBP have been well studied. For others, such as interventions for discogenic pain, treatment successes have been modest at best.

CONCLUSIONS

Implementation of interventional pain procedures in the treatment framework of LBP has resulted in improvement of pain intensity in at least the short and medium terms, but equivocal results have been observed in functional improvement.

Histomorphologic and histomorphometric characteristics of zygapophyseal joint remodeling in ankylosing spondylitis

OBJECTIVE

To unravel the mechanisms that control bony ankylosis in ankylosing spondylitis (AS).

METHODS

Histomorphologic and histomorphometric analyses were performed on zygapophyseal joints obtained from 18 patients with AS, 9 patients with osteoarthritis (OA), and 10 cadaver donors without a rheumatic disease (controls). The proteoglycan content of the cartilage was determined by Safranin O staining and the chondrocyte apoptosis according to caspase 3 expression.

RESULTS

AS joints were categorized into 3 groups according to the morphology of the joint surfaces and joint space: group 1 were joints with an open joint space, group 2 were joints with cartilaginous fusion, and group 3 were joints with bony fusion of the joint surfaces. Progressive loss of the joint space from group 1 joints to group 3 joints suggests that this grouping corresponds to sequential stages of joint remodeling. Cartilage thickness and subchondral bone plate thickness declined from group 1 to group 3 (P < 0.01). Increased chondrocyte apoptosis rates were found in groups 1 and 2 (P < 0.05), while in group 3, a reduction in the proteoglycan content was found (P < 0.001). Bone marrow replacement and invasion of the subchondral bone plate by fibrous tissue was found predominantly in AS joints in group 2.

CONCLUSION

Cartilage degeneration, indicated by cartilage thinning, enhanced chondrocyte apoptosis, and proteoglycan loss, and subchondral bone thinning, promoted by invasion of the subchondral bone plate by a fibrous tissue originating from the bone marrow, are hallmarks of joint remodeling in AS.

Lumbar facet joint arthritis is associated with more coronal orientation of the facet joints at the upper lumbar spine

We retrospectively analyzed CT scans of 620 individuals, who presented to our traumatology department between 2008 and 2010. Facet joint (FJ) arthritis was present in 308 (49.7%) individuals with a mean grade of 1. It was seen in 27% of individuals ≤40 years and in 75% of individuals ≥41 years (P < 0.0001) as well as in 52% of females and 49% of males (P = 0.61). Mean FJ orientation was 30.4° at L2/3, 38.7° at L3/4, 47° at L4/5, and 47.3° at L5/S1. FJ arthritis was significantly associated with more coronal (increased degree) FJ orientation at L2/3 (P = 0.03) with a cutoff point at ≥32°. FJs were more coronally oriented (48.8°) in individuals ≤40 years and more sagittally oriented (45.6°) in individuals ≥41 years at L5/S1 (P = 0.01). Mean FJ asymmetry was 4.89° at L2/3, 6.01° at L3/4, 6.67° at L4/5, and 7.27° at L5/S1, without a significant difference for FJ arthritis. FJ arthritis is common, increases with age, and affects both genders equally. More coronally oriented FJs (≥32°) in the upper lumbar spine may be an individual risk factor for development of FJ arthritis.

Presence and extent of severe facet joint osteoarthritis are associated with back pain in older adults

OBJECTIVE

To determine whether the presence and extent of severe lumbar facet joint osteoarthritis (OA) are associated with back pain in older adults, accounting for disc height narrowing and other covariates.

DESIGN

Two hundred and fifty-two older adults from the Framingham Offspring Cohort (mean age 67 years) were studied. Participants received standardized computed tomography (CT) assessments of lumbar facet joint OA and disc height narrowing at the L2-S1 interspaces using four-grade semi-quantitative scales. Severe facet joint OA was defined according to the presence and/or degree of joint space narrowing, osteophytosis, articular process hypertrophy, articular erosions, subchondral cysts, and intraarticular vacuum phenomenon. Severe disc height narrowing was defined as marked narrowing with endplates almost in contact. Back pain was defined as participant report of pain on most days or all days in the past 12 months. We used multivariable logistic regression to examine associations between severe facet joint OA and back pain, adjusting for key covariates including disc height narrowing, sociodemographics, anthropometrics, and health factors.

RESULTS

Severe facet joint OA was more common in participants with back pain than those without (63.2% vs 46.7%; P = 0.03). In multivariable analyses, presence of any severe facet joint OA remained significantly associated with back pain (odds ratio (OR) 2.15 [95% confidence interval (CI) 1.13-4.08]). Each additional joint with severe OA conferred greater odds of back pain [OR per joint 1.20 (95% CI 1.02-1.41)].

CONCLUSIONS

The presence and extent of severe facet joint OA on CT imaging are associated with back pain in community-based older adults, independent of sociodemographics, health factors, and disc height narrowing.

The use of glucosamine for chronic low back pain: a systematic review of randomised control trials

OBJECTIVES

To ascertain whether the use of oral glucosamine influences symptoms or functional outcomes in patients with chronic low back pain (LBP) thought to be related to spinal osteoarthritis (OA).

DESIGN

Systematic review of randomised control trials. Searches were performed up to March 2011 on Medline, AMED, CINHAL, Cochrane and EMBASE with subsequent reference screening of retrieved studies. In addition, the grey literature was searched via opensigle. Included studies were required to incorporate at least one of the Cochrane Back Pain Review Group's outcome measures as part of their design. Trials with participants over 18 years with a minimum of 12 weeks of back pain, in combination with radiographic changes of OA in the spine, were included. Studies were rated for risk-of-bias and graded for quality.

RESULTS

148 studies were identified after screening and meeting eligibility requirements, and three randomised controlled trials (n=309) were included in the quantitative synthesis. The review found that there was low quality but generally no evidence of an effect from glucosamine on function, with no change in the Roland-Morris Disability Questionnaire score in all studies. Conflicting evidence was demonstrated with pain scores with two studies showing no difference and one study with a high risk-of-bias showing both a statistically and clinically significant improvement from taking glucosamine.

CONCLUSIONS

On the basis of the current research, any clinical benefit of oral glucosamine for patients with chronic LBP and radiographic changes of spinal OA can neither be demonstrated nor excluded based on insufficient data and the low quality of existing studies.

Osteoarthritis of the spine: the facet joints

Osteoarthritis (OA) of the spine involves the facet joints, which are located in the posterior aspect of the vertebral column and, in humans, are the only true synovial joints between adjacent spinal levels. Facet joint osteoarthritis (FJ OA) is widely prevalent in older adults, and is thought to be a common cause of back and neck pain. The prevalence of facet-mediated pain in clinical populations increases with increasing age, suggesting that FJ OA might have a particularly important role in older adults with spinal pain. Nevertheless, to date FJ OA has received far less study than other important OA phenotypes such as knee OA, and other features of spine pathoanatomy such as degenerative disc disease. This Review presents the current state of knowledge of FJ OA, including relevant anatomy, biomechanics, epidemiology, and clinical manifestations. We present the view that the modern concept of FJ OA is consonant with the concept of OA as a failure of the whole joint, and not simply of facet joint cartilage.

Osteoarthritis of the spine: the facet joints

Osteoarthritis (OA) of the spine involves the facet joints, which are located in the posterior aspect of the vertebral column and, in humans, are the only true synovial joints between adjacent spinal levels. Facet joint osteoarthritis (FJ OA) is widely prevalent in older adults, and is thought to be a common cause of back and neck pain. The prevalence of facet-mediated pain in clinical populations increases with increasing age, suggesting that FJ OA might have a particularly important role in older adults with spinal pain. Nevertheless, to date FJ OA has received far less study than other important OA phenotypes such as knee OA, and other features of spine pathoanatomy such as degenerative disc disease. This Review presents the current state of knowledge of FJ OA, including relevant anatomy, biomechanics, epidemiology, and clinical manifestations. We present the view that the modern concept of FJ OA is consonant with the concept of OA as a failure of the whole joint, and not simply of facet joint cartilage.

In vivo topographic analysis of lumbar facet joint space width distribution in healthy and symptomatic subjects

STUDY DESIGN

In vivo 3-dimensional facet joint space width measurement.

OBJECTIVE

To determine lumbar facet joint space width within clinically relevant topographical zones in vivo and its correlations with age, level, and presence of lower back pain symptoms.

SUMMARY OF BACKGROUND DATA

Facet joint gap narrowing, articular cartilage thinning, and subarticular cortical bone hypertrophy are frequently observed age-related changes. Facet joint space width is a well-defined parameter to evaluate osteoarthritis. To the best of our knowledge, there is no other study that quantifies 3-dimensional facet joint space width distribution in vivo.

METHODS

Three-dimensional measurement to quantify facet joint space width distribution based on 5 clinically relevant topographic zones in a cohort of healthy and symptomatic volunteers with low back pain, using subject-based 3-dimensional computed tomographic models with respect to spinal level, subject age, sex, and presence/absence of lower back pain.

RESULTS

Facet joint space width (mean ± SD) was 1.93 ± 0.51 mm for the central zone, 1.75 ± 0.48 mm for the superior zone, 1.63 ± 0.49 mm for the inferior zone, 1.48 ± 0.44 mm for the medial zone, and 1.65 ± 0.48 mm for the lateral zone, respectively. There were no significant differences between right and left facet joints. Male patients showed larger space width than female patients. Overall, space width of symptomatic subjects was significantly narrower than that of the asymptomatic group. Facet joints in the peripheral zones were narrower than in the central zone. Age-group comparisons showed that local narrowing occurring as early as in the third decade at the inferior zone of L5-S1, with all the remaining zones implicated after the fourth decade.

CONCLUSION

This in vivo study shows variations in facet joint space width narrowing with spinal level and region within the facet joint and in vivo evidence of localized, age-influenced facet cartilage thinning. Techniques developed in this study may be applied in the detection of early osteoarthritis-related changes in the facet joints.