Facet Joint Osteoarthritis Research Articles

Lumbar Facet Resurfacing: First Experience With the FENIX Implant.

This is a feasibility study to confirm the design, patient population, and the surgical technique for FENIX implants. This study evaluated the safety and the clinical and radiologic performance of bilaterally implanted FENIX facet resurfacing device. Facet joint osteoarthritis is responsible for up to 30% of chronic low back pain. Arthroplasty is a surgical treatment option that aims to relieve pain while maintaining or restoring motion. A total of 8 consecutive patients with proven single segmental bilateral lumbar facet joint osteoarthritis as unique pain generator received a bilateral implantation of the FENIX device. Correct device placement and mobility preservation were assessed on x-ray at 6 weeks and at 6, 12, and 24 months after implantation. Magnetic resonance imaging at 12 and 24 months after surgery assessed the bony ingrowth and computed tomography-single photon emision computed tomography was repeated at 6 months to assess evolution of the preoperative inflamed facet joints. The Oswestry disability index, pain visual analogue scale, and the need for analgesic medication were the parameters used for clinical assessment. At 24 months after surgery, 7 of the 8 patients were found to have all implants in place and all assessed parameters were found to be normal. Patients experienced significant pain relief and functionality improvement. Mobility was maintained and no Modic changes were noted, either at the index or at the adjacent levels. No "hot" lesions at the implanted levels were observed on computed tomography-single photon emision computed tomography. One of the 48 (2%) implants was found to be dislocated at 6 months follow-up. The FENIX facet resurfacing technique might be considered in the future as a surgical treatment of well-selected patients suffering from chronic low back pain because of facet joint osteoarthritis. A modification of the superior implant should provide an initial firm fixation preventing implant dislocation.

Multiple Psychiatric Manifestations in an Iraqi Patient with Facet Joint Osteoarthritis: A Case Report

Introduction: Generalized anxiety disorder (GAD) is a common psychiatric condition, which is more common in females. The associated individual-societal burden of GAD is substantial. GAD can be further complicated by panic disorder (PD), a disabling condition, which is often accompanied by other psychiatric and medical conditions, including GAD. In this case, PD was accompanied by facet joint osteoarthritis (FJOA) of the lumbar spine. FJOA is a functional failure of synovial facet joints due to variable degrees of loss of the synovial cartilage. This case report aimed to present a unique interaction of psychiatric manifestations and a physical disability, both of which interacted and augmented each other substantially. Case Presentation: This was a challenging case of a young 32-year old male patient from Baghdad,Iraq. His psychiatric medical condition lasted for about three years (2012 - 2015). Almost all the patient’s problems originated from an imbalanced relationship with an older female colleague. This relationship was the source of psychological disturbance that gradually affected the patient’s routine life, work and professionalism, social interactions, and family relationships. The patient’s psychological distress was centered around the female’s past sexual life, including her past marital life, and her pre-marital experience with multiple sexual partners. The patient became gradually convinced that the female was in desperate need of his persistent support to overcome her recent divorce, which eventually exhausted the patient. Later, he developed a parallel medical condition, facet joints’ degeneration of the lumbar spine. His psychiatric condition manifested as signs and symptoms of generalized anxiety, relapsing depression, and frequent panic attacks. Conclusions: This unique case of persistent lumbar back pain became a two-faceted agent, interfering with patient’s daily physically activity, causing significant emotional distress, depression, anxiety, and frequent panic attacks. His lumbar spine problem persisted for approximately a year, but it was improved dramatically in late 2015; since then no residual effects interfered with his psychological improvement, apart from the sporadic and negligible flashbacks of his emotionally traumatic experience. In this peculiar case, the physical illness of the patient played a key role in augmenting, impending, and delaying the full psychological recovery.

Facet orientation and tropism: Associations with asymmetric lumbar paraspinal and psoas muscle parameters in patients with chronic low back pain.

Many studies have explored the relationship between facet tropism and facet joint osteoarthritis, disc degeneration and degenerative spondylolisthesis. However, the associations between facet orientation and tropism, and paraspinal muscles have not been studied. To analyze the associations between facet orientation and tropism, and parameters of paraspinal muscles in patients with chronic low back pain. Ninety-five patients with chronic low back pain were consecutively enrolled. Their facet joint angles were measured on computed tomography (CT) while gross cross-sectional area (GCSA), functional cross-sectional area (FCSA) and T2 signal intensity of lumbar paraspinal and psoas muscle were evaluated on magnetic resonance imaging (MRI). The GCSA and FCSA were significantly smaller for multifidus muscle (P< 0.001), but significantly larger for erector spinae and psoas muscles (P< 0.001), in coronally-orientated group than those in sagittally-orientated group. The differences of bilateral GCSA and FCSA of multifidus muscle were significantly larger in facet tropism group than those in no facet tropism group (P= 0.009 and P= 0.019). Muscular asymmetries may develop in the lumbar region of the spine, which are associated with facet asymmetry in patients with chronic low back pain. Longitudinal studies are needed to understand the causal relationship between facet orientation and tropism and muscular asymmetry in future.

Does the type of sagittal spinal shape influence the clinical results of lumbar disc arthroplasty?

IntroductionIt has been suggested that the indication for lumbar total disc replacement (LTDR) takes into account the local parameters, such as the type of disc disease demonstrated on MRI and the presence or absence of facet joint osteoarthritis. The type of preoperative sagittal curvature could also be taken into account. This study reports the clinical results of LTDRs depending on the type of sagittal spinal alignment. Material and methodsEighty patients were included in this prospective study, with a mean age of 41.7years (range, 27–56years). The clinical analysis took into account the lumbar VAS, the Oswestry Disability Index (ODI), and the preoperative frequency of painkiller use, at 1year and at the last follow-up. The satisfaction index, return to work, and willingness to undergo the same treatment were also collected. The radiological study included the analysis of lumbar-pelvic parameters to distribute the patients according to the Roussouly classification. ResultsThe mean follow-up was 59.1months (range, 14–96months). The type 1 group included four cases. Reduction of the VAS, the ODI score, and the frequency of painkiller use at the last follow-up were significant in type 2 and 3 patients, and non-significant for type 4. Eighty-five percent of type 2 patients and 87.5% of type 3 patients were satisfied or very satisfied with the surgery versus only 68% of the type 4 patients. In addition, 63% of the type 4 patients declared they would be willing to undergo the same treatment again versus 85% of the type 2 patients and 82.5% of the type 3 patients. It should also be noted that 67% of the patients in this series returned to work. Discussion and conclusionThis study underscores the influence of the type of sagittal curvature on the clinical results of LTDR, with type 4 patients showing inferior clinical results because of a higher rate of residual lower back pain. The indication in LTDR should be reconsidered for discogenic lower back pain in type 4 patients.

Heritability of Thoracic Spine Curvature and Genetic Correlations With Other Spine Traits: The Framingham Study.

Hyperkyphosis is a common spinal disorder in older adults, characterized by excessive forward curvature of the thoracic spine and adverse health outcomes. The etiology of hyperkyphosis has not been firmly established, but may be related to changes that occur with aging in the vertebrae, discs, joints, and muscles, which function as a unit to support the spine. Determining the contribution of genetics to thoracic spine curvature and the degree of genetic sharing among co-occurring measures of spine health may provide insight into the etiology of hyperkyphosis. The purpose of our study was to estimate heritability of thoracic spine curvature using T4 -T12 kyphosis (Cobb) angle and genetic correlations between thoracic spine curvature and vertebral fracture, intervertebral disc height narrowing, facet joint osteoarthritis (OA), lumbar spine volumetric bone mineral density (vBMD), and paraspinal muscle area and density, which were all assessed from computed tomography (CT) images. Participants included 2063 women and men in the second and third generation offspring of the original cohort of the Framingham Study. Heritability of kyphosis angle, adjusted for age, sex, and weight, was 54% (95% confidence interval [CI], 43% to 64%). We found moderate genetic correlations between kyphosis angle and paraspinal muscle area (ρˆG , -0.46; 95% CI, -0.67 to -0.26), vertebral fracture (ρˆG , 0.39; 95% CI, 0.18 to 0.61), vBMD (ρˆG , -0.23; 95% CI, -0.41 to -0.04), and paraspinal muscle density (ρˆG , -0.22; 95% CI, -0.48 to 0.03). Genetic correlations between kyphosis angle and disc height narrowing (ρˆG , 0.17; 95% CI, -0.05 to 0.38) and facet joint OA (ρˆG , 0.05; 95% CI, -0.15 to 0.24) were low. Thoracic spine curvature may be heritable and share genetic factors with other age-related spine traits including trunk muscle size, vertebral fracture, and bone mineral density. © 2016 American Society for Bone and Mineral Research.

Menopause as a potential cause for higher prevalence of low back pain in women than in age-matched men

SummaryFemale sex hormones play an important role in the aetiology and pathophysiology of a variety of musculoskeletal degenerative diseases. Postmenopausal women show accelerated disc degeneration due to relative oestrogen deficiency, resulting in narrower intervertebral disc space in women than age-matched men, increased prevalence of spondylolisthesis, and increased prevalence of facet joint osteoarthritis. Postmenopausal women also show higher osteoporosis related spine fracture rate, particularly at the thoracic–lumbar junction site. I propose the concept that low back pain (LBP) is more prevalent in postmenopausal women than age-matched men and is associated with the physiological changes caused by the relatively lower level of sex hormones after menopause in women. Considering hormone replacement treatment (HRT)'s consistent efficacy reported with menopause-associated osteoarthritis, an in-depth understanding of the role of the gonadal hormones in LBP modulation warrants further study. HRT initiated at early postmenopausal phase may be protective for recurring LBP. If this is the case, further cost–benefit analysis should be performed for optimal HRT regimen in cases of women with high risk of recurring severe LBP.

Characterization of subchondral bone histopathology of facet joint osteoarthritis in lumbar spinal stenosis.

Facet joint osteoarthritis may be a cause of low back pain in degenerative spine diseases including lumbar spinal stenosis. Subchondral bone is regarded as a potential therapeutic target for osteoarthritis treatment. The goal of this study was to characterize subchondral bone histopathology in osteoarthritic facet joints from lumbar spinal stenosis patients. Fifteen patients with degenerative spinal stenosis scheduled for transforaminal lumbar interbody fusion surgery were recruited for this study. Osteoarthritis severity was graded on T1- and T2-weighted MRI images using Weishaupt scoring system. Dissected osteoarthritic facet joints were subjected to histological and immunohistochemistry analyses to study relative abundance of osteoblast, osteoclasts, and macrophages using van Gieson's, tartrate-resistant acid phosphatase and CD68-antibody staining, respectively. Presence of nerve fibers was evaluated by PGP9.5-antibody staining. Differential bone histopathology, independent from radiological osteoarthritis grade, was observed in facet joints. Extensive de novo bone formation was found in subchondral bone tissues of eight of fifteen specimens. Regions of bone formation showed high abundance of blood vessels and CD68-positive macrophages, but were devoid of multinucleated osteoclasts. Additional pathological changes in subchondral marrow spaces, including inflammatory infiltration and enhanced osteoclast activity, were characterized by macrophage-rich tissues. PGP9.5-positive nerve fibers were detected near arterioles, but not in regions displaying bone pathology. Individual histopathological parameters did not associate with clinical features or radiological osteoarthritis severity. Subchondral bone histopathology of facet joint osteoarthritis in lumbar spinal stenosis is characterized by marrow infiltration by macrophage-rich tissues and enhanced de novo bone formation. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:1475-1480, 2016.

Lumbar Spinal Segmental Hypomobility Induced Osteoarthritis is Associated with Early Regression of Facet Joint Synovial Folds

Spinal osteoarthritis of the lumbar facet joints is one of the most prevalent and burdensome causes of low back pain (LBP). This condition involves numerous tissues that can directly or indirectly induce pain (e.g., cartilage, bone, synovium, and capsule). Specifically, pathophysiological and morphological changes to the synovium, a key tissue that maintains the health of the joint articular surface, are reported to contribute to the onset and progression of OA. We have previously reported a novel rat model that uses external spinal linkage to cause lumbar spinal hypomobility and induce OA in lower lumbar facet joints (L4/5 and L5/6). This model may replicate the progression of spinal OA in humans and allow mechanistic studies of facet joint OA induced pain. We have shown that this hypomobility is associated with significant bilateral OA changes including synovial fold (SF) regression from within the joint space by 4‐weeks post linkage. The onset of this SF change is unknown. Here we examined if lower lumbar spinal segmental hypomobility in rats is associated with early onset of SF regression from the joint space in the bilateral L4/5 and L5/6 facet joints. We hypothesized that significant SF regression occurs by 1 week following spinal linkage. Analysis was performed using a histological approach based upon our previously reported methods to test our hypothesis in linked (hypomobile) and time matched control rats at 1, 2, and 4 weeks post linkage. The number of facet joint quadrants with SFs was determined using brightfield microscopy to observe formalin fixed, decalcified, paraffin embedded, Ehrlich's hematoxylin and light green stained 45 μm thick sections of the facet joints. The mean number of quadrants containing SFs was calculated for each group. This approach demonstrated acceptable inter‐ and intra‐rater reliability (κ= 0.82 and κ= 0.77). Statistical analysis was performed using a one way ANOVA with Tukey's multiple comparisons. Significance was defined as p &lt;0.05. When compared with time matched control animals (n=4), linked rats demonstrated significant reductions of the SF along the joint surface at 2 and 4 weeks of hypomobility (n=4). No significant differences were found between control groups or at week 1 following linkage. As the synovium can contribute to the development of OA, it is possible that regression of SF in the facet joint by 2 weeks post linkage may reflect pathophysiological changes that contribute to the induction of articular cartilage and subchondral bone degeneration. Further work is required to support these findings including morphometric and mechanistic approaches to determine the functional role of the synovium in hypomobility induced OA and pain. Collectively, these findings support that lumbar spine segmental hypomobility leads to an early onset of SF regression.

Histopathological Features of Facet Osteoarthritis in Patients with Lumbar Spinal Stenosis

Introduction Lumbar spinal stenosis (LSS) is a degenerative, age-related narrowing of the lower spinal canal that causes pressure on the nerves, leading to pain and reduced mobility. Hypertrophy of ligament flava and facet joints combined with disc protrusions are a causative for LSS. Osteoarthritic changes to the facet joint, including joint space narrowing, subchondral cysts and osteophyte formation are commonly detected using magnetic resonance imaging (MRI) and computed tomography (CT) scanning. However, the pathomechanisms of facet joint osteoarthritis (OA) at a cellular and molecular level are poorly understood and have been scarcely studied. In this study we sought to investigate the histological features and to uncover cellular pathomechanisms of facet joint OA. Material and Methods Fifteen patients undergoing surgical decompression due to degenerative LSS were included in this study (9 female/6 male, median age 66, range 49–85). Routine preoperative X-ray and MRI scanning of the lumbar spine was performed in all subjects. Severity of facet joint OA was assessed in MRI images using the Weishaupt grading system for the lumbar spine. The medial portion of facet joints was collected during surgical decompression of the spinal canal and processed for tissue histology. Tissue morphology was evaluated using haematoxylin and eosin (HE), Safranin-O and van Gieson's stains. The presence of macrophages, blood vessels and nerve fibers was investigated using immunohistological staining for their respective markers CD68, CD34 and PGP9.5. Functional osteoclasts were visualized using tartrate-resistant acid phosphatase (TRAP) staining. Subchondral bone area fraction (B.Ar/T.Ar) was determined using the ImageJ-plugin BoneJ. Results OA was evident in MRI images characterized by joint space narrowing, bone edema and cysts and hypertrophy of articular processes. The severe OA phenotype in facet joints from LSS patients was confirmed at a histological level by complete loss of proteoglycan staining, CD34+ vessel penetration, and fissuring of cartilage tissue. Subchondral B.Ar/T.Ar ranged between 0.6 and 0.8. In all samples, subchondral marrow spaces contained CD34+ blood vessels and CD68+ mononuclear macrophages. CD68+ multinucleated osteoclasts were detected in resorption pits at the bone surface in 80 percent of the patients. Functionality of osteoclasts was confirmed by positive staining of multinucleated bone cells for TRAP in serial sections. Osteoblast activity was demonstrated in 60 percent of the patients and predominantly characterized by large areas of intramembranous bone formation near the osteochondral junction. Formation of an osteoclast-rich pannus-like tissue was seen in one sample. Innervation of subchondral marrow spaces by PGP9.5-positive nerve fibers was scarce and exclusively found in the vicinity of arterioles. Conclusion Facet joints in LSS patients display radiological and histopathological features of OA. Two major OA phenotypes can be distinguished based upon cellular pathomechanisms in subchondral bone tissue: 1) osteoblast-rich intramembranous bone formation and 2) osteoclast/macrophage rich remodeling. Osteoimmunological mechanisms, specifically the interaction of CD68+ macrophages with bone-resident cells, play a – previously unknown – role in regulating subchondral bone sclerosis in progressive osteoarthritis. Targeting osteoimmunology might hold potential as a disease-modifying treatment for osteoarthritis.

Characterization of age- and gender-specific trabecular bone structural parameters and mesenchymal stromal cells of osteoarthritic facet joints in lumbar spinal stenosis

Purpose: Facet joint osteoarthritis may be a cause of low back pain in degenerative spine diseases such as lumbar spinal stenosis. While increased bone remodeling is a clinical hallmark of osteoarthritis, the trabecular bone structural parameters of osteoarthritic lumbar facet joints have not been characterized thus far. Interestingly, an age- and gender-specific decrease of trabecular number, thickness and volume fraction has been previously described for lumbar 4/5 facet joints of healthy individuals. Here, we sought to characterize trabecular bone structural parameters and subchondral bone-resident mesenchymal stromal cells (MSC) of osteoarthritic facet joints and compare these with regard to age, gender and healthy controls. Methods: Twenty-one patients scheduled for decompression and stabilization surgery for degenerative spinal stenosis were recruited for this study. Facet joint specimens were harvested during surgery and either fixed in formalin for microcomputed tomography (n = 15) or isolation of MSC by collagenase digestion (n = 6). MicroCT was performed spatial resolution of 20.5 μm. Bone volume fraction (BV/TV), trabecular thickness (Tb.Th), trabecular separation (Tb.Sp) and trabecular number (Tb.N) were evaluated using CT Analyser. Trabecular bone structural parameters of healthy subjects were taken from Wilke and co-workers (J. Anat. 2012). Statistical analysis of differences between gender and age groups (40–60 and 60–80 years) were performed using two-way analysis of variance (ANOVA). Early passage MSC were subjected to adipogenic and osteogenic differentiation for three weeks and evaluated using alkaline phosphatase assay, Alizarin red and Oil red O staining and RT-PCR. Results: Trabecular BV/TV was 0.36 ± 0.14 and 0.35 ± 0.17 for osteoarthritic lumbar facet joints of male and female individuals, respectively. Contrastingly, mean BV/TV in age-matched healthy controls was 0.32 (male) and 0.25 (female). Tb.Th was in the same range for both genders and age-groups (overall mean 0.20 ± 0.07 mm) and did not differ from healthy controls. The overall Tb.Sp averaged 0.52 ± 0.16 mm, which was lower than averages observed for age-matched healthy females (0.60) and males (0.71). Accordingly, Tb.N in osteoarthritic facet joints of male (1.9 ± 1.3/mm) and female (1.7 ± 0.8/mm) patients with lumbar spinal stenosis was higher than reported for healthy controls (1.5–1.0/mm). Statistical analysis did not reveal any age- or gender-specific differences in trabecular bone structural parameters of osteoarthritic lumbar facet joints. Facet joint MSC showed a strongly upregulated alkaline phosphatase activity upon adipogenic (8.1-fold) and osteogenic (4.6-fold) differentiation. Only a low number of lipid vacuoles were detected after adipogenesis. Alizarin red staining revealed varying degrees of in vitro matrix mineralization in MSC, which ranged from blunted to strong mineralization. Conclusions: Subchondral trabecular bone remodeling in lumbar facet joint osteoarthritis is characterized by an increase in bone volume fraction due to a higher trabecular number, but not an increase of trabecular thickness. MSC from osteoarthritic facet joints display impaired adipogenesis and abnormal mineralization during osteogenesis. These data provide a strong rationale for targeting increased bone remodeling in lumbar facet joint osteoarthritis.

Analysis of the Relationship between Ligamentum Flavum Thickening and Lumbar Segmental Instability, Disc Degeneration, and Facet Joint Osteoarthritis in Lumbar Spinal Stenosis.

Study DesignCross-sectional study.PurposeTo investigate the relationship between ligamentum flavum (LF) thickening and lumbar segmental instability and disc degeneration and facet joint osteoarthritis.Overview of LiteraturePosterior spinal structures, including LF thickness, play a major role in lumbar spinal canal stenosis pathogenesis. The cause of LF thickening is multifactorial and includes activity level, age, and mechanical stress. LF thickening pathogenesis is unknown.MethodsWe examined 419 patients who underwent computed tomography (CT) myelography and magnetic resonance imaging after complaints of clinical symptoms. To investigate LF hypertrophy, 57 patients whose lumbar vertebra had normal disc heights at L4–5 were selected to exclude LF buckling as a hypertrophy component. LF thickness, disc space widening angulation in flexion, segmental angulation, presence of a vacuum phenomenon, and lumbar lordosis at T12–S1 were investigated. Disc and facet degeneration were also evaluated. Facet joint orientation was measured via an axial CT scan.ResultsThe mean LF thickness in all patients was 4.4±1.0 mm at L4–5. There was a significant correlation between LF thickness and disc degeneration; LF thickness significantly increased with severe disc degeneration and facet joint osteoarthritis. There was a tendency toward increased LF thickness in more sagittalized facet joints than in coronalized facet joints. Logistic regression analysis showed that LF thickening was influenced by segmental angulation and facet joint osteoarthritis. Patient age was associated with LF thickening.ConclusionsLF hypertrophy development was associated with segmental instability and severe disc degeneration, severe facet joint osteoarthritis, and a sagittalized facet joint orientation.

The Morphology of Degenerated Lumbar Disc May Indicate Segmental Instability: Technical Note

Lumbar intervertebral disc degeneration is related to progressive alterations in the disc tissue composition and morphology, such as disc dehydration, decreased disc height, osteophyte formation and endplate calcification. These changes are related to aging and usually precede facet joint osteoarthritis. The grade of disc degeneration is related to segmental instability. The morphology of lumbar intervertebral disc degeneration may be potential cause for instability. This work aimed to describe the potential instability associated with the conical degenerated lumbar disc which is wide anteriorly-and narrow posteriorly in comparison to adjacent disc level. Radiological studies and intraoperative notice include, degenerative spondylolithesis, fracture pars, spondylolithsis, facet opening with abnormal ballooned and lose facet joint capsule, and loose lamina. This technical note highlights the importance of morphology of the degenerated lumbar disc which assume conical shape on Sagittal MRI which may indicate instability and required careful investigation before surgery

The Relationship Between Osteoarthritis of the Lumbar Facet Joints and Lumbosacropelvic Morphology.

Cross-sectional study. To investigate the relation between lumbosacropelvic morphology and the presence and degree of facet joint degeneration. Osteoarthritis of the facet joints is one of the most common degenerative changes in the spine. It is considered to be formed secondary to repetitive stress or trauma and spinal deformity with secondary overload. The cause(s) of facet joints osteoarthritis, however, have not been clearly identified. Abdominal computed tomography (CT) images of 723 patients which were taken between the years 2010 and 2014 were evaluated retrospectively. Patients with prior lumbar spinal surgery, serious congenital anomalies on CT, incomplete or complete lumbosacral transition, severe scoliosis, were excluded from the study. To eliminate the age- and sex-related differences in spinopelvic morphology, a study group was formed of the remaining subjects by including patients from a specific age group (30-35 yr) and same sex (females). For each patient the presence and grade of facet joint degeneration was investigated. In addition, pelvic incidence (PI), sacral slope and the angles of L1-L5 lumbar lordosis, sacral table, L5 vertebra posterior, and sacral kyphosis were measured for each patient. Sacral slope, sacral kyphosis, and L1-L5 lumbar lordosis angle were significantly higher in patients with osteoarthritic compared with normal subjects (P = 0.015, P = 0.018, P = 0.016). L5 vertebra posterior and sacral table angle were found to be significantly lower in patients with osteoarthritic than in normal subjects (P = 0.019, P = 0.007). The degree of facet joint degeneration was noticed to increase parallel to the decrease in the sacral table angle and L5 vertebra posterior angle, and to the increase in the L1-L5 lumbar lordosis, PI, and sacral slope. A close relation exists between the presence and degree of degeneration in the facet joint and lumbosacral pelvic morphology. Prevalence and degree of the degeneration in facet joint increases as the angle of sacral slope, L1-L5 lumbar lordosis, and PI increases or the angle of sacral table and L5 vertebra posterior decreases. 4.

Development of an Experimental Animal Model for Lower Back Pain by Percutaneous Injury-Induced Lumbar Facet Joint Osteoarthritis.

We report generation and characterization of pain-related behavior in a minimally invasive facet joint degeneration (FJD) animal model in rats. FJD was produced by a non-open percutaneous puncture-induced injury on the right lumbar FJs at three consecutive levels. Pressure hyperalgesia in the lower back was assessed by measuring the vocalization response to pressure from a force transducer. After hyperalgesia was established, pathological changes in lumbar FJs and alterations of intervertebral foramen size were assessed by histological and imaging analyses. To investigate treatment options for lumber FJ osteoarthritis-induced pain, animals with established hyperalgesia were administered with analgesic drugs, such as morphine, a selective COX-2 inhibitor, a non-steroidal anti-inflammatory drug (NSAID) (ketorolac), or pregabalin. Effects were assessed by behavioral pain responses. One week after percutaneous puncture-induced injury of the lumbar FJs, ipsilateral primary pressure hyperalgesia developed and was maintained for at least 12 weeks without foraminal stenosis. Animals showed decreased spontaneous activity, but no secondary hyperalgesia in the hind paws. Histopathological and microfocus X-ray computed tomography analyses demonstrated that the percutaneous puncture injury resulted in osteoarthritis-like structural changes in the FJs cartilage and subchondral bone. Pressure hyperalgesia was completely reversed by morphine. The administration of celecoxib produced moderate pain reduction with no statistical significance while the administration of ketorolac and pregabalin produced no analgesic effect on FJ osteoarthritis-induced back pain. Our animal model of non-open percutanous puncture-induced injury of the lumbar FJs in rats shows similar characteristics of low back pain produced by human facet arthropathy.

Does evaluator experience have an impact on the diagnosis of lumbar spine instability in dynamic MRI? Interobserver agreement study.

We aimed to evaluate interobserver agreement in the definition of spine instability among spine neuroradiologists with or without experience in dynamic magnetic resonance imaging (MRI). Two expert neuroradiologists and two residents retrospectively evaluated the pre-operative dynamic MRI examinations of patients with vertebral instability. Segmental motion, defined as excessive (more than 3 mm) translational motion from supine to upright, was investigated in 103 subjects (309 segments) using kinetic MRI. Radiographic parameters which can help indicate segmental instability include disc degeneration, facet joint osteoarthritis, and ligament flavum hypertrophy. These three radiographic parameters were simultaneously evaluated, and the combinations corresponding to significant segmental instability at each level were determined. The agreement among the neuroradiologists was calculated using the kappa coefficient. All patients had neurosurgical intervention to stabilize the spine. Agreement was high among experienced and non-experienced neuroradiologists. Agreement was nearly perfect for spinal location of spinal instability. This study demonstrates that the experience of the evaluator has a low impact on the assessment of spinal instability if correct classification is used. The interobserver agreement confirms the usefulness and safety of kinetic MRI in the correct diagnosis of spinal instability even by less experienced evaluators.

Indian Hedgehog signaling pathway members are associated with magnetic resonance imaging manifestations and pathological scores in lumbar facet joint osteoarthritis.

Indian Hedgehog (HH) has been shown to be involved in osteoarthritis (OA) in articular joints, where there is evidence that Indian HH blockade could ameliorate OA. It seems to play a prominent role in development of the intervertebral disc (IVD) and in postnatal maintenance. There is little work on IHH in the IVD. Hence the aim of the current study was to investigate the role of Indian Hedgehog in the pathology of facet joint (FJ) OA. 24 patients diagnosed with lumbar intervertebral disk herniation or degenerative spinal stenosis were included. Preoperative magnetic resonance imaging (MRI) and Osteoarthritis Research Society International (OARSI) histopathology grading system was correlated to the mRNA levels of GLI1, PTCH1, and HHIP in the FJs. The Weishaupt grading and OARSI scores showed high positive correlation (r = 0.894) (P < 0.01). MRI Weishaupt grades showed positive correlation with GLI1 (r = 0.491), PTCH1 (r = 0.444), and HHIP (r = 0.654) mRNA levels (P < 0.05 in each case). OARSI scores were also positively correlated with GLI1 (r = 0. 646), PTCH1 (r = 0. 518), and HHIP (r = 0.762) mRNA levels (P < 0.01 in each case). Cumulatively our findings indicate that Indian HH signaling is increased in OA and is perhaps a key component in OA pathogenesis and progression.

Establishment of a rat model of lumbar facet joint osteoarthritis using intraarticular injection of urinary plasminogen activator

Lumbar facet joint (LFJ) osteoarthritis (OA) is an important etiology of low back pain. Several animal models of LFJ OA have been established using intraarticular injection of various chemicals. This study aimed to establish a rat model of LFJ OA using urinary plasminogen activator (uPA). Sprague-Dawley rats were treated with intraarticular injection in the L5-L6 facet joints with uPA (OA group, n = 40) or normal saline (vehicle group, n = 40). Mechanical and thermal hyperalgesia in the ipsilateral hind paws were evaluated using von Frey hairs and a thermoalgesia instrument, respectively. Toluidine blue staining, hematoxylin-eosin staining, and immunohistochemical examination of the LFJ was performed. Treatment with uPA induced cartilage damage, synovitis, and proliferation of synovial cells in the fact joints. The OA group showed significantly higher hyperalgesia in the hind paws in comparison with the vehicle group and normal controls (P < 0.05). Expression of IL-1β, TNF-α, and iNOS in the LFJ cartilage in the OA group was significantly increased (P < 0.05). A rat model of LFJ OA was successfully established using intraarticular injection of uPA. This animal model is convenient and shows good resemblance to human OA pathology.

Physical activity and 6-year incidence of facet joint osteoarthritis in women and men: The Framingham study

Physical activity and 6-year incidence of facet joint osteoarthritis in women and men: The Framingham study

Mesenchymal stem cells in facet joint articular cartilage regeneration: Potential future perspectives

Facet joint osteoarthritis (facet syndrome) has been suggested to be one of the key pain generators in degenerative spinal conditions. Treatment options for facet syndrome include physical therapy, intra-articular injections, radiofrequency ablation, and surgery. Tissue engineering offers promise for the treatment of various musculoskeletal system disorders. Mesenchymal stem cells (MSCs) have multipotent characteristics and can differentiate into various tissues including articular cartilage. In this article, we analyze the literature and emphasize potential advantages and future perspectives in the treatment of articular facet joint cartilage defects using MSCs.

POSTERIOR ELEMENT MORPHOLOGY AND DEGENERATIVE LUMBAR SPONDYLOLISTHESIS

Study design: Retrospective radiographic studies on lumbar facet morphology, and facet and laminar inclination angles. Objectives: To investigate the effect of the facet morphology, facet and laminar inclination angles on development of the segmental instability and spondylolisthesis. Summary of background data: Many previous papers related with the facet shape on pathogenesis of the degenerative instability and spondylolisthesis were published. Most authors interpreted that the facet morphology in the pathogenesis of the spondylolisthesis was a factor secondary to facet joint osteoarthritis, and was not the primary one. None dealt the effect of facet shape and laminar inclination on slippage severity. Method: The subject materials were 50 patients (10 males and 40 females) with degenerative spondylolisthesis, treated between 1999 and 2013. Simple radiograms were utilized for assessment. Facet joints were classified by Tsunoda et al., based on its developmental shape and alignment on radiograms; X, M, and W types. Also the laminar inclination and facet inclination angles were measured. Results: Among 50 patients 45 had anterolisthesis with (forward flexion instability) and only five had retrolisthesis (extension instability). In 45 cases of anterolisthesis, there were 24 "X" types, 4 "M" types, and 17 "W" types, while in 5 cases of retrolisthesis there were 3 "X" and 2 "M" types. In 45 cases of anterolisthesis, 24 with "X" type facets had Myerding's grade I slip, and one had grade II slip; Among the 4 "M" types two had grade I slip and two had grade II slip, while among 17 "W" type, there were four grade I slip, 11 grade II slip, and two grade III slip. 13 out of the 16 anterolisthesis over grade II slip had "W" type facets. Vertebra with "W" type facets had average 130° laminar inclination angle and 122° facet inclination angles, while "X" and "M" type facets had less inclination of both angles. Conclusion: The defective facet morphology and laminar inclination angle of the lower lumbar spine can be the predisposing factor of development and slip progress of the degenerative anterolisthesis.