Articular Facet Joint Research Articles

Treatment of unilateral cervical facet fractures without evidence of dislocation or subluxation: a narrative review and proposed treatment algorithm.

Isolated cervical spine facet fractures are often overlooked. The primary imaging modality for diagnosing these injuries is a computed tomography scan. Treatment of unilateral cervical facet fractures without evidence of dislocation or subluxation remains controversial. The available evidence regarding treatment options for these fractures is of low quality. Risk factors associated with the failure of nonoperative treatment are: comminution of the articular mass or facet joint, acute radiculopathy, high body mass index, listhesis exceeding 2 mm, fragmental diastasis, acute disc injury, and bilateral fractures or fractures that adversely affect 40% of the intact lateral mass height or have an absolute height of 1 cm.

Facet joint disorders: from diagnosis to treatment.

One of the most common sources of spinal pain syndromes is the facet joints. Cervical, thoracic, and lumbar facet joint pain syndromes comprise 55%, 42%, and 31% of chronic spinal pain syndromes, respectively. Common facet joint disorders are degenerative disorders, such as osteoarthritis, hypertrophied superior articular process, and facet joint cysts; septic arthritis; systemic and metabolic disorders, such as ankylosing spondylitis or gout; and traumatic dislocations. The facet pain syndrome from osteoarthritis is suspected from a patient's history (referred pain pattern) and physical examination (tenderness). Other facet joint disorders may cause radicular pain if mass effect from a facet joint cyst, hypertrophied superior articular process, or tumors compress the dorsal root ganglion. However, a high degree of morphological change does not always provoke pain. The superiority of innervating nerve block or direct joint injection for diagnosis and treatment is still a controversy. Treatment includes facet joint injection in facet joint osteoarthritis or whiplash injury provoking referred pain or decompression in mass effect in cases of hypertrophied superior articular process or facet joint cyst eliciting radicular pain. In addition, septic arthritis is treated using a proper antibiotic, based on infected tissue or blood culture. This review describes the diagnosis and treatment of common facet joint disorders.

Diagnostic imaging of the equine cervical spine – Are radiographs enough?

Diagnostic imaging of the equine cervical spine – Are radiographs enough?

Case series of fluoroscopic findings and 3D reconstruction of human spinal MRIs of the space of Okada.

To better understand the unexpected spread of contrast medium observed by conventional fluoroscopic X-ray images during standard neuraxial techniques used in the treatment of pain. The support of 3D reconstruction of MRI images of structures within the lumbar spine was used to better understand the space of Okada. Lumbar facet joint and epidural corticosteroid injections in five patients under fluoroscopic guidance with loss of resistance to air or saline to identify the facet joints or epidural space. Next, in a retrospective study, the authors examined the retrodural space of Okada and the neighboring tissues with 3D reconstruction of spinal MRIs of seven patients without any demonstrable spinal pathology to better understand the characteristics of the space of Okada. Contrast medium spread to the ipsilateral and contralateral sides was observed in five patients. The contralateral spread was thought to be through the retrodural space of Okada, which is a potential space between the anterior surface of the vertebral lamina and the posterior surface of the ligamentum flavum. It facilitates communication between the contralateral articular facet joints of the spine. This study provides new evidence for the existence of the space of Okada where an unexpected contralateral spread occurred following facet joint and attempted epidural injection. The 3D reconstructions of MRIs may help us better understand the nature of the retrodural space of Okada and its clinical implications.

A study of cervical spine morphology variation influence in loading and range of motions using finite element analysis

The most commonly found disease in aged people which can be dangerous and which affects the condition of an individual’s life is disc degenerative disease. The shift in the anterior load-bearing column was caused by the disc height changes in posterior side which could have adverse effects on posterior column. The lack of symptoms at early stages makes the identification of disc degenerative disease difficult but once identified, the treatment actions should be taken at right time. Biomechanical literature gives a static morphology of the FE models of cervical spine. An upcoming tendency in the current day medical practice is the use of personalized medicines and the predicting capabilities of this trend gets affected by not taking into account morphology as a model parameter. Finite element analysis is used to find the effect of variations in morphology of spine, intervertebral disc height, slope of facet joint, process height of articular facet joint and segment size was parametrized. Finite element study was done on vertebral rotation variations and ligamental forces. Some of the most important morphological variations found in the anatomy were disc segmental size & height and body depth. The estimation of ROM and calculation of impact loads were found to be the key elements in the examination of degeneration of discs. Nonetheless there are risks involved in the extensive use of instruments for direct measurement of range of motion. Fem models of the lower cervical spine are derived from a CT scan with dissimilar elements and then quality of these models is evaluated with the help of mesh element-related metrics. The range of motion values are then compared with the literature studies and the model with good mesh standard are used for future examination process. The individual components of spine are subjected to different types of loading situations and the stresses developed on them need to studied. The results gained from the finite element model helps us to plot stresses of subjects obtained from the respective lifestyles can benefit surgeons to suggest treatment actions.

Influence of loading in cervical spine motion segment and stress distribution

The aim of this study is to create a three-dimensional model of a cervical spine motion segment and to confirm it by inspecting the model with similar FE method. Initially a model was created by extracting CT scan images and the mesh was generated. FEM models of the lower cervical spine are derived from a CT scan with dissimilar elements and then quality of these models is evaluated with the help of mesh element-related metrics. Different material properties were assigned for each part of the model and then the analysis was carried out. Finite element analysis is used to find the effect of variations in morphology of spine, intervertebral disc height, slope of facet joint, process height of articular facet joint and segment size was parameterized. Ligament forces and vertebral rotation variations was also done as part of the FE study. The individual components of spine are subjected to different types of loading situations and the stresses developed on them need to studied. Some of the most important morphological variations found in the anatomy were disc segmental size & stress developed in the superior and inferior endplates and also the stress developed in the disc were analysed. The results obtained were collated with some external references and after validation of the model; the model could be used for extended similar studies.

Effects of facet joint degeneration on stress alterations in cervical spine C5-C6: A finite element analysis.

It has been demonstrated that articular facet degeneration can cause local strain alterations and induce neck pain. This study aims to quantify the biomechanical effects of normal and degenerated C5-C6 articular facets, and evaluate the correlation of mechanical strain between healthy and degenerated spine. A 3-dimensional finite element (FE) model of the C5-C6 cervical spine was developed [Model 0 (M0)]. The asymmetric models of C5-C6 bilateral articular facet joint were established separately to mimic articular facet joint degeneration. The capsule ligament stiffness of C5-C6 unilateral facet joint was altered with minimum and maximum threshold to simulate capsule ligaments' lesion and calcification [Model 1 (M1) and Model 2 (M2), respectively]. Besides, the cervical C5-C6 unilateral articular facet joint direction was changed by 5° and 10° forward to imitate the moderate joint hyperplasia and severe osteophyte (Model 3 and Model 4 respectively). M1 increased the rotation range of ipsilateral side (left), while M2 reduced, and both had limited effect on the contralateral side (right). The angle increased in Model 3 (M3) (61°) and Model 4 (M4) (55°) comparing to M0 during the axial rotation, and the angle of M4 was larger. M3 and M4 increased the nucleus pulposus pressure with and without controlled angular displacement during axial rotation. The pressure of nucleus pulpous increased during M1 rotating to the abnormal side but decreased when rotating to the other side, but the results of M2 were opposite. The capsule ligament stiffness made an impact on segmental mobility and vertebral spatial position, and the sagittal angle of articular facet joint exerted an influence on disc pressure distribution.

Construction of a Statistical Cervical Vertebrae Geometric Model for Children 3-10Years Old.

Cervical spinal injuries of children in motor vehicle crashes have high morbidity and mortality rates. Cervical vertebrae change rapidly in both size and shape during growth. To accurately assess the risk of spinal injury for children of different ages, it is necessary to understand how the spatial geometric features of vertebrae change with the child's age and neck size. In this study, an innovative semi-automated method was developed that can extract and align geometric points from computed tomography scans to accurately represent complex three-dimensional vertebral geometry. Based on these spatial geometric points, a statistical cervical vertebrae geometry model for children aged 3-10 YO was established based on principal component analysis and multivariate regression. According to this model, the vertebra spatial geometries for children of different ages and neck circumferences were represented, and its variation with age were accounted for. Statistical results show that age has a significant effect on anterior-posterior length (APL), transverse process width (TPW), vertebral body circumference (VBC) and height (VBH), whereas the significance of location and its interaction with age effects on these four parameters are different. The VBC and VBH increase more rapidly with age than the APL and TPW. In addition, the APL of C6 and C7 increase significantly faster than that of C3. As for the shape changes with child growth, the inclination angle of the upper surface of the lateral mass for C1 and the tilt angle of the articular process of the articular facet joint for C3-7 increase; and the shape of odontoid process of C2 becomes higher and steeper. This study can provide geometric basis for developing multiple pediatric cervical finite element models and anthropomorphic test devices to further quantify child neck injury risk with different ages and neck geometries.

Facet joint degeneration in adolescent idiopathic scoliosis.

Adolescent idiopathic scoliosis (AIS) is a poorly understood deformity of the thoracolumbar spine which affects the intervertebral discs (IVDs) and the articular facet joints. The knowledge concerning facet joints in this context is very limited, although facet joint degeneration is a known contributor of back pain. In this study, a comprehensive investigation was performed to characterize the facet joint chondrocytes and extracellular matrix within the scoliotic spine. Surgically removed articular facet joint tissues were collected from patients undergoing spinal corrective surgery for AIS deformities, while non‐scoliotic articular facet joint tissues were obtained from cadaveric organ donors. Alterations in cartilage tissue structure were evaluated histologically with safranin‐O fast green and a modified OARSI grading scale. Pro‐inflammatory cytokines, matrix‐degrading proteases, and fragmented matrix molecules associated with cartilage degradation were analyzed by immunohistochemistry and western blotting. Safranin‐O fast green staining revealed that young scoliotic facet joints show clear signs of degeneration with substantial proteoglycan loss, similar to osteoarthritis (OA). The proteoglycan levels were significantly lower than in healthy asymptomatic non‐scoliotic control individuals. In comparison to controls, scoliotic articular facets showed increased cell density, increased expression of the proliferation marker Ki‐67, and higher expression of MMP‐3, MMP‐13, and IL‐1β. Expression and fragmentation of the small leucine‐rich proteins (SLRPs) chondroadherin, decorin, biglycan, lumican, and fibromodulin were analyzed with western blot. Chondroadherin and decorin were fragmented in cartilage from patients with a curve greater than 70°, whereas biglycan and fibromodulin did not show curve‐related fragmentation. AIS facet joint cartilage shows hallmarks of OA including proteoglycan loss, overexpression of pro‐inflammatory mediators, increased synthesis of matrix‐degrading proteases and fragmentation of SLRPs. As with patients with age‐related OA, the premature joint degeneration seen in scoliotic patients is likely to contribute to the pain perceived in some individuals.

Osseous associated cervical spondylomyelopathy at the C2-C3 articular facet joint in 11 dogs

In dogs, vertebral canal stenosis at C2-C3 due to articular facet joint degeneration is only sporadically identified. The authors’ aims were to review the clinical presentation, MRI characteristics, treatment and...

Surgical Anatomical Landmarks of the Thoracolumbar Vertebral Column on Magnetic Resonance Imaging in Dogs.

Magnetic resonance imaging (MRI) in veterinary medicine profoundly improved spinal cord disease investigation in canine patients. We aimed to further describe the anatomical landmarks of the thoracolumbar junction in sagittal MRI sequences. MRI studies from 90 dogs were reviewed retrospectively, representing a broad cross section of breeds and body weights. The ratio of the distance from the dorsal aspect of the vertebral canal to the dorsal aspect of the transverse process or rib articulation relative to the length of L2 vertebra was determined for T12, T13, L1 and L2 vertebrae. A statistically significant difference was noted with the transverse processes being more ventrally located than the cranial fovea costalis. The lumbar transverse processes and rib articulations dramatically varied in shape, being oval or round, respectively. The sagittal image at the level of the lateral margin of the articular facet joint proved to be the most consistent for review of these structures.

Quantification of Subtalar Posterior Facet Involvement During Intramedullary Guidance of Total Ankle Arthroplasty:A Cadaveric Study

Total ankle arthroplasty is an evolving treatment of ankle arthritis. One implant uses intramedullary guidance to enhance accuracy by accessing the tibial canal through the inferior aspect of the foot, potentially placing the subtalar joint articulation at risk. The purpose of the present cadaveric anatomic evaluation was to identify posterior subtalar articular facet joint involvement during intramedullary guidance to the tibial canal. Ten below-the-knee cadaveric specimens were used. After drilling into the tibial medullary canal with a 6-mm drill bit and using the standard targeting jig, the specimens were dissected, and the posterior facet was evaluated. We graded posterior facet involvement according to the location of the drill hole and, if within the facet, the percentage of the facet violated by the drill bit, with 100% representing the full circumference of the 6-mm drill bit. Of the 8 specimens in which the drill bit passed through the subtalar posterior articular facet, the encroachment was peripheral in all cases, with no specimen showing circumferential 6-mm drill bit articular penetration (no cases with 100%). Sinus tarsi penetration occurred in 20% of the cases. The dissections with articular involvement included 3 specimens with >50% of the drill bit penetrating and 5 with <50%. The portion of the posterior facet involved among the specimens that were violated was anterocentral in the joint. A risk of damage to the posterior facet of the subtalar joint exists with intramedullary total ankle systems. Our study has demonstrated that the drill bit will involve the anterocentral and anterolateral portions of the posterior facet of the subtalar joint, with <6 mm articular disruption in all cases.

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.

Congenital absence of L4–L5 articular facet joint

A 34-year-old high school teacher and dance passionate presented to our outpatient clinic for severe low back pain. His medical history was uneventful, in particular, he had no history of trauma or lumbar blockage. He complained of 4 weeks of severe pain in the back, of which the first was spent mostly at home lying in bed. Lumbar magnetic resonance imaging was prescribed, and the patient was referred to a neurosurgeon. Painkillers and anti-inflammatory drugs had little effect. Neurological examination results were normal, and pain was paravertebral right-sided and corresponding to the L4–L5 level. Lumbar magnetic resonance imaging appeared to be normal at first glance (Fig. 1) but revealed the absence of the left medial L4–L5 facet (Fig. 2). Lumbar computed tomographic scan confirmed this anomaly showing a left hypoplastic L5 superior articular process and the absence of left L4 inferior articular process (Figs. 3 and 4). Dynamic lumbar radiographs showed no signs of instability. On this basis, we assumed that the pain mechanism might be related to a mechanical stress on contralateral articulation and therefore performed a right L4–L5 articular facet steroid and anesthetic infiltration that immediately resulted in a persistent pain relief at the 2-month follow-up. Fig. 2Missing left L4–L5 facet (arrow) on axial magnetic resonance imaging T2-acquired sequences. View Large Image Figure Viewer Download Hi-res image Fig. 3Missing left L4–L5 facet on sagittal lumbar computed axial tomographic scan. The arrow indicates the absence of left L4 inferior articular process and the left hypoplastic L5 superior articular process. View Large Image Figure Viewer Download Hi-res image Fig. 4Missing left (arrow) L4–L5 facet on axial lumbar computed axial tomographic scan. View Large Image Figure Viewer Download Hi-res image

Prediction of the human thoracic and lumbar articular facet joint morphometry from radiographic images

The articular facet joints (AFJ) play an important role in the biomechanics of the spine. Although it is well known that some AFJ dimensions (e.g. facet height/width or facet angles) play a major role in spinal deformities such as scoliosis, little is known about statistical correlations between these dimensions and the size of the vertebral bodies. Such relations could allow patient-specific prediction of AFJ morphometry from a few dimensions measurable by X-ray. This would be of clinical interest and could also provide parameters for mathematical modeling of the spine. Our purpose in this study was to generate prediction equations for 20 parameters of the human thoracic and lumbar AFJ from T1 to L4 as a function of only one given parameter, the vertebral body height posterior (VBHP). Linear and nonlinear regression analyses were performed with published anatomical data, including linear and angular dimensions of the AFJ and vertebral body heights, to find the best functions to describe the correlations between these parameters. Third-order polynomial regressions, in contrast to the linear, exponential and logarithmic regressions, provided moderate to high correlations between the AFJ parameters and vertebral body heights; e.g. facet height superior and interfacet width (R², 0.605-0.880); facet height inferior, interfacet height and sagittal/transverse angle superior (R², 0.875-0.973). Different correlations were found for facet width and transverse angle inferior in the thoracic (R², 0.703-0.930) and lumbar (R², 0.457-0.892) regions. A set of 20 prediction equations for AFJ parameters was generated (P-values < 0.005, anova). Comparison of the AFJ predictions with experimental data indicated mean percent errors <13%, with the exception of the thoracolumbar junction (T12-L1). It was possible to establish useful predictions for human thoracic and lumbar AFJ dimensions based on the size of the vertebral bodies. The generated set of equations allows the prediction of 20 AFJ parameters per vertebral level from the measurement of the parameter VBHP, which is easily performed on lateral X-rays. As the vertebral body height is unique for each person and vertebral level, the predicted AFJ parameters are also specific to an individual. This approach could be used for parameterized patient-specific modeling of the spine to explore the clinically important mechanical roles of the articular facets in pathological conditions, such as scoliosis.

Congenital absence of lumbosacral articular facet joint associated with conjoined nerve root: a case report

We report a rare case of congenital absence of the L5-S1 facet joint, which was associated with a conjoined nerve root. Combination of these two anomalies has been quite rarely reported in the literature. A 39-year-old man presented with acute low back pain and right leg radiating pain. Muscle weakness and sensory disturbance of the right leg were also apparent in the region innervated by L5 and S1 nerve roots. Preoperative multidetector three-dimensional computed tomography (3D-CT) showed complete absence of the right S1 superior articular process. Magnetic resonance (MR) images showed lumbar disc herniation at right L5-S1 level that migrated cranially. Intraoperative findings revealed that the right L5 nerve root and S1 nerve root were conjoined, and the conjoined nerve root was compressed by L5-S1 disc herniation, which led to impairment of the conjoined nerve root by a single-level lumbar disc herniation. After removal of the disc herniation, his right leg pain immediately subsided, however muscle weakness and sensory disturbance persisted. Surgeons should be aware of this nerve root anomaly when examining a patient who shows an unusual clinical presentation and/or congenital osseous anomaly.

Symptomatic osteochondroma of the spine in elderly patients

Whereas osteochondroma is a common benign bone tumor in adolescence, it is rarely observed in elderly patients. It is unknown why osteochondromas, which usually develop during skeletal growth, rarely develop in elderly patients. The authors report 3 cases of symptomatic spinal osteochondroma in elderly patients and discuss the possible reasons for the onset of the enlargement of osteochondromas in elderly patients. Clinical history, radiographs, MR images, and CT myelography studies were obtained in each patient and are described. A review of the relevant literature is also presented. In the first case, the cervical osteochondroma caused spinal canal compression and occipital nerve irritation. It was totally excised, which successfully relieved the pain and allowed the patient to return to normal neurological function. In the second case, total removal of the tumor was effective in alleviating clinical symptoms. In the last case, ablation of the articular facet joint partially relieved the patient's lower-back pain. In the first 2 cases, the patients suffered from psoriasis and associated psoriatic arthritis and in the last case, the patient suffered from HIV-associated psoriatic arthritis. The psoriatic arthritis was characterized as asymmetric chronic multiple-joint arthritis and was HLA B27 positive. The pathology of psoriatic arthritis was the accelerating bone turnover and ankylosis. Symptomatic osteochondroma of the spine in elderly patients is extremely rare since it typically develops during skeletal growth. In this report, the authors show that pathological accelerating bone turnover such as psoriatic arthritis may be a possible mechanism for the onset of the enlargement of osteochondromas in elderly patients. The age of the patients in this report suggests that growth of the osteochondroma continues after skeletal development.

Pigmented villonodular synovitis of a lumbar intervertebral facet joint

Background context Pigmented villonodular synovitis (PVNS) is a slowly progressive lesion of uncertain etiology that involves the synovial membrane of joints or tendon sheaths. Only rarely does PVNS affect the axial skeleton, where it arises from the vertebral articular facet joint. Its treatment and prognosis remains limited. Purpose To describe our management in a patient with PVNS and to review previously published cases. Study design Case report. Methods This is a case report of a 59-year-old woman who presented left sciatica. Computed tomography (CT) imaging revealed a mixed sclerotic and lucent lesion affecting the left L4–L5 facet joint. Magnetic resonance imaging (MRI) demonstrated a diffusely infiltrative process that originated from the left inferior articular process of L4 vertebra with extension into the spinal canal. A total synovectomy with left L4 hemilaminectomy was performed. Left L5 root was decompressed with total microscopic tumor removal. Decompression of spinal canal and absence of the tumor was shown by MRI and CT scan after the operation. Results Complete resolution of the patient's complaints was achieved. Histopathological analysis was consistent with a diagnosis of PVNS. Conclusions The principle of surgical management of spinal lesions causing neurologic deficit is early surgical decompression. It is also important to totally remove the synovium, the origin of PVNS, to prevent the recurrence.

Spinal stability is improved by inducing a lumbar lordosis in boys with Duchenne Muscular Dystrophy: A pilot study

The development of scoliosis in boys with Duchenne Muscular Dystrophy (DMD) is a significant, morbid event in the progression of the disease caused by progressive spinal musclulature weakness. As an alternative to muscle activity, the spine can also be stabilised by locking the articular facet joints, which is achieved when the body is supported on a seat tilted anteriorly using a ‘wedge’, of the kind commonly recommended for low back pain. We tested spinal stability when using a seat tilted 15° anteriorly in eight boys with DMD, without significant scoliosis, by measuring the ability to support a lateral load applied to the thorax through a sling and hawser. All eight boys tolerated lateral loading better with wedged seating and were able to support an average additional load of 95 g per kilogram of body weight compared to normal seating. Lateral load bearing was improved in 10 normal control boys by an average of 40 g per kilogram of body weight. These encouraging pilot findings indicate that there is a need for further studies on the effectiveness of passive mechanical factors in spinal stabilisation to delay the development of scoliosis in boys with DMD.

The Inverted Napoleon's Hat Sign

Spondylolisthesis is the anterior displacement of one vertebra with respect to another and frequently occurs at the lumbosacral junction. The inverted Napoleon’s hat sign is produced when a severely subluxed L5 vertebral body (the dome of the hat) projects end-on and overlaps the sacrum, with the superimposition of images appearing as an inverted Napoleon hat (Fig 2). In the absence of a spondylolysis pars interarticularis defect or spondylolisthesis, the presence of a marked hyperlordosis at the lumbosacral junction may also simulate the appearance of the inverted Napoleon hat. The anterior slip of the L5 vertebra on S1 and the resulting L5-S1 kyphosis are counterbalanced by hyperlordosis of the lumbar spine and increased verticalization of the sacrum resulting from a compensatory hamstring contracture and uprighting of the pelvis around the hip joints (2). These factors contribute to deformities seen in spondylolisthesis and are accompanied by the potential over time to develop a pressure erosion of the anterior aspect of S1 and the posterior portion of the L5 vertebral body. In the standing position, the center of gravity normally passes through the lumbosacral joint, causing the vertebral column to slide anteriorly on the intervertebral disk at this level. The lumbosacral junction resists anterior dislocation because of the stabilization provided by the anterior longitudinal ligament, the posterior bands of the iliolumbar ligaments, and the articular facet joints (3). The facet joint anatomy normally helps prevent slippage on the anteroinferiorly directed sacral promontory at the lumbosacral junction by means of the inferior articular facets of L5, which are anteriorly oriented and engage the posteriorly directed S1 articular facets (3). An approximately 140° angle normally exists between L5 and the sacral axis, along with a 40° angle of the S1 body from the horizontal, thereby contributing to the large amount of force imposed onto the superior articular processes of S1 (3). Notable disruption of any of these stabilizing forces may result in depiction of the inverted Napoleon’s hat sign.