Spinal Facet Joint Research Articles

Effect of multilevel lumbar disc arthroplasty on spine kinematics and facet joint loads in flexion and extension: a finite element analysis

Total disc arthroplasty (TDA) has been successfully used for monosegmental treatment in the last few years. However, multi-level TDA led to controversial clinical results. We hypothesise that: (1) the more artificial discs are implanted, the stronger the increases in spinal mobility and facet joint forces in flexion and extension; (2) deviations from the optimal implant position lead to strong instabilities. A three-dimensional finite element model of the intact L1-L5 human lumbar spine was created. Additionally, models of the L1-L5 region implanted with multiple Charité discs ranging from two to four levels were created. The models took into account the possible misalignments in the antero-posterior direction of the artificial discs. All these models were exposed to an axial compression preload of 500 N and pure moments of 7.5 Nm in flexion and extension. For central implant positions and the loading case extension, a motion increase of 51% for two implants up to 91% for four implants and a facet force increase of 24% for two implants up to 38% for four implants compared to the intact spine were calculated. In flexion, a motion decrease of 5% for two implants up to 8% for four implants was predicted. Posteriorly placed implants led to a better representation of the intact spine motion. However, lift-off phenomena between the core and the implant endplates were observed in some extension simulations in which the artificial discs were anteriorly or posteriorly implanted. The more artificial discs are implanted, the stronger the motion increase in flexion and extension was predicted with respect to the intact condition. Deviations from the optimal implant position lead to unfavourable kinematics, to high facet joint forces and even to lift-off phenomena. Therefore, multilevel TDA should, if at all, only be performed in appropriate patients with good muscular conditions and by surgeons who can ensure optimal implant positions.

Facet Orientation and Tropism

Cross-sectional study. To evaluate the association between lumbar spine facet joint orientation, facet joint tropism, and spondylolysis identified by multidetector computed tomography (CT) in the community-based Framingham Heart Study. The association between lumbar spondylolysis and facet orientation and tropism remains unclear. This study was an ancillary project to the Framingham Heart Study. Three thousand five hundred twenty-nine participants of the Framingham Heart Study aged 40 to 80 years underwent multidetector CT imaging to assess aortic calcification. One hundred ninety-one subjects were included in this ancillary study. Facet joint features and spondylolysis were evaluated on CT scans. The final analyzed sample included 104 men with mean age 51.90+/-11.25 years and 84 women with mean age 53.61+/-10.20 years. The association between spondylolysis and facet orientation and tropism was examined using univariate and multivariate analyses. Spondylolysis was prevalent in 11.5% of the total population. chi2 test demonstrated a significant sex difference in prevalence of spondylolysis (P=0.0154), with almost 3 times higher prevalence among men. There was no statistically significant difference in facet orientation and continuous facet tropism between individuals with and without spondylolysis at the L5 level (P=0.49 to 0.91). After adjustment for age, sex, and body mass index, no significant association between the occurrence of spondylolysis and facet orientation and tropism was found. In the studied sample the prevalence of facet joint osteoarthritis was significantly higher in individuals with spondylolysis than in those without spondylolysis at both sides of L4-L5 spinal level (P=0.044 at the right side and P=0.003 at the left side) and at left side of L5-S1 level (P=0.038). We did not find an association between facet orientation, facet tropism, and spondylolysis. One of the possible explanations for this is that the high prevalence of facet joint osteoarthritis in individuals with spondylolysis in the studied sample might have led to diminished differences in facet orientation.

Non-fatal injuries to the cervical spine facet joints after a fatal motor vehicle crash

Injuries to the lower cervical spine facet joints may be identified in people killed in road traffic crashes. However, many of these injuries are not identified on diagnostic imaging procedures despite histological evidence of injury. This case report illustrates possible non-lethal pathological conditions in the facet joints following fatal road traffic trauma. The cervical spine segments C4 to C7 were removed en bloc and examined with magnetic resonance imaging, computed tomography and conventional radiology. The specimen was fixated in alcohol, embedded in methylmethacrylate, and divided into 3 mm thick parasaggital slices from where 10 microm thick sections were produced and evaluated with light microscopy. Injuries identified on microscopy included haemarthrosis, capsular avulsion, synovial fold contusions and subchondral fractures. None of the injuries were detected on diagnostic imaging or at routine autopsy. Discrete injuries to the cervical spine facet joints were identified using supplemental histological procedures in this case report. Post-mortem diagnostic imaging did not reveal these injuries and future studies should investigate the nature, prevalence and clinical relevance of such lesions.

Facet Orientation and Tropism

Cross-sectional study.To evaluate the association between lumbar spine facet joint orientation, facet joint tropism, and facet joint osteoarthritis (OA) and degenerative spondylolisthesis (DS) identified by multidetector computed tomography in the community-based Framingham Heart Study.The association between lumbar facet joint OA, DS, and facet orientation and tropism remains unclear. METHODS.: This study was an ancillary project to the Framingham Heart Study. A sample of 3529 participants of the Framingham Heart Study aged 40 to 80 underwent multidetector computed tomography imaging to assess aortic calcification. One hundred eighty-eight individuals were consecutively enrolled in this ancillary study to assess radiographic features associated with low back pain. Facet joint OA was evaluated at the L3-L4, L4-L5, and L5-S1 spinal levels, using a 4-grade scale. The association between facet joint OA, DS, and facet orientation, and tropism was examined using multiple logistic regression models adjusting for age, sex, and body mass index.At each spinal level the facet joints with OA were more sagittally oriented than those without OA, but the difference was statistically significant only at L4-L5 spinal level (P = 0.0007). Facet tropism did not show an association with facet joint OA at any spinal level. Facet orientation was significantly associated with DS (0.89 [0.84-0.94]), however, facet tropism showed no association with DS.The current study confirms a significant association between sagittal orientation and OA of the lumbar facet joints at L4-L5 and DS. Facet tropism was not associated with occurrence of facet joint OA or DS. Additional, longitudinal studies are needed to understand the causal relationship between facet joint morphology and OA.

Imaging Occult Lesions in the Cervical Spine Facet Joints

Discrete injuries in the lower cervical spine facet joints have been reported in studies of motor vehicle crash victims. We conducted a detailed investigation of these joints from 20 motor vehicle crash fatalities and 22 decedents due to nontraumatic causes, using conventional radiology, computed tomography, and magnetic resonance imaging to examine whether the diagnostic imaging procedures could identify injuries in the facet joints. The diagnostic imaging procedures identified facet joint fractures in 4 of the 19 trauma cases with computed tomography having the highest sensitivity and obtaining good correlation with findings from the microscopical evaluation. No diagnostic imaging procedure could reliably evaluate the integrity of the synovial folds or the joint spaces for bleeding despite microscopical evidence of such findings in these structures in a large proportion of the motor vehicle crash fatalities. This study emphasizes the need for scientific evidence of validity and reliability of advanced diagnostic imaging procedures in forensic settings, in particular, with regard to occult soft tissue lesions, and cautions uncritical use of negative results from these procedures until such evidence has been produced.

The characteristics of bony ankylosis of the facet joint of the upper cervical spine in rheumatoid arthritis patients

This study investigated the bony ankylosis of the upper cervical spine facet joints in patients with a cervical spine involvement due to rheumatoid arthritis (RA) using computed tomography (CT) and then examined the characteristics of the patients showing such ankylosis. Forty-six consecutive patients who underwent surgical treatment for RA involving the cervical spine were reviewed. The radiographic diagnoses included atlanto-axial subluxation in 30 cases, vertical subluxation (VS) in 10 cases, VS + subaxial subluxation in 3 cases and cervical spondylotic myelopathy in 3 cases. The patients were classified into two groups, those developing bony ankylosis or not and then the differences in the patient characteristics between the two groups was investigated. Furthermore, cervical spine disorders and surgeries were also evaluated in patients who demonstrated such bony ankylosis. The CT reconstruction image demonstrated bony ankylosis in 12 patients (group BA), and the remaining 34 cases (group NB) showed no bony ankylosis. The level at which bony ankylosis occurred was atlanto-occipital joint (AOJ) in eight cases, atlanto-axial joint (AAJ) in two cases and AOJ, AAJ in two cases. No differences were observed between the two groups (age P > 0.54, gender P > 0.39, duration of RA P > 0.72). There was a significant difference between two groups in the patients showing obvious neurological impairment (P = 0.017). In BA group, arthrodesis or decompression was adapted for a caudal region of bony ankylosis. In conclusion, bony ankylosis of the facet joint of the upper cervical spine was detected in 12 of 46 RA patients with involvement of the cervical spine who thus required surgery. These findings showed that the patients demonstrating such ankylosis showed severe cervical myelopathy. In addition, we suggest that the occurrence of bony ankylosis was a risk factor for instability of AAJ, and subaxial instability or stenosis.

Pathoanatomy of the lower cervical spine facet joints in motor vehicle crash fatalities

Non-lethal injuries to the cervical spine facet joints have previously been described in decedents from motor vehicle crashes and in clinical settings these joints have been identified as potential culprits in chronic neck pain syndromes. The aim of this study was to conduct a detailed examination of the lower cervical spine facet joints in a forensic cohort of motor vehicle crash victims and controls using comparable data from medicolegal autopsy, stereomicroscopy and histological evaluations. Injuries to the cervical spine facet joints were common in the trauma cases and included facet fractures, haemarthrosis, and disruption and bleeding in the synovial folds. The injuries could not be reliably verified on stereomicroscopic evaluation, and routine autopsy procedures did not reveal any of the injuries to the facet joints. Despite the presence of these pathoanatomical lesions in road traffic crash fatalities their prevalence and potential clinical implications in survivors from motor vehicle crashes is unknown.

Facet Joint Osteoarthritis and Low Back Pain in the Community-Based Population

Cross-sectional study. To evaluate the association between lumbar spine facet joint osteoarthritis (FJ OA) identified by multidetector computed tomography (CT) and low back pain (LBP) in the community-based Framingham Heart Study. The association between lumbar FJ OA and LBP remains unclear. This study was an ancillary project to the Framingham Heart Study. A sample of 3529 participants of the Framingham Heart Study aged 40 to 80 underwent multidetector CT imaging to assess aortic calcification. One hundred eighty-eight individuals were consecutively enrolled in this ancillary study to assess radiographic features associated with LBP. LBP in the preceding 12 months was evaluated using a self-report questionnaire. FJ OA was evaluated on CT scans using a 4-grade scale. The association between FJ OA and LBP was examined used multiple logistic regression models, while adjusting for gender, age, and BMI. CT imaging revealed a high prevalence of FJ OA (59.6% of males and 66.7% of females). Prevalence of FJ OA increases with age. By decade, FJ OA was present in 24.0% of <40-years-olds, 44.7% of 40- to 49-years-olds, 74.2% of 50- to 59-years-olds, 89.2% of 60- to 69-year-olds, and 69.2% of >70-years-olds. By spinal level the prevalence of FJ OA was: 15.1% at L2-L3, 30.6% at L3-L4, 45.1% at L4-L5, and 38.2% at L5-S1. In this community-based population, individuals with FJ OA at any spinal level showed no association with LBP. There is a high prevalence of FJ OA in the community. Prevalence of FJ OA increases with age with the highest prevalence at the L4-L5 spinal level. At low spinal levels women have a higher prevalence of lumbar FJ OA than men. In the present study, we failed to find an association between FJ OA, identified by multidetector CT, at any spinal level and LBP in a community-based study population.

Imaging diagnosis of juvenile simple disorder of vertebrae

Objective To explore the pathogenesis of juvenile disorders of spine facet joints and to clarify the diagnosis by concluding the clinical and imaging manifestations.Methods Retrospectively analyzed imaging data of 250 patients from 10～30 years with disorders of spine facet joints including X-ray and CT and MRI.Results Reasons of juvenile disorders of spine facet joints has unique imaging manifestations of asymmetric of small joints and joint surface hyperplasia like pen,of nonspecial inflammation in surrounding soft tissue.Conclusions Imaging can diagnose and differentiate diagnosis juvenile disorder of spine facet joints.X-ray is also the primary method.Not only.CT or MRI image can more clearly display the changes of spine facet joints and surrounding soft tissue,but also differentiate diagnosis disc henaiation and other diseases. Key words: Spine; Facet joint; Radiography; Tomography; X-ray computed; Magnetic resonance imaging

Biomechanical effect of different lumbar interspinous implants on flexibility and intradiscal pressure

Interspinous implants are used to treat lumbar spinal stenosis or facet joint arthritis. The aims of implanting interspinous devices are to unload the facet joints, restore foraminal height and provide stability especially in extension but still allow motion. The aim of this in vitro study was to compare four different interspinous implants--Colfex, Wallis, Diam and X-Stop--in terms of their three-dimensional flexibility and the intradiscal pressure. Twenty-four human lumbar spine specimens were divided into four equal groups and tested with pure moments in flexion/extension, lateral bending and axial rotation: (1) intact, (2) defect, (3) after implantation. Range of motion and the intradiscal pressure were determined. In each implant-group the defect caused an increase in range of motion by about 8% in lateral bending to 18% in axial rotation. Implantation had similar effects with all four implants. In extension, Coflex, Wallis, Diam, and X-Stop all overcompensated the instability caused by the defect and allowed about 50% of the range of motion of the intact state. In contrast, in flexion, lateral bending and axial rotation the values of the range of motion stayed about the values of the defect state. Similarly the intradiscal pressure after implantation was similar to that of the intact specimens in flexion, lateral bending and axial rotation but much smaller during extension. All tested interspinous implants had a similar effect on the flexibility: they strongly stabilized and reduced the intradiscal pressure in extension, but had almost no effect in flexion, lateral bending and axial rotation.

In Vitro Three Dimensional Morphometry of the Lateral Atlantoaxial Articular Surfaces

The present study verifies the 3-dimensional anatomic features of the lateral atlantoaxial joints with reference to a local reference frame using a direct in vitro approach. To study the concordance between the axial and atlantal articular surfaces. Detailed information of joint-configurations is imperative for understanding the complex kinematics of the upper cervical joint. Data on the quantitative morphology of the human spinal facet joints has been published, but did not include the atlanto-occipital and atlantoaxial joints. In 20 fresh spine specimens, metal markers were implanted on the cranium, the atlas, and the axis. After registration of the intact specimens, the bony segments were separated and markers and anatomic landmarks were digitized. The size, shape, and orientation relative to the local reference frame of the axis were derived from the relative position data of the joint surface landmarks. The diameters and surface areas of the inferior articular surfaces of the atlas are slightly smaller than the corresponding surfaces on the superior aspects of the axis (17.7 mm and 235 mm vs. 17.0 and 212 mm). In this sample of older-aged specimens, the curvature of the articulating surfaces is nearly flat. The absolute angle between the left and right surface areas is about 130 degrees and corresponds well between axis and atlas. The orientation of the joint surfaces of axis and atlas with respect to the sagittal plane of the axis indicates a good congruency. There seems to be a strong relationship between the anatomic features of the lateral articulating surfaces of atlas and axis. Differences in the orientation of joint surfaces to the frontal plane may be related to deviations from the neutral position. This issue raises the problem of the definition of three-dimensional-neutral joint positions.

Can extra-articular strains be used to measure facet contact forces in the lumbar spine? An in-vitro biomechanical study

Experimental measurement of the load-bearing patterns of the facet joints in the lumbar spine remains a challenge, thereby limiting the assessment of facet joint function under various surgical conditions and the validation of computational models. The extra-articular strain (EAS) technique, a non-invasive measurement of the contact load, has been used for unilateral facet joints but does not incorporate strain coupling, i.e. ipsilateral EASs due to forces on the contralateral facet joint. The objectives of the present study were to establish a bilateral model for facet contact force measurement using the EAS technique and to determine its effectiveness in measuring these facet joint contact forces during three-dimensional flexibility tests in the lumbar spine. Specific goals were to assess the accuracy and repeatability of the technique and to assess the effect of soft-tissue artefacts. In the accuracy and repeatability tests, ten uniaxial strain gauges were bonded to the external surface of the inferior facets of L3 of ten fresh lumbar spine specimens. Two pressure-sensitive sensors (Tekscan) were inserted into the joints after the capsules were cut. Facet contact forces were measured with the EAS and Tekscan techniques for each specimen in flexion, extension, axial rotation, and lateral bending under a +/- 7.5 N m pure moment. Four of the ten specimens were tested five times in axial rotation and extension for repeatability. These same specimens were disarticulated and known forces were applied across the facet joint using a manual probe (direct accuracy) and a materials-testing system (disarticulated accuracy). In soft-tissue artefact tests, a separate set of six lumbar spine specimens was used to document the virtual facet joint contact forces during a flexibility test following removal of the superior facet processes. Linear strain coupling was observed in all specimens. The average peak facet joint contact forces during flexibility testing was greatest in axial rotation (71 +/- 25 N), followed by extension (27 +/- 35 N) and lateral bending (25 +/- 28 N), and they were most repeatable in axial rotation (coefficient of variation, 5 per cent). The EAS accuracy was about 20 per cent in the direct accuracy assessment and about 30 per cent in the disarticulated accuracy test. The latter was very similar to the Tekscan accuracy in the same test. Virtual facet loads (r.m.s.) were small in axial rotation (12 N) and lateral bending (20 N), but relatively large in flexion (34 N) and extension (35 N). The results suggested that the bilateral EAS model could be used to determine the facet joint contact forces in axial rotation but may result in considerable error in flexion, extension, and lateral bending.

Degenerative and traumatic changes in the lower cervical spine facet joints

Objective: The aim of this study was to examine anatomical variables of the lower cervical spine facet joints with regard to age, gender, and exposure to trauma.Methods: The lower four cervical spine segments (C4–C7 included) were obtained from 40 subjects during autopsy: 12 females and 28 males (median age 35 years, range 20–49). Through an available 636 unique facets (318 joints), 1830 randomly obtained observation lines were defined. Each of these lines resembled a 3‐mm‐thick parasaggital slice through a facet from which 10‐µm‐thick histological sections were produced and evaluated microscopically. Inter‐ and intraobserver agreement was tested on four randomly selected facets from each subject.Results: Significant age‐, gender‐, and trauma‐related changes in the bone, cartilage, and soft tissues were observed, including subchondral sclerosis, fibrillation and splitting of cartilage, and cartilage length differences. Females were less affected by changes in the cartilage than males. Two synovial folds were present in all but one joint. Moderate interobserver and good intraobserver agreement were achieved.Conclusions: This study provides knowledge of the anatomy of the cervical spine facet joints. The findings support existing knowledge that males are more commonly affected by degenerative changes than females and that these changes are common from a young age. Histomorphometry confirms the presence of synovial folds in all of the facet joints. Following spinal trauma, pathological lesions may be produced in the facet joints and/or accentuate already existing pathology. The information provided in this study may have relevance for patients with neck pain.

Ultrasound-Guided Versus Computed Tomography-Controlled Facet Joint Injections in the Lumbar Spine: A Prospective Randomized Clinical Trial

Facet joint injections are widely used for alleviation of back pain. Injections are preferentially performed as fluoroscopy or computed tomography (CT)-controlled interventions. Ultrasound provides real-time monitoring, does not produce ionizing radiation, and is broadly available. We studied feasibility, accuracy, time-savings, radiation doses, and pain relief of ultrasound-guided facet joint injections versus CT-controlled interventions in a prospective randomized clinical trial. Forty adult patients with chronic low back pain were consecutively enrolled and evenly assigned to an ultrasound or a CT- group. Eighteen subjects from the group randomized to ultrasound were judged to be feasible for this type of approach. In 16 of them the facet joints were clearly visible and all of the associated facet joint injections were performed correctly. The duration of procedure and radiation dose was 14.3 +/- 6.6 minutes and 14.2 +/- 11.7 mGy.cm in the ultrasound group, and 22.3 +/- 6.3 minutes and 364.4 +/- 213.7 mGy.cm in the CT group. Both groups showed a benefit from facet joint injections. The ultrasound approach to the facet joints in the lumbar spine is feasible with minimal risks in a large majority of patients and results in a significant reduction of procedure duration and radiation dose.

Systematic Review Of Diagnostic Utility Of Facet (Zygapophysial) Joint Injections In Chronic Spinal Pain: An Update

A 2-year review of literature from October 2004 to December 2006 was completed to update current scientific evidence on diagnostic utility of facet joint injections. Diagnostic injections are employed to diagnose facet joint pain because available techniques cannot identify the pain generating structure in patients with chronic spinal pain. There is no physical examination technique, laboratory test, or imaging modality that can precisely identify the spinal structure causing pain, distinguish the culprit from a variety of potential targets, and predict response to a therapeutic intervention. Zygapophysial joint injections, commonly called facet injections (intraarticular joint injections and medial branch blocks) are local anesthetic injections of the facet joint or its nerve supply. These are diagnostic procedures used to determine if pain is arising from facet joints, distinguish painful from nonpainful joints and prognosticate response to therapeutic facet joint interventions. Diagnostic injections must meet the cardinal features of a diagnostic test i.e., accuracy, safety, and reproducibility. Accuracy is based on comparison with a "gold standard" to confirm presence or absence of a disease. There is, however, no available gold standard to measure presence or absence of pain. Hence, there is a degree of uncertainty concerning the accuracy of diagnostic facet joint injections. Evaluate and update available evidence (2004 to 2006) relating to clinical utility of facet joint injections (intraarticular and medial branch blocks) in diagnosing chronic spinal pain of facet joint origin. Review of the literature for clinical studies on efficacy and utility of facet joint/nerve injections in diagnosing facet joint pain according to Agency for Healthcare Research and Quality (AHRQ) and Quality Assessment Studies of Diagnostic Accuracy (QUADAS) criteria. The level of evidence was classified as conclusive (Level I), strong (Level II), moderate (Level III), or limited (Level IV). Computerized database search (2004 to 2006) of PUBMED, EMBASE, CINAHL, and Web of Knowledge was conducted to identify studies on facet joint pain and diagnostic interventions. Abstracts, reviews, book chapters, case reports, studies based on single blocks or blocks without radiologic control, and studies describing techniques were excluded. Prospective studies were given priority over retrospective studies. There is no change in the strength of evidence for facet joint diagnostic injections. There is strong evidence for controlled comparative local anesthetic facet joint injections or medial branch blocks in the diagnosis of neck and low back pain and moderate evidence in the diagnosis of pain arising from thoracic facet joints. The evidence obtained from literature review suggests that controlled comparative local anesthetic blocks of facet joints (medial branch or dorsal ramus) are reproducible, reasonably accurate and safe. The sensitivity, specificity, false-positive rates, and predictive values of these diagnostic tests for neck and low back pain have been validated and reproduced in multiple studies.

P47. The Effect of Decreasing the Cervical Disc Space Height on the Facet Joint

BACKGROUND CONTEXT: Some change in disc space height is usually seen after inserting an artificial disc. It has already been reported by the current authors that there is an adverse effect on the facet joint as a result of increasing disc space height. To date, no study has addressed the effect that decreasing disc space height has on the facet joints in the cervical spine.

Diagnosis and management of juxtafacet cysts

Juxtafacet cysts are lesions that are associated with spinal facet joints. Although these lesions are frequently noted as incidental findings on imaging studies of the spine, they may produce symptoms in some patients. Juxtafacet cysts can mimic herniated discs, resulting in symptoms from focal nerve root and/or spinal cord compression. Some of these lesions are associated with spinal instability, and patients may require spinal fusion to address this underlying disorder. Conservative therapy for symptomatic lesions is often unsuccessful, although there are reports of spontaneous resolution of these cysts as well as the symptoms associated with them. Surgical therapy should be focused on decompression of the lesions causing nerve root compression and the accompanying symptoms, while recognizing that instability requiring fusion may be present in some but not all cases.

Resolution of a synovial cyst of the lumbar spine without surgical therapy — A case report

Synovial cysts originating from the facet joint of the lumbar spine are a rare cause of radiculopathy. Surgical resection is considered to be the treatment of choice, although very little is known about the natural history of spinal synovial cysts. Only six cases have been published up to now concerning the spontaneous regression of a cyst without invasive therapy. We present the history of a patient suffering from sciatic pain caused by a synovial cyst at the level of L4/5, and we describe the spontaneous remission of the cyst, discussing the radiological and clinical findings and comparing our findings with respect to the current literature. Clinical presentation The patient suffered from sciatic pain for 5 months without neurological deficits. Magnetic resonance tomography revealed a cystic structure adjacent to the facet joint L4/5. Presuming a synovial cyst, we scheduled surgery and at the same time started conservative treatment, including physical therapy and analgesic medication. The patient's condition improved significantly during conservative treatment, so that surgery was cancelled. A second magnetic resonance tomography showed that the cyst had dramatically shrunken, without any narrowing of the spinal canal. Conclusions Up to now, synovial cysts of the lumbar spine have usually been treated operatively, but we and others have shown that spontaneous resolution of the cyst seems possible, so that extensive conservative treatment should always be considered as the first therapeutic option, provided that there are no severe neurological deficits.

Treatment of symptomatic adjacent-segment degeneration after lumbar fusion with total disc arthroplasty by using the ProDisc prosthesis: a prospective study with 2-year minimum follow up

The authors conducted a prospective longitudinal study to assess the efficacy of ProDisc arthroplasty in patients in whom symptomatic adjacent-segment degeneration has developed after remote lumbar fusion. The follow-up period was a minimum of 2 years. The 20 patients in this study ranged in age from 18 to 67 years. They presented with disabling adjacent-level discogenic low-back pain with or without L1-S1 radicular pain. Patients with radiographic evidence of circumferential spinal stenosis or facet joint degeneration had been excluded. Patients were assessed preoperatively and postoperatively at 3, 6, 12, and 24 months. Eighteen patients (90%) fulfilled all follow-up criteria. The median age of all patients was 50 years. Statistical improvements in visual analog scale, Oswestry Disability Index, and patient satisfaction scores were documented 3 months after arthroplasty. These improvements remained at the 24-month follow-up examinations. Patient satisfaction rates were 86% at 24 months. Radicular pain was also significantly decreased. No additional surgeries were necessary at affected or unaffected levels. Analysis of early results indicates that ProDisc lumbar total disc arthroplasty is an efficacious treatment for symptomatic adjacent-segment lumbar discogenic low-back pain following remote fusion. Significant improvements in patient satisfaction and disability scores were observed by 3 months postoperatively and were maintained at the 2-year follow-up examination. No device-related complications occurred. Patients should be screened carefully for evidence of facet joint impingement/degeneration, hardware-induced pain, and/or nonunion at prior fusion levels before undergoing disc replacement surgery.

Examination of Cervical Spine Histological Sections—A Technical Note

AbstractThe cervical spine facet joints have a central role in chronic pain syndromes following whiplash injuries. In order to improve our understanding of these pain syndromes, a detailed knowledge of the cervical spine anatomy and morphology is needed. Hence, a detailed examination of the cervical spine articular structures is needed and for this purpose we present a specialized histological method that may be employed in post-mortem studies.