The lumbar facet joint: a review of current knowledge: part 1: anatomy, biomechanics, and grading

Exploring the Influence of Facet Orientation and Tropism on Neutral Zone Properties

Lumbar spine pathologies have been linked independently to both neutral zone (NZ) properties and facet joint anatomical characteristics; however, the effect of facet joint orientation (FO) and tropism (FT) on NZ properties remains unclear. The aim of the present study was to investigate how axial plane FO and FT relate to NZ range and stiffness in the human lumbar spine and porcine cervical spine. Seven human lumbar functional spine units (FSUs) and 94 porcine cervical FSUs were examined. FO and FT were measured, and in vitro mechanical testing was used to determine anterior-posterior (AP) and flexion-extension (FE) NZ range and stiffness. FO and FT were found to have no significant relationship with AP and FE NZ range. Increases in FT were associated with greater FE and AP NZ stiffness in human FSUs, with no FT-NZ stiffness relationship observed in porcine specimens. A significant relationship (p < 0.001) between FO and FE NZ stiffness was observed for both porcine and human FSUs, with a more sagittal orientation of the facet joints being associated with decreased FE NZ stiffness. Given the link between NZ stiffness and pathological states of the lumbar spine, further research is warranted to determine the practical significance of the observed facet joint anatomical characteristic-NZ property relationship.

Exploration of the correlation between facet joints cross-sectional area asymmetry and cervical disc herniation

PURPOSE

To evaluate the association between facet joints cross-sectional area asymmetry (FCAA) and cervical intervertebral disc herniation (CDH).

METHODS

Overall, we retrospectively recruited 390 consecutive patients with CDH who underwent surgical treatment at our institution and 50 normal participants. Clinical variables and radiological findings related to CDH were collected.

RESULTS

Patients with CDH were more likely to have a higher absolute value of the facet asymmetry factor (FAF) (p  < .001), in which the FAF value of the left group was significantly higher than the other groups (p  < .001) and the right group was lower than the central group (p  < .001). 9.62% (C3/4), 12.19% (C4/5), 8.70% (C5/6), and 8.14% (C6/7) were determined as cutoff values for each variable that maximized sensitivity and specificity. Furthermore, multivariate analysis showed that cross-sectional area asymmetry of the facet joint (FCAA) was an independent risk factor for the occurrence of CDH. Also, the Chi-square test showed a significant difference in the distribution of the degeneration classification of the disc between the facet-degenerated group and the nondegenerated group at C5/6 (p = 0.026) and C6/7 (p = 0.005) in the facet asymmetry (FA) group.

CONCLUSIONS

FCAA is evaluated as an independent risk factor for CDH and associated with the orientation of disc herniation. And facet joint orientation may also play a role in cervical spine degeneration rather than facet joint tropism.

Facet joint involvement in the inflammatory rheumatic disease

BACKGROUND

The involvement of facet joints (FJ) in patients with inflammatory rheumatic disorders remains underexplored. This review aims to look at FJ disease from a rheumatologist's perspective, with the emphasis given to the clinical presentations and patterns of FJ engagement in axial spondyloarthritis (axSpA), psoriatic arthritis (PsA), rheumatoid arthritis (RA), and crystal-related arthropathies, and discussion of challenges in studying FJ in rheumatic disease.

METHODS

A systematic PubMed search using the pertinent keywords was performed, relevant articles extracted, and the acquired data critically assessed, interpreted, and organized according to the authors' experience and judgment.

RESULTS

FJ involvement is common in patients with radiographic axSpA, occurs throughout the spine, but is more frequently seen in the thoracic segment. The existing data suggests that the FJ are primarily affected by the disease process, while altered spine biomechanics due to the presence of syndesmophytes at the same vertebral level contributes to the FJ fusion. Predominant involvement of FJ of the cervical spinal segment has been suggested in PsA; however, prevalence and clinical significance of FJ involvement in PsA is still markedly underexplored. RA-related FJ disease of the cervical spine in patients with poorly controlled RA is not uncommon and can be related to significant morbidity, while the burden of FJ involvement in the thoracic and lumbar spinal segments in RA is also underexplored. FJ disease is possible in the course of crystal-related arthropathies, but the high level of suspicion is a prerequisite for the timely diagnosis.

CONCLUSIONS

The involvement of FJ in the course of inflammatory rheumatic disease is not uncommon. Prospective studies are needed to understand the epidemiology and significance of FJ disease in inflammatory rheumatic conditions.

Exosomes for the Management of Low Back Pain: A Review of Current Clinical Evidence

Low back pain affects millions of people, creating an enormous financial burden on the global healthcare system. Traditional treatment modalities are short-lived and have shortcomings. Recently, orthobiologics, including extracellular vesicles or exosomes derived from mesenchymal stem cells, have markedly increased for managing musculoskeletal conditions. Here, the primary aim is to review the outcomes of clinical studies using extracellular vesicles or exosomes for treating low back pain. Numerous databases (Scopus, PubMed, Web of Science, Embase, and Google Scholar) were searched using terms for the intervention 'exosomes' and the treatment 'low back pain' for studies published in English to March 18, 2024. Articles utilizing exosomes for the management of low back pain were included. Articles not utilizing exosomes, not explicitly stating the presence of exosomes in their formulation, or not targeting low back pain were excluded. Two articles that met our pre-defined criteria were included in this review. The results showed that administering extracellular vesicles or exosomes is safe and potentially effective in patients suffering from low back pain. Yet, more sufficiently powered, multi-center, prospective, randomized, and non-randomized trials with longer follow-up are essential to assess the long-term safety and efficacy of extracellular vesicles or exosomes derived from various sources and to support its routine clinical use for managing low back pain.

Association between facet joint orientation/tropism and lumbar intervertebral disc degeneration

Background: The aim of this study was to understand how facet joint orientation (FJO) and facet joint tropism (FJT) affected severe intervertebral disc degeneration (IVDD) process at lower lumbar levels in patients with LBP.Methods: This study is a cross-sectional analysis of a retrospective database. Patients were evaluated in terms of IVDD, FJO, and FJT at all lumbar levels on magnetic resonance imaging.Results: In this study (n: 123) facet joints were aligned more coronal in men than in women at upper lumbar levels. Men had less FJT compared to women, significantly at L2-L3 and L3-L4 levels. Severe IVDD at L4-L5 was associated with more coronal aligned L1-L2 (29.0 ± 2.5° vs. 23.3 ± 2.3°, p = 0.006) and misaligned L5-S1 (8.3 ± 1.9° vs. 4.5 ± 1.7°, p = 0.008). Besides, severe IVDD at L3-L4 was associated with more coronal aligned L4-L5 (49.1 ± 3.2° vs. 41.4 ± 2.8°, p = 0.014).Conclusion: There is a close association between FJO/FJT with lumbar IVDD. Facet joint orientation and FJT do not affect the disc at only the corresponding level; the lumbar spine should be evaluated as a whole.

Analyzing isolated degeneration of lumbar facet joints: implications for degenerative instability and lumbar biomechanics using finite element analysis

The facet joint contributes to lumbar spine stability as it supports the weight of body along with the intervertebral discs. However, most studies on the causes of degenerative lumbar diseases focus on the intervertebral discs and often overlook the facet joints. This study aimed to investigate the impact of facet joint degeneration on the degenerative changes and diseases of the lumbar spine. A finite element model of the lumbar spine (L1-S1) was fabricated and validated to study the biomechanical characteristics of the facet joints. To simulate degeneration of the facet joint, the model was divided into four grades based on the number of degenerative segments (L4-L5 or L4-S1) and the contact condition between the facet joint surfaces. Finite element analysis was performed on four spine motions: flexion, extension, lateral bending, and axial torsion, by applying a pure moment to the upper surface of L1. Important parameters that could be used to confirm the effect of facet joint degeneration on the lumbar spine were calculated, including the range of motion (ROM) of the lumbar segments, maximum von Mises stress on the intervertebral discs, and reaction force at the facet joint. Facet joint degeneration affected the biomechanical characteristics of the lumbar spine depending on the movements of the spine. When analyzed by dividing it into degenerative onset and onset-adjacent segments, lumbar ROM and the maximum von Mises stress of the intervertebral discs decreased as the degree of degeneration increased in the degenerative onset segments. The reaction force at the facet joint decreased with flexion and increased with lateral bending and axial torsion. In contrast, lumbar ROM of the onset-adjacent segments remained almost unchanged despite severe degeneration of the facet joint, and the maximum von Mises stress of the intervertebral discs increased with flexion and extension but decreased with lateral bending and axial torsion. Additionally, the facet joint reaction force increased with extension, lateral bending, and axial rotation. This analysis, which combined the ROM of the lumbar segment, maximum von Mises stress on the intervertebral disc, and facet joint reaction force, confirmed the biomechanical changes in the lumbar spine due to the degeneration of isolated facet joints under the load of spinal motion. In the degenerative onset segment, spinal instability decreased, whereas in the onset-adjacent segment, a greater load was applied than in the intact state. When conducting biomechanical studies on the lumbar spine, considering facet joint degeneration is important since it can lead to degenerative spinal diseases, including adjacent segment diseases.

Facet joint tropism, pelvic incidence and intervertebral height index: associations with facet joint osteoarthritis in lumbar spinal stenosis

BACKGROUND CONTEXT

Facet joint osteoarthritis (FJOA) is associated with lumbar disc degeneration and has a significant role in the development of lumbar spinal stenosis (LSS). The relationship between various radiographic parameters and the grade of FJOA is not well understood.

PURPOSE

To explore radiographical parameters associated with FJOA in LSS without lumbar dynamic instability.

STUDY DESIGN

Retrospective study analysis.

PATIENT SAMPLE

A total of 122 patients diagnosed with LSS who visited our hospital between January 2015 and July 2022.

OUTCOME MEASURES

We evaluated radiographic parameters of patients at L4-5 including lumbar lordosis (LL), pelvic incidence (PI), pelvic tilt (PT), sacral slope (SS), grades of FJOA, facet joint orientation (FO), facet joint tropism (FT), intervertebral height index (IHI) and the relative cross-sectional area (RCSA) of paraspinal muscles.

METHODS

Patients diagnosed with LSS between January 2015 and July 2022 were enrolled. Demographic characteristics and radiographic parameters were collected. Spinopelvic parameters were measured through the preoperative lateral image of the whole spine, including LL, PI, pelvic tilt, and sacral slope. Lumbar computed tomography scan and magnetic resonance imaging were collected to measure the FO, FT, IHI, and the RCSA of paraspinal muscles respectively. Patients were divided into three groups according to the severity of FJOA graded by the Weishaupt classification: grade 0 and grade 1 were group A, grade 2 were group B, and grade 3 were group C. All variables were compared among the three groups, while the relationship between parameters and grades of FJOA were also analyzed.

RESULTS

A total of 122 patients were included. PI was significantly greater in group C compared to group A (p = 0.025) and group B (p=0.022). FT was significantly greater in group C compared to group A (p<.001) and group B (p<.001). The RCSA of multifidus in group A were significantly greater than that in group B (p=0.02) and C (p=0.002). Additionally, FO in group C were significantly lower than group A (p<.001) and group B (p=0.028). The IHI in group C was significantly lower than group A (p=0.017). The correlation analysis indicated that grades of FJOA was positively related to Age, BMI (body mass index), PI, LL and FT, while negatively related to IHI, FO, RCSA of multifidus and RCSA of psoas major. Furthermore, the logistics regression showed that FT, PI, and IHI were important influence factors for FJOA.

CONCLUSIONS

The current study confirmed that FT, PI and IHI were significantly associated with grades of FJOA at L4-5. Additionally, longitudinal studies are needed to understand the causal relationship between these parameters and FJOA.

Correlation of clinical signs and magnetic resonance imaging findings in patients with lumbar spondylosis

Objectives

The purpose of the study was to contribute further to this debated topic by investigating the correlation of magnetic resonance imaging (MRI) findings with the clinical picture in lumbar spondylosis patients.

Patients and methods

This multicenter retrospective study (as part of the epidemiological project of the TLAR-OASG [Turkish League Against Rheumatism-Osteoarthritis Study Group]) included 514 patients (101 males, 413 females; mean age: 63.6±10.8 years; range, 40 to 85 years) who were diagnosed as lumbar spondylosis by clinical examination and direct X-ray between December 2016 and June 2018. Demographic characteristics of patients, Visual Analog Scale for pain, presence of radiating pain, Roland-Morris disability questionnaire, straight leg raise test, deep tendon reflexes, neurogenic intermittent claudication symptoms, any decrease of muscle strength, and abnormality of sensation were recorded. Lumbar MRI findings of the patients were recorded as positive or negative in terms of disc herniation, intervertebral disc degeneration, root compression, osteophytes, spinal stenosis. Statistical analysis was done to assess the correlation between the clinical symptoms, physical examination, and MRI findings.

Results

Correlation analysis of the MRI results and the clinical findings showed a significant correlation between straight leg raise test and root compression (p<0.001, r=0.328) and a significant correlation between neurogenic intermittent claudication and spinal stenosis (p<0.001, r=0.376). Roland-Morris disability questionnaire had a significant correlation with all MRI findings (p<0.05, r<0.200).

Conclusion

The results of this study corroborate the notion that diligent patient history and physical examination are more valuable than MRI findings, even though a higher incidence of abnormal MRI findings have been obtained in patients with disability and dermatomal radiating pain.

Amniotic membrane and/or umbilical cord tissue for treatment of facet joint syndrome: a narrative review

Musculoskeletal spine disorders, especially low back pain, induce enormous amounts of stress and financial burden on individuals and healthcare systems throughout the world. Disorders of the facet joints in the lumbar spine are the most predominant cause of back pain, resulting in facet joint syndrome (FJS). Conventional treatments for FJS are short-lived and have limitations and side effects. Thus, safer and more effective alternatives that can reduce pain and improve patient-reported outcomes are needed. Recently, the utilization of biologics, including the ones derived from perinatal tissue such as amniotic membrane (AM) and umbilical cord (UC), has significantly increased for regenerative medicine applications. This manuscript summarizes the outcomes of preclinical and clinical studies utilizing AM and/or UC for FJS. We identified no preclinical studies and 3 retrospective studies utilizing the search terms "amniotic membrane" and/or "umbilical cord" and "facet joint syndrome". The administration of AM + UC is safe and potentially efficacious for patients with FJS. However, more preclinical studies and appropriately powered, multi-center, prospective non-randomized and randomized controlled studies with longer follow-up are warranted to further evaluate the efficacy of AM + UC to justify its clinical use.

Anatomical and imaging measurements of the angle between the axis of the lumbar pedicle and lateral isthmus margin and its clinical significance

BACKGROUND

This study aims to explore the measurement of the angle between the axis of the pedicle and the lateral margin of the isthmus on the lumbar spine, and investigate its clinical significance.

METHODS

The angle was measured on 120 normal adults' X-ray and 25 dry anatomical specimens. 60 screws were placed by junior residents on 6 wet specimens through the freehand technique. 30 screws were placed on one side with their original experience. After learning the techniques mentioned in the study, 30 screws were placed on the other side. The specimens were examined by X-ray and CT, and the angles of the screw paths and the integrity of the pedicle were evaluated.

RESULTS

The angles of 120 subjects and 25 anatomical specimens show a gradually increasing trend. The differences among each segment were statistically significant (P < 0.05), but the difference in the same segment between the X-ray and the anatomical specimens was not statistically significant (P > 0.05). Furthermore, the differences in L1, L2, and L3 between the two genders were not statistically significant (P > 0.05). However, the angles were larger in female group than in male group in L4 and L5, and the differences were statistically significant (P < 0.05). The difference in the deviation rate of screw placement before and after the learning was statistically significant only in the L5 segment (P < 0.05). The difference in overall excellence rate was statistically significant (P < 0.05).

CONCLUSIONS

The measurement of the angle between the axis of the pedicle and the lateral margin of the isthmus on the lumbar can improve the accuracy of the lumbar sagittal screw angle.

Radiographic involvement of cervical facet joints in ankylosing spondylitis: a longitudinal analysis in correlation with vertebral body lesions

BACKGROUND

The inability to assess structural changes in facet joints is a limitation of established radiographic scoring systems for ankylosing spondylitis (AS). We compared radiographic evidence of ankylosis in cervical facet joints and cervical vertebral bodies in patients with AS.

METHODS

We analysed longitudinal data collected from 1106 AS patients and assessed 4984 spinal radiographs obtained up to 16 years of follow-up. Comparisons between cervical facet joints and cervical vertebral bodies focused on the presence of ankylosis, which was defined by at least one facet joint exhibiting complete ankylosis (according to the method of de Vlam) or at least one vertebral body with a bridging syndesmophyte (according to the modified Stoke Ankylosing Spondylitis Spinal Score [mSASSS]). Ankylosis was assessed over time using spinal radiographs collected during follow-up periods stratified in 4-year increments.

RESULTS

Patients with cervical facet joint ankylosis had higher cervical mSASSS, sacroiliitis grades, and inflammatory markers, with more prevalent hip involvement and uveitis. Overall, the numbers of spinal radiographs indicating ankylosis were comparable between cervical facet joints (17.8%) and cervical vertebral bodies (16.8%), and they usually presented together (13.5%). We observed similar proportions of radiographs with ankylosis only in cervical facet joints (4.3%) and cervical vertebral bodies (3.3%). As damage progressed, configurations with both cervical facet joint ankylosis and bridging syndesmophytes became more predominant with longer follow-up times, while configurations with cervical facet joint ankylosis only or bridging syndesmophytes only were less frequently observed.

CONCLUSIONS

Evidence of cervical facet joint ankylosis appears as often as bridging syndesmophytes on routine AS spinal radiographs. Presence of cervical facet joint ankylosis should be considered because it may have a higher disease burden.

MRI-based degeneration grades for lumbar facet joints do not correlate with cartilage mechanics

Background

Lumbar facet joint arthritis is characterized by degeneration of articular cartilage, loss of joint spacing, and increased boney spur formation. These signs of facet joint degeneration have been previously measured using destructive biochemical and mechanical analysis. Nondestructive clinical evaluation of the facet joint has also been performed using MRI scoring, which ranks the health of the facet joint using the Fujiwara scale. However, nondestructive clinical evaluation of facet joint arthritis using standard MRI scoring provides low resolution images which result in high interobserver variability. Therefore, to assess the accuracy of nondestructive MRI analysis with regard to the health of the facet joint, this study determined whether any correlations existed between lumbar facet joint articular cartilage mechanics, facet articular cartilage biochemical signatures, and Fujiwara scores.

Materials and Method

To accomplish this aim, human cadaveric lumbar spines were obtained and imaged using T1 MRI, then independently scored by three spine researchers. An osteochondral plug from each of the L2 thru L5 facet joints was obtained and loaded under unconfined compression.

Results

The experiments showed no trends between histological images and changes in the Fujiwara score. The mechanical properties of articular cartilage (thickness, Young's modulus, instantaneous modulus, and permeability) also had no correlations with the Fujiwara score.

Conclusions

These results show that the current Fujiwara score cannot accurately describe the biomechanics or biochemical composition of facet joint articular cartilage.

Facet Joint Orientation/Tropism Could Be Associated with Fatty Infiltration in the Lumbar Paraspinal Muscles

BACKGROUND

Facet joint orientation (FJO) and facet joint tropism (FJT) are associated with intervertebral disc degeneration and paraspinal muscle atrophy. However, none of the previous studies has evaluated the association of FJO/FJT with fatty infiltration in the multifidus, erector spinae, and psoas muscles at all lumbar levels. In the present study, we aimed to analyze whether FJO and FJT were associated with fatty infiltration in the paraspinal muscles at any lumbar level.

METHODS

Paraspinal muscles and FJO/FJT were evaluated from L1-L2 to L5-S1 intervertebral disc levels on T2-weighted axial lumbar spine magnetic resonance imaging.

RESULTS

Facet joints were more sagittally and coronally oriented at the upper and lower lumbar levels, respectively. FJT was more obvious at lower lumbar levels. The FJT/FJO ratio was higher at upper lumbar levels. Patients with sagittally oriented facet joints at the L3-L4 and L4-L5 levels had fattier erector spinae and psoas muscles at the L4-L5 level. Patients with increased FJT at upper lumbar levels had fattier erector spinae and multifidus at lower lumbar levels. Patients with increased FJT at the L4-L5 level had less fatty infiltration in the erector spinae and psoas at the L2-L3 and L5-S1 levels, respectively.

CONCLUSIONS

Sagittally oriented facet joints at lower lumbar levels could be associated with fattier erector spinae and psoas muscles at lower lumbar levels. The erector spinae at upper lumbar levels and psoas at lower lumbar levels might have become more active to compensate the FJT-induced instability at lower lumbar levels.

The Impact of Spinopelvic Alignment on the Facet Joint Degeneration

STUDY DESIGN

Retrospective Cohort.

OBJECTIVES

This study aims to evaluate the relations between facet joint degeneration (FD) and sagittal spinopelvic parameters. Second, the association of FD with degenerative disc disease (DDD) and lumbar disc herniations (LDH) was assessed.

METHODS

The radiologic data of 192 patients was retrospectively analyzed. Total, proximal, and distal lumbar lordosis (LL, PLL, and DLL), pelvic incidence (PI), pelvic tilt (PT), sacral slope (SS), and sacral table angle (STA) were measured on lumbar x-ray plates. DDD and FD was graded on the MRI images. The apex of lumbar lordosis and PI-LL imbalance were noted in each patient. Correlation analyses were performed.

RESULTS

Age and body mass index (BMI) were correlated with FD. LL and DLL are positively associated with upper-level FDs (L1-2 and L2-3) (P < 0,05). PLL were positively associated with lower level FD (L5-S1) (P < 0,05). A significant increase in PI was associated with FD in L2-3 and L4-5. A larger PT was found in FD in L4. The PI-LL imbalance was not correlated with the FD. Correlation between DDD and LDH and FD was observed in each level (P < 0,01). The level of FD is not affected by the apex of the curve.

CONCLUSION

Age and BMI have a direct impact on FD. However, spinopelvic parameters influence the severity of FD rather than its occurrence. In addition to the effects of lumbar lordosis as a single entity, it is essential to consider separately the effects of proximal and distal lumbar lordosis at the FD level.

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

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

An overview of lumbar anatomy with an emphasis on unilateral biportal endoscopic techniques: A review

Unilateral biportal endoscopy (UBE) is a major surgical technique used to treat degenerative lumbar diseases. The UBE technique has the advantages of flexible operation, high efficiency, and a large observation and operation space. However, as a typical representative of minimally invasive techniques, UBE still needs to complete a wide range of decompression and tissue resection in a narrow working space, resulting in many surgery-associated injuries. Therefore, it is necessary to reduce complications by familiarity with the anatomy of the lumbar spine. Based on the UBE technique, this review article provides historical and current information on the anatomical structures of the lumbar vertebrae, such as the articular process, pedicle, lamina, ligamentum flavum, nerve root, intervertebral disc, and artery supply.

Creation and validation of a predictive model for lumbar synovial cyst recurrence following decompression without fusion

OBJECTIVE

Lumbar synovial cysts (LSCs) represent a relatively rare clinical pathology that may result in radiculopathy or neurogenic claudication. Because of the potential for recurrence of these cysts, some authors advocate for segmental fusion, as opposed to decompression alone, as a way to eliminate the risk for recurrence. The objective of this study was to create a predictive score for synovial cyst recurrence following decompression without fusion.

METHODS

A retrospective chart review was completed of all patients evaluated at a single center over 20 years who were found to have symptomatic LSCs requiring intervention. Only patients undergoing decompression without fusion were included in the analysis. Following this review, baseline characteristics were obtained as well as radiological information. A machine learning method (risk-calibrated supersparse linear integer model) was then used to create a risk stratification score to identify patients at high risk for symptomatic cyst recurrence requiring repeat surgical intervention. Following the creation of this model, a fivefold cross-validation was completed.

RESULTS

In total, 89 patients were identified who had complete radiological information. Of these 89 patients, 11 developed cyst recurrence requiring reoperation. The Lumbar Synovial Cyst Score was then created with an area under the curve of 0.83 and calibration error of 11.0%. Factors predictive of recurrence were found to include facet inclination angle > 45°, canal stenosis > 50%, T2 joint space hyperintensity, and presence of grade I spondylolisthesis. The probability of cyst recurrence ranged from < 5% for a score of 2 or less to > 88% for a score of 7.

CONCLUSIONS

The Lumbar Synovial Cyst Score model is a quick and accurate tool to assist in clinical decision-making in the treatment of LSCs.

Facet overhang: A novel parameter in the pathophysiology of multifidus muscle atrophy

The relationship between degenerative zygapophysial joint (facet) arthropathy and multifidus muscle atrophy has not been rigorously evaluated. The purpose of this study was to determine if specific morphological features of degenerative facet arthropathy are correlated with multifidus muscle atrophy. We retrospectively reviewed medical records and imaging studies of patients with lumbar spinal stenosis. Facet overhang, bridging osteophyte formation, facet effusion, and facet angles were evaluated by univariable and multivariable regression to identify independent associations with deep and superficial parts of the multifidus total cross-sectional area (tCSA), functional cross-sectional area (fnCSA), and fatty infiltration (FI). Facet overhang was classified as severe in 50 females (53.2%) versus 56 males (36.9%) (p = 0.030). Severity of facet overhang and female sex were independently associated with smaller deep part of the multifidus tCSA and fnCSA as well as higher FI, reflecting greater atrophy of the deep region compared to total muscle mass. In comparison, severe facet overhang (p < 0.001; OR = 3.47, 95% CI = 2.13-5.66) and female sex (p < 0.001; OR = 4.19, 95% CI = 2.58-6.79) were independently associated only with higher superficial part of the multifidus FI, reflecting muscle steatosis without significant lean muscle atrophy. In patients with degenerative lumbar spinal stenosis, facet overhang is an independent risk factor for deep part of the multifidus atrophy. Bridging osteophyte formation, facet effusion, and facet angles were not independently associated with deep part of the multifidus atrophy.

Influence of the facet joint angle on facet joint degeneration following pedicle screw fixation without fusion in thoracolumbar fractures

BACKGROUND

Posterior approach pedicle screw fixation without fusion is widely used in the treatment of neurologically intact type A3 thoracolumbar fractures.

OBJECTIVE

To analyze the influence of the facet joint (FJ) angle on FJ degeneration following posterior approach pedicle screw fixation without fusion in neurologically intact type A3 thoracolumbar fractures.

METHODS

Fifty-eight patients who underwent pedicle screw fixation via the traditional posterior approach (n= 28) or the Wiltse approach (n= 30) were enrolled. A CT scan was performed before fixation and before fixation removal (Within 1.5 to 2 years after fixation) to evaluate the FJs parameters, including FJ inclination (FJI), FJ tropism (FJT), FJ violation, and FJ degeneration grade (FJDG), of three fixed segments and the adjacent segment below the fixed segments.

RESULTS

There was no significant difference in FJ violation rate, FJDG deterioration, or FJ angle between the two groups (P> 0.05). FJDG deterioration showed a weak positive correlation with FJI and FJT before fixation, and the angular change in FJI (P< 0.05); and FJT before fixation and the angular change in FJI were risk factors for FJDG deterioration (P< 0.01).

CONCLUSION

The Wiltse approach did not increase the rate of FJDG deterioration and FJs angle changes. However, the FJT before fixation and the angular change in FJI were risk factors for FJDG deterioration.

A Systematic Review and Meta-Analysis of the Facet Joint Orientation and Its Effect on the Lumbar

Facet tropism is recognized as the difference in the positioning of the facet joints in association with each other in the sagittal plane. This guides to an imbalanced biomechanical force over the facet joints and the intervertebral disc during rotation and other physiological activities. A systematic review and meta-analysis of Web of Science, EMBASE, PubMed, Cochrane Library, SCOPUS, and CINHAL from 2004 to 2021 to recognize the related research studies was performed. The data for meta-analysis were obtained from multiple studies to get the combined effect of the facet tropism on the lumbar disc herniation (LDH) and the degenerative lumbar spondylolisthesis (LDS). 117 articles were incorporated in the systematic review, where 41 studies were selected for meta-analysis, out of which 7 studies were found eligible as per the inclusion criteria. When degenerative lumbar spondylolisthesis was compared with the normal group, 95% CI was observed at 1.94 (1.59, 2.28). There was a comparison of disc herniation with the normal group in L4/L5, with a 95% CI of 0.60 (0.05, 1.14). The L5/S1 disc herniation was compared with the normal group and was found to be 0.21 (-0.48, 0.90). Therefore, it was observed that facet tropism is related to lumbar disc herniation and degenerative lumbar spondylolisthesis. Our meta-analysis demonstrated a unique link between the facet tropism and the lumbar disk degeneration along with degenerative lumbar spondylolisthesis.

CT guided minimal invasive oxygen ozone therapy in patients with degenerative changes of lumbosacral spine

Degenerative spine conditions involve the gradual loss of normal structure and function of spine over time. They are usually caused by aging, but may also be the result of tumors, infections or arthritis. Pressure on the spinal cord and nerve roots caused by degeneration can be caused by herniated discs. Degenerative disc disease is one of the most common causes of low back and neck pain, and also one of the most misunderstood ones. Low back pain (LBP) is a common disorder affecting an increasing number of people worldwide, whose diagnosis is focused on the identification of triggering causes. First line therapy usually starts from conservative approaches, whereas second line treatments include a spectrum of minimally invasive techniques, before resorting to more invasive surgical approaches. Among minimally invasive techniques, percutaneous oxygen-ozone injections represent one of the most common and cost-effective procedures. Oxygen-ozone therapy is a minimally invasive treatment for lumbar disc herniation that uses the biochemical properties of the gas mixture of oxygen and ozone. Intradiscal, periradicular or intraarticular ozone therapy is used in patients that do not respond to standard conservative therapies for low back pain due to degenerative disc-induced lumbar disc herniation (LDH) or other degenerative process of nearby structures such as zygapophyseal articulations. All the interventional procedures for low back pain may be guided by ultrasound, computerized tomography or fluoroscopy.

Associations between facet tropism and vertebral rotation in patients with degenerative lumbar disease

Background

Vertebral rotation and facet tropism are very common in various lumbar degenerative diseases. Facet tropism means the presence of asymmetric angles on both sides of the facet joints. Studies have shown that facet tropism contributes to lumbar degenerative disease, and also inevitably leads to the asymmetry of movement and the imbalance of force, which may be possible to rotate the vertebral body. The aim of this study was to explore the correlation between lumbar vertebral rotation and facet tropism in patients with lumbar degenerative diseases.

Methods

A total of 198 patients with lumbar degenerative diseases from 2018 to 2019 were enrolled. Five hundred and seventy vertebral rotation angles and 1140 facet angles were measured. The vertebral bodies are divided into non-rotation group (Group A) and rotation group (Group B) with the vertebral rotation angle of 3° as the boundary. The information including gender, age, BMI (body mass index), bone mineral density, history of smoking, drinking, hypertension, diabetes, diagnosis, segment distribution, and degree of facet degeneration were also counted. Using inter-class correlation coefficients (ICC) to test the reliability of measurement results. Univariate and multivariate logistic regression analysis were used to analyze the relationship between vertebral rotation and facet tropism.

Results

The consistency of the ICC within the groups of the observers is above 0.8, with good agreement. The results of univariate analysis showed that facet tropism was significantly different between group A and group B (OR (odds ratio)  = 3.30, 95% CI  =  2.03–5.35, P  < 0.0001). Other significant factors were included as adjustment variables into the multivariate regression model. Three models were analyzed separately (Model 1: non-adjusted. Model 2: adjust for age; facet degeneration; Model 3: adjust for age; disease distribution; segment distribution; facet degeneration). The results showed that after adjusting the confounders, the correlation between facet tropism and vertebral rotation did not change (Model 1: OR  = 3.30, 95% CI  = 2.03–5.35, P  < 0.0001; Model 2: adjusted OR  = 2.87, 95% CI  = 1.66–4.97, P  = 0.0002, Model 3: adjusted OR  = 2.84, 95% CI  = 1.56–5.17, P  = 0.0006).

Conclusion

Current research demonstrates that there is an association between vertebral rotation and facet tropism, suggesting that vertebral rotation may also have a certain degree of correlation with lumbar degenerative diseases.

Facet syndrome. Minimally invasive surgical treatment. Clinical case with a literature review

Background: Degenerative pathology of the facet joints of the lumbar spine remains a significant medical and social problem due to persistent pain syndrome, high incidence and disability rate. Clinical case description: A patient complaining of pain and discomfort in the lumbosacral spine on the right, arising in the upright position, intensifying with bending and flexion-extension of the trunk, and periodically spreading to the right gluteal region and along the posterior surface of the thigh, was admitted to the neurosurgical department of the Irkutsk Scientific Center of Surgery and Traumatology. A surgical treatment was performed in the form of dereception of the LIILIII, LIIILIV, LIVLV arch-process joints. In the postoperative period, the patient noted a decrease in the intensity of pain in the lumbosacral spine to 3 points by a visual analog scale and was discharged from the department on the 5th day after the surgery in a satisfactory condition. Conclusion: Facet joint pathologies represent a most common nosological form of the degenerative-dystrophic process (spondyloarthrosis) and a potential source of pain with the formation of instability of the spinal motion segment and chronic pain syndrome. The complex anatomical and topographic relationships between the facet joints, intervertebral discs, and radicular nerves force clinicians to pay attention to the pathology of facet syndrome. Understanding the morphological, clinical, and radiological features of the course of the facet joint degeneration makes it possible to increase the diagnostic capabilities for detecting facet syndrome of the lumbar spine and effectively apply transcutaneous surgical technologies for the treatment of chronic pain syndromes.

The biomechanical effect of the relevant segments after facet-disectomy in different diameters under posterior lumbar percutaneous endoscopes: a three-dimensional finite element analysis

OBJECTIVE

To evaluate the biomechanical influence after percutaneous endoscopic lumbar facetectomy in different diameters on segmental range of motion (ROM) and intradiscal pressure (IDP) of the relevant segments by establishing three dimensional finite element (FE) model.

METHODS

An intact L3-5 model was successfully constructed from the CT of a healthy volunteer as Model A (MA). The Model B (MB), Model C (MC) and Model D (MD) were obtained through facetectomy on L4 inferior facet in diameters 7.5 mm, 10 mm and 15 mm on MA for simulation. The ROM and IDP of L3/4 and L4/5 of four models were all compared in forward flexion, backward extension, left and right bending, left and right rotation.

RESULTS

Compared with MA, the ROM of L4/5 of MB, MC and MD all increased. MD changed more significantly than MB and MC in backward extension, right bending and right rotation. But that of MB and MC on L3/4 had no prominent change, while MD had a slight increase in backward extension. The IDP of MB and MC on L4/5 in six states was similar to MA, yet MD increased obviously in backward extension, right bending, left and right rotation. The IDP on L3/4 of MB and MC was resemble to MA in six conditions, nevertheless MD increased slightly only in backward extension.

CONCLUSION

Compared with the facetectomy in diameters 7.5 mm and 10 mm, the mechanical effect brought by facetectomy in diameter 15 mm on the operating segment changed more significantly, and had a corresponding effect on the adjacent segments.

Wnt16 protects chondrocytes from lumbar facet joint osteoarthritis through the Wnt/β-catenin pathway in low back pain patients

PURPOSE

Low back pain (LBP) is a long-lasting and chronic symptom without any exact cause. This study attempts to propose a new staging system based on the original grading system combined with pathological results and clinical symptoms to better clarify the dynamic evolution of LBP related to cartilage degeneration during facet joint osteoarthritis (FJOA). To explore a potential target for diagnosis, treatment, and drug intervention of facet joint osteoarthritis related LBP via protecting chondrocytes.

MATERIALS AND METHODS

All the facet joints were divided into 4 groups according to our new degenerative staging system based on Weishaupt grade, CT and MRI. Collect the facet joint samples from patients whom suffered lumbar fusion surgery for lumbar disc herniation. Molecular biology experiments were used to explore the effect of Wnt16 on the degeneration of facet joints. Micro-CT examination and pain stimulation test checked the biological function of Wnt16 in rats.

RESULTS

Wnt16 was significantly increased and more aggregated in the facet joint chondrocytes in the Phase III and Phase IV, which is consistent with the pathological findings of cartilage degeneration (OARSI). We found that Wnt16 participated in the regulation of FJOA via Wnt/β-catenin pathway in vitro, which was inhibited by specific inhibitor DKK1. The rats, rich expressed Wnt16, showed higher paw withdrawal thresholds and prolonged paw withdrawal latency to FJOA related LBP. Micro-CT examination for the lumbar spine of rats showed Wnt16 protected the chondrocytes from FJOA.

CONCLUSIONS

This study defined a new staging system for LBP related cartilage degeneration of facet joint based on the original grading system combined with pathological results and clinical symptoms. Wnt16 is expected to be a potential target for treatment of FJOA via protecting chondrocytes.

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

STUDY DESIGN

Longitudinal cohort study with 13-year follow-up.

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Morphology and growth of the pediatric lumbar vertebrae

BACKGROUND CONTEXT

The majority of existing literature describing pediatric lumbar vertebral morphology are limited to characterization of the vertebral bodies, pedicles, and spinal canal and no study has described the rates of growth for any lumbar vertebral structure. While it is known that growth of the lumbar vertebrae results in changes in vertebral shape, the dimension ratios used to quantify these shape changes do not represent the 3D morphology of the vertebral structures. Additionally, many of the previous evaluations of growth and shape are purely descriptive and do not investigate sexual dimorphism or variations across vertebral levels.

PURPOSE

This study aims to establish a database of pediatric lumbar vertebra dimension, growth, and shape data for subjects between and ages of 1 and 19 years.

STUDY DESIGN

A retrospective study of computed tomography (CT) data.

METHODS

Retrospective, abdominal, CT scans of 102 skeletally normal pediatric subjects (54 males, 48 females) between the ages of 1 and 19 years were digitally reconstructed and manually segmented. Thirty surface landmark points (LMPs), 30 vertebral measurements, the centroid size, centroid location, and the local orientation were collected for each lumbar vertebra along with the centroid size of the LMPs comprising each subject's full lumbar spine and their intervertebral disc (IVD) heights. Nonparametric statistics were used to compare dimension values across vertebral levels and between sexes. Linear models with age as the independent variable were used to characterize dimension growth for each sex and vertebral level. Age-dependent quadratic equations were fit to LMP distributions resulting from a generalized Procrustes analysis (GPA) of the vertebrae and fixed effects models were used to investigate differences in model coefficients across levels and between sexes.

RESULTS

Intervertebral level dimension differences were observed across all vertebral structures in both sexes while pedicle widths and IVDs heights were the only measurements found to be sexually dimorphic. Dimension growth rates generally varied across vertebral levels and the growth rates of males were typically larger than those of females. Differences between male and female vertebral shapes were also found for all lumbar vertebral structures.

CONCLUSIONS

To the authors' knowledge, this is the first study to report growth rates for the majority of pediatric lumbar vertebral structures and the first to describe the 3D age-dependent shapes of the pediatric lumbar spine and vertebrae. In addition to providing a quantitative database, the dimension, growth, and shape data reported here would have applications in medical device design, surgical planning, surgical training, and biomechanical modeling.

Sources of lumbar back pain during aging and potential therapeutic targets

Lumbar back pain during aging is a major clinical problem, the origins and underlying mechanisms of which are challenging to study. Degenerative changes occur in various parts of the functional spinal unit, such the vertebral endplate and intervertebral disc. The homeostasis of these structural components is regulated by signaling molecules, such as transforming growth factor-β and parathyroid hormone. Previous efforts to understand sources of lumbar back pain focused on sensory innervation in the degenerative intervertebral disc, but intervertebral disc degeneration is frequently asymptomatic. An in vivo mouse model of lumbar spine aging and degeneration, combined with genetic technology, has identified endplate innervation as a major source of lumbar back pain and a potential therapeutic target. In this review, we consider how each structural component of the functional spinal unit contributes to lumbar back pain, how the homeostasis of each component is regulated, and how these findings can be used to develop potential therapies.

FACET JOINT DEGENERATION IN PATIENTS WITH LUMBAR DISC HERNIATION AND PROBABLE DETERMINING FACTORS

ABSTRACT Objective To evaluate facet joint degeneration following surgical treatment in patients with lumbar disc herniation, seeking to correlate it with possible determining factors. Methods Cross-sectional observational study, which analyzed medical records, radiographs and magnetic resonance images of 287 patients with lumbar disc herniation treated surgically at the Spine Surgery Service of the Hospital Ortopédico de Passo Fundo. Information about age and sex was collected. In the imaging exams, the following variables were evaluated: facet joint angulation and its tropism, measured by the Karacan method, sacral slope and lumbar lordosis, measured by the Cobb method, arthrosis of the interfacetary joints, measured by the Weishaupt classification, and intervertebral disc degeneration, measured by the Pfirrmann classification. Results A statistically significant relationship was observed between facet joint degeneration and age (p = 0.002), and also between facet joint degeneration and sacral slope (p = 0.038). No correlation was found between facet joint degeneration and lumbar lordosis (p = 0.934). It was found that the most degenerated facet joints were those that had the greatest facet joint asymmetry (tropism). However, the mean degree of facet tropism did not increase homogeneously with the progression of the joint degeneration score (p = 0.380). Conclusion It was verified that there are, in fact, a multiplicity of factors related to the degree of facet joint degeneration in the low lumbar spine. Additional studies, correlated with the asymmetry of the facet joints, would be important to elucidate better preventive management of this degeneration, aiming to avert secondary low back pain and sciatica with advancing age. Level of evidence II; Retrospective study.

One-Stage Posterior Only Corpectomy and Fusion in the Treatment of a Unique Acute Low Lumbar L4 Burst Fracture Without Neurologic Deficit: A Case Presentation

L4 and L5 fractures are different from those at the thoracolumbar area. These differences include anatomy, biomechanics, classification, and treatment possibilities. Given the accessible literature and lack of high-quality information about the management of low lumbar fractures, we describe the case of a young 26-year-old male was referred to our emergency medical center with a severe L4 vertebral body comminuted burst fracture with complete spinal canal compression (AO type 4). Incredible, all neurological functions were intact initially. The patient was cured through a one-stage posterior only vertebrectomy and fusion with preservation of all neurological functions. Clinical and radiologic follow-up was satisfactory after 2 years. In more severe lumbar injuries, decisions contain spinal decompression and stabilization through a posterior or anterior approach based on the surgeon's favorite. In our experience in this patient, a posterior approach only was used both for decompression and stabilization without routine challenging existing in anterior approaches.

Comparison of Decompression versus Decompression and Fusion for Lumbar Synovial Cysts and Predictive Factors for Cyst Recurrence

BACKGROUND

The management of lumbar synovial cysts (LSC) has been a controversial topic for many years. Whereas many authors label LSC as markers of instability and thus necessitating fusion, others suggest that decompression alone without fusion is a viable initial treatment option. Our objective was to clarify outcomes in patients undergoing decompression alone and decompression with fusion for symptomatic LSC and identify factors for cyst recurrence.

METHODS

A retrospective case series was performed of all patients undergoing initial treatment for LSC at a single institution ranging from January 1999 to February 2020. Surgical treatment included either decompression with cystectomy or decompression with cystectomy and a fusion procedure. Preoperative symptoms were collected and included radicular pain, motor deficits, sensory deficits, or bowel/bladder changes. Radiographic data were calculated individually and confirmed with radiology reports. Categorical variables were assessed using χ² analysis and continuous variables were assessed with the 2-sample t test.

RESULTS

In total, 161 patients were identified as presenting with symptomatic LSC. Of these, 104 patients underwent decompression alone versus 57 who underwent decompression and fusion. In the decompression group 11 patients required reoperation at the level of the cyst compared with none in those undergoing fusion as their initial procedure (10.5% vs. 0%, P = 0.012). On subgroup analysis of those undergoing decompression as their initial procedure, patients with cyst recurrence demonstrated a statistically significant greater coronal facet inclination angle compared with those without cyst recurrence (52.4° vs. 40.6°, P = 0.02).

CONCLUSIONS

Decompression alone is a reasonable choice for the initial management of LSC, although it does carry a significant risk of same-level reoperation due to cyst recurrence and spondylolisthesis. Preoperative coronal facet inclination angle may be a useful measurement in predicting cyst recurrence following decompression.

Development of a novel rat model of lumbar facet joint osteoarthritis induced by persistent compressive injury

The aim of the present study was to develop a novel animal model of lumbar facet joint osteoarthritis induced by persistent compressive injury. An intraspinal compression spring was randomly implanted into either the L4/5 or the L5/6 spinal segments of 40 Sprague Dawley (SD) rats to induce compression. Sham-operations were used in the other segment of the same rats as the control levels. The animals were sacrificed at 7, 14, 28, 42 and 56 days after surgery, prior to the radiological confirmation of the spring location. Degeneration of the lumbar facet joints was evaluated by macroscopic observation in addition to histological and immunohistological analyses. The results of this present study revealed the absence of spring dislocation during the entire observation period. Macroscopic and Osteoarthritis Research Society International scores of the compression levels were found to be higher in the compression levels compared with those noted in the control levels (P<0.05). In addition, interleukin-1β and tumor necrosis factor-α expression in the compression levels were increased over time compared with those recorded in the control levels. In conclusion, persistent compressive injury may induce degeneration of the lumbar facet joint. This novel animal model could serve as a useful tool for further studies into the mechanisms of action and potential treatment of lumbar facet joint osteoarthritis.

Relationship Between Endplate Defects, Modic Change, Facet Joint Degeneration, and Disc Degeneration of Cervical Spine

Objective

The “disc degeneration precedes facet joint osteoarthritis” hypothesis and multidimensional analysis were actively discussed in lumbar spine. However, in cervical spine degeneration, the multifactorial analyzes of disc degeneration (DD), Modic changes (Mcs), facet degeneration, and endplate degeneration (ED) is still limited. In this cross-sectional study, we aimed to analyze the prevalence and interrelationship of cervical DD parameters.

Methods

We retrospectively recruited 62 patients aged between 60 and 70 years. The disc height, segmental angle, ossified posterior longitudinal ligament (OPLL), ED, facet joint degeneration (FD), uncovertebral joint degeneration (UD), DD, spinal stenosis (SS), Mc, and cord signal change (CS) were evaluated using a previously well-known grading system.

Results

The prevalence of cervical degenerative parameters were DD (grade 1, 1.2%; grade 2, 13.3%; grade 3, 54.8%; grade 4, 19.0%; grade 5, 11.7%), OPLL (26.2%), SS (grade 0, 7.7%; grade 1, 42.3%; grade 2, 26.2%; grade 3, 23.8%), UD (39.1%), ED (normal, 69.0%; focal defect, 9.7%; corner defect, 11.7%; erosion, 6.9%; sclerosis, 2.8%), and FD (normal, 48.8%; narrowing, 27.0%; hypertrophied, 24.2%). The interrelationship of degenerative parameters showed close relation between UD, SS, DD, OPLL, Mc. ED, and CS has partial relation with degenerative finding. FD only has relation with UD, and Mc.

Conclusion

Our results may indicate that FD is a degeneration that occurs independently, rather than as a result of other degenerative factors.

Facet Tropism and Orientation: Risk Factors for Degenerative Lumbar Spinal Stenosis

The aim of this study is to establish whether facet tropism (FT) and orientation (FO) are associated with degenerative lumbar spinal stenosis (DLSS). A retrospective computerized tomography (CT) study including 274 individuals was divided into two groups: control (82 males and 81 females) and stenosis (59 males and 52 females). All participants have undergone high-resolution CT scan of the lumbar spine in the same position. FT and FO were measured at L1-2 to L5-S1. Significant sagittal FO was noted in the stenosis males (L2-3 to L4-5) and females (L2-3 to L5-S1) compared to the controls. The prevalence of FT was remarkably greater in the stenosis males (L4-5, L5-S1) and females (L3-4, L5-S1) compared to their counterparts in the control group. Our results also showed that FT (L3-4 to L5-S1) increases approximately 2.9 times the likelihood for DLSS development. This study indicates that FO and FT in the lower lumbar spine are significantly associated with DLSS.

The impact and distinction of 'lipid healthy but obese' and 'lipid abnormal but not obese' phenotypes on lumbar disc degeneration in Chinese

Background

Lipid abnormality and obesity have been proposed to be associated with lumbar disc degeneration, but little is known about the effect of ‘lipid healthy but obese’ (LH-O) and ‘lipid abnormal but not obese’ (LA-NO) phenotypes on lumbar disc degeneration in Chinese. The study aims to determine the impact and distinction of LH-O and LA-NO phenotypes on lumbar disc degeneration in Chinese, and to identify the association of related factors with risk of lumbar disc degeneration.

Methods

A total of 678 individuals were included with lumbar magnetic resonance imaging, serum lipid levels and anthropometric measurements. Obesity was defined on the basis of body mass index or waist to hip ratio (WHR). Pfirrmann score and Weishaupt’s scale were utilized to assess the degree of disc degeneration and facet joint degeneration.

Results

The incidence of the LH-O and LA-NO phenotypes were 11.4% and 18.1%, respectively. LA-NO phenotype demonstrates a high incidence for disc degeneration (P < 0.05), while LH-O phenotype confers a severe disc degeneration grade (P < 0.05). No statistical difference in the percentage of severe facet joint degeneration grade in each group (P > 0.05). Elevated triglycerides and greater WHR may be the risk factors for lumbar disc degeneration in Chinese.

Conclusion

LH-O and LA-NO phenotypes are common with different status of disc degeneration in Chinese. Elevated triglycerides and abdominal obesity appear to play crucial roles in the development of lumbar disc degeneration.

Lumbar stability following graded unilateral and bilateral facetectomy: A finite element model study

BACKGROUND

Excision of excessive amount of facet joint during lumbar discectomy or decompression can cause segmental instability of the lumbar spine. This study was performed to assess the segmental instability, facet joint loading and intradiscal pressure following graded lumbar facetectomy. This biomechanical study was performed using a verified and validated L3-S1 finite element model.

METHODS

Nine scenarios were analysed. Intact model as control, 30%, 45%, 60% and complete facet joint excision in unilateral and bilateral setting. The effect of progressive graded facetectomy of L4-L5 on the segmental mobility, facet loading and intradiscal pressure was assessed.

FINDINGS

In comparison with control 30% excision of the facet joint mainly caused increase in mediolateral mobility. With 45% excision of the facet joint there was increase in both anteroposterior and mediolateral mobility, this was worse in bilateral and unilateral models respectively. This worsened with larger facet excision scenarios. Facet load increased significantly on extension with excision of 45% & 60% unilaterally and 100% bilaterally. Flexion produced rise in intradiscal pressure in all scenarios.

INTERPRETATION

The increased spinal mobility, facet loading and intradiscal pressure with more than 30% facetectomy highlights the importance of preserving the facets during decompression thereby safeguarding accelerated degeneration of these segments and iatrogenic segmental instability. The findings from this study could also potentially explain the correlation between spinal instability, disc degeneration and facet joint arthrosis as noted in clinical studies.

Lumbar facet joint subchondral bone density in low back pain and asymptomatic subjects

OBJECTIVE

To report in vivo measurements of lumbar facet joint subchondral bone mineral density used in the description of facet joint loading patterns and to interrogate if low back pain is associated with changes in subchondral bone mineral density.

MATERIALS AND METHODS

In vivo measurements of lumbar facet joint subchondral bone mineral density (L1/2 to L5/S1) in Hounsfield units were performed on 89 volunteers (56 controls and 33 with low back pain) by computed tomography osteoabsorptiometry at subchondral regions between 1.5 mm and 2.5 mm below the joint surface. The facet surface was divided into five topographic zones: cranial, lateral, caudal, medial, and central.

RESULTS

We analyzed 1780 facet joint surfaces. Facets were denser (p < 0.0001) both in superior facets and in low back pain subjects (p < 0.0001). For the entire cohort, the facet center zone subchondral bone mineral density was higher (p < 0.0001) than that of the peripheral zones. The analyses indicate that subchondral bone mineral density is highest in patients with low back pain, the superior facets, and the center zone of the facets.

CONCLUSIONS

Subchondral bone mineral density is thought to reflect cumulative, long-term distribution of stress acting on a joint. This work shows that higher subchondral bone mineral density values in the center zone indicate predominant stress transmission through the center of the facet joints. Finally, the greater subchondral bone mineral density in patients with low back pain may reflect both increased load bearing by the facets secondary to disc degeneration and misdistribution of loading within the joint.

Association Between Self-Reported Spinal Morning Stiffness and Radiographic Evidence of Lumbar Disk Degeneration in Participants of the Cohort Hip and Cohort Knee (CHECK) Study

BACKGROUND

Low back pain (LBP) is very common and is a main cause of limited activity and work absence. Patients with LBP may also report spinal morning stiffness; this symptom could be useful for identifying subgroups with signs and symptoms related to spinal osteoarthritis.

OBJECTIVE

This study investigated whether an association exists between reported spinal morning stiffness and radiographic evidence of lumbar disk degeneration (LDD) in people with LBP and a history of pain of the hip and/or knee.

DESIGN

This cross-sectional study used 8-year follow-up data from the Cohort Hip and Cohort Knee study.

METHODS

The association between spinal morning stiffness and radiographic LDD features was assessed with multivariable logistic regression models.

RESULTS

The presence of osteophytes was significantly associated with spinal morning stiffness (odds ratio [OR] = 2.1 [95% confidence interval [CI] = 1.3-3.2]) as was the presence of grade 2 or 3 disk space narrowing (OR = 2.0 [95% CI = 1.1-3.5]). There was also a significant association between morning stiffness persisting for > 30 minutes and grade 2 osteophytes (OR = 2.6 [95% CI = 1.1-6.2]) and grade 1 disk space narrowing (OR = 2.0 [95% CI = 1.1-3.6]). Furthermore, there was a significant association between moderate spinal morning stiffness and the presence of osteophytes (OR = 2.0 [95% CI = 1.2-3.2]). Both the presence of osteophytes and disk space narrowing were significantly associated with severe spinal morning stiffness (for osteophytes: OR = 2.0 [95% CI = 1.2-3.7]; for narrowing at L1-S1: OR = 1.8 [95% CI = 1.1-3.1]).

LIMITATIONS

Only lumbar lateral radiographs were available for each participant, implying that the LDD features could have been underestimated. The quality of the radiographs was not consistent.

CONCLUSIONS

This study showed an association between self-reported spinal morning stiffness and symptomatic LDD. When morning stiffness lasted > 30 minutes, there was a significant association with the features of LDD. The association was stronger when the severity of spinal morning stiffness increased.

Exploring the pathological role of intervertebral disc and facet joint in the development of degenerative scoliosis by biomechanical methods

BACKGROUND

To investigate the biomechanical changes in the development of scoliosis due to intervertebral disc and facet joint degeneration.

METHODS

We enrolled 39 cases of fresh-frozen lumbar spine specimens and underwent CT scanning and 3D reconstruction. An Osirix Dicom imaging system was to assess the degeneration of the intervertebral disc and facet joints, and mechanical loading was conducted using a spine mechanical instrument with the frequency set at plus/minus 7.5 NM, 0.005 Hz. Range of motion (ROM) and neutral zone (NZ) of 39 cadaveric lumbar spines were tested.

FINDINGS

Degeneration existed in all 39 cases of the lumbar specimens: the Cobb angle >10° in 5 cases (degenerative scoliosis (DS) group), between 3° and 10° in 9 cases (pre-degenerative scoliosis (PS) group) and <3° in 25 cases (no scoliosis (NS) group). The axial torsion (AT) range of motion (ROM_AT) and the NZ of the DS and PS groups was greater than in the NS group and increased with increasing Cobb angle. A significant correlation was found between the degeneration of the intervertebral disc and the AT and the AT correlated with the Cobb angle and facet joint degeneration.

INTERPRETATION

The AT correlated with intervertebral disc and facet joint degeneration, which might be a mechanic factor in the occurrence and development of degenerative scoliosis.

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

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

[Lumbar facet joint degeneration contributes to degenerative lumbar scoliosis induced by asymmetric stress in rabbits]

OBJECTIVE

To investigate the role of lumbar facet joint degeneration in the development of degenerative lumbar scoliosis caused by asymmetric stress.

METHODS

Thirty-six New Zealand white rabbits were randomly divided into 3 groups (n=12): Group A with aspiration of the nucleus pulposus to induce disc degeneration; Group B with removal of the left capsule from the facet joints at L3/4 to L5/6 to induce degeneration; and Group C with both treatments. Springs were deployed on the left adjacent facets at L3/4, L5/6 and L5/6 to stress the facet joints. Serial radiographs were taken at 3 and 6 months, and the facet joint tissues were sampled at 6 months for Safranin O-fast green staining to assess the severity of cartilage degeneration based on the Mankin score.

RESULTS

The Cobb angle differed significantly among the 3 groups (F=24.865, P=0.000). In all the groups, the Cobb angles at 6 months increased significantly as compared with that at 3 months (P <0.05). The Cobb angles were significantly greater in group C than in the other 2 groups at both 3 and 6 months (P <0.05) but showed no significant difference between Groups A and B (P>0.05). The severity of facet joint degeneration also differed significantly among the 3 groups (F= 22.009, P=0.000), and was the most severe in group C (P <0.05); facet joint degeneration was more severe in group B than in group A (P <0.05).

CONCLUSIONS

Facet joint degeneration is an important factor that contributes to the development of degenerative lumbar scoliosis. Disc degeneration and facet joints degeneration can lead to lumbar scoliosis, which in turn aggravates disc degeneration, facet joints degeneration and asymmetric stress, thus forming a vicious circle to further exacerbate lumbar scoliosis.

Toward a cure for lumbar spinal stenosis: The potential of interspinous process decompression

There is a growing impetus to treat aging as a disease in the quest to significantly extend the human life span through cellular regeneration methods. This approach, while promising, overlooks the fact that the evolutionary adaptation to bipedalism puts the human body in a distinctively vulnerable biomechanical and functional position. Orthograde human posture places unusually-high axial compressive loads on the weight-bearing joints of the skeleton, resulting in arthritic deterioration with aging. The effects are particularly robust in the lumbar spine were age-related degeneration, most commonly lumbar spinal stenosis (LSS), is ubiquitous among the elderly. It is postulated that re-establishing a favorable mechanical environment via interventions that unload the affected spinal joint complex may mitigate and potentially reverse the structural damage that is the cardinal pathoanatomical feature of this disease. The hypothesis of this paper is that a minimally-invasive surgical procedure, interspinous process decompression (IPD), which utilizes a stand-alone intervertebral spacer, effectively unloads the diseased spinal motion segment providing a healthy micro-environment to reverse and repair age-related and genetic deterioration of the spinal motion segment. Several lines of supporting evidence are provided from long-term follow-up results of a randomized controlled trial of IPD safety and effectiveness of the Superion® device including clinical outcomes, reoperation rates, opioid analgesic usage and advanced imaging utilization. All of these outcomes show uniquely-favorable trends with time that imply that the benefits of IPD are structural. The compendium of evidence suggests that IPD offers both a durable palliative effect due to direct blocking of back extension and a disease-modifying effect due to unloading of the spinal joint complex.

Incidence and risk factors of facet joint violation following percutaneous kyphoplasty for osteoporotic vertebral compression fractures

BACKGROUND

Percutaneous kyphoplasty (PKP) has been widely used to osteoporotic vertebral compression fractures (OVCFs). No previous investigations have reported the incidence and risk factors of facet joint violation (FJV) caused by PKP.

PURPOSE

To determine the incidence and risk factors of FJV following PKP in patients with OVCFs.

MATERIAL AND METHODS

We reviewed a total of 153 patients who underwent bilateral PKP. Postoperative computed tomography (CT) scans were assessed to determine the degree of FJV owing to invasion by a puncture trocar. Clinical outcomes, including visual analogue scale (VAS) scores and Oswestry Disability Index (ODI) scores, were collected from all patients. Clinical and radiological data were analyzed to identify the risk factors for FJV.

RESULTS

FJV caused by PKP affected 18.9% of patients and 9.6% of facet joints; approximately 3.9% and 5.7% of facet joints were considered to have grade 1 and grade 2 violations, respectively. There were significant differences between the FJV and non-FJV groups in VAS and ODI scores after surgery. Significant differences were found with respect to the facet joint angle (FJA), the pedicle diameter (PD), and the distance from the entry point to the facet joint space (DEF). Multiple logistic regression analysis indicated that an FJA > 55°, a PD < 5 mm, and a DEF < 5 mm were independent risk factors for FJV.

CONCLUSION

The placement of a puncture trocar can cause FJV in patients with OVCFs and impact clinical outcomes after PKP. Special attention should be given to patients with an FJA > 55°, a PD < 5 mm, and a DEF < 5 mm.

Stable Spondylolisthesis: Should Management Change Based on Presence of Facet Cysts?

STUDY DESIGN

This is a retrospective cohort review.

OBJECTIVE

To determine whether a correlation exists between facet cysts and lumbar instability.

SUMMARY OF BACKGROUND DATA

Lumbar facet cysts are common degenerative entities observed in patients with low-grade spondylolisthesis at a rate of 10%-50%. Surgical management with partial facetectomy with or without fusion remains controversial.

METHODS

Review of 86 patients with lumbar degenerative spondylolisthesis is performed. Preoperative magnetic resonance imagings were reviewed for the presence of lumbar facet cysts and Facet Fluid Indices (FFI)-calculated as the ratio of facet fluid width to facet width. Instability was defined as a difference of >3 mm in vertebral displacement between flexion and extension radiographs. T tests and the Pearson correlation analyses were used to determine statistical significance.

RESULTS

In total, 26 patients had unstable and 60 had stable spondylolisthesis. Facet cysts were present at an overall prevalence of 30.1%-in 10/26 patients in the unstable group and in 18/60 patients in the stable group (P>0.05). The average FFIs for the unstable and stable groups were 0.13 and 0.09, respectively (P>0.05). FFI in patients with facet cysts was significantly higher than those without (P<0.05). In addition, the group with facet cysts had a significantly higher proportion of patients with FF effusions >3 mm.

CONCLUSIONS

Lack of correlation with instability hints that the presence of facet cysts may not indicate instability in lumbar degenerative spondylolisthesis. Therefore, presence of facet cysts in static magnetic resonance imaging revealing spondylolisthesis should not preclude the physician from performing dynamic films to evaluate for instability. Significantly higher FFI in patients with facet cysts reaffirms the degenerative pathophysiology involved in their formation. Although this is not an outcomes study, it does spark interest into whether patients with stable spondylolisthesis and concurrent facet cysts are suitable for partial facetectomy alone with fusion.

Biomechanical comparison of percutaneous posterior endoscopic cervical discectomy and anterior cervical decompression and fusion on the treatment of cervical spondylotic radiculopathy

Background

Cervical spondylotic radiculopathy is a common spinal disease. The traditional surgical treatment consists of anterior cervical decompression and fusion (ACDF), but it presents problems such as trauma and fusion complications. Percutaneous posterior endoscopic cervical discectomy (PPECD) is a new minimally invasive technology that has produced good clinical outcome, but further biomechanical comparisons are needed to guide the clinical work. The goal of this study was to compare the biomechanical characteristics of the two methods by finite element analysis.

Method

On the basis of the computed tomography scanning data of five cases of cervical spondylosis after PPECD surgery, five cases after ACDF surgery, and five non-surgical patients, software (Mimics 15.0, HyperMesh 12.0, and Abaqus 6.13) was adopted to establish a C1–C7 segment 3D finite element model. We also applied 50 N vertical load on the C1 surface and 1.5 Nm torque, simulated the anteflexion, rear protraction, and left and right lateral flexion and rotation, and observed the stability, stress distribution, and Cobb angular change of the surgical section of the cervical vertebra under different working conditions.

Result

The postoperative model under different working conditions demonstrated poorer stability than the non-surgical group, but the stability of the PPECD group was close to that of the non-surgical group. The stability of the ACDF group was the worst, especially when making lateral bending and posterior extension. The ACDF group also showed significant differences. The PPECD group showed uniform stress distribution, whereas the ACDF group was under large stress, which was primarily concentrated in the internal fixation system. In addition, the implant showed the potential for fracture. The Cobb angle of surgery section of the PPECD group was smaller than that of the ACDF group, and the stability of the section was good.

Conclusion

From the perspective of finite element analysis, the cervical vertebrae after PPECD treatment showed good biomechanical performance and stability.