Prevalence and Factors of Osteoporosis and High Risk of Osteoporotic Fracture in Patients with Ankylosing Spondylitis: A Multicenter Comparative Study of Bone Mineral Density and the Fracture Risk Assessment Tool

Iatrogenic vertebral fracture in ankylosed spine during liver transplantation: a case report and biomechanical study using finite element method

PURPOSE

The occurrence of an iatrogenic vertebral fracture during non-spinal digestive surgery is an exceptional event that has not been previously documented. Our study aims to explain the occurrence of this fracture from a biomechanical perspective, given its rarity. Using a finite element model of the spine, we will evaluate the strength required to induce a vertebral fracture through a hyperextension mechanism, considering the structure of the patient's spine, whether it is ossified or healthy.

METHODS

A 70-year-old patient was diagnosed T12 fracture during a liver transplantation on ankylosed spine. We use a finite element model of the spine. Different mechanical properties were applied to the spine model: first to a healthy spine, the second to a osteoporotic ossified spine. The displacement and force imposed at the Sacrum, the time and location of fractures initiation were recorded and compared between the two spine conditions.

RESULTS

A surgical treatment is done associating decompression with posterior fixation. After biomechanical study, we found that the fracture initiation occurred for the ossified spine after a sacrum displacement of 29 mm corresponding to an applied force of 65 N. For the healthy spine it occurred at a sacrum displacement of 52 mm corresponding to an applied force of 350 N.

CONCLUSION

The force required to produce a type B fracture in an ankylosed spine is 5 times less than in a healthy spine. These data enable us to propose several points of management to avoid unexpected complications with ankylosed spines during surgical procedures.

LEVEL OF EVIDENCE

IV.

The state of bone mineral density in men with ankylosing spondylitis and its relationship with the course of the disease

Introduction

The aim of the study was to study the structural and functional state of bone tissue in men with ankylosing spondylitis (AS) and to assess its relationship with the course of the disease.

Material and methods

A study was conducted with the participation of 105 men with AS aged from 22 to 59 years (average age was 40.7 ±0.8 years) with a duration of the disease of 8.7 ±0.5 years and 29 persons of the control group. Disease activity and the degree of functional limitations were determined by the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI), Ankylosing Spondylitis Activity Score correlated with C-reactive protein (ASDAS-CRP) and the Bath Ankylosing Spondylitis Functional Index (BASFI). Laboratory examination included determination of C-reactive protein (CRP). Bone mineral density (BMD) of the lumbar spine and femoral neck was determined by the method of dual-energy X-ray absorptiometry on the Hologic Discovery Wi device (S/N 87227).

Results

In men with AS, a decrease in BMD (according to the Z-score and T-score) was found in 41.9%, while the percentage of patients with osteoporosis at the level of the femoral neck and lower back was 16.7%. Development of osteoproliferative changes was observed in 42 (40%) patients. Bone mass loss was associated with high activity of the inflammatory process according to ASDAS, BASDAI (r = -0.39, -0.65), and CRP (r = -0.28, -0.38) and low functional capacity according to BASFI (r = -0.27, -0.59), while syndesmophytosis had a reliable association with the age of the patients, the duration of the disease and low functional capacity. Low-energy fractures occurred in 11.4% of men with AS. The presence of fractures was associated with high disease activity (ASDAS, BASDAI, CRP) and was not related to the age of the patients or duration of the disease.

Conclusions

A decrease in BMD and the development of fractures were closely associated with high activity of the inflammatory process and low functional capacity, while syndesmophytosis was related to the age of patients and the duration of the disease.

The prevalence of vertebral fractures in diffuse idiopathic skeletal hyperostosis and ankylosing spondylitis: A systematic review and meta-analysis

Background

Subjects with ankylosing spinal disorders, including diffuse idiopathic skeletal hyperostosis (DISH) and ankylosing spondylitis (AS) are more prone to vertebral fractures and frequently present with neurological deficit compared to the patients without an ankylosed spine. Moreover, prevalent vertebral fractures are an important predictor for subsequent fracture risk. However, the pooled fracture prevalence for DISH is unknown and less recent for AS. We aimed to systematically investigate the prevalence and risk of vertebral fractures in DISH and AS populations.

Methods

Publications in Medline and EMBASE were searched from January 1980 until July 2023 for cohort studies reporting vertebral fractures in AS and DISH. Data on prevalence were pooled with random effects modeling after double arcsine transformation. Heterogeneity was assessed with I2 statistics and we performed subgroup analysis and meta-regression to explore sources of heterogeneity.

Results

We included 7 studies on DISH (n = 1,193, total fractures = 231) with a pooled vertebral fracture prevalence of 22.6% (95%CI: 13.4%-33.4%). For AS, 26 studies were included (n = 2,875, total fractures = 460) with a pooled vertebral fracture prevalence of 15.2% (95%CI: 11.6%-19.1%). In general, fracture prevalence for AS remained similar for several study-level and clinically relevant characteristics, including study design, diagnostic criteria, spine level, and patient characteristics in subgroup analysis. AS publications from 2010 to 2020 showed higher fracture prevalence compared to 1990 to 2010 (18.6% vs. 11.6%). Fractures in DISH were most common at the thoracolumbar junction, whereas for AS, the most common location was the mid-thoracic spine.

Conclusions

Vertebral fractures are prevalent in AS and DISH populations. Differences in fracture distribution along the spinal axis exist between the 2 disorders. Additional longitudinal studies are needed for incident fracture assessment in patients with ankylosing spinal disorders.

Pathogenesis, assessment, and management of bone loss in axial spondyloarthritis

INTRODUCTION

Axial spondyloarthritis (axSpA) presents a complex scenario where both new bone formation in entheseal tissues and significant trabecular bone loss coexist, emphasizing the intricate nature of bone dynamics in this context.

METHODS

A search of the literature was conducted to compose a narrative review exploring the pathogenesis, possible assessment methods, and potential management options for axSpA.

RESULTS

While chronic systemic and local inflammation contribute to bone loss, the mechanisms behind axSpA-associated bone loss exhibit distinct characteristics influenced by factors like mechanical stress and the gut microbiome. These factors directly or indirectly stimulate osteoclast differentiation and activation through the RANK-RANKL axis, while simultaneously impeding osteoblast differentiation via negative regulation of bone anabolic pathways, including the Wnt signaling pathway. This disruption in the balance between bone-resorbing osteoclasts and bone-forming osteoblasts contributes to overall bone loss in axSpA. Early evaluation at diagnosis is prudent for detecting bone changes. While traditional dual x-ray absorptiometry (DXA) has limitations due to potential overestimation from spinal new bone formation, alternative methods like trabecular bone score (TBS), quantitative CT (QCT), and quantitative ultrasound (QUS) show promise. However, their integration into routine clinical practice remains limited. In addition to approved anti-inflammatory drugs, lifestyle adjustments like regular exercise play a key role in preserving bone health. Tailoring interventions based on individual risk profiles holds potential for mitigating bone loss progression.

CONCLUSION

Recognizing the pivotal role of bone loss in axSpA underscores the importance of integrating regular assessments and effective management strategies into clinical practice. Given the multifaceted contributors to bone loss in axSpA, a multidisciplinary approach is essential.

Interaction effects of significant risk factors on low bone mineral density in ankylosing spondylitis

Background

To analyze individually and interactively critical risk factors, which are closely related to low bone mineral density (BMD) in patient with ankylosing spondylitis (AS).

Methods

A total of 249 AS patients who visited China-Japan Friendship Hospital were included in this training set. Patients with questionnaire data, blood samples, X-rays, and BMD were collected. Logistic regression analysis was employed to identify key risk factors for low BMD in different sites, and predictive accuracy was improved by incorporating the selected significant risk factors into the baseline model, which was then validated using a validation set. The interaction between risk factors was analyzed, and predictive nomograms for low BMD in different sites were established.

Results

There were 113 patients with normal BMD, and 136 patients with low BMD. AS patients with hip involvement are more likely to have low BMD in the total hip, whereas those without hip involvement are more prone to low BMD in the lumbar spine. Chest expansion, mSASSS, radiographic average grade of the sacroiliac joint, and hip involvement were significantly associated with low BMD of the femoral neck and total hip. Syndesmophytes, hip involvement and higher radiographic average grade of the sacroiliac joint increases the risk of low BMD of the femoral neck and total hip in an additive manner. Finally, a prediction model was constructed to predict the risk of low BMD in total hip and femoral neck.

Conclusions

This study identified hip involvement was strongly associated with low BMD of the total hip in AS patients. Furthermore, the risk of low BMD of the femoral neck and total hip was found to increase in an additive manner with the presence of syndesmophytes, hip involvement, and severe sacroiliitis. This finding may help rheumatologists to identify AS patients who are at a high risk of developing low BMD and prompt early intervention to prevent fractures.

Osteoimmunology of Spondyloarthritis

The mechanisms underlying the development of bone damage in the context of spondyloarthritis (SpA) are not completely understood. To date, a considerable amount of evidence indicates that several developmental pathways are crucially involved in osteoimmunology. The present review explores the biological mechanisms underlying the relationship between inflammatory dysregulation, structural progression, and osteoporosis in this diverse family of conditions. We summarize the current knowledge of bone biology and balance and the foundations of bone regulation, including bone morphogenetic protein, the Wnt pathway, and Hedgehog signaling, as well as the role of cytokines in the development of bone damage in SpA. Other areas surveyed include the pathobiology of bone damage and systemic bone loss (osteoporosis) in SpA and the effects of pharmacological treatment on focal bone damage. Lastly, we present data relative to a survey of bone metabolic assessment in SpA from Italian bone specialist rheumatology centers. The results confirm that most of the attention to bone health is given to postmenopausal subjects and that the aspect of metabolic bone health may still be underrepresented. In our opinion, it may be the time for a call to action to increase the interest in and focus on the diagnosis and management of SpA.