Criteria for Early-Phase Diffuse Idiopathic Skeletal Hyperostosis: Development and Validation

Bone and entheseal targets for growth factors in diffuse idiopathic skeletal hyperostosis

INTRODUCTION

Diffuse idiopathic skeletal hyperostosis (DISH) is a common condition of the adult skeleton where new bone growth occurs in entheseal and bony regions. The cause for the new bone growth is unclear but many lines of evidence point to a role for growth factors linked to abnormal metabolism in these patients. The bone targets for these presumed growth factors are poorly defined. This review summarises the clinical evidence relevant to the sites of origin of new bone formation in DISH to better define potential cellular targets for bone growth in DISH.

METHODS

This is a narrative review of relevant papers identified from searches of PubMed and online journals.

RESULTS

Sites of new bone growth in the enthesis were identified in patients with DISH, with likely cellular targets for growth factors being mesenchymal stem cells in the outer part of the enthesis. Similar undifferentiated skeletal stem cells are present in the outer annulus fibrosis and in the bony eminences of vertebral bodies and other bones, with the potential for response to growth factors.

CONCLUSION

Mesenchymal stem cells are present in specific entheseal and bony locations that are likely responsive to putative growth factors leading to new bone formation characteristic of DISH. Further study of these regions in the context of metabolic abnormalities in DISH will allow for better understanding of the pathophysiology of this common condition.

Diffuse idiopathic skeletal hyperostosis: Imaging findings with special focus on extraspinal involvement

Diffuse Idiopathic Skeletal Hyperostosis (IDHS) is a multifactorial disease with a high prevalence and that is frequently detected incidentally in imaging tests. Most of its diagnostic criteria are focused on axial involvement and more specifically the spine. However, peripheral involvement in DISH is less well known despite its non insignificant frequency. DISH can be associated with serious complications, the most severe being vertebral fractures in low energy trauma and dysphagia or airway obstruction in cervical involvement. Knowing how to identify the patterns of peripheral involvement of DISH and its complications helps in the radiological and clinical management of patients with this disease.

Significant overlap of inflammatory and degenerative features on imaging among patients with degenerative disc disease, diffuse idiopathic skeletal hyperostosis and axial spondyloarthritis: a real-life cohort study

BACKGROUND

Differentiating between degenerative disc disease (DDD), diffuse idiopathic skeletal hyperostosis (DISH), and axial spondyloarthritis (axSpA) represents a diagnostic challenge in patients with low back pain (LBP). We aimed to evaluate the distribution of inflammatory and degenerative imaging features in a real-life cohort of LBP patients referred to a tertiary university rheumatology center.

METHODS

In a retrospective cross-sectional analysis of patients referred for LBP, demographics, symptom information, and available imaging were collected. SpA-like changes were considered in the spine in the presence of one of the following lesions typically related to SpA: erosions, sclerosis, squaring, and syndesmophytes on conventional radiographs (CR) and bone marrow oedema (BMO), erosions, sclerosis, and fat lesions (FL) on MRI. SIJ CR were graded per New York criteria; on MRIs, SIJs were evaluated by quadrant for BMO, erosions, FL, sclerosis and ankylosis, similar to the approach used by the Berlin SIJ MRI scoring system. The final diagnosis made by the rheumatologist was the gold standard. Data were presented descriptively, by patient and by quadrant, and compared among the three diagnosis groups.

RESULTS

Among 136 referred patients, 71 had DDD, 38 DISH, and 27 axSpA; median age 62 years [IQR55-73], 63% males. On CR, SpA-like changes were significantly higher in axSpA in the lumbar (50%, vs. DDD 23%, DISH 22%), in DISH in the thoracic (28%, vs. DDD 8%, axSpA 12%), and in DDD in the cervical spine (67% vs. DISH 0%, axSpA 33%). On MRI, BMO was significantly higher in DISH in the thoracic (37%, vs. DDD 22%, axSpA 5%) and equally distributed in the lumbar spine (35-42%). FL were significantly more frequently identified in DISH and axSpA in the thoracic (56% and 52%) and DDD and axSpA in the lumbar spine (65% and 74%, respectively). Degenerative changes were frequent in the three groups. Sacroiliitis (NY criteria) was identified in 49% (axSpA 76%, DDD 48%, DISH 29%).

CONCLUSION

A significant overlap was found among DDD, DISH, and axSpA for inflammatory and degenerative imaging features. Particularly, SpA-like spine CR features were found in one-fourth of patients with DISH, and MRI BMO was found in one-third of those patients.

Association between serum interleukin-17 levels and ectopic bone formation in OPLL patients with DISH

OBJECTIVE

To investigate the relationship between the severity and morphology of heterotopic ossification in the spinal ligaments including sacroiliac (SI) joints, and serum interleukin-17 (IL-17) levels in patients with ossification of the posterior longitudinal ligament (OPLL) with or without diffuse idiopathic skeletal hyperostosis (DISH), as well as a non-OPLL group.

METHODS

A total of 103 patients with OPLL [DISH (-), n = 50; DISH (+), n = 53] and 53 age- and gender-matched controls were included. The serum levels of IL-17 were analysed, and the severity of ectopic ossification and the morphology of ectopic bone formation were evaluated. The SI joint morphological variations were categorized into four types.

RESULTS

No significant differences were found in serum IL-17 levels between the OPLL and control groups. However, the DISH (+) group showed higher IL-17 levels than the DISH (-) group, especially in female patients (P = 0.003). Additionally, IL-17 levels were positively correlated with the number of flat vertebral units, this being one of the characteristic DISH ossification types (R2 = 0.199, P = 0.012). IL-17 levels in the type showing bridging osteophyte and bone fusion were significantly higher in the DISH (+) group than in the DISH (-) group.

CONCLUSION

The morphological characteristics of paravertebral bone formation in the entire spine, including the SI joint, are likely associated with serum IL-17 levels in OPLL. These findings provide pathological and serological evidence of local inflammation contributing to paravertebral ossification of OPLL patients.

Spatiotemporal changes in imaging features associated with diffuse idiopathic skeletal hyperostosis (DISH)

OBJECTIVES

The purpose of our study was to characterise spatiotemporal features of disease progression in people with diffuse idiopathic skeletal hyperostosis (DISH), early-phase DISH, and those not meeting either criterion who had repeated CT scans of the thoracic spine.

METHODS

A retrospective study was designed in collaboration with the Rochester Epidemiology Project to evaluate completeness of ectopic bridging across the thoracic spine and corresponding disease status over an average of 2.7 years (range from 0.2 to 15.0 years) in a cohort of 83 female and 74 male individuals.

RESULTS

Over 15% of individuals displayed changes in imaging features over time that resulted in a revised diagnosis along the continuum of DISH. Early-phase DISH was marked by new involvement of previously unaffected motion segments, estimated to occur over 2.1 years. Advanced presentations of DISH were marked by increased prevalence of complete bridging (average two of three available motion segments), estimated to occur over 2.6-2.9 years. Localised nodules of ectopic mineralisation external to and within the intervertebral disc were regularly observed in early-phase DISH.

CONCLUSIONS

This is the first characterisation of spatiotemporal features across all phases of DISH, indicating that progression of DISH is characterised by distinct features at different phases along the disease continuum. Localised nodules of mineralisation in the spinal ligaments and within the intervertebral discs coincident with early phases of the disease may be a key factor in the pathogenesis of DISH.

Prevalence of diffuse idiopathic skeletal hyperostosis (DISH) and early-phase DISH across the lifespan of an American population

OBJECTIVES

DISH is a common musculoskeletal disorder; however, the imaging features and disease continuum from early to advanced stages is poorly understood. The purpose of this study was to evaluate the prevalence of DISH and early-phase DISH in an American population and to assess the extent and pattern of ectopic mineralization across the thoracic spine.

METHODS

Data were retrieved in collaboration with the Rochester Epidemiology Project. We conducted a retrospective image evaluation of a sample of individuals over 19 years of age with CT of the thoracic spine from a Northern US catchment area. Stratified random sampling by age and sex was used to populate the study. We examined the prevalence and extent of ectopic mineralization along the thoracic spine using previously established criteria.

RESULTS

A total of 1536 unique images (766 female and 770 male individuals) including 16 710 motion segments were evaluated for imaging features of the continuum of DISH. Collectively, 40.5% of all motion segments evaluated displayed evidence of ectopic mineralization in the thoracic spine. The prevalence of early-phase DISH was 13.2% (10.4% of female and 15.8% of male individuals). The prevalence of established DISH was 14.2% (7.4% of female and 20.9% of male individuals). Remarkable heterogeneity was detected in individuals within each disease classification, based on the extent of the thoracic spine affected and degree of mineralization.

CONCLUSIONS

The continuum of imaging features associated with DISH is detected in more than one in four adults and both sexes in an American population.

Post-traumatic spinal hematoma in diffuse idiopathic skeletal hyperostosis (DISH)

OBJECTIVES

To determine the incidence of spinal hematoma and its relation to neurological deficit after trauma in patients with spinal ankylosis from diffuse idiopathic skeletal hyperostosis (DISH).

MATERIALS AND METHODS

A retrospective review of 2256 urgent or emergency MRI referrals over a period of 8 years and nine months revealed 70 DISH patients who underwent CT and MRI scans of the spine. Spinal hematoma was the primary outcome. Additional variables were spinal cord impingement, spinal cord injury (SCI), trauma mechanism, fracture type, spinal canal narrowing, treatment type, and Frankel grades during injury, before and after treatment. Two trauma radiologists reviewed MRI scans blinded to initial reports.

RESULTS

Of 70 post-traumatic patients (54 men, median age 73, IQR 66-81) with ankylosis of the spine from DISH, 34 (49%) had spinal epidural hematoma (SEH) and 3 (4%) had spinal subdural hematoma, 47 (67%) had spinal cord impingement, and 43 (61%) had SCI. Ground-level fall (69%) was the most common trauma mechanism. A transverse, AO classification type B spine fracture (39%) through the vertebral body was the most common injury type. Spinal canal narrowing (p < .001) correlated and spinal cord impingement (p = .004) associated with Frankel grade before treatment. Of 34 patients with SEH, one, treated conservatively, developed SCI.

CONCLUSIONS

SEH is a common complication after low-energy trauma in patients with spinal ankylosis from DISH. SEH causing spinal cord impingement may progress to SCI if not treated by decompression.

CLINICAL RELEVANCE STATEMENT

Low-energy trauma may cause unstable spinal fractures in patients with spinal ankylosis caused by DISH. The diagnosis of spinal cord impingement or injury requires MRI, especially for the exclusion of spinal hematoma requiring surgical evacuation.

KEY POINTS

• Spinal epidural hematoma is a common complication in post-traumatic patients with spinal ankylosis from DISH. • Most fractures and associated spinal hematomas in patients with spinal ankylosis from DISH result from low-energy trauma. • Spinal hematoma can cause spinal cord impingement, which may lead to SCI if not treated by decompression.

Imaging Features of Early Diffuse Idiopathic Skeletal Hyperostosis (pre-DISH): Analysis of Progression of Ligament Ossification over 5 Years by Computed Tomography

Introduction

Some patients who have not been diagnosed with diffuse idiopathic skeletal hyperostosis (DISH) (patients in the preclinical stage of DISH [pre-DISH]) may develop DISH in the future. However, there are currently no clearly defined diagnostic criteria for pre-DISH. This study aims to define pre-DISH by analyzing the change in the ossification extent in each intervertebral space in the thoracic and lumbar spines over time using computed tomography (CT).

Methods

Of the patients who underwent CT of the thoracic to pelvic region at least twice from 2009 to 2018, 188 who underwent CT at an interval of 5 years to 5 years and 2 months were enrolled. The prevalence of DISH during the first and second CT scans was investigated. The pre-DISH feature was defined, and the prevalence of pre-DISH on the first CT and the change after 5 years in patients with pre-DISH was investigated.

Results

Of the 188 patients, 37 (19.7%) and 48 (25.5%) were diagnosed with DISH on the first and second CT scans, respectively. Pre-DISH was defined as the ossification characterized by the modified Mata score of three contiguous intervertebral spaces with a score of ≥2 points (222; 2 points, ligament ossification of half or more of the intervertebral disc height but incomplete fusion), and 52 patients were diagnosed with pre-DISH. Of the 52 patients with a score of ≥(222), 11 (21.2%) were diagnosed with DISH 5 years later.

Conclusions

Patients who have three contiguous intervertebral spaces with a modified Mata score of 2 or 3 points should be considered pre-DISH.

Genetics implicates overactive osteogenesis in the development of diffuse idiopathic skeletal hyperostosis

Diffuse idiopathic skeletal hyperostosis (DISH) is a condition where adjacent vertebrae become fused through formation of osteophytes. The genetic and epidemiological etiology of this condition is not well understood. Here, we implemented a machine learning algorithm to assess the prevalence and severity of the pathology in ~40,000 lateral DXA scans in the UK Biobank Imaging cohort. We find that DISH is highly prevalent, above the age of 45, ~20% of men and ~8% of women having multiple osteophytes. Surprisingly, we find strong phenotypic and genetic association of DISH with increased bone mineral density and content throughout the entire skeletal system. Genetic association analysis identified ten loci associated with DISH, including multiple genes involved in bone remodeling (RUNX2, IL11, GDF5, CCDC91, NOG, and ROR2). Overall, this study describes genetics of DISH and implicates the role of overactive osteogenesis as a key driver of the pathology.

Diffuse Idiopathic Skeletal Hyperostosis (DISH): New evidence from micro-XCT scanning

OBJECTIVE

To observe and describe the development and underlying structure of the spinal manifestations of individuals osteologically diagnosed with DISH (Diffuse Idiopathic Skeletal Hyperostosis), using micro-XCT imaging.

MATERIALS

A total of 72 individuals with DISH were identified in two modern skeletal collections in South Africa.

METHODS

Vertebral columns affected by DISH were scanned at the micro-focus x-ray computed tomography facility at the Nuclear Energy Corporation of South Africa. Four features were macroscopically examined: (1) the origin of the new bone growth; (2) retention of the original vertebral cortex at the site of the new bone formation associated with DISH; (3) evidence of trabecular bone with or without sclerosis on the anterolateral surface of affected vertebrae; and (4) abnormal areas of osteosclerosis beyond features associated with DISH.

RESULTS

Considerable variation across and between the four recorded features was found. Of note, 81% (n = 58) of individuals had both developed trabecular bone within the flowing new bone formation (feature 3), without retention of the original vertebral cortex (feature 2).

CONCLUSIONS

Possible localised erosive/inflammatory processes destroyed the original cortex of the vertebral body and resulted in the expansion of trabeculae with new bone formation.

SIGNIFICANCE

Micro-XCT imaging shed new light on the development of DISH, adding to literature suggesting that it could be an inflammatory disease.

LIMITATIONS

Clinical histories of the individuals were not known.

SUGGESTIONS FOR FURTHER RESEARCH

The role of chronic inflammatory disease in the development of DISH should be further explored including both the extra-spinal and spinal manifestations.

A Scoring System for Anterior Longitudinal Ligament Ossification of the Lumbar Spine in Diffuse Idiopathic Skeletal Hyperostosis: Relationship Between the Extent of Ligament Ossification and the Range of Motion

STUDY DESIGN

Retrospective observational study.

OBJECTIVE

To investigate the relationship between the extent of ligament ossification and the range of motion (ROM) of the lumbar spine and develop a new scoring system.

METHODS

Forty-three patients (30 men and 13 women) with lumbar spinal canal stenosis who underwent decompression from January to December 2018. Ligament ossification at L1/2 to L5/S was assessed on plain X-ray (Xp) and computed tomography (CT) using a modified Mata scoring system (0 point: no ossification, 1 point: ossification of less than half of the intervertebral disc height, 2 points: ossification of half or more of the intervertebral disc height, 3 points: complete bridging), and the intra-rater and inter-rater reliability of the scoring was assessed. The relationship of the scores with postoperative lumbar ROM was investigated.

RESULT

Intra-rater reliability was high (Cronbach's α was 0.74 for L5/S on Xp but 0.8 or above for other sections), as was inter-rater reliability (Cronbach's α was 0.8 or above for all the segments). ROM significantly decreased as the score increased (scores 1 to 2, and 2 to 3). A significant moderate negative correlation was found between the sum of the scores at L1/2-L5/S and the ROM at L1-S (ρ = - 0.4493, P = 0.025).

CONCLUSION

Our scoring system reflects lumbar mobility and is reproducible. It is effective for assessing DISH in fractures and spinal conditions, and monitoring effects on treatment outcomes and changes over time.

Diffuse Idiopathic Skeletal Hyperostosis and Ankylosing Spondylitis: A Challenging Case and Review of the Literature

Background

Diffuse idiopathic skeletal hyperostosis and spondyloarthritis share similarities in clinical and radiological findings. In this article, we report a case of overlapping of these two hyperostotic diseases followed by an extensive narrative review of the literature focusing on the gray areas in the diagnosis of diffuse idiopathic skeletal hyperostosis.

Case description

We report the case of simultaneous diffuse idiopathic skeletal hyperostosis and ankylosing spondylitis in a 57-year-old man. The diagnosis was made after many collegial meetings based on solid radiological arguments.

Conclusion

Review of the literature reveals many uncertainties in the diagnosis of diffuse idiopathic skeletal hyperostosis, especially in the radiological evaluation of sacroiliac joints. Diffuse idiopathic skeletal hyperostosis and ankylosing spondylitis frequently overlap in important radiological features leading to diagnostic ambiguity and they can also co-exist in the same patient.

The natural course of bridging osteophyte formation on MRI—A pictorial illustration

Diffuse skeletal hyperostosis is a common spinal disorder, but its pathophysiology is mostly unclear. The disorder can lead to a variety of symptoms, but many patients remain relatively asymptomatic. We present a case demonstrating the development of bridging osteophytes on a series of magnetic resonance images. An elderly person's spine was scanned repeatedly due to non-specific back pain during the last 4 years and the consecutive images revealed the formation of a bony bridge in the lumbar spine. Extensive bone marrow edema was seen during the formation of the osteophyte, suggestive of an ongoing inflammatory process. This case underlines that the inflammatory reaction in diffuse skeletal hyperostosis can be intense and prolonged, and its role might be worth studying further.

The prevalence of diffuse idiopathic skeletal hyperostosis in England and Catalonia from the Roman to the post-medieval periods

OBJECTIVE

Evaluate the prevalence of DISH through time from the Roman to the post-Medieval period in England and Catalonia.

MATERIAL

281 individuals from England and 247 from Catalonia were analyzed.

METHODS

Adult individuals with at least three well-preserved lower thoracic vertebral bodies were analyzed. DISH was assessed considering the early stages of development. Diachronic and geographical dietary shifts were investigated using reported light isotope data, archaeological reports and historical documentation.

RESULTS

Males and older individuals showed consistently higher prevalence of DISH, however, only the English sample showed a significant difference between males and females in the prevalence of DISH. No significant difference was found in the prevalence of DISH though time (from Roman to post medieval periods) nor across regions (England and Catalonia).

CONCLUSION

The development of DISH is probably influenced by a combination of factors including increasing age and sex.

SIGNIFICANCE

This is the first exhaustive analysis of DISH in ancient Catalan populations and the first that considers the early stages of DISH.

LIMITATIONS

Reduced sample size, particularly in post-medieval samples, as a result of the available excavated samples and the inclusion criteria adopted.

FUTURE RESEARCH

Include rural, religious and high-status samples in the analysis of DISH. Re-assess the prevalence of DISH in post-medieval populations.

Galectin-3 Enhances Osteogenic Differentiation of Precursor Cells From Patients With Diffuse Idiopathic Skeletal Hyperostosis via Wnt/β-Catenin Signaling

Diffuse idiopathic skeletal hyperostosis (DISH) is a noninflammatory skeletal disease characterized by the progressive ectopic ossification and calcification of ligaments and enthuses. However, specific pathogenesis remains unknown. Bone marrow mesenchymal stem cells (BMSCs) are a major source of osteoblasts and play vital roles in bone metabolism and ectopic osteogenesis. However, it is unclear whether BMSCs are involved in ectopic calcification and ossification in DISH. The current study aimed to explore the osteogenic differentiation abilities of BMSCs from DISH patients (DISH-BMSCs). Our results showed that DISH-BMSCs exhibited stronger osteogenic differentiation abilities than normal control (NC)-BMSCs. Human cytokine array kit analysis showed significantly increased secretion of Galectin-3 in DISH-BMSCs. Furthermore, Galectin-3 downregulation inhibited the increased osteogenic differentiation ability of DISH-BMSCs, whereas exogenous Galectin-3 significantly enhanced the osteogenic differentiation ability of NC-BMSCs. Notably, the increased Galectin-3 in DISH-BMSCs enhanced the expression of β-catenin as well as TCF-4, whereas attenuation of Wnt/β-catenin signaling partially alleviated Galectin-3-induced osteogenic differentiation and activity in DISH-BMSCs. In addition, our results noted that Galectin-3 interacted with β-catenin and enhanced its nuclear accumulation. Further in vivo studies showed that exogenous Galectin-3 enhanced ectopic bone formation in the Achilles tendon in trauma-induced rats by activating Wnt/β-catenin signaling. The current study indicated that enhanced osteogenic differentiation of DISH-BMSCs was mainly attributed to the increased secretion of Galectin-3 by DISH-BMSCs, which enhanced β-catenin expression and its nuclear accumulation. Our study helps illuminate the mechanisms of pathological osteogenesis and sheds light on the possible development of potential therapeutic strategies for DISH treatment. © 2022 American Society for Bone and Mineral Research (ASBMR).

Diffuse Idiopathic Skeletal Hyperostosis of the Spine: Pathophysiology, Diagnosis, and Management

Diffuse idiopathic skeletal hyperostosis (DISH) is an ankylosing condition affecting up to 32.5% of the general cohort. Although often asymptomatic, affected individuals may present with back pain, stiffness, dysphagia, functional decline, and neurologic deficits. Radiographically, DISH is characterized by flowing ossifications along the anterior spine spanning ≥4 vertebral bodies. Although the etiology of DISH remains unknown, diabetes mellitus and other metabolic derangements are strongly associated with DISH. Importantly, spinal ankylosis in DISH predisposes patients to unstable spine fractures from low-energy trauma, and careful consideration must be taken in managing these patients. This article reviews the epidemiology and pathophysiology of DISH, and its clinical findings, diagnostic criteria, and management.

Identifying Clinicoradiological Phenotypes in Diffuse Idiopathic Skeletal Hyperostosis: A Cross-Sectional Study

Background and objectives: Diffuse idiopathic skeletal hyperostosis (DISH) is a bone formation disease in which only skeletal signs are considered in classification criteria. The aim of the study was to describe different phenotypes in DISH patients based on clinicoradiological features. Materials and Methods: We evaluated 97 patients who met the Resnick or modified Utsinger classification criteria for DISH and were diagnosed at our hospital from 2004 to 2015. Patients were stratified into: (a) peripheral pattern (PP)—Resnick criteria not met but presenting ≥3 peripheral enthesopathies; (b) axial pattern (AP)—Resnick criteria met but <3 enthesopathies; and (c) mixed pattern (MP)—Resnick criteria met with ≥3 enthesopathies. Statistical analysis was carried out to identify variables that might predict classification in a given group. Results: Fifty-six of the 97 patients included (57.7%) were male and 72.2% fulfilled the Resnick criteria. Applying our classification, 39.7% were stratified as MP, 30.9% as AP and 29.4% as PP. Clinical enthesopathy was reported in 40.2% of patients during the course of the disease. Sixty-eight patients were included in a comparative analysis of variables between DISH patterns. The results showed a predominance of women (p < 0.004), early onset (p < 0.03), hip involvement (p < 0.003) and enthesitis (p < 0.001) as hallmarks of PP. Asymptomatic patients were most frequently observed in AP (28.6%, MP 3.8%, PP 5.0%) while MP was characterized by a more extensive disease. Conclusions: We believe DISH has distinct phenotypes and describe a PP phenotype that is not usually considered. Extravertebral manifestations should be included in the new classification criteria in order to cover the entire spectrum of the disease.

Diffuse Idiopathic Skeletal Hyperostosis of Cervical Spine with Dysphagia-Molecular and Clinical Aspects

Diffuse idiopathic skeletal hyperostosis (DISH) is a condition characterized by the calcification and ossification of the ligaments of the cervical spine; in some cases, it may result in dysphagia. The condition is more common in men over 50 years of age with metabolic disorders, and it is often asymptomatic and not a major issue for patients. The etiology of DISH is poorly understood, and known genetic factors indicate multiple signal pathways and multigene inheritance. In this review, we discuss the epidemiological, clinical, and etiological aspects of DISH with a special focus on dysphagia.

Scoring Osteoarthritis Reliably in Large Joints and the Spine Using Whole-Body CT: OsteoArthritis Computed Tomography-Score (OACT-Score)

A standardized method to assess structural osteoarthritis (OA) burden thorough the body lacks from literature. Such a method can be valuable in developing personalized treatments for OA. We developed a reliable scoring system to evaluate OA in large joints and the spine-the OsteoArthritis Computed Tomography (OACT) score, using a convenience sample of 197 whole-body low-dose non-contrast CTs. An atlas, containing example images as reference points for training and scoring, are presented. Each joint was graded between 0-3. The total OA burden was calculated by summing scores of individual joints. Intra- and inter-observer reliability was tested 25 randomly selected scans (N = 600 joints). Intra-observer reliability and inter-observer reliability between three observers was assessed using intraclass correlation coefficient (ICC) and square-weighted kappa statistics. The square-weighted kappa for intra-observer reliability for OACT-score at joint-level ranged from 0.79 to 0.95; the ICC for the total OA grade was 0.97 (95%-CI, 0.94 to 0.99). Square-weighted kappa for interobserver reliability ranged from 0.48 to 0.95; the ICC for the total OA grade was 0.95 (95%-CI, 0.90 to 0.98). The OACT score, a new reproducible CT-based grading system reflecting OA burden in large joints and the spine, has a satisfactory reproducibility. The atlas can be used for research purposes, training, educational purposes and systemic grading of OA on CT-scans.

Diffuse idiopathic skeletal hyperostosis: Etiology and clinical relevance

Diffuse idiopathic skeletal hyperostosis (DISH) is a systemic bone-forming condition characterized by the presence of at least three bony bridges at the anterolateral spine. The aim of this review was to address the present state of pathophysiological knowledge, the clinical relevance, and diagnosis of DISH. The pathogenesis of DISH is currently unknown. The presence of DISH has been associated with older age, male sex, obesity, hypertension, atherosclerosis, and diabetes mellitus. Because the new bone forms mainly at entheseal sites, local fibroblasts, chondrocytes, collagen fibers, and calcified matrix are probably influenced by genetic, vascular, metabolic, and mechanical factors. Diagnosing the presence of DISH is of clinical importance, because the risk of a spinal fracture increases and associations with the metabolic syndrome, coronary and aortic disease, and respiratory effects are strong. Unravelling the pathogenesis of DISH can impact the field of regenerative medicine and bone tissue regeneration.

Back to the beginning: Identifying lesions of diffuse idiopathic skeletal hyperostosis prior to vertebral ankylosis

OBJECTIVE

To better understand the pathogenesis of DISH, identifying early or pre-DISH lesions in the spine and investigating the relationship between spinal and extra-spinal manifestations of DISH.

MATERIAL

44 skeletonized individuals with DISH from the WM Bass Donated Skeletal Collection.

METHODS

For each vertebra, location, extension, point of origin and appearance of vertebral outgrowths were recorded. The size of the enthesophytes at the olecranon process, patella and calcaneal tuberosity was measured with digital callipers.

RESULTS

At either end of the DISH-ankylosed segment, isolated vertical outgrowths arising from the central third of the anterior aspect of the vertebral body can usually be observed. These bone outgrowths show a well-organized external cortical layer, an internal structure of trabecular bone and usually are unaccompanied by or show minimal associated endplate degeneration. Analysis of the relationship between spinal and extra-spinal manifestations (ESM) suggests great inter-individual variability. No correlation between any ESM and the stage of spinal DISH was found.

CONCLUSIONS

Small isolated outgrowths represent the earliest stages of the spinal manifestations of DISH. The use of ESM as an indicator of DISH should be undertaken with great caution until the relationship between these two features is understood.

SIGNIFICANCE

Improved accuracy of paleopathological diagnostic criteria of DISH.

LIMITATIONS

Small sample comprised of only individuals with DISH. FUTURE RESEARCH: micro-CT analysis to investigate the internal structure of the spinal lesions. Analysis of extra-spinal enthesophytes in individuals with and without DISH to understand their pathogenesis and association with the spinal lesions in individuals with DISH.

Enthesopathy of the anterior chest wall joints in patients with diffuse idiopathic skeletal hyperostosis (DISH): a retrospective analysis of computed tomography scans

PURPOSE

To evaluate and characterize anterior chest wall (ACW) joint's enthesopathy on CT scans in patients with DISH compared with age- and gender-matched control group.

MATERIAL AND METHODS

Retrospective evaluation for enthesopathy features of ACW joints-sterno-clavicular (SCJ), manubrio-sternal (MSJ), costo-sternal 1-7 (CSJ)-on chest CT scans of subjects with DISH (Resnick criteria) and of age- and gender-matched control subjects was performed. 183 subjects (DISH: 92, control: 91); male:female: 126:57, average age: 71.7 years (range 50-94) were evaluated. Total enthesopathy scores per subjects and per each joint were compared.

RESULTS

Total enthesopathy score of ACW joints was significantly higher among DISH compared to controls (64.03 ± 15.1, 50.47 ± 12.4, p < 0.001). At joint level, SCJ and CSJ enthesopathy, but not MSJ was significantly more prevalent in DISH compared to controls.

CONCLUSION

ACW joints' enthesopathy as seen on CT scans, an entity not included in the Resnick classification criteria, is common among DISH subjects. The difference between SCJ and CSJ prevalence compared to MSJ may result from different joint type. ACW joints' enthesopathy may be considered to be included in future modified radiographic criteria for DISH.