The Natural Course of Diffuse Idiopathic Skeletal Hyperostosis in the Thoracic Spine of Adult Males

Prevalence and characteristics of osseous bridging between vertebral bodies in the cervical spine: A skeletal study

Osseous bridging (OB) in three or more segments of motions (SOMs) of the mobile spine was initially defined as diffuse idiopathic skeletal hyperostosis (DISH), located particularly in the thoracic spine (T-spine). This pathological phenomenon is often characterized by calcification and ossification, which take place simultaneously or separately. The soft tissues, mainly ligaments and entheses, are calcified, with bone formation not originating from the anterior longitudinal ligament (ALL). DISH formation can involve osteophytes, which are created by the ossification process and can involve soft tissue such as the ALL. The ALL can also be calcified. Until recently, the prevalence of DISH in the general population was considered low (0%-5%) and rare in the cervical spine (C-spine). In a cross-sectional observational skeletal study, we investigated the prevalence and location of C-spine OB between vertebral bodies with fewer than three SOMs. We tested a large sample (n = 2779) of C-spines housed in the Cleveland Museum of Natural History (Ohio, USA). The human sources of the samples had died between the years 1912 and 1938 and represented both sexes and two different ethnic groups: Black Americans and White Americans. The process development can be seen on the ALLs as calcification, osteophytosis, and candle-shaped. Among all of the specimens, 139 (5%) were affected by OB, mostly in one SOM. Prevalence tended to be higher in women, White Americans, and the older age group. The levels most affected were C3-C4, followed by C2-C3 and subsequently, C5-C6. OB involving two consecutive SOMs was found only at C5-C7. We believe it is important to respond to the presence of a single SOM with a presumptive diagnosis of OB and to follow up, identify whether the diagnosis is correct, and take preventive action if possible. There is a need for updated diagnostic criteria and research approaches that reflect contemporary lifestyle factors and their impact on spine health.

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.

Surgical outcomes of anterior column reconstruction for spinal fractures caused by minor trauma-preoperative examination of the number of intervertebral bone bridges is key to obtaining good bone fusion

BACKGROUND

To achieve good bone fusion in anterior column reconstruction for vertebral fractures, not only bone mineral density (BMD) and bone metabolism markers but also lever arms due to bone bridging between vertebral bodies should be evaluated. However, until now, no lever arm index has been devised. Therefore, we believe that the maximum number of vertebral bodies that are bony and cross-linked with the contiguous adjacent vertebrae (maxVB) can be used as a measure for lever arms. The purpose of this study is to investigate the surgical outcomes of anterior column reconstruction for spinal fractures and to determine the effect of bone bridging between vertebral bodies on the rate of bone fusion using the maxVB as an indicator of the length of the lever arm.

METHODS

The clinical data of 81 patients who underwent anterior column reconstruction for spinal fracture between 2014 and 2022 were evaluated. The bone fusion rate, back pain score, between the maxVB = 0 and the maxVB ≥ 2 patients were adjusted for confounding factors (age, smoking history, diabetes mellitus history, BMD, osteoporosis drugs, surgical technique, number of fixed vertebrae, materials used for the anterior props, etc.) and analysed with multivariate or multiple regression analyses. The bone healing rate and incidence of postoperative back pain were compared among the three groups (maxVB = 0, 2≦maxVB≦8, maxVB ≧ 9) and divided by the maxVB after adjusting for confounding factors.

RESULTS

Patients with a maxVB ≥ 2 had a significantly higher bone fusion rate (p < 0.01) and postoperative back pain score (p < 0.01) than those with a maxVB = 0. Among the three groups, the bone fusion rate and back pain score were significantly higher in the 2≦maxVB≦8 group (p = 0.01, p < 0.01).

CONCLUSIONS

Examination of the maxVB as an indicator of the use of a lever arm is beneficial for anterior column reconstruction for vertebral fractures. Patients with no intervertebral bone bridging or a high number of bone bridges are in more need of measures to promote bone fusion than patients with a moderate number of bone bridges are.

Examining the Association Between the Extent of Anterior Longitudinal Ligament Ossification Progression and Comorbidities in Diffuse Idiopathic Skeletal Hyperostosis

BACKGROUND

 It has been documented that diffuse idiopathic skeletal hyperostosis (DISH) exhibits a higher prevalence among elderly, male, and obese individuals. Additionally, diabetes mellitus and other comorbidities are more frequently observed in this patient population. However, there is a lack of reports exploring the correlation between the extent of ossification and these demographic and clinical characteristics.

OBJECTIVE

To examine the correlation between comorbidities and the severity of ossification of the anterior longitudinal ligament in patients with DISH.

MATERIALS AND METHODS

The study included 468 patients who visited our hospital in 2018-2022. They were divided into DISH and non-DISH groups based on computed tomography image evaluation according to the Resnick criteria. The patients in the two groups were matched for age and sex. We compared comorbidity-related factors including body mass index (BMI), serum markers for metabolic syndrome and renal function, and hemoglobin A1c (HbA1c) levels between the matched groups. Moreover, we examined the correlation between the number of fused vertebral bodies and comorbidity-related factors, age, and sex within the DISH group.

RESULTS

The DISH group included significantly more men and elderly patients than the non-DISH group. Furthermore, the average BMI and HbA1c levels were significantly higher in the matched-DISH group than in the matched-non-DISH group, whereas no differences were observed in other markers. In the DISH group, the number of fused vertebral bodies did not correlate with age, sex, BMI, or HbA1c levels.

DISCUSSION

BMI and HbA1c levels were significantly higher in patients with DISH than those without; however, the number of fused vertebral bodies and the possibility of having coexisting obesity or diabetes mellitus showed no correlation with the age or sex of the patient. Therefore, each patient should be carefully assessed for ossification severity regardless of age, sex, and the comorbidities they possess.

Not All Osteophytes Are Located on the Right Side of the Vertebrae in Diffuse Idiopathic Skeletal Hyperostosis: A Quantitative Analysis in Relation to the Position of Aorta

OBJECTIVE

Diffuse idiopathic skeletal hyperostosis (DISH) is characterized by osteophytes in the anterior vertebrae, and the presence of aorta may have an impact on their formation. However, the anatomical positional relationship between the aorta and osteophytes in patients with DISH remains controversial. This study aimed to evaluate the position of osteophytes in relation to aorta in DISH, and the influence of aortic pulsation on the formation of osteophytes from the perspective of morphology.

METHODS

We conducted a retrospective review of 101 patients diagnosed with DISH and symptomatic lumbar spinal stenosis between June 2018 and December 2021. A total of 637 segments with heterotopic ossification in DISH were used for quantitative measurements on CT scans. The Cartesian coordinate system was built up on the axial CT scans to reflect the relative position between aorta and osteophytes. Osteophytes were divided into adjacent aorta group (AD group) and non-adjacent aorta group (N-AD group). In terms of the morphology, osteophytes in the AD group were further divided into convex, flat, and concave types. The relative position between aorta and osteophytes, and the aorta-osteophyte distance and morphology of osteophytes were compared. Univariate analysis of variance was performed for multiple groups, and two independent-samples t-tests were used for two groups.

RESULTS

From T5 to L4, aorta gradually descended from left side to middle of vertebrae, and osteophytes gradually shifted from right side of vertebrae (T5-T10) to bilateral sides (T11-L4). Of 637 osteophytes in DISH, 60.1% (383/637) were in AD group, including convex type 0.6% (4/637), flat type 34.7% (221/637), and concave type 24.8% (158/637). The N-AD group accounted for 39.9% (254/637). Flat osteophytes were concentrated in T5-T12, while concave osteophytes in T11-L4. Overall, the aorta-osteophyte distance of concave type was significantly smaller than that of flat type.

CONCLUSION

Osteophytes are not always located on the right side of vertebrae, but move with the position of the descending aorta. Furthermore, the morphology of osteophytes varies by vertebral segment in DISH, which is related to aorta descending anteriorly in the spine.

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.

Number of contiguous vertebral cross-links in the spine indicates bone formation: a cross-sectional study

BACKGROUND

As an indicator to evaluate the risk of fracture in diffuse idiopathic skeletal hyperostosis, the maximum number of vertebral bodies' bone cross-linked with contiguous adjacent vertebrae (max VB) was developed. This study retrospectively investigates the relationship between max VB, bone mineral density (BMD), and bone metabolic markers (BMM).

METHODS

In this cross-sectional study (from April 2010 to January 2022), males (n = 114) with various max VB from the thoracic vertebra to the sacrum, measured using computed tomography scans, were selected to assess femur BMD and BMM. The association of max VB with the total type I procollagen N-terminal propeptide (P1NP), tartrate-resistant acid phosphatase 5b (TRACP-5b), and bone turnover ratio (BTR = TRACP-5b/P1NP) as well as its relationship with femur BMD with P1NP and TRACP-5b, were investigated. Furthermore, the relationship between P1NP and TRACP-5b was investigated.

RESULTS

P1NP increased in proportion to max VB and TRACP-5b increased in proportion to P1NP. Moreover, BTR was inversely proportional to max VB. Finally, femur BMD was inversely proportional to P1NP and TRACP-5b.

CONCLUSION

As max VB increased with P1NP-a potential osteogenesis indicator-and BTR was inversely proportional to max VB with compensatory TRACP-5b increase, max VB can be considered as a possible predictor of bone fusion.

Osteophyte Bridge Formation Correlates with Vascular Calcification and Cardiovascular Disease in Diffuse Idiopathic Skeletal Hyperostosis

Diffuse idiopathic skeletal hyperostosis (DISH) is a noninflammatory spondyloarthropathy characterized by ectopic calcification of spinal cord tissue. Its etiology is possibly polygenic. However, its pathogenesis and systemic effects remain unclear. Recent studies have reported a high prevalence of DISH in heart failure patients. The authors investigated how the incidence and severity of DISH are associated with vascular calcification and the occurrence of cardiovascular events. In this retrospective chart review study, 500 patients with cardiovascular disease who underwent surgery (cardiovascular events group) and 500 patients with non-cardiovascular disease who underwent computed tomography scans (non-cardiovascular events group) were randomly selected to investigate the degree of ossification of the anterior longitudinal ligament and the incidence of DISH. We found that the incidence of DISH was higher in patients with cardiovascular events and that patients with DISH had more calcification of the coronary arteries and aorta. Next, we examined the relationship between the degree of coronary and aortic calcification, the incidence of DISH, and the degree of ossification of the anterior longitudinal ligament in the non-cardiovascular event group. The prevalence of DISH in the cardiovascular and non-cardiovascular groups was 31.4% and 16.5%, respectively (p = 0.007). Aortic calcification and a predominant degree of vascular calcification with a certain level of ossification of the anterior longitudinal ligament suggest some correlation between DISH and cardiovascular events. This study is important in understanding the pathophysiology and pathogenesis of DISH.

Effects of Bone Cross-Link Bridging on Fracture Mechanism and Surgical Outcomes in Elderly Patients with Spine Fractures

STUDY DESIGN

This study adopted a cross-sectional study design.

PURPOSE

This study was designed to investigate the effects of bone cross-link bridging on fracture mechanism and surgical outcomes in vertebral fractures using the maximum number of vertebral bodies with bony bridges between adjacent vertebrae without interruption (maxVB).

OVERVIEW OF LITERATURE

The complex interplay of bone density and bone bridging in the elderly can complicate vertebral fractures, necessitating a better understanding of fracture mechanics.

METHODS

We examined 242 patients (age >60 years) who underwent surgery for thoracic to lumbar spine fractures from 2010 to 2020. Subsequently, the maxVB was classified into three groups: maxVB (0), maxVB (2-8), and maxVB (9-18), and parameters, including fracture morphology (new Association of Osteosynthesis classification), fracture level, and neurological deficits were compared. In a sub-analysis, 146 patients with thoracolumbar spine fractures were classified into the three aforementioned groups based on the maxVB and compared to determine the optimal operative technique and evaluate surgical outcomes.

RESULTS

Regarding the fracture morphology, the maxVB (0) group had more A3 and A4 fractures, whereas the maxVB (2-8) group had less A4 and more B1 and B2 fractures. The maxVB (9-18) group exhibited an increased frequency of B3 and C fractures. Regarding the fracture level, the maxVB (0) group tended to have more fractures in the thoracolumbar transition region. Furthermore, the maxVB (2-8) group had a higher fracture frequency in the lumbar spine area, whereas the maxVB (9-18) group had a higher fracture frequency in the thoracic spine area than the maxVB (0) group. The maxVB (9-18) group had fewer preoperative neurological deficits but a higher reoperation rate and postoperative mortality than the other groups.

CONCLUSIONS

The maxVB was identified as a factor influencing fracture level, fracture type, and preoperative neurological deficits. Thus, understanding the maxVB could help elucidate fracture mechanics and assist in perioperative patient management.

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.

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.

Imaging Characteristics of Diffuse Idiopathic Skeletal Hyperostosis: More Than Just Spinal Bony Bridges

Diffuse idiopathic skeletal hyperostosis (DISH) is a systemic condition characterized by new bone formation and enthesopathies of the axial and peripheral skeleton. The pathogenesis of DISH is not well understood, and it is currently considered a non-inflammatory condition with an underlying metabolic derangement. Currently, DISH diagnosis relies on the Resnick and Niwayama criteria, which encompass end-stage disease with an already ankylotic spine. Imaging characterization of the axial and peripheral skeleton in DISH subjects may potentially help identify earlier diagnostic criteria and provide further data for deciphering the general pathogenesis of DISH and new bone formation. In the current review, we aim to summarize and characterize axial and peripheral imaging findings of the skeleton related to DISH, along with their clinical and pathogenetic relevance.

Is spinal sagittal alignment of diffuse idiopathic skeletal hyperostosis relevant to thoracolumbar pain? A controlled study

OBJECTIVES

The extension of diffuse idiopathic skeletal hyperostosis (DISH) from the low thoracic spine to the lumbar spine result in adjustment of spinal sagittal alignment in surgical patients. The aim of this study was to investigate changes in sagittal alignment and back pain in the thoracolumbar spine in nonsurgical DISH and control participants selected from a radiological database.

METHODS

Participants in the DISH and the control group were selected by searching for "DISH or degenerative changes in the thoracic spine" in the radiology database of Taizhou Hospital between 2018 and 2021 using Resnick and Niwayama's criteria. The subjects with spinal tumors, previous spinal surgery, vertebral fractures, inflammatory diseases, poor-quality radiographs, or loss of follow-up were excluded. Demographic and clinical characteristics were recorded retrospectively via the hospital information system and telephone follow-up. Segmental disc angles (SDAs), lumbar lordosis (LL), and bridge scores were analyzed using images of three-dimensional CT.

RESULTS

The final participants consisted of 51 individuals with DISH (DISH group) and 102 individuals without DISH (control group). Depending on the presence of thoracolumbar pain, the DISH group was divided into the DISH group with thoracolumbar pain (DISH+Pain) and the DISH group without thoracolumbar pain (DISH-Pain). The LL and SDAs of T11-T12 and T12-L1 were significantly greater in the DISH group than in the control group. In addition, the SDA of L1-L2 was significantly smaller in the DISH+Pain group than in the DISH-Pain group, whereas there was no significant difference in lumbar lordosis between the DISH+Pain group and the DISH-Pain group. The bridge scores in DISH+Pain group was larger in T10-T11 (p = 0.01) and L1-L2 (p < 0.01) spine segments than those in DISH-Pain group.

CONCLUSION

The extension of DISH from thoracic to lumbar spine may increase lumbar lordosis and SDAs in the thoracolumbar spine. The DISH patients with more bony bridging and small L1-L2 SDA may be more likely have thoracolumbar pain. Adjustment of sagittal alignment of the spine in the development of DISH may be of clinical importance.

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.

Progression of Ossification of the Anterior Longitudinal Ligament Associated With Diffuse Idiopathic Skeletal Hyperostosis by Age: A Study of Computed Tomography Findings Over 5 Years

STUDY DESIGN

Observational study.

OBJECTIVE

To investigate whether the progression of anterior longitudinal ligament ossification varies by age among patients with diffuse idiopathic skeletal hyperostosis (DISH).

METHODS

Of the patients who underwent computed tomography (CT) of the thoracic to pelvic region at least twice from 2009 to 2018, 191 who underwent CT at an interval of 5 years and 0 months to 5 years and 2 months were enrolled (87 men and 104 women). Sex, age at the time of the first CT scan, the presence/absence of DISH, level of complete vertebral body fusion associated with DISH, and extent of ligament ossification using the modified Mata scoring system were investigated.

RESULTS

DISHs were detected in 53 (27.7%) of 191 patients. The score of ligament ossification increased over time in 35 (66%) of 53 patients; 93 intervertebral spaces were affected. The percentage of completely fused intervertebral spaces increased by 6.7% from 31.3% to 38.0% over time. The increase in score for all intervertebral spaces in individual patients was significantly greater in the ≤70 years old group (2.7 ± 2.8 points, n = 28) than in the ≥71 years old group (1.2 ± 1.4 points; n = 25; P = .028). The mean age of patients with a recorded score that increased by ≥1 point was 67.4 years and that of patients without any change in the score was 73.3 years (P = .036). Thus, patients with recorded changes in the score were younger.

CONCLUSION

During the approximately 5-year period, ossification progressed more in younger patients than in older patients.

Association of Continuous Vertebral Bone Bridges and Bone Mineral Density with the Fracture Risk in Patients with Diffuse Idiopathic Skeletal Hyperostosis

Study Design

Cross-sectional study.

Purpose

To examine whether the number of continuous vertebral bone bridges and bone mineral density (BMD) influence the fracture risk in diffuse idiopathic skeletal hyperostosis (DISH) patients.

Overview of Literature

Bone bridges connecting through the intervertebral body in DISH create long lever arms that can increase the risk of fractures from minor trauma. DISH patients have a BMD that is higher than or comparable to those of age-matched healthy subjects.

Methods

We examined the computed tomography scans from the thoracic vertebra to the sacrum used to diagnose DISH in 140 patients (98 men and 42 women; average age, 78.6 years). We compared patients who did (n=52) and did not have (n=88) fractures at the continuous vertebral bodies fused by bone bridges. The relationship between the vertebral fractures and the maximum number of vertebrae that are bony cross-linked with contiguous adjacent vertebrae (max VB) from the thoracic vertebra to the sacrum or from the lumbar vertebra to the sacrum and proximal femur BMD were analyzed using a logistic regression model.

Results

We found that after adjusting for the confounding factors, higher max VB, both from the thoracic vertebrae to the sacrum and the lumbar vertebrae to the sacrum, was associated with a higher risk of vertebral fractures. This difference was statistically significant. The risk was higher when only the lumbar vertebrae to the sacrum was considered (thoracic vertebrae to the sacrum: odds ratio, 1.21; p<0.05; lumbar vertebrae to the sacrum: odds ratio, 2.78; p<0.01). Moreover, low proximal femur BMD in DISH patients raises the fracture risk (odds ratio, 0.47; p<0.01).

Conclusions

Many continuous vertebral bone bridges, especially those that extend to the lumbar spine and low proximal femur BMD, are risk factors for fracture in DISH patients.

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.

[Differential diagnosis of axial spondyloarthritis-axSpA mimics]

The classification of axial spondyloarthritis (axSpA) comprises the classical ankylosing spondylitis (AS), which is characterized by already existing structural changes in the sacroiliac joints, and the so-called non-radiographic axSpA (nr-axSpA), in which by definition such changes are not present. This distinction is based on the ASAS classification criteria for axSpA, which are however not suitable for a diagnosis. According to the current classification, spondyloarthritis (SpA) includes axSpA, which can be associated with psoriasis and/or chronic inflammatory bowel diseases (CED), such as Crohn's disease and ulcerative colitis, and peripheral SpA, which is further divided into SpA associated with psoriasis, partially synonymous with psoriatic arthritis (PsA), reactive SpA, partially synonymous with reactive arthritis (ReA) and SpA associated with CED, partially synonymous with arthritis associated with CED (e.g. Crohn's disease, ulcerative colitis) and peripheral undifferentiated SpA, which by definition is not associated with any of the above. In this article only the most important differential diagnoses are discussed, i. e. diffuse idiopathic skeletal hyperostosis (DISH), fractures and infections in the axial skeleton. In addition, the frequency of certain musculoskeletal findings in the normal population examined by magnetic resonance imaging (MRI) are also discussed.

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

Background Diffuse idiopathic skeletal hyperostosis (DISH) is a condition characterized by the formation of new bone along the anterolateral spinal column at four adjacent vertebral bodies. Purpose To propose and validate criteria for the early phase of DISH by using CT data from two large-scale retrospective cohorts, each with 5-year follow-up. Materials and Methods For this retrospective study, CT data at baseline and follow-up in 1367 patients (cohort I) from 2004 to 2011 were evaluated by two observers to define no DISH, early-stage DISH, and definite DISH on the basis of interval development of consecutive complete or incomplete bone bridges. An independent group of 2267 participants from the COPDGene cohort from 2008 to 2016 was used to validate the early DISH criteria (cohort II). The sensitivity and specificity of early DISH criteria were based on findings in the last CT study as the reference standard by using a nested case-control design. κ Values were calculated between seven readers and with a 3-month interval for one reader. Results Cohort I consisted of 100% men, with a mean age of 60.0 years ± 5.6 (standard deviation) and a mean time between baseline and follow-up CT of 5.0 years ± 1.1. Cohort II consisted of 51% men, with a mean age of 59.9 years ± 8.6 and a mean time between baseline and follow-up CT of 5.4 years ± 0.5. In the derivation cohort, 55 patients comprised the early DISH group. Early DISH was defined as the presence of a spinal segment with a complete bone bridge with an adjacent segment of at least a near-complete bone bridge and another adjacent segment with at least the presence of newly formed bone or when three or more adjacent segments were recorded as showing a near-complete bone bridge. In the validation cohort, sensitivity for early DISH (vs no DISH) was 96% (99 of 103 participants; 95% confidence interval [CI]: 90%, 99%). The corresponding specificity was 83% (1695 of 2034 participants; 95% CI: 82%, 85%). The Fleiss κ for interrater reliability was 0.78 (95% CI: 0.77, 0.78), and the κ for intrarater reliability was 0.89 (95% CI: 0.82, 0.96). Conclusion Early diffuse idiopathic skeletal hyperostosis (DISH) criteria had high sensitivity and specificity for predicting the development of DISH. © RSNA, 2019 Online supplemental material is available for this article. See also the editorial by Block in this issue.

Ectopic spinal calcification associated with diffuse idiopathic skeletal hyperostosis (DISH): A quantitative micro-ct analysis

Diffuse idiopathic skeletal hyperostosis (DISH) is a non-inflammatory spondyloarthropathy identified radiographically by calcification of the ligaments and/or entheses along the anterolateral aspect of the vertebral column. The etiology and pathogenesis of calcifications are unknown, and the diagnosis of DISH is currently based on radiographic criteria associated with advanced disease. To characterize the features of calcifications associated with DISH, we used micro-computed tomographic imaging to evaluate a cohort of 19 human cadaveric vertebral columns. Fifty-three percent of the cohort (n = 10; 3 females, 7 males, mean age of death = 81 years, range 67-94) met the radiographic criteria for DISH, with calcification of four or more contiguous vertebral segments. In almost all cases, the lower thoracic regions (T8-12) were affected by calcifications, consisting primarily of large, horizontal outgrowths of bony material. In contrast, calcifications localized to the upper thoracic regions demonstrated variability in their presentation and were categorized as either "continuous vertical bands" or "discontinuous-patchy" lesions. In addition to the variable morphology of the calcifications, our analysis demonstrated remarkable heterogeneity in the densities of calcifications, ranging from internal components below the density of cortical bone to regions of hyper-dense material that exceeded cortical bone. These findings establish that the current radiographic criteria for DISH capture heterogeneous presentations of ectopic spine calcification that can be differentiated based on morphology and density. These findings may indicate a naturally heterogenous disease, potential stage(s) in the natural progression of DISH, or distinct pathologies of ectopic calcifications. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res.

Interobserver agreement using Schlapbach graded scale for diffuse idiopathic skeletal hyperostosis (DISH): can we reduce the cut-off point of vertebral affection?

Resnick-Niwayama criteria for diagnosing DISH depict an advanced stage, and a new reduced cut-off point with three contiguous vertebrae affected (two bone bridges) has been proposed. The aim has been to know the interobserver agreement by using a graded scale of DISH in which grade II matches with the new proposed cut-off point and grade III matches with the first criterion of Resnick-Niwayama. Males ≥ 50 years and postmenopausal women included in a population-based prospective study (the Camargo Cohort) were analyzed. Sample size was obtained according to an expected kappa of 0.95 and an accuracy of ± 8%. Three physicians applied independently Schlapbach graded scale (ranged from grade 0, no ossification, to grade III, ≥ 3 consecutive bone bridges) on the lateral radiographs of thoracic and lumbar spine of participants. We calculated inter- and intra-observer agreement and correlation. One hundred and fifty eight radiographs (79 patients, 68 ± 9 years) were assessed. Kappa values (95% confidence interval) for grades 0, I, II, and III were 0.63 (0.50-0.77), 0.49 (0.37-0.62), 0.32 (0.17-0.47), and 0.69 (0.60-0.77), respectively. Weighted kappa for the three pairs of raters were 0.87 (0.82-0.93), 0.84 (0.77-0.91), and 0.81 (0.72-0.90). Grade III was the image that generated greater agreement, while a significant decrease was noted in grade II, the new proposed criterion. The simultaneous presence of an incomplete DISH and osteoarthritis, in a thoracic spinal segment with peculiar anatomical characteristics (reduced disk spaces, kyphotic curve), is thought to be a major cause of variability in the results.

Bone mineral density changes over time in diffuse idiopathic skeletal hyperostosis of the thoracic spine

Diffuse idiopathic skeletal hyperostosis (DISH) is an increasingly prevalent ankylosing condition. Patients with DISH have an increased risk of spinal fractures, hypothetically the result of biomechanical changes in the spine. The aim of this study was to analyze the occurrence of biomechanical stress shielding in patients with DISH. To do this, bone mineral density (BMD) was measured longitudinally in the vertebral bodies of subjects with and without DISH and in the newly formed bone of subjects with DISH. The presence of DISH was evaluated using Resnick criteria on two chest computed tomography (CT) scans taken at least 2.5 years apart from subjects over 50 years of age. Three groups were identified: pre-DISH (individuals who developed DISH after the first CT scan), definite DISH (individuals who had DISH on both CT scans), and controls (individuals with no DISH). Hounsfield units (HU) were measured in the newly formed bone and in predefined anterior and posterior portions of the involved vertebral bodies. Mean BMD of the newly formed bone increased significantly (mean ΔHU 137.5; p < 0.01) during a mean interval of 5 years in the cranial, middle, and caudally involved vertebral segments of both DISH groups. Mean BMD of the vertebral bodies in the ankylotic segments in the DISH groups did not significantly differ from that of the non-ankylotic vertebral bodies of the same subject. In contrast to our hypothesis, the HU value of the vertebral body decreased more in the control group than in the DISH groups; however, statistical significance was only reached at the cranial level in the anterior part of the vertebral body (p = 0.048). Our data suggest that 1) vertebral BMD is not influenced by the presence of DISH and 2) increased spinal stiffness may play a more important role than vertebral BMD in the increased fracture risk of and the typical fracture patterns observed in individuals with DISH.