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.

Inducing Angiogenesis in the Nucleus Pulposus

Bone morphogenetic protein (BMP) gene delivery to Lewis rat lumbar intervertebral discs (IVDs) drives bone formation anterior and external to the IVD, suggesting the IVD is inhospitable to osteogenesis. This study was designed to determine if IVD destruction with a proteoglycanase, and/or generating an IVD blood supply by gene delivery of an angiogenic growth factor, could render the IVD permissive to intra-discal BMP-driven osteogenesis and fusion. Surgical intra-discal delivery of naïve or gene-programmed cells (BMP2/BMP7 co-expressing or VEGF165 expressing) +/- purified chondroitinase-ABC (chABC) in all permutations was performed between lumbar 4/5 and L5/6 vertebrae, and radiographic, histology, and biomechanics endpoints were collected. Follow-up anti-sFlt Western blotting was performed. BMP and VEGF/BMP treatments had the highest stiffness, bone production and fusion. Bone was induced anterior to the IVD, and was not intra-discal from any treatment. chABC impaired BMP-driven osteogenesis, decreased histological staining for IVD proteoglycans, and made the IVD permissive to angiogenesis. A soluble fragment of VEGF Receptor-1 (sFlt) was liberated from the IVD matrix by incubation with chABC, suggesting dysregulation of the sFlt matrix attachment is a possible mechanism for the chABC-mediated IVD angiogenesis we observed. Based on these results, the IVD can be manipulated to foster vascular invasion, and by extension, possibly osteogenesis.

Stiffness and axial pain are associated with the progression of calcification in a mouse model of diffuse idiopathic skeletal hyperostosis

BACKGROUND

Diffuse idiopathic skeletal hyperostosis (DISH) is characterized by progressive calcification of spinal tissues; however, the impact of calcification on pain and function is poorly understood. This study examined the association between progressive ectopic spine calcification in mice lacking equilibrative nucleoside transporter 1 (ENT1^-/-), a preclinical model of DISH, and behavioral indicators of pain.

METHODS

A longitudinal study design was used to assess radiating pain, axial discomfort, and physical function in wild-type and ENT1^-/- mice at 2, 4, and 6 months. At endpoint, spinal cords were isolated for immunohistochemical analysis of astrocytes (GFAP), microglia (IBA1), and nociceptive innervation (CGRP).

RESULTS

Increased spine calcification in ENT1^-/- mice was associated with reductions in flexmaze exploration, vertical activity in an open field, and self-supporting behavior in tail suspension, suggesting flexion-induced discomfort or stiffness. Grip force during the axial stretch was also reduced in ENT1^-/- mice at 6 months of age. Increased CGRP immunoreactivity was detected in the spinal cords of female and male ENT1^-/- mice compared to wild-type. GFAP- and IBA1-immunoreactivity were increased in female ENT1^-/- mice compared to wild-type, suggesting an increase in nociceptive innervation.

CONCLUSION

These data suggest that ENT1^-/- mice experience axial discomfort and/or stiffness and importantly that these features are detected during the early stages of spine calcification.

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.

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.

Less-invasive decompression procedures can reduce risk of reoperation for lumbar spinal stenosis with diffuse idiopathic skeletal hyperostosis extended to the lumbar segment: analysis of two retrospective cohorts

PURPOSE

Clinical outcomes after decompression procedures are reportedly worse for lumbar spinal stenosis (LSS) with diffuse idiopathic skeletal hyperostosis (DISH), especially DISH extended to the lumbar segment (L-DISH). However, no studies have compared the effect of less-invasive surgery versus conventional decompression techniques for LSS with DISH. The purpose of this study was to compare the long-term risk of reoperation after decompression surgery focusing on LSS with L-DISH.

METHODS

This study compared open procedure cohort (open conventional fenestration) and less-invasive procedure cohort (bilateral decompression via a unilateral approach) with ≥ 5 years of follow-up. After stratified analysis by L-DISH, patients with L-DISH were propensity score-matched by age and sex.

RESULTS

There were 57 patients with L-DISH among 489 patients in the open procedure cohort and 41 patients with L-DISH among 297 patients in the less-invasive procedure cohort. The reoperation rates in L-DISH were higher in the open than less-invasive procedure cohort for overall reoperations (25% and 7%, p = 0.026) and reoperations at index levels (18% and 5%, p = 0.059). Propensity score-matched analysis in L-DISH demonstrated that open procedures were significantly associated with increased overall reoperations (hazard ratio [HR], 6.18; 95% confidence interval [CI], 1.37-27.93) and reoperations at index levels (HR, 4.80; 95% CI, 1.04-22.23); there was no difference in reoperation at other lumbar levels.

CONCLUSIONS

Less-invasive procedures had a lower risk of reoperation, especially at index levels for LSS with L-DISH. Preserving midline-lumbar posterior elements could be desirable as a decompression procedure for LSS with L-DISH.

Association of Inflammation, Ectopic Bone Formation, and Sacroiliac Joint Variation in Ossification of the Posterior Longitudinal Ligament

Ossification of the posterior longitudinal ligament (OPLL) is considered a multifactorial condition characterized by ectopic new bone formation in the spinal ligament. Recently, its connections with inflammation as well as sacroiliac (SI) joint ankylosis have been discussed. Nevertheless, whether inflammation, spinal ligament ossification, and SI joint changes are linked in OPLL has never been investigated. In this study, whole-spinal computed tomography and serum high-sensitive C-reactive protein (hs-CRP) levels were obtained in 162 patients with cervical OPLL. Ossification lesions were categorized as plateau and hill shapes. Accordingly, patients were divided into plateau-shaped (51 males and 33 females; mean age: 67.7 years) and hill-shaped (50 males and 28 females; mean age: 67.2 years) groups. SI joint changes were classified into four types and three subtypes, as previously described. Interactions among ossification shapes, hs-CRP levels, and morphological changes in the SI joint were investigated. The plateau shape was more common in the vertebral segments (59.5%), compared to the hill shape, which was predominant in the intervertebral regions (65.4%). Serum hs-CRP levels in the plateau-shaped group (0.11 ± 0.10 mg/dL) were significantly higher than those in the hill-shaped group (0.07 ± 0.08 mg/dL). SI joint intra-articular fusion was the main finding in the plateau-shaped group and showed significantly higher hs-CRP levels compared to the anterior para-articular bridging, which more frequently occurred in the hill-shaped group. Our findings suggested a possible inflammation mechanism that might contribute to the new bone formation in OPLL, particularly the plateau shape.

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.

Impact of Diffuse Idiopathic Skeletal Hyperostosis on Clinico-Radiological Profiles and Prognosis for Thoracic Ossification of Ligamentum Flavum-Myelopathy: A Propensity-Matched Monocentric Analysis

Background: Diffuse idiopathic skeletal hyperostosis (DISH) has been evaluated as a potential risk factor of poor surgical outcomes for lumbar spinal stenosis, whereas the influence of DISH on neuroimaging characteristics and postoperative prognosis of patients with thoracic myelopathy has not been established. Therefore, this study aimed to shed light on this issue. Methods: A monocentric study enrolled 167 eligible patients with thoracic ossification of ligamentum flavum (TOLF), who were followed up for at least 2 years. Clinico-radiological parameters and surgical outcomes were compared between the DISH+ and DISH− groups before and after propensity matching. Subgroup analysis was conducted to compare the functional outcomes between mild DISH (M-DISH) and moderately severe DISH (MS-DISH) groups. Results: Fifty-eight patients were diagnosed as DISH, and its prevalence was 34.7%. Patients with DISH presented with older age, more males, taller stature, heavier weight, more commonly diffuse-type TOLF (p < 0.05). The DISH group showed significantly worse recovery rate (RR) at the final follow-up before and after propensity matching (p < 0.01), and slightly lower preoperative VAS, higher postoperative VAS and lower VAS reduction, despite not reaching the significant differences. Subgroup analysis demonstrated that the M-DISH group was associated with the lower mJOA score (p = 0.01) and RR at the final follow-up (p = 0.001), and tended to present higher preoperative VAS than the MS-DISH group. Conclusions: DISH has a significant predisposition to the elderly males with diffuse-type TOLF. Although the presence of M-DISH might bring about a suboptimal surgical outcome, both DISH and non-DISH patients experienced good neurological function improvements and pain relief through thoracic posterior decompression.

An isotope signature for diffuse idiopathic skeletal hyperostosis?

OBJECTIVES

Diffuse idiopathic skeletal hyperostosis (DISH) has recurrently been associated with a rich diet (high in protein and higher trophic level foods); however, very few studies have investigated this link using carbon and nitrogen (δ¹³C and δ¹⁵N) stable isotope analysis. This paper explores the relationship between DISH and diet in two Roman urban communities by analyzing individuals with and without DISH.

MATERIALS AND METHODS

δ¹³C and δ¹⁵N analysis carried out on collagen from 33 rib samples (No DISH: 27; early DISH: 4; DISH: 2) selected from individuals buried at the Romano-British site of Baldock (UK), 41 rib samples (No DISH: 38; early DISH: 3) from individuals from the Catalan Roman site of Santa Caterina (Barcelona, Spain). Additionally, six faunal samples from Baldock and seven from Santa Caterina were analyzed.

RESULTS

Standardized human isotope data from Santa Caterina show high δ¹⁵N probably associated to a diet combining terrestrial resources and freshwater fish. In contrast, isotope results from Baldock suggest a terrestrial-based diet. Individuals with DISH do not show isotopic ratios indicative of rich diet and there is no correlation between stage of DISH development and δ¹³C and δ¹⁵N.

CONCLUSION

The results of this study suggest that individuals with DISH followed a similar or isotopically similar diet as those individuals without DISH in Baldock and in Santa Caterina and therefore, while DISH may have been influenced by individual's dietary habits, this is not reflected in their isotopic signature.

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.

Differences between diffuse idiopathic skeletal hyperostosis and spondyloarthritis

Diffuse idiopathic skeletal hyperostosis (DISH) is a skeletal syndrome that has been known for more than 70 years. Yet, its pathogenesis and treatment options are still under investigation. DISH and spondyloarthritidies may manifest itself clinically as very similar disorders causing impaired axial flexibility, axial pain and peripheral tendinopathies. On the other hand, these two processes are different in many ways, from different genetic and metabolic predispositions, to different clinical and imaging manifestations, and at last, a different attitude toward treatment. The knowledge of the similarities and differences between DISH and spondyloarthritidies can guide the clinician toward a better diagnostic and treatment approach. This review tries to emphasize these details.

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.

CT-Based Evaluation of Diffuse Idiopathic Skeletal Hyperostosis in Adult Population; Prevalence, Associations and Interobserver Agreement

Diffuse idiopathic skeletal hyperostosis (DISH), being an asymptomatic condition, is generally discovered incidentally on imaging and it has not received much attention for research on clinical grounds. We assessed the prevalence of DISH, its associated factors, and interobserver agreement for computed tomography (CT)-based diagnosis of DISH. CT scans of chest, abdomen, and pelvis performed for various clinical indications were retrospectively reviewed. Resnick criteria were used for the diagnosis of DISH. Moreover, enthesopathy along with comorbidities was assessed. CT scans were observed by 3 observers having different experience levels. Out of total 416 patients, the prevalence of DISH was 30.8%. Strong positive agreement was observed between observer 1 and 2 (k = 0.89), observer 1 and 3 (k = 0.91), and observer 2 and 3 (k = 0.94). Reporting rate of DISH was 59.3%. Regression analyses showed that enthesopathy was 2.45 times (adjusted odds ratio [AOR]: 2.45, 95% confidence intervals [CI]: 1.48-4.05), diabetic patients were 4.74 times (AOR: 4.74, 95% CI: 2.89-7.78) while hypertensive patients were 2.17 times (AOR: 2.17, 95% CI: 1.30-3.62) more likely to have DISH in comparison to those who do not have DISH. A high prevalence of DISH was observed in our cohort. Enthesopathy and comorbidities like diabetes and hypertension were significant factors associated with DISH. Moreover, excellent agreement was observed in defining DISH on CT according to Resnick criteria.

Diffuse idiopathic skeletal hyperostosis in a 33-year-old woman with PCOS and metabolic syndrome: a rare scenario

Diffuse idiopathic skeletal hyperostosis (DISH) is a common degenerative enthesopathy seen in the elderly with male preponderance. It is uncommon in patients before 50 years of age and is extremely rare in patients younger than 40 years. We report a case of 33-year-old unmarried woman who presented with inflammatory spinal pain and stiffness, limited chest expansion, decreased range of spinal motion and postural abnormalities, all of which suggested the diagnosis of ankylosing spondylitis, considering the patient's age. But, further evaluation led us to the final diagnosis of DISH with associated metabolic syndrome and polycystic ovarian syndrome (PCOS). To the best of our knowledge, our patient is the first reported case of DISH in a woman less than 40 years of age, and also the first case of DISH associated with PCOS and metabolic syndrome.

Progressive diffuse idiopathic spinal hyperostosis: a case report

Diffuse idiopathic spinal hyperostosis (DISH) causes various problems, such as adjacent disc dysfunction, pseudarthrosis, or reossification, when spinal surgery is performed or spinal fracture occurs. The authors herein describe a patient with DISH in whom ossification of the anterior longitudinal ligament progressively advanced from the thoracic to sacral vertebrae during a 14-year period. Surgery was performed three times to treat the characteristic problems associated with DISH: abnormal sagittal alignment of the spine, ossification of the posterior longitudinal ligament, reossification of the laminectomy-treated regions and accompanying spinal canal stenosis, pseudarthrosis after spinal fracture, and delayed palsy. DISH-associated problems after spinal fusion are not rare, but this patient developed a particularly large number of problems often seen in the long term after spinal fusion in patients with DISH. Clinicians must be aware of problems being likely to occur in ossification-discontinuous and fragile regions during the postoperative follow-up.

Spinal fractures in patients with Diffuse idiopathic skeletal hyperostosis:A nationwide multi-institution survey

BACKGROUND

Diffuse idiopathic skeletal hyperostosis (DISH) increases the spine's susceptibility to unstable fractures that can cause neurological deterioration. However, the detail of injury is still unclear. A nationwide multicenter retrospective study was conducted to assess the clinical characteristics and radiographic features of spinal fractures in patients with DISH.

METHODS

Patients were eligible for this study if they 1) had DISH, defined as flowing ossification along the anterolateral aspect of at least four contiguous vertebral bodies, and 2) had an injury in the ankylosing spine. This study included 285 patients with DISH (221 males, 64 females; mean age 75.2 ± 9.5 years).

RESULTS

The major cause of injury was falling from a standing or sitting position; this affected 146 patients (51.2%). Diagnosis of the fracture was delayed in 115 patients (40.4%). Later neurological deterioration by one or more Frankel grade was seen in 87 patients (30.5%). The following factors were significantly associated with neurological deficits: delayed diagnosis (p = 0.033), injury of the posterior column (p = 0.021), and the presence of ossification of the posterior longitudinal ligament (OPLL) (p < 0.001). The majority of patients (n = 241, 84.6%) were treated surgically, most commonly by conventional open posterior fixation (n = 199, 69.8%). Neurological improvement was seen in 20.0% of the conservatively treated patients, and in 47.0% of the patients treated surgically.

CONCLUSIONS

Minor trauma could cause spinal fractures in DISH patients. Delayed diagnosis, injury of the posterior column, and the presence of OPLL were significantly associated with neurological deterioration. Patients with neurological deficits or unstable fractures should be treated by fixation surgery.

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.

Aortic pulsation prevents the development of ossification of anterior longitudinal ligament toward the aorta in patients with diffuse idiopathic skeletal hyperostosis (DISH) in Japanese: Results of chest CT-based cross-sectional study

BACKGROUND

The development and etiology of diffuse idiopathic skeletal hyperostosis (DISH) were far from complete understanding. Even the precise mechanism of the development of its typical right-sided ossification of the anterior longitudinal ligament (OALL) frequently compared to 'flowing candle wax', a hallmark of DISH, remains unknown.

METHODS

The participants of this study were 261 individuals (31 females and 230 males) diagnosed as DISH according to the criteria established by Resnick and Niwayama extracted from a consecutive 3013 patients who have undergone chest CT for the examination of pulmonary diseases in our institute. The patients with previous thoracic spine surgery and younger than 15 years old were excluded. Chest CT data were converted to the condition suitable for bone evaluation by the software application. The positional relationship between thoracic aorta and OALL, the morphology of the OALL adjacent to the aorta and the presence of calcification of the aortic wall adjacent to the OALL were studied.

RESULTS

Of 261 individuals with DISH, we found that thoracic aorta was localized adjacent to the OALL (AD-group) in 123 cases (47%), whereas 138 cases (53%) were not (NAD-group). All OALL in AD-group was localized between T6 and T12. The shape of the OALL adjacent to the aorta was either flat or concave except for one. No case showed obvious calcification of the aortic wall adjacent to the OALL in AD-group.

CONCLUSIONS

The aortic pulsation might play an important role in inhibit the development of the OALL toward the aorta in DISH. It is likely that establishment of the optimal condition of the pulsation stress simulating aortic pulsation and its delivery system can achieve arresting, slowing the progression and/or changing the morphology of the ossified lesions.

Diffuse idiopathic skeletal hyperostosis is associated with lumbar spinal stenosis requiring surgery

Factors related to the onset and progression of lumbar spinal stenosis (LSS) have not yet been identified. Diffuse idiopathic skeletal hyperostosis (DISH) increases mechanical loading on the non-fused lumbar levels and may therefore lead to LSS. This cross-sectional study aimed to identify associations between LSS and DISH. This study included 2363 consecutive patients undergoing surgery for LSS and 787 general inhabitants without symptoms of LSS as participants of the population-based cohort study, Research on Osteoarthritis/Osteoporosis Against Disability. Standing whole-spine radiographs were used to diagnose DISH based on the criteria proposed by Resnick and Niwayama. The prevalence of DISH showed a significant step-wise increase among asymptomatic inhabitants without radiographic LSS, asymptomatic inhabitants with radiographic LSS, and patients with LSS requiring surgery (14.4, 21.1, and 31.7%, respectively; p < 0.001). The distribution of DISH was similar between the groups, but the lower thoracic and upper-middle lumbar spine regions were more frequently involved in patients with LSS requiring surgery. Multivariate analysis indicated that DISH was an independent associated factor for LSS requiring surgery (adjusted odds ratio 1.65; 95% confidence interval 1.32-2.07) after adjustment for age, sex, body mass index, and diabetes mellitus. Among patients with LSS requiring surgery, a higher occurrence of stenosis at the upper lumbar levels and multi-level stenosis were observed in patients with DISH requiring surgery than in patients without DISH. In conclusion, DISH is independently associated with LSS requiring surgery. The decrease in the lower mobile segments by DISH may increase the onset or severity of LSS.

Diffuse Idiopathic Skeletal Hyperostosis, Associated Morbidity, and Healthcare Utilization: A University Hospital Experience

BACKGROUND

Diffuse idiopathic skeletal hyperostosis (DISH) is a noninflammatory condition affecting the spine, characterized by ossification of paravertebral ligaments. Our cross-sectional study investigated the frequency, associated morbidity, and healthcare utilization of DISH patients at our university hospital over 1 year.

METHODS

Our university's database of spinal radiographs was searched from 2005 to 2015 for "DISH" or "diffuse idiopathic skeletal hyperostosis." The diagnosis of DISH was made by 2 board-certified radiologists (B.B. and C.Q.) based on the radiographs of cervical, thoracic, or lumbar spine. Patients from 2015 were further analyzed with regards to demographics, comorbidities, and healthcare interventions. Their spinal radiographs were reread by 2 authors. Patients were divided into those who fulfilled the Resnick criteria for DISH (group A), and those who did not fully meet the criteria but had radiographic features suggestive of DISH (group B). Means and proportions were used to describe variables. For group comparisons, t test and χ test were used.

RESULTS

Between 2005 and 2015, 3439 radiology records mentioned DISH as a diagnosis. Of 195 patients diagnosed with DISH in 2015, 153 were in group A, 41 were in group B, and 2 had erroneous diagnoses. Chronic back pain was common, and more often reported in group B than in group A (81% vs 63%, p = 0.04). Substantial portions of patients required opioid medications for pain control (51%), spinal surgery (31%), and consultations with various specialists for regional pain (57%).

CONCLUSIONS

Diffuse idiopathic skeletal hyperostosis is a diagnosis with significant morbidity, despite being commonly viewed as asymptomatic. A majority of DISH patients had chronic back pain, and a large proportion required spinal surgery, although there may be several confounders. Future research is needed to systematically assess healthcare utilization by DISH patients.

Degenerative changes of the thoracic spine do exist in patients with diffuse idiopathic skeletal hyperostosis: a detailed thoracic spine CT analysis

Background Degenerative intervertebral disease (DID) is an exclusion criterion in the Resnick and Niwayama radiographic classification for diffuse idiopathic skeletal hyperostosis (DISH). However, although DID was previously described in DISH, no systematic computed tomography (CT) analysis has been reported so far. Purpose To assess for the presence and prevalence of such changes on CT examinations of the thoracic spine of individuals with DISH. Material and Methods Intervertebral space (D1-L1) on chest CT examinations of DISH patients was retrospectively evaluated for the presence of DID. Parameters evaluated were disc space height, disc protrusion, subchondral cysts/sclerosis, Schmorl nodes, vacuum phenomenon, and posterior elements including costovertebral and facet joints. Parameters were compared with two age- and gender-matched control groups of individuals whose entire spine CT lacked evidence of DISH (Control 1 individuals < 2 flowing osteophytes, Control 2 individuals < 4 and ≥ 2 flowing osteophytes). Results A total of 158 participants (DISH/Control 1/Control 2 = 54/54/50; 106 men, 52 women; average age = 70.6 years) were evaluated. Average intervertebral disc height was significantly lower in the DISH group compared with both control groups (DISH/Control 1/Control 2 = 4.55/5.13/5.01 mm, P < 0.001). Costovertebral degenerative changes were more prevalent in DISH patients ( P < 0.05) and, except for vacuum phenomenon (more prevalent in controls), other DID changes were as prevalent in DISH as in controls. Conclusion The presence of degenerative intervertebral changes on thoracic CT should not deter from diagnosing DISH. Thus, the radiographic Resnick and Niwayama DISH criteria cannot be directly adapted to CT.

Diffuse Idiopathic Skeletal Hyperostosis Extended to the Lumbar Segment Is a Risk Factor of Reoperation in Patients Treated Surgically for Lumbar Stenosis

STUDY DESIGN

Retrospective longitudinal cohort study.

OBJECTIVE

To investigate the association between diffuse idiopathic skeletal hyperostosis (DISH) and reoperation in patients treated surgically for lumbar spinal stenosis (LSS) in long-term results.

SUMMARY OF BACKGROUND DATA

Few studies have evaluated DISH as a potential risk factor of poor surgical results for LSS.

METHODS

This study included 1063 responders to a postoperative postal survey out of 2363 consecutive patients who underwent surgery for LSS between 2002 and 2010. The survey included questions about reoperations performed at another hospital and the patient-reported outcomes. DISH was evaluated by preoperative standing whole-spine radiographs. We investigated DISH as a predictor of reoperation and characteristics of poor outcomes in patients with DISH. We also assessed selection bias by examining the differences between responders and nonresponders to a postal survey.

RESULTS

Reoperations were performed in a total of 115 patients (10.8%) within an average of 8.6 years after the initial surgeries. Patients who only had DISH were not associated with reoperation; however, reoperations were performed significantly more often in patients with DISH extended to the lumbar segment (L-DISH) than in patients without (22% and 7.3%, respectively; P < 0.001). Cox analysis showed that L-DISH was one of the significant independent predictors for reoperation (hazard ratio 2.05, P = 0.009). Surgery-free survival was significantly shorter in patients with L-DISH than in those without (P = 0.005). The cause of reoperation did not differ between the patients with and without L-DISH. Several factors, but not L-DISH, were significantly associated with responders to the survey.

CONCLUSION

L-DISH was independently associated with reoperation for LSS. The decreased number of lumbar mobile segments due to L-DISH might lead to unfavorable outcomes. Careful follow-up of patients is needed after surgery for LSS with L-DISH.

LEVEL OF EVIDENCE

3.

Abdominal fat distribution in diffuse idiopathic skeletal hyperostosis and ankylosing spondylitis patients compared to controls

AIM

To evaluate abdominal fat distribution (subcutaneous adipose tissue [SAT] and visceral adipose tissue [VAT]) in two enthesopathy-related diseases with known correlation to metabolic syndrome (MS): diffuse idiopathic skeletal hyperostosis (DISH) and ankylosing spondylitis (AS) compared with controls.

MATERIALS AND METHODS

Abdominal computed tomography (CT) examinations of 43 DISH (Resnick radiographic criteria) patients, 31 AS (Modified New York Criteria) patients and 42 age- and gender-matched (to DISH) controls (males: 29; 29; 27 and mean age: 71.7±7; 56.1±16; 72.7±8 years, respectively) were evaluated and compared for VAT and SAT surface areas on mid L3, L4, L5 levels.

RESULTS

AS patients were significantly younger compared to DISH patients and controls. No significant differences were observed between VAT and SAT of DISH and AS patients or between SAT values in all groups even after correction for age. VAT was higher in DISH and AS patients compared to controls on all three levels, but reached significance (p<0.05) only for DISH patients (L3: 24.34/23.6/18.43; L4: 23.85/22.21/18.05; L5: 19.09/18.94/14.24 mm², respectively). This did not change after correction for age. The VAT/SAT ratio was significantly larger in DISH and AS patients on all levels compared to controls.

CONCLUSION

The higher VAT surface area, a known marker for MS, which by itself is associated with bone proliferation, in DISH and AS patients compared to controls substantiates its role as a potential surrogate marker for MS as well as suggests a potential shared pathogenic pathway for enthesopathic excessive bone production in DISH and AS.

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

Objective.

Diffuse idiopathic skeletal hyperostosis (DISH) is characterized by flowing bony bridges on the right side of the spine. Knowledge of the development of these spinal bridges is limited. The current longitudinal computed tomography (CT) study was designed to bridge this gap.

Methods.

Chest CT scans from elderly males with 2 scans (interval ≥ 2.5 yrs) were retrospectively included. Using the Resnick criteria, a pre-DISH group and a definite DISH group were identified. A scoring system based on the completeness of a bone bridge (score 0–3), extent of fluency, and location of the new bone was created to evaluate the progression of bone formation.

Results.

In total, 145 of 1367 subjects were allocated to the DISH groups with a mean followup period of 5 years. Overall prevalence of a complete bone bridge increased in the pre-DISH group (11.3% to 31.0%) and in the definite DISH group (45.0% to 55.8%). The mean bridge score increased significantly in both the pre-DISH and definite DISH group (p < 0.001). The new bone gradually became more flowing and expanded circumferentially.

Conclusion.

Over the mean course of 5 years, the new bone developed from incomplete, pointy bone bridges to more flowing complete bridges. This suggests an ongoing and measurable bone-forming process that continues to progress, also in established cases of DISH.

Prevalence of Diffuse Idiopathic Skeletal Hyperostosis Diagnosed by Whole Spine Computed Tomography: A Preliminary Study

Background

Diffuse idiopathic skeletal hyperostosis (DISH) is characterized by ossification of the enthesis. The diagnosis has been mainly based on the chest or whole spine lateral plain film. Recently, chest or thoracolumbar computed tomography (CT) has been reported to be more reliable for the diagnosis of DISH. The purposes of this study were to investigate the prevalence and location of DISH and evaluate the prevalence of comorbidities, such as ossification of the posterior longitudinal ligament (OPLL) and ossification of the ligamentum flavum (OLF), using whole spine CT.

Methods

Whole spine CT scans of patients over 16 years of age who were examined at Cheju Halla General Hospital between February 2011 and December 2016 were reviewed for this study. The diagnosis of DISH was made according to the modified Resnick criteria. The prevalence of DISH in each age decade and its location were evaluated. Also, the prevalence of OPLL and OLF in DISH patients was investigated.

Results

The overall incidence of DISH was 24.4% (40 of 164 cases). There was no case of DISH in patients in their 40s and younger. The percentile incidences of DISH in patients in their fifth, sixth, seventh, eighth, and ninth decades were 20.0% (4 of 20 cases), 32.3% (10 of 31 cases), 40.0% (10 of 25 cases), 34.5% (10 of 29 cases), and 27.3% (6 of 22 cases), respectively. A strong positive correlation between the age decade and the incidence of DISH was noted (r = 0.853, p = 0.007). DISH patients had higher incidences of OLF (22.5%) and OPLL (37.5%). The most common location of DISH was the middle thoracic spine (90.0%) followed by the lower thoracic spine (87.5%). There was one case of DISH involving only the cervical spine.

Conclusions

The incidence of DISH diagnosed by CT was higher than we expected. Whole spine CT can be a valuable modality to evaluate the location of DISH in the cervical and lumbar spine and the comorbidity rates of OLF and OPLL.

Classification criteria for diffuse idiopathic skeletal hyperostosis: a lack of consensus

Objectives

DISH is a condition characterized by flowing ossifications of the spine with or without ossifications of entheses elsewhere in the body. Studies on the prevalence and pathogenesis of DISH use a variety of partly overlapping combinations of classification criteria, making meaningful comparisons across the literature difficult. The aim of this study was to systematically summarize the available criteria to support the development of a more uniform set of diagnostic/classification criteria.

Methods

A search was performed in Pubmed, Embase, Cochrane Library and Web of Science using the term DISH and its synonyms. Articles were included when two independent observers agreed that the articles proposed a new set of classification criteria for DISH. All retrieved articles were evaluated for methodological quality, and the presented criteria were extracted.

Results

A total of 24 articles met the inclusion criteria. In all articles, spinal hyperostosis was required for the diagnosis of DISH. Peripheral, extraspinal manifestations were included as a (co-)requirement for the diagnosis DISH in five articles. Most discrepancies revolved around the threshold for the number of vertebral bodies affected and to defining different developmental phases of DISH. More than half of the retrieved articles described a dichotomous set of criteria and did not consider the progressive character of DISH.

Conclusion

This systematic review summarizes the available different classification criteria for DISH, which highlights the lack of consensus on the diagnosis of (early) DISH. Consensus criteria, including consecutive phases of new bone formation that characterize DISH, can be developed based upon established diagnostic/classification criteria.

Diffuse idiopathic skeletal hyperostosis (DISH): where we are now and where to go next

Diffuse idiopathic skeletal hyperostosis (DISH) is a well-recognised entity characterised by calcifications and ossifications of the entheses affecting mainly the spine and peripheral sites. DISH is still insufficiently investigated and understood. The objective of this report is to highlight the present limitations of our understanding of the condition and suggest future research paths.

Magnetic resonance imaging in diffuse idiopathic skeletal hyperostosis: similarities to axial spondyloarthritis

Diffuse idiopathic skeletal hyperostosis (DISH) is a non-inflammatory condition that involves calcification and ossification of the spinal ligaments and entheses. While, characteristic magnetic resonance imaging (MRI) lesions of the spine in patients with axial spondyloarthritis, another enthesitis-related disease, have been described and defined, there is a paucity of information regarding the MRI findings in DISH. The aim of this study was to describe the MRI findings of patients with DISH. We collected computed tomography studies with findings characteristic of DISH and that also had corresponding and concurrent MRI studies of the spine. For each patient, sagittal T1-weighted and STIR MRI sequences were evaluated for anterior/posterior vertebral corners of bone marrow edema (BME) and fat deposition. In total, we assessed 156 vertebral units in 10 patients that had both radiographic evidence of DISH and available MRI studies of the spine. Lesions consistent with BME corners were detected in five patients, and in three of them, three separate sites were involved, a finding that is suggestive of axial spondyloarthritis (SpA) according to the ASAS/OMERACT consensus statement. Fat deposition corners were detected in eight patients and in seven of them, several sites were involved. Spinal MRI lesions that are characteristic of axial SpA were commonly observed in a cohort of patients with DISH. This bears relevance to cases with diagnostic uncertainty and may imply overlapping pathogenetic mechanisms for new bone formation in both SpA and DISH. Further study is indicated to better characterize the similarities and differences between the MRI lesions of DISH and SpA.

CT Abnormalities in the Sacroiliac Joints of Patients With Diffuse Idiopathic Skeletal Hyperostosis

OBJECTIVE

The purpose of this study is to characterize sacroiliac joints (SIJs) findings at CT of patients with diffuse idiopathic skeletal hyperostosis (DISH), a condition characterized (using the Resnick classification criteria) by ossification of at least four contiguous vertebrae in the thoracic spine and preserved disk space, but without radiographic evidence of intraarticular SIJ abnormalities.

MATERIALS AND METHODS

Pelvic CT examinations of 104 patients with DISH (fulfilling the Resnick criteria on spinal CT) and 106 age- and sex-matched control subjects whose entire spine lacked CT evidence of DISH (total, 149 men and 61 women; mean [± SD] age, 72.3 ± 8.7 years) were retrospectively evaluated for the presence of intra- and extraarticular bridging osteophytes, spurs, subchondral cystlike changes, erosions, and sclerosis of SIJs. Excluded were patients with known ankylosing spondylitis or inflammatory-related diseases. Data were analyzed using multivariate ANOVA to examine the degree of difference between patients with DISH and control subjects. Logistic regression analysis was used to generate odds ratios to examine their discriminatory ability. ROC analysis was then applied to examine the sensitivity and specificity of the results.

RESULTS

The frequency of anterior bridging, posterior bridging, entheseal bridging, and joint ankylosis was significantly higher among patients with DISH compared with control subjects (48% vs 9%, 20% vs 1%, 34% vs 4%, and 23% vs 0%, respectively; p < 0.001 for all comparisons).

CONCLUSION

Intraarticular ankylosis seen at CT, an entity not included in the Resnick classification criteria, is common among patients with DISH, which implies that the radiologic classification criteria for DISH need to be revised.

Prevalence of thoracic diffuse idiopathic skeletal hyperostosis (DISH) in Japanese: Results of chest CT-based cross-sectional study

BACKGROUND

The epidemiology and etiology of diffuse idiopathic skeletal hyperostosis (DISH) remain obscure. To date, to the best of our knowledge, there is no study that precisely evaluated the prevalence of thoracic DISH based on computed tomography (CT) data in large number of non-operated cohort with wide age distribution.

METHODS

The participants of this study were the consecutive patients who have undergone chest CT for the examination of pulmonary diseases in our institute. The patients with previous thoracic spine surgery and younger than 15 years old were excluded. Chest CT data were reconstructed in the condition suitable for bone evaluation by the software application. Definitive diagnosis of DISH was determined according to the criteria established by Resnick and Niwayama. Prevalence and distribution of thoracic DISH were reviewed and the data was statistically analyzed.

RESULTS

Total 3013 patients (1261 females and 1752 males) with the mean age of 65 years were recruited. The CT-based evidence of thoracic DISH was noted in 261 individuals (31 females and 230 males) (8.7%), and their mean age was 73 years. Statistical analyses revealed that thoracic DISH had a significant male preponderance. The mean age of thoracic DISH positive individuals was significantly higher than that of thoracic DISH negative individuals. There was significant difference of bone mass index (BMI) between thoracic DISH positive and negative individuals. Thoracic DISH was noted after the age of 40s with the highest distribution found at the age of 70s. No thoracic DISH localizes only higher thoracic region was found.

CONCLUSIONS

The CT-based prevalence of thoracic DISH in Japanese was 8.7%. Thoracic DISH has a significant predisposition to elderly male with high BMI.

Pelvic enthesopathy on CT is significantly more prevalent in patients with diffuse idiopathic skeletal hyperostosis (DISH) compared with matched control patients

The purpose of this study is to evaluate the prevalence of pelvic enthesopathy on computed tomography (CT) in patients with DISH compared to matched control group. Pelvic CT examinations of patients with DISH (Resnick criteria) were retrospectively evaluated for the presence of enthesophytes at four entheseal sites bilaterally: ischial tuberosity, pubis, greater trochanter, and anterior superior iliac spine (ASIS). This was compared with age- and gender-matched control group of consecutive patients with <2 flowing osteophytes on CT along the entire spine. Multivariate analysis of variance (ANOVA) was applied to examine the degree of difference between pelvic enthesopathy in DISH patients and controls and to estimate the potential predictive ability of the different findings. Logistic regression analysis was used to estimate the odds ratio of the studied findings. Pelvic CTs of 210 patients (149:61, M:F; average age, 72.3 years) were evaluated: DISH group, 104 patients (74:30, M:F); matched control group, 106 patients (75:31, M:F). Mean total and local enthesopathy scores were significantly higher in the DISH group compared with the control group (total 5.03:1.9; ASIS 1.58:0.55; pubis 0.94:0.36; ischial tuberosity 1.47:0.76; greater trochanter 1.04:0.24; p < 0.001). ASIS and greater trochanter enthesophytes were the most robust contributors that significantly distinguished between patients with DISH and those without DISH. Prominent enthesophytes were more common among DISH patients (DISH:controls, 52:13, p = 0.02). Prominent pelvic enthesophytes detected on CT have a strong discriminating power between DISH and non-DISH patients. Results imply that pelvic enthesopathy may be included in the radiographic criteria for DISH.