Comprehensive radiographic evaluation of diffuse idiopathic skeletal hyperostosis: development and interrater reliability of a scoring system

Risk factors for early-onset adjacent segment degeneration after one-segment posterior lumbar interbody fusion

Adjacent segment degeneration (ASD) is a major postoperative complication associated with posterior lumbar interbody fusion (PLIF). Early-onset ASD may differ pathologically from late-onset ASD. The aim of this study was to identify risk factors for early-onset ASD at the cranial segment occurring within 2 years after surgery. A retrospective study was performed for 170 patients with L4 degenerative spondylolisthesis who underwent one-segment PLIF. Of these patients, 20.6% had early-onset ASD at L3-4. In multivariate logistic regression analysis, preoperative larger % slip, vertebral bone marrow edema at the cranial segment on preoperative MRI (odds ratio 16.8), and surgical disc space distraction (cut-off 4.0 mm) were significant independent risk factors for early-onset ASD. Patients with preoperative imaging findings of bone marrow edema at the cranial segment had a 57.1% rate of early-onset ASD. A vacuum phenomenon and/or concomitant decompression at the cranial segment, the degree of surgical reduction of slippage, and lumbosacral spinal alignment were not risk factors for early-onset ASD. The need for fusion surgery requires careful consideration if vertebral bone marrow edema at the cranial segment adjacent to the fusion segment is detected on preoperative MRI, due to the negative impact of this edema on the incidence of early-onset ASD.

Utility of MRI-based vertebral bone quality scores and CT-based Hounsfield unit values in vertebral bone mineral density assessment for patients with diffuse idiopathic skeletal hyperostosis

This study investigated bone mineral density assessment for patients with DISH. DXA-based T-scores overestimated bone quality, while MRI-based VBQ scores and CT-based HU values provided accurate assessments, particularly for advanced degenerative cases. This enhances accurate evaluation of BMD, crucial for clinical decision-making.

PURPOSE

To investigate the diagnostic effectiveness of DXA, MRI, and CT in assessing bone mineral density (BMD) for diffuse idiopathic skeletal hyperostosis (DISH) patients.

METHODS

Retrospective analysis of 105 DISH patients and 116 age-matched controls with lumbar spinal stenosis was conducted. BMD was evaluated using DXA-based T-scores, MRI-based vertebral bone quality (VBQ) scores, and CT-based Hounsfield unit (HU) values. Patients were categorized into three BMD subgroups. Lumbar osteophyte categories were determined by Mata score. Demographics, clinical data, T-scores, VBQ scores, and HU values were collected. Receiver operating characteristic (ROC) analysis identified VBQ and HU thresholds for diagnosing normal BMD using DXA in controls. Correlations between VBQ, HU, and lumbar T-score were analyzed.

RESULTS

Age, gender, and BMI showed no significant differences between DISH and control groups. DISH patients had higher T-score (L1-4), the lowest T-score, and Mata scores. VBQ and HU did not significantly differ between groups. In controls, VBQ and HU effectively diagnosed normal BMD (AUC = 0.857 and 0.910, respectively) with cutoffs of 3.0 for VBQ and 104.3 for HU. DISH had higher normal BMD prevalence using T-scores (69.5% vs. 58.6%, P < 0.05), but no significant differences using VBQ (57.1% vs. 56.2%, P > 0.05) and HU (58.1% vs. 57.8%, P > 0.05). Correlations revealed moderate correlations between HU and T-scores (L1-4) in DISH (r = 0.642, P < 0.001) and strong in controls (r = 0.846, P < 0.001). Moderate negative correlations were observed between VBQ and T-scores (L1-4) in DISH (r =  - 0.450, P < 0.001) and strong in controls (r =  - 0.813, P < 0.001).

CONCLUSION

DXA-based T-scores may overestimate BMD in DISH. VBQ scores and HU values could effectively complement BMD assessment, particularly in DISH patients or those with advanced lumbar degeneration.

How Sagittal Spinal Parameters Predict Anterolateral Spinal Ossification Severity: A Study Based on CT Classification

STUDY DESIGN

Retrospective observational study.

OBJECTIVE

The purpose of this study was to establish a CT classification system of anterolateral spinal ossification and analyze the effects of sagittal spinal parameters on ossification.

SUMMARY OF BACKGROUND DATA

Patients with diffuse idiopathic skeletal hyperostosis often present with anterolateral ossification of the spine. Few reports consider anterolateral spinal ossification at each spinal level or explore the influence of sagittal alignment.

MATERIALS AND METHOD

One hundred and twenty patients (79 males and 41 females) over 60 years old who underwent whole spinal CT scans from October 2018 to November 2021 were analyzed. Volume rendering technique images were used to assess the degree of anterolateral spinal ossification in each intervertebral space, and a classification system was established. Sagittal parameters, such as thoracic kyphosis, lumbar lordosis (LL), cervical lordosis, sacral slope, and thoracolumbar junction angle of the patients were measured. Multifactor stepwise linear regression analysis and ordered logistic regression analysis were used to study the effects of the sagittal parameters on ossification grades.

RESULTS

The median age of the study population was 67 years (63-72 IQR). The new classification system classifies the severity of anterolateral spinal ossification in each intervertebral space into grades 0 to 3 with an intra-observer intraclass correlation coefficient value of 0.909 and inter-observer intraclass correlation coefficient value of 0.900. Multivariate stepwise linear regression analysis showed that age (OR=1.30, P <0.001), weight (OR=1.23, P =0.013), and cervical lordosis (OR=1.19, P <0.001) were significantly correlated with total ossification grade. Multifactor ordered logistic regression analysis showed that there was a statistically significant correlation between cervical lordosis and the ossification grades of each intervertebral space of T1~T4 ( P ≤0.005), between thoracic kyphosis and each intervertebral space in T4~T12 ( P ≤0.019), and between thoracolumbar junction angle and each intervertebral space in T10~L3 ( P ≤0.025). LL was significantly and positively correlated with the ossification grades of each intervertebral space in T7~T11 ( P ≤0.041). LL and sacral slope were significantly negatively correlated with the ossification grades of each intervertebral space in L3~S1 ( P ≤0.047).

CONCLUSION

Our new classification scheme demonstrated good accuracy and reliability for the evaluation of the severity of anterolateral spinal ossification. The effect of sagittal parameters on anterolateral spinal ossification was position-specific. The greater the kyphosis or the smaller the lordosis of a spinal region, the more severe the degree of ossification in the corresponding region.

LEVEL OF EVIDENCE

3.

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.

Risk of further surgery after decompression in patients with diffuse idiopathic skeletal hyperostosis extending to the lumbar segments: focus on the number of residual lumbar/lumbosacral and sacroiliac mobile segments

PURPOSE

Patients with diffuse idiopathic skeletal hyperostosis (DISH) that extends to the lumbar segments (L-DISH) have a high risk of further surgery after lumbar decompression. However, few studies have focused on the ankylosis status of the residual caudal segments, including the sacroiliac joint (SIJ). We hypothesized that patients with more ankylosed segments beside the operated level, including the SIJ, would be at a higher risk of further surgery.

METHODS

A total of 79 patients with L-DISH who underwent decompression surgery for lumbar stenosis at a single academic institution between 2007 and 2021 were enrolled. The baseline demographics and radiological findings by CT imaging focusing on the ankylosing condition of the residual lumbar segments and SIJ were collected. Cox proportional hazard analysis was conducted to investigate the risk factors for further surgery after lumbar decompression.

RESULTS

The rate of further surgery was 37.9% during an average of 48.8 months of follow-up. Cox proportional hazard analysis demonstrated that the presence of fewer than three segments of non-operated mobile caudal segments was an independent predictor for further surgery (including both the same and adjacent levels) after lumbar decompression (adjusted hazard ratio 2.53, 95%CI [1.12-5.70]).

CONCLUSIONS

L-DISH patients with fewer than three mobile caudal segments besides index decompression levels are at a high risk of further surgery. Ankylosis status of the residual lumbar segments and SIJ should be thoroughly evaluated using CT during preoperative planning.

A radiological study of the natural history of diffuse idiopathic skeletal hyperostosis (DISH): a story of incomplete fusion

Introduction: DISH is an ankylosing disease, when fractured can be challenging to manage. A retrospective radiological study was conducted to evaluate the natural history and radiological characteristics of DISH on Computed tomography (CT).Methods: Paired CT scans with DISH that are separated at least two years apart were used to perform the following radiological measurements: Degree of disc space fusion, Osteophyte and vertebral body linear attenuation coefficients (LAC), and Osteophyte axial area size and location.Results: 164 patients were analysed with a mean duration of 4.49 years between scans. 38.14% (442/1159) of disc spaces had at least partial calcification. Most osteophytes were right sided before becoming more circumferential over time. The average fusion score was 54.17. Most of the changes in fusion occurred in the upper and lower thoracic regions. The thoracic region when compared to the lumbar region had a greater proportion of its disc spaced being fully fused. Disc level osteophyte areas were larger than Body level osteophytes. Disc osteophytes size growth rate drops over time from 10.89mm²/year in Stage 1 to 3.56mm²/year in Stage 3. Stage 3 disc spaces (-11.01HU/year) was also found to have had a reduction in their LAC over time when compared to Stage 1 disc spaces (17.04HU/year). This change in osteophyte LAC was not mirrored in the change in vertebral body LAC. We predict that the age of onset and complete thoracolumbar ankylosis of DISH to be 17.96 years and 100.59 years, respectively.Conclusion: DISH ankylosis of the spine a slow process that starts in the mid to lower thoracic region before extending cranially and caudally. After the bridging osteophyte has fully formed, remodelling of the osteophyte occurs.

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.

Prognostic Factors and Optimal Surgical Management for Lumbar Spinal Canal Stenosis in Patients with Diffuse Idiopathic Skeletal Hyperostosis

Lumbar spinal canal stenosis (LSS) and diffuse idiopathic skeletal hyperostosis (DISH) tend to develop in the elderly, resulting in an increased need for lumbar surgery. However, DISH may be a risk factor for poor clinical outcomes following lumbar decompression surgery, especially in patients with DISH extending to the lumbar segment (L-DISH). This study aimed to identify the prognostic factors of LSS with L-DISH and propose an optimal surgical management approach to improve clinical outcomes. Of 934 patients who underwent lumbar decompression surgery, 145 patients (15.5%) had L-DISH. In multivariate linear regression analysis of the JOA score improvement rate, the presence of vacuum phenomenon at affected segments (estimate: −15.14) and distance between the caudal end of L-DISH and decompressed/fused segments (estimate: 7.05) were independent prognostic factors. In logistic regression analysis of the surgical procedure with JOA improvement rate > 25% in L-DISH patients with both negative prognostic factors, the odds ratios of split laminotomy and short-segment fusion were 0.64 and 0.21, respectively, with conventional laminotomy as the reference. Therefore, to achieve better clinical outcomes in cases with decompression at the caudal end of L-DISH, decompression surgery without fusion sparing the osteoligamentous structures at midline should be considered as the standard surgery.

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.

Can Diffuse Idiopathic Skeletal Hyperostosis Be Diagnosed by Plain Lumbar Spine X-Ray Findings Alone?

STUDY DESIGN

Retrospective case-control study.

OBJECTIVES

To determine whether diffuse idiopathic skeletal hyperostosis (DISH) can be diagnosed based on anterior longitudinal ligamental ossification in the lumbar spine using plain lumbar spine X-ray images.

METHODS

This study included 100 patients (59 men and 41 women; mean age, 64.8 ± 13.8 years; range, 27-89 years) who underwent computed tomography (CT) of the chest to the pelvis in our hospital and plain lumbar spine radiography within 6 months before and after CT scanning. DISH was diagnosed based on the thoracolumbar spine CT findings using Resnick's diagnostic criteria. The patients were grouped according to DISH diagnosis into the DISH (+) and DISH (-) groups. On the frontal and lateral lumbar spine X-ray images, each spinal level from Th11/12 to L5/S was scored based on the Mata scoring system. The distribution of the Mata scores was compared between the 2 groups.

RESULTS

Forty (40%) patients were diagnosed with DISH based on the CT findings. A cutoff value ≥8 provided a sensitivity of 75% and specificity of 100% for diagnosing DISH, thus, indicating the validity of the cutoff value. In the DISH (-) group, no patient had ≥3 consecutive spinal levels with a Mata score ≥2, suggesting that DISH can be diagnosed on the basis of at least 3 consecutive spinal levels with a Mata score ≥2.

CONCLUSION

On lumbar spine X-ray images of the T11/12 to L5/S levels, a Mata score ≥2 for at least 3 consecutive levels or a total score ≥8 strongly indicates the presence of DISH.

Risk Factors for Reoperation at Same Level after Decompression Surgery for Lumbar Spinal Stenosis in Patients with Diffuse Idiopathic Skeletal Hyperostosis Extended to the Lumbar Segments

Introduction

Diffuse idiopathic skeletal hyperostosis (DISH) extended to the lumbar segments (L-DISH) reportedly has adverse effects on the surgical outcomes of lumbar spinal stenosis (LSS). However, the risk factors in patients with L-DISH have not been clarified. The purpose of this study was to investigate the long-term risk factors for reoperation at the same level after decompression surgery alone for LSS in patients with L-DISH in a retrospective cohort study.

Methods

A postoperative postal survey was sent to 1,150 consecutive patients who underwent decompression surgery alone for LSS from 2002 to 2010. Among all respondents, patients who exhibited L-DISH by preoperative total spine X-ray were included in this study. We investigated risk factors for reoperation at the same level as the initial surgery among various demographic and radiological parameters, including the lumbar ossification condition and computed tomography (CT) or magnetic resonance imaging findings.

Results

A total of 57 patients were analyzed. Reoperations at the same level as that of the index surgery were performed in 10 patients (17.5%) and at 11 levels within a mean of 9.2 years. Cox proportional hazard regression analysis indicated that the independent risk factors for reoperation were a sagittal rotation angle ≥10° (adjusted hazard ratio: 5.17) and facet opening on CT (adjusted hazard ratio: 4.82). Neither sagittal translation nor the ossification condition in the lumbar segments affected reoperations.

Conclusions

A sagittal rotation angle ≥10° and facet opening on preoperative CT were risk factors for reoperation at the same level as that of the index surgery in patients with L-DISH. The surgical strategy should be carefully considered in those patients.

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

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

Negative impact of short-level posterior lumbar interbody fusion in patients with diffuse idiopathic skeletal hyperostosis extending to the lumbar segment

OBJECTIVE

The development of diffuse idiopathic skeletal hyperostosis (DISH) often requires further surgery after posterior decompression without fusion because of postoperative intervertebral instability. However, there is no information on whether fusion surgery is recommended for these patients as the standard surgery. The aim of this study was to review the clinical and imaging findings in lumbar spinal canal stenosis (LSS) patients with DISH affecting the lumbar segment (L-DISH) and to assess the indication for fusion surgery in patients with DISH.

METHODS

A total of 237 patients with LSS underwent 1- or 2-level posterior lumbar interbody fusion (PLIF) at the authors' hospital and had a minimum follow-up period of 2 years. Patients with L-DISH were classified as such (n = 27, 11.4%), whereas those without were classified as controls (non-L-DISH; n = 210, 88.6%). The success rates of short-level PLIF were compared in patients with and those without L-DISH. The rates of adjacent segment disease (ASD), pseudarthrosis, postoperative symptoms, and revision surgery were examined in the two groups.

RESULTS

L-DISH from L2 to L4 correlated significantly with early-onset ASD, pseudarthrosis, and the appearance of postsurgical symptoms, especially at a lower segment and one distance from the segment adjacent to L-DISH, which were associated with the worst clinical outcome. Significantly higher percentages of L-DISH patients developed ASD and pseudarthrosis than those in the non-L-DISH group (40.7% vs 4.8% and 29.6% vs 2.4%, respectively). Of those patients with ASD and/or pseudarthrosis, 69.2% were symptomatic and 11.1% underwent revision surgery.

CONCLUSIONS

The results highlighted the negative impact of short-level PLIF surgery for patients with L-DISH. Increased mechanical stress below the fused segment was considered the reason for the poor clinical outcome.

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

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

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.

Pathomechanism and prevention of further surgery after posterior decompression for lumbar spinal canal stenosis in patients with diffuse idiopathic skeletal hyperostosis

BACKGROUND CONTEXT

Diffuse idiopathic skeletal hyperostosis (DISH) is a risk factor for further surgery after posterior decompression without fusion for patients with lumbar spinal canal stenosis (LSS). However, a strategy to prevent revision surgery has not been described.

PURPOSE

The aim of this study was to review clinical and imaging findings in LSS patients with DISH extending to the lumbar segment and to propose countermeasures for prevention of revision surgery.

STUDY DESIGN

A retrospective study.

PATIENTS SAMPLE

A total of 613 consecutive patients with LSS underwent posterior decompression without fusion at our hospital and had a minimum follow-up period of 2 years. We defined patients with DISH bridging to the lumbar segment as L-DISH cases (group D, n=111), and those without as non-L-DISH cases (group N, n=502).

OUTCOME MEASURE

Demographic data including the rate of revision surgery, neurological examination using Japanese Orthopaedic Association score, radiological studies comprised plain lumbar radiography, CT, and high-resolution MRI were assessed.

METHODS

Clinical features and imaging findings were compared in patients with and without L-DISH. Revision surgery and surgical procedures (conventional laminotomy or lumbar spinous process-splitting [split] laminotomy) were examined in the two groups. No funding was received for this study.

RESULTS

L-DISH from L2 to L4 was a risk factor for disc degeneration such as a vacuum phenomenon and for further surgical treatment. The rate of revision surgery was higher in group D than in group N (9.0% vs. 4.0%, p=.026). There was no significant difference in this rate for patients in groups D and N who underwent conventional laminotomy; however, for those who underwent split laminotomy, the rate was significantly higher in group D (16.7% vs. 2.1%, p=.0006). Furthermore, the rate of revision surgery after split laminotomy at a lower segment adjacent to L-DISH was significantly higher than that after conventional laminotomy (37.5% vs. 7.7%, p=.037).

CONCLUSIONS

A negative impact of lumbar spinous process-splitting laminotomy was found, especially with decompression at a lower segment adjacent to L-DISH. In such cases, surgery sparing the osteoligamentous structures at midline, including the spinous process and supra- and interspinous ligaments, should be selected.

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.

Obesity and calcification of the ligaments of the spine: a comprehensive CT analysis of the entire spine in a random trauma population

BACKGROUND CONTEXT

Obesity, which is currently surging to epidemic levels within the United States, has been linked to hyperostotic conditions like diffuse idiopathic skeletal hyperostosis (DISH) and ossification of the posterior longitudinal ligament (OPLL). Excess adipose tissue and insulin-resistance may cause a systemic increase in serum levels of proinflammatory cytokines and these signals can affect bone metabolism. Spinal ligaments and discs may have receptors for these signaling molecules. Anecdotal observations at this institution suggested that there is a clinically important subset of younger patients with obesity and multilevel stenosis in the presence of unusual calcification of the spinal ligaments that is distinct from DISH.

PURPOSE

To determine if there is an association between truncal obesity and calcifications of the spine in nonelderly adults.

STUDY DESIGN/SETTING

This is a retrospective analysis of 214 sequential trauma patients between the ages of 29 and 50. Patients' age, sex, truncal obesity, history of hypertension, and diabetes were assessed for association with ligamentous calcification of the spine.

PATIENT SAMPLE

Sequential trauma patients were chosen from our institution's trauma database between 2006 and 2007.

METHODS

Full spine computed tomography (CT) imaging was examined for bone formation in the region of the anterior longitudinal ligament (ALL) and annulus, posterior longitudinal ligament (PLL) and annulus, and the ligamentum flavum (LF). Visceral and subcutaneous abdominal fat were also evaluated. The authors report no study funding sources or conflicts of interest.

OUTCOME MEASURES

Calcification of the ALL, PLL, and LF were assigned a score at each level and then combined for a total calcification score (TCS) for the entire spine. Obesity was estimated using a truncal body mass index (TBMI) by using a previously validated CT derived truncal total adiposity volume (TAV).

RESULTS

ALL calcification was associated with age, male gender, hypertension, and increased adiposity. PLL calcification was significantly associated with age and hypertension. LF calcification was only associated with increased obesity.

CONCLUSIONS

In our analysis of nonelderly patients, LF calcification was independently associated with truncal obesity. This implies obesity plays a greater role in calcification than could be accounted for by simply age-related degeneration or gender.

Conservative treatment for stable low-energy thoracolumbar vertebral fractures in nonfused segments among elderly patients with diffuse idiopathic skeletal hyperostosis: A matched case-control study

Diffuse idiopathic skeletal hyperostosis (DISH) is the spontaneous osseous fusion of the spine with anterior bridging osteophytes. It is well-known that conservative treatment for vertebral fractures of fused segment among DISH spines is associated with worse clinical outcomes. However, the prognosis of conservatively treated stable vertebral fractures in neighboring nonfused segments among DISH spines is still unknown. The purpose of this study was to analyze the results of conservative treatment of stable low-energy thoracolumbar (TL) vertebral fracture in nonfused segments among patients with DISH lesions.A total of 390 consecutive patients who visited an emergency department by ambulance with spinal trauma between 2013 and 2017 were retrospectively reviewed. The diagnosis of DISH was determined based on fused spinal segments with bridging osteophytes in at least 3 adjacent vertebrae. For each case of stable TL vertebral fractures in nonfused segments of the DISH spine, we identified 2 age-, sex-, and fracture lesion-matched non-DISH controls who underwent conservative treatment for low-energy TL vertebral fractures during the same period.Of the 33 identified cases of TL fractures with DISH, 14 met our inclusion criteria. The bony union rates of the DISH group and control group were 57% and 75% at the 3-month follow-up examination (P = .38) and 69% and 100% at the 6-month follow-up examination (P = .02), respectively. Among the 13 patients with fractures below the TL junction, fused segments were not diagnosable based on the initial standard radiographs of the lumbar spine for 61.5% of patients.Although this study design was exploratory and the sample size was small, our results suggest that with conservative treatment, stable fractures in nonfused segments in the DISH spine might have a worse prognosis than ordinary osteoporotic vertebral fractures. The diagnosis of coexisting DISH lesions can be missed when only radiographs of the lumbar spine are used to determine the diagnosis.

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.

Selective mortality in middle-aged American women with Diffuse Idiopathic Skeletal Hyperostosis (DISH)

OBJECTIVE

A mortality sample of white American male and female skeletons was examined to illustrate a simple means of identifying skeletal conditions associated with an increased risk of dying relatively early in adulthood and to determine if males and females with Diffuse Idiopathic Skeletal Hyperostosis (DISH) displayed the same general age-specific pattern of mortality.

METHODS

Age-specific probability distributions for DISH were generated from 416 white Americans who died from the 1980s to the present, and whose remains were donated to the University of Tennessee Forensic Anthropology Center. The age-specific frequency of DISH is analyzed using an empirical smoothing algorithm. Doing so allows for the identification of deviations (i.e., local maxima) from monotonically increasing age-specific probabilities.

RESULTS

In females (N = 199), there is a peak in the frequency of individuals with DISH around 60 years of age where 37.0% of the individuals have DISH. It is matched only by the frequency (38.7%) in the oldest females, those over 85 years old. In contrast, DISH frequencies for males (N = 217) increase monotonically with advancing age, reaching 62.5% in the ≥86 years age group. There was an association between DISH and high body weight in women, particularly those who died before they reached the age of 75.

CONCLUSIONS

Early-onset DISH in white American women is associated with an increased risk of dying indicated by a local maximum in the probability curve. Should this finding be replicated in additional mortality samples and the reason DISH is associated with early death is established, beyond being heavy, this radiologically visible ossification of the spine could be a potential component of health-monitoring programs for middle-aged women.

Prevalence of diffuse idiopathic skeletal hyperostosis (DISH) assessed with whole-spine computed tomography in 1479 subjects

Background

Computed tomography (CT) analyses have reported that the prevalence of diffuse idiopathic skeletal hyperostosis (DISH) in Japan is 8.7–27.1%. However, these data were obtained using chest-abdominal CT, and no evaluations of sagittal, coronal, and axial images using whole-spine CT have been reported. The aim of this study was to investigate the prevalence and characteristic of DISH by whole spinal CT.

Methods

Participants were patients who had experienced trauma who had undergone whole-spine CT scanning based on the initial clinical practice guidelines for trauma in our institute from April 2015 to February 2018. The subjects were > 20 years old and 1479 were included in the analysis. The presence and distribution of DISH and clinical parameters such as age and sex were reviewed retrospectively according to the location of DISH.

Results

The overall prevalence of DISH was 19.5% (n = 289). Subjects with DISH were older than those without. DISH was located in the thoracic spine in 65.1% and thoracolumbar spine in 24.2% of patients. More than 80% of ligamentous ossifications associated with DISH occurred at T8 (n = 255, 88%), T9 (n = 262, 91%), and T10 (n = 247, 85%). Most of the ossification occurred to the right anterior of the vertebral body, and there were few ossifications in the areas in contact with the artery and vein.

Conclusions

The prevalence of DISH based on whole-spine CT was 19.5%. Ossification was noted more often at T8, T9, and T10, and to the right anterior of the vertebral body. It is for the first time report that we have studied the location of ossification in detail using the axial images of whole spine CT. We hope this study will enhance the understanding of the characteristics of DISH.

Electronic supplementary material

The online version of this article (10.1186/s12891-018-2108-5) contains supplementary material, which is available to authorized users.

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.

Drug therapy targeting pyrophosphate slows the ossification of spinal ligaments in twy mice

The lack of an effective drug therapy against ossification of spinal ligament (OSL) warrants investigation into the therapeutic target of this disease. An endogenous inhibitor of biomineralization, pyrophosphate (PPi) is a potential therapy for ectopic ossification; however, exogenous PPi is rapidly hydrolyzed by tissue non-specific alkaline phosphatase (TNAP) present in body fluids. In this study, we examined whether a drug therapy targeting PPi is efficacious for the treatment of OSL using the Enpp1^ttw/ttw (twy) mouse model. Twenty male twy mice were randomized into four groups: (i) vehicle (Control); (ii) alkaline phosphatase inhibitor levamisole (5 mg/kg/day sc continuously); (iii) levamisole + exogenous PPi (160 µmol/kg/day sc continuously); and (iv) nuclear retinoic acid receptor-γ (RARγ) agonist (6 µg/kg sc daily). The RARγ agonist, which is a proven inhibitor of ectopic endochondral ossification, was used as a positive control. Treatments commenced when the mice were 5 weeks of age and continued for 4 weeks. Longitudinal micro-computed tomography and postmortem histological analysis were performed. Administration of levamisole alone and in combination with PPi increased serum PPi concentration by 17% and 52%, respectively, compared to that in vehicle-treated mice. The development of OSL in twy mice was suppressed by levamisole + PPi and RARγ agonist treatments, but not by levamisole alone. The levamisole + PPi therapy did not cause osteoporosis, whereas RARγ agonist-treated mice developed osteoporosis. Treatment of twy mice with levamisole in combination with exogenous PPi increased serum PPi level, which slowed the progression of OSL without producing adverse effect on bone. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:1256-1261, 2018.

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.

Prevalence of Diffuse Idiopathic Skeletal Hyperostosis in Patients with Spinal Disorders

Study Design

Retrospective cohort study.

Purpose

The purpose of this study was to evaluate the prevalence of diffuse idiopathic skeletal hyperostosis (DISH) in patients with spinal diseases determined by roentgen images of the whole spine.

Overview of Literature

Although several studies have investigated the prevalence of DISH in healthy subjects, no detailed data have been reported on the prevalence of DISH in patients with degenerative spinal disorders.

Methods

Standing whole-spine roentgen images of 345 consecutive patients who underwent surgery in our hospital were obtained. Patients aged <18 years or with congenital spinal disease, metastatic spinal tumors, or inflammatory spinal disease were excluded. In total, 281 patients were eligible for inclusion. The presence of DISH was assessed according to Resnick's criteria and Mata's scoring system. The prevalence, location, and numbers of fused vertebral bodies of DISH were recorded.

Results

DISH was present in 25.6% of patients (72/281). The prevalence of DISH in the 41–49, 50–59, 60–69, 70–79, and ≥80 year age groups was 8.3% (2/24), 9.8% (5/51), 16.0% (12/75), 49.5% (48/97), and 33.3% (4/12), respectively; the prevalence increased with age. The average number of fused vertebral bodies was 7.5. More than 80% of DISH was located from T7 to T11, and more than 95% of DISH was located at T9/10. Patients with DISH were significantly older (71.1 years vs. 60.9 years, p<0.05), and men were more likely to have DISH than women (p<0.05).

Conclusions

In patients with degenerative spinal diseases with DISH, fused vertebrae were found most frequently in the lower thoracic spine, and their prevalence increased with age. DISH may be an age-related skeletal disorder with a higher overall prevalence in patients with spinal disorders than that in healthy subjects.

Diffuse idiopathic skeletal hyperostosis (DISH) - A common but less known cause of back pain

Diffuse idiopathic skeletal hyperostosis (DISH) is a systemic non-inflammatory disease of an unknown aetiology. It is characterized by ossification of the enthesis and may significantly affect the quality of life of the affected individuals. Despite the fact that this disease was first described more than 60 years ago and is a relatively common condition in the society, its awareness among clinician is still limited. An awareness of this entity and its mimicking conditions is essential so as to reach to an early diagnosis and avoid unnecessary investigations and treatment.

Cervical Myeloradiculopathy due to Ossification of the Posterior Longitudinal Ligament with versus without Diffuse Idiopathic Spinal Hyperostosis

Study Design Retrospective study. Objectives Assess demographics, ossification characteristics, surgical outcomes, and complications in patients with both diffuse idiopathic spinal hyperostosis (DISH) and ossification of the posterior longitudinal ligament (OPLL) compared with patients who only have OPLL. Methods Clinical charts and radiographs of all patients treated surgically from February 2004 to July 2012 for cervical myeloradiculopathy due to DISH with OPLL or OPLL alone were reviewed retrospectively. All patients were observed for a minimum of 1 year. Pre- and postoperative Nurick grades were assessed for all patients. Results Forty-nine patients underwent surgical treatment for cervical myeloradiculopathy due to OPLL, and 8 also had DISH (average 58.9 years, range 37 to 70). The DISH with OPLL group had a significantly higher proportion of subjects with diabetes mellitus (50 versus 9.8% in the OPLL-only group). Everyone in the DISH with OPLL group had continuous or mixed-type OPLL, whereas 78% of patients in the OPLL-only group had primarily segmental type. Operative treatments for patients in the DISH with OPLL group included laminoplasty, anterior decompression and fusion, and posterior laminectomy with fusion. By Nurick grade, 5 patients improved and 3 showed no change. Conclusion Patients with both DISH and OPLL had a higher prevalence of diabetes mellitus and either continuous or mixed-type OPLL classifications. Surgical outcomes were mostly satisfactory; there was no aggravation of symptoms after surgery during the follow up period.

Diagnosis of diffuse idiopathic skeletal hyperostosis with chest computed tomography: inter-observer agreement

Objective

To evaluate and improve the interobserver agreement for the CT-based diagnosis of diffuse idiopathic skeletal hyperostosis (DISH).

Methods

Six hundred participants of the CT arm of a lung cancer screening trial were randomly divided into two groups. The first 300 CTs were scored by five observers for the presence of DISH based on the original Resnick criteria for radiographs. After analysis of the data a consensus meeting was organised and the criteria were slightly modified regarding the definition of ‘contiguous’, the definition of ‘flowing ossifications’ and the viewing plane and window level. Subsequently, the second set of 300 CTs was scored by the same observers. κ ≥ 0.61 was considered good agreement.

Results

The 600 male participants were on average 63.5 (SD 5.3) years old and had smoked on average 38.0 pack-years. In the first round κ values ranged from 0.32 to 0.74 and 7 out of 10 values were below 0.61. After the consensus meeting the interobserver agreement ranged from 0.51 to 0.86 and 3 out of 10 values were below 0.61. The agreement improved significantly.

Conclusions

This is the first study that reports interobserver agreement for the diagnosis of DISH on chest CT, showing mostly good agreement for modified Resnick criteria.

Key Points

• DISH is diagnosed on fluoroscopic and radiographic examinations using Resnick criteria

• Evaluation of DISH on chest CT was modestly reproducible with the Resnick criteria

• A consensus meeting and Resnick criteria modification improved inter-rater reliability for DISH

• Reproducible CT criteria for DISH aids research into this poorly understood entity

Teriparatide Improves Trabecular Osteoporosis but Simultaneously Promotes Ankylosis of the Spine in the Twy Mouse Model for Diffuse Idiopathic Skeletal Hyperostosis

Diffuse idiopathic skeletal hyperostosis (DISH) is a common skeletal disorder in the elderly, which can develop into periosteal hyperostosis and paradoxically into immobilization-associated trabecular osteoporosis. The bone anabolic agent, teriparatide (TPD), seems to be a rational treatment for the immobilization-associated osteoporosis. However, it can lead to development of hyperostosis lesions in DISH patients. Here, we demonstrate TPD effectively treats trabecular osteoporosis while simultaneously promoting ankylosis of the spine in DISH model tiptoe-walking Yoshimura (twy) mice, compared with the ICR mice. Eighteen male twy mice were divided into three groups, and ICR mice were used as a normal control. Subcutaneous injections of TPD or phosphate-buffered saline (PBS) were performed according to three dosing regimens; 40 µg/kg once daily (TPD × 1 group), 40 µg/kg three times daily (TPD × 3 group), and PBS (control; Ctl group). Treatment was commenced at the age of 7 weeks and continued for 5 weeks. Micro-computed tomography (µCT) and histological analysis were performed. Longitudinal µCT study revealed that trabecular bone volume in both the vertebral body and distal femur decreased with time in the Ctl group, but increased dramatically in the TPD × 3 group. The twy mice developed ankylosis of the spine, the progression of which was accelerated with TPD therapy. We also confirmed that TPD therapy promoted ossification of spinal ligaments. Histomorphometrical study revealed that TPD treatment increased bone formation at the vertebrae enthesis region and in the trabecular bone. TPD therapy effectively treats trabecular osteoporosis, but potentially promotes ankylosis of the spine in patients with DISH.

Diffuse idiopathic skeletal hyperostosis (DISH) of the elbow: a controlled radiological study

BACKGROUND

Extraspinal manifestations of diffuse idiopathic skeletal hyperostosis (DISH) have been described previously. We aimed to assess the prevalence of elbow hyperostotic spurs, to search for sites discriminating for elbow DISH and to analyze the effect of physical activities, handedness and sex.

METHODS

Out of 284 patients hospitalized for extraskeletal disorders, 85 patients (33 with and 52 without thoracospinal DISH) agreed to bilateral elbow X-rays in two projections. Clinical information was collected by a standardized questionnaire and X-rays were graded blindly.

RESULTS

A total of 400 hyperostotic spurs (210 unilateral, 95 bilateral) were present at 11 predefined sites. The most frequent sites affected were the olecranon (20.8%), lateral epicondyle (17.8%) and medial epicondyle (15.5%). In carriers of thoracospinal DISH significantly more hyperostotic spurs were present at the lateral and medial epicondyle compared to non-DISH carriers (OR 4.01 [95% CI 1.35-12.34] and 2.88 [1.03-8.24], respectively). The olecranon, lateral and medial epicondyle contributed significantly to the classification of elbow DISH (OR 22.2 [4.1-144.7], 9.6 [1.9-61.2] and 10.1 [2.2-52.1], respectively). The prevalence of elbow hyperostotic spurs was higher in 45 patients with a history of heavy physical activities (24.4% versus 18.0%, OR 1.48 [1.17-1.86]), at the right elbow (24.2% versus 18.6%, OR 1.39 [1.11-1.75]) and in 62 males (22.8% versus 17.6%, OR 1.38 [1.06-1.81]).

CONCLUSIONS

Hyperostotic spurs at the olecranon, lateral and medial epicondyle had the highest prevalence and disclosed the most pronounced discrimination for elbow DISH. Mechanical factors such as physical activities and handedness, and sex influenced the formation of these spurs.

Prevalence of diffuse idiopathic skeletal hyperostosis (DISH) of the whole spine and its association with lumbar spondylosis and knee osteoarthritis: the ROAD study

We aimed to assess the prevalence of diffuse idiopathic skeletal hyperostosis (DISH) and its association with lumbar spondylosis (LS) and knee osteoarthritis (KOA) using a population-based cohort study entitled Research on Osteoarthritis/osteoporosis Against Disability (ROAD). In the baseline ROAD study, which was performed between 2005 and 2007, 1,690 participants in mountainous and coastal areas underwent anthropometric measurements and radiographic examinations of the whole spine (cervical, thoracic, and lumbar) and both knees. They also completed an interviewer-administered questionnaire. Presence of DISH was diagnosed according to Resnick criteria, and LS and KOA were defined as Kellgren-Lawrence (KL) grade ≥3. Among the 1,690 participants, whole-spine radiographs of 1,647 individuals (97.5%; 573 men, 1,074 women; mean age, 65.3 years) were evaluated. Prevalence of DISH was 10.8% (men 22.0%, women 4.8%), and was significantly higher in older participants (presence of DISH 72.3 years, absence of DISH 64.4 years) and mainly distributed at the thoracic spine (88.7%). Logistic regression analysis revealed that presence of DISH was significantly associated with older age [+1 year, odds ratio (OR): 1.06, 95% confidence interval (CI): 1.03-1.14], male sex (OR: 5.55, 95% CI: 3.57-8.63), higher body mass index (+1 kg/m(2), OR: 1.08, 95% CI: 1.02-1.14), presence of LS (KL2 vs KL0: 1, OR: 5.50, 95% CI: 2.81-10.8) (KL ≥3 vs KL0: 1, OR: 4.09, 95% CI: 2.08-8.03), and presence of KOA (KL ≥3 vs KL0: 1, OR: 1.89, 95% CI: 1.14-3.10) after adjusting for smoking, alcohol consumption, and residential area (mountainous vs coastal). This cross-sectional population-based study clarified the prevalence of DISH in general inhabitants and its significant association with LS and severe KOA.

Spinopelvic alignment of diffuse idiopathic skeletal hyperostosis in lumbar spinal stenosis

PURPOSE

The effect of diffuse idiopathic skeletal hyperostosis (DISH) on spinopelvic alignment in patients with lumbar spinal stenosis (LSS) remains unclear. The aim of this study was to investigate the association between DISH and sagittal spinopelvic alignment in patients undergoing surgery for LSS.

METHODS

A total of 132 patients aged >40 years who required surgical procedures for LSS were investigated. DISH was defined by Resnick's and Mata's criteria on preoperative standing whole-spine radiographs. We investigated the prevalence and localization of DISH and its relation to preoperative clinical symptoms. Spinopelvic alignment was measured by the sagittal C7 plumb line, lumbar lordosis, thoracic kyphosis, and pelvic parameters. The association between DISH and spinopelvic alignment was analyzed using covariance adjustment for age, sex, spondylolisthesis, and degenerative lumbar scoliosis.

RESULTS

The prevalence of DISH was 39.4 % and increased with age. Preoperative symptoms showed no differences, regardless of the presence of DISH. Lumbar and thoracic alignment showed kyphotic change in patients with DISH. Patients with DISH with lower fused vertebral ends at the lumbar level (46 % of DISH) still showed significantly decreased lumbar lordosis (p = 0.014) and decreased sacral slope (p = 0.001) after adjusting for age, sex, spondylolisthesis, and degenerative lumbar scoliosis.

CONCLUSIONS

The prevalence of DISH in patients with LSS was relatively high. Spinopelvic alignment is affected by the presence of DISH, especially in patients with lower fused vertebral ends at the lumbar lesion. These results may offer an explanation for the frequent kyphotic changes in the spine of elderly patients.

Diffuse idiopathic skeletal hyperostosis (DISH): relation to vertebral fractures and bone density

Radiographs and spinal bone mineral density (BMD) were evaluated from 342 elderly men regarding possible effects of diffuse idiopathic skeletal hyperostosis (DISH) on vertebral fractures and densitometry measurements. Prevalent vertebral fractures were more frequent among men with DISH compared to men with no DISH even after fracture prevalence was adjusted for BMD. Paravertebral calcifications should be considered in patients with DISH when interpreting BMD measurements because both dual X-ray absorptiometry (DXA) and quantitative CT (QCT) densitometry may not be reliable.

INTRODUCTION

The purpose of this study is to evaluate the prevalence of DISH in older men and its association with vertebral fractures and with BMD determined by DXA and QCT.

METHODS

Lateral radiographs of the spine were analyzed in a sample of 342 men aged ≥ 65 years participating in the MrOS Study concerning the presence and grade of DISH and vertebral fractures. Lumbar BMD was measured by both DXA (areal, grams per square centimeter) and QCT (volumetric, grams per cubic centimeter). The association between DISH, BMD, and presence of fractures was studied using χ ( 2 ) and t tests.

RESULTS

DISH was present in 52% (178/342) of the men. Men with DISH were older (mean, 75.1 vs 73.3, p < 0.05) and more likely to have prevalent fractures (28% vs 20%, p < p = 0.09). BMD assessed with DXA (1.08 vs 1.00 g/cm(2), p ≤ 0.0001), but not with QCT (0.11 vs 0.11 g/cm3, p = 0.65), was significantly higher in men with DISH compared to men without DISH. Significantly lower BMD of men with both DISH and fractures compared to men with DISH but without fractures was only detected by QCT (-25%, 0.09 vs 0.12, p < 0.05). Both DXA BMD and QCT BMD were significantly higher in severe lumbar DISH (+22% and +31%, p < 0.0001), respectively.

CONCLUSION

DISH was associated with a higher prevalence of vertebral fractures in elderly men. Lumbar ossifications related to DISH should be considered when interpreting BMD measurements to predict their fracture risk.

Diffuse idiopathic skeletal hyperostosis and its relation to back pain among older men: the MrOS Study

OBJECTIVES

To estimate the prevalence of diffuse idiopathic skeletal hyperostosis (DISH) in a cross-sectional study of elderly men age 65 to 100 years and to examine back and neck pain as possible correlates of DISH.

METHODS

DISH was defined using Resnick's criteria and scored according to Mata on lateral spine radiographs of 298 randomly selected participants from the MrOS Study. Standardized self-reported questionnaires were used to assess the frequency and severity of back and neck pain, and the relation of these to DISH status was estimated with χ(2) tests, as well as prevalence ratios and 95% confidence intervals using log-binomial regression models.

RESULTS

DISH was observed in 126 older men (42%), increased with age (30%, 39%, 48%, and 56% for ages 65-69, 70-74, 75-79, and ≥80 respectively), and was positively associated with body mass index (BMI) (P = 0.04) and blood pressure (P = 0.02). Significantly less back pain in the past 12 months was reported among men with DISH as compared to men without (59% vs 71%, P = 0.03), which remained after adjustment for age, BMI, and blood pressure (prevalence ratios = 0.73, 95% confidence interval = 0.57-0.95). Back pain severity (P = 0.07) and frequency (P = 0.06) were also less frequent among men with DISH compared to men without, whereas reported neck pain was similar between groups (P = 0.39).

CONCLUSIONS

Among community-dwelling elderly men, DISH prevalence is high, increases with age, and is positively associated with BMI and blood pressure. Frequency of self-reported back pain over the past 12 months was lower in older men with DISH as compared to those without DISH.

Diffuse idiopathic skeletal hyperostosis: musculoskeletal manifestations

Diffuse idiopathic skeletal hyperostosis (DISH) is a common disorder of unknown etiology that is characterized by back pain and spinal stiffness. There may be mild pain if ankylosis has occurred. The condition is recognized radiographically by the presence of "flowing" ossification along the anterolateral margins of at least four contiguous vertebrae and the absence of changes of spondyloarthropathy or degenerative spondylosis. Even in patients who present with either lumbar or cervical complaints, radiographic findings are almost universally seen on the right side of the thoracic spine. Thus, radiographic examination of this area is critical when attempting to establish a diagnosis of DISH. The potential sequelae of hyperostosis in the cervical and lumbar spine include lumbar stenosis, dysphagia, cervical myelopathy, and dense spinal cord injury resulting from even minor trauma. There may be a delay in diagnosis of spinal fractures in a patient with DISH because the patient often has a baseline level of spinal pain and because the injury may be relatively trivial. The incidence of delayed neurologic injury due to such fractures is high as a result of unrecognized instability and subsequent deterioration. Extraspinal manifestations are also numerous and include an increased risk of heterotopic ossification after total hip arthroplasty. Prophylaxis to prevent heterotopic ossification may be indicated for these patients.