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

BACKGROUND: Differentiating between degenerative disc disease (DDD), diffuse idiopathic skeletal hyperostosis (DISH), and axial spondyloarthritis (axSpA) represents a diagnostic challenge in patients with low back pain (LBP). We aimed to evaluate the distribution of inflammatory and degenerative imaging features in a real-life cohort of LBP patients referred to a tertiary university rheumatology center. METHODS: In a retrospective cross-sectional analysis of patients referred for LBP, demographics, symptom information, and available imaging were collected. SpA-like changes were considered in the spine in the presence of one of the following lesions typically related to SpA: erosions, sclerosis, squaring, and syndesmophytes on conventional radiographs (CR) and bone marrow oedema (BMO), erosions, sclerosis, and fat lesions (FL) on MRI. SIJ CR were graded per New York criteria; on MRIs, SIJs were evaluated by quadrant for BMO, erosions, FL, sclerosis and ankylosis, similar to the approach used by the Berlin SIJ MRI scoring system. The final diagnosis made by the rheumatologist was the gold standard. Data were presented descriptively, by patient and by quadrant, and compared among the three diagnosis groups. RESULTS: Among 136 referred patients, 71 had DDD, 38 DISH, and 27 axSpA; median age 62 years [IQR55-73], 63% males. On CR, SpA-like changes were significantly higher in axSpA in the lumbar (50%, vs. DDD 23%, DISH 22%), in DISH in the thoracic (28%, vs. DDD 8%, axSpA 12%), and in DDD in the cervical spine (67% vs. DISH 0%, axSpA 33%). On MRI, BMO was significantly higher in DISH in the thoracic (37%, vs. DDD 22%, axSpA 5%) and equally distributed in the lumbar spine (35-42%). FL were significantly more frequently identified in DISH and axSpA in the thoracic (56% and 52%) and DDD and axSpA in the lumbar spine (65% and 74%, respectively). Degenerative changes were frequent in the three groups. Sacroiliitis (NY criteria) was identified in 49% (axSpA 76%, DDD 48%, DISH 29%). CONCLUSION: A significant overlap was found among DDD, DISH, and axSpA for inflammatory and degenerative imaging features. Particularly, SpA-like spine CR features were found in one-fourth of patients with DISH, and MRI BMO was found in one-third of those patients.

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.

High prevalence of diffuse idiopathic skeletal hyperostosis (DISH) among obese young patients - A retrospective observational study.

OBJECTIVE: Diffuse idiopathic skeletal hyperostosis (DISH) is characterized by ossification of ligaments and entheses, and most commonly affects the spinal column. The prevalence of DISH is increasing with age and is considered uncommon before the age of 50 years, with an estimated prevalence of less than 5 %. DISH is known to be highly associated with metabolic syndrome and obesity. We aim to assess the prevalence of DISH among young (≤50 yr.) patients suffering from severe obesity (BMI of 35 kg/m2 or higher). METHODS: A retrospective analysis assessing chest and spine radiographs (including Computed Tomography, CT) of patients with BMI≥35 visiting the bariatric ambulatory clinic in an academic medical center from 2013 to 2022. Patients included in the analysis were 31-50 years old. Diagnosis of DISH was made according to the Resnick criteria. The prevalence of DISH was calculated. Demographic, clinical and laboratory data were collected and compared between the DISH and non-DISH groups. RESULTS: 183 young (mean age: 40.4; 118 females, 64.2 %) obese (BMI median: 40.6; range 35-73) patients were included in the radiographic review. DISH was diagnosed in 33 patients (18.0 %; 95 % CI: 13.1-24.2 %) which was significantly higher than the expected 10 % (Z = 3.62, p<.001); another 8 patients (4.4 %; 95 % CI: 2.2-8.4 %) were considered as "near DISH" (not fulfilling yet the Resnick criteria) as it represents a pre-disease state. Patients diagnosed with DISH were significantly older than patients without DISH (t = 4.54, p<.001), as the prevalence of DISH increased by age (linear association=14.95, p<.001). There was a statistically significantly higher prevalence of hypertension (χ2 = 8.30, p<.004), smoking (χ2 = 4.69, p<.03) and OSA (χ2 = 6.16, p<.013) in the DISH group as compared to their non-DISH counterparts. CONCLUSION: The prevalence of DISH among obese young patients was 18 %, which is much higher than in the general population. Early-onset DISH should be regarded as a musculoskeletal obesity-related complication.

Long-term effects of diffuse idiopathic skeletal hyperostosis on physical function: A longitudinal analysis.

BACKGROUND: Cross-sectional studies on diffuse idiopathic skeletal hyperostosis have focused on its incidence and related factors. However, the long-term changes caused by the disease remain unclear. This longitudinal cohort study aimed to elucidate the progression of diffuse idiopathic skeletal hyperostosis and its effects on physical function, health-related quality of life, and spinal alignment. METHODS: We recruited 255 older adults (87 men and 168 women; average age, 71.3 years in 2014) who attended local health checkups in 2014 and 2020. Height, body weight, body mass index, blood pressure, grip strength, functional reach, and bone mineral density were measured. The prevalence, location, number of ossified contiguous vertebrae, and spinopelvic parameters were estimated using whole-spine standing radiographs. For health-related quality of life assessment, the Oswestry disability index and EuroQuol-5D were obtained. We performed a 1:1 case-control study with age and sex-matched patients with and without diffuse idiopathic skeletal hyperostosis and analyzed progression over a 6-year period. RESULTS: In 2014, 39 (15.3%) of 255 patients were diagnosed with diffuse idiopathic skeletal hyperostosis (24 males and 15 females), which occurred more frequently in the elderly and males. In 2020, 12 (4.3%) patients were newly diagnosed with diffuse idiopathic skeletal hyperostosis, and 28 (71.7%) of 39 patients diagnosed in 2014 showed varying degrees of progression. Compared with age- and sex-matched patients without diffuse idiopathic skeletal hyperostosis, patients with the condition had higher body mass index and lumbar bone mineral density, larger sagittal vertical axis, and greater T1-pelvic angle. Changes in physical function and spinal-pelvic parameters during the 6-year period did not differ between the groups. CONCLUSIONS: Over a 6-year period, the prevalence of diffuse idiopathic skeletal hyperostosis increased by 4.3%, and it progressed in 71.7% of patients. However, it had little effect on longitudinal physical function, health-related quality of life, and spinopelvic parameters in older adults.

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.

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.

Complications of the Rigid Spine.

We present a short overview of the most common causes and imaging findings of a rigid spine including long-standing spondylarthritis, diffuse idiopathic skeletal hyperostosis, and the less common ossification of the posterior longitudinal ligament. The article also focuses on the pathogenesis and imaging findings of acute complications of the rigid spine due to fractures. These fractures may occur even after minor trauma and are difficult to detect on initial radiographs, resulting in a delayed diagnosis. They are often unstable with a high risk of severe neurologic complications, leading to high morbidity and mortality both in the initial phase and in the months following the fracture. Because the negative predictive value of conventional radiography is low, every patient with a rigid spine with newly appearing pain should be referred for subsequent cross-sectional imaging.

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

OBJECTIVE: Diffuse idiopathic skeletal hyperostosis (DISH) is characterized by osteophytes in the anterior vertebrae, and the presence of aorta may have an impact on their formation. However, the anatomical positional relationship between the aorta and osteophytes in patients with DISH remains controversial. This study aimed to evaluate the position of osteophytes in relation to aorta in DISH, and the influence of aortic pulsation on the formation of osteophytes from the perspective of morphology. METHODS: We conducted a retrospective review of 101 patients diagnosed with DISH and symptomatic lumbar spinal stenosis between June 2018 and December 2021. A total of 637 segments with heterotopic ossification in DISH were used for quantitative measurements on CT scans. The Cartesian coordinate system was built up on the axial CT scans to reflect the relative position between aorta and osteophytes. Osteophytes were divided into adjacent aorta group (AD group) and non-adjacent aorta group (N-AD group). In terms of the morphology, osteophytes in the AD group were further divided into convex, flat, and concave types. The relative position between aorta and osteophytes, and the aorta-osteophyte distance and morphology of osteophytes were compared. Univariate analysis of variance was performed for multiple groups, and two independent-samples t-tests were used for two groups. RESULTS: From T5 to L4, aorta gradually descended from left side to middle of vertebrae, and osteophytes gradually shifted from right side of vertebrae (T5-T10) to bilateral sides (T11-L4). Of 637 osteophytes in DISH, 60.1% (383/637) were in AD group, including convex type 0.6% (4/637), flat type 34.7% (221/637), and concave type 24.8% (158/637). The N-AD group accounted for 39.9% (254/637). Flat osteophytes were concentrated in T5-T12, while concave osteophytes in T11-L4. Overall, the aorta-osteophyte distance of concave type was significantly smaller than that of flat type. CONCLUSION: Osteophytes are not always located on the right side of vertebrae, but move with the position of the descending aorta. Furthermore, the morphology of osteophytes varies by vertebral segment in DISH, which is related to aorta descending anteriorly in the spine.

Progressive spinal destruction secondary to minimal vertebral fracture in a patient with diffuse idiopathic skeletal hyperostosis: a case report.

Early operative fixation is widely recognized as essential for managing spinal fractures in patients with diffuse idiopathic skeletal hyperostosis (DISH). However, no report to date has addressed the occurrence of minimal vertebral fractures diagnosable only through magnetic resonance imaging (MRI) in these patients and the associated temporal changes in the fracture site. In this report, we describe a rare clinical case involving an 81-year-old man who developed progressive spinal destruction secondary to a minimal vertebral fracture. MRI showed minimum-intensity changes in the T12 vertebral body, whereas X-ray and computed tomography examinations showed DISH and no spinal fracture. Despite experiencing severe low back pain, the patient did not undergo operative therapy for 2 months, resulting in progressive spinal destruction. Spinal fusion with posterior instrumentation was performed, and the patient was followed for 1 year with no symptoms and good functional status. This case emphasizes the importance of clinicians being cautious to avoid overlooking and undervaluing minimal vertebral fractures diagnosable only through MRI in patients with DISH.

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

OBJECTIVES: To determine the incidence of spinal hematoma and its relation to neurological deficit after trauma in patients with spinal ankylosis from diffuse idiopathic skeletal hyperostosis (DISH). MATERIALS AND METHODS: A retrospective review of 2256 urgent or emergency MRI referrals over a period of 8 years and nine months revealed 70 DISH patients who underwent CT and MRI scans of the spine. Spinal hematoma was the primary outcome. Additional variables were spinal cord impingement, spinal cord injury (SCI), trauma mechanism, fracture type, spinal canal narrowing, treatment type, and Frankel grades during injury, before and after treatment. Two trauma radiologists reviewed MRI scans blinded to initial reports. RESULTS: Of 70 post-traumatic patients (54 men, median age 73, IQR 66-81) with ankylosis of the spine from DISH, 34 (49%) had spinal epidural hematoma (SEH) and 3 (4%) had spinal subdural hematoma, 47 (67%) had spinal cord impingement, and 43 (61%) had SCI. Ground-level fall (69%) was the most common trauma mechanism. A transverse, AO classification type B spine fracture (39%) through the vertebral body was the most common injury type. Spinal canal narrowing (p < .001) correlated and spinal cord impingement (p = .004) associated with Frankel grade before treatment. Of 34 patients with SEH, one, treated conservatively, developed SCI. CONCLUSIONS: SEH is a common complication after low-energy trauma in patients with spinal ankylosis from DISH. SEH causing spinal cord impingement may progress to SCI if not treated by decompression. CLINICAL RELEVANCE STATEMENT: Low-energy trauma may cause unstable spinal fractures in patients with spinal ankylosis caused by DISH. The diagnosis of spinal cord impingement or injury requires MRI, especially for the exclusion of spinal hematoma requiring surgical evacuation. KEY POINTS: • Spinal epidural hematoma is a common complication in post-traumatic patients with spinal ankylosis from DISH. • Most fractures and associated spinal hematomas in patients with spinal ankylosis from DISH result from low-energy trauma. • Spinal hematoma can cause spinal cord impingement, which may lead to SCI if not treated by decompression.

The Effect of Posterior Lumbar Interbody Fusion in Lumbar Spine Stenosis with Diffuse Idiopathic Skeletal Hyperostosis: A Finite Element Analysis.

OBJECTIVE: Lumbar spinal canal stenosis (LSS) with diffuse idiopathic skeletal hyperostosis (DISH) can require revision surgery because of the intervertebral instability after decompression. However, there is a lack of mechanical analyses for decompression procedures for LSS with DISH. METHODS: This study used a validated, three-dimensional finite element model of an L1-L5 lumbar spine, L1-L4 DISH, pelvis, and femurs to compare the biomechanical parameters (range of motion [ROM], intervertebral disc, hip joint, and instrumentation stresses) with an L5-sacrum (L5-S) and L4-S posterior lumbar interbody fusion (PLIF). A pure moment with a compressive follower load was applied to these models. RESULTS: ROM of L5-S and L4-S PLIF models decreased by more than 50% at L4-L5, respectively, and decreased by more than 15% at L1-S compared with the DISH model in all motions. The L4-L5 nucleus stress of the L5-S PLIF increased by more than 14% compared with the DISH model. In all motions, the hip stress of DISH, L5-S, and L4-S PLIF had very small differences. The sacroiliac joint stress of L5-S and L4-S PLIF models decreased by more than 15% compared with the DISH model. The stress values of the screws and rods in the L4-S PLIF model was higher than in the L5-S PLIF model. CONCLUSIONS: The concentration of stress because of DISH may influence adjacent segment disease on the nonunited segment of PLIF. A shorter-level lumbar interbody fixation is recommended to preserve ROM; however, it should be used with caution because it could provoke adjacent segment disease.

Diffuse idiopathic skeletal hyperostosis (DISH) and trabecular bone score (TBS) in postmenopausal women: The Camargo cohort.

OBJECTIVES: The potential relationship between diffuse idiopathic skeletal hyperostosis (DISH) and bone microstructure has not been studied in women. We aimed to assess the association between the trabecular bone score (TBS) and DISH in postmenopausal women, as well as the role of other parameters related to bone metabolism, such as bone mineral density (BMD), calciotropic hormones, and bone remodeling markers. METHODS: Cross-sectional study, nested in a prospective population-based cohort (Camargo cohort). Clinical covariates, DISH, TBS, vitamin D, parathormone, BMD and serum bone turnover markers, were analyzed. RESULTS: We have included 1545 postmenopausal women (mean age, 62±9 years). Those with DISH (n = 152; 8.2%) were older and had a significantly higher prevalence of obesity, metabolic syndrome, hypertension, and type 2 diabetes mellitus (p<0.05). Moreover, they had lower TBS values (p = 0.0001) despite having a higher lumbar spine BMD (p<0.0001) and a higher prevalence of vertebral fractures than women without DISH (28.6% vs. 15.1%; p = 0.002). When analyzing DISH through Schlapbach grades, women without DISH had a median TBS value consistent with a normal trabecular structure while the values for women with DISH from grades 1 to 3 were consistent with a partially degraded trabecular structure. Women with vertebral fractures and DISH had a mean TBS corresponding to a degraded trabecular structure (1.219±0.1). After adjusting for confounders, the estimated TBS means were 1.272 (1.253-1.290) in the DISH group, and 1.334 (1.328-1.339) in the NDISH group (p<0.0001). CONCLUSION: An association between DISH and TBS has been shown in postmenopausal women, in which hyperostosis has been significantly and consistently related to trabecular degradation and, therefore, to deterioration in bone quality after adjusting for confounding variables.

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

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

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.

Prognostic factors of balloon kyphoplasty for osteoporotic vertebral fractures with diffuse idiopathic skeletal hyperostosis.

OBJECTIVE: The authors aimed to determine the poor prognostic factors of balloon kyphoplasty for the treatment of fractures of the most distal or distal-adjacent vertebrae in ankylosing spines with diffuse idiopathic skeletal hyperostosis (DISH). METHODS: Eighty-nine patients with fractures of the most distal or distal-adjacent vertebrae of ankylosing spines with DISH were included and divided into two groups: those with (n = 51) and without (n = 38) bone healing 6 months postoperatively. Clinical evaluation included age, sex, time from onset to surgery, the visual analog scale score for low-back pain, and the Oswestry Disability Index (ODI). The VAS scores and ODI were measured both preoperatively and at 6 months postoperatively. Radiological evaluations included bone density; wedge angles of the fractured vertebrae in the supine and sitting positions on lateral radiographs; differences in the wedge angles (change in wedge angle); and the amount of polymethylmethacrylate used. RESULTS: The preoperative ODI, vertebral wedge angles in the supine and sitting positions, change in wedge angle, and amount of polymethylmethacrylate were significantly different between the two groups and were significantly associated with delayed bone healing in univariate logistic regression analysis. Multivariate logistic regression analysis showed that only a change in the wedge angle was significantly associated with delayed healing, with a cutoff value of 10°, sensitivity of 84.2%, and specificity of 82.4%. CONCLUSIONS: Treatment with balloon kyphoplasty alone should be avoided in patients with a difference ≥ 10° in the wedge angle of the fractured vertebrae between the supine and sitting positions.