Where's the break? Critique of radiographic vertebral fracture diagnostic methods

Improvement of bone mineral density and new vertebral fractures during 8 years of TNF-α inhibition in patients with axial spondyloarthritis

OBJECTIVE

In our prospective cohort with standardized bi-annual measurements of bone mineral density (BMD) and spinal radiographs, we evaluated the long-term course of BMD and the development of radiographic vertebral fractures (VFs) during 8 years of TNFi treatment in patients with radiographic axial spondyloarthritis (r-axSpA).

METHODS

Consecutive axSpA patients from the GLAS cohort receiving TNFi for ≥8 years were included. Patients who received anti-osteoporotic treatment were excluded. Lumbar spine (LS) BMD was assessed at baseline, 1 year and bi-annually using DEXA. Radiographic VFs were evaluated using the Genant classification.

RESULTS

126 axSpA patients were included; 75 % male, mean age 42 ± 11 years, ASDAS 3.8 ± 0.8, median LS BMD Z-score -0.5 (IQR -1.4-0.7) and 20 % had radiographic VFs at baseline. Disease activity improved rapidly and sustained. LS BMD Z-score improved significantly up to 4 years compared to the previous time point and sustained thereafter. Median percentage of improvement compared to baseline was 8.9 % (2.8-15.8) and 7.2 % (2.2-14.7) after 4 and 8 years, respectively. Of 90 patients with baseline and 8-year radiographs, 14 (16 %) developed new VFs and 5 (6 %) showed an increase in severity of existing VFs. Of all 44 VFs present at 8 years, 30 % were grade 2 (n = 12) or grade 3 (n = 1).

CONCLUSION

In r-axSpA patients treated with TNFi for 8 years, LS BMD Z-score increased significantly, especially during the first 4 year of treatment. Radiographic VFs continued to develop or progressed, irrespective of improvement in BMD. Therefore, clinical attention for trabecular bone loss is important in daily clinical practice.

Sedentary behavior does not predict low BMD nor fracture-population-based Canadian Multicentre Osteoporosis Study

Sedentary behavior (SB) or sitting is associated with multiple unfavorable health outcomes. Bone tissue responds to imposed gravitational and muscular strain with there being some evidence suggesting a causal link between SB and poor bone health. However, there are no population-based data on the longitudinal relationship between SB, bone change, and incidence of fragility fractures. This study aimed to examine the associations of sitting/SB (defined as daily sitting time), areal BMD (by DXA), and incident low trauma (fragility) osteoporotic fractures (excluding hands, feet, face, and head). We measured baseline (1995-7) and 10-yr self-reported SB, femoral neck (FN), total hip (TH), and lumbar spine (L1-L4) BMD in 5708 women and 2564 men aged 25 to 80+ yr from the population-based, nationwide, 9-center Canadian Multicentre Osteoporosis Study. Incident 10-yr fragility fracture data were obtained from 4624 participants; >80% of fractures were objectively confirmed by medical records or radiology reports. Vertebral fractures were confirmed by qualitative morphological methods. All analyses were stratified by sex. Multivariable regression models assessed SB-BMD relationships; Cox proportional models were fit for fracture risk. Models were adjusted for age, height, BMI, physical activity, and sex-specific covariates. Women in third/fourth quartiles had lower adjusted FN BMD versus women with the least SB (first quartile); women in the SB third quartile had lower adjusted TH BMD. Men in the SB third quartile had lower adjusted FN BMD than those in SB first quartile. Neither baseline nor stable 10-yr SB was related to BMD change nor to incident fragility fractures. Increased sitting (SB) in this large, population-based cohort was associated with lower baseline FN BMD. Stable SB was not associated with 10-yr BMD loss nor increased fragility fracture. In conclusion, habitual adult SB was not associated with subsequent loss of BMD nor increased risk of fracture.

Chest radiograph prevalence of vertebral deformity among young and middle-aged population of mixed city dwellers and rural residents

Background

To interpret the importance of minimal and mild vertebral deformities (VDs) among elderly subjects, we need to know their prevalence among mostly non-osteoporotic subjects.

Methods

We retrospectively analyzed VDs among 408 female and 374 male patients who had lateral chest radiographs due to mild illness or for routine healthcheck, all with indications other than spine disorders or metabolic disorders. The study subjects were divided into four age groups, i.e., ≤20, 20-34, 35-44, and ≥45 years. For those aged >20 years, 27.2% females had family roots from farming communities, and 26.4% males had the history of being a farmer or physical laborer (this was 36.1% for males aged ≥45 years). Fracture shaped vertebral deformities (FSVDs) were VDs radiographically indistinguishable from vertebral fracture. Acquired short vertebrae were those with decreased vertebral anterior and middle heights, while without anterior wedging or bi-concave changes, and the diagnosis required at least two adjacent short vertebrae in the same subject.

Results

Congenital VDs were observed in four cases (three males, one female). In the age group of ≤20, 20-34, 35-44, and ≥45 years, females had any FSVD prevalence of 13.4%, 8.3%, 11.8%, 25.8% respectively, while the prevalence was 29.3%, 26%, 34.3%, 44.8% respectively for males. From the female ≤20 years group to the 21-34 years group, cases involved multiple vertebrae decreased from 53.8% to 16.7%. For cases ≤34 years, no female case had ≥ mild FSVD (which was defined to have ≥20% vertebral height loss), while five male cases had ≥ mild FSVD. For the 35-44 years group, vertebral endplate depression was noted among 2.0% of the females and 2.9% of the males. Among the cases aged ≤44 years, there was only one male and one female had acquired short vertebrae. For the male cases, acquired short vertebrae prevalence was 15.6% in the group of ≥45 years.

Conclusions

FSVD is common among young and middle-aged population (≤44 years) assumed with normal bone strength, and with a higher FSVD prevalence among men. FSVD may heal among younger subjects, and physical labor may increase VD prevalence.

Zoledronate Reduces Height Loss Independently of Vertebral Fracture Occurrence in a Randomized Trial in Osteopenic Older Women

Vertebral fractures are associated with height loss, reduced quality of life, and increased mortality and are an important endpoint for osteoporosis trials. However, height loss is associated with quality of life and mortality independent of associations with fracture. We have used data from a recent 6-year trial of zoledronate in 2000 osteopenic women aged >65 years to assess the impact of the semiquantitative and quantitative components of the definition of vertebral fracture on the outcome of that trial, to determine what factors impacted on height loss and to test whether height loss can be used as a surrogate for vertebral fracture incidence. In the trial protocol, an incident vertebral fracture was defined as a change in Genant grade plus both a 20% and 4 mm decrease in a vertebral height. The addition of the quantitative criteria reduced the number of fractures detected but did not change the size of the anti-fracture effect (odds ratios of 0.49 versus 0.45) nor the width of the confidence intervals for the odds ratios. Multivariate analysis of baseline predictors of height change showed that age accelerated height loss (p < 0.0001) and zoledronate reduced it (p = 0.0001). Incident vertebral fracture increased height loss (p = 0.0005) but accounted for only 0.7% of the variance in height change, so fracture could not be reliably inferred from height loss. In women without incident vertebral fractures, height loss was still reduced by zoledronate (height change: zoledronate, -1.23; placebo -1.51 mm/yr, p < 0.0001). This likely indicates that zoledronate prevents a subtle but widespread loss of vertebral body heights not detected by vertebral morphometry. Because height loss is associated with quality of life and mortality independent of associations with fracture, it is possible that zoledronate impacts on these endpoints via its effects on vertebral body integrity. © 2022 American Society for Bone and Mineral Research (ASBMR).

Definition of normal vertebral morphometry using NHANES‐II radiographs

A robust definition of normal vertebral morphometry is required to confidently identify abnormalities such as fractures. The Second National Health and Nutrition Examination Survey (NHANES‐II) collected a nationwide probability sample to document the health status of the United States. Over 10,000 lateral cervical spine and 7,000 lateral lumbar spine X‐rays were collected. Demographic, anthropometric, health, and medical history data were also collected. The coordinates of the vertebral body corners were obtained for each lumbar and cervical vertebra using previously validated, automated technology consisting of a pipeline of neural networks and coded logic. These landmarks were used to calculate six vertebral body morphometry metrics. Descriptive statistics were generated and used to identify and trim outliers from the data. Descriptive statistics were tabulated using the trimmed data for use in quantifying deviation from average for each metric. The dependency of these metrics on sex, age, race, nation of origin, height, weight, and body mass index (BMI) was also assessed. There was low variation in vertebral morphometry after accounting for vertebrae (eg, L1, L2), and the R² was high for ANOVAs. Excluding outliers, age, sex, race, nation of origin, height, weight, and BMI were statistically significant for most of the variables, though the F‐statistic was very small compared to that for vertebral level. Excluding all variables except vertebra changed the ANOVA R² very little. Reference data were generated that could be used to produce standardized metrics in units of SD from mean. This allows for easy identification of abnormalities resulting from vertebral fractures, atypical vertebral body morphometries, and other congenital or degenerative conditions. Standardized metrics also remove the effect of vertebral level, facilitating easy interpretation and enabling data for all vertebrae to be pooled in research studies. © 2022 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

Imaging of Metabolic Bone Diseases: The Spine View, Part II

Metabolic bone diseases comprise a wide spectrum. Osteoporosis, the most frequent, characteristically involves the spine, with a high impact on health care systems and on the morbidity of patients due to the occurrence of vertebral fractures (VFs).Part II of this review completes an overview of state-of-the-art techniques on the imaging of metabolic bone diseases of the spine, focusing on specific populations and future perspectives. We address the relevance of diagnosis and current status on VF assessment and quantification. We also analyze the diagnostic techniques in the pediatric population and then review the assessment of body composition around the spine and its potential application. We conclude with a discussion of the future of osteoporosis screening, through opportunistic diagnosis and the application of artificial intelligence.

CT detects more osteoporotic endplate depressions than radiograph: a descriptive comparison of 76 vertebrae

This study analyzed elderly women who had chest radiograph and chest CT with indications other than spine disorders. Using CT images as reference, the study demonstrates that radiograph can miss a high portion of mild endplate depression. Detection of endplate depression is confounded by the limitation of projectional overlay for radiograph.

INTRODUCTION

The definition of radiographic OVF (osteoporotic vertebral fracture) remains controversial. Some authors suggest all OVFs should demonstrate endplate fracture/depression on radiograph. Using CT image as the reference, our study tests the hypothesis that a considerable portion of endplate depressions not seen on radiograph can be detected on CT.

METHODS

We retrospectively analyzed 46 female cases (age: 67-94 years) who had both chest radiography and chest CT with indications other than spine disorders. Sixty-six "vertebrae of interest" were identified on radiograph; then, CT images were read side-by-side with lateral chest radiograph.

RESULTS

Thirty-eight vertebrae (38/66) had anterior wedging deformity with height loss of < 20% while without radiographic endplate depression. Among them, 28 vertebrae had endplate depression and 8 vertebrae had no endplate depression on CT, while 2 vertebrae with "very" minimal deformity were read as normal on CT. In 9 vertebrae (9/66) with anterior wedging and height loss of ≥ 20%, all had additional endplate depression seen on CT. Five vertebrae (5/66) had ambiguous endplate depression on radiograph, 3 had endplate depression on CT while the other 2 vertebrae in one patient were false positive due to X-ray projection. There were 14 short height vertebrae (14/66) where middle and anterior heights were reduced to the same extent while did not show apparent anterior wedging or bi-concaving. Four cases each had one short height vertebra, and all had endplate depression on CT. Another 4 cases had 2, 2, 3, and 3 adjacent short height vertebrae, respectively, and all did not show endplate depression on CT. In addition, inspection of spine CT showed 10 vertebrae in 9 cases appeared normal on radiograph while demonstrated endplate depression on CT.

CONCLUSION

With CT images as reference, radiograph can miss a high portion of mild endplate depressions.