Vertebral dimension differences between Caucasian populations, and between Caucasians and Japanese

Utility of White Light Scanning as an Alternative to Computed Tomography to Evaluate Severity of Pectus Excavatum Deformity

BACKGROUND

Pectus excavatum (PE) severity and surgical candidacy are determined by computed tomography (CT)-delineated Haller Index (HI) and Correction Index (CI). White light scanning (WLS) has been proposed as a non-ionizing alternative. The purpose of this retrospective study is to create models to determine PE severity using WLS as a non-ionizing alternative to CT.

METHODS

Between November 2015 and February 2023, CT and WLS were performed for children ≤18 years undergoing evaluation at a high-volume, chest-wall deformity clinic. Separate quadratic discriminate analysis models were developed to predict CT HI ≥ 3.25 and CT CI ≥ 28% indicating surgical candidacy. Two bootstrap forest models were trained on WLS measurements and patient demographics to predict CT HI and CT CI values then compared to actual index values by intraclass correlation coefficient (ICC).

RESULTS

In total, 242 patients were enrolled (86.4% male, mean [SD] age 15.2 [1.3] years). Quadratic discriminate analysis models predicted CT HI ≥ 3.25 with specificity = 91.7%, PPV = 97.7% (AUC = 0.91), and CT CI ≥ 28% with specificity = 92.3%, PPV = 93.5% (AUC = 0.84). Bootstrap forest model predicted CT HI with training dataset ICC (95% CI) = 0.91 (0.88-0.93, R2 = 0.85) and test dataset ICC (95% CI) = 0.86 (0.71-0.94, R2 = 0.77). For CT CI, training dataset ICC (95% CI) = 0.91 (0.81-0.93, R2 = 0.86) and test dataset ICC (95% CI) = 0.75 (0.50-0.88, R2 = 0.63).

CONCLUSIONS

Using noninvasive and nonionizing WLS imaging, we can predict PE severity at surgical threshold with high specificity obviating the need for CT. Furthermore, we can predict actual CT HI and CI with moderate-excellent reliability. We anticipate this point-of-care tool to obviate the need for most cross-sectional imaging during surgical evaluation of PE.

LEVEL OF EVIDENCE

Level III.

STUDY TYPE

Study of Diagnostic Test.

Clinicosocial determinants of hospital stay following cervical decompression: A public healthcare perspective and machine learning model

OBJECTIVE

Post-operative length of hospital stay (LOS) is a valuable measure for monitoring quality of care provision, patient recovery, and guiding hospital resource management. But the impact of patient ethnicity, socio-economic deprivation as measured by the indices of multiple deprivation (IMD), and pre-existing health conditions on LOS post-anterior cervical decompression and fusion (ACDF) is under-researched in public healthcare settings.

METHODS

From 2013 to 2023, a retrospective study at a single center reviewed all ACDF procedures. We analyzed 14 non-clinical predictors-including demographics, comorbidities, and socio-economic status-to forecast a categorized LOS: short (≤2 days), medium (2-3 days), or long (>3 days). Three machine learning (ML) models were developed and assessed for their prediction reliability.

RESULTS

2033 ACDF patients were analyzed; 79.44 % had a LOS ≤ 2 days. Significant predictors of LOS included patient sex (HR:0.81[0.74-0.88], p < 0.005), IMD decile (HR:1.38[1.24-1.53], p < 0.005), smoking (HR:1.24[1.12-1.38], p < 0.005), DM (HR:0.70[0.59-0.84], p < 0.005), and COPD (HR:0.66, p = 0.01). Asian patients had the highest mean LOS (p = 0.003). Testing on 407 patients, the XGBoost model achieved 80.95 % accuracy, 71.52 % sensitivity, 85.76 % specificity, 71.52 % positive predictive value, and a micro F1 score of 0.715. This model is available at: https://acdflos.streamlit.app.

CONCLUSIONS

Utilizing non-clinical pre-operative parameters such as patient ethnicity, socio-economic deprivation index, and baseline comorbidities, our ML model effectively predicts postoperative LOS for patient undergoing ACDF surgeries. Yet, as the healthcare landscape evolves, such tools will require further refinement to integrate peri and post-operative variables, ensuring a holistic decision support tool.

The Influence of the Weight of the Backpack on the Biomechanics of the Child and Adolescent: A Systematic Review and Meta-analysis With a Meta-Regression

PURPOSE

To evaluate and explore the influence of the weight of a backpack on standing posture and gait in children and adolescents.

METHODS

We conducted a search of MEDLINE (PubMed), Cochrane Library, Cumulative Index to Nursing and Allied Health Literature (CINAHL), and Web of Science, with the last search in July 2021. Standardized mean differences (SMD) and 95% confidence intervals were calculated for relevant outcomes and were pooled in a meta-analysis using the random-effects model. The participants were healthy children or adolescents. The outcomes were postural variables, spatiotemporal gait variables, gait kinematics, and muscle activity. We analyzed the influence of a loaded backpack on posture while standing and spatiotemporal and kinematic variables while walking. We used GRADE, Risk of Bias 2, ROBINS-I, MINORS, and PEDro scales to rate the quality, certainty, and applicability of the evidence.

RESULTS

Wearing a loaded backpack induces a significant increase of the craniohorizontal angle while standing and a decrease of walking speed and stride length while walking. Only the craniovertebral angle had a significant relationship with the weight of the backpack.

CONCLUSIONS

Wearing a backpack induces postural changes while standing and affects gait in children and adolescents; however, almost all the changes are not related to the backpack weight.

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.

Equivalent values between anterior vertebral height, wedge ratio, and wedge angle in osteoporotic vertebral fractures

INTRODUCTION

Vertebral mobility (V-mobility) has been used to diagnose fresh osteoporotic vertebral fractures (OVFs), and determine or predict bone union by setting cutoff values for these purposes. V-mobility is defined as the difference in shape of vertebral bodies between lateral radiographs taken in weight-bearing and non-weight-bearing positions. The parameters for V-mobility have varied in previous reports among anterior vertebral height (Ha, mm), wedge ratio (WR, %), and wedge angle (WA, degrees). The present study aimed to clarify WR and WA equivalent to Ha of 1.0 mm, and to compare the reported cutoff values for V-mobility presented as Ha, WR, or WA.

MATERIALS AND METHODS

Lateral radiographs of 446 normal vertebrae (grade 0) and 146 deformed vertebrae (grade 1-3) from T11 to L2 were obtained from 183 female patients aged > 60 years. WR (%) values equivalent to Ha of 1.0 mm were calculated by Ha (1.0 mm)/Hp × 100 (Hp: posterior vertebral height). Corresponding WA values were calculated by trigonometric function using vertebral dimensions.

RESULTS

The mean WR values equivalent to Ha of 1.0 mm in the vertebrae from T11 to L2 were 3.2%, 3.2%, 3.5%, and 3.7% for grades 0, 1, 2, and 3, respectively, and the corresponding WA values were 1.6°, 1.6°, 1.5°, and 1.4°.

CONCLUSION

The equivalent values for V-mobility presented as Ha, WR, and WA were obtained. The mean WR and WA values equivalent to Ha of 1.0 mm in grade 1-3 vertebrae were 3.5% and 1.5°, respectively.

The Radiology of Osteoporotic Vertebral Fractures Revisited

Until recently there has been little evidence available to validate any method by which to make an accurate diagnosis of an osteoporotic vertebral fractures (OVFs) from plain radiographs. In part this reflects a lack of a completely satisfactory "gold standard," but primarily it relates to the absence of well-designed prospective studies in this context. Historically, OVFs were recognized by evidence of macroscopic structural failure in vertebrae using the criteria applied elsewhere in the skeleton. This comprised altered alignment, fragmentation, cortical disruptions, and breaks, among other changes. However, these morphological criteria were replaced by vertebral morphometry, referring to the use of quantitative or quasi-quantitative measurement tools for fracture diagnosis. Vertebral morphometry emerged as an understanding of and treatment for osteoporosis evolved, mainly in response to the need for expeditious assessments of large numbers of spine images for epidemiological and pharmaceutical purposes. Although most of the descriptions of such morphometric tools have stressed that they were not to be applied to clinical diagnosis with respect to individual patients, this constraint has been widely disregarded. Here we review the major attempts to develop a diagnostic strategy for OVF and describe their characteristics in adults and children. Recent evidence suggests that morphometric (quantitative; ie, based on measurement of dimensions and shape description) criteria are inferior to morphologic (qualitative; ie, based on structural integrity) vertebral damage assessment in identifying people with low bone density and at an increased risk of future fracture. Thus there is now an evidentiary basis for suggesting that morphological assessment is the preferred strategy for use in diagnosing OVF from radiographs. © 2019 American Society for Bone and Mineral Research.

Dimensions of the spinous process and interspinous space: a morphometric study

PURPOSE

To measure the morphological dimensions of the spinous process (SP) and interspinous space, and provide a basis for the development of interspinous devices for the Korean or East Asian populations.

METHODS

We retrospectively analyzed the anatomical parameters of 120 patients. The parameters included height, length, and width of SP, interspinous distance (supine, standing, and dynamic), cortical thickness of SP, and spino-laminar (S-L) angle. Correlations between measurements, age, and gender were investigated.

RESULTS

The largest height, length, and cortical thickness and S-L angle were noted at L3. The largest width was observed at S1. The interspinous distance decreased significantly from L2-3 to L5-S1 and was significantly larger in the supine than in standing posture for L5-S1. Cortical thickness was gradually tapered from the anterior to the posterior position. The S-L angle at L2 and L3 was similar and significantly decreased from L3 to S1. An increased trend in width with aging and a decreased trend in distance (supine) were noted. A significant increase in height, length, and distance in males compared with females was also observed.

CONCLUSIONS

The interspinous space is wider at the anterior, and the cortex is thicker anteriorly. Accordingly, it appears that the optimized implant position lies in the interspinous space anteriorly. The varying interspinous space with different postures and gradually narrowing with age suggest the need for caution when sizing the device. Gender differences also need to be considered when designing implantable devices.

Vertebral heights and ratios are not only race-specific, but also gender- and region-specific: establishment of reference values for mainland Chinese

This study established gender-specific reference values in mainland Chinese (MC) and is important for quantitative morphometry for diagnosis and epidemiological study of osteoporotic vertebral compressive fracture. Comparisons of reference values among different racial populations are then performed to demonstrate the MC-specific characteristic.

PURPOSE

Osteoporotic vertebral compressive fracture (OVCF) is a common complication of osteoporosis in the elder population. Clinical diagnosis and epidemiological study of OVCF often employ quantitative morphometry, which relies heavily on the comparison of patients' vertebral parameters to existing reference values derived from the normal population. Thus, reference values are crucial in clinical diagnosis. To our knowledge, this is the first study to establish reference values of the mainland Chinese (MC) for quantitative morphometry.

METHODS

Vertebral heights including anterior (Ha), middle (Hm), posterior (Hp) heights, and predicted posterior height (pp) from T4 to L5 were obtained; and ratios of Ha/Hp, Hm/Hp and Hp/pp. were calculated from 585 MC (both female and male) for establishing reference values and subsequent comparisons with other studies.

RESULTS

Vertebral heights increased progressively from T4 to L3 but then decreased in L4 and L5. Both genders showed similar ratios of vertebral dimensions, but male vertebrae were statistically larger than those of female (P < 0.01). Vertebral size of MC population was smaller than that of US and UK population, but was surprisingly larger than that of Hong Kong Chinese, although these two are commonly considered as one race. Data from different racial populations showed similar dimensional ratios in all vertebrae.

CONCLUSIONS

We established gender-specific reference values for MC. Our results also indicated the necessity of establishing reference values that are not only race- and gender-specific, but also population- or region-specific for accurate quantitative morphometric assessment of OVCF.

Reference Values for Vertebral Heights in Scandinavian Females and Males

Vertebral heights were measured on lateral spine radiographs covering T4—L5 in 113 healthy Caucasian volunteers (73 females aged 22–80 years, and 40 males aged 22–79 years). Vertebral heights were significantly higher in men than in women (p < 0.001). In women, a significant correlation was found between the height of T4 and the heights of the other vertebrae with correlation coefficients ranging from 0.71 (T5) to 0.38 (L1) and similar figures were found in males. Both the absolute and relative vertebral heights in this series were close to those reported by others. Selection of subjects and racial, environmental, and technical factors may explain the small differences. It is concluded that vertebral heights can be predicted from vertebrae rarely affected by spinal osteoporosis. Both relative and absolute vertebral heights differed between sexes. Although the reference values in this Scandinavian population were in agreement with previously reported data, small differences between populations were found, emphasizing the need for regional normative data.

Prevalence of vertebral fracture in Asian men and women: comparison between Hong Kong, Thailand, Indonesia and Japan

OBJECTIVES

Little is known about the prevalence of vertebral fracture among Asians. This study investigated the prevalence of radiographically defined vertebral fracture, and identified associated risk factors in the aged population of four Asian countries.

STUDY DESIGN

In total, 1588 males and females aged ≥ 65 years were recruited from Hong Kong, Thailand, Indonesia and Japan.

METHODS

Standard X-rays for the spine were taken and vertebral heights were measured. Vertebral fracture was defined as a reduction of >3 standard deviations in vertebral height ratio. Bone mineral density (BMD) of the hip was measured by dual energy X-ray absorptiometry, and anthropometric measurements were taken in Hong Kong and Japan. Other relevant data were entered in a standard questionnaire.

RESULTS

The prevalence of vertebral fracture for both males and females was highest in Japan for younger (65-74 years) and older (≥ 75 years) age groups (36.6% and 37.6% for males; 18.8% and 28.7% for females). Lower hip BMD was associated with vertebral fracture in both sexes. Older age, lower quality of life score on Short Form-12 (physical), past longest occupation as a farmer, and history of cataract were significantly associated with vertebral fracture in females. However, smoking did not appear to be an important risk factor for vertebral fracture.

CONCLUSIONS

Radiographic assessments for vertebral fracture were performed in all four Asian countries. The prevalence of vertebral fracture was highest in Japan. Lower hip BMD, poorer physical condition and past longest occupation as a farmer were associated with vertebral fracture.

Reference values for vertebral shape in young Chinese women: implication for assessment of vertebral deformity

The race- and sex-specific reference values for vertebral shape are important to determine the prevalence of osteoporotic vertebral fracture. However, these reference values are absent in Chinese women. In the present study, the anterior, middle and posterior heights and the ratios of these heights were measured from 14 vertebral bodies (T4-L5) in 60 premenopausal Chinese women (aged 19-25 years). Cutoff values were set as standard deviations (3 and 3.5 SD) and percentages (15 and 20%) below the means of vertebral height (VH) ratios to define vertebral deformities. The number of subjects with a VH ratio lower than -15% cutoff were significantly more than those with a VH ratio lower than -3 SD cutoff (p < 0.05), but this difference did not occur when a -20% cutoff was selected. A few VH ratios were distributed below -20% and -3 SD cutoffs, and none was below -3.5 SD. The vertebral shape defined by VH ratios was different between Chinese and European women. We conclude that 3.5 SD below the reference mean is an ideal cutoff value for the definition of prevalent vertebral fractures in Chinese women, and reference data should be obtained from young premenopausal women.

Human osseous intervertebral foramen width

Alterations of the width of the human intervertebral foramen can play a pathophysiological role in low back pain. Osseous dimensions of the human intervertebral foramen are rarely recorded. Therefore, we present reference data obtained from skeletal samples of known lifestyle, population affinity, sex, and age at death. Cervical, thoracic, and lumbar vertebrae of functional transition zones of 71 macroscopically normal spines from early 19th century AD Swiss burial sites were selected. The intervertebral foramen widths (IFW) were analyzed with respect to possible lateralization and the impact of sex, individual age, and stature. Neither a significant side difference nor a correlation of IFW with individual age or stature could be found. Females show somewhat larger IFW than males, especially in the lumbar region. Data comparisons with earlier studies are limited due to methodological differences and possible interpopulational variations. Furthermore, the osseous intervertebral foramen only reveals a glimpse of the clinically relevant in vivo structure. Nevertheless, more focus on the osseous dimensions of the intervertebral foramen will provide baseline data of this important anatomical landmark. These data could also explore the peculiarities of the intervertebral foramen, such as its reverse sex dimorphism.

Vertebral morphometry reference data by X-ray absorptiometry (MXA) in Iranian women

The anterior, medial, and posterior heights and the A/P and M/P ratios of the spine (T5-L4) in 41 normal premenopausal Iranian women were determined using an imaging densitometer (Expert XL) and dual energy X-ray absorptiometry (DXA) method. All the women were healthy (age 20-39 years, and height 149-171 cm), without any signs of vertebral fractures, and with normal bone mineral density (BMD) of the spine and femoral neck (T-score>-1.5). The vertebral heights were normalized using the Expert XL software, and the average vertebral height for the L2-L4 vertebrae was taken to minimize the effect of variation of body size among the subjects. The Z-score for all vertebral heights (T5-L4) averaged -0.68, with the A/P and M/P ratios coming to +0.34 and +0.49, respectively. It showed the normalization procedure not to correct the differences of vertebral heights in Iranian women. The average of the three heights (H (avg)) correlated fairly well with the stature of the subject (r=0.47, p<0.05), but no correlation was found between H (avg) and subject age (p>0.05). The lower vertebral heights in older women in comparison with the younger women (0.4 mm) obtained in our study can be attributed to the relatively shorter stature of older women (mean 154 vs 159 cm for younger women, p<0.05). It was concluded that the normalization procedure used in the software does not equally apply to Iranian women due to their having different heights than those of American and northern European women, from whom the reference data for the Expert XL software have been gathered. The reference values thus obtained are therefore not accurate for our population group and a separate study with a bigger and more varied sample group is needed for obtaining more definitive results.

Local 3D scaling properties for the analysis of trabecular bone extracted from high-resolution magnetic resonance imaging of human trabecular bone: comparison with bone mineral density in the prediction of biomechanical strength in vitro

RATIONALE AND OBJECTIVES

A novel, nonlinear morphologic measure [DeltaP(alpha)] based on local 3D scaling properties was applied to high-resolution magnetic resonance images (HR-MRI) of human trabecular bone to predict biomechanical strength in vitro.

METHODS

We extracted DeltaP(alpha) and traditional morphologic parameters (apparent trabecular volume fraction, apparent trabecular separation) from HR-MR images of 32 femoral and 13 spinal bone specimens. Furthermore, bone mineral density (BMD) and maximum compressive strength (MCS) were determined. The morphologic measures were compared with BMD in predicting the biomechanical strength.

RESULTS

In the vertebral (femoral) specimens, R2 for MCS versus DeltaP(alpha) was 0.87 (0.61) (P < 0.001). Correlation between BMD and MCS was 0.53 (P = 0.05) (0.79 [P < 0.001]) for the vertebral (femoral) specimens. For the femoral specimens, prediction of MCS could be improved further by combining BMD and morphologic parameters by multiple regression (R2 = 0.88).

CONCLUSIONS

Morphologic measures extracted from HR-MRI considering local 3D-scaling properties can be used to predict biomechanical properties of bone in vitro. They are superior to 2-dimensional standard linear morphometric measures and, depending on the anatomic location, more reliably predict bone strength as measured by MCS than does BMD.

Similar prevalence of vertebral fractures despite different approaches to define reference data

Morphometric detection of vertebral fractures requires the use of reference normal values. In previous studies, normal values were obtained in young healthy adults or in adults of various ages in whom abnormal radiographs were excluded using trimming algorithms. We established four sets of normal values defined according to different approaches. We used a group of 102 young healthy women with normal spine radiographs and a population-based cohort of 260 women 51 to 85 years old (EVOS study) to select those with normal spine radiographs based on the semiquantitative method of Genant, the trimming algorithm defined by Melton, and the trimming algorithm defined by Black. Using the four sets of reference data, we applied two diagnostic criteria, the mean - 3SD and the 0.85 x mean to detect prevalent vertebral fractures in two groups of women: the population-based cohort of 260 women recruited for the EVOS study and 176 osteoporotic women 54 to 88 years old with at least one vertebral fracture. In the population-based cohort, the number of vertebral fractures varied from 53 to 57 for the 0.85 x mean cutoff and from 93 to 115 for the mean - 3SD cutoff. In the osteoporotic women, the number of vertebral fractures varied from 255 to 273 for the 0.85 x mean cutoff and from 372 to 404 for the mean - 3SD cutoff. In both groups, the number of vertebral fractures detected with the 0.85 x mean cutoff was close to the number detected by the semiquantitative method of Genant, which does not require a reference population. For the 0.85 x mean cutoff, agreement of diagnosis using different reference values was excellent (kappa = 0.96-0.99). For the mean - 3SD cutoff, agreement of vertebral fracture detection based on the four reference sets was good (kappa = 0.79-0.93). Agreement of diagnosis was lower when two cutoffs were compared using the same set of reference values (kappa = 0.60-0.81). In conclusion, reference data derived using different approaches give similar rates of prevalence of vertebral fractures. Compared to the semiquantitative assessment, the prevalence of vertebral fractures is similar for the 0.85 x mean cutoff, whereas it is considerably higher for the mean - 3SD cutoff.

Assessment of prevalent and incident vertebral fractures in osteoporosis research

Vertebral fractures are the hallmark of osteoporosis, and it has been shown that the presence of vertebral fractures adds to the risk of future osteoporotic fractures. Thus, the evaluation of spinal radiographs for prevalent or incident vertebral fractures is important in the clinical evaluation of patients with osteoporosis, in clinical drug trials for osteoporosis treatment and in the epidemiologic evaluation of populations at risk for osteoporosis. Traditionally, conventional lateral radiographs of the thoracolumbar spine have been analyzed visually by radiologists or experienced clinicians to identify vertebral fractures in patients with clinical indications. Epidemiologic studies or clinical drug trials in osteoporosis research have considerably different requirements and expectations. To reduce potential subjectivity in qualitative readings and to provide definable, reproducible and objective methods to detect vertebral fracture, and to accommodate the assessment of large numbers of radiographs, various morphometric approaches have been explored and employed. However, potential deficiencies in morphometry have led to a renewed interest in standardized qualitative visual approaches for defining vertebral fractures and visual criteria. Numerous studies have shown that semiquantitative interpretation, after careful centralized training and standardization, can produce results with excellent intra- and interobserver reproducibility. We firmly believe that the experience from several studies has shown that there is a major role for radiologists and clinicians alike to carefully assess and diagnose vertebral fractures using standardized grading schemes such as the one proposed in this review. In the context of epidemiologic studies and clinical drug trials, quantitative morphometry may be used; however, the studies would be flawed if quantitative morphometry were to be performed in isolation without additional adjudication by a trained and highly experienced radiologist or clinician.

Intervertebral disc disorganisation and its relationship to age adjusted vertebral body morphometry and vertebral bone architecture

Vertebral deformity, intervertebral disc disorganisation, and change to vertebral bone architecture are morphological features that are associated with low back pain. The purpose of this study was to examine the influence of the morphological disorganisation of the intervertebral disc on vertebral body shape indices and vertebral cancellous bone architecture. Lumbar spines, T12-S1, were collected from 27 cadavers. The motion segments T12-L1, L2-L3 and L4-L5 were selected for the study. There were 8 females aged 35-94 years and 19 males aged 20-90 years. An intervertebral disc grade signifying the severity of disc disorganisation was assigned to each disc using the macroscopic disc grading criteria of Hansson and Roos (Spine, 1981; 6:147-153.). Vertebral shape indices and vertebral body bone histomorphometric analyses were performed on the vertebral bodies. Where appropriate, data were age adjusted and the influence of morphological disc disorganisation on vertebral body deformity and cancellous bone architecture analysed. Increased vertebral body axial area and the ratio of vertebral body axial area to sagittal area were associated with an increase in vertebral deformity and disc disorganisation. This suggests that vertebral deformity that remains clinically silent in the general population is influenced by intervertebral disc disorganisation. Vertebral cancellous bone architecture undergoes change associated with increased disc disorganisation, consistent with increased vertebral deformity. Vertebral bodies adjacent to degenerate discs (Grade 4) showed increased BV/TV and Tb.Th and decreased BS/BV. This shows that disc disorganisation may modulate vertebral cancellous bone architecture such that it protects against age-related bone changes. In addition, vertebral body wedging and concavity are associated with smaller vertebral body size and vertebral body compression is associated with larger vertebral body size and compromised cancellous bone architecture.

Comparison of morphometric assessment of prevalent vertebral deformities in women using different reference data

The semiquantitative assessment of vertebral deformities is based on visual evaluation. The quantitative approach is based on different morphometric criteria. This study is aimed at comparing the impact of different reference groups to define normal vertebral shape on the diagnosis of verterbral deformities. Reference normal values were obtained in three groups of women: French, mixed European, and Argentinian. All these women had normal lumbar spine bone mineral density and no vertebral deformities according to the semiquantitative assessment. In a group of 135 women having vertebral deformities according to Genant's semiquantitative assessment, three different morphometric criteria were applied. Morphometric diagnosis disclosed a good agreement with semiquantitative assessment. Agreement of diagnosis was higher for a given cutoff using thresholds obtained in different reference groups (kappa = 0.84-0.96) and lower when different criteria were compared using thresholds obtained in the same reference group (kappa = 0. 75-0.85). When fracture thresholds obtained in three different cohorts were compared separately for the three morphometric criteria, agreement was the highest when the cutoff was based only on the arithmetical mean of vertebral heights and was independent of its standard deviation (SD). Average vertebral height ratios did not differ between the three reference cohorts, whereas SDs of vertebral height ratios were the highest in the mixed European cohort and the lowest in the French cohort (F = 7.41, p < 0.001). In the three groups of women of different nationality, SDs of vertebral height ratios, but not the arithmetical means, were significantly higher in the radiographs of poor quality compared with those of good quality. Thus, the main source of difference of diagnosis was related to different SDs whereas average height ratios were not different. Differences in SDs between the three groups were found to be related, at least partly, to poor quality of radiographs. The impact of the differences between populations seems less important, however, only three countries were compared. These findings suggest that those techniques that take into account the SD of vertebral height ratios will provide different reference values for vertebral morphometry. Because differences in SDs depend mainly on the quality of radiographs, they can be reduced by improving the X-ray technique and by the use of standardized protocols. This variability will result in the identification of a variable number of vertebral deformities in osteoporotic women. These results may be of importance especially for multicentric studies.

Geometric measurements of the lumbar spine in Chinese men during trunk flexion

STUDY DESIGN

An analysis of the geometric data of the lumbar spine in Chinese men. Lateral radiographs were obtained of 16 men in the upright position to a trunk flexion of 90 degrees in 30 degrees increments.

OBJECTIVES

To establish reference data concerning the geometry of the lumbar spine for various degrees of trunk flexion.

SUMMARY OF BACKGROUND DATA

In previous studies, the morphometry and alignment of the lumbar spine have been investigated. Reports of systematic analyses of the lumbar spine in trunk flexion have lacked adequate radiographic data. Moreover, few studies have focused on measuring lumbar spine geometric data in Chinese individuals.

METHODS

A total of 67 landmarks on each radiograph were identified. They were marked by investigators and digitized using a HyperSpace digitizing system (V.17: Mira Imaging Inc., Salt Lake City, UT). The geometric configuration of the vertebrae and discs then was derived from the digitized points.

RESULTS

The dimensions of the vertebrae and disc on the lumbar spine obtained in this study were similar to those of previous studies. The motion of the lumbosacral spine had the greatest contribution in trunk flexion, approximately 90% (i.e., rotating at the rate of 9 degrees for each 10 degrees of trunk flexion) when the trunk was flexed from 30 degrees to 60 degrees. After that, the hips were dominant in accomplishing the trunk flexion from 60 degrees to horizontal. This motion patterns may be useful for making clinical diagnoses of lumbar function in Chinese men.

CONCLUSIONS

No obvious interracial differences were found in the geometric data found in this study, which suggests that morphometric data obtained from Caucasian individuals may be applied to Chinese patients for clinical purposes.

Morphometric X-ray absorptiometry: reference data for vertebral dimensions

Vertebral fractures are a common and important consequence of osteoporosis and are often identified via morphometric analysis of conventional lateral spine radiographs (morphometric radiography or MRX). A new method of performing vertebral morphometry using images acquired on dual-energy X-ray absorptiometry (DXA) scanners (morphometric X-ray absorptiometry or MXA) has recently been developed. In this study, we derive reference data for vertebral heights and height ratios using MXA scans as the data source and compare the results with previously published MRX studies. One thousand and nineteen Caucasian women (mean age 63 years, range 33-86) were recruited. An MXA scan, covering 13 vertebrae from L4 to T4, was acquired for each subject on one of four DXA systems located at three centers in the U.K. Analysis of variance found statistically significant but relatively small differences among centers, machines, and scan modes, and therefore data were pooled for reference range calculations. Three vertebral heights (anterior, mid, and posterior) were measured and four ratios (wedge, mid-wedge, and two crush) calculated. These data sets were trimmed using an iterative algorithm to remove extreme values assumed to represent deformed vertebrae, then mean and SD values were calculated using the remaining data. When the data were split by age, a small but statistically significant decrease in vertebral height between the sixth and eighth decades was found, but this was not replicated for the vertebral height ratios. Marked differences were observed between MXA data and MRX, but were comparable to those between different MRX studies. These may result from differences in image quality and point placement protocols, population differences, differences in radiographic technique, and differences in the derivation of a group of "normal" vertebrae. This study suggests that reference data of vertebral dimensions should be specific to the technique which uses those data as a reference, i.e., MXA.

Epidemiology of spinal osteoporosis

Approximately 30% of postmenopausal white women in the United States have osteoporosis, and 16% have osteoporosis of the lumbar spine in particular. Bone density of the spine is positively associated with greater height and weight, older age at menopause, a history of arthritis, more physical activity, moderate use of alcoholic beverages, diuretic treatment, and current estrogen replacement therapy, whereas later age at menarche and a maternal history of fracture are associated with lower levels of density. Low bone density leads to an increased risk of osteoporotic fractures. Fracture risk also increase with age. Vertebral fractures affect approximately 25% of postmenopausal women, although the exact figure depends on the definition used. Recent data show that vertebral fracture rates are as great in men as in women but, because women live longer, the lifetime risk of a vertebral fracture from age 50 onward is 16% in white women and only 5% in white men. Fracture rates are less in most nonwhite populations, but vertebral fractures are as common in Asian women as in those of European heritage. Other risk factors for vertebral fractures are less clear but include hypogonadism and secondary osteoporosis; obesity is protective of fractures as it is of bone loss. Compared with hip fractures, vertebral fractures are less disabling and less expensive, costing approximately $746 million in the United States in 1995. However, they have a substantial negative impact on the patient's function and quality of life. The adverse effects of osteoporotic fractures are likely to increase in the future with the growing number of elderly people.

Normal ranges for vertebral height ratios and prevalence of vertebral fracture in Hong Kong Chinese: a comparison with American Caucasians

We have established the normal ranges for vertebral height ratios and studied the prevalence of vertebral fracture in 481 Chinese women aged 70-79. Our results were compared with those of an American study with a similar methodology. Lateral spine radiographs centered at T8 and L3 were taken, and the anterior, middle, and posterior vertebral heights of each vertebra from T5 to L4 were measured. The means and standard deviations (SDs) of the anterior to posterior, middle to posterior, and posterior to posterior vertebral height ratios were derived after trimming the extreme values from the distribution. The Chinese had smaller vertebral size than the American Caucasians at all levels. Moreover, the anterior to posterior vertebral height ratios were consistently smaller in the Chinese than in the Americans from T10 onward. The means of other vertebral height ratios in the Chinese were similar to the American Caucasians, but the SDs were greater in the Chinese. The prevalence of vertebral fracture was 29% in the Chinese and 25% in the American Caucasians if a cut-off of 3 SD below the mean for vertebral height ratios was used. We conclude that population-specific means and SD should be used for defining vertebral fracture and that the prevalence of vertebral fracture is similar in Hong Kong Chinese and American Caucasians.

Factors contributing to skeletal health of postmenopausal Mexican-American women

Incidence rates of hip fracture are lower in Hispanic (HC) than non-Hispanic Caucasians (NHC). To investigate factors that may affect skeletal health of Hispanics, we recruited 152 healthy community-dwelling Mexican-American Caucasian women into a 4-year longitudinal study that evaluates bone mass, nutritional status, muscle strength, mobility, falls, and other factors that may contribute to fracture risk. Results from the baseline component of the study are reported herein. Average bone mineral densities (BMD) evaluated by dual-energy X-ray absorptiometry (DXA) in this study group did not differ from BMDs in healthy, NHC women of similar age. Hip axis length (HAL), however, was significantly shorter than that reported for nonosteoporotic NHC. Factors independently associated with greater BMD and BMC at certain skeletal sites were lean body mass, fat mass, acculturation, years of estrogen use, sun exposure, hip adductor strength, grip strength, erythrocyte folate, and serum glucose concentrations. Factors independently associated with lower BMD and BMC at certain skeletal sites were age, parity, and vertebral deformities (all p < 0.05). Thus, the decreased risk of hip fracture in HC compared with NHC does not appear to be due to high bone mass. However, other factors such as HAL and body composition may play a role in maintenance of skeletal integrity.

Variation in vertebral height ratios in population studies. European Vertebral Osteoporosis Study Group

Vertebral height ratios are used to define vertebral deformity in clinical and epidemiologic studies of vertebral osteoporosis. However, few data have been obtained on the variation in these ratios in different populations using standard methods. We examined vertebral morphometric measurements obtained in a population survey from three centers: Malmö (Sweden), Montceau-les-Mines (France), and Graz (Austria), to study the influence of sex and the population center on vertebral height ratios. Radiographs were obtained according to a standardized protocol, and morphometric measurements, anterior height Ha, central height Hc, and posterior height Hp, made in Berlin. The height ratios anterior, Ha/Hp, central, Hc/Hp, posterior I, Hp/Hp', and posterior II, Hp/Hp" (Hp' = posterior height of vertebrae above, Hp" = posterior height of vertebrae below) were calculated for each vertebra from T4 to L4. The mean and standard deviation of these ratios for each sex and each center were derived using a statistical trimming procedure to normalize the distribution. Threshold values for defining grade 1 and grade 2 deformities, wedge, biconcavity, and compression, were calculated using these parameters. Anterior and central vertebral height ratios were smaller in males than females (p < 0.01). There were significant differences between the three centers (p < 0.01) both in the trimmed mean values for anterior and central vertebral height ratios and in the thresholds derived using standard criteria for defining wedge and biconcavity deformity. The data confirm the impression from single-center studies that vertebral height ratios vary between populations and suggest that reference values for vertebral height ratios should be derived separately for males and females within individual populations whenever possible.

Effects of calcium supplements on femoral bone mineral density and vertebral fracture rate in vitamin-D-replete elderly patients

The efficacy of calcium (Ca) in reducing bone loss is debated. In a randomized placebo-controlled double-masked study, we investigated the effects of oral Ca supplements on femoral shaft (FS), femoral neck (FN) and lumbar spine (LS) bone mineral density (BMD), and on the incidence of vertebral fracture in vitamin-D-replete elderly. Ninety-three healthy subjects (72.1 +/- 0.6 years) were randomly allocated to three groups receiving 800 mg/day Ca in two different forms or a placebo for 18 months. Sixty-three patients (78.4 +/- 1.0 years) with a recent hip fracture were allocated to two groups receiving the two forms of Ca without placebo. FS BMD changes in Ca-supplemented non-fractured women were significantly different from those in the placebo group (+0.6 +/- 0.5% v -1.2 +/- 0.7%, p < 0.05). There was no difference in effect between the two forms of Ca. The changes of +0.7 +/- 0.8% v -1.7 +/- 1.6% in FN BMD of Ca-supplemented women and the placebo group did not reach statistical significance. In fractured patients, FS, FN and LS BMD changes were -1.3 +/- 0.8, +0.3 +/- 1.6 and +3.1 +/- 1.2% (p < 0.05 for the last). The rate of new vertebral fractures was 74.3 and 106.2 fractures per 1000 patient-years in Ca-supplemented non-fractured subjects and in the placebo group, respectively, and 144.0 in Ca-supplemented fractured patients. Thus, oral Ca supplements prevented a femoral BMD decrease and lowered vertebral fracture rate in the elderly.

Spine fracture risk is predicted by non-spine fractures

A prospective cohort study of 1098 postmenopausal Japanese-American women evaluated the relationship between baseline non-spine fractures and new (incident) spine fractures. At the baseline examination in 1981, prevalent non-spine fractures were ascertained by interview, and prevalent spine fractures by radiograph. Bone mass measurements of the distal radius, proximal radius, calcaneus (1981), the lumbar spine (1984) were obtained and repeated at 1- to 2-year intervals. Women with existing non-spine fractures have a threefold greater risk of subsequent spine fractures, independent of bone mass, and independent of the known association between prevalent spine fractures and subsequent spine fractures. Women with both a prevalent non-spine fracture and low bone mass (50th percentile or lower) have an eightfold greater risk of new spine fractures compared with women above the 50th percentile of bone mass and no prevalent fractures. In addition to low bone mass, both prevalent spine fractures and prevalent non-spine fractures are strong risk factors for subsequent spine fracture. These data suggest that not all osteoporotic risk factors are expressed via bone mass, and that other, unmeasured risk factors, such as bone quality defects, may explain these results. In clinical terms, women with both prevalent fractures and low bone mass should be recognized as being at extremely high risk, and treatment potency should be commensurate with this level of risk.

Quantification of overload injuries to thoracolumbar vertebrae and discs in persons exposed to heavy physical exertions or vibration at the work-place The shape of vertebrae and intervertebral discs - study of a young, healthy population and a middle-aged control group

The ongoing search for causes (and strategies for prevention) of low back trouble in sub-groups of the population exposed to heavy physical exertions or whole body vibration requires reliable data on the prevalence of lower-spine overload damage. Because published reports on this topic are rare and mostly qualitative, the present study was initiated to assess, objectively and quantitatively, overload damage to vertebrae and intervertebral discs. Part I of the work has involved the establishment of a normative database of shape parameters from measurements of 683 (539 male, 144 female) lateral radiographic views of the thoracolumbar spine of young (17-30 years), healthy subjects. In addition, age-related shape alterations were explored from measurements of 364 male middle-aged (31-57 years), non-exposed controls. Advanced methods for shape analysis and shape parameter construction were required, and duly developed, in order to minimise the influence of confounding factors such as radiographic magnification, image distortion, axial rotation or lateral tilt. The results revealed that the variation in shape parameters varies between 2% and 10% within the group of normals (this being largely biological variability as opposed to measurement error). Within this normal group subtle but statistically significant differences due to gender and geographic origin were observed. Comparison of the normals with the controls revealed only slight, but clearly demonstrable differences. The narrow range of 'normal shape' together with the high accuracy of shape analysis are the foundation for Part II of this study which will involve a comparison of exposed cohorts with the normal standard (adjusted for ageing effects). This will, for the first time, enable objective quantification of the prevalence of overload damage to the spines of persons exposed to heavy physical stresses and whole body vibration, and thus form the basis of a scientific rationale for recommendation of safety guidelines.

A new method for vertebral fracture diagnosis

A number of methods have been proposed for estimating the prevalence of vertebral fractures. Most methods are based on the distribution of normal vertebral dimensions in the population. However, these methods fail to identify a significant proportion (20-30% or more) of fractures documented on serial radiographs. This may occur because vertebral size varies between individuals as a result of differences in body size (and possibly other factors), and a normal range based on population reference data may be too large. In this paper, a new method is described for identifying vertebral fractures that are missed using diagnostic criteria based on vertebral dimension distributions of the population. This new method is based on calculating the average vertebral size, and statistical confidence limits, for the individual. The average vertebral size method was evaluated by testing its ability to identify incident fractures (which were identified from changes in dimensions compared to previous radiographs), using only the final film. The new method correctly identified most (81% of crush and 83% of wedge) incident fractures on the final radiograph. In contrast, criteria based on population distributions correctly identified only 53% of crush and 72% of wedge incident fractures. Using prospective data, prevalent fractures identified using both population-based and individual size-based criteria predicted the risk of incident fractures. Furthermore, incident fractures identified using both methods (population- and individual-based criteria) were associated with increased back pain. These data suggest that both types of prevalent deformities are important indicators of disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Ability of vertebral dimensions from a single radiograph to identify fractures

It has been proposed that vertebral dimensions be used to objectively identify vertebral fractures, permitting standardization of methodology for comparisons between studies. In this report, we evaluate the ability of various vertebral dimensions and ratios to identify "abnormal" vertebrae. As no "gold standard" exists for prevalent vertebral fractures, we examined the ability of cross-sectional dimensions (at a single point in time) to detect fractured vertebrae that had been identified from changes in dimensions compared with previous radiographs. Theoretically, a cutoff of 3 SD below the mean will rarely misclassify normal vertebrae as fractured (specificity = 99.9%). However, we found that this cutoff correctly identified only about 70% of the incident fractures. A less stringent criterion (2 SD below the mean; theoretical specificity = 97.7%) identified about 85-90% of true fractures. Dividing by stature or other vertebral heights sometimes yielded marginal improvements in the ability of the anterior or posterior height dimensions to diagnose fractures. The results suggest that the true fracture prevalence may sometimes be substantially higher than suggested by cross-sectional vertebral measurements.