Age-related trends in vertebral dimensions

Morphometric analysis of sacral corridor in the upper three sacral segments to prevent neurovascular injury

Although studies of the sacral corridor dimension have been reported in the European population, little attention has been paid to this issue in the Asian population. The purpose of the study is to estimate the safe dimension of the corridor to avoid neurovascular damage during the fixation of the sacral fracture. The study aimed to examine the cephalocaudal (vertical) and the anteroposterior diameter of the bony passage in the upper three sacral segments. The study further examines the effect of age and sex on corridor dimensions at different sacral levels. Three-dimensionally reconstructed sacra from computed tomography of normal subjects were included in the study. Cephalocaudal and anteroposterior diameters were measured in coronal and axial sections using Geomagic Freeform Plus software. Anteroposterior diameter of the sacral corridor at the first, second, and third sacral segments are significantly higher in males (P=0.013, 0.0011, and <0.0001, respectively). The length of the sacrum also revealed sexual dimorphism (P<0.00016). The anteroposterior diameter of the second sacral segment (ap-S2c) correlated moderately with the first sacral anteroposterior diameter (ap-S1c) (R=0.519, P<0.001). The ap-S2c exhibited a moderate correlation to the third sacral segment (ap-S3c) (R=0.677, P<0.001). The sacral corridor at the level of S1 has the largest cephalocaudal (18.25 mm) and anteroposterior diameter (17.11 mm). Placement of the screw in the first sacral corridor may avoid damage to the neurovascular bundle during the fixation of the sacral fracture.

Sex differences and age-related changes in vertebral body volume and volumetric bone mineral density at the thoracolumbar spine using opportunistic QCT

Objectives

To quantitatively investigate the age- and sex-related longitudinal changes in trabecular volumetric bone mineral density (vBMD) and vertebral body volume at the thoracolumbar spine in adults.

Methods

We retrospectively included 168 adults (mean age 58.7 ± 9.8 years, 51 women) who received ≥7 MDCT scans over a period of ≥6.5 years (mean follow-up 9.0 ± 2.1 years) for clinical reasons. Level-wise vBMD and vertebral body volume were extracted from 22720 thoracolumbar vertebrae using a convolutional neural network (CNN)-based framework with asynchronous calibration and correction of the contrast media phase. Human readers conducted semiquantitative assessment of fracture status and bony degenerations.

Results

In the 40-60 years age group, women had a significantly higher trabecular vBMD than men at all thoracolumbar levels (p<0.05 to p<0.001). Conversely, men, on average, had larger vertebrae with lower vBMD. This sex difference in vBMD did not persist in the 60-80 years age group. While the lumbar (T12-L5) vBMD slopes in women only showed a non-significant trend of accelerated decline with age, vertebrae T1-11 displayed a distinct pattern, with women demonstrating a significantly accelerated decline compared to men (p<0.01 to p<0.0001). Between baseline and last follow-up examinations, the vertebral body volume slightly increased in women (T1-12: 1.1 ± 1.0 cm3; L1-5: 1.0 ± 1.4 cm3) and men (T1-12: 1.2 ± 1.3 cm3; L1-5: 1.5 ± 1.6 cm3). After excluding vertebrae with bony degenerations, the residual increase was only small in women (T1-12: 0.6 ± 0.6 cm3; L1-5: 0.7 ± 0.7 cm3) and men (T1-12: 0.7 ± 0.6 cm3; L1-5: 1.2 ± 0.8 cm3). In non-degenerated vertebrae, the mean change in volume was <5% of the respective vertebral body volumes.

Conclusion

Sex differences in thoracolumbar vBMD were apparent before menopause, and disappeared after menopause, likely attributable to an accelerated and more profound vBMD decline in women at the thoracic spine. In patients without advanced spine degeneration, the overall volumetric changes in the vertebral body appeared subtle.

Estimating age at death by Hausdorff distance analyses of the fourth lumbar vertebral bodies using 3D postmortem CT images

The existing methods for determining adult age from human skeletons are mostly qualitative. However, a shift in quantifying age-related skeletal morphology on a quantitative scale is emerging. This study describes an intuitive variable extraction technique and quantifies skeletal morphology in continuous data to understand their aging pattern. A total of 200 postmortem CT images from the deceased aged 25-99 years (130 males, 70 females) who underwent forensic death investigations were used in the study. The 3D volume of the fourth lumbar vertebral body was segmented, smoothed, and post-processed using the open-source software ITK-SNAP and MeshLab, respectively. To measure the extent of 3D shape deformity due to aging, the Hausdorff distance (HD) analysis was performed. In our context, the maximum Hausdorff distance (maxHD) was chosen as a metric, which was subsequently studied for its correlation with age at death. A strong statistically significant positive correlation (P < 0.001) between maxHD and age at death was observed in both sexes (Spearman's rho = 0.742, male; Spearman's rho = 0.729, female). In simple linear regression analyses, the regression equations obtained yielded the standard error of estimates of 12.5 years and 13.1 years for males and females, respectively. Our study demonstrated that age-related vertebral morphology could be described using the HD method. Moreover, it encourages further studies with larger sample sizes and on other population backgrounds to validate the methodology.

A novel method to estimate adult age from the lumbar vertebral body using 3D PMCT images in Japanese

This study evaluated the age-related changes in the vertebral body using 3D Postmortem CT (PMCT) images and proposed an alternative age estimation formula. The PMCT images of 200 deceased individuals aged 25 to 99 years (126 males, 74 females) were retrospectively reviewed and included in the study. Using the open-source software ITK-SNAP and MeshLab, a 3D surface mesh of the fourth lumbar vertebral body (L4) and its convex hull models were created from the PMCT data. Using their inbuilt tools, volumes (in mm3) of the L4 surface mesh and convex hull models were subsequently computed. We derived VD, defined as the difference in volumes between the convex hull and L4 surface mesh normalized by L4 mesh volume, and VR, defined as the ratio of L4 mesh volume to convex hull volume based on individual L4. Correlation and regression analyses were performed between VD, VR, and chronological age. A statistically significant positive correlation (P < 0.001) between chronological age and VD, (r_s = 0.764, males; r_s = 0.725, females), and a significant negative correlation between chronological age and VR (r_s = -0.764, males; r_s = -0.725, females) was obtained in both sexes. The lowest standard error of the estimate was demonstrated by the VR at 11.9 years and 12.5 years for males and females, respectively. As such, their regression models to estimate adult age were Age = 248.9-2.5VR years, males; Age = 258.1-2.5VR years, females. These regression equations may be useful for estimating age in Japanese adults in forensic settings.

Statistical multi-level shape models for scalable modeling of multi-organ anatomies

Statistical shape modeling is an indispensable tool in the quantitative analysis of anatomies. Particle-based shape modeling (PSM) is a state-of-the-art approach that enables the learning of population-level shape representation from medical imaging data (e.g., CT, MRI) and the associated 3D models of anatomy generated from them. PSM optimizes the placement of a dense set of landmarks (i.e., correspondence points) on a given shape cohort. PSM supports multi-organ modeling as a particular case of the conventional single-organ framework via a global statistical model, where multi-structure anatomy is considered as a single structure. However, global multi-organ models are not scalable for many organs, induce anatomical inconsistencies, and result in entangled shape statistics where modes of shape variation reflect both within- and between-organ variations. Hence, there is a need for an efficient modeling approach that can capture the inter-organ relations (i.e., pose variations) of the complex anatomy while simultaneously optimizing the morphological changes of each organ and capturing the population-level statistics. This paper leverages the PSM approach and proposes a new approach for correspondence-point optimization of multiple organs that overcomes these limitations. The central idea of multilevel component analysis, is that the shape statistics consists of two mutually orthogonal subspaces: the within-organ subspace and the between-organ subspace. We formulate the correspondence optimization objective using this generative model. We evaluate the proposed method using synthetic shape data and clinical data for articulated joint structures of the spine, foot and ankle, and hip joint.

Increased vertebral body area, disc and facet joint degeneration throughout the lumbar spine in patients with lumbosacral transitional vertebrae

OBJECTIVES

Lumbosacral transitional vertebrae (LSTV), developmental spinal canal stenosis, lumbar disc and facet joint degeneration are all common lumbar spine conditions. This study explores the relationship between these entities.

METHODS

Five hundred and five patients (254 females, 251 males), mean age 57 ± 13 years, who underwent abdominopelvic CT examinations were studied. Vertebral body cross-sectional area (CSA), spinal canal CSA, width and depth were measured from L1 to L5. The presence of LSTV was documented and the severity of disc/facet joint degeneration graded.

RESULTS

LSTV was present in 155 (31%) of 505 patients, being twice as common in males than in females. After controlling for age, height and weight, vertebral body CSAs from L1 to L5 in male LSTV patients were, on average, 9.8% larger than those in male non-LSTV patients (p < 0.0001 for all) while vertebral body areas at L3 and L4 were 4.5% larger in female LSTV patients than in non-LSTV female patients. Disc degeneration from L2/3 to L5/S1 and facet joint degeneration from L2/3 to L4/5 were more severe in LSTV patients. LSTV Castellvi Type II patients appear to be most prone to disc and facet degeneration.

CONCLUSIONS

LSTV patients, and particularly male patients, have an increased vertebral body CSA compared to non-LSTV patients throughout the lumbar spine. LSTV patients also have more severe disc and facet joint degeneration. The increase in vertebral body area may be contributing to the increased lumbar and facet joint degeneration seen in LSTV patients.

KEY POINTS

• LSTV patients have increased vertebral body cross-sectional area throughout their lumbar spine compared to non-LSTV patients. This vertebral body area increase was more pronounced in male patients and also apparent in younger patients with LSTV. • LSTV patients have increased disc and facet joint degeneration affecting most of the lumbar spine than non-LSTV patients. • Increased vertebral body area may contribute to the increased lumbar disc and facet joint degeneration seen in LSTV patients.

Synchronous imaging of pelvic geometry and muscle morphometry: a pilot study of pelvic retroversion using upright MRI

This study investigated feasibility of imaging lumbopelvic musculature and geometry in tandem using upright magnetic resonance imaging (MRI) in asymptomatic adults, and explored the effect of pelvic retroversion on lumbopelvic musculature and geometry. Six asymptomatic volunteers were imaged (0.5 T upright MRI) in 4 postures: standing, standing pelvic retroversion, standing 30° flexion, and supine. Measures included muscle morphometry [cross-sectional area (CSA), circularity, radius, and angle] of the gluteus and iliopsoas, and pelvic geometry [pelvic tilt (PT), pelvic incidence (PI), sacral slope (SS), L3-S1 lumbar lordosis (LL)] L3-coccyx. With four volunteers repeating postures, and three raters assessing repeatability, there was generally good repeatability [ICC(3,1) 0.80-0.97]. Retroversion had level dependent effects on muscle measures, for example gluteus CSA and circularity increased (up to 22%). Retroversion increased PT, decreased SS, and decreased L3-S1 LL, but did not affect PI. Gluteus CSA and circularity also had level-specific correlations with PT, SS, and L3-S1 LL. Overall, upright MRI of the lumbopelvic musculature is feasible with good reproducibility, and the morphometry of the involved muscles significantly changes with posture. This finding has the potential to be used for clinical consideration in designing and performing future studies with greater number of healthy subjects and patients.

The association between physical activity and vertebral dimension change in early adulthood - The Northern Finland Birth Cohort 1986 study

Small vertebral size is a well-known risk factor for vertebral fractures. To help understanding the factors behind vertebral size, we aimed to investigate whether physical activity and participation in high-impact exercise are associated with the growth rate of the vertebral cross-sectional area (CSA) among young adults. To conduct our study, we utilized the Northern Finland Birth Cohort 1986 as our study population (n = 375). Questionnaire data about physical activity was obtained at 16, 18 and 19 years of age and lumbar magnetic resonance imaging scans at two timepoints, 20 and 30 years of age. We used generalized estimating equation (GEE) models to conduct the analyses. We did not find any statistically significant associations between vertebral CSA, physical activity, and high-impact exercise in our study sample. We conclude that neither physical activity nor high-impact sports seem to influence the change in vertebral CSA among young adults.

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Physical activity does not influence the growth rate of the vertebral body.

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High-impact sports are not associated with the change in vertebral CSA among adults.

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The study was conducted using longitudinal MRI data.

How Does Obesity Influence the Risk of Vertebral Fracture? Findings From the UK Biobank Participants

Obesity and osteoporotic‐related fractures are two common public health problems, although it is unclear how obesity affects the risk of vertebral fractures. The purpose of this study was to examine the association between different measures of obesity and the risk of vertebral fracture, and to establish the various clinical factors that can predict such risk. We analyzed data obtained from 502,543 participants in the UK Biobank (229,138 men and 273,405 women), aged 40 to 69 years. Imaging information was available in a subset of this cohort (5189 participants: 2473 men and 2716 women). We further examined how BMD and geometry of the vertebrae were related to body fat measures. It was shown that a larger waist circumference (WC), but not BMI, was associated with an increase in fracture risk in men, but in women, neither BMI nor WC affected the risk. Trunk fat mass, visceral adipose tissue (VAT) mass, and limb fat mass were negatively associated with vertebral body BMD and geometry in men and women. BMD and geometry are related to vertebral strength, but may not be directly related to the risk of fractures, which is also influenced by other factors. The binary logistic regression equation established in this study may be useful to clinicians for the prediction of vertebral fracture risks, and may provide further information to supplement the fracture risk assessment tool, which assesses general fracture risks. © 2020 The Authors. JBMR Plus published by Wiley Periodicals, Inc. on behalf of American Society for Bone and Mineral Research.

Temporal Trends in Vertebral Dimensions - a case study from Finland

Vertebral fractures and other back problems represent a major, increasing worldwide health problem. This has increased the need to better understand the reasons behind this phenomenon. In addition to a reduction in bone mineral density and overall size of the vertebral body, research has indicated a possible association between the shape of the endplate and spinal disorders. As one previous study has shown changes in vertebral body dimensions between contemporary people and their medieval counterparts, we wanted to examine the potential temporal trends in vertebral size and dimensions in Finnish samples of archaeological and contemporary individuals. To conduct this study, we utilized three archaeological populations from the 16^th–19^th century and clinical materials from two population-based Finnish birth cohorts. As the average height of people has increased greatly since the first time period, we also height-adjusted the dimensions to provide a clearer picture of the dimensional changes that have occurred in the later temporal group. Our results were in agreement with those of the earlier study. The archaeological samples had a larger vertebral size than the contemporary population when height was adjusted for. Vertebral mediolateral width in particular had decreased, and the shape of the vertebral body had changed.

Body mass estimation from dimensions of the fourth lumbar vertebra in middle-aged Finns

Although body mass is not a stable trait over the lifespan, information regarding body size assists the forensic identification of unknown individuals. In this study, we aimed to study the potential of using the fourth lumbar vertebra (L4) for body mass estimation among contemporary Finns. Our sample comprised 1158 individuals from the Northern Finland Birth Cohort 1966 who had undergone measurements of body mass at age 31 and 46 and lumbar magnetic resonance imaging (MRI) at age 46. MRI scans were used to measure the maximum and minimum widths, depths, and heights of the L4 body. Their means and sum were calculated together with vertebral cross-sectional area (CSA) and volume. Ordinary least squares (OLS) and reduced major axis (RMA) regression was used to produce equations for body mass among the full sample (n = 1158) and among normal-weight individuals (n = 420). In our data, body mass was associated with all the L4 size parameters (R = 0.093-0.582, p ≤ 0.019 among the full sample; R = 0.243-0.696, p ≤ 0.002 among the normal-weight sample). RMA regression models seemed to fit the data better than OLS, with vertebral CSA having the highest predictive value in body mass estimation. In the full sample, the lowest standard errors were 6.1% (95% prediction interval ±9.6 kg) and 7.1% (±9.1 kg) among men and women, respectively. In the normal-weight sample, the lowest errors were 4.9% (±6.9 kg) and 4.7% (±5.7 kg) among men and women, respectively. Our results indicate that L4 dimensions are potentially useful in body mass estimation, especially in cases with only the axial skeleton available.

Dairy- and supplement-based calcium intake in adulthood and vertebral dimensions in midlife-the Northern Finland Birth Cohort 1966 Study

Among a representative sample of 1064 Northern Finns, we studied the association of dairy- and supplement-based calcium intake in adulthood with vertebral size in midlife. Inadequate calcium intake (< 800 mg/day) from age 31 to 46 predicted small vertebral size and thus decreased spinal resilience among women but not men.

INTRODUCTION

Small vertebral size predisposes individuals to fractures, which are common among aging populations. Although previous studies have associated calcium (Ca) intake with enhanced bone geometry in the appendicular skeleton, few reports have addressed the axial skeleton or the vertebrae in particular. We aimed to investigate the association of dairy- and supplement-based Ca intake in adulthood with vertebral cross-sectional area (CSA) in midlife.

METHODS

A sample of 1064 individuals from the Northern Finland Birth Cohort 1966 had undergone lumbar magnetic resonance imaging at the age of 46, and provided self-reported data on diet and Ca intake (dairy consumption and use of Ca supplements) at the ages of 31 and 46. We assessed the association between Ca intake (both continuous and categorized according to local recommended daily intake) and vertebral CSA, using generalized estimating equation and linear regression models with adjustments for body mass index, diet, vitamin D intake, education, leisure-time physical activity, and smoking.

RESULTS

Women with inadequate Ca intake (< 800 mg/day) over the follow-up had 3.8% smaller midlife vertebral CSA than women with adequate Ca intake (p = 0.009). Ca intake among men showed no association with vertebral CSA.

CONCLUSIONS

Inadequate Ca intake (< 800 mg/day) from the age of 31 to 46 predicts small vertebral size and thus decreased spinal resilience among middle-aged women. Future studies should confirm these findings and investigate the factors underlying the association of low Ca intake in women but not in men with smaller vertebral size.

Changes in vertebral dimensions in early adulthood - A 10-year follow-up MRI-study

Previous studies have shown that vertebral height increases until the early twenties, but very few studies have been conducted on other vertebral dimensions. Growth in vertebral size is believed to take place in elderly age but not in early adulthood. In this study, we wanted to clarify the potential changes in the dimensions of the lumbar vertebrae during early adulthood. We used the Northern Finland Birth Cohort 1986 as our study material, with a final sample size of 375 individuals. We performed lumbar magnetic resonance imaging (MRI) when the participants were 20 and 30 years of age (baseline and follow-up, respectively). We recorded the width, depth, height, and cross-sectional area (CSA) of the fourth lumbar vertebra (L4) using the MRI scans. We used generalized estimating equation (GEE) models to analyse the data. Men had 7.6%-26.5% larger vertebral dimensions than women at both baseline and follow-up. The GEE models demonstrated that all the studied dimensions increased during the follow-up period among both sexes (p < 0.001). Men had a higher growth rate in vertebral depth and CSA than women (p < 0.001). Among women, small vertebral width (p = 0.001), depth (p = 0.05) and height (p = 0.02) at baseline were associated with a higher vertebral growth rate during the follow-up than among those with large dimensions at baseline. Among men, small baseline width was associated with higher vertebral growth rate (p = 0.001). Our results clearly indicate that vertebral dimensions increase after 20 years of age among both sexes.

The Association of Body Size, Shape and Composition with Vertebral Size in Midlife - The Northern Finland Birth Cohort 1966 Study

Small vertebral size increases the risk of osteoporotic vertebral fractures. Obese individuals have larger vertebral size and potentially lower fracture risk than lean individuals, but scarce data exist on the association between vertebral size and anthropometric measures beyond height, weight, and body mass index (BMI). Here, we evaluated several anthropometric measures (height, weight, BMI, waist circumference, hip circumference, waist-to-hip ratio [WHR], waist-to-height ratio [WHtR], fat mass [FM], lean body mass [LBM], percentage FM [%FM], percentage LBM [%LBM]) as predictors of vertebral cross-sectional area (CSA). We used a representative sample from the Northern Finland Birth Cohort 1966 (n = 1087), with anthropometric measurements from the ages of 31 and 46, bioimpedance analysis from the age of 46, and lumbar magnetic resonance imaging from the age of 46 years. In our data, height and LBM correlated most strongly with vertebral CSA among both sexes (0.469 ≤ r ≤ 0.514), while WHR, WHtR, %FM, and %LBM had the weakest correlations with vertebral CSA (|r| ≤ 0.114). We conclude that height and LBM have the highest, yet only moderate correlations with vertebral size. High absolute LBM, rather than FM or abdominal mass accumulation, correlates with large vertebral size and thus potentially also with lower osteoporotic vertebral fracture risk.

Estimation of stature from dimensions of the fourth lumbar vertebra in contemporary middle-aged Finns

BACKGROUND

Accurate stature estimation plays an essential role in the identification of unknown deceased individuals. For cases in which conventional methods of stature estimation are not applicable, we studied the stature estimation potential of the fourth lumbar vertebra (L4) among a large living sample of representative contemporary Finns. We also generated stature estimation equations for the middle-aged Finnish population.

MATERIAL AND METHODS

Our study population comprised the Northern Finland Birth Cohort 1966 for which lumbar magnetic resonance imaging (MRI) scans and objective measurements of stature were available from midlife (n=1358). After screening the MRI scans for vertebral pathologies, we measured the maximum and minimum widths, depths and heights of the L4 body with high precision and reliability. We then calculated their sums and means together with approximations of vertebral cross-sectional area and volume. By constructing simple and multiple linear regression models around the L4 parameters, we generated equations for stature prediction, and investigated their accuracy on the basis of the adjusted R squared (R²) and standard error of the estimate (SEE) values of the models.

RESULTS

The multiple linear regression models of the mean width, depth and height of L4 yielded the highest prediction accuracies with the lowest prediction errors (for the entire sample, R²=0.621 and SEE=5.635cm; for men, R²=0.306 and SEE=5.125cm; for women, R²=0.367 and SEE=4.640cm).

CONCLUSION

When conventional methods for estimating stature are not applicable, the lumbar vertebrae may be utilized for this purpose. Relatively accurate stature estimates can be given on the basis of only L4 dimensions.

Gravidity, Parity, and Vertebral Dimensions in the Northern Finland Birth Cohort 1966

STUDY DESIGN

A population-based birth cohort study.

OBJECTIVE

To investigate the association between gravidity, parity, and vertebral geometry among middle-aged women.

SUMMARY OF BACKGROUND DATA

Vertebral size is a recognized determinant of vertebral fracture risk. Yet, only a few lifestyle factors that influence vertebral size are known. Pregnancy is a labile period that may affect the maternal vertebral size or shape. The lumbar lordosis angle is permanently deepened by pregnancy, but it remains unclear whether vertebral shape or size contribute to this deepened angle.

METHODS

We aimed to investigate whether gravidity and parity were associated with vertebral cross-sectional area (CSA) and height ratio (anterior height to posterior height) among 705 middle-aged women from the Northern Finland Birth Cohort 1966. We measured the corpus of their fourth lumbar vertebra using magnetic resonance imaging of the lumbar spine at the age of 46. Gravidity and parity were elicited using a questionnaire also at the age of 46. Linear regression analysis was used with adjustments for body mass index, vertebral CSA (height ratio models), and vertebral height (CSA models). We also ran a subgroup analysis that did not include nulliparous women, and we compared nulliparous women with grand multiparous women.

RESULTS

The models found no statistically significant associations between the predictors and outcomes. Crude and adjusted results were highly similar, and the subgroup analyses provided analogous results.

CONCLUSION

Pregnancy, or even multiple pregnancies, do not seem to have long-term effects on vertebral geometry. In order to enhance the prevention of vertebral fractures, future studies should aim to reveal more lifestyle determinants of vertebral size.

LEVEL OF EVIDENCE

3.

Body Mass Index Trajectories From Birth to Midlife and Vertebral Dimensions in Midlife: the Northern Finland Birth Cohort 1966 Study

Vertebral fracture risk is higher among individuals with small vertebral dimensions. Obesity is a global health problem and may also contribute to bone size and fracture risk. In this work we report the association between life course body mass index (BMI) and vertebral cross-sectional area (CSA) in midlife. The Northern Finland Birth Cohort 1966 study with its 46-year follow-up provided the material for this study. A subsample of 780 individuals had attended lumbar magnetic resonance imaging (MRI) at the age of 46 years, and had records of objectively measured BMI from the ages of 0, 7, 15, 31, and 46 years. Of these, MRI-derived data on vertebral size was available for 682 individuals. We identified latent lifelong BMI trajectories by performing latent class growth modeling (LCGM) on the BMI data, and then used sex-stratified linear regression models to compare the identified trajectory groups in terms of midlife vertebral CSA. Gestational age, education years, adult height, lifelong physical activity, lifelong smoking history, and adulthood diet were assessed as potential confounders. Three distinct trajectory groups ("stable slim," "stable average," and "early onset overweight") were identified among both sexes. Comparisons to the stable slim trajectory revealed that vertebral CSA was significantly (p < 0.001) larger among the stable average and early onset overweight trajectories (69.8 and 118.6 mm² larger among men, 57.7 and 106.1 mm² larger among women, respectively). We conclude that lifelong BMI has a positive association with midlife vertebral size among both sexes. Future studies should characterize the mediating factors of this association.

Population reference range for developmental lumbar spinal canal size

BACKGROUND

Considerable variability exists in normal developmental lumbar spinal canal size. This impacts the likelihood of neural compromise. Spinal canal development is complete by 17 years. As diseases incurred thereafter do not knowingly affect the developmental size of the spinal canal, it is reasonable to use a selected population undergoing abdominopelvic computed tomography (CT) examination to determine developmental lumbar spinal canal size.

METHODS

Study approval was granted by the Clinical Research Ethics Committee. Between Feb 2014 and Jan 2015, mid-vertebral spinal canal cross-sectional area (CSA), depth, width, and vertebral body CSA at each level from L1-L5 was measured, using a semi-automated computerized method in 1,080 ambulatory patients (540 males, 540 females, mean age, 50.5±17 years). Patient height and weight was measured.

RESULTS

A reference range for developmental lumbar spinal canal dimensions was developed at each lumbar level for each sex. There was a 34% variation in spinal canal CSA between smallest and largest quartiles. Developmental spinal canal CSA and depth were consistently smallest at L3, enlarging cranially and caudally. Taller people had slightly larger lumbar spinal canals (P<0.0001). Males had larger spinal canal CSAs than females though relative to vertebral body CSA, spinal canal CSA was larger in females. There was no change in spinal canal CSA with age, weight or BMI (P<0.05).

CONCLUSIONS

A population reference range for developmental lumbar spinal canal size was developed. This allows one to objectively determine the degree of developmental spinal canal stenosis present on an individual patient basis.