Characterizing the Shape of the Lumbar Spine Using an Active Shape Model

Meakin, Judith R.; Gregory, Jennifer S.; Smith, Francis W.; Gilbert, Fiona J.; Aspden, Richard M.

doi:10.1097/brs.0b013e31816949e6

Cited by 35 publications

(65 citation statements)

References 21 publications

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“…However, the two largest modes of variation found here, 'curviness' (M1) and 'evenness' (M2), describe a similar variation to that previously described [1,3]. Although there is a large variation in spinal shapes between individuals [1,3,[24][25][26], these two modes capture most of this variation and account for between 84 % [1], 91 % [3] and, in this study, 90 % of the total variance. The factors that may underpin the variation in spinal shapes between individuals and possible biomechanical and clinical implications have been discussed previously [3].…”

Section: Discussionsupporting

confidence: 83%

“…Active shape modelling is a precise and reliable method of characterising the shape of the lumbar spine [1,3]. This method has been described in detail previously [3].…”

Section: Active Shape Modellingmentioning

confidence: 99%

“…Statistical shape modelling has previously been used to quantify the variation in spinal shapes between individuals [1]. Commonly used methods to describe lumbar spine curvature have involved measuring the angle between the superior endplates of the first lumbar and first sacral vertebrae and the intervening intersegmental angles.…”

Section: Introductionmentioning

confidence: 99%

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The lumbar spine has an intrinsic shape specific to each individual that remains a characteristic throughout flexion and extension

et al. 2014

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Purpose We have previously shown that the lumbar spine has an intrinsic shape specific to the individual and characteristic of sitting, standing and supine postures. The purpose of this study was to test the hypothesis that this intrinsic shape is detectable throughout a range of postures from extension to full flexion in healthy adults. Methods Sagittal images of the lumbar spine were taken using a positional MRI with participants (n = 30) adopting six postures: seated extension, neutral standing, standing with 30, 45 and 60°and full flexion. Active shape modelling (ASM) was used to identify and quantify 'modes' of variation in the shape of the lumbar spine. Results ASM showed that 89.5 % of the variation in the shape of the spine could be explained by the first two modes; describing the overall curvature and the distribution of curvature of the spine. Mode scores were significantly correlated between all six postures (modes 1-9, r = 0.4-0.97, P \ 0.05), showing that an element of intrinsic shape was maintained when changing postures. The spine was most even in seated extension (P \ 0.001) and most uneven between 35 and 45°flexion (P \ 0.05). Conclusions This study shows that an individual's intrinsic lumbar spine shape is quantifiable and detectable throughout lumbar flexion and extension. These findings will enable the role of lumbar curvature in injury and low back pain to be assessed in the clinic and in the working and recreational environments.

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Section: Discussionsupporting

confidence: 83%

“…Active shape modelling is a precise and reliable method of characterising the shape of the lumbar spine [1,3]. This method has been described in detail previously [3].…”

Section: Active Shape Modellingmentioning

confidence: 99%

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The lumbar spine has an intrinsic shape specific to each individual that remains a characteristic throughout flexion and extension

et al. 2014

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“…The 5 lumbar vertebra were then each individually translated and rotated to match the correct spinal posture. The lumbar lordosis was subsequently compared with data presented in Cholewicki et al (1996) and Meakin et al (2008) to ensure accuracy. The vertebral geometries were correlated with the anatomical studies by Gilad and Nissan (1986), Nissan and Gilad (1986), and those of Panjabi et al (1992), and the intervertebral heights adjusted according to the ratio of vertebral height and disc height.…”

Section: Musculoskeletal Model Resultsmentioning

confidence: 99%

A Musculoskeletal model for the lumbar spine

Christophy

Senan

Lotz

et al. 2011

Biomech Model Mechanobiol

243

205

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A new musculoskeletal model for the lumbar spine is described in this paper. This model features a rigid pelvis and sacrum, the five lumbar vertebrae, and a rigid torso consisting of a lumped thoracic spine and ribcage. The motion of the individual lumbar vertebrae was defined as a fraction of the net lumbar movement about the three rotational degrees of freedom: flexion-extension lateral bending, and axial rotation. Additionally, the eight main muscle groups of the lumbar spine were incorporated using 238 muscle fascicles with prescriptions for the parameters in the Hill-type muscle models obtained with the help of an extensive literature survey. The features of the model include the abilities to predict joint reactions, muscle forces, and muscle activation patterns. To illustrate the capabilities of the model and validate its physiological similarity, the model's predictions for the moment arms of the muscles are shown for a range of flexion-extension motions of the lower back. The model uses the OpenSim platform and is freely available on https://www.simtk.org/home/lumbarspine to other spinal researchers interested in analyzing the kinematics of the spine. The model can also be integrated with existing OpenSim models to build more comprehensive models of the human body.

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“…Only sagittally symmetric tasks were simulated here; the sensitivity of spinal loads to personalized factors may alter in asymmetric tasks although conclusions likely remain unchanged. Changes in the thoracic kyphosis angle or alterations in the initial lordosis (Meakin et al, 2008a) could influence results.…”

Section: Model Evaluationmentioning

confidence: 99%

Effects of sex, age, body height and body weight on spinal loads: Sensitivity analyses in a subject-specific trunk musculoskeletal model

Ghezelbash

Shirazi‐Adl

Arjmand

et al. 2016

Journal of Biomechanics

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Five symmetric sagittal loading conditions were considered, and main effect plots and analyses of variance were employed to identify influential parameters. In all 5 tasks simulated, BW (98.9% in compression and 96.1% in shear) had the greatest effect on spinal loads at the L4-L5 and L5-S1 levels followed by sex (0.7% in compression and 2.1% in shear), BH (0.4% in compression and 1.5% in shear) and finally age (<5.4%). At identical BH and BW, spinal loads in females were slightly greater than those in males by ~4.7% in compression and ~8.7% in shear. In tasks with no loads in hands, BW-normalized spinal loads further increased with BW highlighting the exponential increase in spinal loads with BW that indicates the greater risk of back disorders especially in obese individuals. Uneven distribution of weight in obese subjects, with more 17 BW placed at the lower trunk, further (though slightly <7.5%) increased spinal loads.

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Characterizing the Shape of the Lumbar Spine Using an Active Shape Model

Cited by 35 publications

References 21 publications

The lumbar spine has an intrinsic shape specific to each individual that remains a characteristic throughout flexion and extension

The lumbar spine has an intrinsic shape specific to each individual that remains a characteristic throughout flexion and extension

A Musculoskeletal model for the lumbar spine

Effects of sex, age, body height and body weight on spinal loads: Sensitivity analyses in a subject-specific trunk musculoskeletal model

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