A model for studies of the deformable rib cage

Closkey, Robert F.; Schultz, Albert B.; Luchies, Carl W.

doi:10.1016/0021-9290(92)90093-g

Cited by 25 publications

(12 citation statements)

References 28 publications

(34 reference statements)

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“…Despite these injury patterns, little progress has been made toward understanding the loads applied to the thoracic spine during common activities. Existing biomechanical models of the thoracic spine have studied respiratory mechanics, scoliosis, and ribcage deformities (Andriacchi et al, 1974, Closkey et al, 1992, Kong and Goel, 2003, Loring, 1991), rather than forces applied to the thoracic vertebrae. Thus, a biomechanical model capable of estimating forces applied to thoracic vertebrae and exerted by surrounding trunk musculature may provide insights into the etiology of musculoskeletal disorders in this region.…”

Section: Introductionmentioning

confidence: 99%

A biomechanical model for estimating loads on thoracic and lumbar vertebrae

Iyer

Christiansen

Roberts

et al. 2010

Clinical Biomechanics

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Background Biomechanical models are commonly used to estimate loads on the spine. Current models have focused on understanding the etiology of low back pain and have not included thoracic vertebral levels. Using experimental data on the stiffness of the thoracic spine, ribcage, and sternum, we developed a new quasi-static stiffness-based biomechanical model to calculate loads on the thoracic and lumbar spine during bending or lifting tasks. Methods To assess the sensitivity of the model to our key assumptions, we determined the effect of varying ribcage and sternal stiffness, maximum muscle stress, and objective function on predicted spinal loads. We compared estimates of spinal loading obtained with our model to previously reported in vivo intradiscal pressures and muscle activation patterns. Findings Inclusion of the ribs and sternum caused an average decrease in vertebral compressive force of 33% for forward flexion and 18% in a lateral moment task. The impact of maximum muscle stress on vertebral force was limited to a narrow range of values. Compressive forces predicted by our model were strongly correlated to in vivo intradiscal pressure measurements in the thoracic (r=0.95) and lumbar (r=1) spine. Predicted trunk muscle activity was also strongly correlated (r=0.95) with previously published EMG data from the lumbar spine. Interpretation The consistency and accuracy of the model predictions appear to be sufficient to justify the use of this model for investigating the relationships between applied loads and injury to the thoracic spine during quasi-static loading activities.

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Section: Introductionmentioning

confidence: 99%

A biomechanical model for estimating loads on thoracic and lumbar vertebrae

Iyer

Christiansen

Roberts

et al. 2010

Clinical Biomechanics

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“…Thus, knowledge of the costo-vertebral joint behaviour becomes crucial in building a finite-element model of the entire spine including the thoracic cage [2].At the present time, very little information about costovertebral joint behaviour is available in the scientific literature [1,2,4,9]. Furthermore, such information as there is is qualitative rather than quantitative and not useful for mechanical modeling.…”

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confidence: 99%

Characterization of the mechanical behaviour parameters of the costo-vertebral joint

Lemosse

Rue

Diop

et al. 1998

European Spine Journal

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IntroductionThe thoracic cage has an important role in breathing [11] and spine stability, particularly in scoliosis. Thus, knowledge of the costo-vertebral joint behaviour becomes crucial in building a finite-element model of the entire spine including the thoracic cage [2].At the present time, very little information about costovertebral joint behaviour is available in the scientific literature [1,2,4,9]. Furthermore, such information as there is is qualitative rather than quantitative and not useful for mechanical modeling. We aimed to determine the required mechanical data. A preliminary study [3] allowed us to plot some load/displacement curves; however, the measuring systems commonly used by other workers in the field were not suitable for studying such a low-stiffness joint.The objective of this study is to introduce a new method to analyse the three-dimensional (3D) mechanical behaviour of the costo-vertebral joint using an opto-electronic system. Materials and methods Anatomical samplesNine thoracic cages (Table 1) were isolated from fresh cadavers, at an average of 9 days after death (range 4-11 days). The average age of the subjects was 61 years (range 39-71 years), the average weight was 70 kg (range 46-110 kg) and the average height was 167 cm (range 160-180 cm). There were ten males and one female Abstract This in vitro study introduces a new method to determine quantitative parameters characterizing the mechanical behaviour of the costo-vertebral joint. These parameters are useful in building numerical models of the thoracic spine, taking into account the thoracic cage. Nine thoracic cages were isolated from fresh human cadavers. From each cage, three functional units were tested: T1-T2, T5-T6, T9-T10. Loads were applied according to the joint local coordinate system. Every functional unit was tested first intact and again after section of successive costo-transverse ligaments. We used an opto-electronic system to follow the three-dimensional motion of the joint, and obtained non-linear load/displacement curves according to the primary rotation axis. A statistical analysis of these curves allowed the calculation of parameters describing the joint mechanical behaviour: total range of motion, motion in the low-stiffness zone, and flexibilities in the positive and negative quasi-linear zones. These values can be used as a database for mechanical modeling of the spine.

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“…A biomechanical model of the thoracolumbar spine and the rib cage incorporating deformable ribs (10) (Fig. l), developed from earlier models of the spine (8,26) and rib cage incorporating rigid ribs (6), was used.…”

Section: Methodsmentioning

confidence: 99%

“…The model contained 119 rigid bodies, 344 spring elements, and 159 beam elements and had 714 degrees of freedom (df). The validity of this model's representation of behaviors of structurally normal individual ribs and whole rib cages had been tested earlier by comparison of model-predicted deformations with literature reports of observed deformations and was found to be adequate for the purposes of the present study (10).…”

Section: Figmentioning

confidence: 95%

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Rib cage deformities in scoliosis: Spine morphology, rib cage stiffness, and tomography imaging

Closkey

Schultz

1993

Journal Orthopaedic Research

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A computer-implemented biomechanical model of a thoracolumbar spine and deformable rib cage was used to investigate the influence of spine morphology and rib cage stiffness properties on the rib cage deformities that arise from scoliosis and to study the relationship of actual rib distortions with those seen on computed tomography (CT) scans. For the purposes of this study, it was assumed that rib cage deformities result from forces imposed on the ribs by the deforming spine. When a structurally normal rib cage was allowed to follow freely the imposition of scoliotic curves on the spine, different configurations of scoliosis led to substantial differences in the resulting rib cage deformities. Rib cage lateral offset correlated well with the Cobb angle of the scoliosis but not with the apical vertebral axial rotation, whereas rib cage axial rotation correlated well with apical vertebral axial rotation but not with the Cobb angle. These model-obtained findings mirror clinical findings that correction of the Cobb angle leads to correction of the lateral offset of the rib cage but does not correlate well with correction of the rib cage axial rotation. The stiffnesses of the ligamentous tissue connecting the sternum to the pelvis, of the costovertebral joints, and of the ribs themselves also influenced the rib deformities substantially. The influence of the sternopelvic ligamentous ties has not been recognized previously. The total rib cage volume remained essentially constant regardless of the severity of the resulting deformity, but the distribution of this volume between convex and concave sides varied somewhat.(ABSTRACT TRUNCATED AT 250 WORDS)

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A model for studies of the deformable rib cage

Cited by 25 publications

References 28 publications

A biomechanical model for estimating loads on thoracic and lumbar vertebrae

A biomechanical model for estimating loads on thoracic and lumbar vertebrae

Characterization of the mechanical behaviour parameters of the costo-vertebral joint

Rib cage deformities in scoliosis: Spine morphology, rib cage stiffness, and tomography imaging

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