Lumbar spinal ligament characteristics extracted from stepwise reduction experiments allow for preciser modeling than literature data

Damm, Nicolas; Rockenfeller, Robert; Gruber, Karl Heinz

doi:10.1007/s10237-019-01259-6

Cited by 27 publications

(28 citation statements)

References 41 publications

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“…In particular, the three degree of freedom joint neglects translations permitted by the intervertebral disc, ligaments, and facet joints. While it is possible to improve musculoskeletal models with ligaments (Damm et al, 2019 ) and a better intervertebral disc representation (Wang et al, 2020 ), future work will implement the ligaments, discs, and facet joints in a finite element model of multiple spinal units. This is expected to reduce the impact of idealised musculoskeletal joints on the vertebra of interest.…”

Section: Discussionmentioning

confidence: 99%

Maintaining Bone Health in the Lumbar Spine: Routine Activities Alone Are Not Enough

Favier

McGregor

Phillips

2021

Front. Bioeng. Biotechnol.

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Public health organisations typically recommend a minimum amount of moderate intensity activities such as walking or cycling for two and a half hours a week, combined with some more demanding physical activity on at least 2 days a week to maintain a healthy musculoskeletal condition. For populations at risk of bone loss in the lumbar spine, these guidelines are particularly relevant. However, an understanding of how these different activities are influential in maintaining vertebral bone health is lacking. A predictive structural finite element modelling approach using a strain-driven algorithm was developed to study mechanical stimulus and bone adaptation in the lumbar spine under various physiological loading conditions. These loading conditions were obtained with a previously developed full-body musculoskeletal model for a range of daily living activities representative of a healthy lifestyle. Activities of interest for the simulations include moderate intensity activities involving limited spine movements in all directions such as, walking, stair ascent and descent, sitting down and standing up, and more demanding activities with large spine movements during reaching and lifting tasks. For a combination of moderate and more demanding activities, the finite element model predicted a trabecular and cortical bone architecture representative of a healthy vertebra. When more demanding activities were removed from the simulations, areas at risk of bone degradation were observed at all lumbar levels in the anterior part of the vertebral body, the transverse processes and the spinous process. Moderate intensity activities alone were found to be insufficient in providing a mechanical stimulus to prevent bone degradation. More demanding physical activities are essential to maintain bone health in the lumbar spine.

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Section: Discussionmentioning

confidence: 99%

Maintaining Bone Health in the Lumbar Spine: Routine Activities Alone Are Not Enough

Favier

McGregor

Phillips

2021

Front. Bioeng. Biotechnol.

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“…All passive force-transmitting structures, i.e., intervertebral disks (IVD), ligaments and facet joints, were modeled as nonlinear spring-damper elements (Damm et al. 2019 ). Here, particularly force-length and force-angle characteristics of ligaments and IVD, respectively, were extracted from step-wise reduction experiments (Heuer et al.…”

Section: Model and Methodsmentioning

confidence: 99%

“…Ligament insertion points were set manually (Schünke et al 2015) and counter-checked by neurosurgeons from the university clinic in Mainz. All passive force-transmitting structures, i.e., intervertebral disks (IVD), ligaments and facet joints, were modeled as nonlinear spring-damper elements (Damm et al 2019). Here, particularly force-length and force-angle characteristics of ligaments and IVD, respectively, were extracted from step-wise reduction experiments (Heuer et al 2007) and validated using data on range of motion (Heuer et al 2007) as well as intradiscal pressure (Wilke et al 1996).…”

Section: Modelmentioning

confidence: 99%

“…In this work, we used elementary, individualized multi-body simulation (MBS) models of the lumbar spine (Damm et al. 2019 ), performing flexion movements, to introduce a statistical criterion that may serve as a first step toward describing, detecting, and eventually understanding the cause and effect of the centrode’s location: the (weighted) confidence ellipse as introduced in Sect. 2.4 .…”

Section: Introductionmentioning

confidence: 99%

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Muscle-driven and torque-driven centrodes during modeled flexion of individual lumbar spines are disparate

Rockenfeller

Müller

Damm

et al. 2020

Biomech Model Mechanobiol

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Lumbar spine biomechanics during the forward-bending of the upper body (flexion) are well investigated by both in vivo and in vitro experiments. In both cases, the experimentally observed relative motion of vertebral bodies can be used to calculate the instantaneous center of rotation (ICR). The timely evolution of the ICR, the centrode, is widely utilized for validating computer models and is thought to serve as a criterion for distinguishing healthy and degenerative motion patterns. While in vivo motion can be induced by physiological active structures (muscles), in vitro spinal segments have to be driven by external torque-applying equipment such as spine testers. It is implicitly assumed that muscle-driven and torque-driven centrodes are similar. Here, however, we show that centrodes qualitatively depend on the impetus. Distinction is achieved by introducing confidence regions (ellipses) that comprise centrodes of seven individual multi-body simulation models, performing flexion with and without preload. Muscle-driven centrodes were generally directed superior–anterior and tail-shaped, while torque-driven centrodes were located in a comparably narrow region close to the center of mass of the caudal vertebrae. We thus argue that centrodes resulting from different experimental conditions ought to be compared with caution. Finally, the applicability of our method regarding the analysis of clinical syndromes and the assessment of surgical methods is discussed.

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“…From the calibrated figure 7.14 in a most recent source (Williams and Meyer, 2017), the dimensions of an Australopithecus afarensis L4 endplate can be read off: a width of Accordingly, properly determining endplate areas, just like muscle and ligament lever arms, in extant species or from fossil records are all key to well predicting compressive IVD stresses. As a last example, referring to material properties, it has recently been shown that widely scattering published data on spinal ligament properties, their stiffnesses (Mörl et al, 2020;Damm et al, 2019) and rest lengths (Mörl et al, 2020) in particular, are a source of erroneous calculations of loads on all spinal structures. Consequently, our second major conclusion is that the mechanical function(s) of an anatomical structure, as well as functional interrelations between structures, are desirable to always be kept in mind when experimentally examining and determining anatomical and material properties.…”

Section:  mentioning

confidence: 99%

Giraffes and hominins: reductionist model predictions of compressive loads at the spine base for erect exponents of the animal kingdom

Günther

Mörl²

2020

Biology Open

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In humans, compressive stress on intervertebral discs is commonly deployed as a measurand for assessing the loads that act within the spine. Examining this physical quantity is crucially beneficial: the intradiscal pressure can be directly measured in vivo in humans, and is immediately related to compressive stress. Hence, measured intradiscal pressure data are very useful for validating such biomechanical animal models that have the spine incorporated, and can, thus, compute compressive stress values. Here, we use human intradiscal pressure data to verify the predictions of a reductionist spine model, which has in fact only one joint degree of freedom. We calculate the pulling force of one lumped anatomical structure that acts past this (intervertebral) joint at the base of the spine, lumbar in hominins, cervical in giraffes, to compensate the torque that is induced by the weight of all masses located cranially to the base. Given morphometric estimates of the human and australopith trunks, respectively, and the giraffe's neck, as well as the respective structures’ lever arms and disc areas, we predict, for all three species, the compressive stress on the intervertebral disc at the spine base, while systematically varying the angular orientation of the species’ spinal columns with respect to gravity. The comparison between these species demonstrates that hominin everyday compressive disc stresses are lower than those in big quadrupedal animals. Within each species, erecting the spine from being bent forward by, for example, thirty degrees to fully upright posture reduces the compressive disc stress roughly to a third. We conclude that erecting the spine immediately allows the carrying of extra loads of the order of body weight, and yet the compressive disc stress is lower than in a moderately forward-bent posture with no extra load.

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Lumbar spinal ligament characteristics extracted from stepwise reduction experiments allow for preciser modeling than literature data

Cited by 27 publications

References 41 publications

Maintaining Bone Health in the Lumbar Spine: Routine Activities Alone Are Not Enough

Maintaining Bone Health in the Lumbar Spine: Routine Activities Alone Are Not Enough

Muscle-driven and torque-driven centrodes during modeled flexion of individual lumbar spines are disparate

Giraffes and hominins: reductionist model predictions of compressive loads at the spine base for erect exponents of the animal kingdom

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