A rigid thorax assumption affects model loading predictions at the upper but not lower lumbar levels

Ignasiak, Dominika; Ferguson, Stephen J.; Arjmand, Navid

doi:10.1016/j.jbiomech.2016.07.006

Cited by 43 publications

(29 citation statements)

References 27 publications

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“…The present study focused specifically on investigating loads at lower lumbar levels; however, the lumped modelling assumptions for the thorax could have implications at T12L1, which could be carried over and consequently affect loading predictions in the lower lumbar joints as well. Nonetheless, the rigid thorax assumption was demonstrated to affect loading predictions at the upper but not at the lower lumbar levels [44].…”

Section: Discussionmentioning

confidence: 99%

“…Concerning T12L1, since the AnyBody model characterizes the twelve thoracic vertebrae as a single segment, the relative angle between T12 and L1 was obtained by measuring the slope of the mesh of T12 in the thoracic segment (Fig 1B). The angle ranged from -23° to +11°, whereas in asymptomatic subjects it ranged from -7° to +17° [44]. The larger value in extension (-23°), although moderate, can affect the prediction of loads at T12L1.…”

Section: Discussionmentioning

confidence: 99%

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Dependence of lumbar loads on spinopelvic sagittal alignment: An evaluation based on musculoskeletal modeling

2019

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Still little is known about how spinopelvic alignment affects spinal load distribution. Musculoskeletal modeling can potentially help to discover associations between spine alignment and risk factors of spinal disorders (e.g. disc herniation, vertebral fracture, spondylolisthesis, low back pain). The present study exploited the AnyBody full-body musculoskeletal model to assess the relation between lumbar loads and spinopelvic alignment in the sagittal plane. The model was evaluated in the standing position. The simulated postures were set using spinopelvic parameters gleaned from the literature and characterizing the healthy adult population. The parameters were: sagittal vertical axis, Roussouly lumbar type, sacral slope, and pelvic incidence. A total of 2772 configurations were simulated based on the following measurements: compression force and anterior shear at levels L4L5 and L5S1; multifidus, longissimus spinae, and rectus abdominis muscle forces. Changes in global sagittal alignment, lumbar typology, and sacral inclination, but not in pelvic incidence, were found to affect intervertebral loads in the lumbar spine and spinal muscle activation. Considering these changes would be advantageous for clinical evaluation, due to the recognized relation between altered loads and risk of disc herniation, vertebral fracture, spondylolisthesis, and low back pain. Musculoskeletal modeling proved to be a valuable biomechanical tool to non-invasively investigate the relation between internal loads and anatomical parameters.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Dependence of lumbar loads on spinopelvic sagittal alignment: An evaluation based on musculoskeletal modeling

2019

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“…Although seldomly integrated into models describing human balance and spinal stability (Granata and Wilson, 2001), the rib cage imposes important postural adjustment constraints. Costovertebral joints limit flexion (especially lateral) and rotation of the thoracic spine (Liebsch et al, 2017) and their mechanical properties modulate the force exerted on the upper lumbar spine during trunk flexion (Ignasiak et al, 2016). In addition, breathing involves rotation of the costovertebral joints that modifies spinal curvature and, consequently, spinal postural alignment (Dally, 1908).…”

Section: Introductionmentioning

confidence: 99%

Compensation of Respiratory-Related Postural Perturbation Is Achieved by Maintenance of Head-to-Pelvis Alignment in Healthy Humans

et al. 2019

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The maintenance of upright balance in healthy humans requires the preservation of a horizontal gaze, best achieved through dynamical adjustments of spinal curvatures and a pelvic tilt that keeps the head-to-pelvis alignment close to vertical. It is currently unknown whether the spinal and pelvic compensations of respiratory-related postural perturbations are associated with preservation of the head-to-pelvis vertical alignment. We tested this hypothesis by comparing postural alignment variables at extreme lung volume (total lung capacity, TLC; residual volume, RV) with their reference value at functional residual capacity (FRC). Forty-eight healthy subjects [22 women; median age of 34 (26; 48) years] were studied using low dose biplanar X-rays (BPXR; EOS ® system). Personalized three-dimensional models of the spine and pelvis were reconstructed at the three lung volumes. Extreme lung volumes were associated with changes of thoracic curvature bringing it outside the normal range. Maximal inspiration reduced thoracic kyphosis [T1–T12 angle = 47° (37; 56), -4° variation (-9; 1), p = 0.0007] while maximal expiration induced hyperkyphosis [T1–T12 angle = 63° (55; 68); +10° variation (5; 12), p = 9 × 10 -12 ]. Statistically significant (all p < 0.01) cervical and pelvic compensatory changes occurred [C3–C7 angle: +4° (-2; 11) and pelvic tilt +1° (0; 3) during maximal inspiration; C3–C7 angle: -7° (-18; -1) and pelvic tilt +5° (1; 8) during maximal expiration], resulting in preserved head-to-pelvis alignment (no change in the angle between the vertical plane and the line connecting the odontoid process and the midpoint of the line connecting the center of the two femoral heads ODHA). Lung volume related postural perturbations were more marked as a function of age, but age did not affect the head-to-pelvis alignment. These findings should help understand balance alterations in patients with chronic respiratory diseases that modify lung volume and rib cage geometry.

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“…Incorporation of non-rigid cervical and thoracic spines enables more realistic and detailed investigations of the muscle activation patterns and the spinal loads [40]. These features might be particularly important when studying the joints connecting different regions of the spinal column (for example, C7/T1 joint) as the changes in moment arms of the muscles spanning these joints would be better implemented.…”

Section: Discussionmentioning

confidence: 99%

“…The majority of these models included only a certain region of the spine and assumed a single, lumped, rigid body representation of the thorax or neck. The effects of modeling the thorax this way instead of a flexible structure when estimating the lumbar loads were previously studied for flexion [40]. They found moderately lower compressive disc forces but remarkably altered muscle forces.…”

Section: Introductionmentioning

confidence: 99%

Twente spine model

Bayoğlu¹

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A rigid thorax assumption affects model loading predictions at the upper but not lower lumbar levels

Cited by 43 publications

References 27 publications

Dependence of lumbar loads on spinopelvic sagittal alignment: An evaluation based on musculoskeletal modeling

Dependence of lumbar loads on spinopelvic sagittal alignment: An evaluation based on musculoskeletal modeling

Compensation of Respiratory-Related Postural Perturbation Is Achieved by Maintenance of Head-to-Pelvis Alignment in Healthy Humans

Twente spine model

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