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Musculoskeletal Modeling of the Lumbar Spine to Explore Functional Interactions between Back Muscle Loads and Intervertebral Disk Multiphysics.

Toumanidou T, Noailly J - Front Bioeng Biotechnol (2015)

Bottom Line: Calculations led to intradiscal pressure values within ranges of values measured in vivo.Our simulations pointed out a likely existence of a functional balance between stretch-induced muscle activation and IVD multiphysics toward improved mechanical stability of the lumbar spine understanding.This balance suggests that proper night rest contributes to mechanically strengthen the spine during day activity.

View Article: PubMed Central - PubMed

Affiliation: Institute for Bioengineering of Catalonia , Barcelona , Spain ; Department of Information and Communication Technologies, Universitat Pompeu Fabra , Barcelona , Spain.

ABSTRACT
During daily activities, complex biomechanical interactions influence the biophysical regulation of intervertebral disks (IVDs), and transfers of mechanical loads are largely controlled by the stabilizing action of spine muscles. Muscle and other internal forces cannot be easily measured directly in the lumbar spine. Hence, biomechanical models are important tools for the evaluation of the loads in those tissues involved in low-back disorders. Muscle force estimations in most musculoskeletal models mainly rely, however, on inverse calculations and static optimizations that limit the predictive power of the numerical calculations. In order to contribute to the development of predictive systems, we coupled a predictive muscle model with the passive resistance of the spine tissues, in a L3-S1 musculoskeletal finite element model with osmo-poromechanical IVD descriptions. The model included 46 fascicles of the major back muscles that act on the lower spine. The muscle model interacted with activity-related loads imposed to the osteoligamentous structure, as standing position and night rest were simulated through distributed upper body mass and free IVD swelling, respectively. Calculations led to intradiscal pressure values within ranges of values measured in vivo. Disk swelling led to muscle activation and muscle force distributions that seemed particularly appropriate to counterbalance the anterior body mass effect in standing. Our simulations pointed out a likely existence of a functional balance between stretch-induced muscle activation and IVD multiphysics toward improved mechanical stability of the lumbar spine understanding. This balance suggests that proper night rest contributes to mechanically strengthen the spine during day activity.

No MeSH data available.


Related in: MedlinePlus

Schematic diagram of the model input and output and the simulations carried out.
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Figure 3: Schematic diagram of the model input and output and the simulations carried out.

Mentions: For all simulations, the lower endplate of the L5/S1 IVD as well as the upper facets of S1 and the sacral and pelvic muscle insertions were fixed in all directions. External pore pressure was nil at the external boundaries of all IVDs. All calculations were performed with the implicit FE solver Abaqus/Standard (6.12. Simulia, Providence, RI, USA). Muscle forces were predicted per group, per fascicle, and per level, and the relative contribution of the muscle model constitutive terms was calculated in both lying and standing positions. The effect of previous swelling on intra-level force distribution was quantified in simulated standing. We also calculated the intradiscal pressure (IDP) at the center of the NP (Supplementary Material) for all IVDs, and explored the effect of muscle activation on these calculations. Figure 3 shows a schematic diagram of the model input and output and the simulation cases discussed in this paper.


Musculoskeletal Modeling of the Lumbar Spine to Explore Functional Interactions between Back Muscle Loads and Intervertebral Disk Multiphysics.

Toumanidou T, Noailly J - Front Bioeng Biotechnol (2015)

Schematic diagram of the model input and output and the simulations carried out.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4525063&req=5

Figure 3: Schematic diagram of the model input and output and the simulations carried out.
Mentions: For all simulations, the lower endplate of the L5/S1 IVD as well as the upper facets of S1 and the sacral and pelvic muscle insertions were fixed in all directions. External pore pressure was nil at the external boundaries of all IVDs. All calculations were performed with the implicit FE solver Abaqus/Standard (6.12. Simulia, Providence, RI, USA). Muscle forces were predicted per group, per fascicle, and per level, and the relative contribution of the muscle model constitutive terms was calculated in both lying and standing positions. The effect of previous swelling on intra-level force distribution was quantified in simulated standing. We also calculated the intradiscal pressure (IDP) at the center of the NP (Supplementary Material) for all IVDs, and explored the effect of muscle activation on these calculations. Figure 3 shows a schematic diagram of the model input and output and the simulation cases discussed in this paper.

Bottom Line: Calculations led to intradiscal pressure values within ranges of values measured in vivo.Our simulations pointed out a likely existence of a functional balance between stretch-induced muscle activation and IVD multiphysics toward improved mechanical stability of the lumbar spine understanding.This balance suggests that proper night rest contributes to mechanically strengthen the spine during day activity.

View Article: PubMed Central - PubMed

Affiliation: Institute for Bioengineering of Catalonia , Barcelona , Spain ; Department of Information and Communication Technologies, Universitat Pompeu Fabra , Barcelona , Spain.

ABSTRACT
During daily activities, complex biomechanical interactions influence the biophysical regulation of intervertebral disks (IVDs), and transfers of mechanical loads are largely controlled by the stabilizing action of spine muscles. Muscle and other internal forces cannot be easily measured directly in the lumbar spine. Hence, biomechanical models are important tools for the evaluation of the loads in those tissues involved in low-back disorders. Muscle force estimations in most musculoskeletal models mainly rely, however, on inverse calculations and static optimizations that limit the predictive power of the numerical calculations. In order to contribute to the development of predictive systems, we coupled a predictive muscle model with the passive resistance of the spine tissues, in a L3-S1 musculoskeletal finite element model with osmo-poromechanical IVD descriptions. The model included 46 fascicles of the major back muscles that act on the lower spine. The muscle model interacted with activity-related loads imposed to the osteoligamentous structure, as standing position and night rest were simulated through distributed upper body mass and free IVD swelling, respectively. Calculations led to intradiscal pressure values within ranges of values measured in vivo. Disk swelling led to muscle activation and muscle force distributions that seemed particularly appropriate to counterbalance the anterior body mass effect in standing. Our simulations pointed out a likely existence of a functional balance between stretch-induced muscle activation and IVD multiphysics toward improved mechanical stability of the lumbar spine understanding. This balance suggests that proper night rest contributes to mechanically strengthen the spine during day activity.

No MeSH data available.


Related in: MedlinePlus