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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

Effect of swelling on (A) total intra-level force variation, (B) local muscle strains in standing position with and without previous rest.
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Figure 5: Effect of swelling on (A) total intra-level force variation, (B) local muscle strains in standing position with and without previous rest.

Mentions: When previous lying was considered, muscle forces per level increased linearly in caudal direction in standing position. The maximum muscle resultant force was about 14 N at the lowermost L5/S1 level, i.e., nearly three times the total force calculated at L3/L4 (Figure 5A). Without previous lying, the maximum resultant force was approximately 18 N and was developed at L3/L4. Fascicle strain calculations in simulated standing showed that when previous lying was considered, most of the dorsal fascicles were stretched, whereas the bilateral fascicle contraction changed when no previous rest was considered (Figure 5B). Actually, along the IVD swelling simulated during the 8-h of rest (Figure 6), active forces were developed by the local muscles while the latter were stretched. As shown in Figure 6, L3 and L4 MF and IL fascicles were the most activated ones.


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)

Effect of swelling on (A) total intra-level force variation, (B) local muscle strains in standing position with and without previous rest.
© Copyright Policy
Related In: Results  -  Collection

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

Figure 5: Effect of swelling on (A) total intra-level force variation, (B) local muscle strains in standing position with and without previous rest.
Mentions: When previous lying was considered, muscle forces per level increased linearly in caudal direction in standing position. The maximum muscle resultant force was about 14 N at the lowermost L5/S1 level, i.e., nearly three times the total force calculated at L3/L4 (Figure 5A). Without previous lying, the maximum resultant force was approximately 18 N and was developed at L3/L4. Fascicle strain calculations in simulated standing showed that when previous lying was considered, most of the dorsal fascicles were stretched, whereas the bilateral fascicle contraction changed when no previous rest was considered (Figure 5B). Actually, along the IVD swelling simulated during the 8-h of rest (Figure 6), active forces were developed by the local muscles while the latter were stretched. As shown in Figure 6, L3 and L4 MF and IL fascicles were the most activated ones.

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