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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

(A) Total force and (B) active force predictions per fascicle and per level in standing position with and without previous rest. On the vertical axis, the abbreviated name of the fascicles was informed by codifying the insertions: SP, spinous process; LAM, Lamina; VB, vertebral body. As for “A” and “B,” it simply says that the same fascicle has two components “A” and “B.”
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Figure 4: (A) Total force and (B) active force predictions per fascicle and per level in standing position with and without previous rest. On the vertical axis, the abbreviated name of the fascicles was informed by codifying the insertions: SP, spinous process; LAM, Lamina; VB, vertebral body. As for “A” and “B,” it simply says that the same fascicle has two components “A” and “B.”

Mentions: In standing position without previously simulated rest, force calculations revealed activation of the PS and of all dorsal muscles, and a low contribution of the thoracic fascicles. At the upper levels (L3/L4, L4/L5), MF and IL fascicles transferred significant compression forces between nearly 3.5 and 6.5 N to the vertebrae and to the IVDs over which they span (Figure 4A). Among the local back muscles, the highest active forces were estimated for the MF fascicles arising from L5 (Figure 4B) that accounted for more than 1.5 N over a total of nearly 6 N force developed at this level. For the PS fascicles, the total compression forces developed were up to 1 N with relatively high contribution of positive active forces mainly in the upper region (Figure 4B). When previous rest was simulated, increased force activation was predicted for the caudal dorsal fascicles with positive total forces of up to about 7 N. For MF, active forces over 2 N were predicted at the lumbosacral level. For the global fascicles, PS fascicles were less activated at all levels and developed compression forces that did not exceed 0.13 N at L5/S1 level. Contribution of LTpTh remained low.


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)

(A) Total force and (B) active force predictions per fascicle and per level in standing position with and without previous rest. On the vertical axis, the abbreviated name of the fascicles was informed by codifying the insertions: SP, spinous process; LAM, Lamina; VB, vertebral body. As for “A” and “B,” it simply says that the same fascicle has two components “A” and “B.”
© Copyright Policy
Related In: Results  -  Collection

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

Figure 4: (A) Total force and (B) active force predictions per fascicle and per level in standing position with and without previous rest. On the vertical axis, the abbreviated name of the fascicles was informed by codifying the insertions: SP, spinous process; LAM, Lamina; VB, vertebral body. As for “A” and “B,” it simply says that the same fascicle has two components “A” and “B.”
Mentions: In standing position without previously simulated rest, force calculations revealed activation of the PS and of all dorsal muscles, and a low contribution of the thoracic fascicles. At the upper levels (L3/L4, L4/L5), MF and IL fascicles transferred significant compression forces between nearly 3.5 and 6.5 N to the vertebrae and to the IVDs over which they span (Figure 4A). Among the local back muscles, the highest active forces were estimated for the MF fascicles arising from L5 (Figure 4B) that accounted for more than 1.5 N over a total of nearly 6 N force developed at this level. For the PS fascicles, the total compression forces developed were up to 1 N with relatively high contribution of positive active forces mainly in the upper region (Figure 4B). When previous rest was simulated, increased force activation was predicted for the caudal dorsal fascicles with positive total forces of up to about 7 N. For MF, active forces over 2 N were predicted at the lumbosacral level. For the global fascicles, PS fascicles were less activated at all levels and developed compression forces that did not exceed 0.13 N at L5/S1 level. Contribution of LTpTh remained low.

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