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Biomechanical analysis and modeling of different vertebral growth patterns in adolescent idiopathic scoliosis and healthy subjects.

Shi L, Wang D, Driscoll M, Villemure I, Chu WC, Cheng JC, Aubin CE - Scoliosis (2011)

Bottom Line: Based on this model, five other geometric models were generated to emulate different coronal and sagittal curves.The detailed modeling integrated vertebral body growth plates and growth modulation spinal biomechanics.Sequential measures of spinal alignments were compared. (1) Given the initial lateral deformity, the AIS growth profile induced a significant Cobb angle increase, which was roughly between three to five times larger compared to measures utilizing a normal growth profile. (2) Lateral deformities were absent in the models containing no initial coronal curvature. (3) The presence of a smaller kyphosis did not produce an increase lateral deformity on its own. (4) Significant reduction of the kyphosis was found in simulation results of AIS but not when using the growth profile of normal subjects.

View Article: PubMed Central - HTML - PubMed

Affiliation: Mechanical Engineering Department, École Polytechnique de Montréal, Montréal, Quebec, Canada. carl-eric.aubin@polymtl.ca.

ABSTRACT

Background: The etiology of AIS remains unclear, thus various hypotheses concerning its pathomechanism have been proposed. To date, biomechanical modeling has not been used to thoroughly study the influence of the abnormal growth profile (i.e., the growth rate of the vertebral body during the growth period) on the pathomechanism of curve progression in AIS. This study investigated the hypothesis that AIS progression is associated with the abnormal growth profiles of the anterior column of the spine.

Methods: A finite element model of the spinal column including growth dynamics was utilized. The initial geometric models were constructed from the bi-planar radiographs of a normal subject. Based on this model, five other geometric models were generated to emulate different coronal and sagittal curves. The detailed modeling integrated vertebral body growth plates and growth modulation spinal biomechanics. Ten years of spinal growth was simulated using AIS and normal growth profiles. Sequential measures of spinal alignments were compared.

Results: (1) Given the initial lateral deformity, the AIS growth profile induced a significant Cobb angle increase, which was roughly between three to five times larger compared to measures utilizing a normal growth profile. (2) Lateral deformities were absent in the models containing no initial coronal curvature. (3) The presence of a smaller kyphosis did not produce an increase lateral deformity on its own. (4) Significant reduction of the kyphosis was found in simulation results of AIS but not when using the growth profile of normal subjects.

Conclusion: Results from this analysis suggest that accelerated growth profiles may encourage supplementary scoliotic progression and, thus, may pose as a progressive risk factor.

No MeSH data available.


Related in: MedlinePlus

Six initial states for the FEM model of spinal column (postero-anterior and sagittal views): Case 1 was reconstructed from a normal subject, and Cases 2~6 were generated from Case 1.
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Figure 2: Six initial states for the FEM model of spinal column (postero-anterior and sagittal views): Case 1 was reconstructed from a normal subject, and Cases 2~6 were generated from Case 1.

Mentions: Based on initial geometry of the patient-specific model, five other spine geometries with different kyphosis angles and lateral curves were generated by varying the spatial orientations of the vertebral bodies and intervertebral discs (Figure 2). Based on these six geometrical models, the corresponding finite element models were generated. The variety of spinal configurations allowed a detailed analysis of the influence of varying growth profiles on spinal alignment.


Biomechanical analysis and modeling of different vertebral growth patterns in adolescent idiopathic scoliosis and healthy subjects.

Shi L, Wang D, Driscoll M, Villemure I, Chu WC, Cheng JC, Aubin CE - Scoliosis (2011)

Six initial states for the FEM model of spinal column (postero-anterior and sagittal views): Case 1 was reconstructed from a normal subject, and Cases 2~6 were generated from Case 1.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3118970&req=5

Figure 2: Six initial states for the FEM model of spinal column (postero-anterior and sagittal views): Case 1 was reconstructed from a normal subject, and Cases 2~6 were generated from Case 1.
Mentions: Based on initial geometry of the patient-specific model, five other spine geometries with different kyphosis angles and lateral curves were generated by varying the spatial orientations of the vertebral bodies and intervertebral discs (Figure 2). Based on these six geometrical models, the corresponding finite element models were generated. The variety of spinal configurations allowed a detailed analysis of the influence of varying growth profiles on spinal alignment.

Bottom Line: Based on this model, five other geometric models were generated to emulate different coronal and sagittal curves.The detailed modeling integrated vertebral body growth plates and growth modulation spinal biomechanics.Sequential measures of spinal alignments were compared. (1) Given the initial lateral deformity, the AIS growth profile induced a significant Cobb angle increase, which was roughly between three to five times larger compared to measures utilizing a normal growth profile. (2) Lateral deformities were absent in the models containing no initial coronal curvature. (3) The presence of a smaller kyphosis did not produce an increase lateral deformity on its own. (4) Significant reduction of the kyphosis was found in simulation results of AIS but not when using the growth profile of normal subjects.

View Article: PubMed Central - HTML - PubMed

Affiliation: Mechanical Engineering Department, École Polytechnique de Montréal, Montréal, Quebec, Canada. carl-eric.aubin@polymtl.ca.

ABSTRACT

Background: The etiology of AIS remains unclear, thus various hypotheses concerning its pathomechanism have been proposed. To date, biomechanical modeling has not been used to thoroughly study the influence of the abnormal growth profile (i.e., the growth rate of the vertebral body during the growth period) on the pathomechanism of curve progression in AIS. This study investigated the hypothesis that AIS progression is associated with the abnormal growth profiles of the anterior column of the spine.

Methods: A finite element model of the spinal column including growth dynamics was utilized. The initial geometric models were constructed from the bi-planar radiographs of a normal subject. Based on this model, five other geometric models were generated to emulate different coronal and sagittal curves. The detailed modeling integrated vertebral body growth plates and growth modulation spinal biomechanics. Ten years of spinal growth was simulated using AIS and normal growth profiles. Sequential measures of spinal alignments were compared.

Results: (1) Given the initial lateral deformity, the AIS growth profile induced a significant Cobb angle increase, which was roughly between three to five times larger compared to measures utilizing a normal growth profile. (2) Lateral deformities were absent in the models containing no initial coronal curvature. (3) The presence of a smaller kyphosis did not produce an increase lateral deformity on its own. (4) Significant reduction of the kyphosis was found in simulation results of AIS but not when using the growth profile of normal subjects.

Conclusion: Results from this analysis suggest that accelerated growth profiles may encourage supplementary scoliotic progression and, thus, may pose as a progressive risk factor.

No MeSH data available.


Related in: MedlinePlus