scholarly journals Determination of three-dimensional corrective force in adolescent idiopathic scoliosis and biomechanical finite element analysis

2019 ◽  
Author(s):  
Tianmin Guan ◽  
Yu-fang Zhang
Keyword(s):  
Finite Element ◽  
Adolescent Idiopathic Scoliosis ◽  
Idiopathic Scoliosis ◽  
Objective Function ◽  
Soft Tissues ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Maximum Displacement ◽  
Computed Tomography Images ◽  
Three Dimensional Space

Abstract Background: Adolescent idiopathic scoliosis is a complex three-dimensional deformity of spine and soft tissues. It is usually treated with spinal brace if Cobb angle is less than 40°. To date, displacement and rotation of human vertebrae and ribs in three-dimensional space have not been fully considered in treatment of scoliosis. Three dimensional corrective forces in treatment of scoliosis are still unclear and very less attention has paid on it.Methods: An objective function of corrective force in three-dimensional space is defined. Computed tomography images were used to reconstruct three dimensional model of scoliotic trunk. Computer aided engineering software Abaqus was used to establish finite element model of deformed spine and its biomechanical characteristics were analyzed. By adjusting magnitude and position of corrective forces, objective function is minimized to achieve best orthopedic effect. The proposed corrective conditions were divided into three groups: 1. thoracic deformity; 2. lumbar deformity; 3. both thoracic and lumbar deformities were considered.Results: In all three cases, the objective function was reduced by 58%, 52%, and 63%, respectively. The best correction force point is located on convex side of maximum displacement of vertebral body.Conclusions: Using minimum objective function method, spinal deformity in three-dimensional space can be sufficiently reduced. This study provides scientific basis for design of a new corrective brace for treatment of scoliosis.

scholarly journals Assessment of adolescent idiopathic scoliosis from body scanner image by finite element simulations

PLoS ONE ◽  
2021 ◽  
Vol 16 (2) ◽  
pp. e0243736
Author(s):  
Alexander T. D. Grünwald ◽  
Susmita Roy ◽  
Ana Alves-Pinto ◽  
Renée Lampe
Keyword(s):  
Finite Element ◽  
Adolescent Idiopathic Scoliosis ◽  
Idiopathic Scoliosis ◽  
Vertebral Column ◽  
Three Dimensional ◽  
Axial Rotation ◽  
Patient Specific ◽  
X Rays ◽  
Spinal Curvatures ◽  
Body Scanner

Adolescent idiopathic scoliosis, is a three-dimensional spinal deformity characterized by lateral curvature and axial rotation around the vertical body axis of the spine, the cause of which is yet unknown. The fast progression entails regular clinical monitoring, including X-rays. Here we present an approach to evaluate scoliosis from the three-dimensional image of a patient’s torso, captured by an ionizing radiation free body scanner, in combination with a model of the ribcage and spine. A skeletal structure of the ribcage and vertebral column was modelled with computer aided designed software and was used as an initial structure for macroscopic finite element method simulations. The basic vertebral column model was created for an adult female in an upright position. The model was then used to simulate the patient specific scoliotic spine configurations. The simulations showed that a lateral translation of a vertebral body results in an effective axial rotation and could reproduce the spinal curvatures. The combined method of three-dimensional body scan and finite element model simulations thus provide quantitative anatomical information about the position, rotation and inclination of the thoracic and lumbar vertebrae within a three-dimensional torso. Furthermore, the simulations showed unequal distributions of stress and strain profiles across the intervertebral discs, due to their distortions, which might help to further understand the pathogenesis of scoliosis.

scholarly journals Equilibrium of Two-Dimensional Cycloidal Pantographic Metamaterials in Three-Dimensional Deformations

Symmetry ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 1523 ◽  
Author(s):  
Daria Scerrato ◽  
Ivan Giorgio
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Variational Formulation ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Two Dimensional ◽  
Element Analysis ◽  
Elastic Continuum ◽  
Bias Extension ◽  
Three Dimensional Space

A particular pantographic sheet, modeled as a two-dimensional elastic continuum consisting of an orthogonal lattice of continuously distributed fibers with a cycloidal texture, is introduced and investigated. These fibers conceived as embedded beams on the surface are allowed to be deformed in a three-dimensional space and are endowed with resistance to stretching, shearing, bending, and twisting. A finite element analysis directly derived from a variational formulation was performed for some explanatory tests to illustrate the behavior of the newly introduced material. Specifically, we considered tests on: (1) bias extension; (2) compressive; (3) shear; and (4) torsion. The numerical results are discussed to some extent. Finally, attention is drawn to a comparison with other kinds of orthogonal lattices, namely straight, parabolic, and oscillatory, to show the differences in the behavior of the samples due to the diverse arrangements of the fibers.

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