Finite element analysis of stress on thoracic and pedicle screw interface with various loading and bone quality

• Main Authors: Weriono, Rusli, Meifal, Sahputra, Roni Eka, Dahlan, Hendery
• Format: Conference Proceeding
• Language: English
• Subjects: Coefficient of friction; Connectors; Finite element analysis; Finite element method; Fixation; Friction; Friction reduction; Mathematical analysis; Pedicle screws; Spinal curvature; Stress analysis; Stress distribution; Transplants & implants
• ISSN: 0094-243X; 1551-7616
• DOI: 10.1063/5.0103465

Scoliosis is a musculoskeletal condition that has an abnormal lateral spinal curvature as its main feature. By a level of curvature condition, the scoliotic spine has to be treated by surgery process to install implants consisting of pedicle screws, rods, and connectors in fixation of the spinal curvature. However, it is observed in many cases that several types of failure occur in the implant and the bone-pedicle screw interface. One of the problems was related to screw fracture, loosening, and pulled out from the spine. Using finite element analysis, the stress distribution numerically in pedicle the screws and thoracics bone interface in scoliotic spine fixation. The finite element model will analyze how much stress occurs around the interface with variations of bone quality, loading, and friction coefficient. The simulation is carried out using the finite element method. Two types of screws, i.e., cylindrical and conical screws, are implanted to the normal and osteopenia thoracics bone. Two kinds of load, axial and bending load, are applied to the head of the pedicle screw with the friction coefficient of the contact varied about 0.2 and 0.3. The numerical analyses show that the cylindrical screw type of implant has better and lower stress distribution with various loading, bone quality, and friction coefficient than conical type one. Moreover, the increase of friction coefficient affects reducing the stress on the interface bone.