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An Anesthesia, Surgery, and Harvest Method for the Evaluation of Transpedicular Screws Using an In Vivo Porcine Lumbar Spine Model
Published on: May 31, 2017
A parametric study of cylindrical pedicle screw design implications on the pullout performance using an
Panagiotis E Chatzistergos1, Evangelos A Magnissalis, Stavros K Kourkoulis
1Unit of Biomechanics, Department of Mechanics, School of Applied Mathematical and Physical Sciences, National Technical University of Athens, Zografou Campus, Theocaris Building, 157-73 Attiki, Greece.
Medical Engineering & Physics
|December 1, 2009
Summary
This study developed a finite-element model to predict pedicle screw pullout force. The model accurately simulates screw failure, identifying outer radius and purchase length as key factors influencing pullout strength.
Area of Science:
- Biomedical Engineering
- Materials Science
- Orthopedic Surgery
Background:
- Pedicle screws are crucial in spinal fixation.
- Accurate prediction of pedicle screw pullout force is essential for surgical success.
- Existing models may not fully capture screw-bone interface failure mechanisms.
Purpose of the Study:
- To design and validate a finite-element model for simulating pedicle screw pullout behavior.
- To accurately predict the pullout force of cylindrical pedicle screws.
- To investigate factors influencing pedicle screw pullout strength.
Main Methods:
- Experimental testing of three commercial pedicle screws under pullout from synthetic bone.
- Development and validation of a finite-element model using experimental data.
- Implementation of a bilinear cohesive zone material model to simulate shear failure at the screw-bone interface.
Main Results:
- The finite-element model accurately simulated pedicle screw pullout behavior and failure.
- The cohesive zone model significantly enhanced the accuracy of numerical simulations.
- Parametric study revealed outer radius and purchase length as major factors influencing pullout force.
Conclusions:
- The developed finite-element model provides a reliable tool for predicting pedicle screw pullout force.
- Optimizing outer radius and purchase length can enhance pedicle screw fixation stability.
- The model aids in understanding screw-bone interaction and improving spinal implant design.
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