The previous models for predicting the forces acting on a needle during insertion into very soft organs (such as, e.g. brain) relied on oversimplifying assumptions of linear elasticity and specific experimentally derived functions for determining needle-tissue interactions. In this contribution, we propose a more general approach in which the needle forces are determined directly from the equations of continuum mechanics using fully non-linear finite element procedures that account for large deformations (geometric non-linearity) and non-linear stress-strain relationship (material non-linearity) of soft tissues. We applied these procedures to model needle insertion into a swine brain using the constitutive properties determined from the experiments on tissue samples obtained from the same brain (i.e. the subject-specific constitutive properties were used). We focused on the insertion phase preceding puncture of the brain meninges and obtained a very accurate prediction of the needle force. This demonstrates the utility of non-linear finite element procedures in patient-specific modelling of needle insertion into soft organs such as, e.g. brain.
|Journal||Computer Methods in Biomechanics and Biomedical Engineering|
|Publication status||Published - 2008|
Wittek, A., Dutta Roy, T., Taylor, Z. A., Horton, A. T., Washio, T., Chinzei, K., & Miller, K. (2008). Subject-specific non-linear biomechanical model of needle insertion into brain. Computer Methods in Biomechanics and Biomedical Engineering, 11(2), 135-146. https://doi.org/10.1080/10255840701688095