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Abstract This study explores the mechanical interactions between surgical needles and soft tissues during procedures like biopsies and brachytherapy. A key challenge is needle tip deflection, which can cause deviation from the intended target. The study aims to develop an analytical model that predicts needle tip deflection during insertion by combining principles from interfacial mechanics and soft tissue deformation. A modified version of the dynamic Euler-Bernoulli beam theory is employed to model needle insertion and predict needle tip deflection. The model’s predictions are then compared to experimental data obtained from needle insertions in real tissues. The research aims to deepen our understanding of needle-tissue interactions and develop a reliable model for predicting needle deflection, ultimately enhancing surgical robots and navigation systems for safer and more precise percutaneous procedures. Pig organs are used as a material data source for a viscoelastic model, simulating needle insertion into kidney-like environments and analyzing organ deformation. The modified Euler-Bernoulli beam theory considers the viscoelastic properties of the tissue. Deflection is then calculated and compared to experimental data, with analytical deflection measurements exhibiting a 5–10% difference compared to experimental results. 

Abstract Considerable research efforts have been devoted for studying the interaction between surgical needles and soft tissues which can be used to evaluate the deflection of a bevel-tip needle inside a tissue. The development of an analytical model to predict the steering behavior of the needle during needle-tissue interactions could improve the performance of many percutaneous needle-based procedures. In this study, Euler-Bernoulli beam elastic foundation theory was utilized to model the needle as a cantilever beam moving along its longitudinal axis and undergoing various external loads. The external loads are the result of the interaction between the tissue and the needle during insertion, they can be modeled as a concentrated tissue cutting force acting at the needle bevel, and needle-tissue interaction forces acting along the needle length and tangent to the needle shaft. The accuracy of the analytical predictions offered by the model are verified by comparing them to the experimental data. Due to the assumption of the elastic tissue material, the difference between the analytical model and the experimental results was between 15% to 33%. Current work is ongoing to consider tissue viscoelastic properties to improve the analytical prediction.