Ravali Gourishetti

My project is to develop analytical models for needle insertion (a special case of epidural anesthesia) including the biomechanical and psychophysical concepts that simulate the needle-tissue interaction forces in linear heterogeneous tissues and to validate the model with a series of experiments. A four-element Burger’s model is used to correlate the compression force to the tissue deformation. The fracture mechanics model is used to relate the fracture toughness to the tissue deformation. A novel friction model which has the dependency on the needle diameter is used to relate the frictional force to the tissue deformation. The perceptual filter is applied over the biomechanical models using two parameters, force and stiffness perception thresholds. The biomechanical and perception models are validated with experiments in two stages: one, without the human intervention and the other, with the human intervention. The second stage is the validation using the Turing test with two different experiments 1) to study the perceptual difference between the simulated and the physical phantom model 2) to verify the effectiveness of perceptual filter on the biomechanical model. The results from the first experiment show that the participants tend to perceive the physical phantom model as the simulated model for at least 50% of the times. The results from the second experiment show that the participant couldn’t differentiate between the perceptual filtered and the unfiltered model. In conclusion, the experiments showed that the model could replicate the physical phantom tissues with good accuracy. This can be further extended to a non-linear heterogeneous model.