Validation method of a middle ear mechanical model to develop a surgical simulator.

Ossicular surgery requires a high dexterity for the manipulation of the fragile and small middle ear components. Currently, the only efficient technique for training residents in otological surgery is through the use of temporal bone specimens, where any existing surgical simulator does not provide useful feedback. The objective of this study was to develop a finite-element model of the human ossicular chain dedicated to surgical simulation and to propose a method to evaluate its behavior. A model was developed based on human middle ear micromagnetic resonance imaging. The mechanical parameters were determined according to published data. To assess its performance, the middle ear transfer function was analyzed. The robustness of our model and the influence of different middle ear components were also evaluated at low frequency by static force pressure simulations. The mechanical behavior of our model in nominal and pathological conditions was in good agreement with published human temporal bone measurements. We showed that the cochlea influences the transfer function only at high frequency and could be omitted from a surgical simulator. In addition, surgeons were able to manipulate the validated middle ear model with a real-time haptic feedback. The computational efficiency of our approach allowed real-time interactions, making it suitable for use in a training simulator.