Cutting Torque Model for Patient - Specific Pedicle Screw Surgical Simulators

A novel lattice breakage model as a haptic feedback reference for a channel creation haptic simulator in spine is presented. Human bone materials are anisotropic and constitute 2 types, i.e., cortical (compact) and cancellous (trabecular). The cortical layer is a densely packed bone type whereas the cancellous inner part of bones is porous with bone marrow filling these pores. These different structural integrities dictate the different tactile sensations perceived by surgeons during a surgery. A simplified model of the cutting torque model has been developed by dividing the torque into two parts, namely, base (deterministic) and vibration (stochastic). The base torque reflects the physical model of drilling whereas the lattice breakage torque represents the lattice breakage phenomenon of the elemental bone material. The proposed lattice breakage model is enriched by adding multiple densities.