Force parameters evaluation of the foam polyurethane material for the vertebral phantom

Purpose. Phantoms are extensively employed in medicine to replicate the diverse visual, optical, and mechanical properties of the human body parts and organs. In spinal surgery, vertebral phantoms are used to train surgeons and to test robotic medical systems, instruments, and implants. Spinal fusion is the most popular and complicated procedure in spinal surgery. Therefore, one of the current objectives in the manufacturing of vertebral phantoms is to imitate the mechanical properties of bone tissues. Traditionally, compliance assessment of the phantom material with bone tissue is performed by comparing the characteristics obtained during mechanical tests (stretching, compression, torsion) or analyzing the microstructure of the material. Materials. We propose a new method for evaluating bone tissue phantoms, in spinal surgery. This method is based on the analysis of material force parameters calculated from the measured torque of the material deformation during medical instrument insertion into the vertebra. In this study, the values of the material force parameters were determined by inserting pedicle screw and tapping it into polyurethane foams with different compositions. Conclusions. The force parameters of the material for the vertebral cancellous bone tissue phantom can be adjusted by changing the concentration of the components of the polyurethane foam. In addition, holes can be recovered by refilling after surgical manipulations to save the values of the material force parameters of the materials.