Deformation analysis of lumbar spine based on mechanics of materials and finite element method

Abstract

During the robot-assisted spinal surgery, the patient lies prone on the operation table. The doctor and surgical robot cooperates to conduct the operation. Due to the operating force of surgical instrument, the surgical area of lumbar spine will have a corresponding movement to affect the operation accuracy. In order to improve the operation accuracy, this paper explores this under-constraint environment of the lumbar in the surgery, the lumbar deformation under surgical instruments' force is analyzed and a mathematical model of lumbar's passive motion is proposed. Based on the hypothesis of uniform beam, the relationship between force and displacement of reference point is calculated. The CT images of an adult male's lumbar are segmented and the three-dimensional model is obtained. By using the finite element analysis, the lumbar's model is analyzed and the displacement of reference point under the force of surgical instruments is obtained. According to the results of finite element model, the mathematical model established by mechanics of materials is verified.