Finite Element Modeling and Analysis of Ultrasonically-Assisted Drilling of Bone

Drilling in bone is a common surgical procedure in orthopedics for fixation and reconstructive surgeries. Research in this area is largely focused on investigating alternate drilling techniques for minimal destruction to the bone tissue. This study measured temperature and force generated during conventional drilling (CD) and ultrasonically-assisted drilling (UAD) using Finite Element (FE) simulations. Three-dimensional FE model of bone drilling was developed and analyzed to simulate the dynamic processes involved in the process. Numerical simulation predicted lower drilling force and temperature in UAD compared to CD using controlled ultrasonic parameters (frequency -- 20kHz, amplitude = 10 micrometers). Drilling tests are performed on fresh bovine femur using surgical drills in the presence of ultrasonic vibrations imposed on the drill in the cutting direction. Force and temperature generation at various depths are calculated and compared for the prescribed drilling techniques. The results obtained from numerical simulations are compared with bone drilling experiments.