Temperature Increase Limitation During Automatic Bone Drilling in Orthopedic Surgery.

In orthopedic surgery, the most performed manipulation is bone drilling. One significant problem related to this manipulation is the overheating which causes thermal osteonecrosis. By reports the drill speed is the main factor responsible for heat generation and contributes up to 78% to temperature rise during bone drilling. Therefore, the aim of this work is to develop and implement drilling speed control approach to control the temperature rise in drilling area and prevent overheating of bone tissue. During drilling, a real-time drill bit tip temperature estimation is calculated based on data from a non-contact temperature sensor and information from the robot control system. This way, temperature feedback during drilling process is realized. Further, on the base of modified PI controller the target speed depending on the increase in the drill bit tip temperature is calculated. Applying the drill speed control approach, the experimental results showed a decrease in the maximum temperature on the drill bit tip during drilling by up to 13 °C was observed, and the temperature rise was limited to 65-70 °C, with values above 65 °C lasting less than 2 s. The novelty of this work is the realization of temperature feedback and drill speed control approach during drilling process. Applying them in a robotic bone drilling process, the temperature increase in the instrument-bone area was significantly limited, the critical temperature values at which thermal osteonecrosis occurs were not reached, and that substantially reduces the likelihood of thermal osteonecrosis during drilling.