Cortical bone drilling: A time series experimental analysis of thermal characteristics

Abstract

Bone drilling is an essential and technically demanding procedure in many forms of surgery. The thermal characteristics in the drilling process directly affect thermal damage to the bone and postoperative recovery. In this study, a comprehensive experimental investigation was conducted to understand the thermal characteristics during cortical bone drilling using a bone cutting system coupled with a state-of-the-art infrared thermography and a dynamometer. The time-series temperature distributions, temperature history at different locations, and quasi-three-dimensional maximum temperature distributions were established and analyzed. The results show that the chisel edge, cutting lips, and margin are the main heat sources during bone drilling. The maximum temperature was generated by the cutting lip. Drilling in three feeding directions was performed to investigate the bone anisotropy. However, no sign of anisotropy on the temperature distribution was observed. But the maximum temperature and overheat duration exhibited a significant variation because of differences in the removal mechanism and bone density. Moreover, the effects of processing parameters on the thermal characteristics were analyzed in terms of the failure mechanism of bone. The drilling process duration may be the governing factor that can finally determine the thermal damage. This is the first study to reveal the thermal characteristics in full detail at the drill-exit with respect to the bone properties, processing parameters, drill-bit geometries, and inclined drilling. These results provide a fundamental understanding of the thermal characteristics in bone drilling and subsequently contribute to the formulation of various strategies for reducing the thermal damage to the bone.