Modeling and Measurement of Temperature Distributions in Bone Drilling

The heat generated during bone drilling can cause significant thermal damage to the tissue. Hence, prediction of the developing temperature field as a function of the drilling parameters is of high clinical value. However, no experimentally validated model has been reported yet. Furthermore, prior theoretical studies are limited to the drilling process, while extending the analysis beyond drill-bit retraction may be of equal interest. Therefore, the current study aims at experimental validation of a recently published thermal model for temperature distributions both during bone drilling, which is now expanded beyond drill-bit retraction. For validation of the model, a set of experiments was conducted on bovine cortical bone, following the new procedures suggested in the previous study in order to ensure a high degree of accuracy and repeatability. This study is based on thermal data collected at a distance range of 0.15 mm to 0.5 mm from the drilled hole, using thermocouples. Measuring temperatures closer to the drilled hole enabled better understanding of temperature distributions in the tissue in bone drilling. Comparison of experimental data and theoretical simulation results validate the model used. Additionally, about 57°C of difference of the maximum temperatures measured at the radii locations between 0.15 mm and 0.5 mm was observed.