Modeling and verification of cortical bone drilling temperature considering heterogeneous structures.

Establishing a mature and reliable cortical bone drilling temperature model is the basis for predicting the size of the danger zone for bone thermal damage (Z Temperature ≥ 47 °C) during drilling. In this paper, the temperature field of cortical bone drilling process is comprehensively analyzed, and proposes a drilling temperature model by considering the heterogeneous structure of cortical bone and combining empirical and analytical methods. The cortical bone drilling temperature model is verified by cortical bone drilling experiments. The hole wall temperature and thermal damage area during drilling with a common drill and a developed chisel-edge thinning drill are compared. The experimental results show that the prediction error of the drilling temperature model considering the heterogeneous tissue structure of cortical bone is within 10 %, and the temperature changes of the tissue structure at different positions away from the periosteum of the cortical bone can be predicted more accurately during the drilling process. Compared with ordinary drill bits, chisel edge thinning drill bits have higher drilling efficiency and excellent chip removal ability. The hole wall temperature and thermal damage area during drilling are reduced by 5.1 %–17.2 % and 10.3 %–42.8 %, respectively. This study is helpful to help surgeons develop strategies for reducing temperature and damage. • An empirical model of friction temperature rise between drill bit and hole wall is established by RSM. • A drilling temperature model considering the heterogeneous structure of cortical bone is proposed. • Compared with common drills, the drilling temperature and thermal damage of chisel-thinning drills are lower. [ABSTRACT FROM AUTHOR]