Appraising efficiency of OpSite as coolant in drilling of bone

Abstract

Background: During drilling of bone, which is common in clinical surgeries, heat generation increases local temperature in the drilling site. Transmission of excessive heat to the surrounding bone tissue can cause thermal osteonecrosis. Consequently, it may lead to failure of implants and fixation screws or delay in healing process. Using cooling is a method for limiting temperature elevation. Materials and methods: In this study, through comparing three conditions of drilling without cooling, external cooling with normal saline, and external cooling with OpSite spray, the efficiency of OpSite as coolant is studied. In this regard, 2 drill bit diameters, 3 drilling speeds, and 3 drilling feed-rates are considered as drilling variables in the experiments. Results: For the whole experiments, while cooling with normal saline resulted in lower maximum temperatures than without cooling condition, OpSite had even better results and limited the temperature elevation during drilling of bone efficiently. Conclusion: OpSite spray, which has lower infection risks than normal saline on one hand and lower maximum temperature rise with all combinations of drilling parameters on the other hand, can be considered in clinical surgeries for cooling applications.

Ultrasonic-Assisted Drilling of Cortical and Cancellous Bone in a Comparative Point of View

“…For in-vitro drilling, ovine lumbar vertebrae was employed which includes both cortical and cancellous bone. Ovine bone is common in orthopaedic animal-experiments due to its similar properties to human bone [7][8][9][10]; however, according to the comparative body of this study, any possible discrepancy in bone properties does not actually hurt deductions [5]. Fresh bones were prepared for drilling according to the literature [11].…”

“…In order to record temperature variations during drilling, we used type K thermocouple [5,16]. The distance between drilling site and thermocouple site was 0.5 mm and the depth in which thermocouple was placed in the bone was 10 mm [5]. In addition, the room temperature was 22 °C and the bones warmed up to the same temperature.…”

“…Hence, during the drilling, it is important to control amount of both the generated heat and the applied force for drilling since the outcome of the surgery depends on them strongly. The necrosis and apoptosis of osteocytes affect 'osseointegration' and the healing process, and can increase risk of loosening and failure in implants and screws [5].…”