Effects of rotary ultrasonic bone drilling on cutting force and temperature in the human bones

Abstract

Efficacy and outcomes of osteosynthesis depend on various factors including types of injury and repair, host factors, characteristics of implant materials and type of implantation. One of the most important host factors appears to be the extent of bone damage due to the mechanical force and thermal injury which are produced at cutting site during bone drilling. The temperature above the critical temperature (47 °C) produces thermal osteonecrosis in the bones. In the present work, experimental investigations were performed to determine the effect of drilling parameters (rotational speed, feed rate and drill diameter) and techniques (conventional surgical bone drilling and rotary ultrasonic bone drilling) on cutting force and temperature generated during bone drilling. The drilling experiments were performed by a newly developed bone drilling machine on different types of human bones (femur, tibia and fibula) having different biological structure and mechanical behaviour. The bone samples were procured from male cadavers with the age of second to fourth decades. The results revealed that there was a significant difference ( p < 0.05) in cutting force and temperature rise for rotary ultrasonic bone drilling and conventional surgical bone drilling. The cutting force obtained in rotary ultrasonic bone drilling was 30%–40%, whereas temperature generated was 50%–55% lesser than conventional surgical bone drilling process for drilling in all types of bones. It was also found that the cutting force increased with increasing feed rate, drill diameter and decrease in rotational speed, whereas increasing rotational speed, drill diameter and feed rate resulted in higher heat generation during bone drilling. Both the techniques revealed that the axial cutting force and the temperature rise were significantly higher in femur and tibia compared with the fibula for all combinations of process parameters.

Thermal changes during drilling in human femur by rotary ultrasonic bone drilling machine: A histologic and ultrastructural study

“…The drilling parameters (Table 1) were carefully chosen on the base of prior experiences of our group 17,18,30 . It was observed in our prior studies 17,18,22 that among different drilling parameters, rotational speed was the most significant input parameter on temperature rise in bone drilling. In this study, rotational speed, therefore, has been variable; whereas, other parameters have been kept constant (Table 1).…”

“…The drilling time which plays a significant role in temperature during drilling is related to feed rate that is, the linear movement of the rotating tool (along the axis of rotation) as it penetrates in the bone surface, per unit time. The feed rate in the present study was kept constant to 10 mm/min as it was reported in our previous study 22,24 that a higher feed rate resulted in higher cutting force and resulted in mechanical damage of the bone. Lower feed rate resulted in longer drilling time and resulted in higher temperature rise, but higher feed rates (above 50 mm/min) were associated with higher cutting forces and generation of microcracks on the drilled surface of the hole 31‐33 .…”

“…Prior studies on human and porcine femur have shown that the RUBD process is superior to the CD process and produces lesser cutting force, 23,28 temperature rise, 22,30 mechanical damage to the bone surface. 24 Hence, RUBD has the potential to be used in surgical theater in the near future.…”

“…Previous studies have been performed primarily on animal bones using heavy, bulky computer numerical control (CNC) and lathe machines, which are unsuitable for their use in operation theater (OT). 5,[7][8][9][19][20][21] Our previous studies [22][23][24] revealed that drilling by RUBD technique not only reduced the temperature but also decreased the cutting force exerted on the bone. Hence, resulted in lesser mechanical damage and microcracks, and improved the strength between the cortical screw and bone.…”

Statistical Modeling, Optimization and Sensitivity Analysis of Tool’s Geometrical Parameters on Process Force in Automatic Cortical Bone Drilling Process

“…There are some reports addressing the minimization of the axial force in the literature. Singh et al [1] compared the effects of rotational speed, feed rate and tool diameter on cutting *Corresponding Author Institutional Email: m.safari@arakut.ac.ir (Mehdi Safari) force and temperature in conventional and rotary ultrasonic bone drilling. They concluded that the cutting force up to 40% and temperature up to 55% were lesser in rotary ultrasonic technique.…”