Multi-objective optimization of surgical drill bit to minimize thermal damage in bone-drilling

2019 ◽  
Vol 157 ◽  
pp. 113594 ◽  
Author(s):  
Mohd Faizal Ali Akhbar ◽  
Ahmad Razlan Yusoff
Keyword(s):  
Thermal Damage ◽  
Drill Bit ◽  
Multi Objective Optimization ◽  
Bone Drilling ◽  
Multi Objective

Investigation, sensitivity analysis, and multi-objective optimization of effective parameters on temperature and force in robotic drilling cortical bone

2017 ◽  
Vol 231 (11) ◽  
pp. 1012-1024 ◽  
Author(s):  
Vahid Tahmasbi ◽  
Majid Ghoreishi ◽  
Mojtaba Zolfaghari
Keyword(s):  
Sensitivity Analysis ◽  
Feed Rate ◽  
Process Temperature ◽  
Drilling Process ◽  
Drilling Speed ◽  
Multi Objective Optimization ◽  
Bone Drilling ◽  
Multi Objective ◽  
Tool Diameter ◽  
First Time

The bone drilling process is very prominent in orthopedic surgeries and in the repair of bone fractures. It is also very common in dentistry and bone sampling operations. Due to the complexity of bone and the sensitivity of the process, bone drilling is one of the most important and sensitive processes in biomedical engineering. Orthopedic surgeries can be improved using robotic systems and mechatronic tools. The most crucial problem during drilling is an unwanted increase in process temperature (higher than 47 °C), which causes thermal osteonecrosis or cell death and local burning of the bone tissue. Moreover, imposing higher forces to the bone may lead to breaking or cracking and consequently cause serious damage. In this study, a mathematical second-order linear regression model as a function of tool drilling speed, feed rate, tool diameter, and their effective interactions is introduced to predict temperature and force during the bone drilling process. This model can determine the maximum speed of surgery that remains within an acceptable temperature range. Moreover, for the first time, using designed experiments, the bone drilling process was modeled, and the drilling speed, feed rate, and tool diameter were optimized. Then, using response surface methodology and applying a multi-objective optimization, drilling force was minimized to sustain an acceptable temperature range without damaging the bone or the surrounding tissue. In addition, for the first time, Sobol statistical sensitivity analysis is used to ascertain the effect of process input parameters on process temperature and force. The results show that among all effective input parameters, tool rotational speed, feed rate, and tool diameter have the highest influence on process temperature and force, respectively. The behavior of each output parameters with variation in each input parameter is further investigated. Finally, a multi-objective optimization has been performed considering all the aforementioned parameters. This optimization yielded a set of data that can considerably improve orthopedic osteosynthesis outcomes.

Mechanical and thermal damage in cortical bone drilling in vivo

2019 ◽  
Vol 233 (6) ◽  
pp. 621-635 ◽  
Author(s):  
Yue Zhang ◽  
Linlin Xu ◽  
Chengyong Wang ◽  
Zhihua Chen ◽  
Shuai Han ◽  
...  
Keyword(s):  
Thermal Damage ◽  
Bone Matrix ◽  
Haversian Canal ◽  
Drill Bit ◽  
Bone Drilling ◽  
Drilling Force ◽  
Drilling Parameters ◽  
Bone Damage ◽  
Empty Lacuna

Recently, the failure rate of fracture fixation to fractured bone has increased. Mechanical and thermal damage to the bone, which influences the contact area and cell growth between the bone and the screw, is the primary reason for fixation failure. However, research has mainly focused on force and temperature in bone drilling. In this study, the characteristics of hole edges, microcracks, empty lacunae, and osteon necrosis were investigated as viewed in the transverse and longitudinal sections after drilling. Drilling force and temperature were also recorded for comparing the relationship with mechanical and thermal damage. Experiments were conducted in vivo using five different drill geometries under the same drilling parameters. Characteristics of the hole wall were detected using computed tomography. Microcracks and necrosis were analyzed using the pathological sectioning method. The maximum microcrack was approximately 3000 and 1400 μm in the transverse section and longitudinal section, respectively, which were much larger than those observed in previous studies. Empty lacuna and osteon necrosis, starting from the Haversian canal, were also found. The drill bit geometry, chisel edge, flute number, edges, and steps had a strong effect on bone damage, particularly the chisel edge. The standard and classic surgical drill caused the greatest surface damage and necrosis of the five drill bit geometries studied. The microstructural features including osteons and matrix played an important role in numbers and length of microcracks and necrosis. More microcracks were generated in the transverse direction, while a greater length of the empty lacuna was generated in the longitudinal direction under the same drilling parameters. Microcracks mainly propagated in a straight manner in and parallel to the interstitial bone matrix and cement line. Drilling forces were not directly correlated with bone damage; thus, hole performance should be considered to evaluate the superiority and inferiority of drill bits rather than the drill force alone.

An Experimental Investigation of Forces on Cortical Bone in Deep-Hole Bone Drilling

2020 ◽  
Vol 3 (3) ◽  
Author(s):  
JuEun Lee ◽  
Serena Y. Chu
Keyword(s):  
Thermal Damage ◽  
Thrust Force ◽  
Chip Morphology ◽  
Drill Bit ◽  
Twist Drill ◽  
Deep Hole ◽  
Bone Drilling ◽  
Drilling Depth ◽  
Abnormal State ◽  
Different Depths

Abstract Deep-hole bone drilling is critical in many surgical implantation procedures. Unlike most common bone-drilling processes, deep-hole bone drilling is performed using a high drilling depth to drill-bit diameter ratio, which can lead to undesirable mechanical and thermal damage during surgical procedures. The objective of this study was to investigate the thrust force and torque generated in deep-hole bone drilling. Drilling tests were performed on bovine cortical bones at a drilling hole depth of 36 mm using a 2.5 mm diameter twist drill bit with a spindle speed of 3000 rpm and feed rates of 0.05, 0.075, and 0.1 mm/rev. Bone chips were collected at different depths and examined using a fiber-optic microscope. Not only are drilling forces a good indicator to assess drilling performances but also chip formation and morphology are important aspects for understanding bone-drilling behaviors. The force signals revealed two distinct states, which were referred to as normal and abnormal states in this study. In the normal state, the force signals remained constant once the drill tip became fully engaged in bone cutting, whereas after a certain drilling depth, the forces considerably increased in the abnormal state. The results of this study indicate that the rapid increase in the force in the abnormal state is mainly attributed to chip clogging inside the flutes as the drilling depth increases. This study also demonstrated that the chip morphology varies with respect to drilling depth, where fragmented chips are produced at shallow drilling depths and powdery chips are produced at deeper drilling depths.

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