Effect of Surgical Drill-Bit Geometry in Deep-Hole Bone Drilling

Poster Number

12

Lead Author Major

Mechanical Engineering

Lead Author Status

5th year Senior

Format

Poster Presentation

Faculty Mentor Name

Dr. JuEun Lee

Faculty Mentor Department

Mechanical Engineering

Abstract/Artist Statement

Deep-hole bone drilling refers to bone drilling processes where drilling depths are greater than ten times the drill-bit diameter. Many surgical procedures, due to a high drilling depth to drill-bit diameter ratio, can lead to undesirable mechanical/thermal damage. A previous study observed completely different behavior in deep-hole bone drilling compared to shallower drilling depths. Force signals during deep-hole bone drilling showed an abnormal trend with abrupt increases after a certain drilling depth, attributed to chip jamming inside the drill-bit flutes. This considerable force increase can cause several complications, such as bone-cell death by increasing heat generation and drill-bit breakage. Hence, it is critical to resolve these current force issues in deep-hole bone drilling. This study aims to investigate how different types of drill-bit influence the deep-hole bone drilling forces. Two different types of drill-bits were selected: parabolic drill-bits which have a constant flute area along the drill-bit body, and conventional twist drill-bits, where the flute areas decrease toward the shank of the drill-bit. Both drill-bit types were of 2.5mm diameter, commonly used in many surgeries. A series of drilling tests were conducted on a computer numerically controlled machine and bovine cortical bones were used as bone samples. To evaluate bone drilling performance from the different drill-bit types, forces and temperature signals were measured over drilling depth using a dynamometer and infrared thermal camera, respectively. The results indicate that maximum thrust force and torque values considerably decreased with parabolic drill-bits, showing more constant force trends, while conventional twist drill-bits showed abnormal force trends after a certain drilling depth. Increasing measured forces directly related to temperature increases, and this study observed considerably higher maximum temperatures using conventional twist drill-bits. The findings of this study can be a strong foundation to provide solutions to current deep-hole bone drilling, leading to successful surgical outcomes.

Location

University of the Pacific, 3601 Pacific Ave., Stockton, CA 95211

Start Date

24-4-2021 1:00 PM

End Date

24-4-2021 2:15 PM

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Apr 24th, 1:00 PM Apr 24th, 2:15 PM

Effect of Surgical Drill-Bit Geometry in Deep-Hole Bone Drilling

University of the Pacific, 3601 Pacific Ave., Stockton, CA 95211

Deep-hole bone drilling refers to bone drilling processes where drilling depths are greater than ten times the drill-bit diameter. Many surgical procedures, due to a high drilling depth to drill-bit diameter ratio, can lead to undesirable mechanical/thermal damage. A previous study observed completely different behavior in deep-hole bone drilling compared to shallower drilling depths. Force signals during deep-hole bone drilling showed an abnormal trend with abrupt increases after a certain drilling depth, attributed to chip jamming inside the drill-bit flutes. This considerable force increase can cause several complications, such as bone-cell death by increasing heat generation and drill-bit breakage. Hence, it is critical to resolve these current force issues in deep-hole bone drilling. This study aims to investigate how different types of drill-bit influence the deep-hole bone drilling forces. Two different types of drill-bits were selected: parabolic drill-bits which have a constant flute area along the drill-bit body, and conventional twist drill-bits, where the flute areas decrease toward the shank of the drill-bit. Both drill-bit types were of 2.5mm diameter, commonly used in many surgeries. A series of drilling tests were conducted on a computer numerically controlled machine and bovine cortical bones were used as bone samples. To evaluate bone drilling performance from the different drill-bit types, forces and temperature signals were measured over drilling depth using a dynamometer and infrared thermal camera, respectively. The results indicate that maximum thrust force and torque values considerably decreased with parabolic drill-bits, showing more constant force trends, while conventional twist drill-bits showed abnormal force trends after a certain drilling depth. Increasing measured forces directly related to temperature increases, and this study observed considerably higher maximum temperatures using conventional twist drill-bits. The findings of this study can be a strong foundation to provide solutions to current deep-hole bone drilling, leading to successful surgical outcomes.