การตรวจจับการเจาะทะลุกระดูกโดยอาศัยแบบจำลองการถดถอยเชิงเส้นแบบเวลาจริง

Abstract

Bone drilling is a significant surgical procedure. Many cases of bone drilling are critical, such as drilling the skull in brain surgery, drilling the spine for spinal cord treatment, etc. In bone surgery, drilling the bone without causing excessive protrusion and then causing severe damage to tissues is very important to reduce risk and ensure safety. Due to such requirements, this research aimed at studying drilling mechanics, which leads to the proposition of a breakthrough detection scheme for avoiding excessive protrusion. The research focused on the use of the most commonly used drilling tool, the twist drill bit equipped with an electrical drill, to perform bone drilling. A significant finding is that the current supplied to the motor driving the electrical drill has a relationship with the drilling torque load. When the breakthrough nearly occurs, the drilling torque load reduces, causing the motor current to reduce to zero. Detecting the breakthrough effectively relies on the combination of three key techniques: 1) the accurate measurement of the current supplied to the motor of the electric drill, 2) the effective control of stepwise drilling using a high-performance microcontroller, and 3) the use of ensemble linear regression models to verify the possible breakthrough. The measurement of current was performed by applying a sense resistor and a specially designed electronic circuit for signal conditioning. Based on stepwise drilling, changes in the current measurement signal could be clearly observed. By monitoring the signal peaks during drilling, the breakthrough could be identified since, in the breakthrough phase, the peaks declined successively to zero. When the breakthrough was detected, the drilling operation could be immediately terminated to prevent excessive protrusion that might cause damage to the surrounding tissues. Based on the experimental drilling tests that used a drilling system prototype, 10 times of acrylic plate drilling and 4 times of porcine bone drilling were performed, with successful breakthrough detection in all cases of these drilling tests. When the breakthrough was detected at each time of drilling, the drilling operation could be automatically terminated by the electronic control system.