Motion Planning and Long-term Robot Monitoring Perspective: A Cadaver Study on Robot-Assisted Pedicle Screw Fixation

Pedicle screw instrumentation is a common proce-dure for treating spinal deformities. Despite its prevalence, the conventional free-hand techniques for pedicle screw insertion have shown a notable rate of malpositioning leading to severe complications. Robotic systems have emerged as promising solutions to enhance the accuracy of pedicle screw instrumentation. But, they often come with high costs, and long-term robot moni-toring remains a challenge. The paper discusses the development and evaluation of a robot-guided pedicle screw instrumentation system using a collaborative manipulator. It presents a novel motion planner for generating collision-free robot motions and proposes a self-reliant, cost-effective evaluation strategy for long-term robot monitoring. The proposed evaluation strategy showed an accuracy estimate of 0.71 mm with a standard deviation of 0.34 mm. The accuracy estimate and the motion planning capability measure, obtained using the proposed evaluation strategy were investigated in a cadaver study. 10 screws were instrumented on both sides of the L4, L3, L2, Ll, and T12 vertebrae to assess the accuracy and performance of the proposed system. All screw fixations fell under the Grade 0 breach category when subjected to Gertzbein and Robbins classification. The cadaver study showed the scope for utilizing collaborative manipulators in pedicle screw instrumentation. The motion planner was able to generate collision-free tool paths for all the input screw plans. The results obtained through the cadaver study showed that the proposed evaluation strategy gives a conservative estimate of the system's accuracy.