Analysis of Forces during Robotic Needle Insertion to Human Vertebra

The purpose of this study is assessment of forces and torques required for robotic needle insertion to human vertebra. Axial forces during robotic insertion to human vertebrae fixed with formalin (water solution of formaldehyde(FA)) did not exceed 25 N when the feed rate was no more than 0.5 mm/s. There was relatively strong correlation between the axial force variation during insertion and the distribution of bone local CT-value along the needle path. This result shows the importance of preoperative X-ray CT image guidance for robotic needle insertion with safely small axial forces. There was no significant influence of FA-fixation on axial forces during robotic needle insertion to human femoral heads. The forces during robotic insertion to human femoral head were as small as less than 50% of those during manual insertion, and which indicates that the robot can contribute to the safe needle insertion to human vertebra in percutaneous vertebroplasty.