Development And Testing Of Intelligent And Minimally Invasive Surgical Robot System For Fracture Of Femoral Shaft

Part I Development and testing of reduction robot for fracture of femoral shaftObjective: To develop anintelligent reduction robot system for intelligent reduction of fracture of femoral shaft, and to test the accuracy of reduction, based on clinical environment of closed reduction intramedullary nailing surgery in fracture of femoral shaft.Methods:We developed a parallel-serial reduction robot system which was based on Stewart platform. The 2-dimension navigation system was based on X-ray and registration strategy of mirror symmetry of bilateral femoral. We performed reduction test on 12 femoral models and 2 cadavers and then we tested its resetting accuracy of reduction robot based on long bone fractures analysis of robot.Results:Femoral models test using reduction robot system showed that residual resetting accuracy was 1.67±0.78mm for axial displacement with rotation angle of 2.08±0.67°,and 1.33±0.56mm for lateral displacement with varus-valgus rotation angle of 1.50±0.56°.Cadaver test using reduction robot system showed that residual resetting accuracy was 3.08±1.50mm for axial displacement with rotation angle of 2.58±1.24°,and 1.92±0.61mm for lateral displacement with varus-valgus rotation angle of 1.98±0.620°.Conclusion: The reduction robot system showed high reduction accuracy and reduction result, which provided an intelligent, precise and minimally invasive method in clinical treatment of fracture of femoral shaft.Part II Development and testing of target positioned robotObjective: To develop a target positioned robot system assisted in femoral intramedullary nailing distal interlocking screw placement in view of higher intraoperative radiation and poor accuracy in traditional insertion procedure, and analyze its advantages over traditional way.Methods:We developed a target positioned robot system based on Universal Robots arm.The 2-dimension navigation system was based on X-ray. From January 2016 to December 2016, 6 femoral shaft fracture patients treated by intramedullary nailing distal interlocking screw placement assisted by target positioned robot computer were reviewed . The control group involved 26 femoral shaft fracture patients who had undergone traditional surgery with closed reduction by intramedullary nailing distal interlocking screw placement in the same period.There was no significance in gender, age, side of fracture and types of fracture between these two groups (P>0.05). The data of operation time, intraoperative frequency of fluoroscopy and one-time successful screw placement rate (without repeated drilling),and the angle of two distal screw shown in postoperative frontal X-ray film between these two groups were collected and compared, and analyze advantages of target positioned robot.Results:The robot-assisted group needed a much longer operation time compared with control group (13.17±4.54min VS 7.96±1.07min, t=2.795, P=0.037), however the robot-assisted group had less intraoperative frequency of fluoroscopy (5.83±2.04 VS 28.69±8.41, t=-6.537, P<0.001), and the angle between two distal screw was smaller in robot group compared with control group (0.35±0.89° VS 3.12±2.75°, U=9.00, P=0.001).In addition, the one-time successful screw placement rate was significantly higher compared with control group (100% VS 73%, X2=4.135, P=0.042).Conclusion:Target positioned robot-assisted femoral intramedullary nailing distal interlocking screw placement showed great advantage than traditional freehand technique during routine clinical surgery, including decreasing intraoperative radiation and surgical trauma during operation, as well as improve accuracy of surgery.