Research On Key Technologies Of Surgical Instruments For Robot-assisted Minimally Invasive Surgery

Compared with the traditional open surgery,the minimally invasive surgery(MIS)has obvious advantages,such as small incision,less bleeding,and rapid recovery.With the development of science and technology,robot-assisted minimally invasive surgery(RMIS),which combines robot technology with MIS,liberates doctors from the operating table,and even implements remote surgical treatment.Robot surgery systems generally include master-slave control system,imaging system and robotic arm system.End-effector is one of the core parts of the robotic arm system.Usually,doctors are used to refer to the end-effector as surgical instruments.As the executive mechanism of surgery,it is used to complete the operation of cutting,clamping,suturing,lifting and dissociating the organs and tissues.The performance of surgical instruments directly affects the quality of the operation.It is one of the most important parts of the robot surgical system.In this paper,according to the characteristics of the RMIS,a variety of surgical instruments have been developed for various types of robotic surgery.First,for the porous laparoscopic robotic surgical system that has entered clinical application,the coupling phenomenon of the wrist joint of the surgical instruments during the operation of the robot operation system is analyzed.Then,a new mechanical decoupling mechanism is designed and applied to the developed equipment four degrees of freedom uncoupled fast changing surgical instruments with wrist joint motion.Finally,a series of experiments verified the functional and excellent decoupling effect of the designed surgical instruments.Secondly,on the basis of rigid surgical instruments used in robotic surgery system,a snake-like surgical instrument using a series of flexible micro-joints is designed.The surgical instrument has a long flexible part,which can adjust the posture of the surgical instrument in the patient's body depending on its own bending and rotation,eliminating the remote center mechanism and a plurality of adjusting joints on the mechanical arm,greatly saving the space of the operating table,and fundamentally avoiding the safety hazard of collision between multiple mechanical arms.The forward and inverse kinematics equations of snake-shaped surgical instruments are obtained by a discrete method,and the accuracy of the equations is verified.Through a series of experiments,the performance of the designed surgical instruments was verified.The performance improvement of surgical instruments can even affect the way of MIS,such as the current cutting-edge Single Port Laparoscopy(SPL)and Natural Orifice Transluminial Endoscopic Surgery(NOTES).On the basis of rigid surgical instruments and snake-like surgical instruments,this paper innovatively combines the flexible multi-joint structure with the joint expansion structure,to design the surgical instruments for SPL.The surgical instruments with a diameter of only 28 mm can deform in the patient's body with a pair of flexible surgical instruments and an endoscope.Besides,with the use of rotation and linear motion of the expanding joint of surgical instruments,as well as the flexible joint movement of the surgical instrument,the surgical operation in a large working space can be achieved.In addition,the designed SPL platform can be applied to NOTES after some technical modifications.Finally,for the selection of surgical incision in preoperative preparation,this paper proposes a method combining the requirements of the operation and the characteristics of the robot system,and the optimal surgical incision was analyzed with cholecystectomy as an example.Using the operating vehicle developed by the project team and the new remote center mechanism as the carrying platform of the surgical instruments,the rigid surgical scissors and flexible surgical forceps designed in this paper are installed in the operating vehicle,a RMIS manipulator system is formed.We selected the chicken heart and the pig liver to carry out the operation experiment of the isolated animal organ,and successfully completed the operation experiment with the robotic arm system,and verified the effectiveness of the surgical instruments and reliability.Through the medical surgical instrument simulation exercise tool,the SPL platform developed by the experiment of small ball extraction,serpentine perforation and suture operation,the feasibility of the SPL platform was proved.