Research On Handheld Instruments For Minimally Invasive Surgery

The operation process of minimally invasive surgery is to first cut a small wound on the patient’s body surface,insert a poke card,and inflate it to form a pneumoperitoneum.At the same time,the surgical assistant operates the endoscope,and the endoscope also enters the patient’s body through other poking holes to provide the surgeon with an internal spatial view.This surgical method requires a good tacit understanding between the doctor and the assistant,and long-term operation is prone to fatigue,and the operating tools between the doctor and the assistant may collide and interfere,which will affect the quality of the operation.In order to reduce this negative effect and improve the comfort of the surgeon when using the device,it is very important to develop a set of hand-held devices with good performance.In this paper,through the analysis of wire transmission and traditional instruments,the function and structure of the current hand-held instruments are improved,and experiments such as functional verification,fatigue testing,and simulated surgery are carried out.The specific research contents are as follows:1.Research on hand-held rigid instruments for minimally invasive surgery: A set of new multi-degree-of-freedom hand-held instruments for minimally invasive surgery was designed by using the principle of bionics and simulating the swing characteristics of human wrists.Based on the configuration of traditional surgical instruments,the instrument introduces the wrist structure and uses steel wire transmission to enable the end effector to have a deflection function.At the same time,a pin gear structure is added to the operating end,so that the instrument can lock its posture after deflecting at a certain angle.It has a deflection self-locking function and can keep the deflection posture unchanged under certain external force interference.Through the rational design of the direction of the steel wire and the guide wheel,the kinematic coupling problem existing in general multi-degree-of-freedom surgical instruments is basically solved.Through the optimization of the structural details and the study of the wire rope fixing problem,the problems of rope length change and unsightly appearance caused by the knotting and fixing of the wire-driven surgical instruments in the past have been effectively solved.At the same time,static simulation checks were carried out on key components.2.Research on handheld flexible instruments for minimally invasive surgery: The instrument introduces a multi-joint flexible deflection structure into the traditional hand-held instrument,so that the end effector has a larger deflection range and can complete surgical actions in a larger working space.The self-locking of the flexible yaw part adopts the spring pin mechanism,and through the reasonable design of the wire direction and the guide wheel,the kinematic coupling problem is avoided,and the static stress and strain simulation analysis of the key parts is done.In addition,the development of multi-degree-of-freedom rigid electrocoagulation,flexible electrocoagulation,and flexible electric knife was carried out,and finally the serial design of the small claws at the end of the instrument was carried out.3.Experimental bench design and instrument fatigue test: In this chapter,through the analysis and research of the equipment assembly process,fatigue experiment,clamping force measurement experiment,etc.,the steel wire rope pre-tightening force loading device in the equipment assembly,the equipment fatigue test system,and the selection and calibration of the sensor for measuring the clamping force are respectively designed..In addition,a small device for the riveting of the yaw joint of the flexible instrument is designed,which can clamp and fix the two riveted joints to prevent the joint rotation from affecting the assembly during riveting.And the above devices are integrated into a test bench,and a multi-functional test bench that can be assembled and tested is completed,and the fatigue test of the device developed in this paper is carried out.4.In order to determine whether the performance and function of the device designed in this paper meet the design requirements.A variety of experiments were designed to test it: the bearing capacity test of hand-held rigid instruments and flexible instruments,the flexibility test of picking objects across obstacles and the retention of clamping force;the design of hand-held electrocoagulation and electric knife The coagulation and electric cutting effect tests were carried out;finally,the minimally invasive surgery simulation experiment was completed using the hand-held passive and active instruments developed in this paper.