Experiments And Simulation Studies On The Traction Damage Of Biological Soft Tissue By The Endoscopic Cutter Stapler

As the most commonly used cutting and suturing instrument in laparoscopic surgery,stapler has the advantages of simple operation,short surgery time,and fast postoperative recovery.However,due to the limitation of the operating space,the stability of the stapler in the abdominal cavity is heavily dependent on the doctor's proficiency and clinical operation experience.This may cause excessive movement range of instruments during the operation,resulting in unnecessary damage to healthy tissues,and then cause tissue damage,bleeding and various postoperative complications.In order to improve the safety of operation with stapler,it is necessary to study the interaction between stapler and soft tissue.At present,the staplers commonly used in clinical practice are divided into mechanical and electric staplers.The traditional mechanical stapler is driven by a mechanical structure,which requires a large firing force during cutting and suturing.Moreover,the mechanical stapler needs to work repeatedly to complete the cutting and suturing operation,which is easy to lead to the fatigue of the doctor's arm muscles,resulting in a wide range of irregular movements at the end of the stapler.The emergence of the electric stapler solves the disadvantage of the large firing force of the mechanical stapler.However,the electric stapler uses the motor to drive the blade movement,and the battery is needed to provide power for the motor,so the weight of the electric stapler is greater than that of the mechanical stapler.Nevertheless,excessive weight of the device itself may also cause irregular movement of the end of the stapler.Up to now,there are relatively few studies on the irregular movement of the ends during the use of staplers at domestic and overseas,and the study on the association between the movement of the ends of staplers and tissue injury is even blank.In this thesis,the relationship between the end movement and the tissue traction damage during the operation of the mechanical and electric endoscopic anastomat was systematically studied by experiment and simulation.The research contents of this thesis are as follows:Firstly,the code-controlled Realsense depth camera was used to identify the mark points,and the data set of the movement coordinates of the end markers during the operation of large intestine anastomosis using the stapler was collected,and the average distance between each point in the data set and the center point was used as the index to quantify the jitter degree.The difference analysis results of jitter degree between mechanical stapler and electric stapler showed that the jitter degree of the end of mechanical stapler was significantly higher than that of electric stapler during firing.Secondly,the s EMG signals of the subjects' right arm extensor carpi radialis,brachioradialis,flexor carpi radialis,biceps brachii were collected by using the DELSYS wireless s EMG signal acquisition system in the process of large intestine anastomosis using the stapler.The difference analysis results of right arm muscle EMG signals of subjects operating mechanical and electric stapler showed that the RMS value of arm muscle EMG signals during the firing process of mechanical stapler was significantly higher than that of electric stapler.According to the correlation analysis of EMG RMS value and jitter degree of the four muscles,the EMG RMS value of extensor carpi radialis,brachioradialis,flexor carpi radialis was significantly positively correlated with the jitter degree of the end of the anastomat.Thirdly,analysis of mechanical properties of the intestinal tissue,using the ANSYS finite element analysis software for simulation the process of clamping and tissue traction by stapler,observing the change of stress and strain under different traction angle,organizing the strain value of stress reaches 180 k Pa as displacement threshold of tissue traction damage,and combining with the jitter data collected in the experiment,different staplers were evaluated.The results showed that the higher the jitter frequency was during the use of mechanical and electric staplers,the higher the risk of tissue traction damage was.To a certain extent,the use of electric staplers could reduce the tissue traction damage caused by excessive firing force.In this study,the relationship between the jitter degree of the stapler and tissue traction damage was established,which provided a measurement method for evaluating the degree of tissue traction damage in the use of mechanical and electric staplers,provided a reference for the optimal design of electric staplers,and provided theoretical support for the improvement of clinical use standards of staplers.