The Research Of Biliary-enteric Biomechanic And Magnetic Compression Anastomat Structural Designment

Anastomosis technology of hollow viscera is considered as fundamental in the treatment of various hepatobiliary and intestinal diseases.Magnetic compression anastomosis has been paid attention for the little damage,simplity and easy operation.It can be operated with the help of laparoscopic and endoscopic.But the magnetic compression anastomosis for different organizations requires different pressures to reconstruct which is the key factor to the success of anastomotic reconstruction. As for the biliary-enteric magnetic anastomosis,the force of the magnet is too small to complete the anastomosis for biliary tissue’s narrow,and at present the design of the magnet and its size mainly depend on physician experience.To solve these problems, this study researched the range of the appropriate press for biliary-enteric anastomosis and design magnet structural parameters of biliary-enteric tissue.To study the relationship betwween force and structures and magnetic parameters,Different structures of magnetic were designed and its appropriate magnetic force were provided for surgeons to choose.Magnetic structures and parameters can affect the magnetic force, by experimental measurement and software calculation, it is concluded that the two same cylindrical magnet, with the increase of diameter at the same time,the magnetic force will get increase ranging from 30.5% to 50.2% per mm,while the magnetic force has a little increase with the height increasing and the biggest increase was 8.7% per mm;The force of two different diameter magnets with same height, increase one of the diameter of the magnet,the attenuation of magnetic force with distance betwween the magnets will decrease.Magnetic structure was designed with a resin and metal shell and analysed its press for biliary-enteric anastomosis. The normal biliary tissue mechanical properties were measured under the stretched condition to obtain elastic modulus 0.445 MPa. Use ansys workbench to simulated biliary-enteric anastomosis which was pressed by different pressure, to view the deformation and stress of intestinal and bile. The results show that:there were some stress concentration on the bile tissue and it occur in the outer edge of the shell.The healing process of bilioenteric tissue under magnetic press were studied to explore the optimum stress. Four group of different magnetic stress in biliary-entericexperiments were operated. HE & Masson staining results and burst pressure test results show that the best appropriate magnetic stress of bilioenteric is range from 0.2MPa to0.3MPa, suitable anastomosis force is range from 4N to 8N. The compressive stress in a suitable range, the greater the magnetic force, the magnet leave the anastomosis faster and the speeding of the tissue necrosis and the speed of the stoma’s growing is in same pace.