Study Of Implantation Mesh And Monofilament For Pelvic Floorfunctional Reconstruction

Pelvic floor disfunctional diseases seriously affect the women’s health and the quality of life. The main way to solve the problem is by implanting mesh to substitute damaged pelvic fascia tissue. A large number of researches reflect that the mesh applied to the female pelvic floor repairing shows a good effect. Recently, the meshes widely used are made of polypropylene monofilament.In this paper, we use PP, polylactic and nano pearl powder as raw materials. Three kinds of PP monofilaments with diameterO.lOmm,0.12mm,0.15mm respectively and one kind of PLA monofilament with a diameter of0.10mm were prepared by industrial equipment. The PP/pearl powder monofilaments were prepared by laboratory equipment. The main contents included in the dissertation are as follows.1.The processing parameter of monofilament was determined. In the process of preparing PP monofilaments, the spinning temperature was about270-285℃; the temperature of cooling bath was30℃;the first water drawing temperature should be between85℃and95℃; the second air drawing temperature was controlled to140-160℃; Stretching ratio was7. During the process of preparing PLA monofilaments, the spinning temperature was about210-220℃; the temperature of cooling bath was35℃; the first water drawing temperature should be between90℃and95℃; the second air drawing temperature was controlled to130℃; stretching ratio was5.5. The spinning temperature of PP/pearl powder monofilaments was260-265℃; water drawing temperature was90℃; thermosetting temperature was130℃;stretching ratio was3.2.2.The mechanical properties, sonic velocity, thermal shrinkage and cytotoxicity of monofilaments were investigated. The results showed that the tensile strength at break of three kinds of PP monofilaments exceeded5.0cN/dtex, the elongation at break was about20%, the mechanical properties of monofilament is equivalent to the import medical polypropylene monofilaments. In addition, the mechanical property of PLA monofilaments also met the requirement of medical monofilaments with tensile strength at break5.85cN/dtex, elongation at break21.4%. The thermal shrinkage ratio significantly increased when temperature rose from130℃to140℃. so the thennosetting temperature should not exceed130℃. The level of cytotoxicity of PP monofilaments was the same as imported PP monofilaments, toxicity ranging0-1. Compared to controlled group, the cytotoxicity ranging of PLA monofilaments reached2-3which needed further study to explain.3. The tensile strength at break of PP/pearl powder monofilament was3.8cN/dtex when the content of pearl powder increased from0%to2%. The elongation at break decreased from16.2%to13.8%and modulus showed a slight increase with the increase of pearl powder content. MTT test reflected that a certain content of pearl powder in PP monofilament could improve the cell activity and promote cell proliferation. Further more, with the increase of pearl powder content, cell proliferation showed a gradual increasing. Confocal fluorescence microscope photographs explained that the cytoplasm and nucleus of L-929cells cultivated by leaching solution from PP monofilaments containing pearl powder had clear boundaries, most of the cells emerged a health spindle shape. Thus the addition of pearl powder helped the proliferation of L-929cell.4.The pelvic mesh was made of the PP monofilament with0.10mm diameter and was knitted with warp knitting technology. Mesh thickness, surface density, porosity and the mechanical properties such as bursting strength, breaking strength, laddering-after-drawing strength and bending rigidity as well as thermal finalization parameters were discussed. More over, the cytotoxicity of mesh was also investigated by MTT. The results showed that when the stress was constant, the temperature and time had some impact on the basic properties of the pelvic mesh, and the temperature had more influence on the mechanical properties of the pelvic mesh than the time. When the time was constant, the breaking strength, bursting strength and laddering-after-drawing strength of the pelvic mesh decreased as the temperature increased but the rigidity and softness decreased The optimal heating setting temperature and time were130℃and15minutes. The mesh did not show any obvious cytotoxicity, the the cytotoxicity ranging of PP mesh was0.5.We adopted subcutaneous transplantation in mice inflammatory stress testing method to test the inflammation of homemade mesh. The result showed there was no obvious difference between the inflammation caused by homemade mesh and that of the controlled group.