The Research On Structure And Performance Of Knitted Biodegradable Chest Wall Prosthesis

Chest wall defects are always caused by the surgical excision of chest tumor,radiation ulcer,infection and congenital malformation as well as thoracic trauma. That is the reason why we need chest wall prosthesis to prevent mediastinum from swing and to avoid anomalous respiration. So far,we haven't found a kind of perfect material for chest wall reconstruction though a great many materials have been tested. But the biodegradable materials have rapidly promoted the development of chest reconstruction surgery as the decomposition products of them can be thoroughly absorbed and no harm to human body. In the meantime,they can significantly induce the regeneration of cells and tissues and overcome the drawbacks of the conventional materials.We introduced the material's performance,fabric structure and finishing so that we can find the optimum parameters to meet the physiological requirements of chest wall prosthesis.Firstly,we introduced some common synthetic biodegradable materials and the drawbacks of materials if they were used as the chest wall prosthesis. We pointed out that the PDS (polydioxanone) was the very appropriate material for the chest wall prosthesis and described its structure and performance. Then we studied the properties,such as the retention weight,the PH value of phosphate buffer solution,crystallinity,the retention of tensile strength and morphological changes,which were changing during the hydrolytic degradation of polydioxan- one.Secondly,it is very important that an appropriate structure must be hard to run. We selected three types of warp-knitting:atlas tricot stitch,tricot stitch based on rib and tricot stitch based on interlock. On the base of orthogonal test,comparing the tensile strength,bursting strength,flexural length,suture retention strength and porosity,the optimum parameters of fabric structure,coating and knitting density could be selected. In orthogonal test,the optimum technical parameters were coating with 3.0% chitosan,tightness knitting density and tricot stitch based on interlock.Thirdly,the chest wall prosthesis was treated by heat setting. In orthogonal test, the optimum parameters of heat setting were obtained through quadratic general rotary unitized design as follows:the temperature was 85.9℃,the time was 4.2min.Finally,the animal model of the chest wall reconstruction was established to evaluate the chest wall prosthesis. Chest wall stability,the process of degradation of the prosthetic material and regeneration of the chest wall tissue post operatively was recorded dynamically by microscopy so as to provide valuable scientific data for the improvement of chest wall prosthesis. The results of the biodegradable polydioxanone prosthesis investigation showed their excellent biocompatibility and bioactive properties. They fulfilled the function in providing chest wall stabilization and had a favorable profile in chest wall reconstruction,for which they were very promising for clinical application.