Feasibility And Biocompatibility Research Of Newly Designed Ureteral Stent And Magnetic Catheter

Purpose: Ureteral stent was used to facilitate the kidney drainage. It was alwaysremoved by cytoscope which is a invasive operation can cause some complication as bleedingor infection and so on. The biodegradable ureteral stent was reported to solve this problem,but the degradation time of biodegradable ureteral stent could not be change to adapt thedemands of clinical, and it also has problem with biocompatibility. A minimally invasivemethod does not require cystoscopy or fluoroscopic guidance for ureteral stent removal issignificative. So we developed the first generation newly designed “a ureteral stent with self-release processed polyester sutures and the magnetic incarceration catheter”and the secondgeneration newly designed “a ureteral stent with self-release processed polyester web and themagnetic web-capture catheter”. The characteristic of materials were tested to determine thereliability of the two newly designed ureteral stent. The biocompatibility were tested todetermine the security of the two newly designed ureteral stent. Estimate the feasibility ofthem through a competitive experiment in the transparent ureteral tract model A preliminaryobservation of the two newly designed ureteral stent by extracorporal remove experiment.Materials and Methods: We developed the first generation newly designed “a ureteralstent with self-release processed polyester sutures and the magnetic incarceration catheter”andthe second generation newly designed “a ureteral stent with self-release processed polyesterweb and the magnetic web-capture catheter”. Features of the Ureteral Stent and MagneticRetrieval Catheter： The content of ferric oxide powders coated on processed polyestersutures was analyzed by a thermogravimetric analyzer. The mechanical drafting-stretchingproperties of the surgical polyester sutures were determined by a force testing machine. Themagnetization value of the magnetic retrieval catheter was measured by a magnetometer.Dissolution times of soluble packing material was tested in saline. Randomly select21SDrats. the processed polyester sutures were embedding into the back muscle fo the rat, put3ratinto death and take muscle sample after1、2、3、4、6、8、12weeks, observe the muscle pathological section. Estimate the feasibility of newly designed ureteral stent in a TransparentUrinary System Mode.Results: The first generation newly designed “a ureteral stent with self-release processedpolyester sutures and the magnetic incarceration catheter”and the second generation newlydesigned “a ureteral stent with self-release processed polyester web and the magnetic web-capture catheter”were manufactured. Features of the Ureteral Stent and Magnetic RetrievalCatheter：The maximum elongation ratio of the processed polyester sutures was23.75%±0.27%. The breaking strength and Young’s modulus of the processed polyester sutures were10.12N/tex. The magnetization value of the magnetic retrieval catheter was578emu/g. Thedissolution times of soluble packing material was24±0.37h. Pathological section:inflammatory cells and fibroblast could be seen around the back muscle tissue of rat byoptical microscope in the first3weeks, the inflammation was alleviate from4th week. Theinflammation disappeared in the12th week. Both of the two newly designed ureteral stentcould be removed from the transplant urinary system model.Conclusions: Both of the first generation newly designed “a ureteral stent with self-release processed polyester sutures and the magnetic incarceration catheter”and the secondgeneration newly designed “a ureteral stent with self-release processed polyester web and themagnetic web-capture catheter”could be manufactured by existing method. The feature of thetwo newly designed ureteral stent and magnetic catheter meets the demand. PVA was theoptimal packing materia, the processed polyester sutures and the processed polyester webcould be released in saline. The processed polyester sutures cause mild tissue damage, thebiocompatibility was similar to tradition ureteral stent. the two newly designed ureteral stentcould be removed from the transparent urinary system model. The velocity of attraction andcapture were fast. this minimally invasive method does not require cystoscopy or fluoroscopicguidance for ureteral stent removal is simply and effective.