Absorbable Stent for Reanastomosis of the Fallopian Tube

The primary goals of the Phase I research plan are to develop a prototype absorbable stent for use in mid-tubal reanastomosis and to evaluate the effectiveness of this device in a rabbit experimental model. Mechanical design criteria will be determined by making measurements of luminal caliber and tubal compliance in freshly excised rabbit oviducts. The stent will be designed to 1) accommodate disparate luminal sizes, 2) be easily inserted, 3) to resist longitudinal displacement once inserted, 4) be atraumatic to intraluminal mucosa, 5) facilitate anastomotic stitching, 6) allow normal flow of tubal fluid into the abdomen, and 7) be absorbed in approximately the time required for healing of the anastomosis. To meet this design criteria, the tubular stents will be fabricated out of polygycoloic acid (PGA). Prototype stents will be used to perform simulated reanastomosis in 20 rabbits after excision of the ampullo-isthmic junction. In each rabbit, the contralateral tube will be anastomosed by using standard microsurgical techniques and will serve as an internal control. Groups of five rabbits will be used to evaluate rate of healing and rate of absorption of the PGA stent at times ranging from one to 10 weeks after surgery. Stent effectiveness will be compared to that of standard microsurgical techniques in terms of duration of surgery, degree of abnormal morphology at the anastomotic site, and, in one group of five animals, restoration of fertility determined by the nidation index. Data on rate of healing and rate of PGA absorption will be analyzed by using regression analysis. Data on morphology and fertility will be analyzed by using a paired t-test to test for differences between the two anastomotic procedures.In Phase II we plan to develop additional devices to facilitate other varieties of tubal reconstruction, evaluate these new designs in experimental animal models, and test successful designs in clinical trials. Our overall goal is to provide devices that will improve the effectiveness and reduce the skill, time and cost of tubal reconstructive surgery, thereby contributing to overall improvement of female infertility therapy.