Resorbable, Shape Memory Stents to Prevent Vaginal Fibrosis

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RESORBABLE, SHAPE MEMORY STENTS TO PREVENT VAGINAL FIBROSIS Nearly 50,000 female adolescent patients undergo vaginal reconstruction each year, and approximately 73% of these patients will suffer from debilitating vaginal fibrosis following surgery. Pediatric and adolescent gynecologic surgeons often use vaginal stents in the immediate postoperative setting to facilitate wound healing. Unfortunately, the only available vaginal stents on the market are large, non-ergonomic designs that are poorly tolerated in the pediatric population. Indeed, these stents only recently became available again after being removed from production for more than 5 years. As a result, many surgeons have resorted to make-shift devices created in the operating room. All of these options present deployment challenges, limited sizing options, and poor retention, which frequently requires suturing of the vagina to prevent egress. There is a critical need for a new pediatric/adolescent-specific vaginal stent with appropriate sizing that can apply constant pressure to the boundaries of the neovagina to prevent fibrosis and maintain vaginal caliber during wound healing. Key design features will include easy insertion with improved ergonomics, prevention of egress with Valsalva, and ultimately prevention of fibrosis and improved vaginal healing. In addition, the development of new resorbable vaginal stents would offer additional advantages by eliminating the need for postoperative stent removal after wear-time is complete. In the design of a resorbable vaginal stent, it is necessary to balance mechanical properties such that the stent maintains vaginal patency (e.g., sufficient radial strength) while avoiding adverse biological responses, such as tissue overgrowth, and ensuring sufficient flexibility for patient comfort. Our objective is to design a resorbable, shape-memory vaginal stent that can improve clinical outcomes and quality of life for pediatric and adolescent patients following vaginal surgery. Our proposed design utilizes a shape- memory foam that is biodegradable and can assume a secondary, compressed shape for ease of deployment. Upon insertion, the change in temperature and hydration will initiate the expansion of the foam to shape fit to the individual patient and restore the lumen of the stent to allow egress of vaginal secretions. Uniquely, this circumvents the need for an external balloon to inflate the stent, a strategy common to current designs that causes challenges during clinical deployment. In addition to the tunable polymer chemistry, the porous architecture allows for multiple methods to optimize the mechanical properties, shape recovery, and resorption kinetics. In the proposed studies, we will fabricate and test the deployment and retention of this newvaginal stent design in a benchtop model followed by assessment in a rabbit model. A pediatric vaginal stent is long overdue and this study is unique in its design to meet the needs of this underserved population. This versatile design can also be tailored for adult patients with post radiation vaginal stenosis due to gynecologic and colorectal cancer treatment.