Designing pre-tensioned core-shell fibers to treat pelvic floor disorders

Here we relate support provided to the pelvic floor by composite fibers having pre-tensioned cores secured by thin shells to tunable fiber properties. Surgical treatment of pelvic floor disorders including stress urinary incontinence and pelvic organ prolapse often inserts polymeric mesh to support pelvic fascia. However, achieving optimal levels of mesh tension and organ lift in minimally invasive surgeries remains challenging. Fibers with pre-tensioned cores and biodegradable shells have the potential to overcome this challenge by allowing reconstructive surgeons to "dial in" specific amounts of support without over tensioning mesh slings, which may lead to soft tissue erosion and voiding dysfunction. Consequently, this study quantifies the relationship between fiber dimensions and properties with the lift these fibers (once integrated into mesh) can provide to pelvic organs. Our linear elastic model quantifies the minimum and maximum amount of pre-tensioning allowed from tissue lift and core-shell delamination considerations, respectively. The model indicates that the elastic modulus of the biodegradable shell polymer should be orders of magnitude larger than that of the core polymer and be at least 10% of the core radius to preserve tension within the core that subsequently translates into tissue support.