Computer Modeling of Biomechanical Response of Synthetic Meshes for the Repair of Pelvic Organ Prolapse (pop)

INTRODUCTION Pelvic Organ Prolapse (POP) is a debilitating and common disease that affects women’s quality of life. In a 1997 regional study, 11.1% of all women had the risk of undergoing a POP repair surgery [1]. Most women patients that undergo POP repair are >= 52 years of age and have previously had a hysterectomy. Part of the POP repair problem is that reoperation rates are 30% [2]. This common reoperation rate of POP repair and even POP is still today not fully understood but thought to be caused by tissue-mesh interaction and failure of supportive tissue respectively. Women patients who experience POP symptoms are extreme enough to consider surgery have many treatment options that include observation, conservative treatments, and surgery [3]. There are also different types of surgeries that repair POP one of which is transvaginal mesh procedures that come as prepackaged kits that create a hammock that supports the pelvic organs by attaching a mesh to the pelvis and or sacral ligaments [3]. The purpose of transvaginal mesh kits was to decrease recurrent prolapse and avoid intra-abdominal surgery [3]. However in 2011, the FDA issued a statement that “Based on evaluation of adverse event reports and assessment of the scientific literature, the FDA has NOT seen conclusive evidence that using transvaginally placed mesh in POP repair improves clinical outcomes and more than traditional POP repair that does not use mesh, and it may expose patients to greater risk” [4]. One of the most serious negative outcome of POP repair noted by the FDA, is vaginal mesh erosion that requires multiple surgeries to repair and a pain that lasts even after removal of mesh [4]. Research at the University of Pittsburgh has been done to study the differences in transvaginal mesh kits available for surgery to suggest that there may be a connection between the different geometry, material properties, and surgical placement of the mesh kits and their associated failure rates. In other words while the FDA assumes all mesh kits are unsafe, further research and understanding of the vastly different mesh kits could lead to a recommendation on the type of geometry, material, and surgery technique to use to improve clinical outcomes. In this research it was hypothesized that a highly detailed structure of the arguably most important organ in terms of studying POP was the vagina. In building a model that had a highly detailed structure of the vagina and the connections the vagina has to its supportive anatomical structure represented as a set of boundary conditions put on the model, a finite element analysis could be run on the nodes and elements that make up the vagina under realistic boundary conditions to simulate stresses in the vagina caused by POP and POP repair using transvaginal mesh. Objective To design and build a model of the women's pelvic floor so that we could better understand the causes of pelvic organ prolapse and evaluate the treatment option of transvaginal mesh using finite element analysis.