Surgical treatment of vaginal vault prolapse using different prosthetic mesh implants: a finite element analysis

Abstract

Particularly multiparous elderly women may suffer from vaginal vault prolapse after hysterectomy due to weak support from lax apical ligaments. A decreased amount of estrogen and progesterone in older age is assumed to remodel the collagen thereby reducing tissue stiffness. Sacrocolpopexy is either performed as open or laparoscopic surgery using prosthetic mesh implants to substitute lax ligaments. Y-shaped mesh models (DynaMesh, Gynemesh, and Ultrapro) are implanted in a 3D female pelvic floor finite element model in the extraperitoneal space from the vaginal cuff to the first sacral (S1) bone below promontory. Numerical simulations are conducted during Valsalva maneuver with weakened tissues modeled by reduced tissue stiffness. Tissues are modeled as incompressible, isotropic hyperelastic materials whereas the meshes are modeled either as orthotropic linear elastic or as isotropic hyperlastic materials. The positions of the vaginal cuff and the bladder base are calculated from the pubococcygeal line for female pelvic floor at rest, for prolapse and after repair using the three meshes. Due to mesh mechanics and mesh pore deformation along the loaded direction, the DynaMesh with regular rectangular mesh pores is found to provide better mechanical support to the organs than the Gynemesh and the Ultrapro with irregular hexagonal mesh pores.

The use of polymeric meshes for pelvic organ prolapse: Current concepts, challenges, and future perspectives

“…This can be represented through animal models, although this involves significant approximations and limits the ability to represent different pathologies related to POP (Gomelsky & Dmochowski, 2007;Rubod et al, 2012). An increasingly popular alternative is provided through computational finite element modeling (Todros et al, 2015), which provides a potentially powerful tool to investigate dynamic loading and patient specific anatomy in POP (Chen et al, 2015) and to examine the response of different types of mesh implant (Bhattarai, Jabbari, Anding, & Staat, 2018).…”

“…Design requirements emerging from recent research include a need for anisotropic meshes with properties tailored and matched to the contacting soft tissues at its surface, features which could be realized using techniques such as electrospinning (Roman, Mangir, et al, ). Mechanical characteristics are also highly relevant to surgical application, and further work is required to improve our understanding of how meshes will respond when implanted to ensure they avoid failure (e.g., mechanical biocompatibility) and remain effective in supporting the pelvic floor long‐term (Bhattarai et al, ).…”

A finite element analysis of different postures and intra-abdominal pressures for the uterine ligaments in maintaining the normal position of uterus

“…Liu et al 17 established a finite element model of the whole pelvic support system (including the uterus, vagina with cavity, CL and USL, levator ani muscle, rectum, bladder, perineal body, pelvis, and obturator internus and coccygeal muscles), the relationship between high IAP and the compliance of the pelvic floor support system in a normal woman without pelvic organ prolapse (POP) was studied on the basis. Gordon et al 18 and Bhattarai et al 19 established the finite element models of vaginal wall and its supporting tissue, the vaginal prolapse was studied on the basis. Moreover, some scholars used FEA to study the effect of mesh anchoring technique (simple stich and continuous stitch) and the behavior of implants used to replace damaged apical ligaments, such as USL and CL 20 , 21 .…”