Are biomechanical properties predictive of the success of prostheses used in stress urinary incontinence and pelvic organ prolapse? A systematic review.

AIMS: Progressive weakness in pelvic floor tissues is extremely common and leads to the distressing problems of stress urinary incontinence (SUI) and pelvic organ prolapse (POP). There has been extensive work on a vast array of materials spanning synthetics, autografts, allografts, and xenografts. Uniaxial testing of materials has been used to predict their success and rates of erosion. We aimed to compare the uniaxial properties of prostheses to native paravaginal tissue and correlate these to their success and erosion rates.
METHODS: We performed a systematic review of the literature to identify the biomechanical properties of paravaginal tissue and of prostheses used in the treatment of SUI and POP. We examined to what extent these findings correlated to their reported success and erosion rates.
RESULTS: Biomechanical properties have been determined for prostheses used in the treatment of POP and SUI both pre- and post-implantation in animal models. Implantation generally led to a decrease in ultimate tensile strength and Young's modulus. We were unable to find any simple correlation between the uniaxial mechanical properties of materials and their success or erosion rates.
CONCLUSIONS: Mechanical properties of prostheses, as measured by uniaxial testing, only appears to form part of the picture. We suggest implant integration and host responses to materials, as well as the biomechanical properties of the materials need to be considered to design materials to achieve lasting clinical benefit.