Synthetic suburethral slings have recently become popular despite the risk of erosion commonly associated with synthetic implants. Some of these materials seem to have unexpectedly low erosion rates. Based on the hypothesis that erosion is due, in part, to biomechanical properties, we undertook an in vitro study. The biomechanical properties of eight non-resorbable synthetic implant materials, stiffness (slope, N/mm) and peak load (N) were determined from load vs. displacement curves. Open-weave Prolene mesh showed unique biomechanical properties compared to other tested materials. The tension- free vaginal tape had the lowest initial stiffness (0.23 N/mm), i.e. low resistance to deformation at forces below the elastic limit, whereas the stiffest implant tested, a nylon tape, reached 6.83 N/mm. We concluded that the TVT and other wide-weave Prolene tapes have unique biomechanical characteristics. These properties may be at least partly responsible for the apparent clinical success of the implants.
Keywords Biomechanics - Implant materials - Incontinence surgery - Prolene mesh - Stiffness - TVT
Editorial Comment: Understanding the biomechanical properties of synthetic meshes is important in choosing appropriate materials for a variety of urogynecologic procedures, particularly suburethral slings. Although this paper does not address histologic or in vivo findings, the biomechanical properties that seem to be important are mesh pore size, weave and stiffness. Although mesh may be made from similar materials, the final weave of the product may play a role in the ultimate outcomes or complications from slings. Further studies in animal or human models may be necessary to determine the importance of these biomechanical properties.