On the relevance of uniaxial tensile testing of urogynecological prostheses: the effect of displacement rate.

INTRODUCTION AND HYPOTHESIS: Uniaxial tensile testing is commonly used to calculate values of mechanical properties of urogynecological prostheses used in stress urinary incontinence and pelvic organ prolapse surgery in women. Clinical behavior of these products has been linked to their mechanical properties, hence influencing the clinician's preference for one brand or another. The objective of this study is to assess the effect of displacement rate used in uniaxial tensile testing on peak load, extension at peak load, and initial stiffness of Prolene® mesh, used as a proxy for urogynecological prostheses.
METHODS: Strips of Prolene® mesh measuring 10 × 30 mm were submitted to uniaxial tensile testing at the following rates: 1, 10, 50, 100, and 500 mm/min. Peak load, elongation at peak load, and initial stiffness were computed from load vs displacement curves at all displacement rates. The effect of displacement rate on these parameters was estimated by fitting linear trend lines through the data.
RESULTS: The displacement rate at which uniaxial tensile testing is performed has significant effects on the values of extension at peak load and initial stiffness, but not on the peak load.
CONCLUSIONS: When urogynecological prostheses are submitted to uniaxial tensile testing, studies at more than one displacement rate should be performed. More importantly, these displacement rates should be within the range of applicability.