Long-term tensile properties of tension-free vaginal tape, suprapubic arc sling system and urethral sling in an in vivo rat model.

PURPOSE: Slings have gained widespread popularity for stress urinary incontinence. Commonly used sling materials include TVT, SPARC and Stratasis. To our knowledge no long-term comparative in vivo studies assessing the tensile strength of these materials have been reported. We examined tensile properties during a 1-year period after in vivo implantation in a rat model.
MATERIALS AND METHODS: A total of 30 Sprague-Dawley rats had 1 x 2 cm strips of TVT, SPARC and Stratasis implanted on the inner abdominal wall. The animals were grouped for sacrifice at 6 weeks, and 3, 6, 9 and 12 months, at which time the tape materials along with their associated fibrotic tissue were removed. Tensile properties were analyzed.
RESULTS: The initial control mean break load for TVT, SPARC and Statasis was 0.717, 0.453 and 0.298 kg, respectively (p=0.001). At 6 weeks, and 3, 6, 9 and 12 months TVT had a mean break load of 0.525, 0.678, 0.696, 0.568 and 0.522 kg, respectively. During the same intervals SPARC had a mean break load of 0.516, 0.596, 0.450, 0.514 and 0.496 kg, respectively. Stratasis had a mean break load of 0.147, 0.183, 0.132, 0.062 and 0.070 kg, respectively.
CONCLUSIONS: TVT has tensile properties comparable to those of SPARC and each is superior to Stratasis. These differences in tensile properties of the mesh material along with the fibrous reaction may have clinical implications in terms of the success of pubovaginal slings made with such materials.