Biomechanical properties of synthetic and biologic graft materials following long-term implantation in the rabbit abdomen and vagina

Objective: We sought to evaluate the effects of anatomic location and ovariectomy on biomechanical properties of synthetic and biologic graft materials after long-term implantation. Study Design: A total of 35 rabbits underwent ovariectomy or sham laparotomy and were implanted with polypropylene (PP) mesh (n = 17) or cross-linked porcine dermis (PS) (n = 18) in the vagina and abdomen. Grafts were harvested 9 months later and underwent mechanical properties testing. Results: After implantation, PS was similar in strength (P = .52) but was twice as stiff as PP (P = .04) and had a maximal elongation only half that of PP (P < .001). Degradation of PS was associated with decreased ultimate tensile strength (P = .03) and elastic modulus (P = .046). Vaginal PP grafts shrunk more (P < .001) and were less stiff than abdominal PP grafts (P = .049) but were not different in strength (P = .19). Ovariectomy had no effect (P > .05). Conclusion: Cross-linked PS undergoes long-term degradation resulting in compromised biomechanical properties and thus is likely inferior to lightweight PP meshes for pelvic organ prolapse and incontinence procedures.