Population Twenty adult parous Texel ewes.Methods Sheep were implanted with Gynemesh M, a 28-g/m² polypropylene mesh reinforced with polyglecaprone fibres, under general anaesthesia. Dissection into the rectovaginal septum was performed to accommodate a flat 50 9 50 mm (n = 10) or 35 9 35 mm (n = 10) mesh, which was sutured to the underlying tissues. A 50 9 50 mm mesh was laid over a primarily sutured, fullthickness, 40-mm longitudinal abdominal wall incision. Sacrifice was at 60 days (n = 10) or 90 days (n = 5).Main outcome measures The occurrence of exposure, the degree of contraction and examination of the biomechanical properties of explants with a minimum radius of 32 mm via biaxial tensiometry.Results Insertion of a 50 9 50 mm mesh led to exposures in 30% (3/10) of cases, and the average contraction rate was 52 ± 14%. In the 35 9 35 mm implants, there were no exposures, and the contraction rate was 25 ± 26.3%. Vaginal explants with no GRCs and of sufficient size had biomechanical properties that were comparable with those of abdominal explants. ConclusionVaginal mesh insertion is associated with GRCs, such as exposure and contraction. Although other factors probably play a role, this study illustrates that mesh size may also induce these complications. In a vaginal surgery model, clinically occurring GRCs can be reproduced. In addition, biomechanics of uncomplicated vaginal explants are comparable with those measured on abdominal explants.

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The properties of meshes used in reconstructive surgery affect the host response and biomechanical characteristics of the grafted tissue. Whereas durable synthetics induce a chronic inflammation, biological grafts are usually considered as more biocompatible. The location of implantation is another determinant of the host response: the vagina is a different environment with specific function and anatomy. Herein, we evaluated a cross-linked acellular collagen matrix (ACM), pretreated by the anti-calcification procedure ADAPT® in a sheep model for vaginal surgery. Ten sheep were implanted with a cross-linked ACM, and six controls were implanted with a polypropylene (PP; 56 g/m2) control. One implant was inserted in the lower rectovaginal septum, and one was used for abdominal wall defect reconstruction. Grafts were removed after 180 days; all graft-related complications were recorded, and explants underwent bi-axial tensiometry and contractility testing. Half of ACM-implanted animals had palpable induration in the vaginal implantation area, two of these also on the abdominal implant. One animal had a vaginal exposure. Vaginal ACMs were 63 % less stiff compared to abdominal ACM explants (p = 0.01) but comparable to vaginal PP explants. Seven anterior vaginal ACM explants showed areas of graft degradation on histology. There was no overall difference in vaginal contractility. Considering histologic degradation in the anterior vaginal implant as representative for the host, posterior ACM explants of animals with degradation had a 60 % reduced contractility as compared to PP (p = 0.048). Three abdominal implants showed histologic degradation; those were more compliant than non-degraded implants. Vaginal implantation with ACM was associated with graft-related complications (GRCs) and biomechanical properties comparable to PP. Partially degraded ACM had a decreased vaginal contractility.