Graft‐related complications and biaxial tensiometry following experimental vaginal implantation of flat mesh of variable dimensions

Abstract

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.

Morphological and Functional Changes in the Vagina following Critical Lifespan Events in the Ewe

“…Sheep have been frequently used in vaginal surgery training that is, vaginal hysterectomy or transvaginal meshes insertion [56,57]. The second approach was used also in reproductive medicine research to test novel implant materials that is, collagen coated or electrospun meshes [13,15,58,59]. Other methodologic strengths are that we used ball-burst testing which more closely represents the in vivo-biomechanical situation as compared to uniaxial testing, often used in the literature.…”

“…Sheep may be alternatives as their pelvic floor anatomy and dimensions as well as the microscopic architecture have many similarities to that of humans [11,12]. We and others have recently become interested in sheep for pelvic floor research and experimental surgery [13][14][15]. For that purpose, we previously compared the pelvic floor anatomy and tissue composition of reproductive, pregnant, and postpartum ewes to that of women [11,12,[16][17][18].…”

Stem cell augmented mesh materials: an in vitro and in vivo study

“…In fact, in a rabbit model, histological and biomechanical differences between abdominal and vaginal implantations were noted [31]. On the other hand, no biomechanical differences were noted when a synthetic material was implanted on the abdomen and in the vagina of a sheep model [32]. However, this is uncertain in the rat owing to the limitation of the vaginal route in this model.…”

Synthetic Materials Used in the Surgical Treatment of Pelvic Organ Prolapse: Problems of Currently Used Material and Designing the Ideal Material

“…Recent animal studies in sheep confirmed a site specific response to implanted PPL mesh, where a 5 × 5 cm piece of PPL mesh led to contraction and erosion in 3 out of 10 sheep in 12 months when implanted vaginally in contrast to no erosions in abdominal implantations [49]. The animal studies also showed that the host response to the PPL initiated by macrophages in the mesh-tissue interface was mainly an M1 (proinflammatory) response, instead of an M2 (remodeling) response, characterized by secretion of matrix metalloproteinases and pro-inflammatory cytokines leading to a vigorous foreign body reaction [50].…”