Highly purified collagen coating enhances tissue adherence and integration properties of monofilament polypropylene meshes

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Complications related to tissue integration of polypropylene implants used in the treatment of pelvic organ prolapse are relatively prevalent. Collagen, a biocompatible, less immunogenic material with modulating properties on the inflammatory process, may improve polypropylene integration. The objective was to study biomechanical and histological effects of monofilament polypropylene mesh coated with purified collagen gel. Forty rats were implanted with two fragments of polypropylene mesh in their abdominal walls (one on each side of the linea alba). One of the fragments had a collagen gel coating (group I) while the other one did not (group II). The animals were euthanized at 7, 14, 90, and 180 days after implantation and their abdominal walls were excised for analysis. The biomechanical study showed that mesh adherence to neighboring tissue increased significantly in group II (p < 0.05). Acute (p < 0.001) and chronic (p = 0.004) inflammatory responses as well as granulation tissue formation (p = 0.001) were less intense in group II at 7 and 14 days. Granulomatous inflammation and foreign body reaction was less significant at 7 days in group II (p = 0.029 and p < 0.001). The birefringence analysis showed higher mean brightness density in the late phase of implantation in group II meshes (p = 0.000). Polypropylene mesh coated with purified collagen gel increases adherence to tissue, promotes a less intense and lasting inflammatory response and triggers a greater organization and packing arrangement of collagen fibers in the late phase of implantation.241017471754Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)FAPESP [2010-01757-0

Primary fixation of mini slings: a comparative biomechanical study in vivo

Introduction and Objectives: The mini sling concept for stress urinary incontinence is an anatomical approach that involves placing a midurethral low-tension tape anchored to the obturator internus muscles bilaterally. They overcome the blind passage of long needles and all the related complications. There are many different devices available and because these are outpatient procedures, primary fixation plays an important role in the outcome. The objective is to evaluate the primary fixation of the various devices of attachment of the commercially available mini-slings through biomechanical tests. Materials and Methods: A total of 45 Wistar rats were divided in 3 groups of 15 rats each. They underwent 5 subcutaneous implantation of different mini slings and one polipropilene mesh (control), as follows: TVT-Secur (R) (Gynecare, USA), Type 1 polypropylene mesh (control); Ophira Mini Sling System (R) (Promedon, Argentina), Tissue Fixation System (R) (TFS PTY, Australia), Zipper Sling (R) and "T device" (Prosurg, USA). The abdominal wall was removed on bloc at different times after implant for biomechanical evaluation, which consisted in application of unidirectional force to the extremity of the fixation system or mesh, until it was completely removed from the tissue using a tension meter (Nexygen 3.0 Universal Testing Machine - LLOYD Instruments). The force was measured in Newtons (N). Results: There was signifi cant difference in the resistance to extraction among the different fixation systems. At 7 days the Ophira Mini Sling System (R) presented the best fixation and "T dispositive" the worst. Conclusion: Ophira mini sling System (R) presented the best primary fixation at 7 degrees, 14 degrees and 30 degrees days. The impact of this feature in the clinical setting needs to be verified.38225826