Comparison of biomechanical properties of polypropylene monofilament meshes of different weights implanted in the abdominal wall of female adult rats

Abstract

Advances in biomaterials allowed the use of meshes as prostheses for the treatment of vaginal prolapse. The conventional techniques based on the repair by sutures (site-specific corrections) have a high recurrence rate, therefore, the mesh becomes a potential option, especially for severe prolapses. It is known that the success of the procedure depends on good tissue integration of the mesh given by the biomechanical properties of the material and by the tissue trophic conditions. Objective: To compare the biomechanical properties of monofilament polypropylene meshes of different weights implanted in the abdominal wall of adult rats. Methods: will be used 36 Large Wistar rats, white, weighing between 200 and 250 grams, adult, in which will be implanted monofilament polypropylene mesh at the interface between the hypodermis and the anterior fascia of the abdominal muscles. Tests will be conducted in three experimental models: PLP-14g/m2 ("longitudinal'' analysis); PLP-14g/m2 ("transversal" analysis), and PLP-62g/m2. Biomechanical properties of lightweight fabrics will be analyzed in orthogonal directions, because they have different biomechanical properties in their direction, resulting from twisting of filaments PLP. The 36 rats will be divided into three groups of 12 rats (group 1, group 2, group 3). In each group, there will be 4 rats for each experimental model. In group 1, the rats will be euthanized after 7 days, in group 2 after 30 days, and in group 3 and 60 days after the procedure. The biomechanical study will be carried out with a precision tensiometer soon after the euthanasia, without processing the material. The sample will be pulled in a uniaxial direction until it becomes detached from the tissue interface. The variables will be maximum load; deflection to maximum load, work to maximum load; consistency of the material, in addition to the values of load, deflection, and work performed at the time of detachment of the screen. Data will be stored and analyzed statistically. (AU)