Properties Analysis of Biological Grafts Used in Pelvic Surgery

Abstract

Pelvic surgery addresses congenital malformations like Mullerian anomalies, pelvic organ prolapse or after radical intervention, while constructive surgery involves treatment of congenital/iatrogenic absence of organs: uterus or vagina. Intuitively, inert and nondegradable biomaterials appear ideal for this purpose, but surgical reality is that the persistence of a permanent foreign body in the wound has a lot of clinical postoperative disadvantages. This paper aims to discuss the properties of the biologic grafts, detailing the structure of biologic extracellular matrix, the biomechanical properties of biological grafts and the use of extracellular matrix in reconstructive pelvic surgery. A biologic graft used in pelvic surgery is a tridimensional extracellular matrix, acellular and of animal origin. It has as a low risk of transmission of viral and prionic infections and determines reduced inflammatory reaction and a low risk of rejection. The absence of crosslinking facilitates the colonization of the mesh by the host´s cells, thus avoids the foreign body reaction represented by the encapsulation of the mesh by the host. Our experience with clinical use of biological acellular grafts in reconstructive pelvic surgery includes oncoplastic surgery like in cases of vulvar cancer or neovagina reconstruction for Rokintansky syndrome, complications after prolapse surgery treated with polypropylene meshes or relapsing recto-vaginal fistulas. The biomechanical properties evaluated by tensile stress and elastic modulus revealed that biologic grafts with moderate collagen infiltration are the strongest. The degree of cross-linkage influences the rate of degradation and the degree of the inflammatory response triggered by the host organ. Cross-linked collagenous matrices induce little cell infiltration hence there is limited collagen remodeling and graft degradation. On the other hand, in non-cross- linked xenografts cell infiltration is greater with faster degradation rate and collagen production. The decrease in the mechanical strength of the graft materials is related to the lack of collagen infiltration into the material. In conclusion, taking into account the biomechanical properties of biologic grafts, these may be used in reconstructive pelvic surgery and oncoplastic surgery with little complications and good clinical results. They can be attached to large mucosal defects and on potentially septic tissue, they are mechanically resistant and they can be sutured on surrounding healthy tissue.