Graft materials have been employed in repairing defects or hernias throughout the body. The purpose of grafts is to either completely replace “weak” tissue by spanning across that tissue or to provide a scaffold for fibroblast infiltration. The patient’s own connective tissue may grow into the graft, and, if the graft is degradable, replace the graft as a supportive structure. An ideal graft material should (i) be nonantigenic, (ii) exhibit a low infection rate, (iii) decrease or negate recurrence of anatomic defects, (iv) cause no harm with respect to bowel or renal function, and (v) be relatively inexpensive. Graft materials include autologous tissues, cadaveric allografts and fascia, dermis and other connective tissues, xenografts from animal sources, and various synthetic materials. Allografts and xenografts are treated with processes to remove living cells, thus negating their antigenic potential and allowing them to serve as a temporary connective tissue scaffold. It is assumed that fresh, autologous grafts work similarly; however, there may be some fibroblast survival in fresh harvested tissue. Autologous grafts have limitations in size and shape compared with tissue taken from cadaveric or animal sources. Synthetic grafts are permanent and, as long as the tissues to which they are secured retain their position and strength, they should be durable. Autografts, allografts, and xenografts depend on adequate tissue growth from the subject and potentially may have higher failure rates than synthetic ones. Synthetic grafts are more subject to erosion. Graft erosion may produce bothersome discharge, pain, and sexual dysfunction with vaginal scarring. This may be more likely to occur in women with attenuated, scarred, or less vascular tissue at the time of the repair. More loosely woven polypropylene meshes appear to exhibit fewer problems with erosion and infection than the synthetic graft material that was previously used (109–113).
Midurethral sling procedures that use such mesh have reported erosion rates of 1% or less as compared with rates as high as 6% with more tightly woven polypropylene and polyethylene grafts (109–113). A greater incidence of graft infection has been reported when other synthetic grafts are used. One would expect higher rates of erosion and infection when large pieces of graft material are used adjunctively to the vaginal wall; however, there have been favorable reports in which loosely woven polypropylene mesh was used in this manner. Small areas of eroded polypropylene graft may be removed with the surrounding tissue to the point where there is good tissue growth into the graft, and the defect can then be closed. Graft erosion into the bladder, urethra, or rectum is less common than into the vagina. When erosion occurs, however, management is more difficult and long-term adverse effects more common. Numerous surgeons have been reticent to use synthetic graft materials to augment paravaginal musculoconnective tissue support because of complications from erosion. There remains a need for long-term follow-up on patients who have repairs with graft material, not only to assess anatomical results and complications, but also to assess subsequent sexual function, presence and absence of pain, and patient satisfaction.