BERKELEY, CA (UroToday Inc.) - Any natural or synthetic substance that incorporates of integrates into a patient's tissues during treatment is defined as a biomaterial. The role of the biomaterial is to perform, supplement, or replace a natural function that is attenuated or lost. The ideal compound should be inert, sterile, noncarcinogenic, and mechanically durable, should cause no inflammatory or immune reaction, must withstand modification by body tissue, and should be inexpensive, convenient, and easy to use.

Pelvic organ prolapse with or without stress urinary incontinence (SUI) can be expected to affect 11% of all American women in a lifetime and is a major healthcare problem. Nearly 200,000 women undergo prolapse surgery in the U.S. every year. In a recent review, M. E. Karlovsky and colleagues from Long Island Jewish Medical Center examined the currently available biomaterials and make recommendations regarding their usage. The review is found in the September, 2005 issue of Urology.

The review starts with autologous fascia, which many consider the gold standard. Advantages for its usage included its ease of harvest, durability and the fact that it is native tissue. Disadvantages include the morbidity of the harvest, and the potential for loss of durability if placed in a host in which collagen breakdown might be a systemic illness rather than a local problem. Fascia lata has some of the same advantages and concerns.

Cadaveric allografts may decrease morbidity due to the absence of the need for a harvest procedure. Controversy exists as to whether the irradiation and freeze-drying, required to decellularize and sterilize the tissue, may lead to loss of durability and tensile strength. Allografts may also vary widely in tensile strength and collagen fiber orientation depending on site of harvest and even by maker and batch.

The recurrence rate of prolapse after traditional anterior vaginal repair is approximately 30% which led to the development of newer biomaterials. Xenografts such as processed porcine tissue, small intestine submucosa (SIS) and dermis, has gained popularity as a sling material for correcting SUI. SIS is comprised of only collagen once the cellular components are removed. Several growth factors are added to promote host cell infiltration usually within 90 to 120 days. Good early and medium-term results are available to support its use of pelvic floor reconstruction.

Mesh is available as absorbable synthetic mesh such as Vicryl (polyglactic acid) and Dexon (polyglycolic acid) and nonabsorbable mesh such as polypropylene, Dacron or Gore-Tex. The use of the absorbable mesh has been discouraged because of poor scar formation, poor tensile strength, and high recurrence rates. Polypropylene mesh is a monofilament mesh that is available in a variety of different pore sizes to maximize host tissue invasion or to provide the highest tensile strength. A common known porous polypropylene mesh is TVT used in mid-urethral slings. There continues to be common reports of erosion of synthetic slings, however, even leading a product named ProteGen, which was a woven polyester mesh, to be removed from the market.

The authors choose to use polypropylene slings secondary to the fact that it is readily available, of consistent quality, low cost, and disease free. In their series of 58 patients undergoing sling procedure, the 5 year cure rate was 81% with no erosions or infections. The have equally good results with a series of 29 patients who underwent sacrospinous fixation with a failure rate of 6.9% at 2 years and no erosions.

Urology. 2005 Sept; 66(3): 469-475