Delivery of injectable agents for treatment of stress urinary incontinence in women: evolving techniques.

PURPOSE: Periurethral bulking agents continue to be used as a minimally invasive alternative for management of stress urinary incontinence in men and women. Agents and delivery techniques will be evaluated and compared.

MATERIALS AND METHODS: The only agents currently approved by the United States Food and Drug Administration (FDA) include glutaraldehyde cross-linked collagen, autologous fat, and carbon bead/carrier gel technology. Several other agents are undergoing FDA trial evaluation. These agents differ in material characteristics (particle size, viscosity) that, in some cases, produce different immediate and delayed tissue responses or reactions.

RESULTS: Initial subjective cure rates with collagen are acceptable, but the majority of women require reinjection. The risk of allergic phenomena complicates collagen use. Carbon-based material appears to parallel collagen in durability, with the significant advantage of a nonimmunogenic response within host tissues. Autologous fat injection achieves early results similar to those with collagen, but is limited by resorption and fibrous replacement as well as local discomfort associated with harvesting procedures. Experience with newer agents is limited. Patient characteristics also influence response to injectable agents.

CONCLUSIONS: Injectable agent materials and delivery techniques continue to evolve. The optimal material is yet to be defined.