Injectable agents in the treatment of stress urinary incontinence in women: where are we now?

Periurethral bulking agents have been used for decades. The only currently available agents (in the United States) include glutaraldehyde cross-linked collagen, autologous fat, and carbon bead technology. Initial subjective cure rates with collagen are acceptable, but with the majority of women requiring reinjection. The risk of allergic phenomena complicates collagen use. Autologous fat injection is initially effective in >50% of women, but resorption and fibrous replacement hamper the stability of the transplanted graft. Polytetrafluoroethylene and silicone are not currently approved by the US Food and Drug Administration because of particle migration. Materials in development include biologic agents such as allogeneic human collagen and autologous cartilage. Developmental synthetic agents include microballoon technology, hyaluronic acid with or without microsphere technology, hydroxylapatite, and a variety of polymeric technologies. Patient selection and material characteristics influence the optimal choice for injectable agent.