Beyond collagen: injectable therapies for the treatment of female stress urinary incontinence in the new millennium

Shortcomings in regard to in vivo stability have hampered the ability of bovine glutaraldehyde cross-linked collagen to achieve long-term, durable success rates, fostering a continuing research effort in pursuit of the "ideal" injectable agent. The fields of biotechnology and materials science have enabled the development of newer agents, rapidly expanding the armamentarium of injectables available to the urologist. This article comprehensively reviews the tenets of injection therapy for the treatment of female stress urinary incontinence and currently available and investigational agents.