Treatment of stress urinary incontinence: recent developments in the role of urethral injection.

Stress urinary incontinence is prevalent in adult women and has a considerable impact on quality of life. However, it often remains undiagnosed and therefore untreated. Non-invasive treatment is likely to be offered in mild cases and may entail physiotherapy, minimally invasive devices or pharmacotherapy. Surgical intervention is widely considered as the only effective option for more severe cases. These strategies are not suitable for all patients, and urethral injection represents an alternative, minimally invasive procedure. The choice of the bulking agent is the key to the success of this treatment: the most extensively studied are silicone, polytetrafluoroethylene and bovine collagen. However, doubts regarding the safety and efficacy of these materials has led to the development of carbon-coated zirconium beads, calcium hydroxylapatite and dextranomer/hyaluronic acid (Dx/HA) copolymer. Of these, the most clinical experience has been gained with Dx/HA copolymer. Until 2 years ago, urethral injection could only be administered endoscopically. The recent development of devices for 'blind' injection has increased the speed and convenience of urethral injection, removing the need for surgical facilities. Although few data are yet available, it is conceivable that urethral injection administered 'blind' may in future be considered as an option for all patients failing non-invasive treatment.