Urethral bulking agents are injected underneath the lining of the urethra (water pipe) to add extra bulk to the sphincter and aid closure of the bladder outlet. The procedure is performed under a short general or spinal anaesthetic. Between 2 and 5 millilitres of bulking agents are injected into the side of the urethra, just under the bladder using a special tube called a cystoscope. The procedure will take approximately 30 minutes. In the majority of cases, you will be able to go home on the same day as your procedure.