Definition & Overview
Urinary sphincter replacement is a surgical procedure that replaces the non-functioning biological urinary sphincter with an artificial one. The new artificial urinary sphincter (AUS) installed functions just like the natural sphincter to allow normal urination.
The urinary sphincter is a circular muscle structure responsible for controlling the flow of urine. A normal functioning sphincter can prevent urine from leaking and control the flow until the brain signals it for voluntary voiding. As the bladder is filled with urine, nerve signals instruct the sphincter to stay contracted while the bladder is relaxed. When the bladder is full, nerve signals then instruct the muscles in the bladder walls to squeeze, allowing urine out of the bladder towards the urethra. However, there are cases when the sphincter fails to function, leading to urinary incontinence (UI), a condition characterised by uncontrolled leakage of urine.
Urinary incontinence due to sphincter malfunction is a distressing condition that may be classified into:
Stress incontinence - This is linked to prostate gland removal or radical prostatectomy surgery (such as in the treatment of Prostate cancer). The surgery can damage the sphincter or nearby nerves that can lead to the weakening of sphincter. Any added pressure such as coughing, sneezing or straining may lead to leakage of urine.
Total incontinence - A condition when the urinary sphincter muscle no longer works causing the urine to leak from the bladder all the time.
Who Should Undergo and Expected Results
The most important body part in urinary continence is the urinary sphincter. When it is damaged as a result of treatment or due to age, ongoing incontinence will happen.
The main treatment available for this condition is sphincter replacement. AUS is recommended for patients whose urinary incontinence can no longer be managed with non-surgical means including conveens or sheaths and incontinence pads.
It is a relatively quick procedure with high success rates. However, before the procedure is recommended, doctors have to evaluate whether incontinence is indeed linked to sphincter problems.
How is the Procedure Performed?
An artificial sphincter used for this procedure is a balloon-like device made of silicone rubber. It consists of three parts: a balloon reservoir, a cuff, and a pump. Once turned on, the fluid inside the balloon flows out into the cuff. Once filled, it exerts pressure on the urethra to prevent urine from leaking out. Once ready to urinate, the pump is pressed to relax the cuff and allow urine to fall out.
Before surgery, prior preparations are usually done which include the administration of antibiotics and advising the patient to avoid fluid intake hours before the procedure. A general or spinal anaesthesia is then administered.
Once the anaesthesia is in full effect, an incision will be made to access the urethra. For men, the incision is made in the perineum (the area between the anus and penis) or the scrotum. For women, it is either in the vaginal area or abdomen. The surgeon will then make necessary measurements to determine the correct the cuff size of the AUS before placing it around the urethra. The balloon reservoir may be placed inside the lower abdomen through a small incision. The pump is positioned afterwards. For men, it will be placed in the scrotum, while for women, in the labia through a small cut. Once in place, the tubing from the cuff and balloon reservoir will be joined together with the pump. The surgeon will test to determine whether the pump works properly before the stitches are sutured and covered with a bandage.
The procedure takes about an hour to complete. After surgery, a Foley catheter will be temporarily placed to drain urine until the AUS can be used. Pain medications and antibiotics are also administered to help prevent infection. The AUS will not be used until about 6 to 8 weeks after surgery, when the area has completely healed.
Possible Risks and Complications
Urinary sphincter replacement is a safe procedure with high success and satisfaction rates. However, in some cases, complications do occur. These include:
- Failure of artificial sphincter to work as expected
- Difficulty urinating after surgery
- Damage to the urethra, bladder, or nearby tissues
- Bruising or swelling of the treatment area
- The possibility of another surgery to fix or replace AUS
Magera JS Jr, Inman BA, Elliott DS. Does preoperative topical antimicrobial scrub reduce positive surgical site culture rates in men undergoing artificial urinary sphincter placement?. J Urol. 2007 Oct. 178(4 Pt 1):1328-32; discussion 1332.
Henry GD, Graham SM, Cleves MA, Simmons CJ, Flynn B. Perineal approach for artificial urinary sphincter implantation appears to control male stress incontinence better than the transscrotal approach. J Urol. 2008 Apr. 179(4):1475-9; discussion 1479.