A urinary diversion is an operation performed to divert urine away from the bladder. Urine is made by the kidneys and drains down the ureters and is stored in the bladder until it is convenient for the person to empty it.

There are several reasons why a urinary diversion may be needed, these include:

• If a person develops cancer of the bladder or uncontrolled bleeding from the bladder after radiotherapy or some drugs, sometimes the only way to stop the bleeding or effectively rid the body of cancer is to operate and remove the bladder. This operation is called either a Radical Cystectomy in females or a Radical Cystoprostatectomy in males. Radical means complete, cyst means bladder, prostat refers to the prostate in males, and ectomy means removal of. If the operation is done for bladder cancer in females the uterus, ovaries, uterine tubes and the front wall of the vagina are also removed. For males, the prostate is removed. This is done because the bladder is situated next to all of these structures and in an attempt to fully rid the body of cancer the entire area needs to be cleared during surgery.
   
• In some conditions the bladder can only store urine in very small amounts. It may be unable to store urine at all so the urine runs away continuously, or it may not empty itself completely. Sometimes it is not possible to overcome these problems with drugs so surgery may be needed to keep the person dry by diverting the urine away from the bladder. Usually in this situation the bladder does not need to be removed.
   
• There may be damage to the nerve supply to and from the bladder to the brain. If the nerves that send messages between the bladder and brain do not function correctly, a number of problems can occur. There may be leakage of urine, or incomplete bladder emptying which can lead to loss of kidney function so bypassing the bladder resolves these problems.