There are three basic types of urinary incontinence: stress incontinence, an over-active bladder, and overflow incontinence. In stress incontinence, something that you do increases the pressure in your abdomen enough that it pushes urine past the urethra. This may occur during a cough, sneeze, lifting something heavy or landing hard after you have jumped. The basic idea is that some external force pushes on the bladder and forces a squirt of urine out.
Women with an over-active bladder are not able to wait until it is convenient to empty their bladder. They find that “when I have got to go, I have got to go”. This occurs because the normal ability to tell the bladder to wait until it is the right time is weakened. When need is felt to empty the bladder, telling the bladder to wait simply does not work any more.

The third type of incontinence some women experience is because of overflow incontinence or an inability to empty the bladder completely. This occurs in many older women when the bladder fails to completely empty all of the urine out and the bladder becomes progressively swollen. In this instance, the bladder cannot do its job properly and urine can leak out because of bladder overflow.

• Stress Urinary Incontinence
  In stress incontinence, the strength of the urethra and muscles of the pelvic floor to hold urine in during increases in abdominal pressure is weakened. The muscles of the urethra themselves are not strong enough to hold urine in the bladder during a strong cough. The muscles and ligaments of the pelvic floor must assist them. During a strong cough or sneeze, the downward force of abdominal pressure on the urethra squeezes it against a supporting layer to close it. This is similar to what would happen if the downward force of your body’s weight stepped on a garden hose and stopped the flow of water coming through it. As long as the supportive layer under the urethra is stiff, then this compression works. If that supporting layer becomes floppy, then the compression cannot work. If, you step on a garden hose, but the hose is on soft mud, then the flow of water cannot be stopped.
  
  In women who have stress incontinence, two things play a role in causing the incontinence. First, the layer that the urethra rests on is not as stiff as it should be. This can occur either because that layer has broken away from what normally holds it in place due to broken ligaments or because the muscles that normally contract to hold it in place are weak or damaged.
  
  Stress incontinence can also occur because the urethra is not weak and cannot help enough with the closing mechanism described above. If the urethral muscles are so damaged that they cannot squeeze tightly closed, then urine can come out of the urethra even though the layer it rests on is normal. This is called intrinsic sphincter deficiency because the sphincter muscles in the urethra are inadequate.
  
  Sling Procedure. The sling procedure, or suburethral sling procedure, refers to a particular kind of surgery using ancillary material to aid in closure of the urethral sphincter function of the bladder. It is performed as a treatment of severe urinary incontinence. The sling procedure, also known as the suburethral fascial sling or the pubovaginal sling, has many forms due to advances in the types of material used for the sling. Some popular types of sling material are Teflon (polytetrafluoroethylene), Gore-Tex®, and rectus fascia (fibrous tissue of the rectum). The surgery can be done through the vagina or the abdomen and some clinicians perform the procedure using a laparoscope—a small instrument that allows surgery through very small incisions in the belly button and above the pubic hairline.

  TVT - Tension Free Vaginal Tape. The tension-free vaginal tape (TVT) procedure refers to a type of sling operation used for treatment of stress urinary incontinence in women. The tape does not elevate the urethra, but provides a resistant platform under the mid-urethra to maintain continence against increases in intra-abdominal pressure. It is a minimally invasive and effective technique to resolve urinary stress incontinence.

• Over-Active Bladder
  Leakage occurs in women with an over-active bladder when they lose their ability to tell the bladder not to contract at inappropriate times. One example occurs when the nerves that go between the brain and the bladder are injured. In this instance, the bladder goes back to acting the way it did before toilet training and simply empties when it has reached a certain degree of filling. In this instance, you cannot tell it not to empty when it is not an appropriate time. This can occur in individuals with a spinal cord injury.
  
  Many women who have a normal spinal cord can still have an over-active bladder. Some damage to the nerves in the pelvis may have occurred making the bladder more difficult to control. There may not be a constant automatic emptying of the bladder but it may be more difficult for those women who keep from urinating when something happens that makes them feel like they need to urinate. This may be the sound of running water, stepping outside into the cold, seeing that a bathroom is near. In these instances, it is usually an appropriate time to empty the bladder but normal women can delay the urge to urinate for minutes until it is convenient. This kind of incontinence often occurs, for example, when someone has arrived home with a very full bladder and is getting into the house and heading towards the bathroom. Normally it is possible to delay urinating until you’re in the bathroom and seated on the toilet, but individuals with an over-active bladder may not be able to do this conveniently. Exactly why this occurs is not currently very well understood but it is probably a combination of nerve injury that makes it more difficult to tell the bladder not to contract, and weakness of the muscles that would normally hold on until a convenient time to empty the bladder.
   

• Overflow Incontinence
  In patients with overflow incontinence, the bladder becomes so swollen that the normal mechanisms of control cannot work. Many of these patients have the paradox of a bladder that will not empty itself properly when it is the right time to empty and yet will contract at other times.