Stress Urinary Incontinence (SUI)

Stress Urinary Incontinence (SUI)

Stress Urinary Incontinence (SUI)

Stress Urinary Incontinence (SUI) occurs not when you are stressed but when your bladder is placed under physical stress, usually due to pressure from the abdomenwhihc is called intra-abdominal pressure (IAP).
This happens for example when you sneeze, cough or jump. If your sphincters, pelvic floor muscles and supporting elastic tissues (fascia) can counteract this pressure by keeping the bladder neck up high and helping to close the urethra then you will stay dry. If they can’t, then you will leak urine in varying amounts – usually proportional to the amount of pressure. 

It is a fallacy that strong pelvic floor muscles are all you need to stay dry

Staying dry depends on your continence mechanism working, especially under pressure. The continence mechanism or stress continence control system consists of two parts:

The parts outside the urethra that support the bladder neck and urethra :                  

  • pelvic floor muscles 
  • elastic or fascial tissue (endopelvic fascia)

The parts inside the urethra that help keep it closed :   

  • urethral sphincter muscles – smooth and striated
  • vascular parts of the urethral walls which help them to stick together. Oestrogen plays a role here so as we lose oestrogen during menopause it is often harder to keep the urethra closed as tightly and women may leak more. This can be helped with topical oestrogen.

** The female urethra is 4 cm long compared to the male urethra at 20cm so men have more chance of keeping theirs closed which is one of the reasons men leak less than women unless they have had prostate surgery.
During a prostatetctomy, the prostate gland is removed and as the internal urethral sphincter sits within the part of the urethra that passes through the prostate this is also removed, leaving some men with less control and relying more on the other parts of the continence mechanism such as the pelvic floor muscles to stay dry.

  • All of these components have to work together to keep you dry especially when extra pressure is exerted downwards on the bladder from above – like a cough, sneeze, jump, lift etc.
  • If any part of the system is damaged, it can’t do its job, so you rely on the other components more. 
  • Pelvic floor muscle training is aimed at strengthening the pelvic floor muscles to help do their part, as well as ensuring they contract at the right time – just prior to the pressure of the cough or sneeze. Often this is enough to keep the urethra closed and one of the main reasons pelvic floor muscle training (PFMT) has been shown to be the best and first treatment that should be used for SUI.

For the pelvic floor to function at its best, it needs to work in sync with the diaphragm or breathing muscle. The diaphragm is a dome shaped muscle sitting below the lungs and above the abdominal contents (stomach, intestines etc)
As you breathe IN the diaphragm moves downwards, pushing down on the abdominal contents and pelvic organs and these in turn push down on the pelvic floor giving it a slight stretch.
As you breathe OUT the diaphragm comes up, reducing the pressure on the abdominal contents and pelvic organs and the pelvic floor rebounds slightly.

So, if you are having problems activating your pelvic floor try contracting on the out breath. 
Doing the same when under load eg lifting will help reduce the pressue downwards on the bladder and can in turn help reduce leaks.

A helpful mantra to remember is EXhale on EXertion


For the few that don’t respond to PFMT, it will usually be due to not enough support from the elastic tissues behind the urethra.
The pelvic floor muscles may be quite strong but if the elastic tissue has been stretched or torn then it can’t provide enough support to help close against the pressure of the cough or sneeze.
In these cases many women will be helped by using a urethral support like Contiform or with a continence pessary that can be sized and fitted by your gynaecologist or pelvic floor physio. If you also have a prolapse then a properly fitted pessary may solve both problems.


For a small percentage of women none of these options will work and surgery in the form of a mid-urethral sling or a bladder lifting procedure such as an anterior wall repair may be the answer.

For men, there is also a sling procedure that can be done.


How do I normally explain this to my patients?

To be less technical I like to use analogies to explain what is happening when you have stress incontinence.

My favourite, and the one that seems to resonate best with patients, is of the hose on the grass vs the hose on the driveway.

Imagine you have a hose lying on your driveway , attached to a sprinkler that is watering your garden.
A friend comes to visit and parks their car on the hose. The car's tyre will compress your hose and stop the flow of water to the sprinkler.

If, however, your hose is on the grass, attached to the sprinkler, and your friend parks their car on it then the car tyre won't compress it as much. It will slow the flow but not completely because the hose won't be completely squashed.

Think of the hose as your urethra.  If you can create a "driveway" as a firm backstop for your urethra by the pelvic floor muscles pulling firmly on the elastic, fascial tissue behind the urethra then the abdominal pressure is the tyre/car pushing down on it ( eg with a cough or a jump) the two pressures meet and compress the "hose" or urethra and no urine escapes.

If, however, you can only create a grassy backstop - if the muscles aren't strong enough, or they may be strong but the fascial, elastic tissue is a bit loose and can't be tensioned  (think of the comparison between elastic in a new pair of knickers compared to an old pair) you won't have a firm surface behind your "hose" which won't be fully compressed closed and some fluid will still come through - a little leak.

This is illustrated below using a foot stepping on the hose on concrete compared to grass. The car tyre seems to work better as an image for many people.

So you need strong muscles but you also need firm fascial tissue for those muscles to pull on.


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