The urinary bladder is a viscoelastic hollow organ, whose function consists in collecting and storing the produced amounts of urine to allow urinary voiding in bigger amounts and longer intervals. Bladder closure during the ordinary non-voiding condition is ensured via the tonus of the functional urethra. Four nerval control circuits (coming from the cortex, over the brain stem and the sacral micturition center, up to the urinary bladder), have been described by Bradley et al. (1976) which are responsible for the activation and coordination of the micturition reflex.
For urinary continence to be maintained, urethral pressure must be greater than bladder pressure at all times. The rise in urethral pressure before the increase in intra abdominal pressure (IAP) during a cough indicates that factors other than IAP are responsible for those increases. The pressure rise has been attributed to intra-urethral and periurethral structures (Sapsford 2001). With such a complex system, problems can arise in many ways, such as urinary incontinence (UI).
This is described as the involuntary leakage of urine that can result in a social or a hygienic problem (Sampselle 2000; NICE 2006). Three types of UI exist; Stress incontinence (SI) is characterized by involuntary loss of urine when IAP increased for example during coughing, sneezing, laughing or physical exertion. Urge incontinence is manifested by a strong desire to void that is occasionally associated with involuntary detrusor contraction and mixed continence is the combination of urge and SI (Sampselle 2000; NICE 2006). UI is a common problem amongst men and women (ref) occurring mostly in women.
The Department of Health (DOH) guidelines on incontinence (2000) suggests that the prevalence of incontinence in the United Kingdom (UK) is an average of 1 in 14 women aged between 15-44 and 1 in 7 women aged between 45-64. These numbers were taken from many studies with various methodologies (Button et al. 1998). There is limited information on the cost of managing UI in the UK although the estimated total cost in the United States of America (USA) in 1995 was $12. 4bn (i?? 7bn). Data from the Leicestershire MRC Incontinence Study estimates the annual cost to the National Health Service (NHS) of treating clinically significant UI at i??
536m (i?? 233m for women). The main cause of stress incontinence in women includes vaginal birth (Sampselle 2000) and it has found to be associated with nerve damage (Chiarelli, Murphy and Cockburn 2003). Women who have had at least one vaginal birth are more than 2. 5 times likely to report symptoms of incontinence than women who have never given birth (Sampselle 2000). It is now well established that childbirth can also reduce pelvic floor function, pelvic floor and urethral muscle damage (Chiarelli et al. 2003). The pelvic floor has three functions: Supportive, sphincteric, and sexual.
It provides support to the pelvic organs. At rest the pelvic floor muscle (PFM) maintains a minimal resting tone. With increased IAP the muscle activity increases (Hall and Brody 2005). The increase in pressure (e. g. laughing, coughing) and the forces of gravity encourages protrusion of the pelvic organs. Strong PFMs help to support the organs against increased IAP and enhance normal functioning. The PFM’s also provide a closure of the urethra and rectum for continence. Continence is preserved when the pressure in the urethra is higher than the pressure in the bladder (Hall et al. 2005).