STRESS URINARY INCONTINENCE

As described above, urethral support from the pelvic floor is essential for maintenance of continence during increases in intraabdominal pressure. In response to aging, multiple vaginal deliveries, chronic cough, or obesity, these supports may become damaged or weakened. As a result, the urethra becomes hypermobile and, during episodes of “stress” (i.e., coughing, straining), undergoes rotation and opening that permits leakage of urine. This phenomenon is known as stress urinary incontinence (SUI).

As described previously, the urethral sphincters also protect against incontinence in response to increased intravesical pressure via the guarding reflex. Although these sphincters were once thought to be normal in SUI, it is now known they may exhibit a variable degree of dysfunction that contributes to urine leakage. Significant dysfunction of the external urethral sphincter may reflect pudendal neuropathy, which can result from aging or prior pregnancy.