Reduction of urethral pressure in response to stress: relationship to urethral mobility

It has been postulated that one factor involved in the pathophysiology of stress urinary incontinence is the sustained decrease in urethral closure pressure in response to a sudden increase in intra-abdominal pressure. Twenty-one patients with stress-related pressure decrease (group 1) and seven patients with stable pressures (group 2) were studied. Although closure pressure in group 1 decreased approximately 27% in response to a single cough in a static setting, when studied dynamically with pressure profiles before and after coughing, there was no pressure decrease seen. The evidence presented suggests that the phenomenon of pressure decrease is in actuality an artifact of measurement and not a true physiologic event. The degree of urethral mobility is related to the perceived pressure decrease.