Feasibility of using a computer modeling approach to study SUI Induced by landing a jump.

Stress urinary incontinence (SUI) occurs due to anatomic and/or neurologic factors involving connective tissues, muscles and nerves. Although SUI is more common in post-menopausal and multiparous women, studies have also shown a high prevalence of SUI in young, physically fit female athletes. With a goal toward dynamic subject-specific mechanical characterization of the interaction between anatomical structures during physical activities that elicit SUI in females during physical or daily activities, a computer aided design (CAD)-based computer model of the female pelvis has been developed to test the feasibility of the computer modeling approach in understanding the measurable differences between stress-continent and stress-incontinent women. In the present study, a fluid-structure interaction analysis was conducted by using the finite element (FE) analysis technique based on the CAD-based computer model of the female pelvis to investigate the urine leakage in females during jumping. To the best of our knowledge, this is the first application of a fluid-structure interaction FE analysis approach in understanding the mechanisms of SUI in females. Through a series of computer simulations, the effects of varying impact forces determined by jumping height and bladder volume were investigated. The dynamic computer simulation results revealed that jumping heights have a significant influence on the volume of urine leakage caused by the landing impact of jumping. Bladder volume did not have a significant influence on leakage when the jumping heights were smaller than 1 ft, which indicates that normal walking (corresponds to a jumping height smaller than 0.1 ft) is not the primary cause of urine leakage for healthy females. The computer simulation results also showed that the deformation difference between the anterior and posterior portion of the female pelvis causes opening of the urethra and resultant urine leakage. The present study demonstrates the feasibility of using a computer modeling approach to study female SUI during physical and daily activities.