Evaluation of the dynamic responses of female pelvic floor using a novel vaginal probe.

The female pelvic floor (PF) provides anatomical support to many visceral organs, such as uterus, bladder, urethra, vagina, and rectum. Physiologically, the PF is made up of a number of highly coordinated muscle groups organized to respond to postural and abdominal stresses to maintain continence. In this article, we describe a new methodology for the evaluation of PF strength using a novel vaginal probe design, having force and displacement sensors. This design was derived on the basis of imaging data showing that force/displacement characteristics are important determinants of the integrity of the PF function. The prototype probe used was constructed to evaluate the dynamic responses to slow voluntary contractions as well as reflex stress contractions. Initial clinical experiments were performed on nine healthy female subjects. The probe recorded the force and displacement signals on the anterior and posterior sides of the subjects' middle vaginal wall in voluntary PF muscle contraction and cough. The time domain and frequency domain characteristics of the dynamic responses, including the force and displacement responses, of the vaginal wall were measured and the power and energy associated with the dynamic responses of the PF were analyzed showing the differences between the dynamic characteristics of the voluntary PF muscle contraction and cough. Results show that voluntary PF muscle contractions have higher amplitudes, longer duration, and higher power than reflex contractions. The design of this probe enables the measurement of force and displacement during rapidly occurring events.