Dynamic assessment of the vaginal high-pressure zone using high-definition manometery, 3-dimensional ultrasound, and magnetic resonance imaging of the pelvic floor muscles.

OBJECTIVE: We used a novel technique, high-definition manometry (HDM) that utilizes 256 tactile sensitive microtransducers to define the characteristics of vaginal high-pressure zone. STUDY DESIGN: Sixteen nullipara asymptomatic women were studied using HDM, transperineal 2-dimensional dynamic ultrasound and dynamic magnetic resonance (MR) imaging. RESULTS: Vaginal high-pressure zone revealed higher contact pressures in anterior and posterior directions compared with lateral directions, both at rest and squeeze. At rest, anterior pressure cluster is located 10 mm cephalad to posterior pressure cluster; with squeeze the latter moves in the cranial direction by 7 mm. Ultrasound and MR images revealed that the anorectal angle moves cephalad and ventrally during squeeze. Cephalad movement of posterior pressure cluster during squeeze is similar to the cranial movement of anorectal angle. CONCLUSION: We propose that the vaginal high-pressure zone represents the constrictor function and cranial movement of the posterior pressure cluster represents the elevator function of pelvic floor. HDM may be used to measure the constrictor and elevator functions of pelvic floor muscles.