Magnetic resonance imaging-based three-dimensional model of anterior vaginal wall position at rest and maximal strain in women with and without prolapse.

INTRODUCTION AND HYPOTHESIS: Two-dimensional magnetic resonance imaging (MRI) demonstrates apical support and vaginal length contribute to anterior wall prolapse (AWP). This paper describes a novel three-dimensional technique to examine the vagina and its relationship to pelvic sidewalls at rest and Valsalva. METHODS: Twenty women (10 with AWP and 10 with normal support) underwent pelvic magnetic resonance imaging at rest and Valsalva. Three-dimensional reconstructions of the pelvic bones and anterior vaginal wall were created to assess morphologic changes occurring in prolapse. RESULTS: In women with AWP, Valsalva caused downward translation of the vagina along its length. A transition point separated a proximal region supported by levator muscles and a distal, unsupported region no longer in contact with the perineal body. In this latter region, sagittal and frontal plane "cupping" occurs. The distal vagina rotated inferiorly along an arc centered on the inferior pubis. CONCLUSION: Downward translation, cupping, and distal rotation are three novel characteristics of AWP demonstrated by this three-dimensional technique.