Structural position of the posterior vagina and pelvic floor in women with and without posterior vaginal prolapse

Objective: The objective of the study was to compare pelvic structure location on magnetic resonance imaging (MRI) during maximal Valsalva among women with posterior prolapse and those with normal support. Study Design: Subjects (n = 37) had posterior vaginal wall (PVW) prolapse of +1 cm or greater. All underwent midsagittal, dynamic MRI. Structure locations (distal vagina, apex, perineal body, external anal sphincter) were determined. PVW length, levator and urogenital hiatus diameters, and prolapse diameter were measured. Results: Subjects had more caudal structures (P < .001) and larger hiatus diameters (P < .005); the posterior wall was longer, whereas the straight-line distance between the apex and distal vagina was shorter. In enteroceles, the apex was more ventrally displaced compared with rectoceles (P = .003). Unlike apical descent (r = -0.3; P = .1), PVW length and point Bp were correlated with MRI prolapse size (r = 0.5; P = .002; r = 0.7; P < .001, respectively). Conclusion: At maximal Valsalva on MRI, structures are more caudal in women with posterior prolapse. The posterior vaginal wall is longer; this length strongly correlates with prolapse size.