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A Hypothesis Generating the Mechanical Systems Underlying Posterior Vaginal Prolapse Based on Observed Displacements by Dynamic Magnetic Resonance Imaging

Qiu, Zhongyuan, MD; Song, Yanfeng, PhD

Female Pelvic Medicine & Reconstructive Surgery: September 20, 2018 - Volume Publish Ahead of Print - Issue - p
doi: 10.1097/SPV.0000000000000637
Original Article: PDF Only

Objective The aim of this study was to analyze quantified displacements of the posterior vaginal wall (PVW) on dynamic magnetic resonance imaging (MRI), which may generate hypotheses for the detailed mechanisms that underlie the development of posterior vaginal prolapse.

Methods Pelvic dynamic MRI scans were obtained for 12 women with normal vaginal structure (stage 0) and 62 women with 4 consecutive stages (1–4) of posterior vaginal prolapse. Structural locations (apex vagina, distal vagina, and mid–perineal body [PB]) and equidistant points along the PVW (points 4–6 were considered as midvagina) were identified, and PVW length, straight distance of PVW, levator ani parameters (levator hiatus length [LHL], levator hiatus width [LHW], levator plate angle, anorectal angle, and M line [ML]), urogenital hiatus, and prolapse diameter were measured at rest and maximal Valsalva, respectively. The displacement of these measurements was obtained.

Results From stage 0 to 2, the variables LHL, LHW, levator plate angle, anorectal angle, and ML increased gradually, but midvagina, distal vagina, and mid-PB were the opposite. From stage 2 to 3, apex vagina, midvagina, distal vaginal, mid-PB, LHL, LHW, and ML raised rapidly and peaked at stage 3, then declined at stage 4. In addition, the correlation coefficients between each measurement from stage 2 to 3 were statistically higher than those from stage 0 to 2.

Conclusions Quantified displacements of the PVW and its supporting structure were shown on dynamic MRI, and the mechanical mechanisms were hypothesized regarding the interaction between pressure and the support force contributing to the deformation of the PVW and the supporting structures.

This is an open-access article distributed under the terms of the Creative Commons Attribution-Non Commercial-No Derivatives License 4.0 (CCBY-NC-ND), where it is permissible to download and share the work provided it is properly cited. The work cannot be changed in any way or used commercially without permission from the journal.

From the Department of Obstetrics and Gynecology, Fuzong Clinical College of Fujian Medical University, Fuzhou, China.

Correspondence: Yanfeng Song, PhD, Department of Obstetrics and Gynecology, Fuzong Clinical College of Fujian Medical University, 156 West Second Ring North Road, Fuzhou, Fujian 350025, China. E-mail:

The authors have declared they have no conflicts of interest.

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