Related Experiment Video

Updated: May 4, 2026

Quantification of Levator Ani Hiatus Enlargement by Magnetic Resonance Imaging in Males and Females with Pelvic Organ Prolapse
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Quantification of Levator Ani Hiatus Enlargement by Magnetic Resonance Imaging in Males and Females with Pelvic Organ Prolapse

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Perineal Membrane Structural Changes: An Unstudied Aspect of Prolapse

Fernanda Pipitone1,2, Carolyn W Swenson3, John O L DeLancey4,5

  • 1Disciplina de Ginecologia, Departamento de Obstetricia e Ginecologia, Faculdade de Medicina, Universidade de Sao Paulo, Av Dr Eneas de Carvalho Aguiar, 255, Sao Paulo, 05403-000, Brazil. fernanda.pipitone@gmail.com.

International Urogynecology Journal
|May 2, 2026
PubMed
Abstract

Insights

Pelvic organ prolapse is linked to abnormalities in the perineal membrane (PM), including increased separation and widening. These PM changes may contribute to prolapse development and progression.

Area of Science:

  • Anatomical imaging and biomechanics
  • Pelvic floor disorders
  • Connective tissue abnormalities

Background:

  • The perineal complex, comprising the perineal membrane (PM), perineal body, and levator ani muscles, is crucial for pelvic hiatal closure.
  • Impairments in the connective tissues of the perineal complex can lead to hiatal closure dysfunction.
  • The specific role of the perineal membrane in pelvic organ prolapse (POP) remains poorly understood.

Purpose of the Study:

  • To test the hypothesis that pelvic organ prolapse involves abnormalities of the perineal membrane.
  • To compare the morphology of the perineal membrane between young women with prolapse and parous controls.
  • To utilize a validated MRI-based reconstruction and analysis technique for PM assessment.

Main Methods:

  • Secondary analysis of MRI data from two prior studies.
  • 3D reconstruction and surface modeling of the perineal membrane using specialized software (3D Slicer®, Rhino®).
  • Measurement of six key PM parameters: swinging door angle, visible bony origin length, hiatal dimensions (anteroposterior diameter and area), PM surface area, and midline separation. Statistical comparisons included t tests, Cohen's d, correlations, and stepwise regression.

Main Results:

  • Women with prolapse exhibited significantly altered PM morphology compared to controls.
  • Key differences included a 23% greater midline separation, 30% larger hiatal area, 26% larger hiatal anteroposterior diameter, 17% longer bony origin, and 26% larger PM surface area.
  • Levator ani status, midline separation, and PM surface area were independent predictors of prolapse, accounting for 76% of the variance.

Conclusions:

  • Pelvic organ prolapse is associated with significant alterations in perineal membrane structure, characterized by loss of central connection, hiatal elongation, and widening.
  • These findings suggest that PM abnormalities play a role in the pathophysiology of pelvic organ prolapse.
  • Further research with larger cohorts is warranted to confirm these findings and inform the development of targeted surgical repair techniques for prolapse.
Keywords:
Magnetic resonance imagingPelvic organ prolapsePerineal membraneUrogenital diaphragmUrogenital hiatus

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