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Updated: Jan 2, 2026

Quantification of Levator Ani Hiatus Enlargement by Magnetic Resonance Imaging in Males and Females with Pelvic Organ Prolapse
Published on: April 17, 2019
Levator ani muscle (LAM) anatomical volume compared to age and body mass index (BMI) of patients
Allison Marie Wyman1, J P Tanner2, Renee Bassaly3
1Division of Female Pelvic Medicine and Reconstructive Surgery, Department of Obstetrics and Gynecology, Morsani College of Medicine, University of South Florida, STC Building, 6th Floor, 2 Tampa General Circle, Tampa, FL, 33606, USA. awyman@health.usf.edu.
Introduction And Hypothesis:
The levator ani muscle (LAM) plays an important role in pelvic support. Estimated levator ani subtended volume (eLASV) is an objective measurement of the anatomical volume of the LAM obtained from pelvic MRIs. The aim of this study was to assess the relationship between the anatomical volume of LAM to the age and body mass index (BMI) of a surgical patient based on our previous published cutoff value of increased LAM volume as measured by pelvic MRIs (eLASV > 38.5). We hypothesize that increasing age and BMI will both be correlated with the increasing volumes of LAM.
Methods:
We conducted a secondary analysis of an Institutional Review Board-approved retrospective cohort study. Standard protocol pelvic MRI measurements, including the pubococcygeal line, H-line, and M-line, were collected along with the calculated width of the levator ani hiatus (eLASV = - 72.838 + 0.598H-line + 1.217 M-line + 1.136WLH). Comparison to patients' age and BMI was assessed using the Wilcoxon-Mann-Whitney (continuous) and chi-square test (group). Spearman's correlation analysis was used to explore the relationship between age and BMI to eLASV.
Results:
Patients with elevated LAM volumes of eLASV were more likely to be older than patients with low volume of LAM, with median age 65 (37, 83) vs. 49.5 (28, 72), respectively (p < 0.001). We observed no difference in median BMI between patients with elevated volumes of eLASV compared with patients with low volumes of eLASV.
Conclusions:
Increasing age of women appears to be directly related to elevated volumes for levator ani muscle morphology when measured with eLASV.
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