Research LetterLevator ani defect severity and its association with enlarged hiatus size, levator bowl depth, and prolapse size
Section snippets
Objective
There is a strong association between the development of pelvic organ prolapse and levator ani injury and urogenital hiatus (UGH) and levator hiatus (LH) enlargement.1 Because of the origin and insertion of levator ani, it is plausible that muscle injury affects hiatus size; however, the relationship between levator defect and hiatus size remains unclear. In a previous study,2 we found that UGH has a higher odds of predicting prolapse than LH and that the levator “bowl” deepens more than the
Study Design
Details of the design have been described previously.2 Using magnetic resonance images of supine women from 2 institutional review board–approved case-control studies on prolapse (University of Michigan IRBMED HUM00043445, approved 1/27/11 and HUM00031520, approved 6/28/09), we examined 30 patients with anterior prolapse, 30 patients with posterior prolapse, and 30 control subjects, who represented a range of pelvic support from normal to significant prolapse, both at rest and during Valsalva.
Results
For each levator defect score, mean measurements and ranges for UGH, LH, levator area, and protrusion area are presented in the Table. All Spearman rank coefficients indicate a significant, positive association with the measures, except for protrusion area during Valsalva. The R-squared values, which indicate the variation in each measure that can be explained by levator defect, ranged from 0.03 (protrusion area during Valsalva) to 0.12 (UGH at rest). The ranges of each measure varied widely
Conclusion
We reject our hypothesis that levator defect severity is the major determinant of hiatus size. Levator defect explains, at most, only 12% of the variation in LH or UGH size, levator area, and protrusion area. Although levator tear is related strongly to prolapse and defects are associated with increases in both hiatuses, only a small proportion of hiatus enlargement is attributable to levator defect. This suggests that other phenomena not currently measured in our common methods of quantifying
References (4)
- et al.
Interactions between pelvic organ protrusion, levator ani descent, and hiatal enlargement in women with and without prolapse
Am J Obstet Gynecol
(2017) - et al.
Size of the urogenital hiatus in the levator ani muscles in normal women and women with pelvic organ prolapse
Obstet Gynecol
(1998)
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2024, International Urogynecology JournalA comparison of MRI-based pelvic floor support measures between young and old women with prolapse
2023, International Urogynecology JournalComparison of the anterior pelvis and levator ani muscle on MRI in women with and without anterior pelvic organ prolapse
2023, International Urogynecology Journal
The authors report no conflict of interest.