Warping of the levator hiatus: how significant is it?
Date
2016
Type:
Artículo
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4
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Publisher
John Wiley & Sons
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Abstract
OBJECTIVES: The levator hiatus is the largest potential hernial portal in the human body. Excessive
distensibility is associated with female pelvic organ prolapse (POP). Distension occurs not just
laterally but also caudally, resulting in perineal descent and hiatal deformation or 'warping'. The aim
of this study was to quantify the warping effect in symptomatic women, to validate the depth of the
rendered volume used for the 'simplified method' of measuring hiatal dimensions and to determine
predictors for the degree of warping.
METHODS: This was a retrospective study utilizing records of patients referred to a tertiary
urogynecological service between November 2012 and March 2013. Patients underwent a
standardized interview, clinical assessment using the POP quantification system of the International
Continence Society and four-dimensional translabial ultrasound. The craniocaudal difference in the
location of minimal distances in mid-sagittal and coronal planes was determined by offline analysis
of ultrasound volumes, and provided a numerical measure of warping. We tested potential
predictors, such as demographic factors, signs and symptoms of prolapse, levator avulsion and
levator distensibility, for an association with warping.
RESULTS: Full datasets were available for 190 women. The mean craniocaudal difference in location
of minimal distances in mid-sagittal and coronal planes was -1.26 mm (range, -6.7 to 4.6 mm;
P < 0.001). This measure of warping was associated with hiatal area on Valsalva maneuver (r = -
0.284; P < 0.0001) and signs of significant prolapse on clinical and ultrasound examination (both
P < 0.0001).
CONCLUSIONS: The plane of minimal dimensions of the levator ani hiatus is non-Euclidean, i.e.
warped, and the degree of warping is associated with hiatal distension, or 'ballooning', and with
POP. However, the degree of warping is minor, the largest difference we found in the location of
the plane of minimal dimensions being 6.7 mm. Hence, our results support the determination of
hiatal area in a rendered volume of 1-2 cm in depth.
Description
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Citation
Dietz HP, Severino M, Kamisan Atan I, Shek KL, Guzman Rojas R. Warping of the levator hiatus: how significant is it? Ultrasound Obstet Gynecol. 2016 Aug;48(2):239-42.
Keywords
4D ultrasound, female pelvic organ prolapse, levator hiatus, measurement, translabial ultrasound