Interactions among pelvic organ protrusion, levator ani descent, and hiatal enlargement in women with and without prolapse

Abstract

Background Pelvic organ prolapse has two components; 1) protrusion of the pelvic organs beyond the hymen and 2) descent of the levator ani. The Pelvic Organ Prolapse Quantification system measures the first component, however, there remains no standard measurement protocol for the second mechanism. Objectives Test the hypotheses that 1) difference in the protrusion area is greater than the area created by levator descent in prolapse patients compared with controls and, 2) Prolapse is more strongly associated with levator hiatus compared to urogenital hiatus. Study Design Mid-sagittal MRI scans from 30 controls, 30 anterior predominant and 30 posterior predominant prolapse patients were assessed. Levator area was defined as the area above the levator ani and below the sacrococcygeal inferior pubic point line. Protrusion area was defined as the protruding vaginal walls below the levator area. The levator hiatus and urogenital hiatus were measured. Bivariate analysis and multiple comparisons were performed. Bivariate logistic regression was performed to assess prolapse as a function of levator hiatus, urogenital hiatus, levator area, and protrusion. Pearson correlation coefficients were calculated. Results The levator area for the anterior (34.0±6.5cm2) and posterior (35.7±8.0cm2) prolapse groups were larger during Valsalva compared to controls (20.9±7.8cm2, p<.0001 for both); similarly, protrusion areas for the anterior (14.3±6.2cm2) and posterior (14.4±5.7cm2) were both larger than controls (5.0±1.8cm2, p<.0001 for both). The levator hiatus length for the anterior (7.2±1cm) and posterior (6.9±1cm) were longer during Valsalva compared to controls (5.2±1.5cm, p<.0001 for both); similarly, urogenital hiatus lengths for the anterior (5.7±1cm) and posterior (6.3±1.1cm) were both longer than controls (3.8±0.8cm, p<.0001 for both). The difference in levator area in prolapse patients compared with controls was greater than the difference in protrusion area (14.0 ± 7.2cm2 v. 9.4 ± 5.9cm2, p<.0002). The urogenital was more strongly associated with prolapse than the levator hiatus (OR: 12.9, 95% CI: (4.1–39.2), OR: 4.3, 95% CI: (2.3–7.5)). Levator hiatus and urogenital hiatus are both correlated with levator and protrusion areas, and all were associated with maximum prolapse size (p≤0.001, for all comparisons). Conclusions In prolapse, the levator area increases more than the protrusion area and both the urogenital hiatus and levator hiatus are larger. The odds of prolapse for an increase in the urogenital hiatus are three times larger than for the levator hiatus, which leads us to reject both the original hypotheses.

The Combined Measurement of Pelvic Organ Mobility and Hiatus Area Improves the Sensitivity of Transperineal Ultrasound When Detecting Pelvic Organ Prolapse

“…Trauma to the puborectal muscle is associated with an enlarged levator hiatus (8,24,25). Therefore, we hypothesized that by combining pelvic organ mobility and hiatal area, we may be able to improve sensitivity.…”

“…However, the POP-Q system only provides information relating to the surface anatomy of the pelvic organs and does not consider underlying organs or functional anatomy ( 3 ). POP is characterized by ballooning of the levator hiatus and the protrusion of pelvic organs via a weakened pelvic floor ( 3 , 7 , 8 ). Transperineal ultrasound can detect both of these inner alterations and yields reproducible results ( 9 , 10 ).…”

“…Transperineal ultrasound can detect both of these inner alterations and yields reproducible results ( 9 , 10 ). Most previous studies that addressed the diagnosis of POP by transperineal ultrasound have measured only one parameter, either levator hiatus area or pelvic organ mobility ( 8 , 11 – 14 ). We hypothesized that the combined measurement of levator hiatus area and pelvic organ mobility may increase the sensitivity of transperineal ultrasound for the diagnosis of POP.…”

Malmström vacuum or Kielland forceps: which causes more damage to pelvic floor?

“…Instrumental delivery results in an increase in neonatal morbidity (subdural or cerebral hemorrhage, seizures and need for mechanical ventilation) and maternal morbidity (hemorrhage, perineal injuries). However, these are not the only injuries that occur during labor; there are other types of muscle trauma, such as levator ani muscle (LAM) avulsion, which can influence the future occurrence of pelvic floor dysfunction.…”

“…LAM injury caused during childbirth can lead to an increase in size of the levator hiatus and a decrease in muscle strength, contraction speed and resistance, and is associated with lower strain of the puborectalis muscle. In addition, LAM injury is associated with the development of pelvic organ prolapse, urinary incontinence and fecal incontinence during the postpartum period. LAM avulsion is defined as the disconnection of LAM muscle fibers from their insertion on the inferior pubic ramus and represents the primary hazard during vaginal delivery.…”