Introduction: Pelvic floor ultrasound plays a major role in urogynecologic diagnostics. Using 3D ultrasound we can identify integrity of levator ani and measure hiatal area in the axial plane. The main goal of our study was to measure hiatal area on Valsalva in a cohort of urogynecological patients. Furthermore, we aimed to correlate hiatal area with urogynecological symptoms, levator integrity and evaluate cut-off values for pelvic organ prolapse.
Materials and methods: In a retrospective analysis, we included 246 patients seen for urogynecological problems in our tertiary urogynecological unit. After a standardized interview and physical examination, a 3D pelvic floor ultrasound was performed. According to the cardinal urogynecological symptoms and signs, patients were categorized into three groups: pelvic organ prolapse, stress urinary incontinence and overactive bladder symptoms.
Results: Median age of our study population was 66 (range 29-94) years, median parity was 2.1 (range 0-9) with 17 (6.9 %) nulliparous women. Symptoms of overactive bladder in 71.1 % were most common, followed by 54.5 % symptoms of stress incontinence and 32.1 % symptoms of prolapse. On examination 49.2 % showed signs of prolapse. Levator avulsions on 3D ultrasound were detected in 20.7 %. Hiatal area was normally distributed with a median of 28.7 cm2 (range 10.4-50.0 cm2). Patients with levator avulsion had a significantly larger hiatal area (p < 0.001). Also patients with signs of prolapse had a significantly larger hiatal area (p < 0.001). There was no correlation between hiatal area and symptoms of overactive bladder (p = 0.374). Although not reaching statistical significance there was evidence of a smaller hiatal area for patients with stress incontinence (p = 0.016). In our cohort there were 33.7 % (83) women without ballooning, 27.2 % (67) showed mild, 18.3 % (45) moderate, 12.3 % (30) marked and 8.5 % (21) severe ballooning. The ROC curve analysis for hiatal area on patients with prolapse yielded an AUC of 0.755 [95 % CI (0.696-0.814)]. Using the Youden-Index we obtained 27.53 cm2 as a cut-off with a sensitivity of 0.70 and a specificity of 0.69.
Discussion: Hiatal area is a new repeatable diagnostic parameter. Its clinical application could improve our understanding of the pathophysiology of pelvic organ prolapse as a form of hiatal hernia.
Keywords: 3D ultrasound; Hiatal area; Lower urinary tract symptoms; Overactive bladder; Pelvic organ prolapse; Stress urinary incontinence; Urogynecology.