Objective: The levator hiatus defines the 'hernial portal' through which female pelvic organ prolapse develops. Hiatal area may therefore be an independent etiological factor for this condition. In this retrospective study we defined 'normality' for hiatal area by assessing its relationship with symptoms and clinical signs of prolapse.
Methods: Datasets of 544 women seen in a tertiary urogynecological unit were assessed. Patients had undergone an interview, clinical examination and three-/four-dimensional (3D/4D) pelvic floor ultrasound imaging. All analysis was performed off-line, blinded against clinical data.
Results: Information on prolapse symptoms was available for 538 women and 171 (32%) of these complained of such symptoms. There was a strong statistical relationship between hiatal dimensions, both at rest and on Valsalva maneuver, and prolapse symptoms (all P < 0.001). Receiver-operating characteristics (ROC) curve analysis yielded an area under the curve of 0.65 (95% CI, 0.60-0.70) for hiatal area at rest and 0.71 (95% CI, 0.66-0.76) for hiatal area on Valsalva. Cut-offs of 25 and 30 cm(2) on Valsalva gave sensitivities of 0.55 and 0.34 and specificities of 0.77 and 0.86, respectively, for detecting symptomatic prolapse. Similar values were obtained when significant prolapse (Grade 2 or higher) was used as the state variable.
Conclusions: Levator hiatal area as measured by 3D translabial pelvic floor ultrasound examination is strongly associated with symptoms and clinical signs of prolapse. Based on the ROC curves that we obtained, we suggest that a hiatal area of > 25 cm(2) on Valsalva be defined as abnormal distensibility or 'ballooning' of the levator hiatus.