Re: Warping of the levator hiatus: how significant is it? H. P. Dietz, I. Severino, I. Kamisan Atan, K. L. Shek and R. Guzman Rojas. Ultrasound Obstet Gynecol 2016; 48: 239-242.

Abstract

Linked Comment: Ultrasound Obstet Gynecol 2016; 48: 239–242 The pelvic floor is one of the most complex regions in the human body, where one organ can influence considerably the anatomy and function of other structures. Furthermore, it is generally assessed and treated by various specialties, each tending to deal separately with an individual compartment, rather than the pelvic floor being treated holistically as one system. Imaging and quantification of abnormalities can be performed by various techniques, with ultrasound playing a major role due to its obvious advantages in comparison to magnetic resonance imaging or proctography. However, ‘ultrasound’ covers a variety of anatomical access points (transperineal, endovaginal, endoanal ultrasound imaging) as well as different ultrasound transducers, types of acquisition, frequencies and technologies, including two-dimensional (2D), three-dimensional (3D) and four-dimensional (4D) ultrasound. One of the most efficient techniques for pelvic floor assessment, 3D/4D transperineal ultrasound (TPUS), was used by Dietz et al. for their retrospective analysis of 190 patients with pelvic organ prolapse (POP). The examinations were performed by 10 different trainees, who demonstrated high repeatability of the method. They assessed levator hiatal warping, defined as lateral and caudal distension with deformation of the hiatus, and found a clear but minor craniocaudal difference in the location of the minimal distances in mid-sagittal and coronal planes (mean, –1.26 (range, –6.7 to 4.6) mm, P < 0.001), supporting the determination of hiatal area in a rendered volume of 1–2 cm in depth. The paper describes in considerable detail the ultrasound methodology used and will therefore be very helpful for introducing the method to others who deal with pelvic-floor patients. It indicates that 3D/4D TPUS allows visualization of a non-Euclidian shape of the hiatus, both at rest and during Valsalva, showing this technology to be superior in comparison to the more commonly used 2D ultrasound. Of course, using a 2D TPUS approach has indisputable advantages, particularly in the assessment of dynamic studies; however, 3D/4D technology delivers more information. The authors also reiterate that other options, such as volume contrast imaging, render mode and tomographic imaging, may be very helpful in clinical practice. The main limitation of the paper is that it seems not to have any real clinical impact for the diagnosis and treatment of POP patients, insomuch as the information about hiatal deformation would not influence the choice of treatment method. It does, however, make an important contribution to our knowledge regarding the course of POP, highlighting a new aspect of anatomical change, hiatal warping, which can be visualized with ultrasound. It also describes, step by step, the methodology of pelvic floor TPUS, using various currently available imaging options and showing how they can be used, what anatomical and functional details can be visualized and in which pathologies they may play significant roles, thereby showing that TPUS should be considered as a reliable method for complete assessment of pelvic floor pathology.