The role of two- and three-dimensional dynamic ultrasonography in pelvic organ prolapse

The assessment of pelvic organ prolapse has to date been limited to the clinical evaluation of surface anatomy. This is clearly insufficient. As a result, imaging of pelvic floor function and anatomy is moving from the fringes to the mainstream of obstetrics and gynecology. This is mainly due to the realization that pelvic floor trauma in labor is common, generally overlooked, and a major factor in the causation of pelvic organ prolapse. Modern imaging methods such as magnetic resonance and 3-dimensional ultrasonography have enabled us to diagnose such abnormalities reliably and accurately, most commonly in the form of an avulsion of the puborectalis muscle off its insertion on the os pubis. However, ultrasonography has other advantages in the assessment of pelvic organ prolapse, most notably in the differential diagnosis of posterior compartment prolapse, which can be due to at least 5 different conditions. In this review I will try to summarize the methods of prolapse and pelvic floor assessment by translabial ultrasonography and to describe the most common abnormalities and their consequences. This article will not deal with magnetic resonance imaging because I consider this technology to be of limited clinical utility due to technical restrictions, expense, and access issues.