OP24.13: Is dynamic investigation of the anal sphincter complex useful for assessment of the anal sphincter complex?

Abstract

Objectives:Transperineal ultrasound can be used for investigationof anatomic abnormalities of the anal sphincter complex. Theadvantage of ultrasound is that this is a non-invasive investigationwith the possibility of performing a dynamic assessment of thepelvic floor and i.e. the anal sphincter. This study was designed todetermine if dynamic investigation is useful for the assessment ofsphincter anatomy and defectsMaterial and Methods:In a prospective observational study 126patients were included. Transperineal ultrasound was performedafter voiding in supine position acquiring 3D/4D volumes at rest andin contraction using a GE Kretz Voluson 730 Expert system. Forimaging of the anal sphincter complex a 3D micro convex transducer(RNA 5 – 9 MHz) was used. Off line analysis was performed with4D View software with the investigator blinded against the clinical data. VCI static technique was used with a slice thickness of 2 mmfor assessment of the anal sphincter complex. Measurements weretaken in the axial plane of the length of the superficial externalsphincter, total length of the anal sphincter complex and in thesagittal plane the width of the defect of the external sphincter and/orinternal sphincter.Results:32 Patients were diagnosed with an anal sphincter injury(25%), which involved either the internal sphincter, external or both.In 2 patients the external sphincter defect could not be visualized incontraction, whereas in 3 patients this defect was only visualized incontraction. For 2 patients there was also an internal defect found incontraction. The length of the external sphincter and the total lengthof the sphincter complex were significant shorter in contraction(P<0.01). The width of the defect in contraction for as well theexternal and internal sphincter was significant wider in contraction(P<0.05).Conclusions:In contraction the anal sphincter complex shortens,and defects become significant more obvious then at rest.