PD01-12 A FLUID-STRUCTURE INTERACTION SIMULATION OF FECAL INCONTINENCE

Abstract

You have accessJournal of UrologyUrodynamics/Lower Urinary Tract Dysfunction/Female Pelvic Medicine: Incontinence: Evaluation (Urodynamic Testing)1 Apr 2016PD01-12 A FLUID-STRUCTURE INTERACTION SIMULATION OF FECAL INCONTINENCE Yun Peng, Leila Neshatian, Rose Khavari, Timothy Boone, and Yingchun Zhang Yun PengYun Peng More articles by this author , Leila NeshatianLeila Neshatian More articles by this author , Rose KhavariRose Khavari More articles by this author , Timothy BooneTimothy Boone More articles by this author , and Yingchun ZhangYingchun Zhang More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2016.02.2032AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Fecal incontinence (FI) is a common symptom with a prevalence of 7-15%. We employed a computational modeling approach to study the mechanism of fecal continence, which has not been fully understood yet. METHODS A previous subject specific pelvic model was employed, while the internal and external anal sphincters (IAS/EAS) were newly included by revisiting the magnetic resonance images (Fig 1a). The sphincters and other soft tissues were modeled as elastic solids in the model, and the gravity was applied. Biomechanical analysis were conducted using Abaqus (Providence, Rhode Island) Explicit Solver. The motion of the stool was described using the smoothed particle hydrodynamics (SPH) method, which is based on a clever discretization technique. The “particles” shown in Fig 1 should be interpreted as displayed interpolation points of a continuum medium rather than isolated mass points. SPH is a well-established computational technique in many hydrodynamics applications, and can be used to accurately describe the fluid nature of the stool that can be difficult using traditional computation approaches. Three tests were performed in this study. Test 1: only the effect of gravity was considered; Test 2: the resting anorectal status was simulated by applying a pressure of 88 mmHg on the surface of the IAS. Test 3: based on test 2, a Valsalva maneuver was simulated by further applying an intraabdominal pressure (IAP) of 100cmH2O to the bodyfill. Incontinence was confirmed if the stool reached to the outer anus opening. RESULTS In test 1, the stool leaked due to gravity as no closing pressure was applied (Fig 1b). In test 2, the anus was closed because of the closing pressure applied on the IAS. Continence was successfully maintained (Fig 1c). In test 3, the pelvic floor deformations were obvious because of the increased IAP. The incontinence was again seen as the closing pressure was not enough to hold the stool under the increased IAP (Fig 1d), indicating that additional closing pressure from EAS may be necessary for maintaining continence during Valsalva maneuver. CONCLUSIONS Computational modeling is a useful tool for studying FI. The stool-anorectum interaction can be well described by the SPH method. Future studies will consider the efforts of the EAS and the puborectalis muscle. © 2016FiguresReferencesRelatedDetails Volume 195Issue 4SApril 2016Page: e50 Advertisement Copyright & Permissions© 2016MetricsAuthor Information Yun Peng More articles by this author Leila Neshatian More articles by this author Rose Khavari More articles by this author Timothy Boone More articles by this author Yingchun Zhang More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...