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Image-based simulation of urethral distensibility and flow resistance as a function of pelvic floor anatomy

Authors

  • Franklin Yao,

    1. Department of Urology, Weill Medical College of Cornell University, New York-Presbyterian Hospital, New York, New York
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  • Melissa A. Laudano,

    1. Department of Urology, Weill Medical College of Cornell University, New York-Presbyterian Hospital, New York, New York
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  • Stephan Seklehner,

    1. Department of Urology, Weill Medical College of Cornell University, New York-Presbyterian Hospital, New York, New York
    2. Department of Urology, Landesklinikum Baden-Mödling, Baden, Austria
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  • Bilal Chughtai,

    1. Department of Urology, Weill Medical College of Cornell University, New York-Presbyterian Hospital, New York, New York
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  • Richard K. Lee

    Corresponding author
    1. Department of Urology, Weill Medical College of Cornell University, New York-Presbyterian Hospital, New York, New York
    • Correspondence to: Richard K. Lee, M.D., M.B.A., Weill Cornell Medical College, Department of Urology, 425 East 61st Street, New York, NY 10065.

      E-mail: ril9010@med.cornell.edu

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  • Franklin Yao and Melissa A Laudano equally contributed to this work.
  • Christopher Chapple led the peer-review process as the Associate Editor responsible for the paper.
  • Conflict of interest: none.

Abstract

Aims

The goal of this study is to develop an image-based model of urethral distention and resistance in women with and without SUI.

Methods

A biomechanical vector force model was created to simulate the mechanical deformation of pelvic floor structures during cough and Valsalva in order to measure urethral distension and predict flow resistance patterns. Dynamic MRI images were used to create a spatial model to construct an accurate representation of tissue thickness and location, which was combined with tissue property values (MATLAB 2011a, MathWorks, Natick, MA). Spatial profiles were created to demonstrate the effects of hypermobility and tissue property variability on distensibility and flow resistance along the urethra. Sensitivity analyses were conducted to demonstrate the relationship between flow resistance and various tissue properties.

Results

The average distension for incontinent cases (3.8 mm) was significantly greater than that of continent cases (2.6 mm) (t = 3.3083, df = 8, P < 0.01), corresponding to a 70% drop in average resistance to urine flow. Sensitivity analyses demonstrated that the stiffness and contractility of the vagina and urethra had the greatest effect on continence.

Conclusions

We present a novel, 2-dimensional biomechanical model of female stress urinary incontinence (SUI) that relates the effects of various factors such as tissue elasticity, pelvic floor structure, and muscle activation. A better understanding of the pathophysiology underlying SUI has potential implications for the creation of novel targeted treatments. Neurourol. Urodynam. 34:???–???, 2015. © 2014 Wiley Periodicals, Inc.

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