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High-frequency micro-ultrasound: A novel method to assess external urethral sphincter function in rats following simulated birth injury

Authors

  • Lukman Hakim,

    Corresponding author
    1. Laboratory of Experimental Urology, Department of Development and Regeneration, KU Leuven, Leuven, Belgium
    2. Department of Urology, Airlangga University School of Medicine/Dr. Soetomo General Hospital, Surabaya, Indonesia
    • Correspondence to: Lukman Hakim, M.D., M.H.A., Laboratory of Experimental Urology, Department of Development and Regeneration, KU Leuven, Leuven, Belgium. E-mail: lukman0908@yahoo.com

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  • Masayuki Endo,

    1. Pelvic Floor Unit, Department of Development and Regeneration, KU Leuven, Leuven, Belgium
    2. Research Unit Bio-Implants, Bio-Mechanics and Tissue Engineering, Department Development and Regeneration, KU Leuven, Leuven, Belgium
    3. Faculty of Medicine, Interdepartmental Center for Surgical Technologies, KU Leuven, Leuven, Belgium
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  • Andrew Feola,

    1. Research Unit Bio-Implants, Bio-Mechanics and Tissue Engineering, Department Development and Regeneration, KU Leuven, Leuven, Belgium
    2. Faculty of Medicine, Interdepartmental Center for Surgical Technologies, KU Leuven, Leuven, Belgium
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  • Doddy M. Soebadi,

    1. Department of Urology, Airlangga University School of Medicine/Dr. Soetomo General Hospital, Surabaya, Indonesia
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  • Jan Deprest,

    1. Pelvic Floor Unit, Department of Development and Regeneration, KU Leuven, Leuven, Belgium
    2. Research Unit Bio-Implants, Bio-Mechanics and Tissue Engineering, Department Development and Regeneration, KU Leuven, Leuven, Belgium
    3. Faculty of Medicine, Interdepartmental Center for Surgical Technologies, KU Leuven, Leuven, Belgium
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  • Dirk De Ridder,

    1. Laboratory of Experimental Urology, Department of Development and Regeneration, KU Leuven, Leuven, Belgium
    2. Pelvic Floor Unit, Department of Development and Regeneration, KU Leuven, Leuven, Belgium
    3. Faculty of Medicine, Interdepartmental Center for Surgical Technologies, KU Leuven, Leuven, Belgium
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  • Maarten Albersen,

    1. Laboratory of Experimental Urology, Department of Development and Regeneration, KU Leuven, Leuven, Belgium
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  • Frank Van der Aa

    1. Laboratory of Experimental Urology, Department of Development and Regeneration, KU Leuven, Leuven, Belgium
    2. Pelvic Floor Unit, Department of Development and Regeneration, KU Leuven, Leuven, Belgium
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  • Karl-Erik Andersson led the peer-review process as the Associate Editor responsible for the paper.
  • Conflict of interest: None of the authors have conflict of interests, except Doddy M. Soebadi who is involve in trials and receives speaker honorarium from Astellas Pharma, Glaxo Smith Kline, Bayer, and Pfizer.

Abstract

Aims

We evaluated external urethral sphincter (EUS) function using high-frequency micro-ultrasound (US) in rats that were either uninjured (Control, C) or underwent vaginal distension (VD) as a substitute for vaginal birth injury induced stress urinary incontinence (SUI).

Methods

Thirteen female nulliparous Sprague–Dawley rats of 12 weeks were divided into two groups, either C (n = 6) or VD (n = 7). Vaginal balloon distension was performed under pentobarbital anesthesia for 4 hours. Five days after the injury, all animals underwent US assessment of the urethra during high-rate bladder filling and urine leakage/voiding. Urinary leakage, the presence, absence, and pattern of EUS bursting during the voiding phase were registered, and pre-determined parameters of intercontraction interval (ICI), length of contraction (LOC), and rate of contraction (ROC) were registered.

Results

Our ultrasound findings consistently showed the presence of rhythmic EUS bursting in all of the C rats (6/6), which were absent in all VD rats (0/7). The mean of ROC, ICI, and LOC in C group were 3.02 ± 0.12 contractions/sec, 471.43 ± 17.9 msec, and 103.41 ± 3.28 msec, respectively.

Conclusions

Pre-determined parameters of LOC, ICI, and ROC during US provide objective and measurable data on EUS function. US showed the total disappearance of EUS bursting in the VD group as compared to the C group. These results indicate that ultrasound testing may become a valuable non-invasive tool in future translational studies to investigate SUI/urethral function in rat models. Neurourol. Urodynam. 34:264–269, 2015. © 2014 Wiley Periodicals, Inc.

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