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123 - KINEMATIC PROFILES OF URETHRAL MORPHOLOGY VERSUS MOBILITY DURING PELVIC FLOOR MUSCLE MAXIMUM VOLUNTARY CONTRACTIONS

123

KINEMATIC PROFILES OF URETHRALMORPHOLOGY VERSUS MOBILITY DURING PELVIC FLOOR MUSCLE MAXIMUMVOLUNTARY CONTRACTIONS

C. S. CZYRNYJ1, L. B.MCLEAN 2;
1Mechanical Engineering, Univ. ofOttawa, Ottawa, Canada, 2Univ. of Ottawa, Ottawa, Canada.

Introduction: Urethralhypermobility is thought to contribute to the development of stressurinary incontinence (SUI) in women [1]. We have developed the UROKINsoftware, a robust semi-automated program that computes kinematicprofiles of urogenital landmarks from transperineal ultrasound (TPUS)images acquired during functional tasks [2].
Objective: Asa proof of concept, UROKIN was used to determine whether changes inurethral morphology or mobility during maximum voluntary PFMcontractions (MVCs) differ between women with and without SUI.
Methods: The protocol was approved by the institutionalresearch ethics board and twenty women with SUI and ten women withoutSUI provided written informed consent prior to participating. As partof a larger protocol, mid-sagittal TPUS images were acquired, using aGE Voluson-i (GE Healthcare, Canada) in B-mode using a 3Dcurvilinear probe (8-4MHz) while women performed three repetitions ofa PFM MVC in supine. Using the UROKIN software [3], the levator plateline (LPL), anterior and posterior urethra, and bladder neck (BN)were identified in each frame of each MVC video. A urethral midline,between the anterior and posterior urethral walls (from the LPL tothe BN), was divided into six equidistant points. Time normalizedkinematic curves of the urethral midline length, the antero-posteriordiameter of the urethral lumen (APUL), and urethral midlinedisplacement were ensemble averaged across groups. Mean APUL at allpoints and mean urethral length were compared between groups using aone-way ANOVA (α=0.05).
Results: Women with and withoutSUI did not differ in age (47±2 vs. 40±4 years) or body mass index(26±1 kg/m2 vs. 23±1 kg/m2). Womenwith SUI exhibited less urethral motion during MVC than those withoutSUI (Figure 1). There was no significant difference in thelength of the urethral midline between groups, however women with SUIexhibited larger mean APUL at all points along the urethral midline(p<0.01) except at the bladder neck (p>0.05). In both groups,urethral length increased slightly over the course of the MVC (Figure2).


Figure 1. Ensemble average (mean±standard error) cranio-caudal (A, B, C) and antero-posterior(D,E,F) urethral displacements, in women with and without stressurinary incontinence (SUI), during maximum voluntary pelvic floormuscle contraction at the levator plate (A,D), mid-way between thelevator plate and the bladder neck (B,E), and bladder neck (C,F).


Figure 2. Ensemble averagecurves of the antero-posterior diameter of the urethral lumen, at thelevator plate line (A) and at the bladder neck (B), and for urethrallength (C) measured during maximum voluntary pelvic floor musclecontraction in women with and without stress urinary incontinence(SUI).

Conclusions: Sagittal plane ultrasoundimages acquired during an MVC task revealed significantdifferences in urethral kinematics and morphology between women withand without SUI. UROKIN may have the capacity to provide robustinformation on the pathomechanics that underpin SUI inwomen.
References: 1. Ultrasound Obstet Gynecol.2010;36:507-511. 2. 2016 IEEE Eng Med Biol Soc ISC. 2016;1-4