Reliability of dynamometric passive properties of the pelvic floor muscles in postmenopausal women with stress urinary incontinence.
The passive properties of the pelvic floor muscles (PFM) might play a role in stress urinary incontinence (SUI) pathophysiology.


OBJECTIVE
To investigate the test-retest reliability of the dynamometric passive properties of the PFM in postmenopausal SUI women.


METHODS
Thirty-two SUI postmenopausal women were convened to two sessions 2 weeks apart. In each session, the measurements were repeated twice. The pelvic floor musculature was evaluated in four different conditions: (1) forces recorded at minimal aperture (initial passive resistance); (2) passive resistance at maximal aperture; (3) five lengthening and shortening cycles (Forces and passive elastic stiffness (PES) were evaluated at different vaginal apertures. Hysteresis was also calculated.); (4) Percentage of passive resistance loss after 1 min of sustained stretching was computed. The generalizability theory was used to calculate two reliability estimates, the dependability indices (Phi) and the standard error of measurement (SEM), for one session involving one measurement or the mean of two measurements.


RESULTS
Overall, the reliability of the passive properties was good with indices of dependability of 0.75-0.93. The SEMs for forces and PES were 0.24-0.67 N and 0.03-0.10 N/mm, respectively, for mean, maximal and 20-mm apertures, representing an error between 13% and 23%. Passive forces at minimal aperture showed lower reliability (Phi = 0.51-0.57) compared with other vaginal openings. The aperture at a common force of 0.5 N was the only parameter demonstrating a poor reliability (Phi = 0.35).


CONCLUSIONS
This new approach for assessing PFM passive properties showed enough reliability for highly recommending its inclusion in the PFM assessment of SUI postmenopausal women.
School of Rehabilitation, Faculty of Medicine, University of Montreal, Québec, Canada. melanie.m.morin@usherbrooke.ca
Mélanie
M
Morin
Denis
D
Gravel
Daniel
D
Bourbonnais
Chantale
C
Dumoulin
Stéphane
S
Ouellet
D003950:Diagnostic Techniques, Urological / Q000295:instrumentation; D004548:Elasticity; D005260:Female; D006801:Humans; D008875:Middle Aged; D009119:Muscle Contraction; D053580:Muscle Strength; D053581:Muscle Strength Dynamometer; D017773:Pelvic Floor / Q000503:physiopathology*; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D014549:Urinary Incontinence / Q000175:diagnosis* / Q000503:physiopathology*