Pelvic floor muscle function differs between postmenopausal women with and without stress urinary incontinence: An...

Area of Science:

• Urogynecology
• Pelvic Floor Muscle Physiology
• Biomedical Engineering

Background:

• Pelvic floor muscle (PFM) dysfunction, particularly in the urethral sphincter (US) and levator ani muscles (LAMs), is implicated in stress urinary incontinence (SUI).
• Quantifying PFM activity is essential for understanding SUI pathogenesis and guiding treatment.
• Surface electromyography (sEMG) offers a non-invasive method for PFM assessment.

Purpose of the Study:

• To evaluate the strength and activity of the US and LAMs using sEMG with a novel airbag-type stretchable/inflatable electrode array (ASEA) device.
• To assess the predictive value of ASEA-derived sEMG signals in postmenopausal women with SUI.
• To identify specific PFM components that are dysfunctional in SUI.

Main Methods:

• sEMG recordings of the US and LAMs were obtained from 67 women with SUI and 65 healthy controls.
• Measurements included resting potential, maximum voluntary contraction (MVC), tonic contraction potential (TCP), and endurance contraction potential (ECP).
• Receiver operating characteristic (ROC) curve analysis was used to determine discriminative cut-off values.

Main Results:

• Women with SUI exhibited significantly lower muscle strength and sEMG activity (MVC, TCP, ECP) in the US and LAMs compared to controls.
• ROC analysis identified specific cut-off values for the US, puborectalis, and pubococcygeus muscles with discriminative ability for SUI.
• sEMG of the iliococcygeus muscles did not significantly differ between groups.

Conclusions:

• Defects in the urethral sphincter and dysfunction of specific levator ani muscles (puborectalis, pubococcygeus) are key contributors to SUI.
• Region-specific sEMG assessment using the ASEA device can accurately identify PFM abnormalities in SUI patients.
• This approach holds promise for developing optimized and precise PFM rehabilitation strategies.