Myotonometry has recently been used to evaluate pelvic floor muscle properties [1]. Muscle mechanical properties (MMPs) have been used as a marker to determine the clinical effects of exercises in some situations in women health [2], but there is little information regarding the MMPs in stress urinary incontinence (SUI). The most common type of incontinence in women, exceeding 60% of the total cases, is SUI [2]. There are no data on the status of lumbopelvic tone or its relationship with other variables in SUI. Thus, this study aimed to determine whether lumbopelvic MMPs are different in women with SUI compared to healthy ones.

This is a cross-sectional study, which included women aged 18-60 years, SUI diagnosed (cases) and matched healthy controls. Sociodemographic and clinical data were collected. The MMPs, that is, Tone (Hz); biomechanical properties (Stiffness (N/m) and logarithmic Decrement, which is the inverse of the elasticity) and viscoelastic properties (Relaxation (ms) and Creep (Deborah Number -De-), which characterizes fluidity), were evaluated on both sides of the central perineal body for the perineal muscles, and on the erector spinae at 2.5 cm to the right and left of the L5 vertebra for lumbar muscles. Unpaired Student t-tests were applied to identify between groups differences in MMPs.

A total sample of 44 women with SUI (34.67 ± 13.47 years old) and 50 healthy women (35.24 ± 14.72 years old) was analyzed. All MMPs of the pelvic floor (PF), except the Stiffness, differed between groups. Thus, Tone (mean difference (MD)=1.26, 95% confidence interval (95%CI)=0.59,1.94) and Decrement (MD=0.07, 95%CI=0.01,0.14) were higher in the healthy individuals, but Relaxation (MD=-1.14, 95%CI=-2.01,-0.28) and Creep (MD=-0.05, 95%CI=-0.09,-0.02) were higher in SUI individuals. Regarding Lumbar muscles, only the Decrement was different between groups (MD=-0.20, 95%CI=-0.35,-0.05), with healthy women showing more elasticity than women with SUI.

Lumbopelvic MMPs are affected in women with SUI. Women with SUI had less tone, which could predispose to a delayed and worse muscle contraction, while continent women produce higher activity of pelvic floor muscles (PFM). Lumbar MMPs of women with SUI had less elasticity. In this sense, the relationships between IU, pain and stiffness in the pelvic area, and posture justify the necessity of a broad assessment in SUI, even for treatment purposes [3].

Pelvic floor tone increased, while elasticity and viscoelastic properties and lumbar elasticity are decreased in SUI. The evaluation of lumbopelvic MMPs can be applied in clinical settings due to their innocuousness and applicability.

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Ng SF, Lok MK, Pang SM, et al. Stress Urinary Incontinence in Younger Women in Primary Care: Prevalence and Opportunistic Intervention. J Womens Health 2014;23(1):65–68; doi: 10.1089/jwh.2013.4382.
Proulx L, Brizzolara K, Thompson M, et al. Women with Chronic Pelvic Pain Demonstrate Increased Lumbopelvic Muscle Stiffness Compared to Asymptomatic Controls. J Womens Health 2023;32(2):239–247.

Continence 12S (2024) 101626
DOI: 10.1016/j.cont.2024.101626