What improvements in levator ani motor function lead to improvement in stress urinary incontinence signs and symptoms in females?

Abstract

The objectives were to determine whether levator ani muscle (LAM) motor function is associated with female stress urinary incontinence (SUI) severity, and whether changes in LAM motor function induced through pelvic floor muscle training (PFMT) are associated with improvements in SUI signs and symptoms. Pelvic morphology and LAM function were evaluated using ultrasound imaging and manual palpation using the elements of the PERFECT Scheme (Power, Endurance, Repetitions, Fast contractions, Elevation, Co-contraction and Timing) before and after women with SUI underwent a 12-week PFMT intervention. SUI severity was determined subjectively (ICIQ-FLUTS-UI) and objectively (30-min pad test [30MPT]). At baseline (n = 97), less leakage on the 30MPT was weakly associated with higher bladder neck position (ρs = -0.209,p = 0.044), yet with lower LAM function based on the PERFECT Scheme (overall score: ρs = 0.206, p = 0.043; repeated maximum voluntary contractions (MVCs): ρs = 0.203, p = 0.046; power/motor control: ρs = 0.214, p = 0.035). Lower symptom severity (ICIQ-FLUTS-UI) was associated with observed perineal lift during coughing (U = 34.000; p = 0.042). All measures of SUI severity and LAM function were significantly improved after PFMT intervention. Greater improvements in bladder neck elevation during MVC (ρs = -0.261, p = 0.027) and greater reductions in levator plate length during MVC (ρs = 0.292, p = 0.016) were weakly associated with greater reductions in leakage (30MPT), the latter also being associated with more improvement symptoms (ICIQ-FLUTS-UI; ρs = 0.238, p = 0.041). Greater improvement in the ability to repeat MVCs (ρs = 0.303, p = 0.009) was weakly associated with smaller improvements in symptoms (ICIQ-FLUTS-UI). Improvements in bladder neck support and elevation show weak associations with improvement in SUI signs and symptoms. LAM function as measured by the PERFECT Scheme is not associated with SUI severity in women, and improvements in LAM function when measured by the PERFECT Scheme are not associated with improvements in SUI signs and symptoms.