Advances in basic science methodologies for clinical diagnosis in female stress urinary incontinence

Abstract

We provide an overview of advanced imaging techniques currently being explored to gain greater understanding of the complexity of stress urinary incontinence (SUI) through better definition of structural anatomic data. Two methods of imaging and analysis are detailed for SUI with or without prolapse: 1) open magnetic resonance imaging (MRI) with or without the use of reference lines; and 2) 3D reconstruction of the pelvis using MRI. An additional innovative method of assessment includes the use of near infrared spectroscopy (NIRS), which uses non-invasive photonics in a vaginal speculum to objectively evaluate pelvic floor muscle (PFM) function as it relates to SUI pathology. Advantages and disadvantages of these techniques are described. The recent innovation of open-configuration magnetic resonance imaging (MRO) allows images to be captured in sitting and standing positions, which better simulates states that correlate with urinary leakage and can be further enhanced with 3D reconstruction. By detecting direct changes in oxygenated muscle tissue, the NIRS vaginal speculum is able to provide insight into how the oxidative capacity of the PFM influences SUI. The small number of units able to provide patient evaluation using these techniques and their cost and relative complexity are major considerations, but if such imaging can optimize diagnosis, treatment allocation, and selection for surgery enhanced imaging techniques may prove to be a worthwhile and cost-effective strategy for assessing and treating SUI. IntroductionAdvances in the diagnosis and treatment of female stress urinary incontinence (SUI) are being aided by the use of emerging technologies that offer greater understanding of the basic science underlying bladder disease.1 This is relevant given that female SUI affects 32-64% 2 of the female population and that 11.1% will need to undergo treatment or require surgery in their lifetime.3 In addition to providing novel insights on the causal etiology, new technologies offer elements able to enhance diagnosis and tools relevant to optimizing therapy for a large number of women worldwide. 4Pregnancy and childbirth are the important causes of pelvic floor injury. Subpopulations of patients are recognized within the spectrum of SUI. SUI can be observed in nulliparous women 4.7% of the time. 4 During pregnancy SUI is reported in up to 50% of women, and additional insults to the pelvic floor are known to occur during labour and delivery. 5Epidemiological studies have identified elements related to labour and delivery that influence the frequency of symptoms; however, it is still unclear how much pregnancy contributes to the pathology, whether the predominant effects occur during labour and delivery, and what is the relevance of other risk factors, e.g., maternal age, body weight, genetics, and lifestyle. 4 Currently, it is believed that partial denervation of the pelvic floor and lineal injury to pelvic floor muscles and connective tissue are caused by mechanical and hormonal changes during pregnancy...