Static and Dynamic Ultrasound Imaging to Visualize the Bladder, Bladder Neck, Urethra, and Pelvic Floor in Children with Daytime Incontinence.

Abstract

Daytime urinary incontinence is a major health care problem occurring in 15 and 5% of 4-year-old and 9.5-year-old children, respectively (1, 2). Continence comes from an intrinsic interaction between anatomical and functional factors. Ascertaining the cause of incontinence remains a challenging task and is often derived from a complex of features. A few principal causes are urge in overactive bladders, voiding postponement, dysfunctional voiding, an underactive bladder, and stress incontinence. Mostly no structural, neurogenic, or other organic cause can be found in children with daytime urinary incontinence. Bladder neck competence is an important factor in achieving continence. The following basic outlet functions are known: closure during urine storage with increased closure during exercise or bladder filling (the guarding reflex), sustained opening when voiding, and transient opening for males when ejaculating (3, 4). Standardization of terms as well as diagnostic and therapeutic abilities have been improved by the efforts done by dedicated institutions (5). Essentially non-invasive screening is standardized consisting of history-taking, clinical examination, urinalysis, uroflowmetry, ultrasound (US) (including post-void residual volume), voiding, and stool diary and pressure-flow studies (1, 6, 7). Initial management requires basic diagnostic tests. Treatment is mostly conservative and empiric (lifestyle interventions, physiotherapy, and pharmacotherapy). More elaborate assessment is required when primary therapy fails, diagnosis is unclear, or symptoms and signs are complex/severe (8). More (and novel) diagnostic tools to pinpoint the reason for incontinence need to be evaluated. After all, only the right diagnosis can lead to appropriate therapy or even surgery. Ultrasound can be a valuable and patient friendly additive to physical examination. Already, it is the primary imaging tool in children with urological problems. Physical examination can be stressful especially for the pediatric population. US is well tolerated, not expensive, widely available, not invasive, and needs no radiation (9). Nowadays, a portable handheld pocket US machine is available. Transperineal US provides accurate visualization, both static and dynamic. It provides anatomical and even functional information. Imaging the bladder neck is superior to transabdominal US due to the bony pubic landmark as a reference point (10). Also it seems better than cystoscopy since it provides an overview of the bladder neck and surrounding tissue instead of the rather limited internal view. Furthermore, US requires no anesthesia, making the situation more physiological enabling dynamic testing. This article focuses on US imaging of the lower urinary tract for patients with daytime incontinence. It provides practical guidance on how to perform transabdominal and transperineal US. We combine current insights from the literature with our clinical practice. We like to promote the use of US for physicians specialized in urinary incontinence.