Four-hour voiding observations detect neurogenic lower urinary tract dysfunction in neonates with anorectal malformation

Abstract

Neurogenic lower urinary tract dysfunction (LUTD) has been reported in 20-50% of children with anorectal malformations (ARM). As neurogenic LUTD represents an inherent risk of renal deterioration and urinary tract infections, an early diagnosis is important. The gold standard for evaluating neurogenic LUTD involves invasive urodynamic testing but a useful addition should be an easy-to-perform, non-invasive method of screening. In this study, we evaluate non-invasive 4h voiding observations as a screening method for neurogenic LUTD in ARM children. Thirty-four patients with ARM, excluding those with perineal fistulas, were evaluated using both 4h voiding observation and urodynamic testing before and after posterior sagittal anorectoplasty (PSARP) at median ages of 0.3 and 1.1 years. In the urodynamic assessment, the gold standard for neurogenic LUTD, nine children received the diagnosis, eight innate and one post-surgery. Five boys with a high urethral fistula and anomalies of the spinal cord had urodynamically diagnosed neurogenic LUTD, a dysfunction also identified in the 4h voiding observations. The pattern was characterised both by an increase in the number of voiding and the number of interrupted voiding, urinary leakage and elevated residual urine (Figure). In three girls with a vestibular fistula and tethered cord, an urodynamic investigation identified suspected mild neurogenic LUTD. In the voiding observations, an abnormal voiding pattern was not as obvious in the girls as in the five males. One girl with cloaca showed signs of postsurgical denervation damage, which was easily identified in the 4h voiding observations (high capacity and elevated residual urine). In the present study, gender differences in the severity of dysfunction reflected in the free voiding pattern in infants with ARM and neurogenic LUTD is probably the result of the different underlying causes of neurogenic LUTD in boys and girls. Boys with the condition have a congenital malformation of the caudal part of the spinal cord and girls a tethering of the cord. The most obvious limitation of the study was the low number of patients. Despite this, we consider the results worth reporting, since we found that results in the free voiding observations effectively confirmed what was established in the urodynamic investigations. In pre-PSARP patients, 4h voiding observations can be used to screen for severe neurogenic LUTD requiring attention and treatment. When post-surgical denervation is suspected, the voiding observation is also a good method for indicating the diagnosis.