The use of a bedwetting alarm to assess lower urinary tract function in non-toilet-trained children and in children with spinal dysraphism.

OBJECTIVE: To describe a user-friendly voiding monitoring method based on a bedwetting alarm, and to evaluate its clinical significance as a complementary assessment of lower urinary tract function in neurogenic and non-toilet-trained children for whom standard urodynamic studies are unfeasible, technically challenging, or yield suboptimal results. STUDY DESIGN: This retrospective study included children who underwent outpatient daytime bedwetting alarm assessments during 2021-2025. An alarm sensor was placed inside a dry diaper. When the alarm was activated, the diaper was weighed, and a post-void ultrasound residual was measured. The number and volume of voids, time intervals between voids, leaks, and post-void residuals were retrieved. RESULTS: Included were 35 children (15 girls, 43%), median age 2 years (interquartile range [IQR] 1, 3.4). Twenty-six (74.5%) had neurogenic bladders, 5 (14%) had undergone bladder surgery, and 4 (11.5%) had non-neurogenic functional disorders. The reasons for the assessment were: decision-making regarding clean intermittent catheterization (CIC) following unsatisfactory urodynamic studies (n = 22, 63%), assessment of emptying after bladder/reflux surgery (n = 5, 14%), evaluation of CIC timing (n = 4, 11%), and suspicion of lower urinary tract dysfunction (n = 4, 11%). The median test duration was 4.5 h (IQR 4, 5). The assessments captured a median of 4 voids per patient (IQR 3-6), with a median maximal voided volume of 45 ml (IQR 32-121) and a median maximal time interval of 120 min (IQR 78-143). Following the findings, CIC was initiated in 12 children (34%) [all with neurogenic bladders, mean PVR/EBC ratio 0.7] and discontinued in 3 (9%) [all non-neurogenic, mean PVR/EBC ratio 0.3]. In 13 (37%), normal findings ruled out the need for further investigation. Of the 20 children with neurogenic bladders who underwent complementary bell-alarm tests after urodynamic studies, CIC was initiated in 11 (55%). DISCUSSION: While mainly limited by its retrospective nature and the small sample size, this study managed to describe the utility of the bell assessment for several urologic conditions and clinical questions. CONCLUSIONS: The outpatient bell-alarm assessment can complement evaluations of lower urinary tract function, and guide treatment decisions in pediatric populations with various conditions.