Ultrasound-estimation of the bladder wall thickness in children with spina bifida occulta

Abstract

Objective The objective of the study was to correlate ultrasonographic bladder wall thickness measurement(BWT) with urodynamic studies in children with spina bifida occulta. Methods The study included 22 spina bifida occulta (SBO) patients (aged 8. 8 ± 4. 9 years)with upper urinary tract dilation (UUTD) and 29 SBO patients (aged 9. 3 ± 5.3 years) without UUTD. Urodynamic studies were performed. Maximal detrusor pressure during filling or at leak, maximal amplitude detrusor overactivity and detrusor leak point pressure were recorded. After filling of 60% of expected bladder capacity(EBC), the BWT was measured via suprapubic ultrasound. UUTD was diagnosed with ultrasound. The differences in BWT between the 2 groups were analyzed. The correlation between BWT and urodynamic parameters was studied. The receiver operator characteristic (ROC) curve was used to find the association between the urodynamic parameters and BWT. Results There was a significant difference between bladder wall thickness in children with and without UUTD (3. 4 ± 0. 25 mm vs. 2. 5± 0. 45) mm, P＜0. 05). The bladder wall thickness significantly correlated with the maximal amplitude detrusor overactivity, the detrusor leak point pressure and the maximal detrusor pressure during filling(r = 0. 85、0. 87 and 0. 91 ). As a prediction of UUTD, BWT greater than 3. 0 mm had specificity of 79. 4% and sensitivity of 90. 9%, a positive predictive value of 76. 9%, a negative predictive value of 92.0%. ROC analysis revealed that BWT had a high predictive value for unfavorable urodynamic patterns, with an area under the curve of 0. 929. Conclusions BWT can be used to predict UUTD. BWT ＞3. 0 mm appears to be a useful predictor of UUTD in children with spina bifida occulta. Key words: Ultrasonography; Upper urinary tract deterioration; Spina bifida occulta; Bladder wall thickness