The correlation between bladder volume wall index and the pattern of uroflowmetry/external sphincter electromyography in children with lower urinary tract malfunction

Abstract

Objective: To evaluate the relationship between bladder volume wall index (BVWI) and the pattern of uroflowmetry in children with lower urinary tract malfunction.

Patients & methods: 91 children aged 4-15 years with history of bladder dysfunction and 59 age/sex-matched healthy children with negative urine culture in previous month were enrolled. Uroflowmetry and kidney and bladder sonography were performed in all children. BVWI was measured by dividing maximum bladder volume index by mean bladder thickness. It was expressed as percentage by dividing calculated BVWI by expected BVWI, and values between 70% and 130% were presumed normal. Urodynamic study was done in symptomatic cases.

Results: The bladder was thick (<70%) in 39 (28 cases, 11 controls) and thin (>130%) in 35 (18 cases, 17 controls) (P > 0.05). Uroflowmetry was abnormal in 82 (61 cases, 21 controls) (P < 0.05). Severe sphincter dyssynergia was detected in 47% of cases compared with 20% of controls (P < 0.05).There was no relationship between BVWI and uroflowmetry in cases or in controls (P > 0.05). The median post-void residual urine was not statistically different between the groups (20 vs 12.3 ml) (P > 0.05). When both bladder sonography and uroflowmetry were abnormal, they had an association with abnormal urodynamics (P < 0.05).

Conclusion: Among children with lower urinary tract dysfunction, the pattern of uroflowmetry could not be predicted from the BVWI, but in cases with combined abnormal bladder sonography and uroflowmetry results, there was a significant association with an abnormal urodynamic study.