Positional changes in voiding dynamics of children with non-neurogenic bladder dysfunction

To investigate the effect of certain positions on voiding dynamics in children with non-neurogenic bladder dysfunction.

A total of 29 patients (10 male, 19 female) with non-neurogenic overactive bladder were enrolled. None of the patients had voiding phase dysfunction. Male patients were told to urinate in three positions (sitting, squatting, standing). Female patients did not void while standing. During voiding, maximum urinary flow rate (Qmax), detrusor pressure at maximal flow (Pdet-Qmax), and intra-abdominal pressure at maximal flow (Pabd-Qmax) were recorded. After voiding in one position, the bladder was re-distended. The same procedures were repeated for the three different positions. Then patients were told to perform three drinking-voiding cycles without the catheter in place. After recording Qmax, residual urine was measured with ultrasonography. The differences between these parameters were analyzed.

The mean (+/- standard deviation) patient age was 11.10 +/- 2.94 years (range, 6-16 years). In girls, the mean Pdet-Qmax value in the sitting and squatting positions was 43.11 +/- 16.74 cm H(2)O and 35.21 +/- 10.67 cm H(2)O, respectively (P = .028). Girls voided with a significantly higher Qmax in sitting and squatting positions than boys, regardless of the presence of a catheter. The mean Pdet-Qmax value in the squatting position was 59.20 +/- 20.45 cm H(2)O in boys and 35.21 +/- 10.67 cm H(2)O in girls. The presence of a catheter significantly lowered mean maximal urinary flow rates in sitting and squatting positions.

This is the first study to demonstrate the effect of voiding positions on pressure flow study results in children. Our results show that voiding dynamics are influenced by different voiding positions in children with non-neurogenic bladder dysfunction.