Long-Term Urethral Function Measured by Uroflowmetry After Hypospadias Surgery: Comparison with an Age Matched Control

Abstract

Long-term outcomes of hypospadias surgery, particularly urinary function, have not been examined thoroughly. Uroflowmetry can be used to evaluate long-term functional outcomes by assessing flow shape and the rate of micturition. We assessed urethral function using uroflowmetry in adolescents after undergoing hypospadias repair in infancy and compared this with age matched controls. After human research ethics committee approval (HREC 28111A), 17 boys 13 to 15 years old with no history of urological or neurological disorders underwent uroflowmetry (65 separate voids) to determine standard values for boys of this age. Then 60 boys age 13 to 15 years who had undergone treatment for hypospadias in early infancy were seen for long-term followup and underwent uroflow assessment. Standard urinary flow rates were established in the 13 to 15-year-old control group and represented on a nomogram. In the boys who underwent hypospadias surgery the urine flow rates were significantly lower compared to the control nomogram (p <0.0001), with half the patients having uroflow rates below 1 SD from the control mean but without symptoms. Boys with significant preoperative chordee were more likely to have poorer urinary flow (p <0.04). A poor urinary flow rate also was significantly associated with post-void residual bladder volume (p <0.03). There was no correlation with original meatal location, number of operations, presence of postoperative complications, current anatomy and lower urinary tract symptoms (eg post-void dribble, hesitancy, incontinence). At long-term followup after hypospadias surgery urinary flow rates were significantly lower compared to age matched controls but still fell within the normal range. In the hypospadias cohort there was no significant association with lower urinary tract symptoms and poor urinary flow. Detection of poor urinary flow may indicate incomplete bladder emptying. The presence of severe chordee preoperatively is a significant risk factor for poor urinary flow rates on long-term followup.