Uroflowmetry is a viable surrogate for urethroscopy in evaluation of anatomical success following urethroplasty

Abstract

Objectives: This study aimed to investigate the utility of uroflowmetry in predicting anatomical success following urethroplasty based on real-world clinical data. Methods: Data from 100 male patients who underwent urethroplasty for urethral strictures at our institute were analyzed. Postoperative anatomical success was determined as the passage of a 16.2 Fr flexible endoscope after approximately 4 months following the procedure. Sensitivity and specificity of the maximal flow rate (Qmax), average flow rate (Qave), and Qmax − Qave for anatomical success were determined, along with receiver operating characteristic analysis. The optimal cutoff was set using Youden's index. Results: Anatomical success was observed in 67%. Voided volumes in the success and failure groups were equivalent: 252 ± 121 versus 242 ± 91 ml, respectively. In 18 cases, voided volumes were <150 ml. Parameters of uroflowmetry were all significantly higher in the anatomical success group when compared to those in the failure group: the mean value of Qmax was 26.1 versus 15.0 ml/s; Qave, 14.2 versus 9.1 ml/s; and Qmax − Qave, 11.9 versus 5.9 ml/s, respectively (p < 0.0001 for each parameter). The area under the curve was 0.8082 for Qmax, 0.7727 for Qave, and 0.8186 for Qmax − Qave. Optimal cutoff values for Qmax and Qmax − Qave were 20 and 6 ml/s, which predicted anatomical success with 86% and 87% positive predictive value, respectively. Conclusion: This analysis presents statistically valid cutoffs by which uroflowmetry can be used as a viable surrogate of anatomical success following urethroplasty in clinical practice.