Critical Analysis of the Use of Uroflowmetry for Urethral Stricture Disease Surveillance

Abstract

To critically evaluate the use of uroflowmetry (UF) in a large urethral stricture disease cohort as a means to monitor for stricture recurrence. This study included men that underwent anterior urethroplasty and completed a study-specific follow-up protocol. Pre- and postoperative UF studies of men found to have cystoscopic recurrence were compared to UF studies from successful repairs. UF components of interest included maximum flow rate (Qm), average flow rate (Qa), and voided volume, in addition to the novel post-UF calculated value of Qm minus Qa (Qm-Qa). Area under the receiver operating characteristic curves (AUC) of individual UF parameters was compared. Qm-Qa had the highest AUC (0.8295) followed by Qm (0.8241). UF performed significantly better in men ≤40 with an AUC of 0.9324 and 0.9224 for Qm-Qa and Qm respectively, as compared to 0.7484 and 0.7661 in men >40. Importantly, of men found to have anatomic recurrences, only 41% had a Qm of ≤15 mL/s at time of diagnostic cystoscopy, whereas over 83% were found to have a Qm-Qa of ≤10 mL/s. Qm rate alone may not be sensitive enough to replace cystoscopy when screening for stricture recurrence in all patients, especially in younger men where baseline flow rates are higher. Qm-Qa is a novel calculated UF measure that appears to be more sensitive than Qm when using UF to screen for recurrence, as it may be a better numerical representation of the shape of the voiding curve.