A new index of voiding dysfunction in men with benign prostatic hyperplasia undergoing transurethral resection of the prostate adds superior information to the traditional maximum flow rate (Q_max)

Introduction: To compare Q_max and a new index of voiding dysfunction (D) obtained from free flow (FF) and intubated flow (IF) in men before and after trans-urethral resection of prostate (TURP). Material and Methods: Preoperative FF and IF of benign prostatic hyperplasia patients with bladder outlet obstruction were studied for Q_max and D, and compared to a series of post-TURP FF in the same patients obtained at interval follow-ups. Analysis was done in a blinded fashion. D was computed with the VBN® software. Results: From 24 fully studied patients, preoperative D values were similar (p = 0.61) for FF (25.6 ± 7.4) and IF (26.8 ± 7.1). Postoperatively, D values (9.6 ± 8.6) dropped (p = 0.001) and were more stable than Q_max. Range dispersion between D and Q_max for two successive FF postoperatively in a same patient was 4 times larger for Q_max over D. Conclusion: D values from FF or IF were similar preoperatively but markedly reduced after TURP. This more stable index compared to Q_max may offer an alternative approach to gauge the voiding performance of a symptomatic patient with benign prostatic hyperplasia and bladder outlet obstruction.