Challenging the maximum flow rate: A new index of voiding dysfunction in men with benign prostatic enlargement

Françoise A. Valentini, Pierre P. Nelson, Gilbert R. Besson, Philippe E. Zimmern

Research output: Contribution to journalArticlepeer-review

9 Scopus citations


OBJECTIVES: To present the theoretical development and clinical relevance of a new index of voiding dysfunction (D) based purely on free uroflow (FF), to assist in the management of patients with benign prostatic enlargement (BPE), and to compare its merits against the maximum flow rate (Qmax). PATIENTS AND METHODS: In the Valentini-Besson-Nelson (VBN) micturition model for men, two variables characterize urethral obstruction, i.e. the prostatic urethral counter-pressure pucp and the detrusor force coefficient k. D can be obtained from a FF assuming a normal detrusor (k = 1). Clinically, multiple FF from patients entered in a double-blind pharmacological trial provided variations of D over time. D values were also compared before and after transurethral resection of the prostate (TURP). RESULTS: In 137 patients with BPE from several institutions, D was more precise than Qmax because D is independent of volume and of perturbations of short duration during the flow. The change in D was proportionate to the invasiveness of treatment; the mean (sd) decrease after TURP was 14.6 (8.7) cmH2O, vs 8.1 (5.4) cmH2O after 90 days of α-blocker intake. Retrospectively, the range of D fitted with the clinician's decision, i.e. pharmacological trial (16-31 cmH2O) vs TURP (27-46 cmH2O; P < 0.001). CONCLUSION: The new index (D), deduced from the VBN analysis of only FF, is responsive to treatment. This simple calculation offers an insight into the voiding status of a patient with BPE beyond that obtained by Qmax alone.

Original languageEnglish (US)
Pages (from-to)995-999
Number of pages5
JournalBJU international
Issue number8
StatePublished - Apr 2008


  • Benign prostatic enlargement
  • Bladder outlet obstruction
  • Free uroflow
  • Voiding dysfunction index

ASJC Scopus subject areas

  • Urology


Dive into the research topics of 'Challenging the maximum flow rate: A new index of voiding dysfunction in men with benign prostatic enlargement'. Together they form a unique fingerprint.

Cite this