LAUSR

Uroflowmetry is one of the first screening tests for voiding dysfunction. In addition to the standard parameters – maximal and average flow rates – the shape of the uroflow curve itself has attracted clinical research interest, because the urinary flow curve is a direct and final result of the underlying voiding pathophysiology. However, sometimes the shape is deceiving and a subjective rating can bias the interpretation. For reliable interpretation of the uroflow shape, an objective and reproducible formula is useful. In this article by Lambert et al., the authors present a formula that can effectively differentiate between the flow pattern of normal, benign prostatic obstruction (BPO) and urethral stricture disease (USD) patients. The authors are to be commended for presenting an objective formula replicating what clinicians judge intuitively based on their experiences. However, the authors’ data present the limitations of uroflowmetry itself. Despite appropriate setting of cut-off levels, the overlap between normal flow pattern, BPO and USD is impossible to ignore. Therefore, despite scientific precision, this formula might not significantly change the present clinical practice for interpreting uroflow curves. Urinary flow is produced by expulsive force of the detrusor muscle, and is gated by bladder neck, prostate, sphincter and urethral resistance. USD patients might have a healthier detrusor than BPO patients, who might be older and have a longer history of obstruction. The difference in ΔQ could reflect either the nature of the obstruction or the difference in detrusor contraction, or both. Older patients with USD might also have concomitant BPO or underactive detrusor, which could also complicate the differentiation. The clinical utility of this formula might be limited as a “quick checker” for first screening, as uroflowmetry is utilized in everyday practice today. For making a calculation of this complicated formula in a short time during busy clinical practice, ready-touse software is required. The authors might produce a smartphone application or web-based calculator and make it available, if they expect this formula to be tested by more colleagues over the world, as we did for pediatric uroflowmetry patterning. Despite the aforementioned drawbacks, the minimal invasiveness of uroflowmetry should encourage and promote more research aimed at unraveling the clinical meaning of uroflowmetry curves. Further progress in “uroflowlogy” is awaited.