Urodynamics rationale. The flow curve

OBJECTIVE: To describe the mathematical representation of a common phenomenon: the urinary flow curve. METHODS: The statistical adjustment for minimum squares was the method employed in the study. RESULTS: A mathematical expression was obtained with a goodness of fit for each flow curve and an acceptable margin of error. CONCLUSIONS: The model which considers the flow curve as a parabola is not useful since this is an expression of a statistical phenomenon that varies from case to case. We utilized the minimum squares fit to obtain a regression curve that provides the nearest possible representation of urinary flow. Furthermore, we consider the flow curve to be the result of forces that develop in the detrusor, which produces the complex phenomenon of voiding. This study is the first step toward the development of a mathematical representation of the urinary flow mechanics.