[The 4-stage continence-micturition cycle. The presentation of a urodynamic, diagnostic and therapeutic abacus]

The complexity of the mode of operation of the bladder and urinary sphincter has led to the development of a number of temporospatial physiologic models that divide the process of micturition into several stages in order to facilitate investigations. Ten years ago, the authors described a two-stage continence-micturition model intended to improve the accuracy of studies of urodynamic disorders and thus contribute to the development of more effective and more rational therapeutic solutions. A large number of diseases can affect the distal urinary tract and recent advances in neurophysiology [10] have made the selection of the appropriate therapy extremely complex. Consequently, the authors have developed a decision analysis system that simultaneously confronts diseases, urodynamic manifestations, risks for the patient, and the main therapeutic approaches available. In 1985, they increased the number of stages in their continence-micturition model from two the four. This four-stage model has provided satisfactory result when used with an abacus for modeling observed biologic phenomena. In addition to offering simulation exercises for teaching purposes, this abacus provides the means for studying the instantaneous urodynamic situation (correspondences between cycle time points, symptoms, and effects of treatments) and determining the effect of various medicosocial events on the course of the bladder and sphincter dysfunction. The authors hope this abacus will be an attractive aide to the understanding of the complex function of the distal urinary tract.