A mathematical micturition model to restore simple flow recordings in healthy and symptomatic individuals and enhance uroflow interpretation.

We describe a model and report a new method to extract quantified data from the simple analysis of whole uroflow curves in healthy and symptomatic individuals. Recorded flow curves were compared with the curves theoretically predicted from a mathematical micturition model. This model was developed by relating each physiological event occurring during micturition to a set of mathematical equations. Due to improvements in speed of computer calculations, a very fast and adaptable mathematical micturition model became available. A total of 302 uroflow curves from 142 patients (61 men and 81 women) were studied. The control group consisted of seven men and 25 women; the symptomatic groups comprised 54 men and 56 women. The mathematical model was applied to analyze all the recorded curves. For patients with lower urinary tract symptoms, specific modelization parameters were introduced according to the clinical condition to be tested. Using two compulsory (patient sex and voided volume) and two optional parameters (clinical condition and urethral catheter size), our mathematical model was able to produce uroflow calculated curves similar to observed curves. In the control group, the calculated and recorded uroflow curves were found to superimpose with an impressive accuracy, i.e., a quadratic error <1%. Test-re-test studies gave the same determination of the specific parameters. In benign prostatic hyperplasia patients, the compressive effect on both prostatic urethra and bladder neck was separately identified. The same intra-individual values were found at 2-week intervals in the group with no treatment (P = no significance), whereas after 3 months of treatment with an alpha-blocker, a decrease in values was noted in responder patients (P < 0.001). In women with various degrees of cystocele, a constrictive effect was identified and found to be identical for successive flows during the same urodynamic testing. This large prospective study demonstrated the relevance of a sophisticated, heavily computerized micturition model, taking into account physiological voiding parameters, to the study of flow in healthy individuals and patients with benign prostatic hyperplasia or cystocele. Curve-fitting led to the determination of critical events during flow such as break point and plateau phase. Determination of these events may enhance uroflow interpretation by providing additional information on the detrusor function. Neurourol. Urodynam. 19:153-176, 2000.