Intérêt du lissage algébrique des nomogammes permettant l’évaluation de la contractilité du detrusor de la femme

Aims Nomograms based on Valentini-Besson-Nelson (VBN) model implying only 3 measurements (filling bladder volume, maximum flow-rate [Q_max] and detrusor pressure at Q_max) were recently developed to evaluate detrusor contractility (k) and urethral obstruction (U) in women. As their algebraic fitting leads to fast evaluations (Excel^® software), our aims were applications to populations of non-neurologic women without and with bladder outlet obstruction (BOO). Methods The software was applied to measurements obtained during pressure flow studies. Hidden hypothesis of nomograms were no significant contribution of abdominal pressure between onset of flow and Q_max and standard nervous excitations until Q_max. Studied populations were 202 women without symptom suggestive of obstruction and 125 women with proven anatomical urethral obstruction who underwent urodynamic study. Results For non-obstructed women, a good agreement was found between the values of k and U obtained using nomograms or a complete VBN analysis of the recorded curves. Whatever the obstructive status, there was a good correlation between the value of k and U. Evolution with ageing was similar with higher values of k and U in the BOO group. Curves k(age) and U(age) gave coefficients allowing an age adjustment. The high k value in the detrusor overactive (DO) group was consistent with a similar effect to that of BOO on the detrusor. Conclusion Evaluation of detrusor contractility (k) and urethral obstruction (U) can be obtained from the point of Q_max during pressure-flow study. Evolution with ageing is similar with (higher values) or without BOO. DO also induces an increased detrusor contractility. Level of evidence 4.