[Comparison of the urodynamic stop-flow test and degree of obstruction in prediction of postprostatectomy outcome].

Objective: to compare predictive value of urodynamic parameters (level of obstruction and stop-flow test) to post prostatectomy outcome.

Sample And Methodology: 30 patients elected for prostatectomy based to the patient's symptoms, radiological signs of benign prostate enlargement and signs of the retention of urine. All patients underwent complete UDM-uroflowmetry, cystometry and pressure/flow studies, after fulfilling International Prostatic Symptom Score (I-PSS). Three months after operations patients were submit same tests. Schafer nomogram was used for determination of grade of obstruction as well as grade of detrusor contractility, and stop flow test is performed to calculate maximal estimated flow (Qmaxest).

Results: 7 (23, 5%) patients were out of obstruction before the operation coupled with detrusor under activity. Postoperatively group symptoms reduction, reduction of post void residual (PVR) urine and increase of Qmax was noticed. Incidence of detrusor hyperactivity is reduced. As a measure of absolute postoperative success for the individual patient, I-PSS <7 with Qmax >15 ml/sec is taken. By this way, urodynamic measurement have shown sensitivity of 75%, specificity of 91%, PPV of 75% and post-test probability of 78% for prediction of excellent postoperative outcome for the patients with strong detrusor who were in the obstruction preoperatively, while stop-flow test with Qmaxest >35ml/sec showed lower predictive value of postoperative success (sensitivity of 89%, specificity of 62%, PPV of 50% and post-test probability of 50%).

Conclusion: Preoperatively obstructed patients with preserved detrusor contraction according to Schafer nomogram will experience much better outcome, while stop-flow test is not powerful indicator of postoperative favorable outcome.