Detrusor instability with equivocal obstruction: A predictor of unfavorable symptomatic outcomes after transurethral prostatectomy




To elucidate whether preoperative urodynamic findings can predict outcomes of transurethral resection of the prostate (TUR-P).


Sixty-two patients with symptomatic benign prostatic hyperplasia were categorized in three different ways based on findings of preoperative pressure-flow study (PFS) and cystometry: urodynamic obstruction (determined by the Abrams-Griffiths nomogram), detrusor instability (DI), and combination of both. Outcomes of TUR-P regarding symptom, function, and quality of life (QOL) were analyzed by changes in the International Prostate Symptom Score (I-PSS), maximum flow rate in uroflowmetry, and QOL index before and after TUR-P, respectively. Overall outcome was defined as success when all of the three categories showed successful improvement.


Neither urodynamic obstruction alone nor DI alone predicted outcomes of TUR-P. However, symptomatic and overall outcomes were significantly worse in patients who were not obstructed but had DI. Postoperative persistent DI was more frequently noted in patients without clear obstruction (60%) than in those with obstruction (27%). Patients with equivocal obstruction showed less satisfactory symptomatic outcomes of TUR-P when DI was accompanied. Persistent DI might be the principle cause of unfavorable outcomes.


Preoperative evaluation of DI is of benefit because it enhances predictive value of the PFS. Neurourol. Urodynam. 21:444–449, 2002. © Wiley-Liss, Inc.