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

AIMS: To elucidate whether preoperative urodynamic findings can predict outcomes of transurethral resection of the prostate (TUR-P). METHODS: 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. RESULTS: 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. CONCLUSIONS: Preoperative evaluation of DI is of benefit because it enhances predictive value of the PFS.