Detrusor underactivity in men with lower urinary tract symptoms/benign prostatic obstruction: characterization and potential impact on indications for surgical treatment of the prostate.

PURPOSE OF REVIEW: Detrusor underactivity is a highly prevalent type of voiding dysfunction in men and responsible for residual urine and decreased voiding efficiency. Patients with detrusor underactivity have an unfavorable outcome after prostatic surgery and do not have better long-term results than untreated detrusor underactivity patients. Therefore, differentiation between detrusor underactivity and bladder outlet obstruction (BOO) is crucial for the prediction of the outcome of prostatic surgery.

RECENT FINDINGS: Patients with detrusor underactivity report more frequently about decreased/interrupted urinary flow, hesitancy, feeling of incomplete bladder emptying and/or decreased bladder sensation compared with men with normal pressure-flow studies. Determination of and differentiation between detrusor underactivity and BOO is only possible by pressure-flow studies. Threshold values for the diagnosis of detrusor underactivity have to be adjusted to the BOO-grade. A nomogram using BOO-index and maximum Watts factor is currently the most advanced tool to diagnose detrusor underactivity and/or BOO; values below the 25th percentile line indicate detrusor underactivity. It is desirable to establish tests to noninvasively diagnose detrusor underactivity. The combination of ultrasound detrusor wall thickness and bladder capacity can safely detect detrusor underactivity.

SUMMARY: Careful assessment of voiding dysfunction to discriminate between detrusor underactivity and BOO should be done with pressure-flow studies, can avoid unsuccessful prostate surgery and helps in counselling patients.