Maximum isometric detrusor pressure to measure bladder strength in men with postprostatectomy incontinence

To describe the use of isovolumetric detrusor pressure (Piso) in men with postprostatectomy incontinence and compare the rates of detrusor underactivity using Piso versus other common measurements/surrogates of bladder strength.

We evaluated 62 men referred to our institution during a 3-year period for workup of postprostatectomy incontinence. During videourodynamic evaluation, the maximum Piso was measured using a mechanical stop test--with the examiner gently occluding the penile urethra during volitional voiding. Statistical analysis was performed to evaluate the effect of patient variables on Piso.

The mean Piso was 54.6 ± 25.4 cm H(2)O. The Piso was <50 cm H(2)O in 40%. Isometric strength did not significantly correlate with age, interval since radical prostatectomy, abdominal leak point pressure, maximal urethral closure pressure, or pad use. The bladder contractility index and other approximations of detrusor underactivity were not predictive of low isometric pressure.

Detrusor underactivity is relatively common in men with postprostatectomy incontinence, with 40% demonstrating a Piso <50 cm H(2)O. Our data do suggest, however, that the use of common bladder contractility nomograms, such as the bladder contractility index, might not be appropriate in this population.