Noninvasive techniques for the measurement of isovolumetric bladder pressure

A total of 184,000 prostatectomies were performed in the United States in 2000 for the relief of presumed bladder outlet obstruction. However, it has been reported that prostatectomy using current indications fails to bring about symptomatic improvement in approximately one-fourth of patients. Pressure flow studies are currently recognized as the gold standard for the diagnosis of bladder outlet obstruction. However, these studies are associated with a number of disadvantages. They are time consuming, invasive and expensive, and carry some morbidity for the patient. It has been suggested that the use of pressure flow studies should be mandatory before surgery. The invasive nature of this test limits its application, and a variety of noninvasive methods have been suggested to circumvent the need for conventional urodynamics.

We conducted a MEDLINE search of the published literature on the use of noninvasive techniques to measure bladder pressure.

Two promising techniques involve the noninvasive measurement of isovolumetric detrusor pressure. The first of these methods uses an external condom catheter and the second an inflatable cuff around the penis. Both of these methods rely on the interruption of urinary flow and the measurement of the bladder pressure transmitted along the fluid column between bladder and site of urethral occlusion. An alternative strategy analyzes flow patterns following compression and release of the urethra during voiding.

Of the methods reported the penile cuff, which is inflated during voiding, or the penile squeeze technique, which infers bladder pressure from flow patterns, would seem the most likely to be clinically useful. A noninvasive measure of bladder pressure, allied to a free flow rate, would give a useful adjunct to the assessment of men with lower urinary tract symptoms.