An automated penile compression release maneuver as a noninvasive test for diagnosis of bladder outlet obstruction.

Purpose:
We tested the hypothesis that the previously described penile urethral compression release (PCR) maneuver provides a valid diagnosis of bladder outlet obstruction (BOO) using automated rather than manual penile compression by controlled inflation of a penile cuff. We also investigated urodynamic events underlying generation of the PCR index.

Materials and Methods:
A total of 150 subjects attending for pressure flow studies were studied using conventional and noninvasive cystometry. Patients were classified into urodynamic diagnostic groups using standard invasive studies. The PCR index was calculated for each individual from noninvasive penile cuff data and the results were summarized for each group. ROC analysis of the PCR index was performed to define an optimum threshold for BOO diagnosis. Simultaneous invasive and noninvasive data were used to define the relationship between the PCR index, bladder contractility and the maximum flow rate.

Results:
The mean PCR index ± SD was significantly higher in the BOO group compared to the normal cystometry group (215% ± 84% vs 93% ± 39, p <0.01). ROC analysis showed that a PCR index of greater than 160% diagnosed BOO with 78% sensitivity, 84% specificity and a positive predictive value of 69%. There was a strong positive correlation between the PCR index and isovolumetric detrusor pressure, which is a measure of bladder contractility (r = 0.44, p <0.01).

Conclusions:
The results of this study suggest that the PCR index combines valid estimates of bladder contractility and the maximum flow rate, and it represents a clinically useful, noninvasive urodynamic parameter for the diagnosis of BOO.