The role of noninvasive penile cuff test in patients with bladder outlet obstruction

PURPOSE: The aim of this study was to compare the penile cuff test (PCT) and standard pressure-flow study (PFS) in patients with bladder outlet obstruction. MATERIALS AND METHODS: A total of 58 male patients with moderate to severe lower urinary tract symptoms (LUTS) were selected. Seven patients were excluded; thus, 51 patients were finally enrolled. Each of the patients underwent a PCT and a subsequent PFS. The sensitivity (SE), specificity (SP), positive predictive value (PPV), negative predictive value (NPV), and likelihood ratio were calculated. Chi-square and Fisher exact test were used to evaluate relationships between PCT results and maximal urine flow (Qmax); a p<0.05 was considered statistically significant. RESULTS: The mean (±standard deviation) age of the study group was 65.5±10.4 years. Overall, by use of the PCT, 24 patients were diagnosed as being obstructed and 27 patients as unobstructed. At the subsequent PFS, 16 of the 24 patients diagnosed as obstructed by the PCT were confirmed to be obstructed, 4 were diagnosed as unobstructed, and the remaining 4 patients appeared equivocal. Of the 27 patients shown to be unobstructed by the PCT, 25 were confirmed to not be obstructed by PFS, with 13 equivocal and 12 unobstructed. Two patients were diagnosed as being obstructed. For detecting obstruction, the PCT showed an SE of 88.9% and an SP of 75.7%. The PPV was 66.7% and the NPV was 93%. CONCLUSIONS: The PCT is a beneficial test for evaluating patients with LUTS. In particular, this instrument has an acceptable ability to reject obstruction caused by benign prostatic hyperplasia.