Correlation between penile cuff test and pressure-flow study in patients candidates for trans-urethral resection of prostate

Abstract

BackgroundAim of this study was to make a comparison between penile cuff test (PCT) and standard pressure-flow study (PFS) in the preoperative evaluation of patients candidates for trans-urethral resection of prostate (TURP) for benign prostatic obstruction (BPO).MethodsWe enrolled male patients with lower urinary tract symptoms candidates for TURP. Each of them underwent a PCT and a subsequent PFS. A statistical analysis was performed: sensitivity (SE), specificity (SP), positive predictive value (PPV), negative predictive value (NPV), likelihood ratio and ratio of corrected classified were calculated. Fisher exact test was used to evaluate relationships between PCT and maximal urine flow (Qmax): a p-value < 0.05 was considered statistically significant.ResultsWe enrolled 48 consecutive patients. Overall, at PCT 31 patients were diagnosed as obstructed and 17 patients as unobstructed. At the subsequent PFS, 21 out of 31 patients diagnosed as obstructed at PCT were confirmed to be obstructed; one was diagnosed as unobstructed; the remaining 9 patients appeared as equivocal. Concerning the 17 patients unobstructed at PCT, all of them were confirmed not to be obstructed at PFS, with 10 equivocal and 7 unobstructed. The rate of correctly classified patients at PCT was 79% (95%-CI 65%-90%). About detecting obstructed patients, PCT showed a SE of 100% and a SP of 63%. The PPV was 68%, while the NPV was 100%.ConclusionsPCT can be an efficient tool in evaluating patients candidates for TURP. In particular, it showed good reliability in ruling out BPO because of its high NPV, with a high rate of correctly classified patients overall. Further studies on a huger number of patients are needed, including post-operative follow-up as well.

Diagnosing bladder outlet obstruction using the penile cuff test in men with lower urinary tract symptoms

“…Although the NPV was very high, the PPV was unfortunately not. Similarly, prior studies have found high NPV values (∼88‐100%), but variable PPV values (66.7‐82%) …”

“…There are limited data regarding the relationship between PCT and PFS results . In addition, the role of PCT in clinical practice has not yet been established.…”

“…There are limited data regarding the relationship between PCT and PFS results. [8][9][10][11] In addition, the role of PCT in clinical practice has not yet been established. Griffiths et al performed the first study using the modified nomogram for PCT.…”

“…Similarly, prior studies have found high NPV values (∼88-100%), but variable PPV values (66.7-82%). 9,10,12 It is normal for the PPV and the NPV to be significantly influenced by the prevalence of the disease. In our study, the reason that the NPV is confirmed to be high can be considered to be caused by the fact that there were a small number of patients that were diagnosed with obstruction based on PFS compared to that of other studies.…”

Systematic Review of the Performance of Noninvasive Tests in Diagnosing Bladder Outlet Obstruction in Men with Lower Urinary Tract Symptoms

“…Overall, the diagnostic accuracy was high, with median sensitivity of 88% and specificity of 70%. There was low RoB across most studies, but significant heterogeneity in the threshold values used to diagnose BOO, with three studies using the nomogram developed by Griffiths et al [11,18,22], two using different nomograms [32,42], and two using a penile urethral compression-release index of either [7] 102 NRE Uroflowmetry 10 ml/s NR LPURR >2 or >3 LPURR>2 + URA >29 Q max <15 and P det Q max >50 [47] 87 NRE NIRS NIRS algorithm Yes BOOI >40 Uroflowmetry + PVR 10 ml/s and 100 ml BOOI = bladder outflow obstruction index; BOON = BOO number; BSA = body surface area; BWT = bladder wall thickness; CART = classification and regression tree; DWT = detrusor wall thickness; DAMPF = detrusor-adjusted mean PURR factor; ICS = International Continence Society; LPURR = linear passive urethral resistance relation; MLL = middle lobe length; NRE = nonrandomised experimental; NIRS = near-infrared spectroscopy; NR = not reported; NPV = negative predictive value; PCR = penile compression ratio; PCT = penile cuff test; P det Q max = detrusor pressure at Q max ; P ext max = maximum external pressure; PPV = positive predictive value; Pts = patients; Q max = maximum flow; RI = resistive index; RS = retrospective; UEBW = ultrasound-estimated bladder weight; URA = urethral resistance algorithm; VPG = voiding profilometry gradient across the bladder neck and prostatic urethra in the absence of distal obstruction; VR = velocity ratio.…”