Evaluation of two novel urodynamic parameters in the diagnosis of female obstructive voiding

Abstract

Introduction: The Blaivas-Groutz nomogram for female bladder outlet obstruction (fBOO) has received a lot of criticism concerning its diagnostic accuracy , especially in the zone of mild obstruction. Our purpose was to compare the diagnostic value of two novel urodynamic parameters, the PdetQmax ≥ 2 Qmax (equivocal BOOI=PdetQmax-2Qmax ≥0) and the urethral resistance factor URA ≥20. Material -Study: Females with mild BOO according to B-G nomogram were divided into three groups. Group A (BOOI <0), Group B (BOOI ≥ 0 and URA < 20) and Group C (BOOI≥ 0 +URA ≥ 20). Uroflow and pressure flow parameters were compared between those three groups of females. Females with totally dysfunctional abdominal urination , without any detrusor’s contraction or without urinary flow during P-F study, were excluded from the study. One way ANOVA ,unpaired two tailed t test and fishers exact two tailed test were used for statistical analysis . Results: Sixty three females fulfill our inclusion criteria. Those were categorized as non obstructive (Group A, n=14) as obstructive only with BOOI ≥ 0 (Group B, n=23) and as obstructive with both BOOI ≥ 0 + URA ≥ 20 (Group C, n=26). According to one way ANOVA test, statistically significant differences between those three groups were found for: f-PVR(Post Void Residual during uroflow, p=0.005), f-BVE (Bladder Voiding Efficiency during uroflow, p=0.001), Qmax (maximum flow during pressure flow study, p<0.0001) Pdetmax (maximum detrusor pressure, p=0.01), PdetQmax (detrusor’s pressure during maximum flow, p=0.002) and of course BOOI (Bladder Outlet Obstruction Index, p<0.0001). The proposed PdetQmax ≥ 2 Qmax (= BOOI ≥ 0) agreed with the overall diagnosis of mild obstruction according to the B-G nomogram in 77.78% (n=49/63) of cases while the proposed URA ≥ 20 only in 41.27% (n=26/63) (Fishers exact test p<0.0001). As it was expected, based on the high percentage of agreement, none uroflow parameter where found to be statistically significant different between mild obstructive females according to B-G nomogram (n=63) and the obstructive females according to PdetQmax ≥ 2Qmax (n=49). On the contrary, f-BVE was found to be statistically significant different between the B-G mild obstructive (n=63) and the URA ≥ 20 (n=26) obstructive females (67.58 % vs 52.54%,unpaired two tailed t test=0.017). PdetQmax (29.87 vs 36.69,unpaired two tailed t test p=0.0085) and Qmax during P-F study (10.57 vs 6.69, p=0.0015) were found to be statistically significant different during the direct comparison between Groups B and C, respectively. Finally, we found that from the total 37 females with incomplete bladder emptying during uroflow (f-BVE<80%), 62.2%,21.6% and 16.2% were already categorized in groups C,B and A, respectively. Conclusion: According to our results, we recommend the use of URA cut off value 20 instead of PdetQmax ≥ 2Qmax as a second more strict urodynamic parameter especially in the grey (mild) zone of female BOO. Σκοπός της παρούσας αναδρομικής μeλέτης ήταν η αξιολόγηση δύο προτeινόμeνων ουροδυναμικών παραμέτρων στην διάγνωση της γκρίζας ζώνης της αποφρακτικής ούρησης στις γυναίκeς, της ήπιας αποφρακτικής ούρησης κατά το νομόγραμμα των Blaivas - Groutz (B - G) . Οι τιμές των παράμeτρων BOOI ≥ 0 και URA ≥ 20 ως διαγνωστικά κριτήρια υποκυστικής απόφραξης αξιολογήθηκαν μeταξύ τους, μe ουροδυναμικά κριτήρια. Σύμφωνα μe τα αποτeλέσματα της αναδρομικής μeλέτης, η προσθήκη της παραμέτρου URA ≥ 20 φαίνeται να διeυκολύνeι πeρισσότeρο τον λeιτουργικό ουρολόγο, στην ουροδυναμική διάγνωση της υποκυστικής απόφραξης, eιδικά στις αμφίβολeς πeριπτώσeις της ήπιας απόφραξης κατά το νομόγραμμα B - G , πeρισσότeρο από ότι η προσθήκη της παραμέτρου BOOI ≥ 0.