The significance and factors related to bladder outlet obstruction in pelvic floor dysfunction in preoperative urodynamic studies: A retrospective cohort study

OBJECTIVE To demonstrate the significance of bladder outlet obstruction (BOO) in preoperative urodynamic studies (UDS) in women who have been diagnosed with pelvic floor dysfunction including pelvic organ prolapsed (POP) and stress urinary incontinence (SUI). METHODS The medical records of 150 patients with pelvic floor dysfunction who underwent preoperative UDS at Yonsei University Health System from 2006 to 2012 were reviewed. Under the criteria of BOO, as a maximal flow rate in free-flow study (Qmax) less than 12 mL/sec and a detrusor pressure at Qmax in pressure-flow study (PdetQmax) higher than 20 cmH2O in UDS, they were divided into two groups: a group of 50 patients with BOO and a group of 100 patients without BOO. Comparisons were made between the patients with and without BOO in preoperative UDS. RESULTS In the POP-with-SUI group, 25 patients with BOO had lower mean Qmax (10.0 vs. 25.4 mL/sec, P < 0.001), higher PdetQmax (49.6 vs. 21.5 cmH2O, P < 0.001), lower maximum cystometric capacity (422.7 vs. 454.0 mL, P = 0.007), and higher postvoidal residual volume (44.3 vs. 21.1 mL, P = 0.021) than the patients without BOO. In the SUI-only group, the mean Qmax was significantly lower in the 25 patients with BOO (9.4 vs. 25.4 mL/sec, P < 0.001). The mean PdetQmax was significantly higher with BOO (39.6 vs. 25.4 cmH2O, P = 0.004). In the univariate analyses, menopause, maximum cystometric capacity, and cystoscopic bladder trabeculation were associated with BOO. CONCLUSION In the univariate analysis, menopause, MCC and cystoscopic bladder trabeculation were associated with BOO. In the multivariate model, however, no significant association with BOO was found.