Comparison of Urodynamic Findings in Women With Anatomical Versus Functional Bladder Outlet Obstruction

Objectives: To characterize the symptoms and urodynamic findings of anatomical bladder outlet obstruction (AO) and functional bladder outlet obstruction (FO) in women and to determine if future endeavors at defining bladder outlet obstruction in women can group these entities together. Methods: Retrospective review of all videourodynamic studies was performed on women from March 2003 to July 2009. Women with diagnosis of obstruction were categorized based on the cause of obstruction into 2 groups: AO and FO. Demographic data, symptoms, and urodynamic findings were compared between the 2 groups. Results: One hundred fifty-seven women were identified of which 86 (54.8%) were classified as having AO and 71 (45.2%) were classified as having FO. There were no differences in symptoms between the 2 groups. There was no difference (P=0.5789) in the mean detrusor pressure at maximum flow rate Q(max) between AO (38.9 cm H2O) and FO (41.0 cm H2O). There was a difference in the Q(max) between AO and FO (10.6 [0-41.7] and 7.4 [0-35.7] mL/s, respectively; P=0.0044), but there was considerable overlap between the values in these 2 groups. Conclusions: Anatomical bladder outlet obstruction and FO have similar urodynamic voiding pressure findings, but Q(max) was statistically significantly lower in AO. However, there is a large overlap in the Q(max) values between the 2 groups. Therefore, future studies that attempt to characterize bladder outlet obstruction in women need not exclude either group.