Detrusor underactivity in pelvic organ prolapse

Introduction and hypothesis: The association between pelvic organ prolapse (POP) and detrusor underactivity (DU) is not well defined. The primary outcome of this study was to evaluate the prevalence of DU in a cohort of patients with POP and its association with symptoms, anatomy. and urodynamic findings. The secondary outcome was to evaluate the evolution of lower urinary tract symptoms after POP repair between DU and non-DU patients.

Methods: Consecutive patients who underwent preoperative urodynamic tests were retrospectively analyzed. Detrusor underactivity was evaluated by the Bladder Contractility Index (BCI = pDetQmax + Qmax × 5) proposed by Abrams. A BCI < 100 was considered indicative of an underactive bladder. Patients with underactive bladder were considered group A, whereas the remaining patients were classified as group B.

Results: A total of 518 patients were studied. According to BCI, detrusor underactivity was identified in 212 (40.9%) patients (group A). Group A showed higher rates of voiding symptoms (59.4% vs 36.3%, p < 0.0001) and positive (>100 ml) postvoid residual (29.7% vs 9.8%, p < 0.0001). Conversely, they displayed lower rates of urge incontinence (15.1% vs 23.2%, p = 0.02) and detrusor overactivity (15.6% vs 23.9%, p = 0.02). Preoperative Pelvic Organ Prolapse Quantification (POP-Q) demonstrated greater Aa (+1.1 ± 1.5 vs +0.9 ± 1.5, p = 0.03) and Ba (+1.4 ± 1.7 vs +1.2 ± 1.7, p = 0.04) points values in patients in group A. After POP surgery, postoperative voiding symptoms were similar in the two groups (16% vs 15.7%, p = 0.91).

Conclusions: Our study showed a 40.9% prevalence of DU in POP patients. DU was associated with the presence of voiding symptoms and positive PVR. Moreover, cystocele showed to be more severe in DU group. After surgical repair of POP, voiding symptoms of DU patients became equal to non-DU ones, suggesting that obstruction removal might recover DU in these patients.