Chronic bladder outlet obstruction (BOO) can disrupt bladder structure, eventually leading to detrusor underactivity (DU), which may be irreversible. DU is a common but poorly defined entity. According to Continence Society (ICS) DU is a urodynamic diagnosis defined by “low detrusor pressure or short detrusor contraction in combination with a low urine flow rate resulting in prolonged bladder emptying and/or a failure to achieve complete bladder emptying within a normal time span (a high postvoid residual may be present)”(1). Bladder contractile Index (BCI) has been used as bladder function value, with poor bladder contraction defined to be under 100. Experimental models of DU have shown that the bladder can recover after early deobstruction (2). However, the impact of prostatic deobstructive surgery on bladder voiding efficiency (BVE) and detrusor functional recovery in men with chronic urinary retention (CUR) and DU remains unpredictable (3). Ethics Committee has been approved.

We conducted an exploratory, non-randomized prospective study. A cohort of 13 men with CUR [postvoid residual volume (PVR) >100mL in two different evaluations] and DU [bladder contractility index (BCI) <100] were submitted to deobstructive surgery. Exclusion criteria included neurologic impairment, history of pelvic trauma/surgery/irradiation, and bladder or prostatic neoplasia. The evaluation included demographic, clinical (IPSS and quality of life questionnaires), BVE and urodynamic (pressure-flow study) assessment before and 1-year after surgery. Data was presented as mean ± SD.

Thirteen men with a mean age of 71 ± 5 years were included. At baseline, 8 patients had spontaneous voiding and 5 were catheterized. The mean PVR was 178 ± 152 mL and 265 ± 131, respectively, for each group. One year after surgery, BVE and BCI significantly increased (BVE: 43 ± 39 % to 76 ± 39 %, p = 0,012) (BCI: 77 ± 40 to 89 ± 52, p = 0.046). As expected,, in the preoperative non-catheterized group, there was a more relevant increase of BVE from 69 ± 23 % to 93 ± 19 % (p = 0.043), and contractility with BCI from 97 ± 32 to 111 ± 50 (p = 0.144). In the preoperative catheterized group, 3 out of 5 recovered spontaneous voiding, with a BVE increase from 0 % to 48 ± 51 %, but BCI recovery was poor (39 ± 19 to 45 ± 13).
Concerning urodynamic evaluation, 8 out of 13 patients remained underactive, while 5 (38 %) recovered to normal bladder contractility values. Likewise, baseline PdetQmax was significantly increased in those men that recovered normal detrusor function (67 ± 25 vs. 29 ± 10, p = 0.002), compared to those with DU after deobstruction.

In this study, we found that in men with chronic urinary retention and DU, BVE and BCI significantly improved after bladder outlet desobstruction, with differences being statistically significant. When preoperative micturition status (spontaneous vs. indwelling catheter) is taken into account, the results are comparable, with somewhat better outcomes in the non-catheterized group. These findings can be interpreted as a detrusor function recovery with better BVE, indicating that both types of patients may benefit from deobstructive surgery. Nevertheless, recovery may be more effective when the procedure is carried out at an earlier stage of bladder dysfunction.

In men with CUR, urodynamic DU should not prevent the decision to undergo a prostatic deobstructive surgery, in our series, patients significantly improved BVE and detrusor contractility. Moreover, those who were catheterized also had probability to recover spontaneous voiding.

D'Ancona C, Haylen B, Oelke M, Abranches-Monteiro L, Arnold E, Goldman H, et al. The International Continence Society (ICS) report on the terminology for adult male lower urinary tract and pelvic floor symptoms and dysfunction. Neurourology and urodynamics. 2019;38(2):433-77.
Vale L, Charrua A, Cavaleiro H, Ribeiro-Oliveira R, Avelino A, Antunes-Lopes T, et al. DU Is Induced by Low Levels of Urinary ATP in a Rat Model of Partial Bladder Outlet Obstruction: The Incidence of Both Events Decreases after Deobstruction. Advances in urology. 2022;2022:6292457.
Chapple CR, Osman NI. Underactive Bladder Versus Bladder Outlet Obstruction: Don't Get Tricked! Eur Urol Focus. 2022;8(2):388-90.

Continence 7S1 (2023) 100916
DOI: 10.1016/j.cont.2023.100916