Longitudinal observational cohort study about detrusor underactivity as a risk factor for bladder neck contracture after retropubic radical prostatectomy: preliminary results.

Objectives To evaluate the association between preoperative detrusor underactivity (DU) and symptomatic bladder neck contracture (BNC) in patients undergoing radical retropubic prostatectomy (RRP), in order to identify a possible new risk factor in the etiopathogenic mechanisms of BNC after RRP. Methods A total of 100 prostate cancer patients underwent RRP after preoperative complete urodynamic examination. Detrusor contractility was evaluated by bladder contractility index (BCI), power at maximum flow (WF-Qmax), and maximum velocity of detrusorial contraction (MVDC). Follow-up included uroflowmetry with bladder post-voiding volume evaluation at 3 and 6 months after surgery and repeated urodynamic examination at 12 months. Statistical evaluation was performed using the Student’s t test (P < 0.01). Results The mean patient age was 65.6 ± 5.4 years, and pathological stage ranged from T2a to T2c. A total of 40 patients (40 %) presented normal detrusor contractility, 47 (47 %) mild DU, and 13 (13 %) severe DU. Detrusor overactivity (DO) was observed in 12 patients (12 %), small cystometric capacity in 10 (10 %), low compliance in 16 (16 %), DO plus DU (mild or severe) in 6 (6 %), and DO plus small cystometric capacity together with low compliance in 5 (5 %). Normal urodynamics were observed in 38 patients (38 %). Overall BNC incidence was 12. All patients with BNC presented preoperative DU; none presented DO or low bladder compliance. DU severity and BNC occurrence were significantly correlated (P < 0.01) for all 3 urodynamic parameters (BCI, WF-Qmax, and MVDC). Conclusions We identify DU as a possible novel risk factor for BNC formation after radical prostatectomy that may contribute to its development.