The detrusor underactivity (DUA) as defined by the International Continence Society (ICS) is “a contraction of reduced strength and/or duration, resulting in prolonged bladder emptying and/or failure to achieve complete bladder emptying within a normal time span” based on urodynamics. It is highly probable that multiple factors contribute to develop this dysfunction which is estimated to affect from 9% to 28% of males under 50 years of age and 48% of male over 70 years of age. DUA is particularly difficult to diagnose since these patients often refer both storage and voiding symptoms and because none of those are considered pathognomonic.  It is known that DUA often coexists with lower urinary tract dysfunction (LUTD) especially in older patients. Many studies describe bladder outlet obstruction (BOO) as a cause of DUA but the pathophysiology underneath this relationship remains unclear. The aim of this study is to evaluate whether the treatment of bladder outlet obstruction, in patients affected by both DUA and BOO, may lead to an improvement of urodynamic parameters and quality of life.

All patients received a diagnosis of both DUA and BOO on urodynamic findings [DUA: Qmax <12 mL/s, Pdet@Qmax <30 cmH2O, bladder contraction index (BCI= Pdet@Qmax + 5Qmax) <100; BOO: bladder outlet obstruction index (BOOI= Pdet@Qmax – 2Qmax) >40]. Further examinations, such as urethrocistoscopy and transabdominal ultrasound, were performed to have a complete diagnostic evaluation of the BOO. Excluding criteria were neurogenic lower tract dysfunction, diabetes mellitus, pelvic ischemia, and patients on anticholinergic therapy. Urodynamic test, uroflowmetry, physical examination and IPSS (International Prostate Symptom Score) were performed 1 month before surgery and then repeated at 3, 6 and 12 months of follow-up. Different types of surgery were performed: 32 patients (37%) underwent TURP, 28 patients (32%) underwent HoLEP, 19 patients (22%) underwent Aquablation and 7 patients (9%) underwent robot assisted simple prostatectomy as described by Millin.

The study was conducted on 86 male patients collected from September 2019 to September 2022. 70 patients (81%) resulted in increasing of Qmax value (1,8 mL/s on average) and 63 patients (73%) showed increase of the Pdet@Qmax (3,8 cmH2O on average) as well as the bladder contraction index (BCI), even not statistically significant. The BOOI resulted improved in all patients, even though no statistically significance was observed. A statistically significant reduction of the PVR (p <0.05) (mean 56,4 mL) was reported in 54 patients (62%). Especially, these patients referred a significant improvement in quality of life as assessed by the mean decrease of the IPSS score (9 points; p <0.05). Another interesting data was observed in 27 out of 32 subjects referring preoperative urgency (84%) that observed a complete resolution of this symptom. Moreover, 23 out of the 25 patients (92%) with indwelling catheter resumed spontaneous voiding at postop catheter removal.

The treatment of BOO in male patients affected by non-neurogenic DUA is still controversial, and not fully supported by high-level studies evidence. This investigation showed that surgical treatment may result in a significant increase in quality of life when detrusor contractility is still partially preserved. Furthermore, the study confirms surgery as the treatment of choice in patients with indwelling catheter.

This investigation showed as the surgical treatment may represent the treatment of choice in underactive bladder patients especially in subjects with indwelling catheter.

AW Thomas, A Cannon, E Bartlett, et al.: The natural history of lower urinary tract dysfunction in men: minimum 10-year urodynamic follow-up of untreated bladder outlet obstruction. BJU Int. 2005; 96:1301-1306.
M Kim, CW Jeong, SJ Oh: Effect of preoperative urodynamic detrusor underactivity on transurethral surgery for benign prostatic hyperplasia: a systematic review and meta-analysis. J Urol. 2018; 199:237-44

Continence 12S (2024) 101409
DOI: 10.1016/j.cont.2024.101409