The benefits of bladder outlet procedures in men with detrusor underactivity (DU) or acontractile detrusor (AD) remain debatable. These can produce uncertain results in men with DU, but without bladder outlet obstruction (BOO), potentially causing needless exposure to perioperative risk and long-term adverse effects(1). By contrast, bladder outlet procedures are the cornerstone of management for BOO. Two recent systematic reviews of the preoperative effect of DU on transurethral surgery for benign prostatic hypertrophy have failed to offer clarity (2,3). One concluded that preoperative DU can exclude patients unsuitable for bladder outlet procedures, finding that men with DU had less improvement on the International Prostate Symptom Score (IPSS) and maximum urinary flow rate (Qmax) compared to men without DU(2). However, they found no differences for either quality of life (QoL) or postvoid residual (PVR). The other concluded that surgical bladder outlet procedures for lower urinary tract symptoms (LUTS) in men with DU improved QoL, IPSS, and PVR(3). Urodynamics (UDS) to assess bladder contractility after bladder outlet procedures could explain both these putative clinical benefits and the underlying mechanisms. We hypothesized that surgical treatment of the bladder outlet (i.e., the prostate) can restore balance between bladder contractility and outlet resistance in favor of the bladder, thereby improving urodynamic parameters and symptoms. This systematic review describes the literature on urodynamic outcomes, symptom scores, and QoL before and after bladder outlet procedures in males with DU or AD.

We adhered to the standard PRISMA guidelines and registered the review with PROSPERO (registration no. CRD42020215832). Our search query was developed under the guidance of an information specialist and the research team, with searches on PubMed/MEDLINE, Embase, Web of Science, and Ovid Medline conducted on October 23, 2020, and updated on December 27, 2021. We included studies of men aged 18 years or older with non-neurogenic DU or AD if they had undergone a bladder outlet procedure, but we excluded studies of prostate cancer or neurogenic bladder (i.e., spinal cord injury, multiple sclerosis, or central nervous system disease). DU was defined as a bladder contractility index (BCI; PdetQmax+ 5Qmax) < 100 or a PdetQmax <40 cmH20. The primary outcomes were detrusor pressure at maximum flow (PdetQmax) and maximum flow rate (Qmax). Secondary outcomes were the IPSS and QoL. Two reviewers independently assessed the risk of bias using the National Institute of Health/National Heart, Lung, and Blood Institute (NIH/NHLBI) quality assessment tool for pre-post studies with no control group. Two reviewers assessed the certainty of evidence using the GRADE approach for each outcome.

Of the 3677 publications found, 13 pre-post studies were eventually included. Six studies showed a decrease and seven studies showed an increase in PdetQmax postoperatively (pooled mean change of 5.99; 95%CI [0.59–11.40]; P = 0.03; I2, 95%). All subgroups with a preoperative BCI of <50 showed a PdetQmax increase after surgery (pooled mean difference, 20.05; 95%CI, 11.75–28.35; Z = 4.73; P < 0.00001). All studies with a preoperative BCI ≥50 showed a PdetQmax decrease after treatment (-6.99; 95%CI -13.13 - -0.86; Z = 2.23, P = 0.03), except for one using the subgroup “mild DUA”. Substantial heterogeneity existed in both analyses. An improvement in Qmax was seen postoperatively in all studies (pooled mean change of 5.87, 95%CI [4.25–7.49]; I2 93%). Quality of life was reported in three studies with a pooled significant improvement postoperatively (-2.41 points; 95%CI [-2.81 to -2.01]; P = 0.007). IPSS was described in seven studies with all studies showing an improvement (-12.82; 95%CI [-14.76--10.88]; P < 0.001). Twelve studies had a moderate risk of bias, and one had a high risk of bias (Table 3). The certainty of evidence was low for the outcomes Qmax, IPSS, and QoL, and it was very low for PdetQmax (Table 4).

All studies reported improvements in the maximum flow rate (Qmax), IPSS, and QoL, independent of the degree of bladder contractility. Furthermore, detrusor pressure at maximum flow (PdetQmax) increased after surgery for those with a BCI <50 and, but it decreased for patients with a BCI ≥50. It is widely accepted that detrusor contractile strength is determined by bladder outlet resistance. In patients treated for BOO, the PdetQmax typically decreases and the Qmax increases, whereas we found that the PdetQmax and Qmax both increased after bladder outlet procedures in patients with severe underactive bladders or AD (i.e., BCI <50 and/or PVR ≥200 mL), which is surprising.

This review shows that detrusor pressure at maximum voiding (PdetQmax) increases after surgical bladder outlet procedures in men with underactive bladders or AD (i.e., baseline BCI <50). Therefore, we derive that surgical bladder outlet procedures should not be excluded for men with DU or AD based on current evidence, and instead, should be discussed as part of the shared decision-making process. The low to very low certainty of the evidence in this systematic review and meta-analysis points to the need for further studies in this field.

Drake MJ. Is Urodynamics Necessary when Assessing a Patient with Male Lower Urinary Tract Symptoms? Eur Urol Focus. 2018;4(1):54-56. doi:10.1016/j.euf.2018.04.008
Kim M, Jeong CW, Oh SJ. Effect of Preoperative Urodynamic Detrusor Underactivity on Transurethral Surgery for Benign Prostatic Hyperplasia: A Systematic Review and Meta-Analysis. J Urol. 2018;199(1):237-244. doi:10.1016/j.juro.2017.07.079
Creta M, Ruvolo CC, Longo N, et al. Detrusor overactivity and underactivity: implication for lower urinary tract symptoms related to benign prostate hyperplasia diagnosis and treatment. Minerva urology and nephrology. 2021;73(1):59-71. doi:10.23736/S2724-6051.20.03678-4

Continence 7S1 (2023) 100729
DOI: 10.1016/j.cont.2023.100729