Detrusor underactivity after radical prostatectomy: a prospective observational study

Cymbalista G1, Oszczudlowski M1, Dobruch J1

Research Type

Clinical

Abstract Category

Male Stress Urinary Incontinence (Post Prostatectomy Incontinence)

Abstract 148
Male Incontinence: What is in the Pipeline for Postprostatectomy Incontinence
Scientific Podium Short Oral Session 14
Thursday 24th October 2024
12:52 - 13:00
Hall N106
Detrusor Hypocontractility Incontinence Prospective Study Voiding Dysfunction
1. Department of Urology, Centre of Postgraduate Medical Education, Warsaw, Poland
Presenter
Links

Abstract

Hypothesis / aims of study
To evaluate the impact of radical prostatectomy on bladder function with special interest in detrusor underactivity (DU) and to appraise clinical significance of DU in post- prostatectomy patients.
Study design, materials and methods
This was prospective, observational study conducted on male patients subjected to laparoscopic radical prostatectomy (LPR). Urodynamic studies were performed at the day before surgery (visit 1), 3 to 6 months postoperatively (visit 2) and more than 12 months after surgery (visit 3). Incidence of DU that occurred after LPR (de novo DU) and  incidence of persisting de novo DU after 12 months were assessed. Diagnosis of DU was based on assessment of isovolumetric detrusor pressure (Piso) (cut‐off value of 50 cmH2O) with mechanical stop test during voiding phase. Moreover, clinical relevance of DU after LPR and predictive factors of de novo DU were appraised. 
The flow of patients between the first and second visit in terms of DU incidence was appraised using McNemar test for the assessment of de novo DU.  U Mann‐Whitney test for continuous independent variables and the chi‐square test or Fisher's exact test for independent categorical variables were utilized to access clinical relevance of DU. Univariate and multivariate logistic were used for identification of predictive factors of de novo DU. The level of significance was set to p = 0.05 for all calculations.
Results
Urodynamic findings and PROMS at each visit are presented in Table 1. Ninety nine of 100 patients underwent preoperative UDS (visit 1) and those were included in further analysis. Eighty four and 76 patients were available for follow-up at second and third visit respectively. De novo DU occurred after LPR in 25 (29.7%) patients at visit 2 (p<0.001). Sixteen from 24 patients (66,7%) who developed de novo DU after RP (visit 2) continued to have DU one year after surgery (visit 3) (p=0.04). On the multivariate analysis, urinary incontinence requiring more than 1 pad per day (OR 5.11; CI 1.69-17.19; p=0.005) and preoperative IPSS storage sub-score (OR 1.25; CI 1.03-1.63; p=0.030) were significantly associated with de novo detrusor underactivity. Post-prostatectomy patients with DU had significantly lower Urinary Assessment Urinary Assessment of the Expanded Prostate Cancer Index Composite (EPIC) total score (819 vs 911, p=0.02), EPIC Function domain score (300 vs 357, p=0.002) and EPIC Urinary incontinence domain (137 vs 224, p=0.002) when compared to their counterparts without DU (Table 2)
Interpretation of results
Our study revealed higher than expected incidence and persistence of de novo detrusor underactivity after LRP. DU after RP may be attributed to detrusor denervation related to autonomic nerve damage during surgical dissection. This applies specifically to the dissection in the proximity of the bladder neck and the removal of the seminal vesicles. There are several hypotheses proposed to explain relatively high incidence of DU in men after RP. First of all, the rate of DU appears to be strictly dependable on formula used for assessment of bladder contractility during UDS. The authors believe that optimal method to evaluate bladder contractility in men after RP is the assessment of Piso with mechanical stop test during voiding phase which was utilised in this study. In the majority of previously reported studies, however, Schafer nomogram, bladder contractility index (BCI) and other formulas based on Qmax and PdetQmax were utilized. 
Co-incidence of de novo DU and  postoperative SUI requiring more than 1 pad per day may be explained by  both autonomic and somatic denervation during bladder neck and prostate dissection.
Moreover, significant correlation between preoperative IPSS scores and incidence of de novo DU was found. This may be explained by hypothesis that patients who have a lower reserve capacity for preoperative voiding function are more likely to develop postoperative DU after RP.
Concluding message
Radical prostatectomy substantially influences bladder function, causing de novo detrusor underactivity, which persists in substantial number of patients one year postoperatively. Furthermore, significant correlation between DU and postprostatectomy urinary incontinence may plays a role when anti-incontinence surgery is considered.
Figure 1
Figure 2
Disclosures
Funding NONE Clinical Trial No Subjects Human Ethics Committee Local institutional register for prospective studies (Centre of Postgraduate Medical Education, ID: 55/PB/2017) Helsinki Yes Informed Consent Yes
Citation

Continence 12S (2024) 101490
DOI: 10.1016/j.cont.2024.101490

19/11/2024 18:03:09