Study evaluates acute urinary retention after sling surgery for management of post-RP SUI

Acute urinary retention is not uncommon among men who undergo placement of a proprietary transobturator sling (AdVance) for management of postprostatectomy stress urinary incontinence. Still, it is rarely persistent, and it is not predicted by findings from preoperative urodynamic studies, according to the results of a recently published retrospective study.¹

“Urodynamic studies are often performed prior to surgical intervention for postprostatectomy stress urinary incontinence, but their ability to predict urinary retention following male sling placement is unknown,” said Eric S. Rovner, MD, study investigator and professor of urology, Medical University of South Carolina, in Charleston.

“The results of our study, which to our knowledge is the largest to date to assess postoperative urinary retention following AdVance Sling placement, suggest that if urodynamic studies are being done preoperatively ONLY with the aim of predicting retention, then this investigation is probably not needed. Nevertheless, urodynamics studies still have a role if their purpose is to assess other issues, such as filling abnormalities,” he told Urology Times®.

The study included 391 patients who underwent placement of the AdVance Sling during the years 2007 to 2019. Approximately three-fourths of the patients (n=303, 77.5%) had preoperative urodynamics performed. Median follow-up for the entire cohort was 18.1 months.

Acute urinary retention, defined as an inability to urinate or elevated postvoid residual (PVR) after the first removal of the urethral catheter resulting in an invasive intervention, occurred in 55 (14.1%) men. The majority of those patients were recatheterized (87%), and the rest were treated with clean intermittent catheterization.

Three-fourths of the patients with acute urinary retention had resolution of the problem by their second postoperative visit. Among the 13 patients whose urinary retention persisted, 6 patients, representing 1.5% of the total cohort, had chronic urinary retention at their last follow-up visit. All 6 men were being treated with clean intermittent catheterization.

Comparisons of the preoperative characteristics in the groups with and without acute urinary retention showed no statistically significant differences in their demographics, comorbidities, previous interventions, radical prostatectomy approach, or incontinence severity. Within the subgroup that had urodynamics studies, there were no significant differences between men with and without acute urinary retention in average maximum flow rate (Qmax), detrusor pressure at Qmax (PdetQmax), PVR, bladder contractility index (calculated using the formula PdetQmax + 5 x Qmax), or presence of impaired contractility (defined as BCI <100).

Mean time to initial catheter removal was significantly shorter in men who developed acute urinary retention than in those who did not (2.8 vs 4.6 days; P = .002). In a univariate regression analysis, earlier postoperative catheter removal was the only explored factor that independently predicted postoperative acute urinary retention. The risk was 17% lower in men whose urinary catheter was kept in longer than 2 days after the sling procedure compared with the group that had an earlier void trial (P = .003).

“Neither impaired bladder contractility nor abnormal voiding detrusor activity (absence of detrusor contraction during pressure flow, presence of Valsalva voiding or low detrusor pressure at maximum flow) were predictive of acute urinary retention following sling placement,” Rovner said.

Rovner noted that the study has several strengths. These include its multicenter design, a large patient population with a significant proportion of men who had preoperative urodynamics studies, and significant follow-up time.

But the study also has limitations, some of which are inherent to both its retrospective and multicenter design. Additionally, the version of the male sling that was the focus of the study is no longer commercially available.

“Preliminary work suggests that the urinary retention rate following placement of the currently marketed AdVance XP Male Sling System may be slightly higher than the version used in our study. The difference is speculative, however, because there are no direct comparisons,” Rovner said. “It would be worthwhile, therefore, to conduct a prospective study of retention following placement of the newer version of the sling.”

Reference

1. Zheng Y, Major N, Silverii H, et al. Urinary retention after AdVance Sling: a multi‐institutional retrospective study. Neurourol Urodyn. Published online December 21, 2020. doi:10.1002/nau.24591