BERKELEY, CA (UroToday.com) - Most artificial urinary sphincters (AUS) are placed by low-volume surgeons, with a smaller number of urologists placing more than 20 per year. Data provided by American Medical Systems (AMS), the manufacturer of the AUS, reveals that in the U.S., 25 urologists put in 20 or more implants a year, representing a minority of the overall implants done. Accordingly, even for “high-volume” implanters, it may take many years to develop a large enough cohort of patients for meaningful comparisons of techniques, which makes multi-institutional studies such as these essential.
The main limitation to the present study is the lack of long-term follow up (median follow up of just over 2 years). However, there is certainly a need to understand which risk factors are important for short-term AUS failures – a particularly devastating problem for both patient and provider. This study confirmed that radiotherapy was a significant risk factor for AUS erosion. Interestingly, a history of previous urethroplasty was not a risk factor for erosion, though the study was likely underpowered (and perhaps too heterogeneous) to detect a difference. The most surprising finding was that placement of the 3.5 cm cuff was an independent risk factor for erosion. This was especially true in patients that we considered “high risk” (due to patient or surgical factors). Importantly, our data does not suggest that the 3.5 cm cuff itself is inherently dangerous. Rather, we believe the high rate of erosion in this “high-risk” cohort may be secondary to placement of an appropriately sized cuff in a diseased urethra (e.g., compromised from the radiation endarteritis or other devascularization) that may not have a blood supply robust enough to support the small cuff. As a result of the findings from this study, the TURNS group is collectively placing more transcorporal (TC) cuffs in our high-risk patients to ameliorate the risk, though it should be noted that the benefit of TC placement in this cohort has not been tested in a randomized controlled trial.
Written by:
William O. Brant, MD, FACS, FECSM as part of Beyond the Abstract on UroToday.com. This initiative offers a method of publishing for the professional urology community. Authors are given an opportunity to expand on the circumstances, limitations etc... of their research by referencing the published abstract.
Department of Surgery (Urology)
Center for Reconstructive Urology and Men's Health
University of Utah
Salt Lake City, UT USA
http://healthcare.utah.edu/menshealth/
Risk factors for erosion of artificial urinary sphincters: A multicenter prospective study - Abstract