Artificial urethral sphincter (AUS) is the gold standard as a treatment for severe stress urinary incontinence (SUI) after radical prostatectomy. The number of AUS implantations has been increasing in Japan since the remedy was provided by medical insurance in 2012. Even though the AUS is implanted, symptoms of SUI worsen again because of urethral atrophy, urethral erosion, mechanical failure, and so on. In addition, once the device become infected, it should be removed. It is reported that the 5-year revision free survival rate of the device is from 60 to 75 %. The aim of this study is to investigate clinical outcome by comparing primary implantation to revision.

Fifty-eight patients underwent AUS implant surgery in our institute from 2007 to 2017, 9 of whom experienced AUS failure, and 8 of whom requested revision surgery (Table 1). Medical records were retrospectively reviewed, and clinical outcomes of revision cases were evaluated by comparing primary surgeries to revision surgeries.

Sixty-nine cases of AUS (all devices were AMS 800TM) implantation were performed. Fifty-three patients (91.4%) suffered severe stress urinary incontinence after radical prostatectomy for prostatic cancer. Nine of 58 patients (the revision group) had AUS failure in a 3-year median follow-up period; the reasons were mechanical failure, urethral atrophy and urethral erosion in 5 cases, 3 cases and 1 case, respectively. There wasn’t any case of device infection. Eight patients desired revision of the device, 1 of whom hoped for 3rd implantation. The revision surgeries were done at the same time as the removal of the previous device removal when the reason was mechanical failure or urethral atrophy. The proportions of patients having diabetes mellitus (DM) or radiation therapy (RT) history in the revision group were not significantly high in comparison to the non-revision group. On the other hand, the re-implantation surgery (2 step revision surgery) was done more than 3 months after removal of the device when the patient had urethral erosion. The procedure of cuff implantation in revision surgery was transcorporal method in all cases except for one. The operation time in revision surgery was longer than that in primary surgery, whereas there was no difference in occurrence rate of adverse event, estimated blood loss and results in 24 hour pad test after surgery between the two groups (Table 2).

The reasons of device failure are categorized as mechanical issues, urethral atrophy, urethral erosion and device infection. The revision for patients with urethral erosion or device infection appeared to be challenging as opposed to that for patients with mechanical failure or urethral atrophy, because the revision surgery should be postponed until the injured urethra is cured. Transcorporal placement of AUS has been reported as a very useful technique for the patients with frail urethra such as urethral erosion or atrophyref). In the cohort of this study, the risk factors of AUS failure, which were reported as DM or RT history, were unclear (Table1). However, the surgical outcome in the revision indicated the feasibility of the surgery since it did not cause severe adverse event and brought favorable continence. The method of transcorporal implantation could contribute to good results of revision surgery.

The failure of AUS cannot be avoided at a constant rate, even if primary surgery is performed successfully. Clinical outcome of AUS revision suggests the feasibility of the surgery. The revision of AUS should be performed if the patients wish to undergo the treatment.

Laura W, et al., Transcorporal artificial urinary sphincter implantation as a salvage surgical procedure for challenging cases of male stress urinary incontinence: surgical technique and functional outcomes in a contemporary series BJU Int 2013; 112:1163-68