The fate of the urethra after artificial urinary sphincter cuff erosion: a review of 98 patients

Introduction

The artificial urinary sphincter (AUS) is the gold standard treatment for moderate to severe male stress urinary incontinence with well documented long-term safety, efficacy, and improvement in quality of life (1,2). After AUS implantation, subsequent device infection, AUS cuff erosion, and mechanical failure can all result in recurrent incontinence and need for further surgery. Of these, erosion of the urethra is the most devastating complication and can result in negative sequelae such as urethral strictures (US), urethral diverticulum, and urinary fistulae (UF) which may require further surgery, prevent AUS reimplantation, and lead to eventual urinary diversion (2-5). As recently reflected in the American Urological Association (AUA)/Society of Urodynamics, Female Pelvic Medicine, and Urogenital Reconstruction (SUFU) Incontinence after Prostate Treatment Guideline, heterogeneity exists between specific repair techniques and catheter duration with some institutions suggesting various forms of urethrorraphy and urethroplasty (6-9).

While single center studies have examined treatment strategies after urethral erosion such as urethral catheter placement, suture urethrorraphy (abbreviated urethroplasty or in situ urethroplasty), or excision with urethroplasty (primary urethral anastamosis), there is a paucity of literature that report perioperative outcomes once the AUS is removed (7-10). Furthermore, no studies exist that specifically describe the fate of the penile prosthesis (PP) in patients who have one in situ at time of AUS erosion. As such, we present long-term outcomes of patients that have undergone AUS removal due to erosion with specific attention to rates of stricture formation and UF. We present this article in accordance with the STROBE reporting checklist (available at https://tau.amegroups.com/article/view/10.21037/tau-24-528/rc).

Methods

Under institutional review board approval, we reviewed a consecutive series of 98 patients who underwent AUS explantation for urethral erosion between July 2009 and December 2020. Patients were identified with Current Procedural Terminology (CPT) code 53446. Patients that had AUS removal for indications other than for cuff erosion were excluded. All explants were performed at University of Southern California/Norris Comprehensive Cancer Center by four fellowship-trained reconstructive surgeons (J.C.L.D., D.A.G., L.R.D., and S.D.B.). Patient demographic data, indication for AUS removal, AUS component characteristics, and post-operative outcomes were extracted and analyzed. Primary post-operative outcomes including US and UF development, infection or erosion of the PP, need for intervention for US/UF were investigated. The study was conducted in accordance with the Declaration of Helsinki (as revised in 2013). The study was approved by the Human Investigation Committee (IRB) of the University of Southern California (No. HS-12-00471) and informed consent was taken from all the patients.

Pre-operative evaluation and urinary drainage

Patient’s presenting with erosion can present with a variety of signs and symptoms but most presented with perineal and scrotal swelling, pump induration, and worsening incontinence. Though less common, we also observed erosions in which the only presenting sign was worsening incontinence. In patients with retention and/or active urine extravasation in the scrotum and perineum, cystourethroscopy is also used to facilitate safe passage of a urethral catheter (16 French) to allow for urinary drainage. In some cases, a guidewire is required to allow safe passage of the catheter into the bladder beyond the erosion point.

Operative technique

After admission and administration of broad-spectrum intravenous antibiotics, patients are taken to the operating room for device removal and debridement. If not previously placed, a 16-French urethral catheter is installed and all AUS components, including the pressure regulating balloon, are removed. A “drain and retain” technique was not used in any of the study patients. After cuff removal, abbreviated urethrorraphy is performed by reapproximating the urethral mucosa using absorbable, monofilament or braided suture. Ventral and lateral defects are often easily repaired but aggressive manipulation of the urethra if the defect is not easily visible is avoided such as in the case of dorsal defects. A similar technique is described by Siegel et al. (10). The cuff capsule and healthy, non-friable adjacent tissue is also transferred and interposed over the urethra to bolster the repair and prevent urine extravasation when feasible. Patients are then discharged home with the urethral catheter in place. Suprapubic catheters were not placed at the time of AUS removal in this cohort.

After four weeks, physical examination and cystourethroscopy are performed to confirm success of the urethral repair and the absence of UF. The urethral catheter is left in place until the urethra is healed circumferentially on cystourethroscopy and there is no evidence of UF. Patients were not maintained on oral antibiotics while a catheter was in place. Patients are deemed eligible for reimplantation only after a minimum of 4 months have elapsed after explant erosion and the patient is deemed to have a sufficiently healthy intact urethra without the presence of a clinically significant stricture based on repeat cystourethroscopy.

During cystourethroscopy, presence of a persistent defect in the urethral lumen or irrigation fluid from the perineum is indicative of persistent fistula or suboptimal epithelialization and an indication for continued urethral catheterization or surgical repair in recalcitrant cases. Similarly, retrograde urethrogram that shows extravasation of contrast would also indicate incomplete urethral healing. Comprehensive evaluation of the urethra with radiography and visual inspection is necessary in the high risk patient with persistent fluid from the perineum and prior to subsequent reimplantation.

Statistical analysis

Descriptive statistics were employed for analysis using Microsoft Excel Version 16.87 (Microsoft, Redmond, Washington). Baseline characteristics and outcomes of interest are reported as median [interquartile range (IQR)] or frequency (%) where appropriate. Data was summarized using frequency and associations were evaluated using Pearson’s Chi-squared or Fisher’s exact test as appropriate. Analyses were done in R version 4.4.2.

Results

A total of 98 patients underwent AUS removal after presenting with urethral erosion during the study time period. All patients underwent complete device removal. No intraoperative complications occurred during AUS explantation. Median age at AUS erosion was 79.4 years old (IQR, 72.7–83.1 years) with median follow-up after AUS removal of 19.8 months (IQR, 7.0–49.2 months). Median time from AUS placement to erosion was 4.2 years (IQR, 2.0–8.5 years). Study population demographics, components at time of placement, and presenting symptoms are listed in Table 1.

Presentation and hypothesized cause of erosion

Thirty-seven (37.8%) patients experienced erosion due to an identifiable iatrogenic cause such as instrumentation or catheterization. There was significant variability in how patients presented when erosion was identified within our cohort. Fifty-five (56.1%) presented with signs of infection, swelling, and urinary extravasation. Interestingly, 42.9% had erosion identified after cystoscopy was done to evaluate more subtle signs and symptoms related to the AUS device including 13.3% who presented with worsening incontinence as the only symptom.

Predisposing risk factors

While 12 (12.2%) patients had no risk factors for urethral erosion, the majority of patients (87.8%) had at least one risk factor (48%) and many had two or more (39.8%) risk factors.

Prior radiotherapy (54.1%) was the most common predisposing risk factor in the patient cohort. Forty-six (46.9%) had a history of prior urethral compromise defined as previous AUS erosion, previous urethral surgery, history of cuff relocation, dual cuff, history or urethral stent. Many patients (58.2%) in the cohort also had prior AUS surgeries/revisions for non-infectious or erosive related indications with 29 (29.6%) patients undergoing prior single component revision and 28 (28.6%) patients undergoing greater than 2 prior revisions. 28 patients had an inflatable PP in place at time of AUS erosion.

Post-operative urethral fistula

Post-removal outcomes of the study population are summarized in Table 2. Six patients (6.1%) developed a de novo urethrocutaneous fistula (UCF) with median time to fistula resolution of 3.8 months. Of these six patients, 3 (50%) had resolution of their UCF with urethral catheter drainage while 3 (50%) required fistulectomy. After resolution of UCF, four patients eventually underwent AUS reimplantation and of those one had a functional AUS at last follow-up. Outcomes from the remaining five patients include two indwelling catheter (1 urethral, 1 suprapubic) and three urinary diversion secondary to refractory UCF, de novo fistula to the pubic symphysis, and recalcitrant high-volume incontinence due to inability to reimplant an AUS.

Post-operative US

Eighteen (18.4%) patients developed a US after AUS explantation. Six had a prior history of US disease and 9 (9.2%) of the 18 patients had a de novo US after AUS erosion and explantation with 7 (7.1%) of those patients requiring urethral dilation and 2 requiring urethroplasty (2.0%). Both patients requiring urethroplasty had a concomitant US and urinary fistula. Of these 18, 12 (66.7%) were able to undergo successful AUS reimplantation with six patients having a functional AUS on last follow-up. Three (16.7%) patients underwent urinary diversion. Two patients had a concomitant US and UCF, while one patient lacked suitable urethra for reconstruction and device reimplantation. Eight (44.4%) patients manage their bladder with a urethral or suprapubic catheter. Twenty-eight patients with a PP in place at time of erosion did not develop a subsequent infection or erosion to the penile implant. For each of these patients’ a 16-French catheter was in place.

Comparative analysis

Table 3 outlines the demographics and post-operative outcomes of patients who did and did not have a US or urethral fistula after AUS erosion. Smoking history (P<0.001) and history of bulbar urethral compromise such as from prior posterior urethroplasty (P<0.001) or previous urethral pull-through (P=0.01) was significantly associated with the development of UCF and stricture.

Long-term outcomes

Finally, among all patients in the study population, 65 (66.3%) had AUS reimplantation after erosion with 47 (48.0%) patients have a functioning device, 28 (28.6%) have a urethral or suprapubic catheter, 10 (10.2%) patients have no AUS or catheter, and 14 (14.3%) underwent urinary diversion.

Discussion

By adhering to a treatment pathway that mirrors the AUA Guidelines on Incontinence after Prostate Treatment, low rates of US and UCF are achievable in patients who present with AUS erosion. While overall rates of urethral sequelae are low, based on the results of our study as well as prior studies, UCF and recalcitrant strictures that form after AUS erosion are difficult to manage and can preclude successful AUS reimplantation (5,11,12). As such, the goal of the surgeon removing the AUS should be to minimize the risk of developing these complications and in particular, UCF.

In our study, development of a UCF portends a poor prognosis for future continence and device survival. While little is published regarding urinary fistula rate after AUS cuff erosion, our rate (6.1%) is consistent with others previously reported (~2%) (5). Despite our low rates, patients with UCF pose a reconstructive challenge with half of our patients requiring open surgical exploration, debridement, and urethroplasty and half ultimately required urinary diversion. While two-thirds of patients with UCF underwent successful reimplantation only 1 (16.7%) patient within this cohort had a functional device at follow-up. It is important to mention that patients with UCF tended to have had more urethral risk factors and in particular prior urethral transection either through posterior urethroplasty or prior AUS erosion than those within the cohort that did not. This is not surprising given that their urethra was more compromised at baseline. In light of these poorer outcomes other maneuvers beyond urethrorraphy should be considered including interposition of healthy tissue over the defect and prolonged urethral catheterization beyond 4–6 weeks in patients deemed to be at higher risk for UCF. In some patients, due to combination of numerous prior insults and other factors such as age and smoking history, UCF are unavoidable and urinary diversion should be considered earlier in this patient population.

While more common than UCF, stricture formation is less predictive of subsequent AUS erosion, failure, or the ultimate need for diversion. Our protocol led to a US rate that is in-line with previously reported rates of 8–40%. For US after AUS erosion, several groups have attempted urethral repair during AUS explant and measured lower urinary tract sequelae (5,11,12). Chertack et al. compared urethral catheter placement with urethorraphy (“abbreviated urethroplasty”) and anastomotic urethroplasty (“primary urethral anastomosis”). This group found a 12% stricture rate but no differences in probability of AUS reimplantation between the two techniques in follow-up (7). Another single surgeon center found a 23% stricture rate with 35% requiring urinary diversion after 40 AUS erosions (5). Finally, a recent multicenter study with 78 patients found a 32% US rate when utilizing single-layer capsule-to-capsule urethorraphy (11). Similar to these previous studies using a form of urethrorraphy or urethroplasty at time of erosion, we found a relatively lower rate of US formation rate of 16.3% total stricture rate and 9.1% de novo stricture rate. We hypothesize that decreased extravasation of urine with urethral catheterization and removal only after confirmed resolution of urine leak minimizes scarring and subsequent stricture formation. Of the strictures that developed, most were successfully managed without need for urethroplasty. Of the 18 with de novo strictures, only two required urethroplasty. Similar to patients with UF, patients with US had a similar rate of successful AUS reimplantation. As in the case of UCF, long term follow-up again shows less than favorable outcomes with only 33% of those patients with US having a viable AUS at follow-up further emphasizing the goal of prevention of US formation.

Our study also shows the relationship between cumulative risk factors (age greater than 80, pelvic radiotherapy, previous urethroplasty, previous AUS erosion, or previous urethral stent (Urolume^TM device) and lower urinary tract sequelae. Each factor has an additive effect on compromise of the bulbar urethra, leading to an extremely “fragile urethra” as described by previous studies (13-15). Whether through microvascular compromise through radiation or macrovascular compromise via previous urethral surgery, compromise to the urethra may require surgeons and patients to abandon the lower urinary tract and consider urinary diversion at an earlier point. The results of our study given further credence to this anecdotal observation among reconstructive urologists and diversion should be considered for the patient with a persistent UCF or significant US, given the suboptimal long-term rates of AUS survival of 16.7% and 33.3%, respectively, compared to 52.6% in patients without UCF or US.

Lastly, while some have suggested that a penile prosthesis may be a risk factor for AUS erosion, our study demonstrates that when a penile implant is in place at the time of AUS erosion, crossover erosion or infection did not occur despite prolonged catheterization or extravasation of urine into the perineum or scrotum (16). We hypothesize that this is likely due to the formation of a capsule around penile prosthetic devices that shields it from external contamination. It also suggests that the glans is resilient despite the presence of a penile implant and erosion of the penile implant is not likely. Having said that, one should be still mindful of placing a catheter no larger than 16 French. Since a 16-French catheter was used uniformly in our cohort, it is possible that sizes beyond this may lead to complications related to the PP. It should be noted that no patients underwent synchronous device placement and we realize that devices placed during the same surgical setting may not have that same resilience. Nevertheless, given the rarity of synchronous device placement in the contemporary era, the results of our study should hopefully allay fears among urologists over the fate of the penile implant in patients presenting with AUS erosion who require prolonged catheterization.

Despite a high-risk population, our experience shows that AUS reimplantation is feasible with approximately two-thirds of patients able to have an AUS reimplanted successfully. While we were not able to comment on the impact of transcorporal cuff placement in our cohort due to limitations of the data set, transcorporal cuff placement is an essential technique during reimplantation of the previously eroded AUS and was broadly utilized to prevent intraoperative urethral injury and to mobilize a more robust area of urethra. What has yet to be shown is whether transcorporal cuff placement prolongs device survival or prevents erosion as shown in a recent study by Malshy et al. that studied the impact of transcorporal cuff placement in radiated patients (17). Despite conservative component selection and meticulous technique, the risk of future AUS erosion is significant in the high risk, previously eroded patient, highlighted by the observation in our study that only 48% of patients that had an AUS reimplanted still had one at time of last follow-up.

As others have reported, and what has been our experience has also reflected, is that history of erosion is the biggest risk factor for future erosion and the best strategy is to prevent erosion during the initial AUS implant through avoidance of aggressive cuff sizing, delayed device activation in patients with risk factors, use of the lower pressure 51–60 cmH₂O pressure-regulating balloon when appropriate, delayed activation, and patient education to prevent iatrogenic damage to the urethra with catheters and instrumentation (4,5,18).

Our study is strengthened by a patient population that is contemporary and inclusive of patients with complex oncologic and reconstructive histories. Furthermore, this is the largest report of outcomes after AUS erosions to date. Limitations include its retrospective nature, attrition bias, referral bias, and inability to stratify patients by the severity of erosion (5). Despite these limitations, we believe that our protocol, which has been used for close to 30 years and mirrors that of our society’s Guidelines, can help guide urologists, especially those less experienced in AUS surgery, when confronted with AUS erosion.

Conclusions

In a contemporary and high-risk cohort of patients presenting with AUS cuff erosion, rates of UCF and US are low. Prevention of these urethral complications allows for AUS reimplantation and earlier restoration of continence in patients who are eligible for a new device.

Acknowledgments

None.

Footnote

Reporting Checklist: The authors have completed the STROBE reporting checklist. Available at https://tau.amegroups.com/article/view/10.21037/tau-24-528/rc

Data Sharing Statement: Available at https://tau.amegroups.com/article/view/10.21037/tau-24-528/dss

Peer Review File: Available at https://tau.amegroups.com/article/view/10.21037/tau-24-528/prf

Funding: None.

Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://tau.amegroups.com/article/view/10.21037/tau-24-528/coif). J.C.L.D. has received speaker and consultant honoria from Boston Scientific, Coloplast, and Irrimax. J.S.L. is currently employed at Kaiser Permanente, a non-profit organization. While Kaiser Permanente is a non-profit entity, this information is disclosed for transparency and clarity. S.D.B. has received speaker honoria from Boston Scientic. The other authors have no conflicts of interest to declare.

Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. The study was conducted in accordance with the Declaration of Helsinki (as revised in 2013). The study was approved by the Human Investigation Committee (IRB) of the University of Southern California (No. HS-12-00471) and informed consent was taken from all the patients.

Open Access Statement: This is an Open Access article distributed in accordance with the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License (CC BY-NC-ND 4.0), which permits the non-commercial replication and distribution of the article with the strict proviso that no changes or edits are made and the original work is properly cited (including links to both the formal publication through the relevant DOI and the license). See: https://creativecommons.org/licenses/by-nc-nd/4.0/.

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