In the past, it was commonly assumed that the dorsal urethra is at highest risk for artificial urinary sphincter erosion. This area is at particular risk of iatrogenic injury during the relatively difficult dissection of this dorsal aspect of the urethra.  However, the most common sites of cuff erosion are in fact ventral and lateral, and least commonly dorsal. Additionally, in patients undergoing transcorporal cuff placement, following early success, the overall rate of device survival was not increased, nor was the site of erosion different compared to those undergoing bulbar urethral AUS implantation. [1]. 

Thus it has been suggested that techniques aimed at bolstering the entire urethral circumference – such as circumferential urethral wrap with pre-processed xenograft or allograft may reduce urethral erosion.  We describe a novel in situ tunica albuginea urethral wrap procedure to protect and bolster the urethra in high risk patients that can avoid the need for expensive processed tissue.

We performed a retrospective analysis of patients undergoing an in situ tunica albuginea circumferential urethral wrap at the time of AUS re-implantation for refractory stress incontinence.  Records were reviewed for patient age, prior surgery, prior radiation, severity of incontinence prior to surgery, intraoperative and postoperative complications, and urinary continence at most recent follow-up. Continence was assessed via pad use.  All patients were evaluated with history, physical examination, and preoperative cystoscopy. All patients had a diagnosis of intrinsic sphincter deficiency, and urodynamics were not routinely performed in the setting of a positive cough test and low post void residual urine. 

Surgical procedure: Through a midline perineal incision, the periurethral tissue was dissected until the urethra was identified. We opened the bulbospongiosus muscle (if present) and dissected as proximally as possible. The ventral and lateral urethra was cleared of the bulbospongiosus muscle for a length of 3cm.  Along the laterally situated corpora cavernosa, a 2x1 cm rectangle of tunica albuginea was outlined on either side of the urethra (Figure 1). The tunica albuginea was then incised superiorly, inferiorly, and laterally, and then dissected medially to cover the lateral aspect of the bulbar urethra. This was repeated on the contralateral side. The tunica wings were then sutured together in the midline with 2-0 SAS, creating a circumferential tunica albuginea wrap (Figure 2).

After the tunica albuginea wrap was complete, we dissected posterior (dorsal) to the urethra and tunica albuginea until a 2 cm window was established.  The urethral circumference (including the tunica wrap) was measured with a flexible ruler. An appropriately sized cuff was prepared and passed through the tunica tunnel, and secured around the urethra. All patients received a new 61-70 cm pressure regulating balloon and a new scrotal pump in standard fashion.

Six patients underwent the in situ tunica albuginea circumferential urethral wrap over a 2-year period, by a single surgeon. In all cases, the patients were considered high risk for urethral erosion based on prior AUS erosion. Three of 6 patients had a history of adjuvant XRT. All patients had prior AUS implantation and explantation for urethral erosion (range 1-3 prior AUS surgeries).  One patient had a functional inflatable penile prosthesis in place at the time of surgery. Average age of the patients was 75 years (range 67-83). Average pad use prior to surgery was 6.2 pads per day (range 3-15). Implanted urethral cuff size was 4.0 cm in 1 patient, 4.5 cm in 4 patients, and 5.0 cm in 1 patient. All patients were discharged home on the day of surgery.  

Average follow-up was 12.8 months (range 4-29). Average pad use at last follow-up was 0.4 pads per day (range 0-1).  Three patients had urinary retention following surgery, and were discharged home with a 12 Fr Foley catheter. One had a successful void trial on postoperative day 2, and 2 failed their trial of voiding. Both were taught clean intermittent catheterization (12 Fr straight catheter). One resumed normal emptying in 5 days and stopped self-catheterization. The other patient went to an emergency room after deciding he did not want to self-catheterize after 3 days, and had a 16 Fr catheter placed (without informing our team), and developed a device infection at 4 weeks postoperatively.  He had his device explanted without difficulty.  The tunica albuginea wrap had broken down in the midline and the wings were separated.

The surgery is similar to the well-established trans-corporal AUS implantation. The dorsal dissection deep to the tunica albuginea likely reduces the risk of iatrogenic surgical dorsal urethral injury. However, since erosion is most common at the ventral and lateral urethra, rather than the dorsal urethra, it is not surprising that the traditional transcorporal cuff placement does not reduce long-term urethral erosion rates [1]. 

With our novel approach, the entire circumference of the urethra is protected by covering the lateral and ventral aspects of the urethra with a layer of living tissue.  Unlike a circumferential wrap with xenograft or fascia lata graft, this autograft does not require the use of expensive “bottled” material. In addition, an in situ pedicled graft has several theoretical advantages over a free graft: 1) self tissue is less likely to suffer early autolysis than is foreign tissue; 2) pedicled tissue will maintain its exact position around the urethra,  directly under the cuff, without risk of proximal or distal movement prior to definitive tissue integration; 3) reduced cost by eliminating the need for a processed allograft or xenograft.

There is a high risk of urinary retention with transcorporal cuff placement [2], as well as with xenograft and autologous rectus fascia urethral wrap [3].  Our novel procedure similarly has a high rate of retention.  Our early experience has taught us that patients will likely require postoperative urethral catheterization, which increases the risk of device infection or erosion.  In our most recent and in all further cases, we are placing a suprapubic tube at the time of surgery, to avoid the need for postoperative urethral catheterization or suprapubic cystostomy.  The suprapubic tube can be removed as soon as normal voiding is established.

This early clinical experience demonstrated the safety and short-term efficacy of the in situ tunica albuginea circumferential urethral wrap as a salvage treatment for AUS revision in men with fragile urethra secondary to prior urethral erosion with or without XRT.  By protecting the lateral and ventral aspects of the urethra, where erosion is most common, we expect longer-term follow-up to demonstrate a lower rate of urethral erosion than is typically experienced in these high risk patients.  The risk of urinary retention is high, and suprapubic tube should be considered at the time of surgery to avoid the need for postoperative urethral catheterization.  Penile prosthesis is not a contra-indication to this surgical approach.

Ortiz NM, Wolfe AR, Baumgarten AS: Artificial urinary sphincter cuff erosion heat map shows similar anatomical characteristics for transcorporal and standard approach.  J Urol 2020; 204:1027-32.
Smith PJ, Hudak SJ, Scott JF, et al: Transcorporal artificial urinary sphincter cuff placement is associated with a higher risk of postoperative urinary retention. Can J Urol 2013; 6773-7.
Gani J, Hennessey DB, Hoag N, et al: A pilot study of autologous rectus fascial wrap at the time of artificial urinary sphincter placement in patients at risk of cuff erosion. Int Urol Nephrol 2020; 52:851-857.