Endoscopic buccal urethroplasty for membranous stricture disease

Introduction

Urethral stricture disease represents a longstanding challenge in urology, having significant impact on patients’ quality of life while negatively impacting renal function and urinary tract infection rates. Due to its close proximity to the prostate, the bulbomembranous urethra is subject to permanent and progressively detrimental effects of radiation, making managing radiated bulbomembranous stricture disease even more challenging in patients who have received pelvic radiation.

Surgical interventions aimed at alleviating strictures in this region must carefully balance the restoration of urethral continuity with the risk of complications. Traditionally, the initial management of these strictures has favored less invasive techniques, including urethral dilation and endoscopic urethrotomy, though long-term success rates remain poor (1). The gold standard treatment for bulbomembranous urethral stricture disease is open urethroplasty, but this surgical approach remains time intensive and technically challenging. Early endoscopic urethroplasty techniques relied on deployment of grafts into urethrotomy beds using grafts secured to catheters. The number of patients treated in each series is relatively small (range between 3 and 11), and limitations of some of these early experiences include poor definition of success and radiated patients were often excluded (2-6).

Using these historic approaches as a guide, we introduce a novel endoscopic urethroplasty using a laparoscopic suturing instrument within a transurethral sheath for buccal mucosa graft inlay urethroplasty. We aim to discuss preoperative provisions, surgical techniques and tips, postoperative considerations, and outcomes for male patients who underwent endoscopic buccal mucosal graft urethroplasty (EBMGU) for membranous stricture disease. We present this article in accordance with the SUPER reporting checklist (available at https://tau.amegroups.com/article/view/10.21037/tau-24-430/rc).

Methods

Consecutive patients treated with EBMGU between February 2022 and December 2024 at a single tertiary institution by a single surgeon for management of symptomatic membranous stricture disease were retrospectively reviewed. Diagnosis of membranous stricture was confirmed by inability to pass a 17-Fr flexible cystoscope. Patients with obliterative strictures were included, as were patients with history of radiation. Patients with stricture disease outside of the membranous urethra were excluded. Patient demographics, including age, comorbidities, stricture etiology, prior attempts at treatment, and history of prostatectomy were recorded. Preoperative evaluation included stricture characterization, peak flow, post void residual (PVR), continence status, and urine cultures. Intraoperative evaluation included graft dimensions, OR time, estimated blood loss, and perioperative complications. Additional follow-up data, including greater than 30-day complications, need for reoperation, and artificial urinary sphincter (AUS) placement. The study was conducted in accordance with the Declaration of Helsinki and its subsequent amendments. Written informed consent was obtained from the patient for publication of this article and the accompanying images. A copy of the written consent is available for review by the editorial office of this journal.

Preoperative preparations and requirements

History

During the initial evaluation, patient history is ascertained. We evaluate what form of radiotherapy was administered in addition to whether this was before or after prostatectomy. Patients will also complete an international prostate symptom score (IPSS) as well as an international index of erectile function score (IIEF). Care is taken to elucidate overactive symptoms, including nocturia, nocturnal enuresis, daytime frequency, and urgency. Prior interventions will also be noted, and whether these interventions resulted in post procedural incontinence.

Exam

Patients presenting with a history of radiation therapy will undergo a preoperative cystoscopy to evaluate the exact location of the stenosis. During the cystoscopy, patients are asked to squeeze the external sphincter, a step we call the “Kegel Wink”, to ascertain if the stenosis starts within the bulbar, membranous, or anastomosis. If the stenosis is unchanged during a wink, then it likely starts in the bulbar urethra, if the stenosis disappears then it likely is within the membranous urethra, and if the wink is seen, and the stenosis is proximal, then it is likely isolated to the anastomosis or prostate.

During cystoscopy, the bladder is filled as full as possible, and the volume is noted. Stress maneuvers are also deployed to assess incontinence. Patients will then perform a uroflow assessment with a ultrasounographic PVR assessment. If the overall capacity is low, <200 mL, we will recommend cystectomy over urethral repair.

If a preoperative suprapubic tube is in place, which is often the case, we will place the cystoscope via the tract to complete the evaluation. The appearance of the bladder is noted, including degree of radiation injury, and any necrosis or calcifications within the region of stenosis. If there is significant necrosis or calcifications, we will recommend cystectomy over urethral repair.

Imaging

Preoperative magnetic resonance imaging (MRI) is used to evaluate the bladder neck for any evidence of dehiscence, the distance between the urethra and the pubic bone, and to determine if there is any rectal tethering. The MRI can also be used to determine the presence of any fistula, osteitis pubis, or rectourethral fistulae. In addition, a pelvic computed tomography (CT) scan is used to evaluate for any calcifications. Any evidence of wide bladder neck separation, fistulae, or osteitis, we will recommend cystectomy over urethral repair. A narrow distance between the urethra and the pubic bone or rectum guides the decision to perform dorsal or ventral graft placement, respectively.

Preop recommendations

If able, we do prefer patients to initiate preoperative hyperbaric oxygen therapy. While there is no definitive evidence that this enhances outcomes, we have seen some patients with resolved necrosis with hyperbaric therapy. Pre-operative workup and considerations in patients undergoing EBMGU for membranous stricture disease are summarized in Table 1.

Step-by-step description

Our original technique for endoscopic buccal urethroplasty has been previously published (7). With experience, we have made several adjustments and refinements to improve the efficacy and efficiency of the technique. This technique requires basic endourologic skills that most urologists are equipped with, and the learning curve is estimated at approximately 10 cases for those individuals. The patient is positioned in dorsal lithotomy with the endotracheal tube positioned off to the side contralateral to the planned graft harvest site. For non-obliterative strictures, a 30-Fr NephroMax™ balloon (Boston Scientific, Marlborough, MA, USA) dilation is performed through the stricture. If not already in place, a 20-Fr suprapubic sheath is placed after the urethral dilation. For obliterative strictures, a flexible cystoscope is introduced through the suprapubic tract and a rigid cystoscope is advanced into the urethra to the level of the stricture. A 5-Fr rigid endoscopic needle (REF MRN-518, Laborie, Minnetonka, MN, USA) is passed through the stricture under direct visualization, and a wire is advanced into the bladder in a retrograde fashion (Figure 1A). The stricture is then dilated using the same balloon (Figure 1B). Next, using a standard bipolar plasma loop™ (Olympus Medical, Boston, MA, USA), either the ventral or dorsal urethral plate is minimally resected to create a smooth bed within the membranous urethra. We determine the location of graft placement based on the appearance of the urethra after dilation and preoperative imaging, favoring the side with more distance to the surrounding structures for the graft.

Figure 1 Management of obliterative membranous urethral stricture. (A) Needle and wire are passed retrograde under direct visualization with a cystoscope placed antegrade. (B) Balloon dilation of the stricture over wire. (C) Placement of antegrade stay suture at the bladder neck using the RD180. (D) Following graft deployment, quilting of the graft to the bed using SecureStrap.

Buccal mucosal graft is harvested in a standard fashion with graft width typically being 1.5 cm. The JNW Urtrac sheath (LSI Solutions, Victor, NY, USA) and a digital flexible ureteroscope within the sheath are advanced to the level of the proximal aspect of the membranous urethra. Using graspers, the tail end of a 2-0 Monoglyde suture is brought into the bladder and extracted through the suprapubic tract (Figure 1C). Using the RD180 laparoscopic suturing device (LSI Solutions), a robust bite is taken on the right side, either anterolateral or posterolateral depending on the orientation of the future graft. The other end of the suture is brought out through the urethral meatus. The same is repeated on the left side using a second 2-0 Monoglyde suture, and care is taken to preserve the left-right laterality of these sutures. The two sutures exiting out the meatus are secured to the proximal end of the graft using a free-eyed needle (Aspen Surgical, Coon Rapids, MN, USA). Long stay sutures are placed at the distal aspect of the graft to prevent twisting and to keep the correct left-right orientation during graft deployment.

For graft deployment, the suture ends emerging through the suprapubic tract are tensioned, parachuting the graft through the urethral meatus into the graft bed. Once proper graft orientation is verified using the Urtrac sheath, a 5-mm SecureStrap (Ethicon, Cincinnati, OH, USA) is used to secure the graft to previously created urethrotomy. Only a few tacks are placed. Completed graft deployment is shown in Figure 1D, demonstrating dorsal grafting in this example. A wire is advanced into the bladder, ensuring it travels within the lumen and along the inner mucosal surface of the secured graft. A 22-Fr council tip catheter is advanced over a wire into the bladder. The Monoglyde sutures are trimmed at the level of the skin, and the Vicryl sutures are trimmed at the distal urethral meatus, and a 16-Fr suprapubic tube is placed through the suprapubic tract at the conclusion of the case.

Postoperative considerations and tasks

Post-operatively, patients typically are dismissed the same day as their procedure. We perform catheter removal at 1 month following surgery and cap the suprapubic tube. If patients are able to void, or are incontinent without retention, they return for cystoscopy at 2 months. If the urethra is patent, then the suprapubic tube is removed. During the one-month voiding trial, if there is early issues with voiding, the patients are taken to the operating room for dilation before the tract can occlude. We have had several patients who had adhesions of the graft, that resolved with a one time dilation. Ideally, the patient will remain on postoperative hyperbaric oxygen (HBO) for at least one month if they have history of radiation. Follow-up cystoscopy, IPSS, and IIEF, are obtained at 4 and 12 months to assess for symptom recurrence. If the patients are recovering without retention, we anticipate AUS 4 months post operatively.

Tips and pearls

Learning curve

When taking on this new procedure, it is advised to have a backup plan. As we started on this path to full endoscopic surgery, we were first performing open dorsal onlay urethroplasty as previously described (8). We would perform the surgery endoscopically, but when there was difficulty with deployment, we would open and ensure we had good orientation. In addition, we were using laparoscopic instruments to aid in the open portion of the procedure (9). As the steps became more reproducible, we were able to transition to an entirely endoscopic approach. If someone is more adept at robotic surgery, it may be more beneficial to use a hybrid robot approach from above to aid in graft deployment.

Suprapubic tube position

Proper suprapubic tube position is key. We prefer a preoperative CT scan or MRI to delineate the relationship between the intestine and bladder. If able, we aim to place the suprapubic tube three finger breadths above the symphysis to allow a straight line to the bladder neck. If the patient had a poorly placed suprapubic tube prior to surgery, we would reposition this intraoperatively to ensure we have the easiest access possible.

Imaging

Using preoperative MRI is incredibly helpful. Measuring the distance between the urethra and the rectum and the urethra to pubic bone helps determine if we will do a dorsal or ventral graft. Also, it can help us determine if there is a clear separation between the bladder neck and urethra that would warrant an alternative operation.

Counseling

Often the patients who choose radiation do so to avoid surgery. It is important to emphasize to patients that the goal is a patent urethra, and if they are leaking continuously postoperatively, that was the goal and a mark of a successful outcome. Not everyone will have postoperative incontinence, but in radiation, and prior prostatectomy, it is the norm.

Results and early outcomes

A total of 28 men with membranous stricture disease are included in this study. Twenty-four (85%) had prior radiation, and 4 had a history of pelvic fracture urethral injury (PFUI). Twenty (71%) had undergone prostatectomy, 5 (17%) patients had an obliterative stricture disease, 26 (93%) patients had at least one prior intervention, and no patients had prior urethroplasty. Median age was 71 years (range, 46–85 years), median follow-up was 8 months (range, 4–27 months). Twenty-three (82%) were patent on 4-month cystoscopy, and these patients had a history of radiation. All patients with a history of PFUI were patent on a 4-month cystoscopy. Two patients were managed with a single dilation, one underwent open urethroplasty, one underwent redo endoscopic repair for a bladder neck recurrence, and one elected to remain on self-catheterization. Sixteen (57%) have gone on to receive an AUS. Three (10%) patients required cystectomy with urinary diversion. One for refractory hematuria due to radiation cystitis, one for refractory symptomatic bladder neck necrosis with sloughing, and one for delayed urosymphyseal fistula in the setting of extensive radionecrosis of the bladder neck. All had patent membranous urethra at the time of cystectomy. Cystoscopy images for a patient before and after EBMGU with dorsal graft onlay are demonstrated in Figure 2.

Figure 2 Comparison of membranous stricture before and after endoscopic buccal urethroplasty. (A) Membranous stricture prior to endoscopic buccal urethroplasty. (B) Cystoscopy at 4 months post op with patent urethra and well incorporated graft along the dorsal membranous urethra.

Discussion

Membranous male urethral stricture disease remains challenging to manage, and one must balance the desire for a successful outcome with the morbidity of procedure. Given the high risk of urinary incontinence following repair and the difficult nature of repairing the deep pelvic urethra, optimal management can be debated and is often on a case-by-case basis. While open repair remains the gold standard, the operation is technically challenging and not all patients are candidates for surgery. Complications include extravasation of urine and sexual dysfunction due to compromised blood supply. While balloon dilation, including drug-coated devices offers a less invasive approach to management, the data available suggests less durable long-term success rates. EBMGU provides an alternative option in the treatment armamentarium when managing membranous urethral stricture disease. Here within, we describe the preoperative provisions, surgical techniques and tips, postoperative considerations, and outcomes for male patients who underwent EBMGU for membranous stricture disease at a single institution.

Based on short-term outcomes, EBMGU appears to provide urethral patency in 82% of patients. All five patients with obliterative strictures that were treated with EBMGU had patent urethras at the time of 4-month cystoscopy. As we further refine our technique and selection criteria, we anticipate that long-term success rates may be even higher. The majority of patients in the present cohort had a history of radiation for prostate cancer. The membranous urethra is invariably affected by radiation delivered to the prostate due to its close proximity, and this has important implications when discussing the repair of membranous urethral strictures. First, risk of stress urinary incontinence is higher when the stricture involves the urinary sphincter. Patients are counseled appropriately, and many will go on to undergo AUS following successful urethroplasty. Among the patients who underwent EBMGU, 57% went on to AUS placement. Second, radiation leads to poor tissue quality and may in theory compromise graft incorporation. We had four (14%) patients lose part or all of their graft following EBMGU, suggesting graft incorporation remains overall excellent, even in a population where the majority of patients received prior radiation to the prostate.

There are potential advantages to this approach when treating membranous urethral stricture disease. The spongiosum and urethra are not transected. As such, there is overall less concern for extravasation of urine during healing. Additionally, there is a theoretical preservation of urethral and bulbar artery blood supply. Additionally, given the minimally invasive nature of the approach, patients who are not candidates for an open repair due to significant comorbidities may be a candidate for EBMGU.

A severe consequence of radiation is radionecrosis and formation of calcifications. Through refinement of selection criteria, we have learned that men with significant evidence of radiation damage, including radionecrosis and/or calcifications are at higher risk of complications following EBMGU, and this likely holds true for other urethroplasty surgeries. There were 5 total failures at the time of the 4-month cystoscopy, two of which were associated with calcifications at the time of EBMGU. One developed recurrence at the bladder neck while the other developed delayed urosymphyseal fistula in the setting of extensive radionecrosis, and both required cystectomy for definitive management. We are now more cautious about offering EBMGU to these patients. When present, we first attempt to stabilize the necrosis with transurethral incision and transverse mucosal realignment (10). If this fails to resolve radionecrosis of the bladder neck, we are more likely to offer early cystectomy. Figure 3A depicts significant radionecrosis and mucosal sloughing within the urethra, as such this is a patient we would be more likely to offer upfront cystectomy to. When significant radionecrosis is absent, graft uptake is excellent (Figure 3B).

Figure 3 The presence of urethral radionecrosis negatively impacts graft incorporation. In patients with radionecrosis and mucosal sloughing of the urethra (A), we are less likely to recommend endoscopic buccal urethroplasty due to the poor vascularity of this tissue. Excellent ventral graft uptake is seen when radionecrosis is absent (B).

This report on our experience and outcomes with EBMGU has limitations. All surgeries were performed by a single surgeon. The study has limitations inherent in a retrospective analysis, and the cohort is small. Median follow-up is only 8 months, with longer term follow planned as the data becomes available. Only patients with a 4-month cystoscopy were included. The majority of failures occurred by the time of the 4-month cystoscopy, suggesting that patients who are patent at the time of the 4-month cystoscopy are likely to remain patent. Given the small sample size and overall low failure rate, we cannot assess what risk factors contribute to EBMGU failure. The technique has evolved over time, and with continued refinement there are small differences in the surgical technique used in early patients compared to patients operated on more recently. While this technique seems to be highly reproducible, to the best of our knowledge, few urologists are currently utilizing it, so further assessment of its reproducibility is necessary.

Conclusions

EBMGU appears to be an effective strategy for management of membranous stricture disease, including patients with radiation, PFUI, and obliterative strictures. We noted a success rate of 82%, with a minimum 4-month follow-up. Of the patients, 57% underwent successful placement of an AUS, while 7% (2 patients) required cystectomy due to radiation-related bladder complications near the membranous urethra. Additional follow-up will help determine the long-term success and identify the most suitable patient population for this procedure.

Acknowledgments

None.

Footnote

Provenance and Peer Review: This article was commissioned by the Guest Editor (Lucas Wiegand) for the series “Minimally Invasive Treatments for Urethral Stenosis” published in Translational Andrology and Urology. The article has undergone external peer review.

Reporting Checklist: The authors have completed the SUPER reporting checklist. Available at https://tau.amegroups.com/article/view/10.21037/tau-24-430/rc

Peer Review File: Available at https://tau.amegroups.com/article/view/10.21037/tau-24-430/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-24-430/coif). The series “Minimally Invasive Treatments for Urethral Stenosis” was commissioned by the editorial office without any funding or sponsorship. The authors have no other 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 and its subsequent amendments. Written informed consent was obtained from the patient for publication of this article and the accompanying images. A copy of the written consent is available for review by the editorial office of this journal.

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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