Current management strategies for bladder neck stenosis and vesicourethral anastomotic stenosis

Abstract

Bladder neck stenosis (BNS) and vesicourethral anastomotic stenosis (VUAS) are forms of posterior urethral narrowing, typically resulting from benign prostate surgery and radical prostatectomy, respectively. Cystoscopy confirms the diagnosis, while voiding cystourethrography and retrograde urethrogram help assess disease extent. Magnetic resonance imaging may be useful in evaluating complex or previously irradiated patients. Management should be guided by the etiology, severity, and prior interventions, and ranges from endoscopic management to complex reconstruction or diversion. Endoscopic management is the first-line treatment for non-obliterative disease, typically using dilation or direct vision internal urethrotomy. Adjunctive measures such as clean intermittent catheterization or intralesional agents like mitomycin C may improve durability. Novel strategies, including transurethral incision with transverse mucosal realignment and endoscopic grafting, show early promise. Nonetheless, recurrence rates remain high, particularly after radiation. Reconstruction is indicated for obliterative or endoscopically refractory stenoses in patients with preserved bladder function. For BNS, robotic Y-V or T-plasty offers good patency but variable continence, while buccal grafts should be preserved for recurrences. Reanastomosis remains the standard reconstructive surgery for VUAS, though less effective in irradiated patients. Perineal reanastomosis yields high patency but poor continence, while abdominal access may improve continence at a higher technical cost. This review outlines current management strategies for BNS and VUAS.

Introduction

Bladder neck stenosis (BNS) and vesicourethral anastomotic stenosis (VUAS) are uncommon yet challenging complications of prostatic surgery, trauma, or pelvic radiation (1,2). They develop due to progressive fibrosis of the bladder neck and surrounding tissues, leading to obstruction and associated lower urinary tract symptoms. BNS refers to narrowing of the bladder neck with the prostate in situ, often preceded by endoscopic surgery for benign prostatic hyperplasia (BPH) or radiotherapy. Conversely, VUAS describes scarring at the site of vesicourethral anastomosis following radical prostatectomy (3).

BNS and VUAS share similar clinical presentations and their management often overlaps, tailored to the underlying cause, disease severity, patient health, and prior treatments. Endoscopic treatment is typically the first step, yet recurrence is common and may ultimately lead to major reconstructive surgery or urinary diversion in refractory cases (1). This review provides an overview of the evaluation and management of BNS and VUAS.

Etiology and incidence

BNS

Focal therapies such as high-intensity focused ultrasound (HIFU) have been reported to result in BNS rates as high as 31% (4). In patients receiving radiation therapy for prostate cancer, the combination of external beam radiation therapy (EBRT) and brachytherapy has been shown to increase the risk of BNS compared to either modality alone (5,6). A 10-year propensity-weighted cumulative incidence of BNS has been reported as 9.6% after EBRT, 12% after brachytherapy, and 19% with combined treatment (7). BNS occurs in 0–10% of cases following transurethral procedures for BPH, as reported in a comprehensive analysis by Cornu et al., with no significant difference between resection methods (8).

VUAS

Among surgical treatments for prostate cancer, open radical prostatectomy is associated with a significantly higher risk of VUAS compared to robotic-assisted prostatectomy (6–15% vs. 0–3%) (9,10). Additional salvage prostatectomy has been shown to substantially increase the risk, with the incidence reaching 40% (11).

Diagnosis

Evaluation should begin with a thorough history and clinical examination. Symptoms such as reduced urinary flow, retention, or overflow incontinence should raise suspicion (12). A detailed history can help establish a differential diagnosis, incorporating associated risk factors (13). Patient-reported outcome measures such as urethral stricture symptoms and impact measures (USSIM) may also be used as an additional objective tool (14). Urinalysis should be obtained, and recurrence of malignancy assessed depending on the stenosis etiology and nature of the initial procedure, typically by prostate-specific antigen testing (15). Patients should be evaluated for acute or chronic urinary retention secondary to stenosis using post-void residual measurement, uroflowmetry, renal function testing, complete blood count, and upper urinary tract imaging, as clinically indicated (16). Cystoscopy can confirm the diagnosis, assess external urethral sphincter involvement, and exclude alternative diagnoses (15,17). While retrograde urethrogram (RUG) is helpful in evaluating urethral pathology, it has limited utility for evaluating bladder neck stenosis and may underestimate its extent. Combining RUG with voiding cystourethrography (VCUG) enhances diagnostic accuracy (18,19). Magnetic resonance imaging (MRI) offers detailed anatomic imaging and is valuable in challenging cases, particularly when other modalities are inconclusive (20). It is more accurate than RUG in measuring the length and identifying concurrent complications like fistulas after radiation (21,22).

Endoscopic management

Medical therapies, including α-blockers, 5α-reductase inhibitors, and anticholinergics, have minimal effect and fail to correct the structural pathology, leaving surgical management imperative (6). Immediate urethral or suprapubic urinary catheter placement may be required (16). A temporary indwelling catheter may help improve bladder function in patients with bladder outlet obstruction (23). Further, in the case of the previously irradiated bladder neck, a suprapubic catheter may aid in assessing contracture severity and tissue healing by providing a period of urethral rest prior to staging (24). Endoscopic treatment is the first-line approach for non-obliterative BNS and VUAS, regardless of etiology (Figure 1). However, in cases without initial luminal patency, recurrence is almost inevitable with these modalities (25). In patients who have received radiation therapy, endoscopic intervention should be delayed for at least 12 months to allow tissue stabilization and minimize complications (26).

Figure 1.

Management algorithm for bladder neck stenosis and vesicourethral anastomotic stenosis. BNS, bladder neck stenosis; DVIU, direct vision internal urethrotomy; TUITMR, transurethral incision with transverse mucosal realignment; VUAS, vesicourethral anastomotic stenosis.

Dilation/incision

Dilation and incision are the primary modalities for BNS and VUAS treatment, while transurethral resection (TUR) may be considered for severe or recurrent cases. Dilation can be performed in the clinic and requires cystoscopic or fluoroscopic guidance (17). Direct vision internal urethrotomy (DVIU) involves incising the scar using either a cold- or hot-knife, or holmium laser under anesthesia. Radial incisions at the 3 and 9 o’clock positions are preferred to preserve sphincter function. In contrast, midline incisions at 6 and 12 o’clock should be avoided due to the risk of rectal injury and symphyseal fistula formation, specifically in irradiated patients (27). Upon recurrence, clean intermittent catheterization (CIC) can be offered to motivated patients unwilling to undergo repeat dilations or surgery (2,28). CIC has been shown to reduce stenosis recurrence and may be required only temporarily, particularly in cases of prostate sloughing following focal or radiation therapy (6,29).

Success rates for initial dilation and DVIU are similar, ranging from 44% to 70% (30,31). Holmium laser urethrotomy, which combines precise incision and ablation, may outperform cold-knife incision, TUR, or dilation, with reported single-procedure success rates up to 60% (31-33). A recent meta-analysis found that prior radiotherapy is linked to lower success rates of endoscopic treatment for VUAS, though the effect size was not specified (34). Further, it has been shown that the timing of radiation impacts outcomes of DVIU following VUAS with patients undergoing salvage prostatectomy after primary radiation had the poorest results (80%) compared to those receiving salvage radiation after surgery (71%) (35).

Unlike anterior urethral strictures, repeated endoscopic treatment for BNS and VUAS has been associated with success rates of 75% to 100% (31,36). Nevertheless, these findings come from retrospective studies with varied patient groups and follow-up durations. Smoking and prior treatment failure have been shown to increase the risk of recurrence (31,36).

An emerging endoscopic approach, transurethral incision with transverse mucosal realignment (TUITMR), has shown promising results (37). The technique involves standard incisions at the 3 and 9 o’clock positions with mucosal realignment using a suture and Ti-Knot clip. In a cohort of 19 patients with BNS or VUAS, TUITMR achieved 89% success after a single procedure and 100% after a second, with no significant complications or new incontinence at 6-month median follow-up (37). In a separate series of 13 non-irradiated VUAS cases, recurrence occurred in 31% but was successfully managed with repeat TUITMR (38). Additionally, buccal mucosal grafts have successfully been employed endoscopically for the treatment of membranous urethral stricture (39).

Adjunct therapies

Several adjuvant therapies have been developed to locally deliver drugs at the stenosis site to reduce recurrence. Injection of mitomycin C or triamcinolone into the incised scar may reduce recurrence. Success rates for urethrotomy with mitomycin C range from 58% to 75% after one procedure and 85% to 89% after two. However, rare complications, including urethral or bladder necrosis, have been reported (40-43). Drug-coated balloons (Optilume^®; Urotronic, MN, USA) are designed to deliver localized paclitaxel to reduce fibrosis through mitotic inhibition. Although Optilume^® has shown promise in anterior urethral strictures, its efficacy for BNS and VUAS remains inconclusive, with early studies reporting high recurrence rates (44,45).

Stents

Urethral stenting has been explored for refractory cases. UroLume (American Medical Systems, MI, USA) was designed to stabilize recurrent urethral strictures and stenoses but was discontinued due to high encrustation, migration, and erosionrates (46). Also, stenting carries an 82–100% risk of urinary incontinence for posterior urethral stenosis (47). Current guidelines do not recommend permanent stenting. Early studies on temporary stents such as Memokath^TM (PNN Medical, Kvistgård, Denmark) and Allium^TM (Allium Medical, Caesarea, Israel) suggest low recurrence rates, particularly in non-irradiated patients, though evidence remains limited (48,49).

Finally, patients undergoing endoscopic treatment should be counseled on the risk of post-procedure urinary incontinence. Evidence forming American Urological Association guidelines suggest de novo incontinence has been reported in 0–11% of cases and may be more common in those with prior radiation or prostatectomy (27). Other studies report rates up to 31% (34). These patients should be counseled about the potential need for a subsequent artificial urinary sphincter.

Reconstructive management

BNS

Y-V or T-plasty

Reconstructive surgery may be considered in patients with refractory BNS or VUAS (15). Y-V or T-plasty reconstruction may be utilized for BNS following BPH treatment. Early studies on laparoscopic and robotic T-plasty have shown promising short-term results, with no cases of incontinence (50,51). Conversely, open Y-V plasty has reported patency and incontinence rates of 83–100% and 0–14%, respectively (27) (Table S1). In the robotic Y-V plasty, the bladder is mobilized, the bladder neck is opened anteriorly, and a Y-shaped incision is made at the obstruction site. A V-shaped bladder flap is then advanced into the prostatic urethra. Robotic Y-V plasty is associated with a success rate of 75% and an incontinence rate of 18% (52,53).

Buccal grafting

Buccal mucosal grafts are increasingly used for bladder neck reconstruction at several centers. Subtrigonal inlay techniques have demonstrated promising outcomes in early case series (54). These findings are supported by reports of successful treatment of recurrent BNS using robotic transvesical subtrigonal inlay buccal grafting (55). In addition, robotic transvesical inlay buccal grafting has been shown to be a feasible option following failed Y-V plasty (56).

VUAS

Reanastomosis is an option for patients with obliterative VUAS or stenosis unresponsive to endoscopic treatment and adequate bladder function. However, prior radiation reduces the success of reanastomosis, with patency rates ranging from 60–91% in non-irradiated patients and about 67% in those with prior radiation (57-60). Careful patient selection and the use of tissue flaps may improve outcomes in irradiated patients (61). The procedure can be performed via abdominal, perineal, or abdominoperineal approaches, each with distinct advantages and limitations (62,63).

Perineal approach

The perineal approach allows access to a relatively undisturbed surgical field in post-prostatectomy patients. With the patient in the lithotomy position, a transperineal half-moon incision provides exposure, enabling broad mobilization of the bladder and urethra to achieve a tension-free anastomosis. Corporal splitting and an inferior wedge pubectomy may facilitate this process (25). The stenotic segment is excised, and a reanastomosis is performed using pre-placed absorbable sutures in a “parachuting” technique, with reported patency rates of 91–100% (36). This approach is technically demanding and should be performed in specialized centers. Additionally, its use in patients with prior radiotherapy is discouraged by some authors due to reported poor outcomes, and severe postoperative urinary incontinence is inevitable (25,58).

Abdominal/retropubic approach

The abdominal or retropubic approach offers lower rates of postoperative urinary incontinence (0–58%) compared to the perineal approach, with reported patency rates of 60–91% in non-irradiated patients following radical prostatectomy (27). However, this technique is only suitable for patients without underlying urethral pathology and with adequate bladder function. A major limitation of this approach is the difficulty of the operative field in post-prostatectomy patients due to prior dissection (25). The procedure involves dissection and mobilization of the bladder and bladder neck, excision of the stenotic segment, and reanastomosis.

Buccal mucosal grafting

Dorsal buccal mucosal grafting appears effective in the short-term treatment of refractory VUAS, based on initial reports (64). Single-port robotic surgery represents a growing field, with evidence supporting its application in VUAS reconstruction (65).

Cystectomy and urinary diversion

Urinary diversion or long-term catheterization is reserved for select patients when other treatments are not viable, often due to inadequate bladder capacity, tissue necrosis, fistula formation, or refractory hematuria. Cystectomy may be performed alongside urinary diversion, particularly in irradiated patients, to alleviate persistent hematuria, bladder pain, and avoid pyocystis (66,67). Surgical options include ileal conduit formation, neobladder reconstruction, or continent vesicostomy, which may be performed in open or robotic fashion (6).

Conclusions

Management of BNS and VUAS is challenging with high recurrence rates, often requiring repeated interventions. Treatment should be individualized based on patient factors and prior therapies. Endoscopic treatment is the first-line approach for non-obliterative stenosis, while recalcitrant or obliterative stenoses necessitate reconstructive surgery. Urethroplasty through perineal or abdominal approaches offers definitive management, while urinary diversion should be preserved for patients with no other viable options.

Supplementary

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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.