Introduction

Urethral stricture disease (USD) is a narrowing of the lumen of the urethra secondary to spongiofibrosis of the surrounding corpus spongiosum.¹ USD most commonly involves the bulbar urethral segment of the urethra. Etiologies of bulbar urethral strictures vary (traumatic, iatrogenic, idiopathic or inflammatory/infectious) as does management: endoscopic vs surgical repair. We have seen a shift away from the palliative repeat maneuvers of dilation and incision to more definitive reconstructive techniques. Herein, we aim to outline the current patterns of management in USD of the bulbar urethra (see Figure).

Dilation, Direct Vision Internal Urethrotomy vs Urethroplasty

Figure. Decision tree for management of urethral stricture disease. DVIU indicates direct vision internal urethrotomy; OMG, oral mucosa graft; tEPA, transecting excision and primary anastomosis.

Procedures such as dilations and direct vision internal urethrotomy (DVIU) have been shown to have similar efficacy for primary short bulbar USD.^2,3 The EAU (European Association of Urology) and AUA guidelines include dilation or DVIU for the initial management of short (<2 cm or grade L1S1a), singular bulbar strictures or in the emergent setting of acute urinary retention from USD.⁴ Although less efficacious than the gold standard urethroplasty, dilation or incisions are included as a primary treatment option.^5,6

In consideration of a recurrent bulbar urethral stricture, a randomized controlled trial of urethroplasty vs endoscopic urethrotomy for recurrent stricture disease was performed (known as the OPEN trial). This was the first high-level evidence that favored urethroplasty over endoscopic management with a 48% lower risk of re-intervention (at 4 years follow-up time) when patients underwent urethroplasty.⁷

From a cost-effectiveness standpoint, urethroplasty has furthermore been demonstrated to be safe for outpatient surgery with 70.4% of reconstructive urologists doing so according to a 2019 survey conducted by Hoare et al.⁸

Urethroplasty: Short Bulbar

For short bulbar urethral strictures (<2 cm), anastomotic urethroplasty has been the most commonly employed technique for repair with oral mucosa graft (OMG) reserved for longer strictures. This has traditionally been done in a transecting excision and primary anastomosis, which has been reported to have a success rate of up to 94%-96%.⁹ Recently, there has been debate regarding whether transection of the urethral blood supply would decrease sexual side effects (ie, erectile function, glans sensitivity, penile length, and ejaculatory dysfunction) following urethroplasty. In response to this, a non-transecting anastomotic urethroplasty technique for short bulbar urethral strictures was first introduced by Andrich and Mundy in 2011 with such blood preservation in mind.¹⁰ Although there have been no randomized controlled trials to definitively conclude that vessel-sparing OMG is beneficial for patients, many studies have supported its benefits.^11-13 A randomized clinical trial comparing transecting excision and primary anastomosis vs the vessel-sparing technique is currently underway, known as the VeSpAr trial, to answer this very question.¹⁴

Urethroplasty: Long Bulbar

The standard of care for long bulbar urethral strictures (>2 cm) is a urethroplasty with an OMG. Although fasciocutaneous flaps have been described as substitution tissue coverage for longer stricture segments, these are not commonly used in isolated bulbar urethral structures. When strictures are both long and obliterated, an augmented anastomotic urethroplasty with OMG has been described, which is a transection technique combined with grafting. Although this technique is used when necessary, it was found to be associated with higher stricture recurrence (HR 4.8) over a 78.9-month follow-up period based on a 2020 review by Redmond et al.¹⁵

With OMG urethroplasty being the standard protocol, there has been controversy regarding optimal graft placement: dorsal vs ventral.^16,17 Both are reported to be highly successful. In an attempt to answer this question, a randomized controlled trial of dorsal vs ventral onlay OMG urethroplasty is currently underway (the “DoVe trial”).¹⁸ When oral mucosa is not available, the use of rectal mucosa has shown some promising results as an alternative graft.¹⁹ As our field continues to advance, we will look to tissue engineering and improved matrix for future reconstructive use.

Future Trends

Trends in management of USD are favoring more minimally invasive techniques. Investigational animal studies utilizing liquid mucosa grafts following DVIU are showing some promise, as well as endoscopic suturing techniques.^20,21

Furthermore, in December 2021, the Food and Drug Administration approved a paclitaxel-coated balloon for anterior urethral strictures based on a randomized controlled trial comparing the drug-coated balloon vs conventional dilation for anterior urethral strictures ≤3 cm in length.²² Six months following intervention, those treated with the drug-coated balloon had an anatomical success rate of 75% vs the control arm at 27%. This intervention appears to remain robust through a 3-year follow-up period from a prior interventional nonrandomized study.²³ There is still much to be learned regarding the changes in cellular makeup of urethral scar tissue and how we can attempt to affect the pathogenesis of scar formation/recurrence.