Urethral stricture disease causes significant voiding problems that hinders a patient’s normal way of life. Treatment for patients suffering from this disease varies depending on the type of stricture, the etiology of the stricture, and the patient’s overall health and goals. Surgical reconstruction yields low failure and high satisfaction rates.
The urethra is a tubular structure that helps transport urine out of the bladder during urination. Patients who have strictures (or narrowing) of their urethra can have significant and bothersome symptoms including a weak force of stream, straining during urination, incomplete bladder emptying, frequency (having to void often), urgency (abnormally strong sensation to urinate), hesitancy (difficulty initiating void), and sometimes hematuria (blood in the urine). Serious consequences of untreated urethral strictures include urinary retention (inability to urinate), recurrent urinary tract infections, abscesses (collection of pus), fistulas (connection between urinary tract and other tissue like skin or rectum), bladder dysfunction, and even kidney failure.
The urethra is about 8-10 mm in diameter and variable in length. The urethral meatus is at the tip of the penis, and the urethra travels within the corpus spongiosum, a tubular structure within the penis that lies just beneath the paired corpora cavernosa (two cylindrical structures within the penis that fill with blood during erections). The male urethra is functionally divided into two segments: the anterior and posterior urethra. The dividing line is a group of sheet-like pelvic muscles termed the urogenital diaphragm. The muscle immediately surrounding the urethra is called the external striated urethral sphincter. The anterior urethra is further divided into the fossa navicularis (most distal 1-2 cm of urethra), penile urethra, and bulbar urethra (segment of urethra within the largest portion of the corpus spongiosum; it is surrounded by the bulbospongiosus muscle). The posterior urethra includes the membranous urethra (segment of urethra at the level of the pelvic diaphragm) and prostatic urethra (segment of urethra within prostate and closest to the bladder).
The blood supply to the anterior urethra is derived from the internal pudendal artery. This artery divides into the paired bulbar and dorsal arteries. The bulbar arteries enter the corpus spongiosum at the level of the bulbar urethra, providing antegrade blood flow to the urethra. The dorsal arteries travel along the dorsum of the corpora cavernosa and provides retrograde blood flow via the glans. In addition, there are circumflex branches from corpora cavernosa (aka perforatoring arteries) that feeds the urethra dorsolaterally.
The blood supply to the posterior urethra is derived from the inferior vesical artery.
Causes of urethral strictures vary greatly. In general, an injury to the urethra or corpus spongiosum can lead to stricture formation. Straddle type traumas–like those incurred during fence climbing, horse riding, or bicycling–are common causes. Other etiologies include instrumentation such as cystoscopy (tubular camera inserted thru urethra to look at urethra and bladder) and catheterization (tube placed into bladder for bladder drainage). Inflammation can also cause strictures. Examples include gonococcal and non-gonococcal urethritis and lichen sclerosis. Strictures may also be congenital in origin, but these are rather rare. Management of inflammatory urethral stricture disease often depends more on stricture number, length, location, and severity than etiology. Most strictures are of the anterior urethra. Complicated strictures like those associated with lichen sclerosis, prostate therapy, urethral stenting, hypospadias, and pseudo-strictures seen in pelvic fracture urethral distraction defects (PFUDDs) are managed much differently.
DIAGNOSIS AND EVALUATION
As with any medical problem, performing a thorough history and physical is required. Specific assessment of a patient’s voiding symptoms, neurologic history, traumatic history, and surgical history aids in identifying urethral stricture disease. Additional diagnostic tools include urinalysis (analysis of the urine to identify infection and/or blood), uroflowometry (tool that measures volume and rate of bladder emptying), and bladder ultrasounds (device that determines how well a patient empties their bladder after voiding). Uroflowometry is frequently used in patients suspected of having strictures. A flow rate for a normal man is 15ml/second and the uroflow graph should look like a bell curve. For patients with strictures, the flow rate is often < 5ml/sec and the uroflow graph is flat. More invasive tests include cystoscopy and retrograde urethrogram (RUG: radiographic study that involves injecting contrast thru the urethra). These quickly identify the location, length, number, and severity of urethral strictures. On occasion, contrast during RUG can fail to show the urethra proximal to the stricture. Voiding cystourethrograms (VCUGs) are performed in this situation. Combination RUG and cystogram is performed for PFUDDs. On occasion, it may be helpful to endoscopically examine the urethra with a narrow caliber ureteroscope to assess for membranous urethral involvement since membranous strictures are managed differently than other strictures.
Treatment options depend on many factors, including stricture severity and location, as well as the patients’ goals and overall health. Short strictures could be managed with urethral dilations, direct visual internal urethrotomies (DVIU), urethral stents (device that attempts to keep the stricture open), or surgical reconstruction. Dilations, DVIUs, and stenting can often be accomplished endoscopically (surgery performed thru the urethra with cameras and special tools without making any skin incisions) in less than 30 minutes. Surgical reconstruction involves incising the perineum (area of skin between the scrotum and anus) to identify and repair the strictured urethra. These surgeries are more involved and have higher associated risks. Patients unfit for open surgery often undergo repeated dilations or DVIUs. Younger and healthier patients will choose surgical reconstruction because it offers much better long-term success rates than endoscopic surgery, thereby obviating the need for repeated dilations and urethrotomies.
To be absolutely clear, DVIU and dilation for a short bulbar urethral stricture (< 2cm) has a long-term failure rate of about 50%. The failure rate increases for longer strictures and strictures of the penile urethra. If the first DVIU/dilation is unsuccessful, a subsequent DVIU/dilation will yield very poor results and is not recommended. Urethroplasty should therefore be offered if the first DVIU/dilation fails.
Strictures that are long or more complex, like those seen in patients with prior hypospadias repairs/urethroplasty, panurethral strictures, pelvic fracture urethral distraction defects, restenosis after urethral stenting, and strictures associated with prostate therapy, require a flexible reconstructive approach 1 . The least invasive option is cystostomy (or suprapubic (SP)) tube placement—a short surgical procedure that results in catheter drainage of the bladder thru the patient’s lower abdomen. Catheters are changed once a month but patients will have a tube from their abdomen for as long as they leave the urethral stricture untreated. Perineal urethrostomy creation is a surgical connection made between non-strictured urethra and perineal skin. This is more invasive than SP tube placement, but patients tolerate this well since they don’t have to deal with catheters and no longer have to strain to urinate.
Urethral dilation and urethrotomy
Urethral dilation is performed by cystoscopically placing a wire past the stricture and into the bladder. Tubular shaped dilators with a hole in the center are inserted over the wire to mechanically open the stricture. Balloon dilators may also be used but risk damaging neighboring healthy urethra as this tissue is also subjected to the pressure of the balloon dilator. DVIUs are done with an endoscopic scalpel or a holmium laser with equal success rates. Incisions are made thru the scar until the cystoscope can be negotiated across the stricture and into the bladder. The long-term outcomes between dilations and urethrotomies are very similar and have a high failure rate. Dilation and urethrotomy should therefore be considered temporizing measures for planned definitive surgical reconstruction.
An alternative and preferred approach to endoscopic management involves the use of a small 6F ureteroscope (cystoscopes are 17-20F) to visual inspect the urethra to determine the number, quality, and length of the stricture.
Short, thin, translucent strictures (i.e. non-inflammatory congenital strictures) can be treated with DVIU/dilation with good results.
Urethral stenting is initially very appealing since stents are easy to place and patients have minimal immediate complications and complaints. However, with longer follow-up, a high percentage of patients develop pain, infection, stent migration, restenosis (re-narrowing of the urethra), and stone formation. Urethral stents have been abandoned by most experts. Official contraindications for using urethral stents include strictures in the penile urethra, strictures longer than 3 cm, patients under age 30, and PFUDDs.
Anterior urethral strictures are generally treated with anastomotic urethroplasties, onlay/substitution urethroplasties, or staged Johanson urethroplasties2. Short < 2cm bulbar strictures are treated with a traditional transecting or non-transecting anastomotic urethroplasties. This involves incising the perineum to expose the strictured segment, removing the segment, and then reconnecting the healthy urethral tissue. This procedure is also called and excision and primary anastomosis, or EPA urethroplasty. The non-transecting anastomotic urethroplasty was popularized by Dr. Anthony Mundy3. It involves circumferentially dissecting the bulbar urethra and making a dorsal stricturotomy that is then closed horizontally (Heineki-Mikulics fashion). If the stricturotomy cannot be closed, then a dorsal onlay urethroplasty is performed (details below). Patients must be counseled about the risk of sexual complications (cold, soft glans, decreased sensation, ejaculatory dysfunction) from the EPA procedure. Some authors favor avoiding urethral transection at all costs as a result of these sexually-related risks.
For bulbar strictures 2 – 4cm in length, onlay/substitution urethroplasties are the procedure of choice. They frequently require buccal mucosal graft (tissue from inside the cheek; BMG) because it has similar properties to urethral tissue: the absence of hair, pliability, and chronic exposure to a wet environment. Furthermore, harvesting the graft is easy and well tolerated with minimal risks.
A second incision in the perineum exposes the urethra and allows us to locate and cut the strictured segment longitudinally. We then suture the graft to the urethra laterally, dorsally, or ventrally to tubularize the urethra. Because the bulbar urethra is surrounded by a good amount of corpus spongiosum tissue, ventrally placing the graft requires the least dissection and provides excellent long term results. Due to the minimal dissection required via this technique with resultant lower sexually related complications, we consider and prefer this technique for all proximal bulbar strictures less than 4cm.
For distal or mid bulbar urethral strictures, the robust ventral corpus spongiosum tissue is not available for ventral onlay BMG urethroplasty. We therefore prefer dorsal onlay BMG urethroplasties for these strictures. In attempts to preserve the lateral circumflex artery blood supply, we dissect only on one side of the urethra to expose the underlying corpus cavernosa (the graft recipient site) and perform a dorsal onlay.
Bulbar strictures > 4cm have a lower success rate with onlay urethroplasty (about 80% vs 90% for shorter strictures). In attempts to reduce the failure rate, we are now performing double-sided BMG urethroplasties (dorsal inlay and ventral onlay) for these longer strictures. This was popularized by Palminteri et al4for shorter and more severe bulbar strictures. The mean stricture length treated with the double-sided urethroplasty was 3.3cm, and 88% of patients were stricture free at 49 months follow up.
Johanson staged urethroplasty is no longer favored for long strictures unless it is associated with prior hypospadias repair or urethrocutaneous fistulas. The technique involves cutting thru the entire ventral aspect of the stricture and overlying penile skin until the remaining urethral opening is of satisfactory calibre. Surgeons then sew the edges of the remaining urethral flat plate to its neighboring skin. Patients therefore urinate out of an opening at the base of their penis or scrotum. If the urethral plate is inadequate due to severe scarring, it is excised, exposing the underlying corpora cavernosa. BMG, lingual mucosa graft, or full thickness skin graft is then secured onto this with absorbable suture. After 6 months, a second stage Johanson procedure is performed, which is retubularizing the urethra by using healed graft and skin lateral to the urethral plate and sewing it in the midline. For patients with lichen sclerosus, using genital skin leads to recurrence of stricture and is therefore not favored.
Fasciocutaneous flaps (especially flaps involving penile skin) are also avoided by some experts for treatment of urethral strictures since it also disrupts the sexual function of the penis and can be technically more difficult. That being said, flaps have been used successfully for penile urethral and longer urethral strictures. The main benefit is that flaps bring their own blood supply as opposed to a graft, which must obtain and develop nutrients from neighboring tissue.
Long and panurethral strictures are preferentially treated with one-sided full length dorsal onlay buccal mucosal graft (BMG) urethroplasty5. This is a technique innovated by Dr. Sanjay Kulkarni from Pune, India and Dr. Guido Barbagli from Arezzo, Italy. This procedure can be seen on YouTube (“video” or “Kulkarni” link in menu bar above). In general, it involves penile inversion, one sided corpus spongiosum/urethral dissection to preserve the lateral blood supply, and dorsal onlay with BMG graft (usually required from both cheeks). Occasionally, lingual grafts are required and can be obtained from the side of the tongue.
Difficult strictures include posterior urethral, long bulbar, and panurethral strictures, as well as those associated with prior hypospadias repair, prior urethroplasty, lichen sclerosis, prostate therapy, or stent restenosis. The techniques described before are alone insufficient for adequate treatment. Definitive reconstructive surgery for these complex strictures requires flexibility and creativity. For example, a combined dorsal and ventral onlay urethroplasty with buccal mucosal grafts may be needed for obliterative bulbar strictures and strictures 4cm and longer. Also, adult hypospadias patients with urethral stricture may need a long dorsal BMG augmentation of the urethral plate during their 1st stage Johanson followed by a 2nd stage Johanson 3-6 months later.
Patients suffering from PFUDDs and stent restenosis are generally treated with scar and stent excision followed by primary reanastomosis with acceptable success rates. Some repairs require proximal corpora cavernosa separation (aka crural separation) and inferior pubectomy (removal of inferior portion of pubic bone) to decrease the distance for anastomosis of the proximal bulbar urethra to the membranous urethra. For patients with bulbar urethral necrosis/stenosis from prior PFUDD treatment, options include enterourethroplasty (using intestine to replace the bulbar urethra), fasciocutaneous tube flap, or prefabricated buccal mucosa dartos or gracilis muscle tube flaps. In the United States, crural separation, inferior pubectomy, and bulbar urethral substitution are rarely required since there are less severe pelvic injuries due to more developed infrastructure and advanced automobile safety technology.
Current Management Summary
Bulbar Urethral Strictures
Urethral stricture disease causes bothersome urinary symptoms that are detrimental to a patient’s quality of life. In severe cases, it may lead to bladder dysfunction and kidney failure. The management of urethral strictures varies widely depending on their etiology, location, length, and severity, as well as patient preference and overall health. Short strictures are generally treated with dilation and/or urethrotomy, with the understanding that most will eventually fail and require open reconstruction. Most patients should undergo no more than one DVIU/dilation followed by urethroplasty for recurrences. Bailout perineal urethrostomy and SP tube placement are also treatment options with overall high patient satisfaction. PFUDDs require scar excision and posterior anastomotic urethroplasty.
1Burks FN, Santucci RA: Complicated urethroplasty: a guide for surgeons. Nature. 2010:7:521-528.
2Zimmerman WB, Santucci RA: A simplified and unified approach to anterior urethroplasty. Nature. 2010:7:386-391.
3Andrich DE, Mundy AR. Non-transecting anastomotic bulbar urethroplasty: a preliminary report. BJU Int 2012;109: 1090.
4Palminteri E, Manzoni G, Berdondini E, et al: Combined dorsal plus ventral double buccal mucosa graft in bulbar urethral reconstruction. European Urology. 2008:53:81-90.
5Kulkarni SB, Barbagli G, Sansalone S, Lazzeri M. One-sided anterior urethroplasty: a new dorsal onlay graft technique. BJU Int. 2009:8:1150-5.