Introduction

Posterior urethral stenosis (PSU), or posterior urethral stricture, is when the posterior urethra narrows, leading to issues. It accounts for 7.8% of all cases, making it relatively rare.¹⁸ It can be present from birth, resulting from trauma, or from treatment for other conditions in the pelvis which is the most common cause. These include catheterisation, pelvic fractures and various treatments for prostate cancer/hyperplasia.¹⁸

The posterior urethra is approximately 5cm long, extending through the urogenital diaphragm, through the prostate in men and then to the neck of the bladder.²¹ In females, the urethra is much shorter so it is not segmented into a posterior and anterior section, though rarely, stenosis can occur.²² Treatment is necessary as persistently untreated PSU can lead to issues like permanent bladder and kidney damage, recurring urinary tract infections and urine filling into the kidneys from the bladder (vesicoureteral reflux).²³

In the following article, we will explore the different methods for treatment and prevention of PSU.²¹ Posterior and anterior urethra in male anatomy.

Diagnosis and tests

Diagnosing the issue is the first step to getting better. A physician may diagnose the issue based on your symptoms, medical history and a physical exam.  PSU is not often seen in those aged 20-70, making it unlikely that a large proportion of the population will develop this condition.¹⁸

X-rays, ultrasounds, cystoscopy, urinalysis, retrograde urethrograms and voiding cystourethrograms may all be used to help diagnose the issue, though may be unnecessary if enough evidence is present without them. 

Treatment and management 

Many factors affect how PSU is treated, such as how it was caused, how long the stenosed urethra is and the presence of scar tissue. The average PSU length is 4.15cm, although certain comorbidities like lichen sclerosus can make this much longer.^18,19

For asymptomatic PSU which was discovered by chance, perhaps during catheterisation difficulty, or when the urethra is still open more than 91-93% of its original size, surveillance is observed for a few weeks until the issue is resolved. The resolution may only occur in 12% of cases in PSU where the urethra is open 90% of its original size over approximately 2 years, so where there is a 10% reduction in the lumen, intervention may be prioritised.²⁵

Urethral dilation

This is when narrow tubes are inserted into the urethra one at a time, getting slightly bigger each time to help widen the PSU. Alternatively, a narrow balloon may be inserted and then slowly inflated to achieve the same effect.

Direct-vision internal urethrotomy (DVIU)

This is a 30-minute procedure that will require partial or total sedation. A narrow tube tipped with a tiny camera is inserted into the urethra.²⁸ A small attachment may be used to remove any scarring to widen the PSU, using a blade, heat, or a laser. The area can then be re-examined, and a catheter tube may be placed within the urethra.

 Urethral stents may also be inserted to keep the urethra open, which have been shown to help maintain urethral function for longer than urethral dilation or DVIU alone.²⁶ However, the recurrence of PSU can be quite high, so DVIU is normally reserved for patients for whom it is most suitable, for example, those who need time before a permanent urethroplasty can be carried out.²⁸

Urethroplasty

Posterior urethroplasty can be used for PSU, especially for those induced from traumatic injury. They are used to surgically cut out part of the urethra that is damaged, or to widen the part that is narrowed.²⁷ They are successful in more than 80% of cases, but there are many factors to consider before surgery is decided.²⁵ For example, PSU in those with nervous erectile dysfunction can be operated on but those suffering from erectile dysfunction due to blood supply issues should first have another surgery to correct this before a urethroplasty to prevent tissue death.²⁷ 

Urethroplasty is also the best option for irradiation-induced PUS, which could result from prostate cancer treatment. Typically, this may be carried out 3-6 months after the initial PSU is discovered to let the scarring mature and any clotted blood pools from injury to fully dissipate.²⁷ Regardless, successful surgeries have been carried out at 3-6 weeks post-discovery of PSUs, so long as the perineum is pliable and soft, and there is no swelling, clots, or other unstable injuries that could prevent the patient from lying in the correct surgical position.²⁷

Most likely you will need repeat treatment if it reoccurs. Reoccurrence of PSU can lead to a longer portion of your urethra forming part of the stenosis, so it is important to try and follow guidelines to prevent reoccurrence.¹⁸ 1 week for urethral dilation and 2-3 weeks for urethroplasty to feel better. 

Prevention

Although not completely, PSU can be prevented in some cases by preventing a pelvic fracture from occurring. This can be achieved in a few different ways by preventing injury and maintaining good relative bone health.

Preventing injuring

• Always wear a seatbelt when travelling in a vehicle 
• Using appropriate padding during high-impact sports e.g. cricket, football and martial arts)

Maintain good bone health

There are several ways to maintain good bone health to limit pelvic fractures from occurring. One of these is by including enough vital nutrients in your diet, like calcium. Calcium is absorbed from our diet, adequately done so in the presence of vitamin D.¹ If sufficient levels of vitamin K are present, then this calcium will help mineralize bones and strengthen them.² Therefore, it is best to eat foods or take supplements containing these vitamins and minerals together to maximise bone health.

Foods rich in calcium include:³

• Green-leafed vegetables
• Yoghourt and cheese
• Dried mango, figs and raisins^{4, 5, 6}
• Tofu
• Milk

Foods rich in vitamin D include:³

• Mackerel, sardines, herring and other oily fish
• Liver
• Red meat like lamb and beef
• Egg yolks

Foods rich in vitamin K include:⁷

• Spinach
• Kale
• Broccoli
• Brussel sprouts
• Fermented soybeans or soybean oil
• Lettuce
• Cabbage

At times, bone may be breaking down too much within the body. This can lead to fragile bones which may snap easily, thus potentially leading to PSU. Physicians may prescribe bisphosphonates to prevent bone loss. These drugs bind and cause bone resorption cells to die or slow down, so more bone is built up over time instead of broken down.⁸ This can lead to stronger, better mineralised pelvic bones over time, thus limiting the risk of pelvic fractures and PSU. This drug can lead to some side effects, so it is best to consult a physician and only take them when prescribed.⁹

Carrying out bone health activities to help strengthen bones through the introduction of microfractures into the bone. This leads to bone remodelling, which will strengthen your bones in the long run. These exercises include:

• Tai Chi¹¹
• Yoga¹²
• Brisk-walking for half an hour, 3+ times a week¹³
• Dancing¹⁴
• Racquet Sports like badminton and tennis¹⁷
• Weight lifting¹⁶
• Resistance band training¹⁵

Making good dietary lifestyle choices to protect bone density, such as limiting excessive alcohol intake and stopping smoking can also improve bone health.³

Bone remodelling takes time, taking on average three to four months. Therefore, it is important to continue to make good choices, and over time the results achieved will benefit you.¹⁰ Getting advice on prevention techniques from a healthcare provider is best to prevent any other abnormalities from occurring depending on your unique physiological profile. If any symptoms of PSU reoccur, again see your healthcare provider as this may require retreatment.

Urethral catheterisation can cause injuries in the posterior and bulbar urethra in 0.32% of patients, which can result in PSU in some cases, especially when it is inserted incorrectly.²⁴ Proper training of staff can also prevent help prevent PSU. Sexually transmitted infections can also cause urethral damage, so using protection and seeking help quickly when abnormalities are suspected can also prevent PSU from developing.²⁴

Urgent medical help should be sought if you are unable to urinate, if there is blood in the urine, if there is more pain when you urinate or if there are any signs of infection. 

Summary

Posterior stenosis or stricture of the urethra (PSU) is a condition where the tube that carries urine from the bladder out of the body becomes scarred and narrowed in the region where it leaves the bladder and passes through the prostate in males. It can be caused by a variety of factors, some of which may be unknown. It may be observed without further intervention, or minimally invasive procedures like urethral dilation or urethrotomy may be performed although there is a risk of PSU reoccurrence. In worse cases, invasive surgery in the form of urethroplasty may be carried out. Preventing PSU can be achieved through preventing pelvic fractures and infections, though the occurrence is relatively rare in the first place.