Urethral strictures. Diagnosis and treatment

Urethral strictures represent the intrinsic and permanent narrowing of the urethral lumen with urodynamic effects and genitourinary complications resulting from obstruction in the path of urine and seminal fluid elimination. In men, urethral stricture refers to a narrowed segment of the anterior urethra caused by a process of fibrosis and scarring of the urethral mucosa and surrounding spongiosum tissue ("spongiofibrosis"). In the male posterior urethra, there is no spongiosum tissue, and the term stenosis is preferred in this location. The definition of meatal stenosis is accepted as a distal narrowing at the level of the meatus, without involving the navicular fossa. There is no universal definition of female urethral stricture. Female urethral stricture is defined by most authors as "a fixed anatomical narrowing" that leads to a reduction in urethral caliber. This reduced urethral caliber is defined as being between <10 Fr and <20 Fr, with most studies defining it as <14 Fr, compared to the normal urethral caliber of 18-30 Fr. In transgender patients, the term stricture is used to define narrowing of the reconstructed urethra despite the absence of spongiosum tissue around it.[1] In men, a marked increase in incidence is observed after the age of 55, with a median age of 45.1 years. The estimated incidence is generally 229-627 cases per 100,000 men [2]. The anterior urethra is most commonly affected (92.2%), especially the bulbar urethra (46.9%) [3]. In women, 2-29% of patients with refractory lower urinary tract symptoms have obstructive flow at the level of the bladder, of which 4-20% will have urethral strictures [4]. There is a significantly increased incidence in women over 64 years of age. In children, most strictures are traumatic: iatrogenic causes account for 27.8-48% and external trauma for 34-72% of cases [1]. Congenital (13%), inflammatory (4%), or postinfectious (1%) strictures are less commonly observed. The bulbar urethra is the most frequently affected part of the urethra [1]. After hypospadias repair, meatal stenosis and urethral strictures are reported in 1.3-20% of cases, depending on the severity of hypospadias and the technique used [5]. There is a significantly higher incidence of this type of stricture in resource-rich countries due to a higher rate of surgical interventions. It has been reported that up to 18% of urethral strictures involving the meatus or navicular fossa are caused by surgical repair of hypospadias, lichen sclerosus, instrumental/traumatic causes, or idiopathic causes. Post-circumcision meatal stenosis has been reported in less than 0.2% of infants undergoing circumcision. In transgender patients ("trans men"), approximately 51% will suffer from a urethral stricture, while in "trans women" (male to female), the incidence is 14.4% [6].