Sonographic evaluation of male anterior urethral strictures: Correlation with retrograde urethrography – A review

Abstract

In general, the term urethral stricture refers to a fibrous scarring of the urethra caused by collagen and fibroblast proliferation.^1-3 The scarring process can extend through the tissue of the corpus spongiosum into adjacent structures and this associated scarring in the surrounding corpus spongiosum is known as spongiofibrosis.^1,4 Contraction of this scar reduces the width of the urethral lumen. Bulbar urethral strictures represent the overwhelming majority of cases, while prostatic urethral strictures are rare.⁵ The causes of anterior urethral strictures may be inflammatory (e.g., infectious urethritis, balanitis xerotica obliterans), traumatic (straddle injury, iatrogenic instrumentation) or congenital.^1,6 However, most urethral strictures are the result of infection, instrumentation or other iatrogenic causes.1 The most common external cause of traumatic stricture is straddle injury.^1,7 The male urethra is longer than that of the female and traverses through several anatomical structures such as the prostate, urogenital diaphragm, and corpus spongiosum of the penis, it is therefore more vulnerable to injury and stricture than the female urethra.^1,8 Inflammatory strictures associated with gonococcal urethritis have become less common despite the fact that gonococcus remains the most common sexually transmitted disease.1 In developing countries, infection is the predominant cause of anterior urethral stricture, unlike in the developed world where trauma is the predominant cause.^9-13 Iatrogenic trauma to the urethra may result from pressure necrosis at fixed points in the urethra from indwelling catheters.¹ Instrumentation-related strictures usually occur in the bulbomembranous region and, less commonly, at the penoscrotal junction.¹ Congenital hypospadias could be associated with urethral stricture, and following repair of hypospadias, there is an increased likelihood of post-surgical stricturing.¹⁴
There is currently progressive increase in the incidence of urethral stricture due to the increased number of permanent catheter bearers, the surge of sexually transmitted diseases, and misuse of transurethral diagnostic or therapeutic instrumentation.^1,6