Epispadias

Epispadias refers to a rare birth defect of the urethra found in males and, more rarely, females assigned at birth, in which the urethral tube fails to tubularize as usual. As a result, the urethral opening is found on the dorsal side rather than the tip of the penis in those assigned male at birth and towards or above the clitoris in those assigned female at birth. In epispadias, the space between the expected and the actual urethral opening remains open.  

Of note, the penis has a different definition of dorsal and ventral relative to anatomical standards. Typically, on the human body, dorsal, or, posterior, refers to the back portion of the body and ventral, or anterior, to the front part. However, when referring to the penis, the dorsal side describes the top of the penis and ventral refers to the bottom side. 

Epispadias is part of the bladder exstrophy-epispadias-complex (BEEC), which is a spectrum of genitourinary malformations. Depending on the severity, BEEC may involve the urinary system, musculoskeletal system, pelvis, abdominal wall, genitalia, and sometimes, the spine and anus. Isolated epispadias is the mildest form and found more frequently in individuals assigned male at birth. Nonetheless, epispadias is rarely identified without other malformations of the BEEC.  

Hypospadias refers to an abnormal opening ventrally on the penis or close to/within the vaginal orifice. On the other hand, epispadias refers to an abnormal opening dorsally on the penis or towards/above the clitoris.  

To help recall the difference, note the words’ Greek origins. The prefix hypo- means below and epi- means above, whereas the suffix -spadias refers to the opening of the urethra.  

Of the two, hypospadias is more common and is associated with other conditions such as chordee, which is when the penis has a hook shape and curves (usually downward); inguinal hernias, which are protrusions of abdominal contents through the inguinal canal; and cryptorchidism, which is the failure of one or both testes to descend into the scrotum. Epispadias is usually associated with bladder exstrophy, where the bladder protrudes through the abdominal wall. In individuals with female genitalia, a bifid clitoris, which is when the clitoris itself is divided into two parts, can often be identified along with epispadias. 

The precise cause of epispadias is not fully understood but appears to be related to fetal exposure to low levels of androgens and estrogens. 

Epispadias is the result of malformations during embryogenesis, starting from the sixth week of gestation when the genital tubercle (i.e., a fetal tissue responsible for the development of the reproductive system) grows in a posterior direction towards the rectal area instead of in the cranial direction. This leaves the urethral tube on the dorsal side of the genital tubercle, which results in epispadias. 

Anatomically, in individuals with male genitalia, epispadias can occur in three areas: penopubic, where the base of the penis and the abdominal wall come together; penile, which is somewhere along the shaft of the penis; and glanular, or near the tip of the penis. The least severe is glanular, and the most severe is penopubic. 

In individuals with female genitalia, development is stimulated by estrogens. The genital tubercle elongates and forms the clitoris in addition to the urethral folds, which create the labia minora and the vestibule. In the thirteenth week of gestation, the urethra is formed and is situated anterior to the vaginal canal. Epispadias results if the urethra develops too far anteriorly. 

Differential diagnoses involve considering various possible conditions that could be causing symptoms and then ruling out each one through use of history, clinical evaluation, diagnostic tests, and critical thinking. This process helps to narrow down the list of potential diagnoses to determine the most likely cause of the symptoms. 

Differential diagnoses can be broken down into four categories: most likely, less likely, least likely, and can’t miss. Most likely diagnoses are conditions most probable based on symptoms and clinical presentation. Less likely diagnoses are not as probable but should still be considered. On the other hand, least likely diagnoses can be considered if other, more probable conditions are excluded. Finally, can’t miss diagnoses are less common but critical to promptly identify and treat as they can lead to severe consequences.    

In order to treat epispadias, a surgical approach carried out in tertiary care center is typically recommended. The goal is to reconstruct the urethra, close the defect, allow normal urinary flow, and ultimately achieve proper anatomical functions and cosmetic appearance.  

In individuals assigned male at birth, a single surgery is often done for isolated epispadias, with staged surgeries preferred in more complex cases, in which additional reconstructions are needed. In females assigned at birth, surgery is typically less challenging and traditionally performed in a 2-step approach. The procedures are usually done within the first 2 years of life, with the timing depending on the associated defects and the chosen techniques.