Hypospadias

Hypospadias is a urethral birth defect in which the urinary opening is not located on the head of the penis as it should be. It is the second most common birth abnormality in boys, affecting about one in every 250. The opening (meatus) is on or near the head of the penis (glans) in approximately 90% of cases, referred to as distal hypospadias, while the remainder has proximal hypospadias with a meatus near or within the scrotum. The urethral plate is a shiny tissue that extends from the meatus to the tip of the glans and would have formed the urinary channel.

Causes:

Hypospadias is induced by the urinary channel failing to tabularize all the way to the end of the penis. The exact cause of hypospadias is unknown. Most of the time, hypospadias is the only abnormal finding, but in about 10% of cases, it is part of a syndrome with multiple abnormalities.

An undescended testicle is the most common associated defect, occurring in approximately 3% of infants with distal hypospadias and 10% of those with proximal hypospadias.

A combination of hypospadias and an undescended testicle may indicate a sexual differentiation disorder, in which case additional testing may be recommended.

In the absence of hypospadias, no blood tests or X-rays are usually required in newborns.

Diagnosis:

The characteristic appearance of the penis in newborns is used to diagnose hypospadias. The urinary opening (meatus) is lower than normal, and most boys have only partial foreskin development, lacking the normal underside covering for the glans. The condition is highlighted by the abnormal "hooded" foreskin. However, not all newborns with partial foreskin development have hypospadias because some have a normal urinary opening with a hooded foreskin, a condition known as "chordee without hypospadias."

When the foreskin is normal and there is a concealed hypospadias, the condition is known as megameatus with intact prepuce (MIP). When the foreskin begins to retract during newborn circumcision or later in childhood, the condition is discovered. A newborn with normal-appearing foreskin and a straight penis who is found to have hypospadias after circumcision has begun can have the circumcision completed without fear of jeopardizing future hypospadias repair. After a circumcision, hypospadias is almost never discovered.

Treatment:

Surgery is typically recommended for hypospadias, with the goal of restoring normal appearance and function to the penis. A urinary opening that is not surrounded by glans tissue is more likely to "spray" urine, causing a man to sit to urinate because he cannot consistently stand and hit the toilet. As an adult, a downward curvature of the penis can impair sexual activity. Furthermore, the partially developed foreskin does not appear circumcised or natural.

Depending on the desire of caregivers, surgery extends the urinary channel to the end of the penis, straightens bending, and corrects the foreskin abnormality by circumcision or by repairing it to look normal ("prepucioplasty").

When hypospadias is of the third degree or there are associated birth defects such as chordee or cryptorchidism, the best management can be a more difficult decision. To detect intersex conditions or hormone deficiencies, a karyotype and endocrine evaluation should be performed. If the penis is too small, testosterone or human chorionic gonadotropin (hCG) injections may be given before surgery to enlarge it.

Multiple procedures and mucosal grafting may be required for surgical repair of severe hypospadias. Circumcision should be avoided before repair because preputial skin is frequently used for grafting. Surgery produces unsatisfactory results in a minority of patients with severe hypospadias, such as scarring, curvature, or the formation of urethral fistulas, diverticula, or strictures. A fistula is an abnormal opening through the skin along the course of the urethra that can cause urinary leakage or an abnormal stream. A diverticulum is an "out pocketing" of the urethral lining that interferes with urinary flow and may cause post-urination leakage. A stricture is a severe narrowing of the urethra that obstructs flow. Complication rates for third-degree repair have been reported to be lower in recent years (e.g., fistula rates of less than 5%).