HYPOSPADIAS AND
EPISPADIAS
Hypospadias is a birth defect of the male
urethra that involves an abnormally placed urethral meatus. Instead of opening
at the tip of the glans penis, a hypospadic urethra opens anywhere along a line
(the urethral groove) from the penile tip along the ventral shaft to the
junction of the penis and scrotum or perineum. This is among the most common
birth defects of the male genitalia, second only to cryptorchidism, but the
incidence varies widely from country to country, from as low as 1 in 4000 to as
high as 1 in 125 boys. Hypospadias can occur as an isolated defect or it can be
observed in a complex syndrome of multiple malformations. The global incidence
of hypospadias has increased since the 1980s and this has been attributed to
the wider application of assisted reproductive techniques and to endocrine
disruptors. As it is considered to represent a degree of feminization or male
pseudohermaphroditism (see Plate 1-13), hypospadias has also been associated
with hypogonadism.
In
hypospadias, the genital folds (see Plate 1-3) that normally unite over the
urethral groove from the penoscrotal junction fail to close fully, thus
creating a urethral meatus in a more proximal than normal location. The
urethral meatus in one-half of cases is located just proximal to the normal
meatus but still on the glans penis and is referred to as glanular or
first-degree hypospadias. In penile or second-degree hypospadias, the urethral
meatus is situated more proximally on the penile shaft. In perineal or
third-degree hypospadias, the urethral opening is proximal to the penile shaft
and is observed on the scrotal or perineal skin.
With
hypospadias, the prepuce is usually redundant and forms a hood over the glans.
In most cases, the urethra and corpus spongiosum fail to form normally, which
results in a downward penile curvature (chordee) due to fibrous bands on the
ventral undersurface. The scrotum may be bifid, with maldescended testes in some
instances. Early correction of the chordee is important so that the penis and
corporal bodies may grow straight. Androgens may be a valuable adjunct before
surgery. Circumcision should not be performed because the hooded foreskin may
be of use later as a source of flap tissue in urethral reconstruction.
Epispadias
is a rare anomaly of the male urethra and is usually associated with exstrophy
of the bladder (exstrophy–epispadias complex). It occurs in around 1 in 120,000
male and 1 in 500,000 female births. In this condition, the urethral orifice is
observed on the dorsal penis just proximal to the glans (glanular epispadias)
or is observed as an opening under the symphysis pubis in complete epispadias.
Epispadias is a partial form of a spectrum of failures of abdominal and pelvic
fusion in early embryogenesis. While epispadias occurs in all cases of exstrophy,
it can also appear in isolation as the least severe form of the complex. It
occurs as a result of defective migration of the genital tubercle primordia to the cloacal
membrane during the fifth week of gestation.
In this
condition, the floor of the urethra is observed as a groove on the dorsum of the
penis that is lined by mucosa and demonstrates openings of the periurethral
glands (see Plate 2-12). The partial prepuce is located on the ventral penis.
The epispadiac penis tends to curve upward and press against the mons pubis.
The membranous and prostatic urethrae in most cases of complete epispadias
are widely patent with incomplete development of the external sphincter muscle
so that patients are commonly incontinent. The symphysis pubis may be well
formed or may only be a fibrous band of tissue. Causes of epispadias are still
unknown but theories that postulate endocrine disruption, polygenetic
predisposition, and viral infection have been put forth. Urinary tract
reconstruction is necessary to restore continence and full penile function.
