HYPOSPADIAS

HYPOSPADIAS:

Hypospadias is a birth defect of the urethra in the male that involves an abnormally placed urethral meatus (opening). Instead of opening at the tip of the glans of the penis, a hypospadic urethra opens anywhere along a line (the urethral groove) running from the tip along the underside (ventral aspect) of the shaft to the junction of the penis and scrotum or perineum. A distal hypospadias may be suspected even in an uncircumcised boy from an abnormally formed foreskin and downward tilt of the glans.

The urethral meatus opens on the glans penis in about 50-75% of cases; these are categorized as first degree hypospadias. Second degree (when the urethra opens on the shaft), and third degree (when the urethra opens on the perineum) occur in up to 20 and 30% of cases respectively. The more severe degrees are more likely to be associated with chordee, in which the phallus is incompletely separated from the perineum or is still tethered downwards by connective tissue, or with undescended testes (cryptorchidism).

INCIDENCE:

Hypospadias are among the most common birth defects of the male genitalia (second to cryptorchidism), but widely varying incidences have been reported from different countries, from as low as 1 in 4000 to as high as 1 in 125 boys.

There has been some evidence that the incidence of hypospadias around the world has been increasing in recent decades. In the United States, two surveillance studies reported that the incidence had increased from about 1 in 500 total births (1 in 250 boys) in the 1970s to 1 in 250 total births (1 in 125 boys) in the 1990s. Although a slight worldwide increase in hypospadias was reported in the 1980s, studies in different countries and regions have yielded conflicting results and some registries have reported decreases.

CAUSES

Most hypospadias are sporadic, without inheritance or family recurrence. For most cases, no cause can be identified though a number of hypotheses related to inadequate androgen effect, or environmental agents interfering with androgen effect, have been offered. Among the suspected environmental agents have been various chemicals, sometimes termed endocrine disruptors, that interact with steroid receptors. Putative endocrine disruptors include phthalates, DDT, and PCB. A recent questionnaire study of mothers who bore infants with hypospadias reported fivefold higher risk association with vegetarian diet (with plant phytoestrogens the hypothetical link) during pregnancy, and weaker associations with iron supplementation or influenza during early pregnancy [1]. The associations are as yet uncorroborated by additional surveys or other methods.

Prenatal testosterone, converted in the genital skin to dihydrotestosterone, causes migration of skin fibroblasts to fully enclose the urethral groove in fetal males, normally resulting in an enclosed penile urethra by the second trimester of pregnancy. Failure of adequate prenatal androgen effect is therefore thought to be involved in many cases, making hypospadias a very mild form of intersex (undervirilization of a genetic male). Since postnatal androgen deficiency can only be demonstrated in a minority of cases, it has been proposed that transient deficiency of testosterone can occur during critical periods of fetal genital development, due to elevation of anti-müllerian hormone or more subtle degrees of pituitary-gonadal dysfunction. More recently, abnormalities of transcription factors have been proposed.


In a minority of cases a postnatal deficiency of, or reduced sensitivity to, androgens (testosterone and dihydrotestosterone) can be demonstrated. These are often associated with a chordee, and in severe cases a residual perineal urogenital opening and small phallus. This combination of birth defects is referred to as pseudovaginal perineoscrotal hypospadias and is part of the spectrum of ambiguous genitalia. Treatment with testosterone postnatally does not close the urethra.

Genetic factors are likely involved in at least some cases, as there is about a 7% familial recurrence risk.

Rare iatrogenic urethral injuries similar to hypospadias after procedures such as surgery, catheterization, or circumcision have been reported.


TREATMENT

First degree hypospadias are primarily a cosmetic defect and have little effect on function except for direction of the urinary stream. If uncorrected, a second or third degree hypospadias can make male urination messy, necessitate that it be performed sitting, impair delivery of semen into the vagina (possibly creating problems with fertility), or interfere with erections. In developed countries, most hypospadias are surgically repaired in infancy. Surgical repair of first and second degree hypospadias is nearly always successful in one procedure, usually performed in the first year of life by a pediatric urologist or a plastic surgeon.

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

Surgical repair of severe hypospadias may require multiple procedures and mucosal grafting. Preputial skin is often used for grafting and circumcision should be avoided prior to repair. In a minority of patients with severe hypospadias surgery produces unsatisfactory results, such as scarring, curvature, or formation of urethral fistulas, diverticula, or strictures. A fistula is an unwanted opening through the skin along the course of the urethra, and can result in urinary leakage or an abnormal stream. A diverticulum is an "outpocketing" of the lining of the urethra which interferes with urinary flow and may result in post-urination leakage. A stricture is a narrowing of the urethra severe enough to obstruct flow. Reduced complication rates even for third degree repair (e.g., fistula rates below 5%) have been reported in recent years from centers with the most experience, and surgical repair is now performed for the vast majority of infants with hypospadias.

Because of the difficulties and lower success rates of surgical repair of the most severe degrees of undervirilization, some of these genetically male but severely undervirilized infants have been assigned and raised as girls, with feminizing surgical reconstruction. Opinion has shifted against this approach in the last decade because adult sexual function as a female has often been poor, and development of a male gender identity despite female sex assignment and rearing, has occurred in some XY children after reassignment for a more severe type of genital birth defect, cloacal exstrophy.

ASSOCIATED BIRTH DEFECTS:

Mild hypospadias most often occurs as an isolated birth defect without detectable abnormality of the remainder of the reproductive or endocrine system. However, a minority of infants, especially those with more severe degrees of hypospadias will have additional structural anomalies of the genitourinary tract. Up to 10% of boys with hypospadias have at least one undescended testis, and a similar number have an inguinal hernia. An enlarged prostatic utricle is common when the hypospadias is severe (scrotal or perineal), and can predispose to urinary tract infections, pseudo-incontinence, or even stone formation.


EPISPADIAS:

A much rarer and unrelated type of urethral malformation is an epispadias. This is not a problem of the urethral groove or meatus, but a failure of midline penile fusion much earlier in embryogenesis. An isolated opening of the dorsal ("top") side of the penis is rare, and most of these children have much more severe defects, involving a small and bifid phallus with bladder exstrophy or more severely, cloacal exstrophy involving the entire perineum. The cause of this defect of early embryogenesis is unknown but does not involve androgens.


In human anatomy, the perineum is generally defined as the surface region in both males and females between the pubic symphysis and the coccyx.

It is a diamond-shaped area on the inferior surface of the trunk which includes the anus and, in females, the vagina[1]. Its definition varies: it can refer to only the superficial structures in this region, or it can be used to include both superficial and deep structures.

The perineum corresponds to the outlet of the pelvis.



BOUNDARIES:

Its deep boundaries are as follows:[2]
In front: the pubic arch and the arcuate ligament of the pubis
Behind: the tip of the coccyx
On either side: the inferior rami of the pubis and ischium, and the sacrotuberous ligament

TRIANGLES:

A line drawn transversely across in front of the ischial tuberosities divides the space into two triangles:Name Location Contents
Urogenital triangle the anterior triangle in females, contains the vagina
Anal triangle the posterior triangle contains the anus


PERINEAL FASCIA:

The terminology of the perineal fascia can be confusing, and there is some controversy over the nomenclature. This stems from the fact that there are two parts to the fascia, the superficial and deep parts, and each of these can be subdivided into superficial and deep parts.

The layers and contents are as follows, from superficial to deep:
1) Skin
2) superficial perineal fascia: Subcutaneous tissue divided into two layers: (a) A superficial fatty layer, and (b) Colles' fascia, a deeper, membranous layer.
3) deep perineal fascia and muscles:

uperficial perineal pouch Contains superficial perineal muscles: transversus perinei superficialis, bulbospongiosus, ischiocavernosus
inferior fascia of urogenital diaphragm, or perineal membrane A membranous layer of the deep fascia.
deep perineal pouch Contains the deep perineal muscles: transversus perinei profundus, sphincter urethrae membranaceae
superior fascia of the urogenital diaphragm Considered hypothetical by some modern anatomists, but still commonly used to logically divide the contents of the region.

4) facia and muscles of pelvic floor (levator ani, coccygeus)


AREAS OF THE PERINEUM:

The region of the perineum can be considered a distinct area from pelvic cavity, with the two regions separated by the pelvic diaphragm. The following areas are thus classified as parts of the perineal region:
perineal pouches: superficial and deep (see above for details)
Ischioanal fossa - a fat filled space
Anal canal
Pudendal canal - contains internal pudendal artery and the pudendal nerve.

RIDING:

This area can become extremely sore among inexperienced bicyclists, horseback riders, motocross riders, and even ATV'ers

GLANS

The glans (Latin for "acorn", because the glans of an uncircumcised penis often looks like an acorn popping out of its cap) is a structure internally composed of corpus spongiosum in males or of corpus cavernosa and vestibular tissue in females that is located at the tip of homologous genital structures involved in sexual arousal.

STRUCTURE

The exterior structure of the glans consists of mucous membrane, which is usually covered by foreskin or clitoral hood in naturally developed genitalia. This covering, called the prepuce, is normally retractable in adulthood.

The glans naturally joins with the inner labia, and the frenulum of the penis or clitoris. In non-technical or sexual discussions, often the word "clitoris" refers to the external glans alone, excluding the clitoral hood, frenulum, and internal body of the clitoris.

GENDER DIFFERENCES

In males the glans is known as the glans penis, while in females the glans is known as the glans clitoris.

In females, the clitoris is above the urethra. This organ was once thought to serve no function other than sexual arousal, but research is beginning to prove otherwise. The glans of the clitoris is the most highly innervated part.

ABNORMAL DEVELOPMENT OF PENIS AND URETHRA:

If the fusion of the urethral folds fail to progress distally on the ventral penis, the urethra will be shortened. Hypospadias occurs when the fusion of the urethral folds stops proximal to the tip of the glans penis. The term, hypospadias, means under [hypo] the rent [spadon]. The rent refers to the appearance of the ventral glans penis. It appears to have been ripped (rent) apart. Hypospadias can occur anywhere along the urethral groove. In mild forms, the urethra opens just under the corona glandis. This is called coronal hypospadias.
When the internal urethral folds fail to fuse, causing hypospadias, the external urethral folds usually fail to fuse, causing a dorsal hood foreskin. Notice that the median raphé lies at an angle on the penile shaft.
Occasionally, the urethra develops only to the junction of the penis and scrotum. This boy has peno-scrotal hypospadias. As in this case, severe forms of hypospadias are accompanied by shortening of the urethral groove that causes ventral tethering of the penis. This condition, called chordee, can be severe enough to make sexual function impossible.

Whenever the foreskin appears shortened or abnormal on the ventral surface of the penis, one should suspect hypospadias. Occasionally, the external urethral folds develop and fuse despite failure of fusion of the internal urethral folds. In these boys, distal hypospadias occurs despite the presence of a complete prepuce. The urethral meatus must be examined before any circumcision is performed to make sure the boy does not have hypospadias.


Hypospadias occurs in about 1/125 infant males. In most cases, the cause of the hypospadias is not known. Certain conditions, however, are known to result in hypospadias. If the testes fail to produce adequate amounts of testosterone, virilization (enlargement and development of the genital tubercle and scrotal swellings) will not be complete and hypospadias will result. Similarly, if the cells of the genital structures lack adequate androgen receptors, hypospadias will occur. If those cells lack the androgen converting enzyme, 5 alpha reductase, inadequate androgen stimulation will follow and hypospadias will occur.

When severe forms of virilization failure occur (perineal hypospadias, or penoscrotal hypospadias with at least one undescended testicle) the infant must be evaluated for intersex (ambiguous genitalia). Intersex can be caused by hormonal abnormalities (congenital adrenal hyperplasia, ect.) and also by abnormal chromosomes (hermaphroditism, etc.).