The testes are supplied by blood vessels that originate in the abdomen and course down through the inguinal canal as part of the spermatic cord to the testis.

The testis is drained by a plexus of veins called the pampiniform venous plexus. These course upward and coalescence to form the testicular vein. The left testicular vein drains at right angle into the left renal vein while the right testicular vein drains directly into the inferior vena cava.

Upward flow of blood in the veins is ensured by small one-way valves that prevent backflow.

A varicocele is an abnormal enlargement and tortuosity of the pampiniform plexus of veins (Fig. 25.1).

Varicoceles result from defective valves, or compression of the vein by a nearby structure. This leads to dilatation of the testicular veins and the formation of a varicocele.

The true incidence of adolescent varicoceles is not known because most adolescent varicoceles are asymptomatic.

The initial presentation of varicoceles usually occurs during puberty, with an incidence in 13-year-old adolescent boys equal to that of adult men (15 %).

Rarely, varicoceles are noted in the prepubertal period.

Although varicoceles may be bilateral, they are usually unilateral and almost always on the left side.

It has been estimated that 90 % of all varicoceles occur on the left side. This is attributed to the fact that the right testicular vein drain directly into the inferior vena cava while the left testicular vein drains at a right angle into the left renal vein. This predisposes to slower drainage in the left testicular vein.

A unilateral right-side varicocele raises certain concerns and should prompt an investigation for an underlying obstructive cause such as:

These patients should be investigated radiographically including computed tomography (CT).

Situs inversus is another rare cause of a right-side varicocele which must be kept in mind.

The exact etiology of varicoceles is unknown and various theories have been proposed to explain this taking in consideration the fact that 90 % of all varicoceles occur on the left side.

Varicoceles are divided into two types depending on the etiology.

Primary or idiopathic varicocele:

Secondary varicocele:

The pampiniform plexus of veins is the network of veins that normally drain the testicle.

Normally, the size of the veins that make up the pampiniform plexus range from 0.5 to 1.5 mm

This plexus of veins travels along the posterior portion of the testicle with the epididymis and vas deferens, and then into the spermatic cord and upwards where they coalesces to form the testicular vein.

Upward flow of blood in the veins is ensured by small one-way valves that prevent backflow.

The right testicular vein drains into the inferior vena cava, while the left testicular vein drains into the left renal vein at right angle to the renal vein, which then drains into the inferior vena cava.

The pampiniform plexus of veins not only drains the blood from the testes, vas and epididymis but also has an important function to lower the temperature of the testes.

A varicocele develops when there is dilatation and tortuosity of the veins of the pampiniform plexus.

It has been estimated that a varicocele develops when the size of these veins exceeds 2 mm.

The development of a varicocele with these dilated veins leads to an increase in the temperature around the testes resulting in testicular atrophy, reduction in the quality and the quantity of the sperms and infertility. This effect on sperm quantity and quality is progressive.

It has been shown also that blood from the testes that cannot drain via the pampiniform plexus may drain via communicating vessels through the prostate. The increased flow of blood to the prostate can lead to congestion and enlargement of the prostate gland secondary to cell proliferation resulting from the high concentration of free testosterone reaching directly from the testes to the prostate.

It has been shown that a varicocele that persists will lead to histopathological changes in the testis which include:

These changes may be reversed with corrective surgery.

The reasons for altered sperm production, testicular size, and morphologic changes in the testis are not clearly understood. The proposed pathophysiologic mechanisms include the followings: