Undescended Testicle

An undescended testicle is a testicle which has not descended fully into the base of the scrotum by the time a baby boy is born.

Why does this condition occur?

The reason why a testicle may not fully descend is uncertain, however it may be due to a failure of chemical messages getting through to the testicle and associated structures at a critical time in the unborn baby's development. Another possibility is that the testicle itself has developed abnormally, and even though the chemical messages may be appropriate, the testicle and its associated structures are unable to respond appropriately to achieve complete descent.

How common is this condition?

Approximately 3% of baby boys are born with an undescended testicle. It is more common on the right side and may sometimes occur on both sides.

When can this be diagnosed?

At birth, or shortly after birth, the parents, doctors, or nurses will usually notice that either one or both testicles are not present in the scrotum. As the testicle originally develops at the level of the kidneys, it may be located anywhere between the kidneys and the top of the scrotum.

In the majority of cases, the undescended testicle is located in the inguinal region of the groin and is easily felt by a Paediatric Surgeon. Occasionally, the testicle may be found in the thigh adjacent to the scrotum, or even on the other side of the scrotum.

When a Paediatric Surgeon is unable to feel an undescended testicle, it is likely to be either located within the abdomen or to be completely absent. In this circumstance the testicle is called an 'impalpable testicle'. An ultrasound may sometimes be employed to locate the testicle, however, if the testicle is within the abdomen, an ultrasound is not particularly reliable.

If the testicle has undergone torsion (twist) either before birth or shortly after birth and has withered away to a small nubbin of tissue, it may also be 'impalpable'.

When To Operate?

As a large number of undescended testicles continue to descend until the age of 1 year, the Paediatric Surgeon will not suggest an operation prior to this time unless complications occur.

Approximately two thirds of undescended testicles first noticed at birth will descend into the base of the scrotum by 1 year of life. If the testicle remains undescended at 1 year, an orchidopexy will be recommended.

An orchidopexy is best performed by a Paediatric Surgeon and is an operation in which the undescended testicle is brought down to the base of the scrotum. For the health of the testicle, the operation should ideally be performed as soon after the first birthday as possible.

Why operate?

The undescended testicle is brought down into the scrotum to maximise fertility, to avoid the risk of trauma, or torsion (twist) and to achieve relative symmetry in the appearance of the scrotum.

Undescended testicles are at an increased risk of developing cancer. This risk is approximately 1 in 40,000, and if it occurs it usually occurs between the ages of 12 and 35 years. It is of course more easily and earlier detected if the testicle is located in its normal position within the scrotum.

As most undescended testicles have the potential to also develop an inguinal hernia, parents should be made aware of this possibility. If an inguinal hernia was to develop in the first year of life, it would need to be repaired urgently, and the undescended testicle may in some circumstances be brought down into the scrotum at the same time.

When is a two stage operation appropriate?

In particularly high undescended testicles, or in the testicles that are located within the abdomen, the operation to bring the testicle down to the scrotum may need to be done in two stages.

What are the long term results?

After the testicle has been brought down in to the scrotum, the prognosis is excellent in the majority of cases.

Fertility in these boys is no different from that of the general male population, however, if there has been undescended testicles on both sides, fertility is reduced by about 30%.

Fertility in both single and double undescended testicles may also be further reduced if the operation is delayed beyond 2 years of life.