The testicle (testis) is responsible for the production of male hormone and also sperm. Before the child is born the testicle migrates down from high in the abdomen and passes through abdominal wall and groin to take its normal position in the scrotum. Undescended testicles are quite common. They may be present in 4% of boys at birth, and there is an even higher incidence in premature infants. Three-fourths of undescended testicles will descend within the first three months of life.
When a testicle is not in the normal scrotal location several possibilities exist:
- There may never have been a testicle (congenital absence).
- The testicle may have atrophied (withered away) before birth due to torsion (twist) or blockage of the testicular blood vessels.
- The testicle may have descended incompletely and may lie within the inguinal canal (just above the scrotum).
- The testicle may have not descended properly, but remains within the abdominal cavity.
- In some children the testes may be found in the groin, but can be brought down into the scrotum during examination. These ‘retractile’ testicles also will be seen to descend when the child is in the bathtub. Retractile testicles are due to hyperactive muscles that temporarily pull the testicle into the groin. However, retractile testicles are not believed to injure the testicles and require no treatment.
Why should an undescended testicle be treated?
In humans, the scrotal location of the testicles keeps them cooler than the core body temperature. This lower temperature is important for the development of the testicle as well as for production of normal sperm. Relocating the testicle into the scrotum may decrease the risk of fertility problems, particularly if done at an early age.
There are other advantages to a location within the scrotum. There is a cosmetic advantage. The scrotal testicle may be less amenable to injury than a testicle outside the scrotum. Finally, and perhaps as important as any other reason, a testicle that has not made it into the scrotum is not accessible to physical examination. Undescended testicles are at increased risk for cancer. Testicular cancer may not occur until after age 40 years. Testicular carcinoma is highly curable, when detected early, and the best way to do this is monthly self-examination, which can only be done if the testicles are within the scrotum.
Treatment for undescended testicle
We recommend treatment of the undescended testicle before one year of age. There is evidence that early damage to the germ cells that produce sperm begins at this age. There are two options for treatment. Injections of a hormone, HCG, several times per week over several weeks can produce descent in some children. However, the success rates have been reported to be as low as 10%. Also, the results of hormone treatment are less successful in children less than two years of age.
The most effective treatment is surgery, which can be performed as an outpatient. When a testis is felt in the groin area we usually explore the area through a small incision. Most undescended testes are associated with a hernia that must be repaired. After this is done, the testis is brought down into the scrotum and anchored in a space created in the scrotum (orchiopexy).
When a testis is not palpable on physical exam, its location must be determined. We have not found x-rays to be reliable in this regard. We place a laparoscope through a small incision below the ‘belly button’ to look in the abdomen at the time of surgery. In those patients found to have testes very high in the abdomen, additional surgery is required to correct the problem. A number of children will be found to have very small abnormal gonads which we will remove (orchiectomy). Most of these children probably had torsion or twisting of the testis on its blood supply prior to birth that led to the small testis. When a boy is left with a single functioning testis we recommend anchoring it to minimize chances of losing it to torsion later in life.