51 - Undescended testes

Summary

Since ancient times, it has been recognized that the testis needs to be fully descended in the scrotum for normal functioning. Indeed, the testis derives its name from the Latin word “witness,” following the custom in Roman times to hold the testicles when taking an oath. Hence, one of the primary concerns of surgeons has been the development of surgical procedures to place an undescended testis into the scrotum. In recent years there have been rapid changes in attitudes to long-term outcomes: not that long ago, success of surgery was measured by such crude criteria as cosmetic result or survival, which could be determined immediately. However, now the profession and the community require and expect a much higher standard, such that at present the yardstick for success in the management of undescended testes is normal fertility and a low risk of malignancy in adult life. Community attitudes, and knowledge about long-term outcomes, are changing rapidly, as evidenced by the fact that standard texts only 25 years ago did not contain any significant information about long-term malignancy risks.

Etiology of the undescended testis

Most undescended testes are probably caused by abnormal migration of the gubernaculum during the inguinoscrotal phase of testicular descent. Testicular descent normally begins at about 10 weeks of gestation, shortly after the onset of sexual differentiation. Two morphological steps in descent can be identified: initial relative movement of the testis (compared with the ovary) from the urogenital ridge to the inguinal region, known as transabdominal descent; and migration from the inguinal canal to the scrotum, known as inguinoscrotal descent.