Testicular descent and undescended testes

Abstract The postnatal physiology of the testis relies on a lower temperature for the testis to function optimally—this is deranged when the testis fails to reach the low-temperature environment of the scrotum, as with an undescended testis. Normal descent occurs as a two-step process: transabdominal and inguinoscrotal. The testes may continue to descend for 3 months post-term. Impalpable testes may be intra-canalicular or intra-abdominal—or absent. Palpable testes may be arrested in the line of normal descent or be ectopic. By 6 months of age, about 1–2% of boys have an undescended testis. An undescended testis cannot reside in the scrotum spontaneously. Orchidopexy should be performed by about 12 months of age to maximize the potential for normal fertility. The effect of timing of surgery in reducing the risk of malignancy is uncertain. Laparoscopy is performed for impalpable testes, with the subsequent procedure being determined by the laparoscopic findings.