Congenital Cryptorchidism: Spontaneously Descended Testes and Surgery at Different Ages Show Various Degrees of Impaired Testicular Growth at Puberty

Background This prospective randomized study concerns congenital unilaterally palpable undescended testes (UDT) from birth through puberty. At 6 months of age, boys were randomized to surgery and a testis biopsy at either 9 months or 3 years. Boys with congenital UDT with spontaneous descent after birth were followed as a separate cohort for comparison.Patients and methods Thirty-seven boys that were operated at 9 months and 48 at 3 years of age remained in the study at 16 years. All operated boys, and 22 boys with spontaneous descent between birth and 6 months were investigated with ultrasound to determine the testicular volume at ages 11 and 16 years. The degree of damage to the congenitally retained testes was expressed as the ratio between the initially retained testis and its scrotal counterpart.Findings At 16 years, the spontaneously descended testes showed a significantly lower ratio retained/scrotal volume but higher than the groups that underwent surgery. The initially retained testes in the surgically treated groups were still significantly smaller than their scrotal counterparts at both ages. The group that underwent surgery at 3 years showed a significant decrease in the ratio between 11 and 16 years, whereas the testes treated at 9 months showed no significant change.Interpretation The results show in accordance with our previously published volumetric and histological data that orchidopexy at 9 months, rather than at 3 years, results in better testicular growth at puberty. However, during the period of increase in spermatogenesis between 11 and 16 years, the originally retained testes do not show the same increase in testicular volume as their scrotal counterparts, which is also true for the testes that descended spontaneously before six months, although to a smaller degree.Funding: We acknowledge funding from the Stockholm City Council, Stiftelsen Frimurare Barnhuset, Sällskapet Barnavård and Karolinska InstitutetDeclaration of Interest: None to declare. Ethical Approval: This study was approved by the Swedish Ethical Review Board (Dnr: 96-198, 96-203 and 96-204). and carried out in accordance with the Declaration of Helsinki. The parents were informed that the age of any surgery had been randomised as part of this clinical trial and they all provided written, informed consent for their boys to be included in this study.