Objective: To investigate whether in congenital unilateral cryptorchidism the growth of a spontaneously descended testis is normal, compared with the contralateral scrotal testis or similar to the growth of testes that failed to descend spontaneously and later underwent orchidopexy.
Methods: Ninety-one boys with congenital unilateral cryptorchidism with later spontaneous descent of the initially retained testis were followed from birth (0-3 weeks) up to 5 years of age and compared with boys randomized to surgery at either 9 months (n = 78) or 3 years (n = 85) of age. Testicular volume was determined with ultrasonography.
Results: Eighty-two percent of spontaneous descent occurred before 2 months of age. Twenty-two percent of these descended testes were later again found in a retained position. The spontaneously descended testis was smaller than its scrotal counterpart at all ages (P < .001). We also showed a significant difference in the testicular volume between the early and late treated boys from age 2 years and onward. At 2, 4, and 5 years of age, the volumes of the spontaneously descended testes were significantly larger than those of boys operated on at 3 years but similar to those operated on at 9 months.
Conclusions: We have shown that in boys with congenital unilateral cryptorchidism with later spontaneous descent, the originally retained testes show impaired growth compared with its scrotal counterpart from birth and onwards. Also, they are prone to later ascent to a retained position. Furthermore, the longer testes remain untreated the more they exhibit impaired growth.