Cryptorchidism in spina bifida and spinal cord transection: a clue to the mechanism of transinguinal descent of the testis.

In spina bifida there is a high incidence of cryptorchidism, particularly where the lesion is at or above L2. This article describes the location of the testis in 32 spina bifida patients and the effect of spinal cord transection in neonatal rats: both studies suggest that the spinal cord influences testicular descent. It is already established that androgens, an intact genitofemoral nerve, and the gubernaculum are essential for the transinguinal phase of testicular descent to occur. Yet the mechanism by which testosterone exerts its effect on the gubernaculum remains obscure. To account for all the observed phenomena we postulate that a spinal cord nucleus may exist that is sensitive to androgens and mediates impulses through the genitofemoral nerve to the gubernaculum. Neuronal modulation of the gubernaculum may induce testicular descent.