Fetal surgery for obstructive uropathy: rational considerations.

The widespread use of high resolution dynamic ultrasound imaging methods in obstetrics now permits recognition of structural and/or functional developmental anomalies of fetal genitourinary tract with some considerable accuracy. Detection of congenital obstructive uropathy in the human fetus may occur as early as 16 weeks gestation. In the fetal lamb model, experimental occlusion of the outflow tract results in progressive hydronephrosis, pulmonary hypoplasia, and oligohydramnios. The renal parenchymal changes vary with the fetal age at obstruction ranging from simple hydronephrosis with later obstruction to dysgenesis with earlier obstruction. The pulmonary damage, and to some extent the renal damage, may be halted or even reversed with release of obstruction. These advances in diagnosis and an understanding of the pathophysiology have prompted attempts at chronic in utero diversion therapy in the human fetus with obstructive uropathy yielding encouraging, but as of yet, unproven success. In this report, the methods for such therapy, the rationale for the therapy, and the results of the therapy is reviewed.