Pathophysiology of UPJ obstruction - Current concepts

Congenital hydronephrosis caused by ureteropelvic junction (UPJ) obstruction has challenged the ingenuity of urologic surgeons and remains one of the most enigmatic clinical problems today. In a practical sense, UPJ obstruction may be defined as a functional or anatomic obstruction to urine flow from the renal pelvis to the ureter that left untreated results in symptoms or renal damage. This article explores the embryologic aspects of renal and ureteral development, the types of UPJ obstruction (anatomic classification), vesicoureteral reflux, renal mobility, and clinical observations.