ABSTRACT
Ureteropelvic junction obstruction (UPJO) is the most common congenital condition affecting the kidney with an incidence of approximately one in 400 live births. Indications for surgical treatment may include presence of pain, pyelonephritis, secondary renal stones, and decreased renal function. Preoperative studies should include a diuretic renal scan for determination of differential renal function and severity of obstruction as well as an anatomic study such as an excretory urogram or retrograde pyelogram in order to evaluate for coexisting ureteral pathology and optimally define the UPJ anatomy. Computed tomography (CT) can be additionally helpful for identifying renal calculi as well as lower pole crossing vessels.
