Ureteropelvic junction obstruction (UPJO) is a specific type of ureteral stricture at the point where the ureter drains the urine from the renal pelvis. This can be a congenital abnormality (present since birth) or acquired (developed over time). Congenital UPJO may be detected in utero on prenatal ultrasound. In this case treatment is managed by a pediatric urologist. Not all congenital UPJO however is detected at birth and many are classically found during the teenage years when a patient of this age presents with recurrent flank pain. Still other cases may not be detected until later in adulthood. Acquired UPJO can have many causes including kidney stone disease or surgery of any type performed in the region of the ureteropelvic junction. UPJO can adversely affect the function of the kidney involved and most often should be repaired. The gold standard treatment for UPJO is pyeloplasty, a surgery that removes the affected segment of the renal pelvis and ureter and reconstructs the urinary drainage system. This can be performed through a robotic approach. See Robotic Upper Urinary Tract Reconstruction for more information.