Uretero-Pelvic Junction Obstruction
A uretero-pelvic junction obstruction is a blockage of urine draining from the kidney at the point where the renal pelvis becomes the ureter. This is a congenital narrowing (present at birth) but can manifest at many ages in life. For many patients, a UPJ obstruction may never need treatment. UPJ obstructions that cause symptoms from blockage of urine flow (pain, infection, kidney stones, loss of kidney function) an excision of the obstructing segment and reconnection of the renal pelvis and ureter corrects the blockage. This surgery is called a Dismembered Pyeloplasty and is often done robotically.
A View of the UPJ on a CT scan
This video explains the UPJ obstruction viewing it from a CT scan. I narrate the CT images as they are displayed. A crossing arterial vessel is seen as a partial cause of the uretero-pelvic junction obstruction.