At the junction of the renal pelvis (where urine is collected after being produced by the kidney) and the ureter (the connecting tube between kidney and bladder) there can be a blockage. This is called a PUJ (pelviureteric junction) obstruction. It may be attributed to functional or anatomical abnormalities, or there may even be an association between them. Additionally, secondary PUJ obstructions may occur after endoscopic or open urinary tract procedures.
Congenital PUJ obstruction is quite common. It can present in the newborn as a mass and in the adult with flank pain on hydration, the so-called beer drinker’s kidney. There are often associated gastrointestinal symptoms such as nausea and vomiting. Diagnosis is established by ultrasound or CT scan showing a dilated renal pelvis with a normal sized ureter. Excretory urography with delayed films or a diuretic renogram (DTPA or MAG 3 scan) noting impairment of renal excretion of contrast or radionuclide material is often performed to confirm the diagnosis.
The treatment of PUJ obstruction is normally through a surgical procedure called dismembered pyeloplasty. In this procedure the narrowed PUJ segment is excised and the normal renal pelvis is joined to the normal ureter. This can be done as an open operation or more commonly nowadays as a minimally invasive laparoscopic or da Vinci robotic pyeloplasty. The minimally invasive approach offers smaller incisions, less scaring, less pain, faster recovery and return to normal duties. A ureteric stent is inserted at the end of the operation ad removed at a later stage.If the kidney has minimal function (typically <10%), a nephrectomy rather than a pyeloplasty is performed.