One can consider percutaneous nephrostomy and ureteral stenting as belonging under this topic or under topic A16.

Percutaneous nephrostomy

Percutaneous nephrostomy (PCN) refers to creating an opening through the skin into the renal pelvis, allowing urine to drain directly from the pelvis into a urinary collection bag. The procedure is guided by ultrasound. In case of hydronephrosis with pyelonephritis, PCN must be performed emergently to allow drainage of the infected urine. The most common indication for PCN is a need for urinary drainage which cannot be achieved otherwise.

Indications
- Complete urinary tract obstruction causing hydronephrosis
- Hydronephrosis with pyelonephritis (also called obstructive pyelonephritis or pyonephrosis)
- Allowing the ureter to heal in case of injury or severe haemorrhagic cystitis
Procedure
- A needle is advanced through the flank into the collecting system
- Urine is aspirated
- A guidewire is inserted through the needle
- The needle is removed
- The lumen is enlarged by passing dilators over the guidewire
- Once the lumen is large enough a pigtail catheter is placed

Percutaneous nephrolithotomy

Percutaneous nephrolithotomy is a procedure for treating kidney stones where a percutaneous nephrostomy is created and instruments are led through the opening and into the renal pelvis. These instruments allow for collection, vaporisation (with laser) or crushing of the stone.

Indications:

Stones which cannot be removed by other measures
Pregnant people with kidney stone that must be removed
Staghorn calculi

Ureteral stent

A ureteral stent is a small tube which is inserted into the ureter to keep them open. Urine can flow through this tube and bypass any obstruction. They are also called double J stents due to the ends of the stents being J-shaped and are therefore sometimes called JJ or DJ stents.

Ureteral stenting is usually performed retrograde from the bladder by cystoscopy. Once in the bladder, the ureteral orifice is cannulated and the stent is inserted. It can also be performed anterograde through a nephrostomy, but this is not the first choice. Antibiotic prophylaxis is recommended in either case.

The stent is replaced or removed after a few weeks or months. JJ stents are often a preferred alternative to a percutaneous nephrostomy.

Indications

Urinary tract obstruction at the level of the ureter - due to ureter stone, tumour, retroperitoneal fibrosis
Ureteral surgery or injury to the ureter - to allow proper healing

Transcatheter embolisation

In urology, transcatheter embolisation is used on the following indications:

To embolise arteriovenous fistulas and arteriovenous malformations in the renal arteries
Stop severe bleeding from the urinary system, for example from the kidney, bladder, or pelvis
Pre- or postoperatively for renal cell carcinoma in very large or highly vascularised tumours
To induce renal infarction and thereby reducing kidney function, in case of severe nephrotic syndrome or in case of end-stage kidney failure and hypertension
To treat a primary varicocoele

Renal artery angioplasty and stenting

Renal artery stenosis refers to a narrowing of a renal artery. It may be bilateral in rare cases. It's most commonly due to atherosclerosis (in elderly) and fibromuscular dysplasia (in young). It may lead to secondary hypertension and chronic kidney disease.

Management

Renal artery stenosis is managed by balloon dilatation and stenting of the stenosis. The interventional radiologist inserts a wire into the femoral artery and leads it to the renal artery. A balloon is inflated at the stenosis, after which a stent is placed.