Percutaneous nephrostomy is a well-established urological procedure used to relieve pressure on the kidney in cases of impaired urine flow. During a nephrostomy, a catheter is inserted into the renal pelvis via a puncture so that urine can flow freely again. Percutaneous nephrostomy is used in particular for urinary tract obstruction or hydronephrosis. The procedure is usually performed under imaging guidance and allows for rapid urine drainage. Causes may include tumors, kidney stones, or narrowing of the ureter. Percutaneous nephrostomy may become necessary on an emergency basis to preserve kidney function. Despite a high success rate, potential risks and complications should be taken into account.
Indications for Percutaneous Nephrostomy
The placement of a percutaneous nephrostomy is indicated for short-term urinary drainage in cases of
- obstruction of a kidney or
- a urinary fistula following ureteral injury
.
Causes of obstructed renal drainage include
- obstructive ureteral stones,
- tumors,
- fibrosis (scarring),
- inflammation, and
- injuries.
There are no absolute contraindications to percutaneous nephrostomy—that is, situations in which the procedure cannot be performed. Coagulation disorders are considered relative contraindications. However, in patients with urosepsis and consequent disseminated coagulopathy, PCN can be life-saving.
Advantages of percutaneous nephrostomy
- Quick to perform
- minimal preparation required
- Local anesthesia, thus no general anesthesia
- Safe procedure with a low complication rate
- Ultrasound is the only imaging modality required
- PCN is the basis for minimally invasive procedures on the renal pelvis
Technique of Percutaneous Nephrostomy
The kidney is punctured into a renal calyx. During the procedure, the surgeon guides the instruments using ultrasound or X-ray imaging. If the puncture is successful, the surgeon inserts a plastic tube through the renal calyx into the renal pelvis.
The urine then drains through the drainage catheter, which is secured to the skin, and is collected in a urine bag.
In a percutaneous nephrostomy, catheters drain urine directly from the kidneys © peterschreiber.media | AdobeStock
The procedure is performed in the following steps:
- The patient is positioned on their side
- Sterile draping
- Ultrasound imaging of the distended kidney using a sterile puncture transducer in the axillary line
- Determination of the puncture site, direction, and depth
- Local infiltration of the skin with a local anesthetic
- Incision of the skin
- Puncture of the hydronephrotic kidney under continuous ultrasound guidance
- The needle-tip reflex is visible in the distended renal pelvis
- Aspiration of urine
- Advancing the semi-rigid guidewire through the puncture needle
- The wire can be visualized by ultrasound within the renal pelvis
- Withdrawal of the puncture needle
- The pigtail catheter is now advanced into the renal pelvis over the guidewire
- Repeat aspiration of urine
- Secure the catheter to the skin with a suture
- Dressing
The catheter is replaced using a guidewire under X-ray guidance.
The replacement intervals vary depending on the patient. The PCN should not be replaced routinely at fixed intervals, but rather as needed based on individual factors. These factors include
- urine output,
- contamination,
- propensity for encrustation, and
- infections.
FAQ
What is a percutaneous nephrostomy?
Percutaneous nephrostomy is a procedure for urine drainage in which a nephrostomy catheter is inserted through the skin directly into the renal pelvis. Urine is drained through a catheter into a urine bag. The procedure is also known as PCN or percutaneous nephrostomy.
When is a nephrostomy necessary?
A nephrostomy is indicated in cases of urinary stasis, hydronephrosis, acute obstruction, or chronic obstruction of the urinary tract. Common causes include tumors, kidney stones, ureteral strictures, or an infected hydronephrotic kidney. Failure of retrograde catheterization may also be an indication.
How is a nephrostomy performed?
The procedure is usually performed with the patient in the prone or lateral position under local anesthesia or general anesthesia. A group of renal calyces is punctured using a hollow needle under ultrasound guidance or fluoroscopy. The nephrostomy catheter is then advanced into the renal pelvis via a guidewire and secured to the skin.
What are the risks and complications?
Risks and complications include bleeding, infection, catheter obstruction, or injury to adjacent structures such as the intestine or colon. In rare cases, urosepsis may occur. Pre-existing coagulation disorders are considered a major contraindication.
How long does a nephrostomy catheter remain in place?
The duration depends on the cause of the urinary obstruction and the condition of the urinary tract. The catheter may be needed temporarily or long-term. Regular follow-up visits with a urologist are important to monitor the ureters, bladder, and kidney function.
