Percutaneous puncture nephrostomy

Indications and patient preparation

Nephrostomy placement must not be delayed if pyonephrosis or infected hydronephrosis is suspected. Other classic indications include:

• Urinary tract obstruction of any etiology (calculi, tumors, iatrogenic strictures, retroperitoneal fibrosis).
• Urinary leakage (urinary leakage) or fistula formation.
• Urinary diversion in severe hemorrhagic cystitis.
• Creation of access for percutaneous nephrolithotomy (PCNL), stenting, or biopsy.

The procedure requires written informed consent and adequate hydration. Coagulation profile monitoring is mandatory. Antibiotic prophylaxis is administered to all patients: a single dose for the low-risk group or prolonged therapy for elderly patients, those with diabetes, and patients with indwelling catheters. There are absolute contraindications to the procedure; severe coagulopathy is a relative contraindication requiring prior correction.

Anatomical landmarks and choice of access

The classic patient position is prone (prone). Access safety directly depends on the knowledge of topographic anatomy:

• Calyces (calyces) are directed anteriorly or posteriorly. The posterior calyces are located more superficially and medially.
• Renal axis is directed posterolaterally, with the upper pole lying more posteriorly.
• Pleura descends to the 12th rib; therefore, punctures above this level must be performed laterally to avoid pneumothorax or empyema.

Posterolateral puncture of the lower pole calyx center is recognized as the safest route. Access through the upper pole provides a more convenient navigation vector, but carries a high risk of pleural, hepatic, or splenic injury (especially with an overly lateral puncture). Intercostal arteries always run along the inferior margin of the rib, dictating the rule to puncture above the upper margin.

Instrumentation: systems, guidewires, and catheters

Single-component systems (18-G needle with a 4-F introducer) or two-component systems (21-G needle) are used for initial access.

Guidewires (guidewires): The ideal guidewire for initial navigation in a narrow calyx should be soft with good torque control (torque), such as a straight Bentsen or a hydrophilic guidewire with an angled tip. For subsequent manipulations (tract dilation), stiff guidewires such as Amplatz or hydrophilic guidewires with a stiff core are required. The standard size is 0.035 inches.

Catheters (catheters): A pigtail catheter with a diameter of > 6 F is optimal for drainage. Large side-holes on its inner curve prevent obstruction when the renal pelvis collapses. Short catheters with high trackability (e.g., Kumpe or Cobra) are used for navigation.

Navigation methods

The choice of imaging method depends on the degree of pelvicalyceal system (PCS) dilation:

1. Ultrasound guidance: Routine method for a dilated PCS. Allows safe puncture of the posterior calyces.
2. Fluoroscopy: Used with intravenous administration of iodinated contrast. Since posterior calyces fill worst with contrast in the prone position, a double-contrast pyelography technique is used—slow administration of gas (no more than 20 mL), which rises into the non-dependent posterior regions.
3. CT guidance: The method of choice for complex anatomy (horseshoe or dystopic kidney, risk of retrorenal colon position).

In difficult situations, combined ultrasound and fluoroscopic guidance with a double puncture is often used: the first needle (22-G) is introduced under ultrasound for contrast opacification, and the second is targeted into the target calyx under fluoroscopy.

Complications and drainage fixation

The rate of severe complications is low, but they require immediate response. Septic shock occurs in 4% of cases (up to 10% in pyonephrosis). To prevent this, overdistension of the PCS with contrast during puncture must be avoided. Bleeding requiring blood transfusion occurs in 4% of cases. Venous hemorrhages are controlled by catheter tamponade, while arterial ones may require angiography with embolization.

Fixation: Internal fixation of the pigtail catheter using a locking suture is insufficient. An interrupted suture is placed on the skin, and the suture is wrapped around the tube in a "Roman sandal" (Roman sandal) configuration. When removing the catheter, it is important to unlock the suture first; cutting the catheter near the hub is strictly discouraged due to the risk of leaving a foreign body behind.

Briefly: answers to topical questions

Class and exam questions

What else to study on this topic

• Features of access in a transplanted kidney
• Gas double-contrast technique in a non-dilated PCS
• Patient management strategy in iatrogenic bowel injury
• Pediatric nephrostomy: managing rapid system decompression
• Detailed analysis of guidewire types in endourology

Other topics in the "Interventional radiology" section

Prepared by WhiteCoat Pro faculty in accordance with the medical school curriculum. For educational purposes only.