Percutaneous Nephrostomy

Background and indications

Percutaneous nephrostomy involves inserting a drain through the skin and renal parenchyma into the pyelocaliceal system (renal pelvis), enabling external urine drainage. It is indicated for ureteral obstruction with hydronephrosis (obstructive stone, pelvic tumor compressing ureter, ureteral stenosis), obstructive renal failure (bilateral or solitary kidney), pyonephrosis (infection with obstruction), and as access for endourological procedures (percutaneous lithotripsy).

Pre-procedure assessment

Assessment includes abdomino-pelvic CT (obstruction cause and level, hydronephrosis degree), renal function panel (creatinine, GFR), urine culture (urinary tract infection), and coagulation panel. In emergencies (pyonephrosis, acute renal failure), drainage is performed promptly after minimal workup.

Procedure

Under local anesthesia and sedation, in prone or lateral position, a posterior-inferior calyx is punctured under ultrasound and fluoroscopic guidance. A guidewire is advanced into the renal pelvis and a pigtail drain (8-12F) is placed and secured to skin. Urine is analyzed (bacteriology). For pyonephrosis, purulent urine is drained and IV antibiotic therapy is started. The procedure takes 20-40 minutes.

Results and scientific evidence

Technical success rate is 95-99%. Nephrostomy enables rapid renal function improvement in bilateral obstruction (creatinine normalization in 3-7 days in most cases). For obstructive stones, nephrostomy decompresses the kidney pending lithotripsy. Percutaneous nephrostomy is the EAU-recommended standard of care for emergency decompression of an infected obstructive kidney.

Risks and complications

Hemorrhage (transient hematuria: 10-20%, transfusion-requiring hemorrhage: 1-3%), infection/sepsis (2-5%), drain displacement (5-10%), adjacent organ injury (colon: < 0.5%, pleura: < 1%). Procedural mortality is < 0.5%.

Recovery

1-3 day hospitalization. Drain maintained until definitive obstruction treatment (JJ stent, lithotripsy, surgery). For palliative tumor obstructions, drain may be maintained long-term (changed every 2-3 months).

Practical information

The procedure is performed as an inpatient or outpatient depending on context. It is performed by an interventional radiologist, in coordination with the urologist and nephrologist.