What are the most common and clinically important complications of percutaneous nephrolithotomy (PCNL)?

Complications of Percutaneous Nephrolithotomy (PCNL)

PCNL carries an overall complication rate of approximately 10-15%, with hemorrhage requiring transfusion (15%), infectious complications including septic shock (4% overall, 10% in pyonephrosis), and pleural injuries (15%) being the most clinically significant complications that impact morbidity and mortality. 1, 2, 3

Major Hemorrhagic Complications

Bleeding is the most common serious complication requiring intervention:

• Mild hematuria occurs in approximately 50% of patients and is considered an expected finding that does not require intervention 1, 2
• Clinically significant bleeding requiring blood transfusion occurs in 15% of PCNL cases, which is substantially higher than the 4% threshold for simple percutaneous nephrostomy 1, 2, 4
• Thrombocytopenia is a key risk factor that significantly increases bleeding risk and should be corrected preoperatively 1, 2

Management of persistent bleeding:

• Persistent postoperative bleeding mandates arteriographic evaluation to identify pseudoaneurysm, arteriovenous fistula, or active extravasation 1, 2
• Transcatheter embolization is the definitive treatment for vascular injuries, with the threshold for requiring embolization or nephrectomy set at 1% 1

Infectious Complications

Sepsis represents the most life-threatening complication:

• Septic shock develops in 4% of all PCNL cases and escalates to 10% in patients with pyonephrosis 1, 2, 3
• Fever occurs in 10.8% of cases and may represent the early warning sign of developing sepsis 3

Critical risk factors for infectious complications include:

• Positive urine culture (OR = 3.16), positive renal pelvis urine culture (OR = 5.81), and positive stone culture (OR = 5.11) 5
• Infected stones (OR = 7.00), elevated neutrophil-to-lymphocyte ratio, and positive urine leukocytes (OR = 3.61) 5
• Multiple puncture access (OR = 2.58) and prolonged operative time 5

Absolute contraindication: If purulent urine is encountered during the procedure, abort immediately and establish drainage with nephrostomy or ureteral stent while continuing broad-spectrum antibiotics 2

Pleural and Thoracic Complications

Supracostal access carries substantially higher risk:

• Pleural complications (pneumothorax, empyema, hemothorax) occur in 15% of PCNL procedures overall, compared to only 1% for simple percutaneous nephrostomy 1, 4
• Upper-pole calyceal puncture significantly increases pneumothorax risk, though intercostal approach may be necessary for optimal stone access 1
• Overall thoracic complications occur in 1.5% of cases 3

Visceral Organ Injuries

Rare but serious injuries to adjacent structures:

• Bowel injury occurs in <1% of cases and requires immediate surgical consultation 1, 3
• Splenic injury, gallbladder puncture, and other organ injuries are uncommon but must be identified on preoperative imaging 1, 3
• Preoperative ultrasound or CT is mandatory to identify interposed organs (liver, spleen, bowel) and plan safe access routes 3

Tube-Related Complications

Mechanical issues with drainage catheters:

• Nephrostomy tubes are prone to fracture, dislodgement, and occlusion 1, 2
• Catheter displacement is one of the most common adverse events requiring intervention 1

Other Significant Complications

Additional complications with established thresholds:

• Urinoma formation occurs in 0.2% of cases 3
• Thromboembolic complications can occur, particularly in prolonged procedures 6, 7
• Mortality rate is 0.05%, representing the ultimate measure of procedural risk 3

Risk Stratification and Prevention

Preoperative factors that increase overall complication risk:

• Stone burden, operative time, and patient comorbidities are primary risk factors 3
• Female gender (OR = 1.60), preoperative stenting (OR = 1.55), and postoperative residual stones (OR = 1.56) increase infection risk 5
• Patients on anticoagulants require careful monitoring and medication adjustment before proceeding 3

Critical Pitfalls to Avoid

Common errors that increase complication rates:

• Proceeding with active infection: Always establish drainage and control infection before stone fragmentation 2
• Using non-isotonic irrigation solutions: Normal saline is mandatory to prevent hemolysis, hyponatremia, and cardiac complications 2, 3
• Inadequate preoperative imaging: Failure to identify interposed organs increases visceral injury risk 3
• Not performing flexible nephroscopy: This increases residual stone rates and need for secondary procedures 2, 3