What are the adverse effects of Extracorporeal Shock Wave Lithotripsy (ESWL) and how are they managed?

Adverse Effects of ESWL: Incidence and Management

ESWL has fewer complications than percutaneous nephrolithotomy or ureteroscopy, with most adverse effects being mild (Clavien grade I-II in 18.43% of cases) and managed conservatively, though serious complications (Clavien grade III-IV) occur in 2.48% of patients. 1

Classification of Adverse Effects by Severity

Minor Complications (Clavien Grade I-II)

Stone Fragment-Related Complications:

• Colicky pain occurs in approximately 40% of patients and represents the most frequent complication 2
• Macroscopic hematuria develops in 17.2% of cases 1
• Steinstrasse (stone street formation) occurs in 4-24.2% of patients 1, 2
• Renal colic affects 2-4% of patients 1
• Residual fragment regrowth occurs in 21-59% of cases 1

Management of Minor Complications:

• Most minor complications resolve with conservative management or minimal intervention 2
• Medical expulsive therapy (MET), mechanical percussion, and diuretics can enhance stone passage and reduce analgesic needs 1
• Routine pre-stenting before ESWL does not improve stone-free rates but may reduce steinstrasse formation 1

Infectious Complications

Incidence:

• Bacteriuria develops in 7.7-23% of patients with non-infected stones 1
• Symptomatic bacteriuria occurs in 9.7% of patients, with Escherichia coli being the most common causative organism (30.4%) 2
• Sepsis is rare at 0.15% 1

Management:

• Perioperative antibiotic prophylaxis should be offered to all patients undergoing ESWL 1
• The choice of antibiotic prophylaxis should be tailored to institutional or regional antimicrobial susceptibility patterns 1

Tissue-Related Complications

Renal Complications:

• Asymptomatic hematoma occurs in 1.2% of cases 1
• Symptomatic hematoma develops in 0.21% of patients 1
• A decline in kidney function has been reported in small case series, particularly in children with primary hyperoxaluria, though this may reflect the natural disease course rather than ESWL-specific injury 1

Cardiovascular Complications:

• Cardiac dysrhythmias occur in 11-29% of patients 1
• In patients with pacemakers or defibrillators, ESWL is feasible with technical precautions; newer lithotripters may eliminate the need for reprogramming 1

Major Complications (Clavien Grade III-IV)

• Auxiliary procedures are required in 6-9% of cases 1
• Serious complications (Clavien grade III-IV) occur in 2.48% of patients 1

Long-Term Concerns

Hypertension and Diabetes:

• The link between ESWL and hypertension/diabetes remains unclear, with no conclusive evidence of long-term adverse effects 1, 3
• Current evidence does not support withholding ESWL based on diabetes concerns alone 3

Risk Mitigation Strategies

Technical Optimization:

• Decreasing shockwave frequency from 120 to 60-90 shockwaves per minute improves stone-free rates and reduces tissue damage 1
• Stepwise energy ramping minimizes renal injury 1
• Proper acoustic coupling between the treatment head and skin is crucial, as air pockets can deflect shockwaves 1
• Operator experience significantly impacts outcomes; better results are observed when ESWL is performed by experienced clinicians with precise imaging control 1

Special Populations and Contraindications

Absolute Contraindications:

• Pregnancy 1
• Bleeding disorders 1
• Uncontrolled urinary tract infection 1
• Arterial aneurysm near the stone 1
• Anatomic obstructions distal to the stone 1

High-Risk Bleeding Procedures:

• ESWL is classified as a procedure with high bleeding risk 1
• Patients with bleeding disorders or receiving antithrombotic therapy should be referred to an internist for appropriate therapeutic measures before proceeding 1

Critical Pitfalls to Avoid

• Avoid dehydration in the perioperative period, particularly in patients with primary hyperoxaluria, as even mild dehydration can lead to acute kidney injury 1
• Do not perform routine post-procedure stenting after uncomplicated ESWL, as this may increase morbidity without improving outcomes 1
• Recognize that ESWL has inferior outcomes compared to percutaneous nephrolithotomy for complex stones, particularly in primary hyperoxaluria patients where stone-free rates may be as low as 20-47% 1