What is the maximum size of a common bile duct (CBD) stone that can be extracted by endoscopic retrograde cholangiopancreatography (ERCP)?

Maximum Size of CBD Stone Extractable by ERCP

Standard ERCP with sphincterotomy and balloon/basket extraction can successfully remove CBD stones up to approximately 15 mm in diameter, with success rates declining dramatically for stones larger than this threshold. 1

Stone Size and Extraction Success Rates

Standard Extraction Techniques

• Stones <10 mm: Nearly 100% successful extraction with standard ERCP techniques (sphincterotomy with balloon catheter or Dormia basket). 1
• Stones 10-15 mm: Moderate success rates, often requiring mechanical lithotripsy as the next-line approach. 2
• Stones >15 mm: Only 12% success rate with standard extraction techniques alone, requiring advanced interventions. 1
• Stones up to 25 mm: Can be managed with mechanical lithotripsy when standard extraction fails. 2

Advanced Techniques for Larger Stones

For stones 15-25 mm, mechanical lithotripsy is the method of choice as the next step after failed standard extraction. 2 Endoscopic papillary large balloon dilation (EPLBD) has become the gold standard for large CBD stones up to 15 mm, reducing procedural time and device costs. 3

For stones >25 mm or very large/impacted stones, additional advanced lithotripsy techniques are required:

• Laser lithotripsy shows the best results for CBD stones with 80-95% success rates. 2
• Electrohydraulic lithotripsy (EHL) achieves similar 80-95% success rates but has higher tissue damage risk. 2
• Peroral cholangioscopy with probe-based lithotripsy (electrohydraulic or laser) provides direct visualization for very large stones. 3

Clinical Management Algorithm

Initial Approach

Stones ≤15 mm: Proceed with standard ERCP, sphincterotomy, and balloon/basket extraction. 4, 1 Success is highly likely, with stones <10 mm having near-universal clearance rates. 1

Escalation for Difficult Stones

Stones 15-25 mm: Use EPLBD with prior sphincterotomy and mechanical lithotripsy. 4, 3 This combination is highly successful and cost-effective compared to multiple extraction attempts. 3

Stones >25 mm or impacted stones: Require cholangioscopy-directed lithotripsy (laser or electrohydraulic) or extracorporeal shock wave lithotripsy (ESWL) when available. 4, 2 These techniques achieve 80-95% success rates for very large stones. 2

Important Caveats

Stone Size Measurement

Stone size should be measured on MRCP or ERCP cholangiograms with correction for magnification. 1 MRCP has diminishing sensitivity for stones <4 mm, which may spontaneously pass. 4, 5

Temporary Management

When immediate extraction fails, biliary stenting can reduce stone size over time (mean reduction from 24.9 mm to 20.1 mm after median 63 days), potentially facilitating subsequent removal. 6 However, stenting as definitive treatment should be restricted to patients with limited life expectancy or prohibitive surgical risk. 4

Alternative Approaches

For stones that cannot be removed despite advanced endoscopic techniques (EPLBD, mechanical lithotripsy, cholangioscopy), percutaneous radiological extraction or open duct exploration should be considered. 4 Laparoscopic bile duct exploration is also highly effective and can achieve near 100% clearance with intraductal lithotripsy. 4

Technical Limitations

The number of stones does not significantly affect success rates, but stone size is the critical determinant of extraction difficulty. 1 Stones in patients with altered anatomy from previous surgery may require alternative approaches regardless of size. 4