Randomized Trial for Extraction of Large Bile Duct Stones

Stones in the bile duct can result in various complications including acute cholangitis,
acute pancreatitis and secondary biliary cirrhosis.1 Bile duct stones should therefore be
removed and this can be successfully achieved in 85-90% of patients using standard endoscopic
techniques. This comprises endoscopic sphincterotomy whereby the duodenal sphincter at the
entrance of the bile duct is cut during endoscopic retrograde cholangiopancreatography (ERCP)
and subsequent removal of the stone is achieved using standard accessories such as a basket
and/or extraction balloon.2 However, large (≥ 15mm in size) or multiple stones and those
located in non-dilated bile ducts can be difficult to remove by endoscopic sphincterotomy and
using only standard accessories.2 In such cases, mechanical lithotripsy can be performed for
stone fragmentation prior to removal. This involves the use of a basket and a sheath that can
be wrapped around the stone, which are in turn attached to a handle that is turned to result
in stone fragmentation.1,2 Although shown to be effective in 84-98% of patients with large
stones, this method can be cumbersome and time-consuming.2

Endoscopic Balloon sphincteroplasty (EBS) [(Hurricane RX Balloon Dilatation Catheter; Boston
Scientific Corp., Natick, MA, USA) or CRE Wireguided Balloon Dilatation Catheter; Boston
Scientific Corp., Natick, MA, USA)] is an alternative technique in which a balloon is used to
dilate the papilla located at the bile duct opening by up to 8-20mm (depending on size of the
distal CBD) after performing an endoscopic sphincterotomy. Following dilation, the stone is
removed using a basket and/or extraction balloon. This technique was shown to be effective in
clearing the bile duct in 89-95% of patients with difficult bile stones in whom initial
endoscopic sphincterotomy was unsuccessful.3 Furthermore, in a randomized trial comparing
endoscopic sphincterotomy alone versus EBS for removal of bile duct stones, the use of
mechanical lithotripsy was significantly lower in the EBS group (28.8% for EBS vs. 46.2% for
endoscopic sphincterotomy only, p=0.028), although the overall stone clearance rates were
comparable between the two groups (89% for ESBD vs. 88.5% for ES only, p=0.279).4

The SpyGlass Direct Visualization System (Boston Scientific Corp., Natick, MA, USA) is a
single-operator peroral cholangioscopy system (POC) which allows direct visualization of the
bile duct stone.2 The main advantage of this technique is that a probe can be inserted into
the endoscope and then guided through the bile duct to reach the stone. Using this probe, the
energy from laser (laser lithotripsy) can be accurately focused onto the stone to cause stone
fragmentation under direct visualization.1 The use of SpyGlass system with laser lithotripsy
has been shown to be successful in the clearance of difficult bile duct stones in 73-100%
patients.4-9

Although various methods for removal of bile duct stones exist, there have been thus far no
studies directly comparing EBS with cholangioscopy-guided laser lithotripsy for clearance of
bile duct stones. The aim of this study is therefore to compare efficiency of the
single-operator peroral cholangioscopy-directed laser lithotripsy (POC-LL) using the SpyGlass
Direct Visualization system versus EBS for clearance of difficult bile duct stones.

Inclusion Criteria:

- Age > 19 years,

- Common bile duct stones that measure more than 1.2 cm at ERCP.

Exclusion Criteria:

- Patients unable to provide informed consent due to any diminished capacity,

- Pregnant patients or age < 19 years or prisoners,

- Presence of bleeding disorders,

- Patients with altered post-surgical anatomy.