Needle knife sphincterotomy for an impacted ampullary stone with difficult selective biliary cannulation.

Endoscopic treatment is highly effective for extracting common bile duct (CBD) stones and is the most common therapeutic method for CBD stones. For patients with CBD stones, the treatment goal is to completely clear the biliary duct. In general, the successful extraction rate using a basket and/or balloon catheter is as high as 90%. However, stones that are resistant to conventional endoscopic treatment procedures can be both challenging and time-consuming to treat; and successful treatment can require a combination of techniques, including mechanical lithotripsy or extracorporeal shock-wave lithotripsy. We performed needle knife sphincterotomy and attempted to remove a CBD stone using biopsy forceps and alligator grasping forceps without a lithotripter in a patient with a large impacted stone at Vater's ampulla. After attempting several techniques, the stone was successfully removed with balloon extraction.