Extracorporeal shock wave lithotripsy of pancreatic duct stones and patient factors related to stone disintegration

Stones in the main pancreatic duct (MPD) are difficult to remove by endoscopic devices alone in some patients who have chronic pancreatitis. We treated these patients with extracorporeal shock wave lithotripsy (ESWL) and analyzed the patient factors related to disintegration. Twenty-four patients were treated with ESWL alone or with combined endoscopic-ESWL to disintegrate or remove MPD stones. Ten patients were treated by ESWL alone and 14 by combined endoscopic-ESWL. A total of 19 patients (79%) were effectively treated by either method. The mean MPD diameter decreased significantly after ESWL. In most of the patients who had chronic abdominal symptoms, these symptoms were relieved at discharge. Severe side effects of complications did not occur during ESWL therapy. Acute abdominal symptoms and a significant increase in the white blood cell count, total bilirubin, and aspartate aminotransferase were observed only immediately after ESWL. Although there were no significant differences, we observed that the patients with a higher stone disintegration success rate showed the following factors: (1) female, (2) non-alcoholic pancreatitis, (3) younger age, (4) shorter duration of symptoms, (5) smaller stones, and (6) a lower Hounsfield unit value of stones. Although about half of the patients had recurring abdominal symptoms and stones during a follow-up period of 12 months, the stones which caused relapse in short-term intervals were disintegrated easily by ESWL. We may consider the application of ESWL therapies for patients who show the factors associated with easily disintegratable stone conditions. These therapies are highly effective and relatively safe procedures for pancreatic duct stones in such patients.