New Aspects of Extracorporeal Shockwave Lithotripsy of Gallstones

Abstract

Extracorporeal Shockwave lithotripsy (ESWL) with adjuvant oral bile acid medication has become an attractive alternative to cholecystectomy for a selected group of patients with symptomatic gallstone disease. One year after ESWL and treatment with urso- and cheno deoxycholic acid 50-80% of patients with gallbladder stones can be expected to be free of stones, depending on the selection criteria and type of lithotripsy system. As more ESWL devices are becoming commercially available, a comparison of the efficacy and safety of the different systems is mandatory. However, thorough data on the pressure distribution in the focal region are lacking for most systems. We investigated the pressure distribution in the Shockwave focus of two types of lithotriptors. The effects of Shockwaves on living tissues were evaluated in an animal model. Twenty-four hours after Shockwave treatment of human gallstones surgically implanted into the gallbladder of pigs, small hemorrhages could be found in the gallbladder wall and epithelial desquamation in the mucosa. In the adjacent hepatic parenchyma, focal areas of hemorrhagic necrosis were found, but these were replaced by scar formation 6 days later. The number of patients with symptomatic gallbladder stones eligible for ESWL is limited by the functional status of the gallbladder, the size and number of stones, and the amount of calcium and other non-soluble components in the stone(s). Non-functioning of the gallbladder can be predicted by ultrasonography, thereby obviating the need for oral cholecystography in most patients. In vivo computed tomography analysis can reliably predict the calcium and cholesterol content of gallstones, thus increasing the efficiency of combined ESWL and bile acid treatment. So far, 20-30% of the patients with symptomatic gallbladder stones can be successfully treated by combined ESWL and oral dissolution therapy. To patients not eligible for Shockwave therapy or refusing to take the long-term oral bile acid medication, cholecystectomy or cholecystotomy can be offered. Compared with cholecystectomy, cholecystotomy is less traumatic to the patient, as evidenced by a 50% reduction in analgetics and hospital stay after cholecystotomy. Controlled clinical trials are needed to compare the cost-effectiveness of each of the available treatment options. Data will thereby be generated that can refine medical decision analyses. On the basis of decision analytic principles a treatment plan can be offered to the individual patient.

Key Words:

• Biliary lithotripsy
• cholecystotomy
• cholelithiasis
• computed tomography
• extracorporeal Shockwave lithotripsy
• gallstone
• medical decision analysis
• pressure
• tissue
• ultrasonography