Heat Ablation of the Normal Gallbladder in Pigs

Abstract

The safety and efficacy of ablating gallbladder mucosa was investigated with a percutaneously placed heater catheter in an animal study. The study was performed in three stages with 39 pigs. In stage 1 (15 heat-treated animals, one control), the configuration of the heater catheter was progressively improved and the temperature settings for stage 2 were defined. In stage 2 (11 heat-treated animals, four controls), the predetermined settings were used with mechanical mixing and cystic duct ligation to test for safety and efficacy. In stage 3 (eight animals), prior heat ablation of the cystic duct was added to reduce epithelial regeneration. Gallbladder ablation was achieved at temperatures below 60 degrees C. Mechanical mixing of the intraluminal contents was essential for even heat distribution for ablation and to reduce the incidence of adjacent organ damage. Thermal injury to adjacent organs occurred when gallbladder ablation temperature exceeded 54 degrees C and serosal temperatures of adjacent organs exceeded 43 degrees C. Thermal ablation at 54 degrees C for 35 minutes was completely successful in 25%, partially successful in 50%, and failed in 25% of animals. Cystic duct ablation improved overall results and appears vital in removing duct epithelium as a source for regeneration of the mucosal lining. Defunctionalization of the retained gallbladder is potentially achievable with use of thermal techniques, but the thermal range between complete gallbladder ablation and adjacent organ injury is narrow.