Development and validation of an experimental model for the assessment of radiofrequency ablation of pancreatic parenchyma

Objectives: The aim of this study was to develop and validate an ex vivo model for the assessment of radiofrequency (RF) ablation of the pancreas. Methods: Porcine pancreata were used within 1 hour of sacrifice. RF was delivered to a premarked area in the center of the pancreatic head using a thermocouple-tipped multiprobe array. Four temperature presets were evaluated: 70°-100°C in 10° increments. Immediately after ablation serial sections of the pancreatic head were cut to incorporate duodenum, portal vein, and bile duct. For each experiment, a portion of pancreatic tail was sampled as nonablated control. Hematoxylin and eosin (H&E) slides together with nicotinamide adenine dinucleotide (NADH) stained preparations were made. The NADH staining was quantified using computerized digital image recognition techniques. Results: Control sections (n = 20) demonstrated normal pancreatic architecture on H&E and strong NADH staining indicating preserved tissue oxidative metabolism. RF produced a temperature-dependent destruction of parenchymal architecture (H&E) with a corresponding loss of NADH activity. There was no evidence of thermal injury to the duodenum. Quantification of NADH staining demonstrated a median positive staining of 69.26% (55.87-97.28) for control tissue compared with 1.40% (0-7.77) for ablated pancreas (P <0.001; Mann-Whitney U test). Conclusion: This study describes the development of a relatively simple, reliable, and reproducible model for evaluation of RF ablation of pancreatic parenchyma. Copyright © 2005 by Lippincott Williams & Wilkins.