Preparation of EUS-guided radiofrequency probe and test of its functions

Abstract

Objective To prepare a radiofrequeney （RF） ablation probe guided by endoscopic ultrasonography （EUS） and to evaluate its efficacy and safety. Methods A modified 19-gange needle （ Olympus） was used, which was electrically insulated with shrink tubing, with the tip of lcm naked. The insulation was tested, and the current signal was stable. Three rabbits were anesthetized with 8% chloral hydrate （3 ml/kg） intraperitoneally, fixed on the dissecting table. A standard neutral pad was applied to the thigh of the rabbit to complete the electrical circuit, both the pad and the needle electrode connected with RF generator. After anesthesia was ready, the needle was advanced through the gastric wall into the liver. Ablations were performed three times in the same zone. Extent and tissue lesion were measured after ablation. Results Ablation could be successfully performed by the needle electrode, with brown lesions surrounded by normal hepatic tissue. The mean diameter of the ablated zone in the liver was 1.0 cm × 1.2 cm. After ablation, specimens along the passage were subjected to NADH staining, and no lesions were found. HE and NADH staining showed no viable cells in the central ablation area. Conclusion With the advance of the technology and selection of materials, an EUS-guided needle electrode can be made. This preliminary animal trial dem- onstrates that radiofrequency ablation can be performed effectively and safely by using this EUS-guided needle electrode. Key words: Endoscopic ultrasonography ; Electrodes ; Catheter ablation, radiofrequency