Shyam Varadarajulu1, Nirag C Jhala, Ernesto R Drelichman. 1. Division of Gastroenterology-Hepatology, University of Alabama at Birmingham School of Medicine, Birmingham, Alabama 35294, USA. svaradarajulu@yahoo.com
Abstract
BACKGROUND: Although previously reported in an animal model, the development of EUS-guided radiofrequency ablation (EUS-RFA) has been impeded because of a lack of a retractable needle electrode array that could safely and effectively ablate large areas. OBJECTIVE: To evaluate the feasibility and safety of performing EUS-RFA with a 19-gauge FNA needle fitted with an umbrella-shaped retractable needle electrode array. DESIGN AND SETTING: Endoscopic experimental study in a porcine survival model at a tertiary referral center animal laboratory. MAIN OUTCOME MEASURES: Evaluate the safety and efficacy of the retractable needle electrode array for performing EUS-RFA. INTERVENTIONS: A 19-gauge EUS-FNA needle was modified and fitted with a retractable echogenic umbrella-shaped monopolar electrode array at its tip. The FNA needle was connected to a 200-W generator that has an impedance-based feedback system. EUS-RFA of the liver was attempted on 5 Yorkshire pigs. Although 1 pig was euthanized immediately after RFA to assess for immediate complications and pathological examination, the 4 others were kept alive for 7 days. RESULTS: At EUS, the needle electrode was well visualized and could be deployed in the liver without technical difficulty. During ablation, a round hyperechoic focus gradually surrounded the electrode tip. Tissue ablation was attained within 7 minutes, and the electrode array could be easily withdrawn into the needle assembly. The vital signs of all pigs remained stable throughout the procedure and until they were euthanized. Histopathology in all pigs revealed a discrete, well-demarcated spherical focus of complete coagulation necrosis measuring 2.6 cm in diameter and without damage to the surrounding liver parenchyma or vasculature. CONCLUSIONS: In this experimental study, EUS-RFA of the liver was performed safely by using the retractable umbrella-shaped electrode array with effective coagulation necrosis of large areas.
BACKGROUND: Although previously reported in an animal model, the development of EUS-guided radiofrequency ablation (EUS-RFA) has been impeded because of a lack of a retractable needle electrode array that could safely and effectively ablate large areas. OBJECTIVE: To evaluate the feasibility and safety of performing EUS-RFA with a 19-gauge FNA needle fitted with an umbrella-shaped retractable needle electrode array. DESIGN AND SETTING: Endoscopic experimental study in a porcine survival model at a tertiary referral center animal laboratory. MAIN OUTCOME MEASURES: Evaluate the safety and efficacy of the retractable needle electrode array for performing EUS-RFA. INTERVENTIONS: A 19-gauge EUS-FNA needle was modified and fitted with a retractable echogenic umbrella-shaped monopolar electrode array at its tip. The FNA needle was connected to a 200-W generator that has an impedance-based feedback system. EUS-RFA of the liver was attempted on 5 Yorkshire pigs. Although 1 pig was euthanized immediately after RFA to assess for immediate complications and pathological examination, the 4 others were kept alive for 7 days. RESULTS: At EUS, the needle electrode was well visualized and could be deployed in the liver without technical difficulty. During ablation, a round hyperechoic focus gradually surrounded the electrode tip. Tissue ablation was attained within 7 minutes, and the electrode array could be easily withdrawn into the needle assembly. The vital signs of all pigs remained stable throughout the procedure and until they were euthanized. Histopathology in all pigs revealed a discrete, well-demarcated spherical focus of complete coagulation necrosis measuring 2.6 cm in diameter and without damage to the surrounding liver parenchyma or vasculature. CONCLUSIONS: In this experimental study, EUS-RFA of the liver was performed safely by using the retractable umbrella-shaped electrode array with effective coagulation necrosis of large areas.
Authors: Petr Vavra; Marek Penhaker; Jan Grepl; Jana Jurcikova; Jiri Palecek; Michal Crha; Jana Nowakova; Martin Hasal; Martina Skrobankova; Petr Ostruszka; Peter Ihnat; Patricie Delongova; Dana Salounova; Nagy A Habib; Pavel Zonca Journal: Biomed Res Int Date: 2014-04-09 Impact factor: 3.411