Development of an in vivo tumor-mimic model for learning radiofrequency ablation.
Radiofrequency ablation requires accurate probe placement using ultrasound guidance. The purpose of this study was to develop an in vivo tumor-mimic model for learning open and laparoscopic radiofrequency ablation. Tumor-mimics were created in ex vivo porcine livers by injecting a mixture of 3% agarose, 3% cellulose, 7% glycerol, and 0.05% methylene blue, which formed 1 cm hyperechoic, discrete lesions on ultrasound. Open and laparoscopic (using a box-trainer) ablation techniques were practiced. In vivo experiments were then conducted in 10 pigs. Three tumor-mimics were created in each animal using a laparoscopic approach. Lesions were characterized sonographically, ablated using an open (n = 5) or laparoscopic (n = 5) approach, and examined pathologically. An ablation in normal liver tissue was performed as a control. Tissue impedance was recorded. Target creation took 81 minutes per animal and 96% of injections were successful. Tissue impedance (48.8 +/- 5.8 vs. 49.6 +/- 5.4) and ablation size (25.1 +/- 3.4 vs. 24.3 +/- 5.1) were not significantly different for controls (n = 8) and tumor-mimics (n = 26), respectively. One animal died of a pulmonary embolism following injection of agarose into a hepatic vein. The agarose-based tissue-mimic creates realistic sonographic targets for learning ultrasound-guided open and laparoscopic radiofrequency ablation in an in vivo model.
Scott DJ
M D
MD
Department of Surgery, University of Texas Southwestern Medical Center, Dallas, TX 75235-9092, USA.
Young
W N
WN
Watumull
L M
LM
Lindberg
G
G
Fleming
J B
JB
Rege
R V
RV
Brown
R J
RJ
Jones
D B
DB
D000818:Animals; D017115:Catheter Ablation / Q000295:instrumentation / Q000379:methods*; D004195:Disease Models, Animal; D004867:Equipment Design; D004869:Equipment Safety; D013502:General Surgery / Q000193:education*; D066298:In Vitro Techniques; D008113:Liver Neoplasms / Q000000981:diagnostic imaging / Q000601:surgery*; D008953:Models, Anatomic; D012680:Sensitivity and Specificity; D013552:Swine; D013781:Texas; D014463:Ultrasonography