• Francesco Di Matteo, Margareth Martino, Roberta Rea, Monica Pandolfi, Francesco Panzera, Egidio Stigliano, Emiliano Schena, Paola Saccomandi, Sergio Silvestri, Claudio Maurizio Pacella, Luca Breschi, Giuseppe Perrone, Roberto Coppola, and Guido Costamagna.
• Digestive Endoscopy Unit Campus Bio-Medico, University of Rome, Rome, Italy.
• Gastrointest. Endosc. 2013 Nov 1; 78 (5): 750-5.

BackgroundLaser ablation (LA) with a neodymium-doped yttrium aluminum garnet (Nd:YAG) laser is a minimally invasive approach able to achieve a high rate of complete tissue necrosis. In a previous study we described the feasibility of EUS-guided Nd:YAG pancreas LA performed in vivo in a porcine model.ObjectiveTo establish the best laser setting of Nd:YAG lasers for pancreatic tissue ablation. A secondary aim was to investigate the prediction capability of a mathematical model on ablation volume.DesignEx vivo animal study.SettingHospital animal laboratory.SubjectsExplanted pancreatic glands from 60 healthy farm pigs.InterventionLaser output powers (OP) of 1.5, 3, 6, 10, 15, and 20 W were supplied. Ten trials for each OP were performed under US guidance on ex vivo healthy porcine pancreatic tissue.Main Outcome MeasurementsAblation volume (Va) and central carbonization volume (Vc) were measured on histologic specimens as the sum of the lesion areas multiplied by the thickness of each slide. The theoretical model of the laser-tissue interaction was based on the Pennes equation.ResultsA circumscribed ablation zone was observed in all histologic specimens. Va values grow with the increase of the OP up to 10 W and reach a plateau between 10 and 20 W. The trend of Vc values rises constantly until 20 W. The theoretical model shows a good agreement with experimental Va and Vc for OP between 1.5 and 10 W.LimitationsEx vivo study.ConclusionVolumes recorded suggest that the best laser OP could be the lowest one to obtain similar Va with smaller Vc in order to avoid the risk of thermal injury to the surrounding tissue. The good agreement between the two models demonstrates the prediction capability of the theoretical model on laser-induced ablation volume in an ex vivo animal model and supports its potential use for estimating the ablation size at different laser OPs.Copyright © 2013 American Society for Gastrointestinal Endoscopy. Published by Mosby, Inc. All rights reserved.

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