Development of a pancreatic tumor animal model and evaluation of NOTES tumor enucleation

Abstract

Background: Laparoscopic distal pancreatectomy is associated with high morbidity and mortality. NOTES tumor enucleation may provide an alternative to laparoscopic distal pancreatectomy. The goal of this study was to determine the feasibility of NOTES tumor creation and enucleation as a multidisciplinary approach.

Methods: A linear-array endoscopic ultrasound (EUS) endoscope was used to inject a thermosensitive ABA triblock polymer mixed with methylene blue through the stomach wall and into the distal pancreas using a 22-gauge EUS needle. Due to its thermosensitive character, the polymer solidifies in response to body temperature, creating an artificial tumor. Seventeen swine underwent NOTES transgastric pancreatic tumor enucleation. Nine nonsurvival animals were sacrificed immediately after the NOTES procedure, with subsequent necropsy. Eight survival animals were observed for up to 16 days after the procedure, subsequently sacrificed, followed by necropsy.

Results: The procedure was performed successfully in all 17 pigs studied, 9/9 nonsurvival (100%) and 8/8 survival (100%) animals, using a pure NOTES approach without any laparoscopic ports. Complications included two esophageal dissections (1 in nonsurvival group, 1 in survival group) caused by the introduction of the endoscopic overtube (2/17, 12%), unrelated to the actual surgical procedure. In the survival animals, there were two small splenic lacerations caused during retraction with the endoscopic forceps, for which hemostasis was achieved prior to closure of the gastrotomy (2/7, 29%). At necropsy of the animals, there was sufficient closure of 15/17 gastrotomy sites (88%).

Conclusions: The creation of artificial pancreatic tumors via EUS guidance is feasible. Pancreatic tumor enucleation using a transgastric NOTES approach is technically feasible and could be an alternative to laparoscopic distal pancreatectomy with further development. Further adoption and adaptation of this technique will require the development of more sophisticated specialized tools to improve the safety profile of the procedure.