Like any surgical procedure, a gastrojejunostomy could result in infection or another complication. A gastrojejunostomy connects the stomach to the jejunum, bypassing the duodenum, the beginning of the intestine at the bottom of this image.
One more thing: Don't make your turtle's water temperature too warm. For most adult aquatic turtle species, 78 F. (25.5 C.) is the highest you want unless you're treating them for an illness and a veterinarian has told you to raise the temperature. Otherwise, too-warm water can encourage bacteria growth in the tank. It also discourages turtles from basking sometimes.
The pond for snapping turtles should be at least 4 x5 for one adult turtle and larger for multiple specimens. Water depth should slope from around 6 deep to 18 or deeper. If the turtle is to over winter in this pond, the water must be deep enough so that it will not freeze all the way to the bottom.