A G-tube (gastrostomy tube) is a tube inserted through the abdomen that delivers nutrition directly to the stomach when a person for whatever reason cannot get adequate nutrition by mouth or has a medical issue that requires nutrition to not be taken by mouth.

In Evanna's case, she currently has a g-tube because her vocal cord paresis (weak vocal cords) risks aspiration of liquids and foods into her lungs.

And this is how a g-tube is changed out...