In a large bowl, combine pork, apple, onion, garlic, teriyaki sauce and egg. Mix well. I find it works best to start mixing with a spoon and then use your hands to make sure everything is evenly mixed.
Shape into 4 burgers and place into a skillet. Heat on medium heat, for about 5 minutes on each side or until cooked through.
Top burgers with Swiss cheese, a pineapple slice and fresh spinach on a bun.