In a large saucepan or stockpot, cook the Italian sausage over medium-high heat, breaking it up with a wooden spoon as it cooks. Cook until the sausage is no longer pink, about 7 minutes.
Add the onion, oregano, carrots, garlic, spinach leaves, diced tomatoes with their juices, canned beans, and pasta. Stir to combine.
Add the dried basil, celery and season with salt and black pepper to taste. Pour in the chicken broth and bring the soup to a boil.
Reduce heat to medium-low and simmer uncovered until the pasta is tender, about 20 minutes.
Serve hot with freshly grated Parmesan cheese and crusty bread on the side.