Heat olive oil in a large pot over medium high heat. Sauté onion about 2 minutes until it begins to soften. Add celery and carrots and cook, stirring frequently, for another 3 minutes. Add garlic and cook just until fragrant, about 30 seconds.
Add the sausage to the pot and cook until the sausage is no longer pink, crumbling it as it cooks. Stir in Italian seasoning, red pepper flakes, tomatoes and chicken broth.
Bring to a boil. Reduce heat and simmer 30 minutes.
Stir in the beans and pasta. (Add an extra cup of stock or water if it’s boiled down too much.) Simmer for 6- 8 minutes or until pasta is almost tender. Add zucchini and spinach and cook until zucchini is tender and spinach is wilted.