Bring a large pot of salted water to a boil. Prepare pasta according to package instructions, and reserve 1 cup of cooking water.
Meanwhile, heat the oil in a large pot over medium-high heat. Add the sausages and cook fully, adding some of the pasta water to deglaze the pot, if needed. Remove and slice on the diagonal, set aside.
Reduce heat to medium-low, and to the same pan, add garlic, onion, celery, and carrots - cook until vegetables are soft and onions are translucent, about 7 minutes. Add the wine and let it sizzle out.
Add the Italian seasoning, red pepper flakes, salt, and pepper. Stir in the tomatoes and allow to simmer for 20 minutes so the sauce reduces. Add the spinach and pasta to the sauce and return sausage to pan. It should be saucy, but not runny. Transfer to large serving dish and top with Parmesan and fresh basil.