Remove the stems and discolored outer leaves from the Brussels sprouts. Cut them in half and pull off as many of the outer leaves as desired, placing all into a bowl of cold water. (I prefer a mixture of leaves and whole sprouts.) Rinse thoroughly. In a large pan over medium heat, add the oil and sauté the onion until lightly golden. Add the sausage and cook until lightly browned. Add the wine and allow to evaporate. Add the Brussels sprouts and 1 cup of water. Add salt and pepper to taste. Cover and let cook for about 5 minutes. Remove the lid and continue cooking for another 5 minutes until the liquid is mostly absorbed and sprouts gain some golden color.
Bring a large pot of salted water to boil. Cook the pasta until al dente, and drain it, retaining one cup of the cooking water. Add the pasta to the Brussels spouts and mix together. Add some of the retained cooking water to taste. Serve immediately with a sprinkle of Parmigiano.