In a pot of salted boiling water, cook the spaghetti until al dente. Drain.
In a large skillet, heat the oil. Add the pork, garlic and ginger and cook over moderate heat, stirring, until browned, about 5 minutes. Stir in the pasta, fish sauce, lime juice and spinach; season with salt and pepper and toss well. Transfer to bowls, garnish with basil and serve.