Here is a website for you to do some research on regarding causes and solutions for Bladder Stones.
http://dogs.about.com/cs/disableddog...der_stones.htm
It will be very
important to listen to what your vet tells you about what to feed your dog. In this case, from what I read none of the food we feed our Yorkies will work for you as Protein could be a contributor to your Bladder Stones. It appears you will have to have him on prescription food.
Good Luck with your little one.