He just had surgery to remove bladder stones which have been sent off to see what kind they are. (homemadedogfood.com)
Our bladder stone page has much more detail, including a movie of removing bladder stones from a dog. (lbah.com)
Removing bladder stones involves opening the abdomen and urinary bladder and it will take your cat several days to recover. (texaswestveterinarian.com)