When the stones finally got too big for comfort, vets decided to go in and take them out. They cut a 3 x 4 inch "door" in the tortoise's underbelly, and removed the stones. They weighed just a bit over a pound: quite a heavy load for a normally 8 pound tortoise! After the removal, the vet "stitched" Cactus back up with a bit of fiberglass and epoxy, sort of like "fixing a ding on a surfboard."

Cactus, in the meantime, is on his way to a complete recovery. You can see more pictures of Cactus, including the stones and xrays, here.