First - since I knew what they were but not what they were called,
'A dewclaw is a vestigial digit on the foot of many mammals, birds, and reptiles (including some extinct orders, like certain theropods). It commonly grows high on the leg so that in digitigrade species, when the animal is standing, it does not make contact with the ground. Dewclaws are perhaps best known in dogs, and they are often removed in young puppies, though there is debate on whether this is necessary.'
Eddie, had his dew claws removed when he was a pup - by the breeder - usually it is done when they are a few days old. When removing dew claws you have to ensure the entire root of the nail has been cut off or the nail can grow back - unfortunately this is what happened in Eddie's case.
In Eddie's situation the initial dew claw removal area had healed and the dew claws began to grow back under the skin.
It turned out to be far less nasty than it sounds because it never seemed to bother him or cause any irritation for the first 2 years of his life. The problem began when our local dog park was renovated with wood chips - running around in the loose chips, I'm assuming, rubbed the dew claw area and started to cause some pain.
After a couple Google searches and feeling the area it seemed pretty obvious what was happening. I took Eddie to the vet, the vet confirmed what was going on so we scheduled surgery - no preliminary x-rays, which I thought may have been deemed 'necessary'.
Standard post surgery story - antibiotics for 10 days - no running. One paw healed perfect - the other took a few days longer before the stitches were removed. Now he's good as new.