I'm so glad to hear your success story!!! It keeps me optimistic. My yorkie also has a liver shunt, and he had the surgery, but unfortunately they weren't able to find the shunt when they went in. I guess he was in the 15% that you were talking about.
The vet knows for sure that he has a shunt though. His bile acid test results came back at over 300, and he has a lot of bladder stones, and he had a couple of seizures until we put him on denosyl ( a liver supplement), lactulose, and Royal Canin hepatic diet (very low in protein). My vet is guessing that the shunt must be intrahepatic (in the liver) and he says its too risky for him to get in there as he is not experienced with intrahepatic shunts. He has also ruled out liver disease.
He's 1 yr and 2 months old and he's been living with it all his life. We only found out 3 months ago though...Because he never had any symptoms up to that point, we had no clue! Our vet is very optimistic because other than the bladder stones (which were taken care of) and the lab results, he doesn't show any of the symptoms associated with liver shunts. He's very energetic and constantly on the go, he's grown to his full capacity (almost 9 lbs!), he doesn't have seizures anymore.
We're researching to find out if there's another facility around here that has more experience with intrahepatic shunts. The vet said that some yorkies that have liver shunts can be medicated and live almost 9 years without any problems or pain or anything at all depending on how bad it is.
Believe me though, he's the most spoiled baby! He's got all the love in the world, all the toys in the world, and anything he wants. We will never give up on our baby!!!