[must save Joey]

I logged onto this site as I have learned that Liver Shunts can be common in Yorkies and hope to get advise from those that have experienced this misfortune. My Joey is 4 1/2 years old (5.5 lbs.) and has experienced seizures for the past 2 years that have become more frequent. He is currently on phenobarbital. A year ago I was referred to a canine neurologist who discovered that Joey's bile acids were elevated suspecting that he has a liver shunt. It is unknown whether this is causing his seizures or if they are strictly caused by some neurological defect. He has even been through an MRI which didn't show any abnormality except for a minor Cairy 1 brain stem abnormality which the neurologist said was insignificant to his problems. Joey also had great difficulty coming through the anesthetic last time he had his teeth cleaned likely d/t to this supected liver shunt. Just recently we visited the University of Florida where they recommended a scan which requires general anesthetic to be followed immediately by corrective surgery if a shunt is found and if he is tolerating the anesthetic.
I am very apprehensive to act at this time because Joey looks great, is happy, and just seems to good to rock his little world. He has not seized since 12/16 which prior to that one seemed to be starting to occur monthly with each seizure lasting at least 7 hours.
My first concern is that he may not survive the anesthetic. Secondly, if they find and correct a problem it might cause more problems if in fact the shunt had formed d/t problems in the liver. I don't want to put Joey through any unneccesary misery. Sometimes it is better just to leave well enough alone yet if I can give him a longer heathier life I will. Hopefully your shared experiences can help with our decision for Joey.