Hey! Well, I don't have the exact shunt type you have but I can tell you what happened with me when my shunt was changed from a VentriculoPeritoneal to a VentriculoPleural shunt. My shunt was moved for basically the same reason yours sounds like it is. The scar tissue wasn't allowing the CSF to absorb the way it was suppose to and(in my case) causing Pseudocysts.

Now for me they didn't cut my stomach again. They just pulled it out from where they cut me at my valve. Let me know how it works out for you! I've had some issues with my shunt since it was converted in 2007 and come very close to having it changed to a VentriculoAtrial shunt a few times, so I'm interested in hearing how it all goes for you!