Ugh..that's awful!! They definitely should be looking into that for you...your herniation may stay the same but it shouldn't get larger unless there was another reason. I'm with the other two..have they looked for tethered cord? I have heard that can pull the brain down, having the decompression can make more room for it to be pulled down further. Or cerebellular slump..if they took too much skull out the brain may slump down. Either way, there is an issue...have you thought about changing NS? To me, if either of these conditions happened and were undetected, it would make me a little nervous. Might be time to have a fresh set of eyes take a look at your case.
Carolyn
Decompression surgery doesn't cure Chiari, it hopefully helps the symptoms, but if the cerebellum is still being squeezed (or pulled by tethered cord) then the herniation can still increase.
You may have to have yet another operation. I know that's not what you want to hear, but it sounds likely.
I can only think of a few reasons....cerebral ptosis(brain Slump), tethered cord...or a syrinx affecting CSF flow lower in the cord......
neone else???
"selma"