Decompression surgery and neck fusion?

My daughter meet with her surgeon yesterday and he informed us that in 11days we will go in for the decompression surgery and tonsil reduction and he may also fuse her c1 c2 due to the fact that they are slightly misformed and she has a lot of extra muscle therewhich causes them to move more than normal( normal is 2mm or less hers measures 9 mm) has anyone had this combination of surgeries??Also what can i expect from the decompression surgery??
Thanks!!

My daughter is 5 she will be 6 on June 11th the doctor said that her C4 and C5 would make up for the motor range of motion loss she may get. We have not gotten a second opinion due to tu fact that we I’ve in Wyoming and there is only 1hospital with pediatric neurosugens within 300 miles. all the nerosurgons have discussed her complex case and are agreeing on the compression and the wait and see on the neck fusion once they are in there. They also stated if they do the fusion she will never be able to ave another surgery for her chiari which makes me even more nervous. i just want to make sure we are making the right choice its only been about 2 months since she was diagnosed and its been a whirl wind since then. Is that normal??