Hi Michelle @michelles123, I used Google Scholar (https://scholar.google.com/) which finds a lot of research type articles and books that are sometimes not free but it will show you the abstract which is sometimes useful. I thought that it showed me the complete article when I first clicked on the link. I did another search on Google Scholar using the phrase "microvascular decompression for hemifacial spasm" and it found quite a bit of information. Here are the search results:

-- https://scholar.google.com/scholar

Here's the first link that is shown and it is one that doesn't have a cost associated to view it. It's from Science Direct.

Transposition of posterior inferior cerebellar artery could have caused ischemic complication in microvascular decompression for hemifacial spasm
-- https://www.sciencedirect.com/science/article/pii/S2214751918302573

Hopefully this helps...