Arachnoid cyst returned?

[ACdaughter]

Hi everyone,

So, I am writing for my dad who was diagnosed with a posterior fossa arachnoid cyst in 2017 since he was having memory problems (forgetting conversations, how to drive, etc.), movement difficulties, constantly fatigued, and a migraine. He went to his PCP who sent him to a neurosurgeon and he had the cyst removed in May 2017. They were unable to get the entire cyst due to it's location. After surgery he started seeing double and it still hasn't fully resolved. He has also been having 8-9/10 migraines multiple times a week since the surgery. A second surgery was performed to severe the greater occipital nerve which the neurosurgeon thought had grown back through the scar tissue, to no avail. At a follow-up with the neurosurgeon a few months ago, the CSF has returned but since he was asymptomatic he did not want to do anything.

Fast forward a few months, he is again having symptoms. I was wondering if anyone has had the shunt or burr hole completed, what was your experience? Also, has anyone had an arachnoid cyst return in less than a year after surgery and how did treatment differ? Finally, my dad had severe ice dams in his home and wants to know if anyone had mold exposure before their diagnosis (I know it is usually congenital but previous MRIs 2007-2009 don't show the cyst).