All brain surgery is risky, there is no denying that. But if you are having so much pain and other symptoms, and possilby problems with the shunt...You probably need to go ahead with the surgery. I had an arachnoid cyst, and had fenestration surgery where most of the cyst was removed. Luckily I didn't need to have a shunt. I was petrified at the time too, but I had to have the surgery, and now I'm so glad I did.
It's good to hear you have found a neurosugeon who is willing to try and remove the cyst and the shunt. Hopefully he is skilled surgeon, and knows what he's talking about.
Yes, I'm praying for you, and praying that the surgery will go well, and in time, you will be pain and symptom free!
~Jaime~