You Can't Mess With the Brainstem

One small error in the brainstem and you can make a patient locked in. They can move their eyes, but they can't move anything else. It's that delicate a structure that one millimeter too far and you can create that sort of scenario where someone is essentially worse in death. So for over 120 years now, since the start of neurosurgery, the leaders in neurosurgery have always said, don't touch the brainstem or tumors of the brainstem. That's how bad it is. You can't mess with it.