Thirty years after surgery I still walk like a, "Drunken sailor", as my physical therapist puts it. I do not fall as often as 30 years ago, but I still loose my balance frequently.
Part of my cerebellum was removed. As I understand it the inner ear and the cerebellum provide the primary balance sensors for the individual. With loss of one inner ear and half the cerebellum, half the primary balance features no longer exist. At that point the seconday sensors, vision, and balls of the feet, become effective.
I figure this explains why my balance is worse at night, and the most horrific walking down stairs in a darkened movie theater. I do not like walking across grassy areas either, especially if soft and uneven.
This still exists after 30 years, but I actually do not hit the ground near as often as in the beginning. Maybe it is just experience.
