Brain surgery on Baltimore County Executive Roger B. Hayden is over and "went very well," according to an announcement at a County Council meeting today.

County Administrative Officer Mereen E. Kelly made the announcement as the council met to formally adopt a $1.26 billion budget.

Mr. Kelly said the county executive is "in intensive care and resting comfortably." Mr. Hayden, 49, entered Johns Hopkins Hospital under an assumed name Sunday for an operation to remove malformed blood vessels from his brain, a hospital spokeswoman said yesterday.

He was first hospitalized May 8, when a blood vessel broke in his brain, causing a painful headache and a partial loss of his right-side vision.

The congenital condition was diagnosed 20 years ago, Mr. Hayden said, but had not caused a problem previously other than headaches.

Doctors earlier said the operation typically involves removing a piece of the skull, surgically removing from the brain's surface the enlarged tangle of blood vessels causing the problem and sealing off the remaining vessel endings with heat.