Billy Joel underwent brain surgery due to a diagnosis of hydrocephalus. The 77-year-old singer initially hesitated at the idea of surgery, which involved drilling a hole through his skull and inserting a shunt into his brain. After researching the condition, he decided to proceed with the surgery to help improve his balance and memory. Joel's decision was motivated by a desire to maintain his mental faculties, as he expressed a desire not to lose his "marbles".

Further details about Joel's diagnosis and surgery are available. The singer discussed his experience on his SiriusXM channel, providing insight into his decision-making process.