Billy Joel revealed that he underwent brain surgery because he didn’t want to lose his “marbles.” The “Piano Man” singer admitted he initially balked at going under the knife for hydrocephalus, a disorder he was diagnosed with in 2025. NBC News medical contributor Dr. Kavita Patel explains what the surgery entails. For more context and news coverage of the most important stories of our day, click here: nbcnews.com Every day, NBC News helps people understand what’s happening and why it matters — through fact-based reporting, meaningful conversations, and powerful stories. From its leading news broadcasts — TODAY, NBC Nightly News, Meet the Press, and Dateline — to NBC News NOW, the 24/7 streaming news channel, plus chart-topping podcasts, the NBC News app, and NBCNews.com, NBC News keeps audiences informed and connected to the stories shaping our world. NBC News. Reporting for America. » Subscribe to NBC News: nbcnews.to/SubscribeToNBC » Subscribe to Here's the S...