UPDATED: Ron Jeremy In Critical Condition at Local Hospital

LOS ANGELES—Legendary adult performer Ron Jeremy is undergoing surgery at Cedars Sinai for a condition called aortic dissection. His condition is listed as critical. Celebrity gossip site TMZ.com broke the story this morning, reporting that Jeremy drove himself to the hospital Tuesday afternoon after experiencing severe chest pain. He underwent surgery this morning for what doctors believed was a heart aneurysm, and the aortic dissection was reportedly discovered later. His surgeon is expected to make a statement sometime later. Aortic dissection is a serious condition in which there is a separation of the aorta walls. A tear in the inner wall of the aorta causes blood to flow between the three layers of the wall of the aorta, forcing the walls apart. The exact cause is unknown, but is often attributed to aging, high blood pressure and hardening of the arteries. The condition is life threatening but can sometimes be managed through surgery and drugs.  The 59-year-old Jeremy, who was nicknamed "The Hedgehog," has been a household name for years, not only for his work in the adult industry, but also his mainstream accomplishments in TV and movies. One of his most recent public appearances was at the AVN Adult Entertainment Expo and the AVN Awards, where he was joined on stage by reality TV stars Joseline and Stevie J from Love & Hip Hop Atlanta to present an award. While he still performs on occasion and still gets cast in many non-sex roles in adult movies, he has also been an advocate for the industry, touring college campuses as part of the "Great Porn Debate" with Craig Gross, founder of XXXChurch.com and an anti-pornography crusader. Jeremy got his start in the adult industry in 1979 and has appeared in more than 2,000 films. AVN will update the story as more details become available.