and the bone and the paving is on the part that covers the of rain a small whereof tissue called duramatter. it is no different than dental work people tell me it is more painful to have dental work bet with the surgeon. but it is amazing a few weeks ago a young man 50 years old will be featured in the john hopkins newsletter. he was awake to the craniotomy with me. talk about a true hero. added to answer the questions to keep him awake and ask questions all this goes they work with me. to eradicated the disease. they do a beautiful job. c-span: how long can a patient stayed awake and have the braves open? >> guest: depends the surgery will range between one and three men -- hours depending on the timber or how precise so they can be a way. sometimes a little anesthesia. is crucial to keep them wray said relaxed. c-span: of the most difficult period surgeries' how many people are involved? >> guest: imagine that. yesterday morning i did a case that lasted 12 hours and i was the captive of this team and i had to ent surges into plastic surgeons and i was leading a team of neurosurgeons. in t