October-December 1999, Phoenix (Arizona) Dr.Spetzler.
Saint Louis University in June 2005 Professor Saleem Abdulrauf. From January 2006 to the present as Visiting Professor, with Dr. Yasargil,
Dr. Morcos, Dr. Lawton, Dr. Sampsom, Dr. Langer, Dr. Tulleken, Dr. Fukhusima, Dr. Sehkar, Dr. Jakovski.
June 2006 Utrech Professor Tulleken to learn the ELANA technique.
November 2006 Helsinki (Finland) Dr. Hernesniemi, bypass.
In 2010 Professor Tulleken Utrech to perfect the ELANA technique.