1. From the Department of Neurosurgery, College of Physicians & Surgeons, Columbia University, NY (Dr Holtzman); the Departments of Surgery (Drs Holtzman and Heymann) and Pathology (Dr Wahl), Lenox Hill Hospital, New York, NY; Clinica Villa Rizzo, Siraccusa, Sicily (Dr Bordone); I Clinica Medica (Dr Marinoni) and Ricercatore Dipartimento Chirugia “Pietro Valdoni” (Dr Barillari), Università “La Sapie