Toraks Cerrahi̇si̇ İçi̇n Uygulanan Epi̇dural Lokal Anestezi̇kleri̇n Karşilaştirilmasi: Bupi̇vakai̇n İle Levobupi̇vakai̇n a Comparison of Epidural Local Anesthetics Administered for Thoracic Surgery: Bupivacaine Versus Levobupivacaine Kli̇ni̇k Çalişma / Clinical Research