Eighty patients , both genders , @-@ years old , ASA I or II , for hemorrhoidectomy were randomly divided into two groups : Control ( n = @ ) , epidural anesthesia with @ mL of ropivacaine @ % plus @ mL/kg of @ % saline solution ; Experimental ( n = @ ) epidural anesthesia with @ mL of @ % ropivacaine plus @ mcg/kg of clonidine .