A handle assembly for a surgical stapler, the handle assembly comprising: a stationary handle; a movable handle pivotably coupled to the stationary handle and pivotable between an open position spaced apart from the stationary handle and a closed position adjacent the stationary handle; an actuation mechanism comprising: an actuation shaft defining a longitudinal axis, the actuation shaft comprising an advancing surface formed thereon and a reversing surface formed thereon; an advancing driver operably coupled to the movable handle and translatable in a first longitudinal direction with respect to the longitudinal axis responsive to movement of the movable handle from the open position to the closed position; a reversing driver operably coupled to the advancing driver and translatable in a second direction with respect to the longitudinal axis responsive to movement of the movable handle from the open position to the closed position, the second direction opposite the first direction; and a gear operably coupling the advancing driver to the reversing driver; and wherein the actuation shaft is longitudinally translatable along the longitudinal axis relative to the stationary handle; and characterized in that the actuation shaft is selectably rotatable about the longitudinal axis between a first orientation in which the advancing driver engages the advancing shaft of the actuation shaft to advance the actuation shaft longitudinally distally and a second orientation in which the reversing driver engages the reversing surface of the actuation shaft to retract the actuation shaft longitudinally proximally. a stationary handle; a movable handle pivotably coupled to the stationary handle and pivotable between an open position spaced apart from the stationary handle and a closed position adjacent the stationary handle; an actuation mechanism comprising: an actuation shaft defining a longitudinal axis, the actuation shaft comprising an advancing surface formed thereon and a reversing surface formed thereon; an advancing driver operably coupled to the movable handle and translatable in a first longitudinal direction with respect to the longitudinal axis responsive to movement of the movable handle from the open position to the closed position; a reversing driver operably coupled to the advancing driver and translatable in a second direction with respect to the longitudinal axis responsive to movement of the movable handle from the open position to the closed position, the second direction opposite the first direction; and a gear operably coupling the advancing driver to the reversing driver; and an actuation shaft defining a longitudinal axis, the actuation shaft comprising an advancing surface formed thereon and a reversing surface formed thereon; an advancing driver operably coupled to the movable handle and translatable in a first longitudinal direction with respect to the longitudinal axis responsive to movement of the movable handle from the open position to the closed position; a reversing driver operably coupled to the advancing driver and translatable in a second direction with respect to the longitudinal axis responsive to movement of the movable handle from the open position to the closed position, the second direction opposite the first direction; and a gear operably coupling the advancing driver to the reversing driver; and wherein the actuation shaft is longitudinally translatable along the longitudinal axis relative to the stationary handle; and characterized in that the actuation shaft is selectably rotatable about the longitudinal axis between a first orientation in which the advancing driver engages the advancing shaft of the actuation shaft to advance the actuation shaft longitudinally distally and a second orientation in which the reversing driver engages the reversing surface of the actuation shaft to retract the actuation shaft longitudinally proximally.