A surgical instrument includes a housing, an elongated shaft extending distally from the housing, an end effector assembly, and a trigger assembly. The trigger assembly is disposed in mechanical cooperation with the housing and is configured to longitudinally translate a drive member. The trigger assembly includes a trigger, a gear assembly, a spool, a slider, and a flexible drive member. The trigger is disposed in mechanical cooperation with the gear assembly. The flexible drive member is configured to engage the gear assembly, the spool, and the slider. Movement of the trigger with respect to the housing results in movement of the flexible drive member with respect to the housing and longitudinal movement of the slider with respect to the housing.