An assembly for operably connecting an end effector to an electrosurgical instrument, the assembly comprising: an adapter assembly (100, 300) including, a connector assembly (110, 320); a drive transfer assembly (130, 330) operably received through the connector assembly and including first, second, and third rotatable shafts; a first pusher assembly (160, 340) operably connected to the first rotatable shaft for converting rotational motion from the first rotatable shaft to longitudinal movement to perform a first function, the first pusher assembly including first proximal and distal housing sections (162, 164), a first planetary gear assembly operably mounted within the proximal housing section and a first drive screw operably connected to the first planetary gear assembly; a second pusher assembly (180, 350) operably connected to the second rotatable shaft for converting rotational motion from the second rotatable shaft to longitudinal movement to perform a second function, wherein the second pusher assembly is substantially similar to the first pusher assembly, the second pusher assembly including second proximal and distal housing sections (182, 184), a second planetary gear assembly operably mounted within the second proximal housing section and a second drive screw operably connected to the second planetary gear assembly; and a drive member operably connected to the third rotatable shaft for transferring rotational motion from the third rotatable shaft to perform a third function; wherein rotation of the first drive screw causes longitudinal movement of the first pusher member and rotation of the second drive screw causes longitudinal movement of the second pusher member; and a drive member operably connected to the third rotatable shaft for transferring rotational motion from the third rotatable shaft to perform a third function; and an extension assembly including, at least one flexible band assembly operably connected to one of the first and second pusher assemblies. an adapter assembly (100, 300) including, a connector assembly (110, 320); a drive transfer assembly (130, 330) operably received through the connector assembly and including first, second, and third rotatable shafts; a first pusher assembly (160, 340) operably connected to the first rotatable shaft for converting rotational motion from the first rotatable shaft to longitudinal movement to perform a first function, the first pusher assembly including first proximal and distal housing sections (162, 164), a first planetary gear assembly operably mounted within the proximal housing section and a first drive screw operably connected to the first planetary gear assembly; a second pusher assembly (180, 350) operably connected to the second rotatable shaft for converting rotational motion from the second rotatable shaft to longitudinal movement to perform a second function, wherein the second pusher assembly is substantially similar to the first pusher assembly, the second pusher assembly including second proximal and distal housing sections (182, 184), a second planetary gear assembly operably mounted within the second proximal housing section and a second drive screw operably connected to the second planetary gear assembly; and a drive member operably connected to the third rotatable shaft for transferring rotational motion from the third rotatable shaft to perform a third function; a connector assembly (110, 320); a drive transfer assembly (130, 330) operably received through the connector assembly and including first, second, and third rotatable shafts; a first pusher assembly (160, 340) operably connected to the first rotatable shaft for converting rotational motion from the first rotatable shaft to longitudinal movement to perform a first function, the first pusher assembly including first proximal and distal housing sections (162, 164), a first planetary gear assembly operably mounted within the proximal housing section and a first drive screw operably connected to the first planetary gear assembly; a second pusher assembly (180, 350) operably connected to the second rotatable shaft for converting rotational motion from the second rotatable shaft to longitudinal movement to perform a second function, wherein the second pusher assembly is substantially similar to the first pusher assembly, the second pusher assembly including second proximal and distal housing sections (182, 184), a second planetary gear assembly operably mounted within the second proximal housing section and a second drive screw operably connected to the second planetary gear assembly; and a drive member operably connected to the third rotatable shaft for transferring rotational motion from the third rotatable shaft to perform a third function; wherein rotation of the first drive screw causes longitudinal movement of the first pusher member and rotation of the second drive screw causes longitudinal movement of the second pusher member; and a drive member operably connected to the third rotatable shaft for transferring rotational motion from the third rotatable shaft to perform a third function; and an extension assembly including, at least one flexible band assembly operably connected to one of the first and second pusher assemblies.