A surgical apparatus includes a housing that supports a shaft assembly. The shaft assembly defines a longitudinal axis therethrough and includes coaxially aligned outer and inner shaft members. The inner shaft member is movable within the outer shaft member. An end effector includes a pair of jaw members disposed at a distal end of the outer shaft. At least one of the jaw members is pivotably coupled to the outer shaft and is movable between open and clamping configurations for grasping tissue. The inner shaft contacts a proximal end of the moveable jaw member to maintain the movable jaw member in the open configuration and is slidable against the movable jaw member to move the moveable jaw member between the open configuration and clamping configuration.
