Endoscopic vessel sealer and divider having a flexible articulating shaft

An electrosurgical instrument for treating tissue, comprising: a housing; an elongated shaft extending distally from the housing, the elongated shaft having an axis A-A defined therethrough; first and second jaw members attached to a distal end of the elongated shaft, each jaw member including an electrically conductive tissue contacting surface adapted to connect to a source of electrosurgical energy such that the electrically conductive tissue contacting surfaces are capable of conducting electrosurgical energy through tissue held therebetween; a drive rod extending at least partially through the elongated shaft, the drive rod operatively coupled to at least one of the first and second jaw members such that reciprocation of the drive rod in an axial direction with respect to the axis A-A induces the first and second jaw members to move between a first position in spaced relation to one another and a second position closer to one another for engaging tissue; a first actuator operatively coupled to the drive rod to induce reciprocation of the drive rod in the axial direction such that the first actuator is operable to move the first and second jaw members between the first and second positions; and a second actuator operatively coupled to the drive rod to induce reciprocation of the drive rod in the axial direction independently of the first actuator such that a separation distance between the jaw members may be adjusted.