A surgical instrument, comprising: a housing; an elongated shaft including a proximal portion coupled to the housing and a distal portion opposite the proximal portion, the elongated shaft defining a longitudinal axis; a drive rod extending at least partially through the elongated shaft, the drive rod selectively movable in a longitudinal direction with respect to the elongated shaft; a cam pin supported by the drive rod such that longitudinal movement of the drive rod is imparted to the cam pin, and an end effector supported by the distal portion of the elongated shaft, the end effector adapted for treating tissue and comprising: an upper jaw member (150,222) pivotally coupled to the distal portion of the elongated shaft about a pivot axis and including a first pair of laterally spaced flanges(150a,150b) each defining a camming slot for engaging the cam pin; and a lower jaw member (152,224) pivotally coupled to the distal portion of the elongated shaft about the pivot axis and including a second pair of laterally spaced flanges (152a,152b) each defining a camming slot for engaging the cam pin, characterized in that: the first and second pairs of flanges of the jaw members are arranged in an offset configuration such that one flange of the upper jaw member is positioned on a laterally exterior side of a corresponding flange of the lower jaw member, and the other flange of the upper jaw member is positioned on a laterally interior side of the other flange of the lower jaw member; the drive rod exhibits a generally u-shaped profile; and the surgical instrument further comprises a knife selectively movable in a longitudinal direction with respect to the drive rod, the knife supported within the u-shaped profile such that the drive rod restricts lateral movement of the knife in a first lateral plane. a housing; an elongated shaft including a proximal portion coupled to the housing and a distal portion opposite the proximal portion, the elongated shaft defining a longitudinal axis; a drive rod extending at least partially through the elongated shaft, the drive rod selectively movable in a longitudinal direction with respect to the elongated shaft; a cam pin supported by the drive rod such that longitudinal movement of the drive rod is imparted to the cam pin, and an end effector supported by the distal portion of the elongated shaft, the end effector adapted for treating tissue and comprising: an upper jaw member (150,222) pivotally coupled to the distal portion of the elongated shaft about a pivot axis and including a first pair of laterally spaced flanges(150a,150b) each defining a camming slot for engaging the cam pin; and a lower jaw member (152,224) pivotally coupled to the distal portion of the elongated shaft about the pivot axis and including a second pair of laterally spaced flanges (152a,152b) each defining a camming slot for engaging the cam pin, an upper jaw member (150,222) pivotally coupled to the distal portion of the elongated shaft about a pivot axis and including a first pair of laterally spaced flanges(150a,150b) each defining a camming slot for engaging the cam pin; and a lower jaw member (152,224) pivotally coupled to the distal portion of the elongated shaft about the pivot axis and including a second pair of laterally spaced flanges (152a,152b) each defining a camming slot for engaging the cam pin, the first and second pairs of flanges of the jaw members are arranged in an offset configuration such that one flange of the upper jaw member is positioned on a laterally exterior side of a corresponding flange of the lower jaw member, and the other flange of the upper jaw member is positioned on a laterally interior side of the other flange of the lower jaw member; the drive rod exhibits a generally u-shaped profile; and the surgical instrument further comprises a knife selectively movable in a longitudinal direction with respect to the drive rod, the knife supported within the u-shaped profile such that the drive rod restricts lateral movement of the knife in a first lateral plane.