A surgical instrument, comprising: a housing including an elongated shaft having a distal portion and a proximal portion coupled to the housing, the elongated shaft defining a longitudinal axis; an inner shaft member extending at least partially through the elongated shaft, the inner shaft member selectively movable in a longitudinal direction with respect to the elongated shaft; 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 pivotally coupled to the distal portion of the elongated shaft about a pivot axis and including a first pair of laterally spaced flanges (450a,450b); and a lower jaw member pivotally coupled to the distal portion of the elongated shaft about the pivot axis and including a second pair of laterally spaced flanges (452a,452b), wherein the first and second pairs of flanges of the jaw members (450, 452) 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, characterized in that the surgical instrument further comprises a knife selectively movable in a longitudinal direction with respect to the inner shaft member, and the inner shaft member includes a knife guide disposed on a distal end of the inner shaft member. a housing including an elongated shaft having a distal portion and a proximal portion coupled to the housing, the elongated shaft defining a longitudinal axis; an inner shaft member extending at least partially through the elongated shaft, the inner shaft member selectively movable in a longitudinal direction with respect to the elongated shaft; 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 pivotally coupled to the distal portion of the elongated shaft about a pivot axis and including a first pair of laterally spaced flanges (450a,450b); and a lower jaw member pivotally coupled to the distal portion of the elongated shaft about the pivot axis and including a second pair of laterally spaced flanges (452a,452b), wherein the first and second pairs of flanges of the jaw members (450, 452) 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, an upper jaw member pivotally coupled to the distal portion of the elongated shaft about a pivot axis and including a first pair of laterally spaced flanges (450a,450b); and a lower jaw member pivotally coupled to the distal portion of the elongated shaft about the pivot axis and including a second pair of laterally spaced flanges (452a,452b), wherein the first and second pairs of flanges of the jaw members (450, 452) 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,