Patent ID: 7588570

Claim:
A medical treatment instrument comprising a first conductor and a second conductor extending in parallel directions to each other and relatively shiftable in their axial directions, each conductor comprising an electrode located at a top end portion of the conductor, and a high-frequency voltage being applied to each top end portion of the conductors so as to coagulate and cut a biotissue held between the top end portion of the first conductor and the top end portion of the second conductor, wherein the top end portion of the first conductor and the top end portion of the second conductor are inclined in the same direction with respect to the axial directions of the conductors, such that when the conductors are relatively shifted in their axial direction the top end portions of the conductors come close to each other to grip biotissue therebetween, and when the conductors are further relatively shifted in their axial direction the top end portions of the conductors slide against the biotissue and the electrodes generate a frictional force to cut the biotissue, wherein the top end portion of the first conductor and the top end portion of the second conductor are curved in the same direction with respect to the axial directions of the conductors, and having curvature radii of the top end portion of the first conductor and the top end portion of the second conductor that are different and are set in such a manner that, when the conductors are relatively shifted in the axial directions, the curved surfaces of the top end portions of the conductors facing each other come in contact with each other along their respective curved surfaces, wherein one of the oppositely facing surfaces of the first conductor and the second conductor is formed with a recess portion extending along the inclined surface of the instant conductor, and the other surface is formed with a projection portion extending along the inclined surface of the instant conductor, and the recess portion and the projection portion face each other in the axial directions of the conductors to grip a biotissue therebetween, and wherein said medical treatment instrument further comprising a conductive outer conductor electrically connectable to a ground of a high-frequency power source, and coating the outside of the first conductor via an insulating layer, and arranged coaxially of the first conductor, wherein the second conductor is relatively shiftable in its axial direction with respect to the outer conductor while being in contact with the outer peripheral portion of the outer conductor.