主权项 |
1. A high-frequency knife comprising:
a sheath having a flexibility and in which a conduit line that is communicated with a fluid source supplying a fluid is formed; a supporting member which is provided on an inner peripheral surface of a distal end portion of the sheath and has electric insulation; and an electrode portion which has a rod-shaped electrode that is capable of advancing and retracting with respect to the supporting member, and a larger-diameter portion provided at a distal end of the rod-shaped electrode, an outer diameter of the larger-diameter portion being larger than that of the rod-shaped electrode, wherein the supporting member is formed with an opening hole which passes through the supporting member in an axial direction of the sheath, into which the rod-shaped electrode is inserted, and which communicates with the conduit line of the sheath, wherein a guide hole is formed in the larger-diameter portion so as to pass through from a proximal end of the larger-diameter portion to a distal end thereof, wherein the guide hole is located further toward a radial inner side than an outer edge of the opening of a distal end of the opening hole and further toward a radial outer side than the rod-shaped electrode and overlaps the opening of the distal end of the opening hole in the direction of a longitudinal axis of the rod-shaped electrode, wherein a distal end of the sheath extends further toward the distal end side than the supporting member, wherein the fluid that is supplied through the conduit from the fluid source is capable of flowing through a gap between an outer peripheral surface of the rod-shaped electrode and an inner peripheral surface of the opening hole, wherein the fluid is injected to a front of the larger-diameter portion through the guide hole by covering an edge of a proximal end surface of the larger-diameter portion with the radial outer side of the distal end portion and communicating with the opening hole and the guide hole in a pull-back state where the electrode portion is pulled back toward a proximal end portion of the sheath. |