High frequency incision tool for endoscope
A high-frequency incision tool for endoscope comprises a sheath inserted through and extracted from a treatment tool guide lumen of an endoscope; an operation unit connected to the rear of the sheath; a pair of electrode blades disposed in parallel and oriented forward at the front position of the sheath, the pair of electrode blades opening forward and closing back through remote manipulation of the operation unit; and a planar portion provided at the tip of at least one of the electrode blades, the planar portion having a projected area, when viewed from the front, larger than the cross sectional areas of the electrode blades at a portion close to their front ends.
1. A high-frequency incision tool for endoscope comprising:
a sheath inserted through and extracted from a treatment tool guide lumen of an endoscope;
an operation unit connected to a rear of the sheath;
a pair of electrode blades disposed in parallel and oriented forward at a front position of the sheath, the pair of electrode blades being adapted to open and close through remote manipulation of the operation unit; and
a planar portion provided at a tip of at least one of the electrode blades, the planar portion having a projected area, when viewed from the front, larger than a cross sectional area of the electrode blade at a portion close to a front end thereof,
wherein the planar portion is formed of an electrically insulating member which is attached to the most distal tip of the electrode blade and encloses the most distal tip of the electrode blade and wraps around a portion of at least one adjacent side of the electrode blade.
2. The high-frequency incision tool according to claim 1 , wherein the planar portion is formed so as to project sideways from the tip portion of the electrode blade.
3. The high-frequency incision tool according to claim 2 , wherein the tip of the electrode blade is formed so as to bend sideways to form an L-shape.
4. The high-frequency incision tool according to claim 2 , wherein each of the pair of electrode blades deviates sideways from extension of a center axis line of the front end portion of the sheath.
5. The high-frequency incision tool according to claim 2 , wherein the tip of the electrode blade is formed in a T-shape with a crossbar of the T projecting sideways in opposite directions.
6. The high-frequency incision tool according to claim 1 , wherein the electrically insulating member is attached to an outer surface of the electrode blade.
7. The high-frequency incision tool according to claim 6 , wherein the electrically insulating member is an adhesive adhered to an area extending from the tip to a back side of the electrode blade, the back side representing a side viewed in the open/close direction of the blades.
8. The high-frequency incision tool according to claim 1 , wherein the electrically insulating member is attached to the electrode blade, sandwiches the electrode blade and connects to the electrode blade through a hole drilled through the electrode blade to form an integral part.
9. The high-frequency incision tool according to claim 1 , wherein saw teeth having successive projections and recesses are formed on opposite sides of the pair of electrode blades, and an apex of an individual saw tooth projects toward the closing direction beyond the electrically insulating member attached to the electrode blade.
10. The high-frequency incision tool according to claim 1 , wherein the pair of electrode blades is biased in the opening direction and opened and closed by advancing and retracting the electrode blades out of or into the front end of the sheath with an operation wire inserted through the sheath.
11. The high-frequency incision tool according to claim 1 , wherein the pair of the electrode blades is opened and closed around a shaft disposed in the front end portion of the sheath and an operation wire for driving the pair of the electrode blades is inserted through the sheath.
12. The high-frequency incision tool according to claim 11 , wherein the operation wire is formed of a conductive member through which a high-frequency current is applied to the electrode blades.
13. The high-frequency incision tool according to claim 1 , wherein each of the pair of the electrode blades is formed into a shape in which a cup of bawl-shaped biopsy forceps is cut in half.
14. The high-frequency incision tool according to claim 1 , wherein a casing tube fits around the sheath throughout its length and the sheath and the electrode blades can freely rotate around an axis of the casing tube relative to the casing tube.
15. The high-frequency incision tool according to claim 14 , wherein the operation unit can rotate the sheath and the electrode blades relative to the casing tube.
16. The high-frequency incision tool according to claim 14 , wherein the sheath is formed of a close-wound metal coil and the casing tube is formed of an electrically insulating tube.