Medical instrument for endoscope

1. A medical treatment instrument for an endoscope comprising:

an insulated sheath;

a treatment member provided at a distal end of the sheath;

a wire loop that surrounds and wraps around a tip of the treatment member, the wire loop being configured for expansion and contraction by an operation at a proximal side of the sheath; and

a pair of through holes formed on a side wall of the sheath, the pair of through holes extending transversely through the side wall in a vicinity of the distal end of the sheath, and a wire of the wire loop moving in and out through the through holes so that the wire loop is expanded and contracted.

2. The medical treatment instrument according to claim 1 , wherein the sheath is configured to be inserted into and removed from a medical instrument insert channel of the endoscope.

3. The medical treatment instrument according to claim 1 , wherein the wire loop is configured to receive high-frequency current, the wire loop being insulated from the electrode.

4. A medical treatment instrument for an endoscope comprising:

an insulated sheath;

a treatment member provided at a distal end of the sheath;

a wire loop that surrounds and wraps around a tip of the treatment member, the wire loop being configured for expansion and contraction by an operation wire provided at a proximal side of the sheath; and

the treatment member including an electrode configured to receive high-frequency current,

the wire loop being insulated from the electrode.

5. The medical treatment instrument according to claim 4 , further comprising a conductive wire electrically connected to the electrode at a center axis of the sheath, and the operation wire configured to be operated from the sheath side so as to cause expansion and contraction of the wire loop, the operation wire being inserted into and disposed in the sheath alongside of the conductive wire so as to be capable of moving in the fore-and-back direction.

6. The medical treatment instrument according to claim 4 , wherein a portion of the electrode projecting from the distal end of the sheath is configured to have a plate shape, and a surface of the projecting plate-shaped portion and the wire loop are substantially flush with each other.

7. The medical treatment instrument according to claim 4 , wherein an amount of projection of the electrodes, projecting forwardly from the distal end of the sheath, is configured to be adjusted by an operation at the proximal side of the sheath.

8. The medical treatment instrument according to claim 7 , wherein the electrode is configured to project from and retract into the sheath.

9. The medical treatment instrument according to claim 4 , wherein the electrode includes a pair of beak-shaped electrodes which open and close by remote control at the proximal side of the sheath, and

wherein the wire loop surrounds a front space opposite the pair of beak-shaped electrodes, the wire loop being configured to expand and contract independently of the opening and closing of the pair of beak-shaped electrodes.

10. The medical treatment instrument according to claim 9 , wherein through holes are provided through the pair of beak-shaped electrodes so as to penetrate therethrough in the opening and closing direction thereof, so that proximal portions of a wire of the wire loop are led through an inner side of the pair of beak-shaped electrodes from the through holes into the sheath, respectively.