| 摘要 |
PURPOSE: To make an ablation instrument usable in fine, accurate excision by causing an inner needle to exhibit a radial force to the inside of an outer needle during the reciprocating movement of the inner needle. CONSTITUTION: An outer needle 70 is swaged and set into the diameter of a controlled inner needle 20, and the outside diameter of the inner needle 20 is made larger than the swaged bore 73 of the outer needle 70. Thus the inner needle 20 is placed within the outer needle 70 while in an interference fit in the swaged area, while clearance related to the remaining length of its part inserted into the needle 70 is maintained. Therefore when the inner needle 20 makes a reciprocating movement inside the outer needle 70, a radial force like that of a spring exists on the inner needle 20 at the point of contact with the outer needle 70. Thereby a large and accurate shearing force for tissue to be excised is produced, and the tissue is subjected to easy ablation while adverse effects such as tissue damage are minimized. |
