Puncture needle
A puncture needle includes: an outer needle including a lumen extending in an axial direction; an outer needle hub joined to a proximal end portion of the outer needle; an inner needle located in the lumen of the outer needle; a switching mechanism configured to switch between a first state in which a needle tip of the puncture needle is sharp and a second state in which the needle tip of the puncture needle is blunt by displacing the inner needle in the axial direction; and a lock mechanism that maintains a position of the inner needle.
1 . A puncture needle comprising:
an outer needle including a lumen extending in an axial direction;
an outer needle hub joined to a proximal end portion of the outer needle;
an inner needle located in the lumen of the outer needle;
an inner needle hub located at a proximal end of the inner needle inside the outer needle hub; and
a switching mechanism configured to switch between a first state in which a needle tip of the puncture needle is sharp and a second state in which the needle tip of the puncture needle is blunt by displacing the inner needle in the axial direction, wherein the switching mechanism comprises:
a guide groove that is located in the outer needle hub and is configured to guide the inner needle hub in the axial direction,
a recess that is located in the guide groove and is configured to position the inner needle hub at a first position, and
a stopper projection located on the inner needle hub, protruding from the inner needle hub toward the guide groove while being elastically biased, and configured to engage with the recess.
2 . The puncture needle according to claim 1 , wherein a distal end of the inner needle is sharp, and a distal end of the outer needle is blunt.
3 . The puncture needle according to claim 2 , wherein:
the recess is a first recess, and
the switching mechanism further comprises a second recess that is located on a proximal end side of the first recess and is configured to position the inner needle hub at a second position, and
the stopper projection is configured to engage with the first recess and the second recess.
4 . The puncture needle according to claim 1 , wherein a distal end of the outer needle is sharp, and a distal end of the inner needle is blunt.
5 . The puncture needle according to claim 4 , wherein a backcut portion is formed at the distal end of the outer needle.
6 . The puncture needle according to claim 5 , wherein:
the recess is a first recess, and
the switching mechanism further comprises a second recess that is located on a proximal end side of the first recess and is configured to position the inner needle hub at a second position, and
the stopper projection is configured to engage with the first recess and the second recess.
7 . The puncture needle according to claim 4 , wherein:
the recess is a first recess, and
wherein the switching mechanism further comprises and a second recess that is located on a proximal end side of the first recess and is configured to position the inner needle hub at a second position, and
the stopper projection is configured to engage with the first recess and the second recess.
8 . The puncture needle according to claim 1 , wherein:
the recess is a first recess, and
the switching mechanism further comprises a second recess that is located on a proximal end side of the first recess and is configured to position the inner needle hub at a second position, and
the stopper projection is configured to engage with the first recess and the second recess.
9 . The puncture needle according to claim 8 , wherein the inner needle hub comprises a slider configured to release engagement between the stopper projection and the first recess or the second recess by pulling the stopper projection inward.
10 . The puncture needle according to claim 8 , wherein the first recess and the second recess comprise a step portion configured to prevent detachment of the stopper projection.
11 . The puncture needle according to claim 8 , wherein the guide groove comprises an inclined surface configured to guide the stopper projection to the first recess or the second recess.
12 . A method of operating a puncture needle, the method comprising:
providing the puncture needle, which comprises:
an outer needle including a lumen extending in an axial direction, wherein a distal end of the outer needle is blunt,
an outer needle hub joined to a proximal end portion of the outer needle,
an inner needle located in the lumen of the outer needle, wherein a distal end of the inner needle is sharp,
an inner needle hub located at a proximal end of the inner needle inside the outer needle hub, and
a switching mechanism comprising:
a guide groove that is located in the outer needle hub and is configured to guide the inner needle hub in the axial direction,
a recess that is located in the guide groove and is configured to position the inner needle hub at a first position, and
a stopper projection located on the inner needle hub, protruding from the inner needle hub toward the guide groove while being elastically biased, and configured to engage with the recess,
protruding a distal end portion of the inner needle from a distal end portion of the outer needle such that the guide groove guides the inner needle hub to the first position at which the stopper projection engages with the recess;
while the distal end portion of the inner needle is located distal of the distal end portion of the outer needle, puncturing skin of a patient with the sharp distal end of the inner needle;
operating the switching mechanism to pull the distal end portion of the inner needle in an axial direction to a position proximal of the distal end portion of the outer needle; and
advancing the puncture needle to a target site of the living tissue.
13 . A method of operating a puncture needle, the method comprising:
providing the puncture needle, which comprises:
an outer needle including a lumen extending in an axial direction, wherein a distal end of the outer needle is sharp,
an outer needle hub joined to a proximal end portion of the outer needle,
an inner needle located in the lumen of the outer needle, wherein a distal end of the inner needle is blunt,
an inner needle hub located at a proximal end of the inner needle inside the outer needle hub, and
a switching mechanism comprising:
a guide groove that is located in the outer needle hub and is configured to guide the inner needle hub in the axial direction,
a recess that is located in the guide groove and is configured to position the inner needle hub at a first position, and
a stopper projection located on the inner needle hub, protruding from the inner needle hub toward the guide groove while being elastically biased, and configured to engage with the recess,
protruding a distal end portion of the outer needle from a distal end portion of the inner needle such that the guide groove guides the inner needle hub to the first position at which the stopper projection engages with the recess;
while the distal end portion of the outer needle is located distal of the distal end portion of the inner needle, puncturing skin of a patient with the sharp distal end of the outer needle;
operating the switching mechanism to pull the distal end portion of the outer in an axial direction to a position proximal of the distal end portion of the inner needle; and
advancing the puncture needle to a target site of the living tissue.