Treatment instrument

1. A treatment instrument comprising:

a longitudinal-axis member that is tubular and is provided so as to extend along a longitudinal axis;

a collecting member that is provided at a distal end of the longitudinal-axis member, the collecting member having an opening portion for introducing a tissue and a containing portion which includes an internal space for containing the tissue and which communicates with the opening portion;

a frame part that is provided along an edge of the opening portion in order to define a shape of the opening portion;

an opening-closing portion that is fixed to a distal end portion of the frame part;

an opening operating member that is connected to a proximal end portion of the frame part and is provided so as to be capable of moving inside the longitudinal-axis member along the longitudinal axis;

a curved portion that has a first end portion fixed to the distal end portion of the frame part and a second end portion connected to the first end portion and provided to extend toward the proximal end portion of the frame part, the curved portion being formed in a curved shape through a deepest portion of the containing portion from the first end portion to the second end portion; and

a volume operating member that is connected to the second end portion of the curved portion; wherein

the containing portion includes a tunnel portion that has a through hole through which a part of the curved portion is configured to advance and retract;

when the opening operating member is operated such that the opening portion defined by the frame part is opened, the volume operating member causes the curved portion to move toward a proximal end side of the longitudinal-axis member such that the containing portion is deformed in a direction approaching an opening of the opening portion, and

the opening portion of the collecting member is closed by rotating around the opening-closing portion as a rotation center.

2. The treatment instrument according to claim 1 , wherein the tunnel portion is provided in the deepest portion of the containing portion.

3. The treatment instrument according to claim 1 , wherein

the curved portion is a volume adjusting member that has a portion passing through the deepest portion of the containing portion, is formed in the curved shape through the deepest portion of the containing portion, and adjusts a volume of the containing portion,

the volume operating member is provided so as to be movable along the longitudinal axis with respect to the opening operating member, and

an operation portion allows the opening operating member and the volume operating member to be advanced and retracted in the direction of the longitudinal axis independently from each other.

4. The treatment instrument according to claim 1 , wherein

the curved portion is a volume adjusting member that has a portion passing through the deepest portion of the containing portion, is formed in the curved shape through the deepest portion of the containing portion, and adjusts a volume of the containing portion,

the volume operating member is provided so as to be movable along the longitudinal axis with respect to the opening operating member, and

(i) a depth of the containing portion when being measured in a direction intersecting an opening surface defined by the edge of the opening portion, and (ii) an opening area of the opening portion are each adjusted independently from each other by advancing and retracting the opening operating member and the volume operating member, respectively, independently from each other in the direction of the longitudinal axis.

5. The treatment instrument according to claim 4 , wherein the treatment instrument has a state where the opening portion is closed when the depth of the containing portion is maintained.

6. The treatment instrument according to claim 1 , wherein

the curved portion is a volume adjusting member that has a portion passing through the deepest portion of the containing portion, is formed in the curved shape through the deepest portion of the containing portion, and adjusts a volume of the containing portion,

the volume operating member that is is provided so as to be movable along the longitudinal axis with respect to the opening operating member, and

the treatment instrument has:

a state where a position of the opening operating member with respect to the longitudinal-axis member is fixed and the volume operating member is advanced and retracted with respect to the longitudinal-axis member, such that the volume of the containing portion varies while the opening area of the opening portion is maintained at a predetermined opening area, and

a state where the position of the volume operating member with respect to the longitudinal-axis member is fixed and the opening operating member is advanced and retracted with respect to the longitudinal-axis member, such that the opening area of the opening portion varies while the depth of the containing portion is maintained.

7. The treatment instrument according to claim 6 , wherein the treatment instrument has a state where the opening portion is closed when the depth of the containing portion is maintained.

8. The treatment instrument according to claim 5 , wherein the longitudinal-axis member is a flexible structure.

9. The treatment instrument according to claim 7 , wherein the longitudinal-axis member is a flexible structure.

10. The treatment instrument according to claim 1 , wherein

a pair of rigid portions are disposed on the opening-closing portion, each of the pair of rigid portions being formed in a rod shape, and each of the pair of rigid portions being configured to cover the distal end portion of the frame part; and

a proximal end of each of the pair of rigid portions is configured to open and close by rotating around a distal end of each of the pair of rigid portions to open and close the opening portion of the collecting member.