Endoscopic surgery device, method of inserting endoscope and treatment tool, and method of removing endoscope and treatment tool

1. An endoscopic surgery device comprising:

an endoscope which includes a linear insertion part and includes an imaging sensor configured to observe a body cavity;

a treatment tool including a linear insertion part having a proximal end provided with an operation part; and

an outer tube which is configured to allow each of the insertion part of the endoscope and the insertion part of the treatment tool to be movable back and forth, wherein the insertion part of the endoscope and the insertion part of the treatment tool are coupled with each other by a coupling part that is arranged inside the outer tube, the insertion part of the endoscope and the insertion part of the treatment tool are in a coupled state so as to move in an axial direction of the outer tube with an allowance amount, when either one of the insertion part of the endoscope and the insertion part of the treatment tool move back and forth within the allowance amount, then another one of the insertion part of the endoscope and the insertion part of the treatment tool does not move back and forth, and when either one of the insertion part of the endoscope and the insertion part of the treatment tool move back and forth beyond the allowance amount, then another one of the insertion part of the endoscope and the insertion part of the treatment tool will move back and forth,

wherein the endoscopic surgery device satisfies expressions of Lt≤Ls<Lh, and Lh≥Ls1+Ls+t, where

Lt (mm) is a length of the outer tube, Ls (mm) is a length of a hard part of the insertion part of the endoscope, Lh (mm) is a length of a hard part of the insertion part of the treatment tool, Ls1 (mm) is a minimum projection length of a distal end of the insertion part of the treatment tool with respect to a distal end of the insertion part of the endoscope, and t (mm) is the allowance amount of the insertion part of the treatment tool with respect to the insertion part of the endoscope,

wherein the endoscopic surgery device further comprises:

a coupling member constituting the coupling part that is arranged inside the outer tube and is configured to couple the insertion part of the endoscope to the insertion part of the treatment tool to allow the insertion part of the treatment tool to move in an axial direction of the outer tube with the allowance amount with respect to the insertion part of the endoscope,

wherein the coupling member includes:

a first movable object which is configured to be movable in the axial direction of the outer tube and hold the insertion part of the endoscope inserted into the outer tube; and

a second movable object which is provided in the first movable object, configured to hold the insertion part of the treatment tool inserted into the outer tube, and move in the axial direction of the outer tube by the allowance amount with respect to the first movable object.

2. The endoscopic surgery device according to claim 1 , wherein the minimum projection length Ls1 satisfies Ls1≥0.

3. The endoscopic surgery device according to claim 2 , wherein the minimum projection length Ls1 is a length with which at least the distal end of the insertion part of the treatment tool is positioned in an observation field of view of the endoscope.

4. The endoscopic surgery device according to claim 1 , wherein a distance between centers of the insertion part of the endoscope and the insertion part of the treatment tool in the outer tube is set shorter than a distance between an axial center of the insertion part of the treatment tool and at least a part of the operation part of the treatment tool.

5. The endoscopic surgery device according to claim 1 , wherein the distal end of the insertion part of the treatment tool has a treatment part, and the operation part of the treatment tool is a handle part configured to operate the treatment part.

6. The endoscopic surgery device according to claim 1 , wherein a flexible cable is coupled to a proximal end of the insertion part of the endoscope.

7. The endoscopic surgery device according to claim 1 , wherein the distal end of the insertion part of the endoscope has the image sensor.

8. The endoscopic surgery device according to claim 1 , wherein

the first movable object is engaged with the outer tube with a first frictional force, and

the second movable object is engaged with the insertion part of the treatment tool with a second frictional force greater than the first frictional force, engaged with the first movable object with a third frictional force less than the first frictional force, and slides against the first movable object by the allowance amount.

9. A method of inserting the endoscope and the treatment tool into the outer tube by using the endoscopic surgery device according to claim 1 , the method comprising:

a first insertion step of inserting the insertion part of the endoscope into the outer tube; and

a second insertion step of inserting the insertion part of the treatment tool into the outer tube into which the insertion part of the endoscope has been inserted.

10. A method of removing the endoscope and the treatment tool from the outer tube by using the endoscopic surgery device according to claim 1 , the method comprising:

a first removal step of removing the insertion part of the treatment tool from the outer tube; and

a second removal step of removing the insertion part of the endoscope from the outer tube from which the insertion part of the treatment tool has been removed.