SURGICAL INSTRUMENT
To achieve improvement in terms of a burden on an operator when performing position adjustment for determining a target position of treatment in surgery without increasing the size of a surgical instrument. The surgical instrument includes a main body, a mover, and a fixer. The main body has a first male screw on an outer circumferential surface and a second female screw on an inner circumferential surface. The mover has a position indicator indicating a position and a first female screw with which the first male screw is screwed. The fixer has a second male screw that is screwed with the second female screw. The first male screw and the second male screw are in a reverse-thread screw relationship.
1 . A surgical instrument, comprising:
a main body comprising a first male screw on an outer circumferential surface of a cylinder and a second female screw on an inner circumferential surface of the cylinder;
a mover comprising a position indicator that indicates a target position and a first female screw screwed with the first male screw; and
a fixer comprising a second male screw screwed with the second female screw, wherein
rotation of the mover in a rotation direction of the first male screw is restricted, and the first male screw and the second male screw are in a reverse-thread screw relationship.
2 . The surgical instrument according to claim 1 , wherein the mover is movably disposed on an outer surface of the fixer.
3 . The surgical instrument according to claim 1 , wherein the position indicator is a guide that indicates a cutting position of a bone as the target position.
4 . The surgical instrument according to claim 3 , wherein the cutting position of the bone is a cutting position at a proximal end of a tibial bone.
5 . The surgical instrument according to claim 3 , wherein the guide comprises at least one slit.
6 . The surgical instrument according to claim 3 , wherein the fixer is fixable to a separate instrument fixed to the bone.
7 . The surgical instrument according to claim 1 , wherein a screw thread of the first male screw is provided to make the mover move away from the main body when the main body is rotated clockwise as viewed from a side opposite to a side where the fixer is screwed.
8 . The surgical instrument according to claim 1 , wherein an amount of advancement as a result of rotating the second male screw once is smaller than an amount of advancement as a result of rotating the first male screw once.
9 . The surgical instrument according to claim 1 further comprising an operation inputter provided at one end portion of the main body and being capable of rotating the main body, wherein
a diameter of the operation inputter is larger than a diameter of the main body.
10 . The surgical instrument according to claim 1 , wherein the first male screw and/or the second male screw is a multi-start screw.