Surgical instrument

Abstract

To provide a surgical instrument that can be easily attached to and detached from a pedicle screw.SOLUTION: A surgical instrument includes: an outer part including a contact part capable of contacting a rod; and an inner part including a plurality of grip pieces, and including, in a first end, a grip part that grips a head part of a pedicle screw. At least any of corners in the first end side of the grip pieces includes a cutoff part that is cut off diagonally with respect to a longitudinal direction.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present disclosure relates to a surgical instrument for adjusting the position of a rod used in spinal fixation surgery.

Background Art

[0002] Spinal fixation surgery for fixing a plurality of vertebrae to each other is known. In spinal fixation surgery, as an example, a rod is passed between pedicle screws inserted into the pedicles of the vertebrae to fix the vertebrae.

[0003] In order to fix the vertebrae at an accurate position, it is necessary to make the position of the rod passed through the pedicle screws accurate. Therefore, surgical instruments for adjusting the position of the rod, such as a rod positioner and a rod reducer, are known.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] A surgical instrument for adjusting the position of a rod is attached to a pedicle screw to adjust the position of the rod. Therefore, it is preferable that the surgical instrument can be easily attached to the pedicle screw and easily removed from the pedicle screw.

Means for Solving the Problems

[0006] A surgical instrument according to one aspect of the present disclosure includes an inner part and an outer part positioned to cover the inner part and movable in the longitudinal direction of the inner part. The outer part has a contact part that can contact a rod. The inner part includes a plurality of gripping pieces and has a gripping part at a first end for gripping the head part of a pedicle screw. At least one of the corners on the first end side of the gripping piece has a cut-off part that is cut off obliquely with respect to the longitudinal direction.

Advantages of the Invention

[0007] According to one aspect of the present disclosure, a surgeon can easily attach the surgical instrument to a pedicle screw.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Embodiments for Carrying Out the Invention

[0009] Hereinafter, an embodiment of the present disclosure will be described in detail. First, with reference to FIG. 1, an overview of the surgical instrument 1 according to this embodiment will be described. FIG. 1 is a diagram showing an overall outline of the surgical instrument 1. The surgical instrument 1 is an instrument for adjusting the position of the spine and is generally an instrument for adjusting the position of a rod, such as a rod positioner, a rod reducer, etc.

[0010] As shown in FIG. 1, the surgical instrument 1 includes a handle portion 10 and a main body portion 20. By operating the handle portion 10, the main body portion 20 operates to adjust the positional relationship between the pedicle screw 100 and the rod 110. By adjusting the positional relationship between the pedicle screw 100 and the rod 110, the position of the vertebra 120 into which the pedicle screw 100 is inserted can be adjusted along the axis of the rod 110.

[0011] FIG. 2 shows the details of the main body portion 20 of the surgical instrument 1. As shown in FIG. 2, the main body portion 20 includes an outer portion 21 and an inner portion 22. 201 in FIG. 2 indicates the outer portion 21. 202 in FIG. 2 indicates the inner portion 22. Further, 203 in FIG. 2 shows a state in which the outer portion 21 is arranged to cover the inner portion 22. The surgical instrument 1 is used in a state where the outer portion 21 is arranged to cover the inner portion 22 as shown in 203 of FIG. 2.

[0012] As shown in FIG. 2, both the outer portion 21 and the inner portion 22 are substantially cylindrical (substantially cylindrical shape), and the outer portion 21 is positioned so as to cover the inner portion 22. Since the inner portion 22 and the outer portion 21 are substantially cylindrical, they are movable relative to each other in the axial direction of the cylinder. That is, the outer portion 21 is movable axially with respect to the inner portion 22, and the inner portion 22 is movable axially with respect to the outer portion 21. The axial direction of the cylinder can also be referred to as the longitudinal direction of the cylinder. The substantially cylindrical (substantially cylindrical shape) is a shape that is not a complete cylindrical shape and includes, in a part of the cylinder, (1) a cross-sectional shape different from other parts, (2) a cross-sectional area different from other parts, (3) a part of the side surface of the cylinder being missing, and the like.

[0013] The relative movement between the outer portion 21 and the inner portion 22 can be achieved by operating the handle portion 10. Specifically, when the operator grasps the handle portion 10, the outer portion 21 moves along the axis to the side opposite to the handle portion 10 with respect to the inner portion 22. Further, when the outer portion 21 and the inner portion 22 rotate about the axis, they rotate integrally.

[0014] The outer part 21 has a contact part 211 that can contact the rod 110 at the end that becomes the rod side during use. The contact part 211 has a concave shape with an arc-shaped recess such that the part contacting the rod 110 follows the outer circumference of the rod 110.

[0015] Among both ends of the inner part 22, when the end that becomes the pedicle screw 100 side during use is defined as the first end and the end opposite to the first end is defined as the second end, the inner part 22 has a gripping part 221 that grips the pedicle screw 100 at the first end.

[0016] FIG. 3 shows the details of the gripping part 221. 301 in FIG. 3 is a view seen from a direction perpendicular to the axis of the inner part 22. 302 in FIG. 3 is a view seen obliquely from the first end side of the inner part 22.

[0017] As shown in 302 of FIG. 3, the gripping part 221 is composed of a pair of gripping pieces 222. At the first end of the inner part 22, two cuts 227 are provided in the axial direction. The gripping pieces 222 are formed on the first end side of the side wall of the inner part 22 other than the cuts 227 so as to face each other with respect to the axis center. The outer surface of the gripping pieces 222 protrudes in the outer direction more than other parts of the inner part 22. Also, as shown in 301 of FIG. 3, holes 224 are provided in the gripping pieces 222. The corner at the first end side of the gripping pieces 222 is a cut-off part 223 that is cut off obliquely with respect to the axial direction. The cuts 227 are connected to a slit 226 described later. Thereby, when a force is applied to the gripping pieces 222 in the outer direction, that is, the direction in which the diameter of the inner part 22 expands, a biasing force in the direction opposite to the force can be obtained. In other words, the gripping pieces 222 can be given a function as a leaf spring.

[0018] In FIG. 3, a pair of opposing gripping pieces 222 are shown. By providing a pair of opposing gripping pieces 222, the head portion 105 of the pedicle screw 100 can be easily gripped. The gripping pieces 222 are not limited to a pair (two), and may be three or more. And the corner on the first end side of the gripping piece 222 is a cut-off portion 223 that is cut off obliquely with respect to the axial direction. The cut-off portion 223 may be cut off linearly. The cut-off portion 223 may be cut off in a convex curved shape on the outside. In FIG. 3, cut-off portions 223 are provided at both corners on the first end side of the gripping piece 222. The cut-off portion 223 may be provided only at one corner on the first end side of the gripping piece 222.

[0019] Further, the gripping piece 222 is provided with a hole 224 into which a protrusion of the head portion of the pedicle screw 100 is locked. And the opening of the hole 224 is substantially elliptical. Since the hole 224 locks the protrusion 101 (see FIG. 4) of the head portion 105 (see FIG. 4) of the pedicle screw 100, it can also be called a locking portion. When the protrusion 101 of the pedicle screw 100 is locked in the hole 224, the possibility that the surgical instrument 1 including the inner portion 22 moves in a direction away from the pedicle screw 100 can be reduced. Also, by making the opening substantially elliptical, the pedicle screw 100 can be made difficult to move in the axial direction of the surgical instrument 1 and can be easily disengaged in the circumferential direction.

[0020] Also, as shown at 302 in FIG. 3, the inner surface of the gripping piece 222 has a tapered shape 225 in which the inner diameter of the cross section perpendicular to the axial direction becomes smaller as it moves away from the first end in the axial direction. Thereby, even if the axial positions of the surgical instrument 1 and the pedicle screw 100 are displaced, the surgical instrument 1 and the pedicle screw 100 can be easily engaged.

[0021] Here, the structure of the surgical instrument in the prior art will be described. 303 and 304 in FIG. 3 show the gripping portion 5221 of the surgical instrument in the prior art. 303 in FIG. 3 is a view of the inner portion of the surgical instrument in the prior art seen from a direction perpendicular to the axis. 304 in FIG. 3 is a view of the inner portion obliquely seen from the first end side.

[0022] In the gripping portion 5221 of the prior art, unlike the gripping portion 221 according to the present disclosure, the corner on the first end side of the gripping piece 5222 is not cut off obliquely with respect to the axial direction, and no cut-off portion is provided. Further, the shape of the hole 5224 provided in the gripping piece 5222 is substantially rectangular. Furthermore, the inner surface of the gripping piece 5222 is not tapered.

[0023] Thus, in the surgical instrument 1 according to the present disclosure and the surgical instrument in the prior art, for example, the presence or absence of the cut-off portion 223, the shape of the opening of the hole 224, and the structure of the inner surface of the gripping portion 221 are different.

[0024] Next, with reference to FIG. 4, a method of gripping the pedicle screw 100 with the gripping portion 221 of the inner portion 22 will be described. FIG. 4 is a view showing a state of gripping the pedicle screw 100 with the gripping portion 221 of the inner portion 22.

[0025] As shown in FIG. 4, a slit 226 is provided in the inner portion 22 in the axial direction. The slit 226 is connected to a notch 227 provided between the gripping pieces 222 of the gripping portion 221. Therefore, when a force is applied to the gripping piece 222 from the inside to the outside of the cylinder, the gripping piece 222 expands outward while being biased inward. In other words, the gripping piece 222 has a function as a leaf spring.

[0026] The diameter of the outer periphery of the head portion 105 of the pedicle screw 100 is substantially the same as the diameter of the inner periphery of the gripping piece 222 of the gripping portion 221. Therefore, when the gripping portion 221 is moved in the direction of the pedicle screw 100, the head portion 105 of the pedicle screw 100 overlaps with the inner peripheral surface of the gripping portion 221. As the gripping portion 221 continues to move, since the tapered shape 225 is formed on the inner surface of the gripping piece 222, the gripping piece 222 wraps around the head portion 105 of the pedicle screw 100 while being pushed outward of the cylinder. As the gripping portion 221 continues to move and the protrusion 101 of the head portion 105 of the pedicle screw 100 reaches the hole 224 of the gripping piece 222, since the gripping piece 222 is biased inward, the hole 224 of the gripping piece 222 and the protrusion 101 of the pedicle screw 100 engage with each other. As a result, the inner portion 22 and the pedicle screw 100 engage with each other, and the inner portion 22 is fixed to the pedicle screw 100.

[0027] Next, with reference to FIG. 5, a method for adjusting the position of the rod 110 by the surgical instrument 1 will be described.

[0028] 501 in FIG. 5 shows a state where the rod 110 is located in the middle of the U-shaped groove 106 of the head portion 105 of the pedicle screw 100 and has not reached the bottom of the U-shaped groove 106. In this state, the head portion 105 of the pedicle screw 100 is gripped by the gripping portion 221 of the surgical instrument 1, and the hole 224 of the gripping piece 222 and the protrusion 101 of the pedicle screw 100 are engaged with each other. As a result, the inner portion 22 of the surgical instrument 1 and the pedicle screw 100 are in a state where they cannot move in the axial direction. While the operator operates the handle portion 10 in this state, the outer portion 21 moves in the direction of the pedicle screw 100 while the inner portion 22 and the pedicle screw 100 are fixed.

[0029] The outer part 21 is provided with a contact part 211. When the outer part 21 moves, the contact part 211 contacts the rod 110. If the operator continues to operate the handle part 10 in this state, since the inner part 22 and the pedicle screw 100 are fixed, the contact part 211 of the outer part 21 will push the rod 110 into the bottom of the U-shaped groove. As a result, as shown in 502 of FIG. 5, the position of the rod 110 can be adjusted so that the rod 110 is located at the bottom of the U-shaped groove 106 of the pedicle screw 100.

[0030] As shown in 501 of FIG. 5, the contact part 211 may be arranged between two opposing gripping pieces 222 of the gripping part 221. Also, the distance between the gripping pieces 222 of the gripping part 221 may be substantially the same as the diameter of the rod 110. Thus, even if the rod 110 is located in the middle of the U-shaped groove 106 of the pedicle screw 100 and is not arranged in the correct position, the rod 110 will be located between the gripping pieces 222, and the contact part 211 can easily contact the rod 110.

[0031] Also, as shown in 502 of FIG. 5, the cut-off part 223 is arranged on the second end side relative to the rod 110 when the rod 110 is in the correct position, that is, when it is arranged at the bottom of the U-shaped groove 106 of the pedicle screw 100. More specifically, it is arranged on the second end side relative to the central axis of the rod 110. As a result, when the surgical instrument 1 is rotated, the cut-off part 223 will ride on the rod 110, so the operator can easily remove the surgical instrument 1 from the pedicle screw 100. Also, if the cut-off part 223 is provided at both corners on the first end side of the gripping pieces 222, the operator can easily remove the surgical instrument 1 from the pedicle screw 100 no matter in which direction the surgical instrument 1 is rotated around the axis.

[0032] As described above, the surgical instrument 1 adjusts the position of the rod 110 by gripping the pedicle screw 100 with the gripping part 221 and moving the outer part 21 in the axial direction of the inner part 22 with the outer part 21 in contact with the rod 110.

[0033] Next, with reference to FIG. 6, the adjustment of the position of the rod 110 by the surgical instrument 1 and the removal of the surgical instrument 1 from the pedicle screw 100 will be described.

[0034] First, as shown in 601 of FIG. 6, with the rod 110 positioned in the middle of the U-shaped groove 106 of the head portion 105 of the pedicle screw 100, the inner portion 22 of the surgical instrument 1 is attached to the head portion 105 of the pedicle screw 100. In this state, when the handle portion 10 of the surgical instrument 1 is operated to move the outer portion 21 in the direction of the pedicle screw 100, as shown in 602 of FIG. 6, the contact portion 211 of the outer portion 21 contacts the rod 110.

[0035] Continuing to operate the handle portion 10 as it is, when the contact portion 211 of the outer portion 21 presses the rod 110, as shown in 603 of FIG. 6, the rod 110 is pushed to the bottom of the groove of the U-shaped groove 106 of the head portion 105 of the pedicle screw 100. Thus, the adjustment of the position of the rod 110 is completed.

[0036] Next, when removing the surgical instrument 1 from the pedicle screw 100, first, as shown in 604 of FIG. 6, the outer portion 21 of the surgical instrument 1 is moved in a direction away from the pedicle screw 100.

[0037] As it is, even if trying to pull out or move the inner portion 22 of the surgical instrument 1 in a direction away from the pedicle screw 100, it cannot be pulled out because the protrusion 101 of the pedicle screw 100 and the hole 224 of the gripping portion 221 are engaged. Therefore, when the surgical instrument 1 is rotated about its axis, as shown in 605 of FIG. 6, the cut-off portion 223 of the gripping portion 221 rides on the rod 110. As a result, the engagement between the protrusion 101 of the pedicle screw 100 and the hole 224 of the gripping portion 221 is released, and as shown in 606 of FIG. 6, the surgical instrument 1 can be moved in a direction away from the pedicle screw 100.

[0038] As described above, the surgical instrument 1 according to the present disclosure includes an outer portion 21 and an inner portion 22 each having a substantially cylindrical shape. The outer portion 21 is positioned to cover the inner portion 22 and is movable in the axial direction of the inner portion 22. And the gripping portion 221 provided at the first end of the inner portion 22 has a plurality of gripping pieces 222, and at least one of the corners on the first end side of the gripping piece 222 has a cut-off portion 223 that is cut off obliquely with respect to the axial direction.

[0039] Generally, when attaching the surgical instrument 1 to the pedicle screw 100, the surgical instrument 1 is moved toward the pedicle screw 100, and the surgical instrument 1 and the pedicle screw 100 are engaged and attached. Here, if the positions of the surgical instrument 1 and the pedicle screw 100 are aligned, the surgical instrument 1 can be engaged with the pedicle screw 100 simply by moving the surgical instrument 1 in the direction of the pedicle screw 100. However, if the positions of the surgical instrument 1 and the pedicle screw 100 are misaligned, they cannot be engaged as they are.

[0040] Conventionally, it has been necessary for the surgeon to align and engage the surgical instrument with the pedicle screw using the surgeon's technique.

[0041] According to the surgical instrument 1 of the present disclosure, when the positions of the surgical instrument 1 and the pedicle screw 100 are not aligned, when the surgical instrument 1 is moved in the direction of the pedicle screw 100, the cut-off portion 223 rides on the rod 110. Since the cut-off portion 223 is cut off obliquely with respect to the axial direction, if the surgical instrument 1 is simply moved in the direction of the pedicle screw 100, the surgical instrument 1 naturally rotates about the axis, and the positions of the surgical instrument 1 and the pedicle screw 100 will be aligned. Therefore, the surgeon can easily engage and attach the surgical instrument 1 to the pedicle screw 100.

[0042] Also, when removing the surgical instrument 1 from the pedicle screw 100, if one attempts to pull out the surgical instrument 1 from the pedicle screw 100, the hole 224 and the protrusion 101 are engaged, making it difficult to pull out. Thus, when the surgical instrument 1 is rotated about its axis, since the opening of the hole 224 is elliptical in shape, the engagement with the protrusion 101 is easily disengaged. Then, the cut-off portion 223 rides onto the rod 110. Thereby, the surgeon can easily remove the surgical instrument 1 from the pedicle screw 100.

[0043] For example, in a surgical instrument not provided with a cut-off portion, when the position of the surgical instrument and the pedicle screw is misaligned, it is difficult to easily attach the surgical instrument to the pedicle screw. Also, when removing the surgical instrument from the pedicle screw, even if the surgical instrument is rotated about its axis, the gripping portion only interferes with the rod, and the surgical instrument cannot be removed from the pedicle screw. Further, in a conventional surgical instrument, the opening of the hole provided in the gripping portion is rectangular, and it is difficult to rotate the surgical instrument in the axial direction in the first place.

[0044] 〔Summary〕 The surgical instrument according to Aspect 1 of the present disclosure includes an inner part and an outer part positioned to cover the inner part and movable in the longitudinal direction of the inner part. The outer part has a contact portion that can contact a rod. The inner part is composed of a plurality of gripping pieces and has a gripping portion at a first end for gripping the head portion of a pedicle screw. At least one of the corners on the first end side of the gripping piece has a cut-off portion cut obliquely with respect to the longitudinal direction.

[0045] When attaching the surgical instrument to the pedicle screw, the surgical instrument is moved toward the pedicle screw to attach the surgical instrument to the pedicle screw. If the positions of the surgical instrument and the pedicle screw are aligned, the surgical instrument can be attached to the pedicle screw simply by moving the surgical instrument in the direction of the pedicle screw. However, if the positions of the surgical instrument and the pedicle screw are misaligned, it cannot be attached as it is.

[0046] In this case, conventionally, the operator had to align and attach the surgical instrument with the pedicle screw using the operator's skill.

[0047] According to the above configuration, when the surgical instrument is moved in the direction of the pedicle screw, the cut-off portion rides on the rod, and the positions of the surgical instrument and the pedicle screw are automatically aligned. Therefore, the operator can easily attach the surgical instrument to the pedicle screw.

[0048] Also, when removing from the pedicle screw, the surgical instrument cannot be directly pulled out from the pedicle screw. Therefore, when the surgical instrument is rotated at that position, the cut-off portion rides up on the rod. Thereby, the operator can easily remove the surgical instrument from the pedicle screw.

[0049] The surgical instrument according to Embodiment 2 of the present disclosure is, in the above Embodiment 1, wherein the inner part is substantially cylindrical, and the longitudinal direction is the axial direction of the substantially cylindrical shape.

[0050] According to the above configuration, axial movement of the outer part with respect to the inner part can be easily performed.

[0051] The surgical instrument according to Embodiment 3 of the present disclosure is, in the above Embodiment 1 or 2, wherein the gripping piece is a portion of the side wall of the first end of the substantially cylindrical inner part other than the cut provided in the longitudinal direction of the first end.

[0052] According to the above configuration, when a force is applied to the gripping piece in a direction in which the diameter expands, a biasing force in the direction opposite to the force can be obtained. Thereby, the pedicle screw can be accurately gripped.

[0053] The surgical instrument according to Embodiment 4 of the present disclosure is, in any of the above Embodiments 1 to 3, wherein the cut-off portion is arranged on the second end side opposite to the first end with respect to the rod when the rod is arranged at the correct position.

[0054] According to the above configuration, when the surgical instrument rotates, the cut-off portion will ride on the rod, so that the surgeon can easily remove the surgical instrument from the pedicle screw.

[0055] The surgical instrument according to aspect 5 of the present disclosure, in any of the aspects 1 to 4, holds the pedicle screw with the holding portion, and with the outer portion in contact with the rod, moves the outer portion in the longitudinal direction of the inner portion, thereby adjusting the position of the rod. According to the above configuration, with the outer portion in contact with the rod, by moving the inner portion in the longitudinal direction, the position of the rod in the pedicle screw can be adjusted.

[0056] The surgical instrument according to aspect 6 of the present disclosure, in any of the aspects 1 to 5, each of the corners on the first end side of the holding piece has a cut-off portion that is cut off obliquely with respect to the longitudinal direction. According to the above configuration, no matter in which direction the surgical instrument is rotated about the axis, the surgical instrument can be easily engaged with the pedicle screw and can be easily removed from the pedicle screw.

[0057] The surgical instrument according to aspect 7 of the present disclosure, in any of the aspects 1 to 6, the inner surface of the holding portion has a tapered shape in which the inner diameter of the cross section perpendicular to the longitudinal direction becomes smaller as it moves away from the first end in the longitudinal direction. According to the above configuration, even if the axial position of the surgical instrument and the pedicle screw is displaced, the surgical instrument can be easily engaged with the pedicle screw.

[0058] The surgical instrument according to aspect 8 of the present disclosure, in any of the aspects 1 to 7, the holding portion has a locking portion that stops the movement of the pedicle screw in the direction away from the surgical instrument when the pedicle screw is held. According to the above configuration, the risk of the surgical instrument moving in the direction away from the pedicle screw can be reduced.

[0059] Also, when removing the pedicle screw, if an attempt is made to pull out the surgical instrument from the pedicle screw, the locking portion will catch and prevent removal. Since the locking portion is an instrument that locks the movement of the surgical instrument in the direction away from the pedicle screw, instead of moving the surgical instrument in the direction away from the pedicle screw, if it is rotated at that position, the locking of the locking portion will easily come off, and the cutting-off portion will ride onto the rod. Thereby, the surgeon can easily remove the surgical instrument from the pedicle screw.

[0060] The surgical instrument according to aspect 9 of the present disclosure is, in the aspect 8, wherein the locking portion is a hole into which a protrusion provided on the pedicle screw is locked, and the opening is a hole having a substantially elliptical shape. According to the above configuration, the pedicle screw can be locked in the axial direction of the surgical instrument, and can be easily removed in the circumferential direction.

[0061] The surgical instrument according to aspect 10 of the present disclosure is, in any one of aspects 1 to 9, wherein the gripping portion has two opposing gripping pieces. According to the above configuration, the pedicle screw can be easily gripped with the surgical instrument.

[0062] The surgical instrument according to aspect 11 of the present disclosure is, in the aspect 10, wherein the abutting portion is disposed between the two opposing gripping pieces of the gripping portion, and the distance between the gripping pieces of the gripping portion is substantially the same as the diameter of the rod. According to the above configuration, even when the rod is not disposed at the correct position of the pedicle screw, since the rod will be positioned between the gripping pieces, the rod can be easily abutted by the abutting portion.

[0063] As described above, the invention according to the present disclosure has been described based on the drawings and examples. However, the invention according to the present disclosure is not limited to the above-described embodiments. That is, the invention according to the present disclosure can be variously modified within the scope shown in the present disclosure, and embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the invention according to the present disclosure. In other words, it should be noted that those skilled in the art can easily make various deformations or modifications based on the present disclosure. Also, it should be noted that these deformations or modifications are included in the scope of the present disclosure.

Explanation of Signs

[0064] 1 Surgical instrument 10 Handle part 20 Main body part 21 Outer part 211 Contact part 22 Inner part 221 Gripping part 222 Gripping piece 223 Cutting-off part 224 Hole 110 Rod 100 Pedicle screw 105 Head part

Claims

1. An inner part, An outer part that is positioned to cover the inner part and is movable in the longitudinal direction of the inner part, and The outer part has a contact portion that can contact a rod, The inner part is composed of a plurality of gripping pieces and has a gripping portion at a first end for gripping the head portion of a pedicle screw, At least one of the corners on the first end side of the gripping piece has a cut-off portion that is cut off obliquely with respect to the longitudinal direction, A surgical instrument.

2. The inner part is substantially cylindrical, and the longitudinal direction is the axial direction of the substantially cylindrical shape. The surgical instrument according to claim 1.

3. The gripping piece is a portion other than a cut provided in the longitudinal direction of the first end among the side walls of the first end of the substantially cylindrical inner part. The surgical instrument according to claim 2.

4. The cut-off portion is arranged on the second end side opposite to the first end with respect to the rod when the rod is arranged at a correct position. The surgical instrument according to claim 1.

5. By gripping the pedicle screw with the gripping portion and moving the outer part in the longitudinal direction of the inner part with the outer part in contact with the rod, the position of the rod is adjusted. The surgical instrument according to claim 1.

6. All of the corners on the first end side of the gripping piece have a cut-off portion that is cut off obliquely with respect to the longitudinal direction. The surgical instrument according to claim 1.

7. The inner surface of the gripping portion has a tapered shape in which the inner diameter of a cross-section perpendicular to the longitudinal direction becomes smaller as it is farther from the first end in the longitudinal direction. The surgical instrument according to claim 1.

8. The surgical instrument according to claim 1, wherein the gripping portion has a locking portion that stops the movement of the pedicle screw in a direction away from the surgical instrument when the pedicle screw is gripped.

9. The surgical instrument according to claim 8, wherein the locking portion is a hole in which a protrusion provided on the pedicle screw is locked, and the opening of the hole is substantially elliptical.

10. The surgical instrument according to claim 1, wherein the gripping portion has two opposing gripping pieces.

11. The abutting portion is disposed between the two opposing gripping pieces of the gripping portion. The surgical instrument according to claim 10, wherein the distance between the gripping pieces of the gripping portion is substantially the same as the diameter of the rod.

Images