Extenders and Surgical Systems

Abstract

To reduce inconveniences by an inner part falling inward.SOLUTION: An extender (1) includes: an outer part (30) which is cylindrical and in which a screw engages a second end positioned below on an opposite side of an upper first end; at least a pair of inner parts (40) which have end surfaces (41) where an outer peripheral side projects to the first end side beyond an inner peripheral side and are arranged facing each other; and a pressing part (20) contacting end surfaces (41) of the inner parts (40). At least a part of the pressing part (20) is positioned on inner peripheral sides of the end surfaces (41).SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to an extender for use in surgery and a surgical system including the extender. [Background technology]

[0002] Extenders are surgical instruments used during surgical procedures. Extenders used in spinal surgery, for example, are cylindrical surgical instruments that allow pedicle screws to be inserted into the spine through small incisions. One type of extender consists of a locking cap, a nut, an outer part, and an inner part.

[0003] There are also counter torque devices that fix the extender to prevent unnecessary movement of the extender, and reduction tools that are fitted to the extender to reduce the spine. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Special Publication No. 2011-500267 Summary of the Invention [Problem to be solved by the invention]

[0005] When fixing the extender to the pedicle screw, the nut pushes the inner rod toward the pedicle screw. When pushing the inner rod with this nut, it is undesirable for the inner rod to tilt inward. For example, in spinal surgery, when the spine is finally fixed, a set screw for fixing the rod is set through the inside of the cylindrical extender, but this makes it difficult to pass the set screw. [Means for solving the problem]

[0006] An extender according to one embodiment of the present disclosure comprises a cylindrical outer portion having a second end located below, opposite an upper first end, into which a screw is fitted; at least a pair of inner portions arranged inside the outer portion and having an end face whose outer periphery protrudes more toward the first end than the inner periphery, and arranged opposite each other; and a push-in portion, at least a portion of which is located on the inner surface of the outer portion and contacts the end face of the inner portion, and at least a portion of which is located on the inner periphery side of the end face. [Effects of the Invention]

[0007] According to one aspect of the present disclosure, the outer circumferential side of the end face of the inner portion protrudes more toward the first end than the inner circumferential side, so that when the inner portion is pressed by the pressing portion, the inner portion does not collapse toward the inner circumferential side, i.e., in the direction in which the pair of inner portions face each other. This reduces the inconvenience caused by the inner portion collapsing inward. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is an external view illustrating an overview of an extender according to an embodiment of the present disclosure. [Figure 2] FIG. 2 is an exploded perspective view showing the details of the extender. [Figure 3] 10A and 10B are diagrams illustrating the relationship between a push-in portion and an outer portion in the extender. [Figure 4] 10A and 10B are diagrams illustrating the relationship between a push-in portion and an inner portion in the extender. [Figure 5] 10A and 10B are diagrams showing another example of the end surface of the inner portion. [Figure 6] FIG. 1 is an external view illustrating an overview of a counter torque according to an embodiment of the present disclosure. [Figure 7] FIG. 10 is a diagram showing details of a fitting portion of a counter torque. [Figure 8] FIG. 10 is a diagram illustrating a modified example of the counter torque. [Figure 9]10A and 10B are diagrams showing a flow of fitting a counter torque to an extender. [Figure 10] FIG. 1 is an external view illustrating an overview of a reduction tool according to an embodiment of the present disclosure. [Figure 11] 10A and 10B are diagrams showing modified examples of through holes in the handle portion of the reduction tool. DETAILED DESCRIPTION OF THE INVENTION

[0009] 〔overview〕 First, an overview of the extender 1 according to this embodiment will be described. In this embodiment, the extender 1 is assumed to be a surgical instrument used in spinal fixation surgery on a human body. The extender 1 is attached to a pedicle screw 50 when inserting the pedicle screw 50 into the spine. By using the extender 1, the pedicle screw 50 can be inserted into the spine while reducing the area of ​​the skin incision (wound). The extender 1 is not limited to a surgical instrument used in spinal surgery, but can be applied to any surgical procedure.

[0010] Fig. 1 shows the appearance of the extender 1 and the state in which a pedicle screw 50 is attached to the extender 1. 101 in Fig. 1 shows the state in which the pedicle screw 50 has been removed from the extender 1, and 102 in Fig. 1 shows the state in which the pedicle screw 50 has been attached to the extender 1.

[0011] As shown in FIG. 1, the extender 1 is, for example, cylindrical in shape overall. The cylindrical shape of the extender 1 is, for example, set so that the outer shape is a column. The corners of the cylindrical shape of the extender 1 may be chamfered, thereby preventing the doctor (operator) or patient from being accidentally injured. The length of the extender 1 in the longitudinal direction can be set appropriately depending on, for example, the surgical procedure, the doctor (operator), or the patient. The shape of the extender 1 is not limited to a columnar shape, and it may also be set in the shape of a square prism.

[0012] The pedicle screw 50 is attached to one end of the extender 1 (the second end 32 side of the outer part 30, which will be described later; Figure 2). The pedicle screw 50 attached to the extender 1 is fixed to the extender 1 by operating the operating part 10, which is inserted from the other end of the extender 1 (the first end 31 side of the outer part 30, which will be described later; Figure 2). The inner part 40 moves downward when the operating part 10 is operated.

[0013] In this embodiment, the side into which the operation portion 10 is inserted is also called the upper side of the extender 1, and the side into which the pedicle screw 50 is attached is also called the lower side of the extender 1.

[0014] [Details of Extender 1] Next, the extender 1 will be described in detail with reference to FIGS. 2 and 3. FIG. 2 is an exploded perspective view showing the details of the extender 1. As shown in FIG. 2, the extender 1 includes an outer part 30, an inner part 40, and a pushing part 20. The inner part 40 and the pushing part 20 are disposed inside the outer part 30, and the inner part 40 moves in the axial direction of the outer part 30 when pushed by the pushing part 20. The axis refers to the axis of the tube in the cylindrical outer part 30. For example, the symbol AX shown in FIG. 4 corresponds to the axis of the tube of the outer part 30. The axis of the tube is not limited to this, and for example, an axis relative to the outermost peripheral surface of the tube can be used.

[0015] (Outer part 30) The outer part 30 is cylindrical, with portions of the peripheral wall cut out in a U-shape at opposing positions. The U-shaped cutout includes a U-shaped portion 37 and a straight portion 38. Here, the description will be given using an example in which a portion of the side wall is cut out in a U-shape, but the outer part 30 is not limited to this. In the outer part 30, the shape in which a portion of the side wall is cut out does not have to be U-shaped, and it may be a complete cylinder with no cutouts.

[0016] A female screw 34 is provided on the inside of the first end 31 side of the outer part 30. The female screw 34 is adapted to be threadedly engaged with a male screw 21 (described later) provided on the outer surface of the push-in part 20.

[0017] Additionally, a first engagement portion 35 is provided on the inside of the second end 32 of the outer part 30. The first engagement portion 35 engages with a second engagement portion 53 (described later) of the pedicle screw 50, thereby engaging the extender 1 with the pedicle screw 50.

[0018] The side wall of the outer part 30 is provided with a hole 33 through which a second protrusion 42 (described later) of the inner part 40 protrudes. A lock indicator 36 is provided on the outer surface near the hole 33. The lock indicator 36 includes an unlocked position indicator 36a and a locked position indicator 36b, and indicates whether the pedicle screw 50 is locked to the extender 1 depending on the position of the second protrusion 42.

[0019] (Push-in part 20) Push-in portion 20 is cylindrical and has a male thread 21 on its outer surface. A recess 22 into which first protrusion 13 of operating portion 10 fits is provided on the side into which operating portion 10 is inserted, i.e., on the upper end. A bottom surface 23 on the lower side of push-in portion 20 is a flat surface that follows the tapered shape of end surface 41 of inner portion 40 (see 404 in FIG. 4), and contacts end surface 41 of inner portion 40. A fourth engagement portion 24 (see FIG. 4) is provided on the inside of bottom surface 23 of push-in portion 20.

[0020] At least a portion of the pushing portion 20 is disposed inside the outer portion 30, and the male thread 21 threadably engages with the female thread 34 of the outer portion 30. This will be described in more detail with reference to FIG. 3. FIG. 3 is a diagram showing the relationship between the outer portion 30 and the pushing portion 20. As shown in FIG. 3, the pushing portion 20 has a male thread 21 on the outer surface thereof. This male thread 21 threadably engages with the female thread 34 provided on the inside of the upper side of the outer portion 30. The outer diameter of the pushing portion 20 is long enough to allow it to be inserted into the outer portion 30. When the pushing portion 20 is inserted into the outer portion 30 and rotated, the pushing portion 20 moves within the outer portion 30 along the axis of the outer portion 30.

[0021] This allows the pushing portion 20 to be rotated while being moved in the axial direction of the outer portion 30. As the pushing portion 20 moves within the outer portion 30, the pushing portion 20 and the inner portion 40 move within the outer portion 30 as a unit.

[0022] (Inner part 40) The inner part 40 has a plate-like shape with a curved cross section in the short side direction so that it can be arranged inside the outer part 30. Two inner parts 40 are arranged as a pair inside the outer part 30 so as to face each other.

[0023] The inner part 40 has an end surface 41 that contacts the bottom surface 23 of the push-in part 20. In addition, a second protrusion 42 is provided on the outer surface of the inner part 40 (the surface that contacts the outer part 30). The second protrusion 42 is provided at a position that fits into the hole 33 of the outer part 30 when the inner part 40 is disposed inside the outer part 30. In addition, the portion where the second protrusion 42 is disposed is a leaf spring 43, and is biased in a pushing back direction when the second protrusion 42 is pressed toward the axial center.

[0024] Furthermore, fixing portions 44 are provided at the end portions 46 of the inner portion 40. The fixing portions 44 are provided on both ends of the end portion 46 so as to protrude downward. When the fixing portions 44 move downward and clamp a portion of the main body portion 51 of the pedicle screw 50, the pedicle screw 50 is fixed to the extender 1.

[0025] A portion of the longitudinal side surface of the inner part 40 has a protruding shape 45 that protrudes outward. When the inner part 40 is arranged inside the outer part 30, the protruding shape 45 sandwiches the straight part 38 of the U-shaped cutout part of the peripheral wall of the outer part 30, thereby stabilizing the movement of the inner part 40.

[0026] (Operation unit 10) The operating unit 10 fits into the pushing unit 20 to rotate the pushing unit 20. As shown in FIG. 2, the operating unit 10 includes a main body 15 and a shaft 11. The main body 15 is provided with a grip 16 that is held by the user and is provided with a through-hole 12. For example, in cases where it is difficult to rotate the pushing unit 20 by simply gripping the grip 16, a rod or the like can be passed through the through-hole 12, and the use of the rod makes it easier to rotate the pushing unit 20.

[0027] Furthermore, the main body 15 is provided with a first protrusion 13 that fits into the recess 22 of the push-in portion 20 .

[0028] The shaft portion 11 is a portion that is inserted into the inside of the push-in portion 20, and has a length that allows it to reach a position corresponding to the second protrusion portion 42 of the inner portion 40 when inserted.

[0029] (Pedicle screw 50) Pedicle screws 50 are inserted into the pedicles during spinal fixation surgery, and a rod (not shown) is passed between the pedicle screws 50 to fix the spine. The pedicle screw 50 consists of a main body portion 51 and a threaded portion 52. The main body portion 51 is cylindrical, and is provided with a second engagement portion 53 on the outside and a female thread 54 on the inside.

[0030] The second engagement portion 53 engages with the first engagement portion 35 of the outer part 30, thereby engaging the outer part 30 with the pedicle screw 50. The female thread 54 is used when setting a set screw (not shown) for fixing the rod.

[0031] [Details of the push-in portion 20 and the inner portion 40] Next, details of the contact surface between the pushing portion 20 and the inner portion 40 will be described with reference to Fig. 4. Fig. 4 is a diagram showing details of the contact surface between the pushing portion 20 and the inner portion 40.

[0032] Reference numeral 401 in FIG. 4 shows a side view of the extender 1. Reference numeral 402 in FIG. 4 shows a side view of the extender 1 seen from the same direction as 401, with the outer part 30 removed. Reference numeral 403 in FIG. 4 shows a cross section including the axial center when region IV in 402 is cut along the axis of the extender 1. Reference numeral 404 in FIG. 4 is an enlarged view of a portion of 403. Reference numeral 405 in FIG. 4 shows another example of 403.

[0033] 4, the bottom surface 23 of the pushing portion 20 comes into contact with the end surface 41 of the inner portion 40, and the inner portion 40 moves when the pushing portion 20 is pushed into the outer portion 30. Conversely, when the pushing portion 20 is pulled out of the outer portion 30, the fourth engagement portion 24 of the pushing portion 20 and the third engagement portion 47 of the inner portion 40 engage with each other, and the pushing portion 20 and the inner portion 40 move together.

[0034] As shown in 403 of FIG. 4, the outer periphery of end face 41 of inner portion 40 (the outermost periphery of inner portion 40) is set to be flush with the outer periphery of push-in portion 20. This improves the operability of inner portion 40. The shape of inner portion 40 is not limited to this, and as shown in 405 of FIG. 4, the outer periphery of end face 41A of inner portion 40A may be set to protrude outward beyond the outer periphery of push-in portion 20. This makes it easier to grasp the position of inner portion 40A. In this case, bottom surface 23 of push-in portion 20 may be a plane perpendicular to the axis rather than a plane following the tapered shape of end face 41.

[0035] 4, the end face 41 of the inner part 40 has a tapered shape in a cross section along the axis, with the outer circumferential side projecting upward (toward the first end 31) more than the inner circumferential side. The tapered shape of the end face 41 of the inner part 40 is set, for example, to be linear when viewed in a cross section parallel to the axis. The tapered shape is set to be inclined, for example, at an angle of 15° to 45° with respect to a plane perpendicular to the axis. This reduces the risk of the inner part 40 tipping toward the inner circumferential side, i.e., in the direction in which the inner part 40 faces, when the inner part 40 is pressed downward by the flat bottom surface 23 of the pressing part 20.

[0036] In spinal fixation surgery, the pedicle screw 50 fitted to the second end 32 is inserted into the spine, and then a rod (not shown) for fixing the spine is attached. The rod is set using a setting member, which is passed through the inner part 40, which is arranged opposite the inner surface of the outer part 30 of the extender 1, and reaches the pedicle screw 50.

[0037] As described above, the outer circumferential side of the end face 41 of the inner part 40 protrudes more toward the first end 31 than the inner circumferential side. This prevents the inner part 40 from tipping inward, i.e., in the direction in which the pair of inner parts face each other, when the inner part 40 is pushed in by the pushing part 20. This reduces the risk of the inner part 40 tipping inward, narrowing the passage through which the setting member passes, and preventing the setting member from reaching the pedicle screw 50.

[0038] [Modification] The end face 41 described above has a tapered shape in a cross section along the axis, with the outer periphery protruding more toward the first end 31 than the inner periphery. However, the end face 41 may have any shape as long as the outer periphery protrudes upward more than the inner periphery. For example, as shown in 501 and 501a in FIG. 5, the end face 41a may have a stepped shape in a cross section along the axis, with the outer periphery protruding more upward than the inner periphery. Here, 501a is an enlarged view of region V1 of 501. In this case, the bottom surface 23a of the pushing portion 20 may have a shape that matches the stepped shape of the end face 41a. That is, the bottom surface 23a may also have a stepped shape. This reduces the risk of the inner part 40 tipping toward the inner periphery, i.e., in the direction in which the inner part 40 faces, when the inner part 40 is pushed downward by the bottom surface 23 of the pushing portion 20.

[0039] 5, the cross section of the end face 41b along the axis may have a curved shape with the outer periphery protruding higher than the inner periphery, and concave upward. Here, 502a is an enlarged view of region V2 of 502. In this case, the bottom surface 23b of the pushing portion 20 may have a shape that matches the curved shape of the end face 41b. That is, the bottom surface 23b may have a curved shape that convex downward. This reduces the risk of the inner part 40 tipping toward the inner periphery, i.e., in the direction in which the inner part 40 faces, when the inner part 40 is pushed downward by the bottom surface 23 of the pushing portion 20.

[0040] Furthermore, as shown by 503 and 503a in FIG. 5, the end surface 41c may have a flat surface 411 perpendicular to the axis on the outer side, i.e., on the inner circumferential side of the outer part 30. Here, 503a is an enlarged view of region V3 of 503. In this case, the bottom surface 23c of the pushing-in portion 20 may have a shape that matches the shape of the end surface 41c. That is, the bottom surface 23c may have a flat surface perpendicular to the axis on the outer side, i.e., on the inner circumferential side of the outer part 30. This reduces the risk of the inner part 40 tipping toward the inner circumferential side, i.e., in the direction in which the inner part 40 faces, when the inner part 40 is pushed downward by the bottom surface 23 of the pushing-in portion 20.

[0041] [Counter torque] Next, the counter torque 2 will be described with reference to Figures 6 to 9. The counter torque 2 fits onto the first end 31 of the extender 1 to fix the extender 1, thereby reducing the risk of the extender 1 moving unnecessarily.

[0042] 601 in Fig. 6 is an external view showing an overview of the counter torque 2. As shown in Fig. 6, the counter torque 2 includes a fitting portion 201, a handle connection portion 202, and a handle 203. Here, the direction that forms the axis of the extender 1 when the extender 1 and the counter torque 2 are fitted together is defined as the z direction, which is perpendicular to the z direction, the axial direction of the handle connection portion 202 of the counter torque 2 is defined as the y direction, and the direction perpendicular to the y direction and the z direction is defined as the z direction.

[0043] 6 indicates the first end 31 of the extender 1. In the extender 1, the cross section of the outer part 30 is circular, and the outer circumferential surface of the first end 31 of the outer part 30 is made up of a circumferential part 312 and a missing part 311, which is a part missing from the circumference of the circle.

[0044] The handle connection part 202 of the counter torque 2 is axial, and is provided at one end of the shaft with a handle 203 having a diameter larger than that of the shaft. The other end of the handle connection part 202 is provided with a fitting part 201.

[0045] The fitting portion 201 is C-shaped and includes a curved region 211 and an abutment region 212. More specifically, the fitting portion 201 fits with the first end 31 of the outer part 30 of the extender 1 by covering a portion of the first end 31 with the C-shaped inner peripheral surface. The C-shaped inner peripheral surface has the abutment region 212 that abuts against the first end 31 including the defect portion 311 when fitted with the extender 1, and the curved region 211 that extends from the abutment region 212 in the axial direction of the extender 1.

[0046] The curved surface region 211 abuts against the circumferential portion 312 of the extender 1 before being fitted with the extender 1 .

[0047] The fitting portion 201 of the counter torque 2 will be described in detail with reference to Fig. 7. Fig. 7 is a diagram showing the fitting portion 201 of the counter torque 2 in detail. In Fig. 7, 701 is a perspective view of the fitting portion 201, and 702 is a view of the fitting portion 201 as seen from the +z direction, that is, the axial direction of the extender 1 when the extender 1 and the counter torque 2 are fitted together.

[0048] 7, the fitting portion 201 has a contact region 212 and a curved region 211 extending from the contact region 212. Of the contact region 212, a region 214 that contacts the circumferential portion of the extender 1 is flush with the curved region 211.

[0049] Furthermore, the axial length of curved region 211 near C-shaped opening 213 becomes shorter as it approaches C-shaped opening 213. In the example shown in 701 of Fig. 7, the axial length of curved region 211 is such that the length LH2 of the portion closer to opening 213 is shorter than the length LH1 of the portion farther from opening 213.

[0050] As indicated by 702 in FIG. 7, the fitting portion 201 has a C-shape when viewed from the +z direction.

[0051] 8, the curved surface region 211 of the counter torque 2 described above extends in one axial direction of the contact region 212 of the fitting portion 201. However, the present invention is not limited to this, and the curved surface region 211 may extend in both axial directions of the contact region 212, as shown in 802 of FIG. 8, for example. By extending in both directions, the user of the counter torque 2 can use the counter torque 2 without worrying about the orientation of the counter torque 2.

[0052] Next, a method for fitting the counter torque 2 to the extender 1 will be described with reference to Fig. 9. Fig. 9 is a diagram showing the flow of fitting the counter torque 2 to the extender 1.

[0053] As shown in 901 in FIG. 9 , first, the mating portion 201 of the counter torque 2 is fitted over the first end 31 of the extender 1 in the axial direction. At this time, as shown in 902 in FIG. 9 , the curved region 211 of the counter torque 2 comes into contact with the circumferential portion 312 of the extender 1, and the counter torque 2 can be rotated around the axis of the extender 1. When the counter torque 2 is rotated left and right as if pressing down in the axial direction, the counter torque 2 advances in the axial direction of the extender 1 at a position where the contact region 212 of the counter torque 2 comes into contact with the defective portion 311 and the circumferential portion 312 of the extender 1, as shown in 903 in FIG. 9 . This causes the extender 1 and the counter torque 2 to be fitted together.

[0054] Furthermore, after the extender 1 and the counter torque 2 are engaged, the distance of the C-shaped opening of the engaging portion 201 in a plane perpendicular to the axis is smaller than the diameter of the cross section of the first end 31 of the extender 1 so that the counter torque 2 does not slip away from the axis of the extender 1.

[0055] Furthermore, a system including the above-described extender 1 and the counter torque 2 fitted to the first end 31 of the extender 1 may be called a surgical system. The surgical system can be described as follows.

[0056] The surgical system includes an extender 1 and a counter torque 2 that fits onto a first end 31 of the extender 1 .

[0057] In the extender 1, the cross section of the outer part 30 is circular, and the outer circumferential surface of the first end 31 of the outer part 30 is made up of a circumferential part 312 and a missing part 311 that is a part missing from the circumference of the circle.

[0058] As described above, the counter torque 2 includes a fitting portion 201 that fits with the first end 31 of the extender 1. The fitting portion 201 is C-shaped and fits with the first end 31 of the outer part 30 of the extender 1 by covering a portion of the first end 31 with the C-shaped inner peripheral surface. The C-shaped inner peripheral surface has a contact region 212 that comes into contact with the first end 31, including the defective portion 311, when the counter torque 2 is fitted with the extender 1, and a curved region 211 that extends from the contact region 212 in the axial direction of the extender 1. The curved region 211 comes into contact with the circumferential portion 312 before fitting with the extender 1.

[0059] As a result, when fitting the fitting portion 201 of the counter torque 2 to the extender 1, the curved surface region 211 of the counter torque 2 can be easily aligned with the circumferential portion 312 of the first end 31 of the extender 1. Then, when the counter torque 2 is rotated in this state on a plane perpendicular to its axis, the counter torque 2 naturally moves in the axial direction at a position where it can abut against the missing portion 311 of the first end 31 of the extender 1, and the abutment region 212 of the counter torque 2 and the first end 31 of the extender 1 fit together. This allows the extender 1 to be fixed by the counter torque 2. Therefore, fitting with the extender 1 can be easily performed when fixing the extender 1.

[0060] [Reduction Tool] Next, the reduction tool 3 will be described with reference to Figures 10 and 11. The reduction tool 3 is fitted with the extender 1 and moves the extender 1 in the axial direction while maintaining its axis, thereby performing reduction, returning the vertebra into which the pedicle screw 50 has been inserted to its original position.

[0061] 10, reference numeral 1001 denotes an external view showing an outline of the reduction tool 3. Reference numeral 1002 denotes a cross section of the reduction tool 3 shown by reference numeral 1001 taken along line XX.

[0062] As shown in 1001 of FIG. 10, the reduction tool 3 includes a cylindrical main body 302 and a handle 301 that is held at one end of the main body 302 so as to be rotatable in the circumferential direction.

[0063] A movable part 304 that is movable in the axial direction of the cylinder is provided inside the cylinder of the main body part 302. The movable part 304 is cylindrical and has a fitting part 303 at one end that fits into the outer part 30, and has a male thread 305 on the outer circumferential surface on the side opposite to the fitting part 303.

[0064] The handle portion 301 is cylindrical and has a female thread 306 on its inner circumferential surface that screws into the male thread 305 of the movable portion 304. As the handle portion 301 rotates, the female thread 306 screws into the male thread 305 of the movable portion 304, thereby advancing the movable portion 304 in the axial direction of the tube of the main body portion 302.

[0065] The handle portion 301 also has a plurality of through holes 307 on the side surface.

[0066] A user of the reduction tool 3 rotates the handle portion 301 in the circumferential direction of the main body portion 302. When the handle portion 301 is rotated, the movable portion 304 advances in the axial direction of the main body portion 302, and the extender 1 engaged with the movable portion 304 moves in the axial direction. As the extender 1 moves, the pedicle screw 50 engaged with the extender 1 is pulled in the axial direction, and the vertebra into which the pedicle screw 50 is inserted is reduced.

[0067] In the example shown in FIG. 10, six through holes 307 are provided. 1002 in FIG. 10 shows a cross section taken along line XX in 1001. As shown in 1002, the through holes 307 are arranged to face each other across the central axis of the cylinder of the handle portion 301. In other words, they are arranged rotationally symmetrically around the axis. For example, through holes 307A and 307B face each other across the central axis of the cylinder. The number of through holes 307 is not limited to six, and any even number can be arranged to face each other across the central axis of the cylinder.

[0068] Figure 11 shows an example in which there are 12 through holes 307. Reference numeral 1101 in Figure 11 is a perspective view of handle portion 301 in which there are 12 through holes 307, and reference numeral 1102 in Figure 11 shows a cross section of handle portion 301 shown in reference numeral 1101 taken along line XI-XI. As shown in reference numeral 1102 in Figure 11, for example, through holes 307C and 307D are arranged so as to face each other across the central axis of the cylinder, in other words, rotationally symmetrically about the axis.

[0069] The through holes 307 are arranged so as to face each other across the central axis of the cylinder of the handle portion 301, which makes it easy to form the through holes 307. This is because when drilling holes from the side of the handle portion 301 to form the through holes 307, if the drill is passed through the handle portion 301, two through holes 307 can be formed in one operation.

[0070] As described above, if the number of through holes 307 is an even number, the workload for forming the through holes 307 is reduced, but it is also possible to have an odd number of through holes 307. Even if the number of through holes 307 is an odd number, the reduction tool 3 still functions satisfactorily.

[0071] In addition, handle portion 301 is provided with stopper 308 on the side opposite to the side where movable portion 304 is inserted, which prevents movable portion 304 from protruding from handle portion 301. Stopper 308 has a polygonal cross section and is provided with auxiliary hole 309 whose diameter is smaller than the diameter of the cylinder of movable portion 304.

[0072] Furthermore, a system including the extender 1 and the reduction tool 3 that fits into the extender 1 may be called a surgical operation system. The surgical operation system can be described as follows.

[0073] The surgical system includes an extender 1 and a reduction tool 3 that mates with the extender 1 .

[0074] The reduction tool 3 includes a main body 302 , a movable part 304 and a handle part 301 .

[0075] The main body 302 is cylindrical and covers the extender 1 when fitted to the extender 1 .

[0076] The movable part 304 is movable in the axial direction of the tube inside the tube of the main body part 302, is cylindrical, and has an engaging part 303 at its end that engages with the outer part 30, and has a male thread 305 on the outer surface opposite to the engaging part 303.

[0077] The handle portion 301 is cylindrical and has a female thread 306 on its inner circumferential surface that screws into the male thread 305 of the movable portion 304, and is held circumferentially rotatably at one end of the main body portion 302. As the handle portion 301 rotates, the female thread 306 screws into the male thread 305, causing the movable portion 304 to advance in the axial direction of the cylinder of the main body portion 302. The handle portion 301 also has a plurality of through holes 307 on its side.

[0078] The above configuration can be easily manufactured by simply providing through-hole 307 on the side of handle portion 301. Furthermore, gripping force can be maintained by through-hole 307. Furthermore, since only through-hole 307 is provided, there is little risk of the hand gripping handle portion 301 being pinched by the tool, and a reduction tool 3 that takes safety into consideration can be realized.

[0079] 〔summary〕 The extender 1 according to aspect 1 of the present disclosure comprises a cylindrical outer part 30 having a second end 32 located below, opposite the upper first end 31, into which a pedicle screw 50 (screw) is fitted; at least a pair of inner parts 40 arranged inside the outer part 30 and having end faces (41, 41a, 41b, 41c, 41X) whose outer periphery protrudes more toward the first end than the inner periphery, and arranged facing each other; and a push-in part 20, at least a portion of which is located on the inner surface of the outer part 30 and contacts the end faces (41, 41a, 41b, 41c) of the inner part 40, and at least a portion of the push-in part 20 is located on the inner periphery of the end faces (41, 41a, 41b, 41c, 41X).

[0080] The extender 1 according to aspect 2 of the present disclosure is similar to aspect 1 in that it includes an operating unit 10 that is inserted into the first end 31 of the outer part 30, and the operating unit 10 is capable of engaging with the pushing unit 20 and rotating the pushing unit 20 in a circumferential direction of the inner surface of the outer part 30, and the pushing unit 20 has a male thread 21 on its outer periphery that is threaded with a female thread 34 on the inner periphery of the first end 31 of the outer part 30, and when the pushing unit 20 moves toward the second end 32 due to rotation by the operating unit 10, it pushes the inner part 40 toward the second end 32.

[0081] In the extender 1 according to aspect 3 of the present disclosure, in aspect 1 or 2, the end face 41 may have a tapered shape in which the cross section along the axis of the tube protrudes more toward the first end 31 on the outer circumferential side than on the inner circumferential side.

[0082] In the extender 1 according to aspect 4 of the present disclosure, in aspect 1 or 2, the end face 41a may have a stepped shape in a cross section along the axis of the tube, with the outer circumferential side protruding more toward the first end than the inner circumferential side.

[0083] In the extender 1 according to aspect 5 of the present disclosure, in aspect 1 or 2, the end face 41b may have a cross section along the axis of the tube in which the outer circumferential side protrudes more toward the first end 31 than the inner circumferential side, and has a concave curve toward the first end 31.

[0084] The extender 1 according to a sixth aspect of the present disclosure is the same as the first or second aspect, wherein the end surface 41c may have a flat surface 411 perpendicular to the axis at the periphery of the axis of the tube.

[0085] The extender 1 according to aspect 7 of the present disclosure is any of aspects 1 to 6, wherein a second convex portion 42 is provided on the surface of the inner portion 40 facing the outer portion 30, and a hole portion 33 is provided in the outer portion 30 at a position corresponding to the second convex portion 42, and the surface on which the second convex portion 42 is provided may be a leaf spring 43 that is biased in a pushing direction when the second convex portion 42 is pressed toward the axial center.

[0086] The extender 1 according to aspect 8 of the present disclosure may be any of aspects 1 to 7, wherein the operating portion 10 has a shaft portion 11 of a length that reaches the position of the leaf spring 43 when engaged with the pushing portion 20.

[0087] The extender 1 according to aspect 9 of the present disclosure may be any of aspects 1 to 8, wherein the operating portion 10 has a first protrusion 13 protruding radially from the shaft portion 11, and the pushing portion 20 has a recess 22 that engages with the first protrusion 13.

[0088] A surgical operation system according to a tenth aspect of the present disclosure includes the extender 1 according to any one of the first to ninth aspects, and a counter torque 2 that fits onto the first end 31 of the extender 1, wherein the cross section of the outer portion 30 of the extender 1 is circular, and the outer circumferential surface of the first end 31 of the outer portion 30 is composed of a circumferential portion 312 and a missing portion 311 that is a portion missing from the circumference of the circle, and the counter torque 2 has a fitting portion 201 that fits onto the first end 31 of the extender 1, The mating portion 201 is C-shaped and fits into the first end 31 of the outer part 30 of the extender 1 by covering a portion of the first end 31 with the C-shaped inner surface, and the inner surface has a contact area 212 that abuts the first end 31 including the defective portion 311 when mated with the extender 1, and a curved area 211 extending from the contact area 212 in the axial direction of the extender 1, and the curved area 211 abuts against the circumferential portion 312 before mating with the extender 1.

[0089] A surgical operation system according to an eleventh aspect of the present disclosure is the same as the tenth aspect, in which the curved surface region 211 extends in both axial directions of the contact region 212.

[0090] In the surgical system of aspect 12 of the present disclosure, in aspect 10, the distance of the C-shaped opening of the engaging portion 201 in a plane perpendicular to the axis is smaller than the cross-sectional diameter of the first end 31 of the extender 1.

[0091] A surgical operation system according to a thirteenth aspect of the present disclosure is the same as that of the tenth aspect, in which the contact region 212 contacts the circumferential portion 312 of the extender 1 and is flush with the curved region 211 .

[0092] In the surgical system according to aspect 14 of the present disclosure, in aspect 10, the axial length of the curved region 211 near the C-shaped opening portion becomes shorter as it approaches the C-shaped opening portion.

[0093] A surgical operation system according to a fifteenth aspect of the present disclosure includes the extender 1 according to any one of the first to ninth aspects, and a reduction tool 3 that fits with the extender 1, wherein the reduction tool 3 is cylindrical and includes a main body portion 302 that covers the extender 1 when fitted with the extender 1, and a fitting portion 303 that is cylindrical and movable inside the cylinder of the main body portion 302 in the axial direction of the cylinder, and that fits with the outer portion 30 at its end. The handle portion 301 is cylindrical and has a female thread 306 on its inner surface that threads with the male thread 305 of the movable portion 304, and is held circumferentially rotatable at one end of the main body portion 302. As the handle portion 301 rotates, the male thread 305 threads with the female thread 306, thereby advancing the movable portion 304 in the axial direction of the tube of the main body portion 302. The handle portion 301 has a plurality of through holes 307 on its side.

[0094] A surgical operation system according to a sixteenth aspect of the present disclosure is the fifteenth aspect, wherein the through holes 307 are an even number and are arranged opposite each other across the central axis of the cylinder.

[0095] A surgical operation system according to a seventeenth aspect of the present disclosure is the same as the sixteenth aspect, except that the number of the through holes 307 is six.

[0096] In the surgical system of aspect 18 of the present disclosure, in aspect 15, the handle portion 301 is provided with a stopper 308 on the side opposite to the side into which the movable portion 304 is inserted, which prevents the movable portion 304 from protruding from the handle portion 301.

[0097] A surgical system according to aspect 19 of the present disclosure is the same as aspect 18, except that the stopper 308 has a polygonal cross section and is provided with an auxiliary hole 309 whose diameter is smaller than the diameter of the cylinder of the movable part 304.

[0098] The invention according to the present disclosure has been described above based on the drawings and examples. However, the invention according to the present disclosure is not limited to the above-described embodiments. In other words, the invention according to the present disclosure can be modified in various ways within the scope of 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 a person skilled in the art can easily make various modifications or corrections based on the present disclosure. It should also be noted that these modifications or corrections are included in the scope of the present disclosure. [Explanation of symbols]

[0099] 1 Extender 10 Control section 11 Shaft 12 Through holes 13 First convex part (convex part) 20 Push-in section 21 Male thread 22 recess 30 outer part 31 1st end 32 2nd end 33 Hole 34 Female thread 35 First engagement portion 36 Lock Indicator 40, 40X inner part 41, 41a, 41b, 41c, 41X end face 42 Second convex part (convex part) 43 Leaf spring 44 Fixed part 47 Third engagement part 50 Pedicle screw (screw) 51 Main body 52 Threaded part 53 Second engagement portion

Claims

1. a cylindrical outer portion having a first upper end and a second lower end opposite to the first upper end, the second lower end being fitted with a screw; At least a pair of inner parts are disposed inside the outer part and are arranged to face each other; a push-in portion at least part of which is located on the inner surface of the outer portion and which contacts the inner portion, the inner portion has an outer circumferential side that protrudes toward the first end more than an inner circumferential side, and has an end face on the outer circumferential side that faces toward the first end, An extender in which, when the pushing portion pushes the inner portion toward the second end, the bottom surface of the pushing portion contacts the end face of the inner portion at a position closer to the inner periphery than the outer periphery of the inner portion.

2. an operating portion that is inserted into the first end of the outer portion; the operating portion is fitted with the pushing portion and is capable of rotating the pushing portion in a circumferential direction of the inner surface of the outer portion, 2. The extender of claim 1, wherein the pushing portion has a male thread on its outer periphery that threads into a female thread on the inner periphery of the first end of the outer portion, and when the pushing portion moves toward the second end by rotation using the operating portion, the pushing portion pushes the inner portion toward the second end.

3. The extender according to claim 1 , wherein the end surface has a tapered shape in a cross section along the axis of the tube, with an outer circumferential side protruding more toward the first end than an inner circumferential side.

4. The extender according to claim 1 , wherein a cross section of the end face taken along the axis of the tube has a stepped shape in which an outer circumferential side protrudes more toward the first end than an inner circumferential side.

5. The extender according to claim 1 , wherein a cross section of the end face along the axis of the tube has an outer circumferential side that protrudes more toward the first end than an inner circumferential side, and has a concave curve toward the first end.

6. The extender according to claim 1 , wherein the end surface has a plane perpendicular to the axis at the periphery of the axis of the tube.

7. a convex portion is provided on a surface of the inner portion facing the outer portion, and a hole is provided in the outer portion at a position corresponding to the convex portion, 3. The extender according to claim 2, wherein the surface on which the protrusion is provided is a leaf spring that is biased in a pushing back direction when the protrusion is pressed toward the axis center.

8. The extender according to claim 7 , wherein the operating portion has a shaft portion having a length that reaches the position of the leaf spring when fitted into the pushing portion.

9. the operating portion has a protrusion that protrudes in a radial direction of the shaft portion, The extender according to claim 8 , wherein the push-in portion is provided with a recess that fits into the protrusion.

10. An extender according to any one of claims 1 to 9; a counter torque engaging the first end of the extender; the extender has a cross section of the outer portion that is circular, and an outer circumferential surface of the first end of the outer portion that is composed of a circumferential portion and a missing portion that is a portion missing from the circumferential portion of the circle, the counter torque has a fitting portion that fits with the first end of the extender, The fitting portion is a C-shaped inner circumferential surface of the C-shaped outer portion of the extender that covers a part of the first end of the outer portion of the extender, thereby fitting with the first end; the inner circumferential surface has a contact area that contacts the first end including the defective portion when the extender is fitted to the inner circumferential surface, and a curved surface area that extends from the contact area in the axial direction of the extender, the curved area abuts the circumferential portion before engaging with the extender; Surgical operation system.

11. The surgical system of claim 10 , wherein the curved surface region extends in both axial directions of the abutment region.

12. The surgical system of claim 10 , wherein a distance of the C-shaped opening of the fitting portion in a plane perpendicular to the axis is smaller than a diameter of a cross section of the first end of the extender.

13. The surgical system according to claim 10 , wherein the contact area that contacts the circumferential portion of the extender is flush with the curved area.

14. The surgical system according to claim 10 , wherein the axial length of the curved surface region in the vicinity of the C-shaped opening decreases with increasing distance from the C-shaped opening.

15. An extender according to any one of claims 1 to 9; a reduction tool that fits with the extender, The reduction tool a cylindrical main body portion that covers the extender when fitted to the extender; a movable part that is movable in the axial direction of the cylinder of the main body part, has a cylindrical shape and an engaging part at one end that engages with the outer part, and has a male screw on an outer peripheral surface opposite to the engaging part; a handle portion that is cylindrical and has a female thread on its inner circumferential surface that screws onto the male thread of the movable portion, and is held circumferentially rotatable at one end of the main body portion, and that threads the male thread onto the female thread as the handle portion rotates, thereby advancing the movable portion in the axial direction of the cylinder of the main body portion; The handle portion has a plurality of through holes on the side surface. Surgical operation system.

16. The surgical system according to claim 15, wherein the number of the through holes is an even number and the through holes are arranged opposite each other across the central axis of the cylinder.

17. The surgical system of claim 16, wherein the number of through-holes is six.

18. The surgical operation system according to claim 15, wherein the handle portion includes a stopper on the side opposite to the side where the movable portion is inserted, the stopper preventing the movable portion from protruding from the handle portion.

19. The surgical operation system according to claim 18, wherein the stopper has a polygonal cross section and is provided with an auxiliary hole having a diameter smaller than the diameter of the cylinder of the movable part.

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