Bone extractor

Abstract

The purpose of the present invention is to provide a bone extractor capable of easily extracting a bone such as a femoral head even in an operation such as an MIS. The present invention is provided with: a shaft part (12); a handle part (11) disposed on the base end side of the shaft part; a tapered screw part (20) that is formed on the tip side of the shaft part and tapers toward the tip side; and a blade edge portion (30) disposed on the tip side of the tapered screw portion. The present invention is provided with: a tapered screw section (21) in which a helical thread section (21) is formed on the surface of a shaft section (25), which is the shaft of the tapered screw section, and an insert blade section (32) which is a plate-shaped body (31) having a tapered tip side and which has a cutting edge (32) formed from a rake surface (34) formed at at least one lateral end; at least one surface on the base end side of the rake face is directly connected to the top surface on the front end side of the threaded part, or at least one surface on which the base end side of the rake face extends is directly connected to the top surface on the front end side of the threaded part.

Description

Technical Field

[0001] The present invention relates to a bone extractor during surgery. Background Art

[0002] In orthopedics and the like, for example, in total hip replacement, bones (femoral head, etc.) are cut and extracted. In this case, the femoral head is located deep inside the body, so a bone extractor is used.

[0003] Figure 7 Patent Document 1 Figure 6 The bone extractor 100 is composed of a handle 101, a shaft 102, and a tapered screw 103. The tapered screw 103 is screwed into and locked in the femoral head to remove the femoral head from the surgical field.

[0004] Figure 8 Also, Patent Document 1 Figure 1 The bone extractor 200 is composed of a handle 201, a shaft 202, and a wing-shaped blade 203. The wing-shaped blade 203 is inserted and locked in the femoral head to remove the femoral head from the surgical field.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: China Utility Model Announcement No. CN21495952 Summary of the invention

[0008] Problems to be solved by the invention

[0009] The surface of the bone is covered by hard cortical bone, and the interior is made up of soft spongy bone. Figure 7 as well as Figure 8 In bone extractors such as the above, the bone is usually inserted into the bone from the spongy bone of the cut surface. If the bone extractor is inserted from the cut line of the neck of the femoral head, the surgical field needs to be greatly expanded, and the length of the skin incision line becomes longer.

[0010] When a bone extractor is screwed into the cortical bone on the surface of the femoral head in order to shorten the length of the skin incision line for minimally invasive surgery (MIS), the bone extractor cannot penetrate and get stuck inside the bone due to the high hardness of the cortical bone.

[0011] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a bone extractor that can easily extract bones such as the femoral head even in surgery such as MIS.

[0012] Solutions to Solve Problems

[0013] The bone extractor of the present invention, which has been made to solve the above-mentioned problems, has an excellent function of being inserted into and locked in the bone from the surface of the bone.

[0014] The present invention (1) is a bone extractor, comprising: a shaft; a handle, which is arranged at the base end side of the shaft; a tapered screw portion, which is formed at the front end side of the shaft and tapers toward the front end side; and a blade edge portion, which is arranged at the front end side of the tapered screw portion, wherein the tapered screw portion has a spiral thread portion formed on the surface of the shaft of the tapered screw portion, i.e., the shaft portion; the blade edge portion is a plate-like body with a tapered front end side and has a cutting edge formed by a front cutting face formed at at least one lateral end portion, at least one of the front cutting faces having a base end side surface directly connected to the top surface of the front end side of the thread portion, or at least one of the front cutting faces having an extended setting surface at the base end side directly connected to the top surface of the front end side of the thread portion.

[0015] In the present invention (1), the bone extractor comprises: a shaft; a handle, which is arranged at the base end side of the shaft; a tapered screw, which is formed at the front end side of the shaft and is tapered toward the front end side; and a blade, which is arranged at the front end side of the tapered screw, wherein the tapered screw has a spiral thread portion formed on the surface of the shaft, i.e., the shaft portion, of the tapered screw, and the blade is a plate-like body tapered at the front end side, and has a cutting edge formed by a rake face formed at a lateral end, at least one of the surfaces at the base end side of the rake face is directly connected to the top surface at the front end side of the thread portion, or at least one of the extended surfaces at the base end side of the rake face is directly connected to the top surface at the front end side of the thread portion. Therefore, the blade can easily perforate the cortical bone, the blade opens a hole sharply and pointedly, and the tapered screw connected from the blade by the ridge can bite into the cortical bone without reducing the momentum.

[0016] In most cases, the front end of the existing products is tapered, which is suitable for opening holes in fine pores or soft spongy bones. However, for hard cortical bones, the more the insertion goes in, the lower the propulsion force becomes.

[0017] Here, the reason for setting "at least one of the base end sides of the rake face" is that when the rake face has two faces and the spiral thread portion is a double helix, there may be a case where the two faces are connected. Similarly, there may be a case where the number of connected parts is three or four.

[0018] The present invention (2) is the bone extractor of the present invention (1), characterized in that a notch for self-tapping is formed in the threaded portion along the axial direction.

[0019] In the present invention (2), a notch for self-tapping is formed in the threaded portion along the axial direction. Therefore, after the blade edge is embedded from the cortical bone into the spongy bone, when the tapered screw portion hits the cortical bone, the notch can be used to self-tap the cortical bone, thereby making it easier to insert and fix the bone extractor in the bone.

[0020] Effects of the Invention

[0021] According to the present invention, it is possible to provide a bone extractor that can easily extract bones such as a femoral head even in surgery such as MIS. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a schematic diagram of extracting a femoral head during an artificial hip joint surgery using the bone extractor according to the first embodiment of the present invention.

[0023] Figure 2 It is a perspective view of the bone extractor according to the first embodiment of the present invention.

[0024] Figure 3 1 and 2 are a top view (A) and a front view (B) of the bone extractor according to Embodiment 1 of the present invention.

[0025] Figure 4 It is a plan view showing the front end portion of the bone extractor according to the first embodiment of the present invention.

[0026] Figure 5 It is a perspective view showing the front end portion of the bone extractor according to the first embodiment of the present invention.

[0027] Figure 6 It is a perspective view showing the front end portion of the bone extractor according to the second embodiment of the present invention.

[0028] Figure 7 This is a conventional bone extractor described in Patent Document 1.

[0029] Figure 8 This is a conventional bone extractor described in Patent Document 1. DETAILED DESCRIPTION

[0030] Hereinafter, embodiments of the present invention will be described in detail based on the drawings. Note that the following embodiments are merely preferred examples in nature and are not intended to limit the scope of the present invention, its applications, or its uses.

[0031] <Implementation Method 1>

[0032] Figure 1 to Figure 5 Embodiment 1 of the bone extractor of the present invention is shown.

[0033] Figure 1 A state where the femoral head 5 is extracted using the bone extractor 10 according to the first embodiment is shown.

[0034] During the operation, in order to form an operation field 1 by incising the skin with a scalpel, the incision hooks 2, 3 and 4 are used. The femoral head 5 is cut off by an electric saw or the like at the bone cutting line 7 of the femoral neck 6. A bone extractor 10 is screwed into the cortical bone of the femoral head 5. After the bone extractor 10 is fully screwed into the femoral head 5, the femoral head 5 can be pulled out of the body by pulling the bone extractor 10.

[0035] Figure 2 1 is a perspective view of a bone extractor 10 according to Embodiment 1 of the present invention. The bone extractor 10 includes a handle 11 for rotating the shaft 12 and rotating and pressing the tapered screw 20. The handle 11 and the shaft 12 are in a T-shape, but are not necessarily limited to this shape. In addition, the present invention can also be applied to an object that uses power other than hand cranking.

[0036] A tapered screw portion 20 is formed on the front end side of the shaft portion 12. The tapered screw portion 20 is formed at a shaft portion 25 (see Figure 4 ) is formed with a spiral thread portion 21. A blade edge portion 30 is provided at the front end of the tapered screw portion 20.

[0037] Figure 3 The bone extractor 10 is a top view (A) and a front view (B) of the first embodiment of the present invention. The bone extractor 10 includes a handle 11 , a shaft 12 , a tapered screw 20 , a threaded portion 21 , and a blade 30 .

[0038] Figure 4 1 is a plan view showing the front end of the bone extractor according to the first embodiment of the present invention, showing the front end side portion of the tapered screw part 20 and the blade edge part 30. The threaded portion 21 of the tapered screw part 20 is composed of a bottom surface 23 on the surface of the shaft part 25, an inclined surface 24 connected to the bottom surface 23, and a top surface 22 connected to the inclined surface 24. In the blade edge part 30, a first cutting edge 32 and a first relief surface 33 are formed on a plate-like body 31 which is a main body having a tapered plate shape at the front end side.

[0039] In the first embodiment, the plate-like body 31 is one piece, but a modified example in which two plate-like bodies intersect at right angles and there are four cutting edges may be used. The number of plate-like bodies may be three, four, or the like.

[0040] Figure 5 1 is a perspective view showing the front end of the bone extractor according to the first embodiment of the present invention, wherein the blade edge portion 30 is formed with a first cutting edge 32 formed by a first rake face 34 formed at a lateral end of a plate-like body 31. A first relief face 33 is formed near the front side of the first cutting edge 32. The first rake face 34 is connected to the top face 22 of the threaded portion 21 via a connecting face 35.

[0041] By making Figure 5 With such a structure, the blade edge 30 can penetrate the cortical bone sharply, and the tapered screw portion 20 connected to the blade edge 30 through the connecting surface 35 can bite into the cortical bone without reducing the momentum. In addition, the cutting powder of the bone cut by the first cutting edge 32 is along the Figure 4 The inclined surface 24 and the bottom surface 23 of the threaded portion 21 shown are efficiently discharged.

[0042] <Implementation Method 2>

[0043] Figure 6 3 is a perspective view showing the front end of the bone extractor according to the second embodiment of the present invention, wherein a blade edge portion 30 is formed on the front end side of the tapered screw portion 20. A second cutting edge 36 is formed by a second rake face 37 and a second flank face 38 on the side opposite to the first cutting edge 32, and the first cutting edge 32 and the second cutting edge 36 intersect at an apex 39. The apex 39 penetrates into the cortical bone, and the first cutting edge 32 and the second cutting edge 36 dig out the cortical bone.

[0044] The bone extractor of the second embodiment is characterized in that a notch 40 for self-tapping is provided on the front end side of the tapered screw part 20. The notch 40 is formed in the two threaded teeth 21 on the front end side. The notch 40 may be formed on the opposite side of the axis rotation 180°, or may be provided at three or four locations axially symmetrically. The notch 40 includes a first notch surface 42 and a second notch surface 43, and a notch cutting edge 41 is formed on the boundary line between the top surface 22 and the first notch surface 42. With the notch cutting edge 41, when cortical bone remains after the cortical bone is excavated by the blade edge 30, the notch cutting edge 41 can be used to perforate the cortical bone.

[0045] Possibility of Industrial Application

[0046] As described above, the bone extractor of the present invention can be suitably used as a bone extractor that can easily extract bones such as the femoral head even in surgeries such as MIS.

[0047] Explanation of symbols

[0048] 1—surgical field; 2, 3, 4—opening hook; 5—femoral head (bone); 6—bone neck; 7—bone cutting line; 10—bone extractor; 11—handle; 12—shaft; 20—tapered screw; 21—threaded tooth; 22—top surface; 30—blade edge; 31—plate-like body; 32—first cutting edge; 33—first back cutting surface; 34—first rake cutting surface; 35—connecting surface; 36—second cutting edge; 37—second rake cutting surface; 38—second back cutting surface; 39—apex; 40—notch; 41—notch cutting edge; 42—first notch surface; 43—second notch surface.

Claims

1. A bone extractor, comprising: a shaft; a handle disposed at a base end of the shaft; a tapered screw portion formed at a front end of the shaft and tapering toward the front end; and a blade portion disposed at a front end of the tapered screw portion. The bone extractor is characterized in that The tapered screw portion has a spiral thread portion formed on the surface of the shaft portion, which is the axis of the tapered screw portion. The blade edge is a plate-like body with a tapered front end and has a cutting edge formed by a rake face formed at at least one lateral end. At least one of the base end side surfaces of the rake face is directly connected to the top surface of the front end side of the thread portion, or at least one of the extended surfaces of the base end side of the rake face is directly connected to the top surface of the front end side of the thread portion.

2. The bone extractor according to claim 1, characterized in that: A notch for self-tapping is formed in the threaded portion along the axial direction.

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