Surgical cutting bur

Abstract

To provide a surgical cutting bur with improved cooling effect.SOLUTION: There is provided a surgical cutting bur comprising a shaft part rotating about a rotation axis, and a cutting part provided at a tip of the shaft part, where the cutting part has a spherical shape, and includes diamond abrasive grains on a surface and a longitudinal groove extending in an axial direction from the tip side, where the longitudinal groove is formed to be inclined in a rotation direction such that the tip position side is located closer to a rotation direction side than the shaft part side. This configuration can thus efficiently cool heat generated in the cutting part when the surgical bur is used by using the cooling water. Further, this makes it possible to provide a surgical bur with higher cooling efficiency at a site where precise surgical procedures for removing tissue around a nerve are performed.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a surgical cutting bar, which is a medical instrument for surgical operations.

Background Art

[0002] Conventionally, in surgical operations, there has been a medical instrument that removes tissues such as bones and tumors by rotating a surgical cutting bar having a cutting portion. The surgical cutting bar used in such a medical instrument includes a shaft portion that rotates about a rotation axis, and a cutting portion provided at the tip of the shaft portion. The cutting portion has a spherical shape, and a cutting surface is formed by attaching diamond abrasive grains to the surface (Patent Document 1). An operator uses the medical instrument by attaching the above-described surgical cutting bar to a handpiece constituting the medical instrument, rotating it, and pressing the rotating cutting surface against an object to be cut.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, since the surgical cutting bar described in Patent Document 1 is used by being rotated at a high speed (20,000 to 100,000 rpm), it generates heat due to friction when the cutting surface contacts the object to be cut. As a result, when the heated surgical cutting bar approaches the periphery of the object to be cut, there is a risk of directly thermally damaging the object to be cut and indirectly thermally damaging important structures such as nerves due to heat conduction from the object to be cut, and there is a problem that careful operation is required. It has been pointed out that the heat generation of the surgical cutting bar poses a clinical risk of osteonecrosis due to the heat of the object to be cut and thermal damage to nerves located in or adjacent to the bone due to heat conduction from the bone. Against such a background, in the field of performing delicate surgery to remove the tissue around the nerve, there is an increasing demand for a surgical cutting bar with higher cooling efficiency.

[0005] The present invention aims to solve the above problems and provides a surgical cutting bar with improved cooling effect.

Means for Solving the Problems

[0006] In order to solve the problems, a surgical cutting bar includes a shaft portion that rotates about a rotation axis and a cutting portion provided at the tip of the shaft portion. The cutting portion is spherical, has diamond abrasive grains on its surface, and has a longitudinal groove extending axially from the tip side. The longitudinal groove may be formed to incline in the rotational direction such that the tip position side is at a position on the rotational direction side rather than the shaft portion side.

Effects of the Invention

[0007] According to the present invention, it is possible to improve the cooling effect of the surgical cutting bar.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Mode for Carrying Out the Invention

[0009] (Embodiment) Hereinafter, embodiments will be described with reference to the drawings. Here, as a medical device using the surgical cutting bar according to the present invention, a surgical system, which is an orthopedic surgical instrument, is exemplified, but the present invention is not limited thereto, and a medical device for other uses such as dental use may be used.

[0010] <Surgical System> FIG. 1 is a schematic configuration diagram of a surgical system 100. The surgical system 100 includes a control unit 101, a handpiece 103, a connection cable 105 that connects the handpiece 103 to the control unit 101, and a foot switch 107.

[0011] The handpiece 103 includes an attachment 103a and a grip portion 103b. A surgical cutting bar 200 is detachably attached to the attachment 103a at the tip of the handpiece 103. The handpiece 103 is provided with a power source such as an air motor or an electric motor (electric motor) that rotationally drives the surgical cutting bar 200. The power source is rotated or stopped by a foot switch 107 connected to the control unit 101. The control unit 101 controls the rotational drive of the handpiece 103. In addition, a hand switch that is manually operated to rotate or stop the drive source of the handpiece 103 may be provided on the handpiece 103, and the operation may be performed by operating this hand switch. Further, the handpiece 103 may be other than that used in the present embodiment as long as it imparts an appropriate rotational driving force to the surgical cutting bar 200.

[0012] <Surgical Cutting Bar> FIG. 2 is a configuration diagram of the surgical cutting bar 200. Here, a virtual line indicating the rotation center of the surgical cutting bar 200 is defined as a rotation axis L. The surgical cutting bar 200 has a rod-shaped shaft portion 210 along the rotation axis L and a ball-shaped cutting portion 220 provided at one tip of the shaft portion 210. The ball shape referred to here means that when the surgical cutting bar 200 is rotated about the rotation axis L, the shape of the curved surface forming the cutting portion 220 includes the surface shape of a sphere or a rotational ellipsoid centered on the rotation axis L.

[0013] This surgical cutting bar 200 is formed of a hard material such as stainless steel or cemented carbide (tungsten carbide). At the base end of the shaft portion 210 on the side opposite to the cutting portion 220, a connecting portion 211 is provided which is connected and fixed to the rotation axis of the handpiece 103. The surgical cutting bar 200 fixed to the rotation axis rotates about the rotation axis L with the cutting portion 220 and the shaft portion 210 by the rotational drive of the handpiece 103.

[0014] In this surgical system 100, the operator rotates the surgical cutting bar 200 by operating the foot switch 107 while holding the handpiece 103. Then, with the cutting portion 220 of the surgical cutting bar 200 rotated, the operator presses it against an object to be excised such as bone or a tumor, and appropriately moves the handpiece 103 to cut the object to be excised. Note that the rotation direction R of the surgical cutting bar 200 is clockwise as viewed from the user holding the handpiece 103 in the case of this embodiment.

[0015] <Configuration of the cutting portion> Next, with reference to FIGS. 2 to 4, the configuration of the surgical cutting bar 200 will be described. In the following description, in the surgical cutting bar 200, based on the direction (axial direction) in which the rotation axis L extends, the side on which the cutting portion 220 is located is defined as the tip side, and the side on which the connecting portion 211 is located is defined as the rear end side. That is, in the cutting portion 220, based on the rotation axis L, the side on which the shaft portion 210 is located is the rear end side, and the side opposite to the shaft portion 210 is the tip side. Also, there is a position on the surface of the tip of the cutting portion 220 through which the rotation axis L passes. This position on the surface of the cutting portion 220 through which the rotation axis L passes is defined as the tip position M. For the same member or the same part, the same reference numeral is given to omit or simplify the description thereof.

[0016] FIG. 3 is a view of the cutting portion 220 of the surgical cutting bar 200 as seen from the axial direction of the rotation axis L. That is, FIG. 3 is a view of the surgical cutting bar 220 as seen from the tip position M side. On the cutting portion 220, diamond abrasive grains 221 are provided by electroplating so as to cover the entire spherical surface. The diamond abrasive grains 221 are granular materials obtained by finely crushing diamond. The cutting portion 220 on which the diamond abrasive grains 221 are electroplated has irregularities formed on the surface by the diamond abrasive grains 221. In this way, the surgical cutting bar 200 scrapes off tissues such as bone and tumor to be excised by bringing the cutting portion 220 provided with the diamond abrasive grains 221 on the surface into contact with the tissues while rotating.

[0017] Next, the cutting portion 220 will be described with reference to FIGS. 3 to 4. FIGS. 4(a) to 4(e) are views showing the shape of the cutting portion 220 in an easy-to-understand manner, with the diamond abrasive grains 221 omitted. FIG. 4(a) is a view of the cutting portion 220 as seen from the axial direction. FIG. 4(b) is a view of the cutting portion 220 as seen from the radial direction. FIG. 4(c) is a view seen from a position rotated 90 degrees about the tip position M as the center from the viewpoint of FIG. 4(b). FIG. 4(d) is a view seen from a position rotated 90 degrees about the tip position M as the center from the viewpoint of FIG. 4(c). FIG. 4(e) is a view seen from a position rotated 90 degrees about the tip position M as the center from the viewpoint of FIG. 4(d).

[0018] A first longitudinal groove 222 is formed in the cutting portion 220. The first longitudinal groove 222 is a portion recessed from the surface of the cutting portion 220 extending from the tip side to the rear end side in the cutting portion 220. In other words, the first longitudinal groove 222 is a groove extending from the tip position M side to the side where the shaft portion 210 is located in the cutting portion 220. Further, a second longitudinal groove 223 is formed in the cutting portion 220. The second longitudinal groove 223 is a portion that is recessed from the surface of the cutting portion 220 extending from the tip side toward the rear end side in the cutting portion 220. In other words, the second longitudinal groove 223 is a groove that extends from the tip position M side toward the side where the shaft portion 210 is located in the cutting portion 220.

[0019] Here, the first longitudinal groove 222 and the second longitudinal groove 223 have substantially the same shape and are arranged at equal intervals in the rotational direction in the cutting portion 220. In other words, the first longitudinal groove 222 and the second longitudinal groove 223 are grooves having a point-symmetrical shape with respect to each other with the tip position M as a reference in the cutting portion 220. Furthermore, the first longitudinal groove 222 and the second longitudinal groove 223 extending in the axial direction in the cutting portion 220 are formed in the cutting portion 220 so as to incline in the rotational direction of the surgical cutting bar 200 such that the tip position M side is a position on the rotational direction side rather than the shaft portion 210 side.

[0020] Next, a first transverse groove 224 extending from the first longitudinal groove 222 is formed in the cutting portion 220. The first transverse groove 224 extends in a direction opposite to the rotational direction of the surgical cutting bar 200 with the first longitudinal groove 222 as a starting point. Also, the internal space of the first transverse groove 224 and the internal space of the first longitudinal groove 222 are connected. In the present embodiment, two first transverse grooves 224 extending from the first longitudinal groove 222 are formed at intervals in the longitudinal direction.

[0021] Also, a second transverse groove 225 extending from the second longitudinal groove 223 is formed in the cutting portion 220. The second transverse groove 225 extends in a direction opposite to the rotational direction of the surgical cutting bar 200 with the second longitudinal groove 223 as a starting point. Also, the internal space of the second transverse groove 225 and the internal space of the second longitudinal groove 223 are connected. In the present embodiment, two second transverse grooves 225 extending from the second longitudinal groove 223 are formed at intervals in the longitudinal direction.

[0022] Here, the first transverse groove 224 and the second transverse groove 225 are arranged so as not to overlap in the rotational direction. That is, the first transverse groove 224 and the second transverse groove 225 are arranged with a shift in the longitudinal direction so as not to overlap in the rotational direction. Further, the first transverse groove 224 is formed to be shallower than the first longitudinal groove 222. In other words, the internal space of the first transverse groove 224 is formed smaller than the internal space of the first longitudinal groove 222. Similarly, the second transverse groove 225 is formed to be shallower than the second longitudinal groove 223. In other words, the internal space of the second transverse groove 225 is formed smaller than the internal space of the second longitudinal groove 224. In addition, diamond abrasive grains are provided on the surface of the cutting portion 220 by electrodeposition, and diamond abrasive grains are also provided in each of the above grooves 222, 223, 224, 225 to such an extent that the internal space of the groove is not completely filled.

[0023] The surgical cutting bar 200 configured as described above is used in a surgical operation as follows to excise tissues such as bone and tumor to be excised. First, the operator operates the foot switch 107 to drive the air motor or the electric motor to rotationally drive the surgical cutting bar 200. Then, while supplying cooling water to the cutting portion 220 of the rotating surgical cutting bar 200, the cutting portion 220 is brought into contact with the object to be excised to perform the operation of excising the object to be excised.

[0024] That is, when the cutting portion 220 rotates, the diamond abrasive grains constituting the surface of the cutting portion 220 come into contact with the object to be excised, and the object to be cut is scraped off. At this time, since the diamond abrasive grains come into contact with the object to be excised at high speed, frictional heat is generated and the temperature of the cutting portion 220 rises. The reason for performing the operation while supplying cooling water to the rotating cutting portion 220 is to cool the cutting portion 220 so that it does not become too hot due to frictional heat with the object to be cut.

[0025] And the supplied cooling water acts on the cutting portion 220 during the excision operation as follows. Refer to FIG. 5 showing the flow W of cooling water in the cutting part 220 during use. The cutting part 220 rotates in the supplied cooling water. As a result, the cooling water enters the inside of the first longitudinal groove 222 and the second longitudinal groove 223, and cooling is promoted in the axial direction of the cutting part 220. In particular, since the first longitudinal groove 222 and the second longitudinal groove 223 are regions recessed from the cutting part 220, it is easy to hold the cooling water inside the grooves, and the area where the cooling water contacts the cutting part 220 can be widened. Therefore, the cooling effect by the cooling water can be enhanced.

[0026] Also, the first longitudinal groove 222 and the second longitudinal groove 223 are formed in the cutting part 220 so as to incline in the rotation direction of the surgical cutting bar 200 such that the tip position M side is a position on the rotation direction side from the shaft part 210 side. That is, the first longitudinal groove 222 and the second longitudinal groove 223 are provided in the cutting part 220 so as to form a helix and the tip position M side extends toward the shaft part 210 side.

[0027] As a result, when the cutting part 220 rotates, a force associated with the rotation acts on the flow W of the cooling water that has entered the inside of the first longitudinal groove 222 and the second longitudinal groove 223. Thereby, a flow W of the cooling water from the tip position M side toward the shaft part 210 side is generated along the inside of the grooves 222, 223. That is, in the cutting part 220, an axial flow W of the cooling water that cools the cutting part 220 is formed from the tip position M side toward the shaft part 210 side, and the cooling effect of the cutting part 220 can be improved.

[0028] Furthermore, a first transverse groove 224 extending from the first longitudinal groove 222 is formed in the cutting part 220. The first transverse groove 224 extends in a direction opposite to the rotation direction of the surgical cutting bar 200 with the first longitudinal groove 222 as a base point. Also, the internal space of the first transverse groove 224 and the internal space of the first longitudinal groove 222 are connected. Since the first transverse groove 224 and the first longitudinal groove 222 are connected in this way and the first transverse groove 224 extends in a direction opposite to the rotation direction, a part of the cooling water located inside the first longitudinal groove 222 becomes a flow W of the cooling water reaching the first transverse groove 224 as the cutting part 220 rotates.

[0029] As a result, a flow W of cooling water in the rotational direction from the first longitudinal groove 222 toward the first transverse groove 224 is formed in the cutting portion 220, improving the cooling effect. In addition, with respect to the second transverse groove 225 extending from the second longitudinal groove 223, the same effect as that of the first transverse groove 224 and the first longitudinal groove 222 can be obtained.

[0030] Here, the first transverse groove 224 and the second transverse groove 225 are each formed to extend in the rotational direction from the corresponding longitudinal groove, but the first transverse groove 224 and the second transverse groove 225 are formed to have an axial displacement relationship so as not to overlap in the rotational direction of the cutting portion 220. In this way, since the transverse grooves 224 and 225 are axially displaced so as not to overlap in the rotational direction, the cutting portion 220 can be cooled over a wide range in the rotational direction.

[0031] Further, in the present embodiment, the positional relationship between the first longitudinal groove 222 and the second longitudinal groove 223, and the first transverse groove 224 and the second transverse groove 225 is formed to be point-symmetrical with respect to the tip position M. Since the cutting portion 220 is formed in this way, the weight of the cutting portion 220 can be balanced with respect to the rotation axis L. As a result, the vibration of the cutting portion 220 from the rotation axis L during rotation can be suppressed, and the cutting operation can be easily performed.

Explanation of Reference Numerals

[0032] L Rotation axis M Tip position W Flow of cooling water R Rotational direction of surgical cutting bar 100 Surgical operation system 101 Control unit 103 Handpiece 103a Attachment 103b Gripping portion 105 Connection cable 107 Foot switch 200 Surgical cutting bar 210 Shaft portion 211 Connection portion 220 Cutting portion 221 Diamond abrasive grains 222 First longitudinal groove 223 Second longitudinal groove 224 First transverse groove 225 Second transverse groove

Claims

1. A surgical cutting burr having a shaft portion that rotates around a rotation axis line and a cutting portion provided at a tip of the shaft portion, The cutting portion has a spherical shape, has diamond abrasive grains on its surface, and has longitudinal grooves extending in the axial direction from its tip side, The surgical burr according to claim 1, wherein the longitudinal grooves are formed so as to be inclined in the rotation direction so that the tip position side is located closer to the rotation direction than the shaft side.

2. The surgical burr according to claim 1 , wherein the cutting portion is provided with a lateral groove connected to the longitudinal groove.

3. The surgical burr of claim 2, wherein the transverse grooves extend from the longitudinal grooves in a direction opposite to the direction of rotation.

4. 4. The surgical burr according to claim 2, wherein a plurality of the lateral grooves are provided, and the lateral grooves are arranged offset from each other in the axial direction.

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