JP7692782B2 - Surgical Cutting Bur - Google Patents

Description

The present invention relates to a surgical cutting bar, which is a medical instrument used in surgical procedures.

A surgical burr has been used as a bone cutting device that is attached to a handpiece that is driven to rotate by a motor or a turbine to cut bones. A surgical cutting burr has a shaft that rotates around a rotation axis and a cutting part provided at the tip of the shaft.
Such a surgical cutting burr can perform rotary cutting of a cutting target such as bone by attaching a shaft portion to a portion of a handpiece that provides rotational output (Patent Document 1).

Japanese Patent Application Publication No. 10-43193

In medical settings where surgeries using surgical cutting burrs are performed, there is a need to reduce the burden on patients. One way to reduce the burden on patients is to shorten the surgery time.
Given this background, surgical cutting burrs are required to have high cutting power that leads to shorter surgery times, but there is a challenge in achieving this.

The present invention aims to solve the above problems and provide a surgical cutting bar with higher cutting power.

In order to solve the problem, a surgical cutting bar is provided which has a shaft portion which rotates around a rotation axis and a cutting portion formed on the tip side of the shaft portion, the cutting portion having a plurality of grooves extending spirally from the tip side of the shaft portion to the rear end side, each of the plurality of grooves being arranged at intervals in the rotational direction, and at a position sandwiched between adjacent grooves, a wavy peripheral blade having concave and convex portions which are uneven in a direction perpendicular to the rotational axis is formed in a spiral shape, the concave and convex portions have a curved shape, and the convex portions of each wavy peripheral blade are configured to be shifted in the axial direction relative to the convex portions of adjacent wavy peripheral blades in the rotational direction.

The present invention makes it possible to provide a surgical cutting bar with higher cutting power.

Configuration diagram of surgical operation system Side view of a surgical cutting burr FIG. 2 is an enlarged perspective view of the cutting portion of the surgical cutting burr; Cross-sectional view taken along the line A-A in FIG. Schematic diagram showing the shape of the wavy peripheral cutting edge Schematic side view of the cutting part seen from the radial direction

(Embodiment)
Hereinafter, an embodiment will be described with reference to the drawings.
Here, a surgical operation system 100, which is a bone surgery instrument, is exemplified as a medical device that uses a surgical cutting bar 200 according to the present invention.

<Surgical operation system>
FIG. 1 is a block 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 .

The handpiece 103 has an outer shell formed of a rod-shaped housing and is provided with an attachment 103a on the tip side. A surgical cutting burr 200 is detachably attached to the attachment 103a of the handpiece 103.
A power source such as an air motor or an electric motor (motor) for rotating the surgical cutting burr 200 is provided inside the handpiece 103. The power source is turned on or off by a foot switch 107 connected to the control unit 101. The control unit 101 controls the rotation of the handpiece 103.

The handpiece 103 is used by a surgeon who holds the grip portion 103b and directly operates it to bring the rotating surgical cutting bar 200 into contact with the affected area that is to be the cutting position.
The rotation or stopping of the driving source of the handpiece 103 may be performed by operating a hand switch that is manually provided on the handpiece 103. Also, the handpiece 103 may be any other type than that described in this embodiment as long as it provides an appropriate rotational driving force to the surgical cutting burr 200.

<Surgical cutting burr>
Next, the configuration of surgical cutting burr 200 will be described with reference to FIGS.
FIG. 2 is a side view of the surgical cutting burr 200, and a plan view seen from the radial direction when the tip of the surgical cutting burr 200 is facing downward. FIG. 3 is an enlarged perspective view of the cutting portion 220 of the surgical cutting burr 200. FIG. 4 is a cross-sectional view at the A-A position in FIG. 2. FIG. 5 is a cross-sectional view of each wavy peripheral blade 240 (241, 242, 243). In FIG. 5, in order to easily show the configuration of each wavy peripheral blade and the relationship between adjacent wavy peripheral blades, each wavy peripheral blade extending in a spiral from the tip to the rear end is cut along the spiral. FIG. 6 is a schematic diagram of the cutting portion 220, and a plan view seen from the radial direction when the tip of the surgical cutting burr 200 is facing downward.

The line O shown in the figure is the axis of rotation that indicates the center of rotation of the surgical cutting burr 200. In other words, the direction in which the axis of rotation O extends is the axial direction. The direction perpendicular to the axis of rotation O is the radial direction. The arrow R shown in the figure indicates the direction of rotation of the surgical cutting burr 200.

The surgical cutting burr 200 is a rod-shaped member formed of a hard material such as stainless steel, cemented carbide (tungsten carbide), etc. Such a surgical cutting burr 200 includes a shaft portion 210 that rotates about a rotation axis O, and a cutting portion 220 formed on the tip side of the shaft portion 210.
A connecting part 211 is provided at the rear end of the shaft part 210 opposite the cutting part 220, which is connected to and fixed to a rotating shaft located inside the attachment 103a of the handpiece 103. The surgical cutting burr 200 fixed to the rotating shaft of the attachment 103a rotates around the rotation axis O of the cutting part 220 and the shaft part 210 by the rotational drive of the handpiece 103.

In the surgical operation system 100 to which the surgical cutting burr 200 is attached, the surgeon operates the foot switch 107 while holding the handpiece 103 to rotate the surgical cutting burr 200. Then, the surgeon presses the cutting portion 220 of the surgical cutting burr 200 in the rotated state against a target to be resected, such as a bone, and moves the handpiece 103 appropriately to perform treatment by cutting the target to be resected.
In this embodiment, the rotation direction R of surgical cutting burr 200 is clockwise as viewed by a user holding handpiece 103 .

<Configuration of cutting part>
In the following description, the axial direction, which is the direction in which the axis of rotation O extends, of the surgical cutting burr 200 is taken as the reference, the direction perpendicular to the axial direction is taken as the radial direction, the side where the cutting portion 220 is located is taken as the tip side, and the side where the connecting portion 211 is located is taken as the rear side. Note that the same reference numerals are given to the same members or the same parts to omit or simplify the description thereof.

2 to 4, the cutting portion 220 has grooves 230 that extend spirally from the tip end side to the rear end side of the shaft portion 210. In the case of the present embodiment, there are three grooves 230, which are a first groove 231, a second groove 232, and a third groove 233.
The first groove 231, the second groove 232, and the third groove 233 are arranged in a spiral shape without intersecting with each other, with gaps between each other in the rotational direction.

In addition, a wavy peripheral blade 240 that is uneven in the radial direction, which is a direction perpendicular to the rotation axis, is formed on the ridge formed at the position sandwiched between adjacent grooves 230 (231, 232, 233). The wavy peripheral blade 240 is formed along the adjacent grooves 230, so it extends spirally from the tip side to the rear end side along the axial direction. In other words, the cutting section 220 is a section that includes the wavy peripheral blade 240 that is formed by connecting the grooves 230 and the radially uneven section.

In this embodiment, the wavy peripheral blades 240 formed in the cutting section 220 are a first wavy peripheral blade 241 formed at a position sandwiched between the first groove 231 and the second groove 232, a second wavy peripheral blade 242 formed at a position sandwiched between the second groove 232 and the third groove 233, and a third wavy peripheral blade 243 formed at a position sandwiched between the third groove 233 and the first groove 231.

With reference to FIG. 5, each of the wavy peripheral blades 240 (241, 242, 243) will be described.
5 shows a schematic cross-sectional view of the first wavy peripheral blade 241, a schematic cross-sectional view of the second wavy peripheral blade 242, and a schematic cross-sectional view of the third wavy peripheral blade 243. The tip of the first wavy peripheral blade 241 is referred to as tip 241c, the tip of the second wavy peripheral blade 242 is referred to as tip 242c, and the tip of the third wavy peripheral blade 243 is referred to as tip 243c. The positions of the respective tips 241c, 242c, and 243c in the rotational direction R are shown aligned.

In the first wavy outer peripheral blade 241, the portion that is convex in the radial direction is the first wavy outer peripheral blade convex portion 241a, and the portion that is concave in the radial direction is the first wavy outer peripheral blade concave portion 241b. This first wavy outer peripheral blade convex portion 241a is a portion that includes a peak that protrudes in the radial direction. In addition, the first wavy outer peripheral blade concave portion 241b is a portion that is a bottom that is concave in the radial direction.

Similarly, in the second wavy outer peripheral blade 242, the portion that is convex in the radial direction is referred to as the second wavy outer peripheral blade convex portion 242a, and the portion that is concave in the radial direction is referred to as the second wavy outer peripheral blade concave portion 242b. In addition, in the third wavy outer peripheral blade 243, the portion that is convex in the radial direction is referred to as the third wavy outer peripheral blade convex portion 243a, and the portion that is concave in the radial direction is referred to as the third wavy outer peripheral blade concave portion 243b.
The shapes of the concave and convex portions of the first wavy peripheral blade 241, the second wavy peripheral blade 242, and the third wavy peripheral blade 243 are generally the same.

Next, the structures of the first wavy peripheral blade 241, the second wavy peripheral blade 242, and the third wavy peripheral blade 243, and the positional relationship of each portion will be described.
The radially outer shape of the first wavy outer peripheral blade 241 forms a first straight portion 241d that is straight from the tip 241c of the first wavy outer peripheral blade 241 to the point where the shape of the first wavy outer peripheral blade recess 241b begins to be formed.
In other words, the radially outer shape of the first wavy outer blade 241 has a first straight portion 241d extending from the tip 241c, and first wavy outer blade recesses 241b and first wavy outer blade protrusions 241a are formed alternately from this first straight portion 241d toward the rear end, resulting in an uneven shape.

In addition, the radially outer shape of the second wavy outer peripheral blade 242 forms a second straight portion 242d that is straight from the tip 242c of the second wavy outer peripheral blade 242 to the point where the shape of the second wavy outer peripheral blade recess 242b begins to be formed.
In other words, the radially outer shape of the second wavy outer blade 242 has a second straight portion 242d extending from the tip 242c, and second wavy outer blade recesses 242b and second wavy outer blade protrusions 242b are formed alternately from this second straight portion 242d toward the rear end, resulting in an uneven shape.

Similarly, the radially outer shape of the third wavy outer blade 243 forms a third straight portion 243d that is straight from the tip 243c of the third wavy outer blade 243 to the point where the shape of the third wavy outer blade recess 243b begins to be formed.
In other words, the radially outer shape of the third wavy outer blade 243 has a third straight portion 243d extending from the tip 243c, and third wavy outer blade recesses 243b and third wavy outer blade protrusions 243a are formed alternately from this third straight portion 243d toward the rear end, resulting in an uneven shape.

Here, the size Δ241d of the first straight line portion 241d is configured to be shorter than the size Δ242d of the second straight line portion 242d. Also, the size Δ242d of the second straight line portion 242d is configured to be shorter than the size Δ243d of the third straight line portion 243d. In other words, the sizes of the respective straight line portions are configured to be different, and the relationship between the sizes of Δ241d, Δ242d, and Δ243d is Δ241d<Δ242d<Δ243d.

In the present embodiment, for example, in the case of the first wavy peripheral blade 241, if the distance between the peak positions of the adjacent first wavy peripheral blade protrusions 241a is L, then Δ242d-Δ241d=L/3. In other words, Δ242d is configured to be longer than Δ241d by L/3.
Because of this configuration, compared to the first wavy outer blade 241, the position where the first second wavy outer blade recess 242b on the tip side is formed is shifted by L/3 toward the rear end of the second wavy outer blade 242.
Accordingly, the series of second wavy outer blade convex portion 242a and second wavy outer blade concave portion 242b continuing from the first second wavy outer blade concave portion 242b at the tip side to the rear end side is also positioned L/3 toward the rear end relative to the first wavy outer blade 241.

Similarly, Δ243d−Δ242d=L/3. That is, Δ243d is configured to be longer than Δ242d by L/3.
Because of this configuration, compared to the second wavy outer blade 242, the position where the first third wavy outer blade recess 243b on the tip side is formed is shifted by L/3 toward the rear end.
Accordingly, the series of third wavy outer blade convex portion 243a and third wavy outer blade concave portion 243b continuing from the first third wavy outer blade concave portion 243b at the tip side to the rear end side is also positioned L/3 toward the rear end relative to the second wavy outer blade 242.

Since the cutting portion 220 is configured in this manner, in each of the wavy outer blades 240 (241, 242, 243), the convex portions (241a, 242a, 243a) of the respective wavy outer blades 240 (241, 242, 243) are positioned axially shifted from the convex portions (241a, 242a, 243a) of the wavy outer blades 240 (241, 242, 243) adjacent to each other in the rotational direction.
In other words, in the case of this embodiment, the peak position of the second wavy outer blade convex portion 242a of the second wavy outer blade 242 is shifted axially toward the rear end by L/3 relative to the peak position of the first wavy outer blade convex portion 241a of the first wavy outer blade 241.

Similarly, the peak position of the third wavy outer blade convex portion 243a of the second wavy outer blade 243 is shifted axially toward the rear end by L/3 relative to the peak position of the second wavy outer blade convex portion 242a of the second wavy outer blade 242.
This results in a positional relationship in which the peak positions of the first wavy outer peripheral blade convex portion 241a, the second wavy outer peripheral blade convex portion 242a, and the third wavy outer peripheral blade convex portion 243a do not overlap in the rotational direction.

Since the cutting portion 220 is configured as described above, it is possible to provide a surgical cutting bar 200 that reduces the burden associated with cutting on the bone to be cut, and has a higher cutting force that enables efficient cutting.
Specifically, in the cutting portion 220, the peak positions of the first wavy outer peripheral blade convex portion 241a, the second wavy outer peripheral blade convex portion 242a, and the third wavy outer peripheral blade convex portion 243a are shifted in the axial direction, so that they are positioned such that they do not overlap in the rotational direction.

In this embodiment, since there are three wavy peripheral blades 240, the deviation of the peak positions of the peripheral blade protrusions is L/3. In the case of four wavy peripheral blades 240, the deviation of the peak positions of the peripheral blade protrusions is L/4.
In other words, when there are N wavy peripheral blades 240, the deviation in the peak position of each peripheral blade protrusion is configured to be L/N.

When cutting the bone to be cut using the cutting portion 220, the peaks of each wavy outer blade convex portion that comes into contact with the cutting object can be shifted in the axial direction, thereby partially dispersing the cutting force acting on the cutting object.
As a result, when cutting bones, etc., a large force is not applied to a part at once, and the force is dispersed and cut efficiently. By configuring cutting unit 220 as described above, it is possible to reduce the impact of cutting on the bone to be cut, particularly when cutting human bones.

In addition, in this embodiment, the first straight portion 241d, the second straight portion 242d, and the third straight portion 243d are made to have different sizes, so that the positions at which the wavy outer peripheral blades are formed are shifted in the axial direction. As a result, the peak positions of the first wavy outer peripheral blade protrusion 241a, the second wavy outer peripheral blade protrusion 242a, and the third wavy outer peripheral blade protrusion 243a are in a positional relationship where they do not overlap in the rotational direction.

In this way, by appropriately changing the size of each straight section, the peak position of each outer blade convex section can be easily shifted during the processing work of forming the cutting section 220. In addition, when inspecting the quality of the surgical cutting burr 200, by measuring the size of the straight sections, it is possible to easily determine whether the shape of the cutting section 220 is accurately formed.

Furthermore, in this embodiment, all of the convex portions of the wavy outer blade 240 (241, 242, 243), namely the first wavy outer blade convex portion 241a, the second wavy outer blade convex portion 242a, and the third wavy outer blade convex portion 243a, and all of the concave portions, namely the first wavy outer blade concave portion 241b, the second wavy outer blade concave portion 242b, and the third wavy outer blade concave portion 243b, are cutting edges that cut the cutting object.
In other words, the entire spiral wavy outer cutting edge 240 (241, 242, 243) composed of curves forming concave and convex portions serves as a cutting edge capable of cutting the cutting object.

Since the cutting section 220 is configured in this manner, the cutting section 220 can perform cutting even if the cutting object comes into contact with the cutting section 220 from any direction.
In other words, the curves forming the recesses and protrusions are all cutting edges, so the cutting edges are always in contact with the cutting object. This makes it possible to perform cutting even if the cutting part 220 comes into contact with the cutting object in various directions and angles.

The surgical cutting burr 200 is used by a doctor by manually operating the attached handpiece 103, bringing the cutting portion 220 into contact with the affected area to be cut in various orientations and angles. Therefore, configuring it as described above is effective in shortening the surgery time and reducing the burden on the patient.
In particular, since the wavy peripheral blade 240 (241, 242, 243) has an uneven curved shape, the amount of contact that the wavy peripheral blade 240 makes with the cutting object at one time during cutting is reduced, thereby reducing the cutting resistance during cutting. This reduces the cutting resistance and the burden on the affected area during cutting.

Next, the twist angle of the wavy peripheral blade 240 (241, 242, 243) will be described with reference to Fig. 6. The twist angle is the angle between the rotation axis O of the surgical cutting bar 200 and the wavy peripheral blade 240 (241, 242, 243) that is formed by being twisted in a spiral shape.
The figure shows a schematic diagram of the relationship between the wavy peripheral blade 240 and the rotation axis O. When the surgical cutting burr 200 is viewed from the radial direction, the angles between the wavy peripheral blade 240 and the rotation axis O are θ1, θ2, and θ3 from the tip side.

The surgical cutting burr 200 rotates clockwise in the rotation direction R. The wavy peripheral blade 240 is formed in a spiral shape around the rotation axis O of the surgical cutting burr 200. In addition, the cutting edge of the wavy peripheral blade 240 that cuts the cutting target faces rightward, the same as the rotation direction R.
The corrugated peripheral cutting edge 240 is configured so that the twist angle is larger at the rear end side than at the front end side. In other words, the angle between the corrugated peripheral cutting edge 240 and the rotation axis O has the following relationship.
θ1<θ2<θ3

In this way, by configuring the wavy peripheral blade 240 so that the twist angle is larger at the rear end side than at the tip end side, the strength of the cutting portion 220 of the surgical cutting bar 200 can be improved.
In particular, the strength can be improved by increasing the twist angle on the rear end side of the wavy peripheral cutting edge 240. In addition, by decreasing the twist angle on the tip side of the wavy peripheral cutting edge 240, the tip can form a cutting section 220 that takes advantage of the flexibility of the metal.
This allows the surgical cutting burr 200 to have improved strength while allowing delicate cutting operations to be performed at the flexible tip side.

3 and 6, in the cutting portion 220 of the surgical cutting bar 200, the wavy peripheral cutting edges 240 (241, 242, 243) are oriented in the same direction as the rotation direction R and are twisted in the opposite direction to the rotation direction R.
In the present embodiment, the surgical cutting burr 200 has a right-handed rotation direction R, so the wavy peripheral blades 240 (241, 242, 243) face the right direction. That is, when the surgical cutting burr 200 rotates rightward, the wavy peripheral blades 240 (241, 242, 243) face the cutting target. The wavy peripheral blades 240 (241, 242, 243) are twisted leftward and formed in a spiral shape.

The surgical cutting burr 200 of the present embodiment has a so-called right-hand blade and left-hand twist. When viewed from the radial direction with the tip of the surgical cutting burr 200 facing downward, the spiral portion slopes upward to the left.
In this way, because surgical cutting burr 200 has cutting portion 220 with a right-hand blade and a left-hand twist, a force acts from the tip side to the rear end when cutting an object to be cut. In other words, a force acts in a direction that pushes surgical cutting burr 200 into attachment 103a of handpiece 103 to which surgical cutting burr 200 is attached.
Therefore, when cutting the affected area of the patient, the surgical cutting burr 200 can be prevented from falling off toward the patient.

6, cutting portion 220 of surgical cutting burr 200 is configured in a tapered shape that widens from the tip side to the rear end side. In other words, cutting portion 220 is shaped so that the diameter gradually increases from the tip side to the rear end side.
In this way, by narrowing the diameter at the tip end of the cutting section 220, the amount of cutting at the affected area is reduced, thereby reducing the burden on the patient, and by increasing the diameter at the rear end, strength sufficient to withstand cutting can be achieved.

O Rotation axis R Rotation direction of surgical cutting bur 100 Surgical operation system 101 Control unit 103 Handpiece 103a Attachment 103b Grip portion 105 Connection cable 107 Foot switch 200 Surgical cutting bur 210 Shaft portion 211 Connection portion 220 Cutting portion 230 Groove 231 First groove 232 Second groove 233 Third groove 240 Wave-shaped peripheral blade 241 First wave-shaped peripheral blade 242 Second wave-shaped peripheral blade 243 Third wave-shaped peripheral blade

Claims (4)

A surgical cutting bar having a shaft portion that rotates around a rotation axis and a cutting portion formed on a tip side of the shaft portion,
The cutting portion has a plurality of grooves extending in a spiral shape from the front end side to the rear end side of the shaft portion, the plurality of grooves being arranged at intervals in the rotation direction, and a wavy peripheral cutting edge having concave and convex portions that are uneven in a direction perpendicular to the rotation axis is formed in a spiral shape at a position sandwiched between adjacent grooves, and the concave and convex portions are curved in shape,
A surgical cutting bar characterized in that, in the wavy peripheral blade, the convex portion of each of the wavy peripheral blades is axially shifted from the convex portion of the wavy peripheral blade adjacent to it in the rotational direction. The surgical cutting bar according to claim 1, characterized in that the spiral wavy peripheral blade has a larger twist angle at the rear end than at the tip end. The surgical cutting bar according to claim 1, characterized in that in the cutting section, the wavy peripheral blade faces in the direction of rotation and is twisted in the opposite direction to the direction of rotation. 2. The surgical cutting burr according to claim 1, wherein the cutting portion has a tapered shape that widens from a tip side to a rear end side.

Images