JP6341506B2 - Cutting tools and bone surgery instruments - Google Patents

Description

  The present invention relates to a cutting tool and an instrument for bone surgery, and more specifically, includes a shank to which a rotational force around an axis is applied, and a tool head that is positioned in front of the shank and contacts a predetermined cutting object. The present invention relates to a cutting tool and an instrument for bone surgery.

Surgical treatment is performed for diseases such as intervertebral disc herniation, oral cavity tumors and nerve tumors. Specifically, in an herniated disc, for example, a vertebral arch is incised (also referred to as a fenestration) to remove pressure on the spinal canal. Further, before excising the tumor, the jaw bone may be cut for an intraoral tumor, and the bone near the tumor may be cut for a nerve tumor.
A predetermined cutting tool (also called a round bar or an end mill) is used for bone cutting, but the bone must be cut so as not to damage nerves and the like. Therefore, for example, Patent Document 1 discloses a technique for controlling the driving of a tool so as not to cut the living tissue excessively.

5 and 6 are diagrams for explaining a conventional round bar. As shown in FIG. 5, the round bar 130 has a shank 131 attached to a handpiece (not shown), and a rotational force about an axis is applied to the shank 131 from a motor (not shown).
A tool head 134 is provided in front of the shank 131. For example, ten grooves are formed in the tool head 134 at equal intervals, and as shown in FIG. 6A, ten bottom blades 140 extending radially from the axial center are provided at the front end of the tool head 134. In addition, as shown in FIG. 6B, ten outer peripheral blades 137 are formed on the side surface of the tool head 134 so as to continue to the bottom blade 140.

JP 2012-161401 A

However, in the round bar described in Patent Document 1, the bottom blade 140 and the outer peripheral blade 137 are rotated from the periosteum to the cortical bone (also referred to as dense bone) and the cancellous bone (by the endometrium in the portion having the medullary cavity). And cancellous bone, bone marrow) can be easily cut, and bone cutting without invasion is difficult.
Specifically, assuming the treatment of intervertebral hernia, the rotating tool head is advanced to cut cortical bone and the like, and the bottom blade is, for example, on the periosteum (hereinafter referred to as the inner periosteum) located on the inner side (close to the spinal canal). When touched, the periosteum is caught by the bottom blade and cut. For this reason, when it is desired to preserve the inner periosteum, it is necessary to stop the cut depth of the round bar immediately before reaching the inner periosteum, and a practitioner or the like is required for skill.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a cutting tool and an instrument for bone surgery that can easily perform bone cutting without invasiveness.

In order to solve the above-mentioned problem, the invention of claim 1 is a cutting tool comprising: a shank to which a rotational force around an axis is applied; and a tool head positioned in front of the shank and contacting a predetermined cutting object. The tool head is formed on an outer peripheral side surface, and an outer peripheral blade that cuts the cutting object by moving the cutting tool in a direction intersecting the axis, and protrudes forward from the outer peripheral blade. , possess a bottom edge without spherically formed the top surface, the outer peripheral blade, wherein formed on the outer peripheral side of the ball-shaped primary processed material constituting the tool head, said top surface, said ball-shaped Among the primary processed materials, the outer peripheral blade is not formed and is formed by a spherical portion .

Invention of Claim 2 is an instrument for bone surgery provided with said cutting tool and the handpiece which attaches | detaches this cutting tool removably and rotates this cutting tool, It is characterized by the above-mentioned. It is.

  According to the present invention, the top surface projects forward from the outer peripheral blade, but since the bottom surface is not provided on the top surface, bone cutting without invasiveness can be easily performed.

It is an external appearance perspective view of the instrument for bone surgery of this invention. It is a top view of the cutting tool of the present invention. It is an enlarged view of the cutting tool of FIG. It is an enlarged view of the cutting tool of FIG. It is a top view of the conventional cutting tool. It is an enlarged view of the cutting tool of FIG.

Hereinafter, the cutting tool and the instrument for bone surgery of the present invention will be described with reference to the drawings. FIG. 1 is an external perspective view of an instrument for bone surgery according to the present invention.
The instrument 1 for bone surgery has a handpiece 2, and the handpiece 2 is connected to the apparatus main body 4 via a cord 3.

For example, a speed adjustment knob 4a is provided on the front surface of the apparatus main body 4, and the apparatus main body 4 is connected to the foot controller 6 via, for example, a cord 5 drawn from the back surface thereof. The speed adjusting knob 4a can adjust the maximum speed when the foot controller 6 is depressed.
The handpiece 2 includes a head portion 21 and a grip portion 22, and a sleeve (not shown) to which the round bar 30 can be detachably attached is provided inside the head portion 21.

  The grip portion 22 is located behind the head portion 21, and a motor (not shown) that drives the sleeve with the power of, for example, a spindle or an AC power source is provided inside the grip portion 22. Thereby, the rotation of the motor is transmitted to the round bar 30 via the spindle and the sleeve. The round bar 30 corresponds to the cutting tool of the present invention. The round bar may be rotated by air instead of the motor.

FIG. 2 is a plan view of the cutting tool of the present invention, and FIGS. 3 and 4 are enlarged views of the cutting tool of FIG. As shown in FIG. 2, the round bar 30 is made of tool steel such as high speed steel, and has, for example, a solid round bar shank 31 attached to the sleeve of the head portion 21 described in FIG. 1. The shank 31 is given a rotational force around the axis from the motor.
In front of the shank 31, for example, a tapered portion 32 that gradually decreases in diameter, a neck portion 33 of a thin shaft, and a tool head 34 that contacts a predetermined cutting object are provided concentrically.

  The tool head 34 is formed in, for example, a ball shape having a larger diameter than the neck portion 33, and the cutting edge is formed by grinding the ball-shaped primary processing material (also referred to as a blank material) with, for example, a grinding wheel. . Specifically, the grinding wheel is tilted with respect to the axis of the tool head 34 and set at a position where it can contact the side surface of the tool head 34. Next, when the grinding wheel is rotated and, for example, the edge of the outer peripheral surface of the grinding wheel comes into contact with the side surface of the tool head 34, when the tool head 34 is advanced at a predetermined speed while being rotated at a predetermined speed, the tool head 34 Is formed with a first groove. Thereafter, when the tool head 34 is rotated by 36 ° to process the second and subsequent grooves in the same manner as described above, a tip portion 38 having no bottom blade is formed.

  More specifically, as shown in FIG. 3A in which the front end of the tool head 34 is enlarged and FIG. 4 which is a perspective view of the tool head 34, the outer peripheral side surface 35 extends radially from the periphery of the tip portion 38. 10 outer peripheral blades 37 are formed, and a spherical surface portion of the primary work material is left at the distal end portion 38. A spherical shape without a bottom blade is provided between the axis of the tool head 34 and the outer peripheral blade 37. The top surface 39 is formed. The outer diameter of the tool head 34 is, for example, about 3 mm to 5 mm.

Further, the top surface 39 projects forward from the front end of the outer peripheral blade 37. Specifically, as shown in FIG. 3B and FIG. 4 in which the side surface of the tool head 34 is enlarged, ten grooves 36 are formed only on the outer peripheral side surface 35 located behind the top surface 39 without a cutting edge, An outer peripheral blade 37 is configured.
Thus, since the top surface 39 remains the spherical surface portion of the primary workpiece, the top surface 39 can be easily manufactured as compared with the case where the top surface is manufactured by polishing a smooth curved surface. And if the round bar 30 of this invention is used, the instrument for bone surgery which can implement bone cutting without an invasion easily can be provided.

For example, an example of unilateral laminectomy for intervertebral hernia will be described. First, the round bar 130 with the bottom blade 140 described in FIG. 5 is set on the handpiece 2, and the round bar 130 is rotated by the power from the motor.
Next, the distal end of the rotated round bar 130 is disposed at one end of the vertebral arch, for example, and advanced, and the periosteum (hereinafter referred to as the outer periosteum) or cortical bone located outside (close to the round bar) with the bottom blade 140, When the cancellous bone is cut and reaches just before the endoperiosteum to be left, the handpiece 2 is pulled up.

  Subsequently, the round bar 130 is removed from the handpiece 2, the round bar 30 of the present invention is set on the handpiece 2, and the front end of the round bar 30 is placed immediately before the endoperiosteum to be left. Then, while rotating the round bar 30 with the power from the motor, the round bar 30 is moved in a direction (for example, the vertical direction) intersecting the axis of the round bar 30 at a position immediately before the periosteum, and the outer periosteum and the cortical bone, Start cutting into cancellous bone.

  In the round bar 30 of the present invention, the top surface 39 protrudes forward from the outer peripheral blade 37, but the top surface 39 is formed in a spherical shape and has no cutting edge. For this reason, even if the front end of the round bar 30 moves forward and the top surface 39 touches the inner periosteum, the inner periosteum is caught on the top surface 39 and is not cut. As a result, the inner periosteum and the like can be easily preserved, and the vertebral arch is opened with the inner periosteum connected to the vertebral body.

  Also, in the treatment of oral tumors and nerve tumors, when it is desired to cut bone while leaving mucous membranes, blood vessels, and tumors, the round bar 130 described with reference to FIG. If the periosteum or cortical bone is cut, and then the round bar 30 of the present invention is set on the handpiece 2 and cutting is started immediately before the tumor, there is no cutting edge at the tip of the round bar 30. Even if the tip advances and the top surface 39 touches the tumor, the tumor is not damaged. Therefore, an incision can be made while leaving the tumor.

  In the above embodiment, a ball-shaped tool head has been described as an example. However, a solid round bar tool head may be used as long as a top surface without a cutting edge is formed. In this case, similarly to the above, bone cutting without invasion can be easily performed.

DESCRIPTION OF SYMBOLS 1 ... Instrument for bone surgery, 2 ... Handpiece, 3 ... Cord, 4 ... Apparatus main body, 4a ... Knob for speed adjustment, 5 ... Cord, 6 ... Foot controller, 21 ... Head part, 22 ... Grip part, 30 DESCRIPTION OF SYMBOLS ... Round bar, 31 ... Shank, 32 ... Tapered part, 33 ... Neck part, 34 ... Tool head, 35 ... Outer peripheral side surface, 36 ... Groove, 37 ... Outer peripheral blade, 38 ... Tip part, 39 ... Top surface.

Claims (2)

A cutting tool comprising a shank to which a rotational force around an axis is applied, and a tool head that is positioned in front of the shank and contacts a predetermined cutting object,
The tool head is
An outer peripheral blade formed on an outer peripheral side surface and cutting the cutting object by moving the cutting tool in a direction intersecting the axis; and
With protruding forward than the outer peripheral edge, it has a spherical shape which is formed in the top surface with no end cutting edge,
The outer peripheral edge is formed on an outer peripheral side surface of a ball-shaped primary work material constituting the tool head, and the top surface is a spherical portion of the ball-shaped primary work material on which the outer peripheral edge is not formed. A cutting tool characterized by being formed .   An instrument for bone surgery comprising: the cutting tool according to claim 1; and a handpiece for detachably mounting the cutting tool and rotating the cutting tool.

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