Sheath for an orthopedic bur and orthopedic bur

Abstract

The utility model relates to medical instrument technical field especially relates to be used for orthopedics milling cutter's sheath and orthopedics milling cutter, sheath includes sheath cap, sheath arm and outer tube, one end of sheath arm is connected with sheath cap, the other end of sheath arm is connected with outer tube, there is gap between sheath cap and outer tube, the gap constitutes milling window, the gap is located in one side of sheath arm, one end of sheath cap is connected with sheath arm, and the end of sheath cap away from sheath arm is gradually reduced pointed top circular arc, the sheath of the utility model, one end of sheath cap adopts pointed top circular arc design, can effectively reduce the interference existing between the top and both sides of conventional square sheath cap, realizes reducing resistance when milling forward, is convenient to take out from the cut seam when reaching the root, effectively avoids secondary injury, the orthopedics milling cutter of the utility model, places the cutter body in the milling window, can realize the milling resection of the bone tissue located in the milling window, protects the other tissues around and avoids the mistake injury.

Description

Technical Field

[0001] This utility model relates to the field of medical device technology, and in particular to a sheath for orthopedic milling cutters and an orthopedic milling cutter. Background Technology

[0002] In orthopedic or related surgical fields such as spine, knee, and neurosurgery, bone cutting end mills are commonly used to mill vertebral lamina, skull plates, or other bone tissues. Optimal milling results are achieved when the end mill tip and the bone tissue are kept as perpendicular as possible. An end mill typically consists of a handle and a shank mounted on the handle. The shank has a circumferentially oriented cutting edge, and a sheath is usually provided on the outer side of the cutting edge.

[0003] In existing orthopedic surgical milling cutters used for cone grooving resection, the sheath structure often leads to increased milling advance resistance, making it inconvenient to remove the cutter from the suture after the milling operation is completed. Utility Model Content

[0004] In view of this, the purpose of this utility model is to provide a sheath for orthopedic milling cutters and an orthopedic milling cutter, so as to at least solve the problem that the sheath structure of existing milling cutters often leads to increased milling advance resistance, making it inconvenient to remove them from the cut after the milling operation.

[0005] This utility model solves the above-mentioned technical problems through the following technical means:

[0006] This utility model provides a sheath for an orthopedic milling cutter, comprising a sheath cap, a sheath arm, and an outer tube. One end of the sheath arm is connected to the sheath cap, and the other end of the sheath arm is connected to the outer tube. There is a notch between the sheath cap and the outer tube, which forms a milling window. The notch is located on one side of the sheath arm. One end of the sheath cap is connected to the sheath arm, and the end of the sheath cap away from the sheath arm is a gradually narrowing pointed arc.

[0007] Furthermore, the radius of the pointed arc is π / 6Rad to π / 3Rad.

[0008] Furthermore, both sides of one end of the outer tube have flat surfaces, and the flat surfaces are located at the end of the outer tube near the sheath arm.

[0009] Furthermore, the sheath cap has a recessed groove on the side facing the milling window, and the distal end of the cutter body in the orthopedic milling cutter is located in the recessed groove.

[0010] The protective sheath of this utility model has a pointed and rounded design at one end of the sheath cap, which can effectively reduce the interference between the top and the two sides of the conventional square sheath cap, reduce resistance when milling forward, and facilitate removal from the cut when reaching the root, effectively avoiding secondary damage.

[0011] Another aspect of this utility model provides an orthopedic milling cutter, including the aforementioned sheath and cutter assembly.

[0012] Furthermore, the tool assembly includes a fixedly connected tool body and tool holder. The tool body is located at the milling window. The outer periphery of the tool body is provided with double straight cutting edges. The double straight cutting edges include two cutting blades that are centrally symmetrical about the center line of the tool body. The cutting blades include side straight cutting edges and a clearance surface. The clearance surface is a smooth arc-shaped surface.

[0013] Furthermore, the cutting edge also includes a front cutting face and a rear cutting face. The front cutting face is a straight surface and is perpendicular to the blade body. The intersection line between the rear cutting face and the front cutting face forms a side straight edge.

[0014] Furthermore, the avoidance surface and the back cutter face are smoothly connected.

[0015] Furthermore, the angle between the flank face and the rake face is an acute angle, and the angle between the flank face and the clearance face is an obtuse angle.

[0016] This orthopedic milling cutter features a double straight-edged design. On one hand, the unidirectional rotation of the cutter body allows for efficient bone removal and milling to remove thicker bone sections by creating a grooving cut. On the other hand, the smooth avoidance surface and side straight edges cause minimal damage to soft tissue, ensuring safe use. Placing the cutter body within the milling window allows for the milling removal of bone tissue within that window, protecting surrounding tissues from accidental injury. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of the protective sheath for orthopedic milling cutters according to this utility model;

[0018] Figure 2 This is a schematic diagram of the orthopedic milling cutter of this utility model;

[0019] Figure 3 yes Figure 2 Enlarged structural diagram at point A;

[0020] Figure 4 This is an enlarged structural diagram of the distal end of an orthopedic milling cutter;

[0021] Figure 5 This is an enlarged structural schematic diagram of the tool assembly;

[0022] Among them, the sheath 100, sheath cap 110, pointed arc 111, sheath arm 120, outer tube 130, flat surface 131, milling window 140, tool assembly 200, tool body 210, side straight edge 211, clearance surface 212, front cutting face 213, back cutting face 214, chip removal groove 215, tool holder 220, and handle 300. Detailed Implementation

[0023] The following specific embodiments illustrate the implementation of this utility model. Those skilled in the art can understand the advantages and effects of this utility model from the content disclosed in this specification. It should be noted that the illustrations provided in the following embodiments are for illustrative purposes only and represent schematic diagrams, not actual pictures. They should not be construed as limiting the utility model. To better illustrate the embodiments of this utility model, some components in the figures may be omitted, enlarged, or reduced, and do not represent the actual product dimensions. It is understandable that some well-known structures and their descriptions may be omitted in the figures for those skilled in the art.

[0024] In the figures of this utility model embodiment, the same or similar reference numerals correspond to the same or similar components. In the description of this utility model, it should be understood that if terms such as "upper", "lower", "left", "right", "front", "rear", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the figure, they are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms used to describe the positional relationship in the figure are only for illustrative purposes and should not be construed as limiting this utility model. For those skilled in the art, the specific meaning of the above-mentioned terms can be understood according to the specific circumstances.

[0025] In vertebral body resection surgery, the lamina is first ground down with a drill bit until a layer of bone less than 2mm remains at the bottom of the groove. This remaining bone is then removed using manual lamina forceps to complete the surgery. If the remaining bone thickness after drilling is too thick, it becomes difficult to use manual forceps, and the process requires painstakingly removing the remaining bone bit by bit, resulting in low efficiency. Furthermore, the sheath structure of existing orthopedic surgical milling cutters used in vertebral body resection surgery often increases the resistance to milling, making it difficult to remove from the suture after the milling procedure.

[0026] To address this, this application proposes a sheath for an orthopedic milling cutter. One end of the sheath cap is a gradually tapering, pointed arc shape, effectively reducing interference between the top and sides of a conventional square sheath cap. This reduces resistance during milling and facilitates easy removal from the cut when reaching the root, effectively preventing secondary injury. Furthermore, this application also proposes an orthopedic milling cutter, including the aforementioned sheath and a cutting tool assembly. The cutting tool assembly has double straight cutting edges on the outer periphery of the cutter body, used to replace manual laminectomy forceps for efficient resection.

[0027] In this application, the distal end refers to the end furthest from the hand-held part, and the proximal end refers to the end closest to the hand-held part.

[0028] To better understand the above technical solutions, the following will provide a detailed explanation of the technical solutions in conjunction with the accompanying drawings and specific implementation methods.

[0029] Please refer to Figure 1 In one embodiment, the sheath 100 for orthopedic milling cutters of this application includes a sheath cap 110, a sheath arm 120, and an outer tube 130. One end of the sheath arm 120 is fixedly connected to the sheath cap 110, and the other end of the sheath arm 120 is fixedly connected to the outer tube 130. A notch is provided between the sheath cap 110 and the outer tube 130, forming a milling window 140. The notch is located on one side of the sheath arm 120. One end of the sheath cap 110 is fixedly connected to the sheath arm 120, and the end of the sheath cap 110 away from the sheath arm 120 is a gradually tapering pointed arc 111.

[0030] The pointed, rounded design at one end of the sheath cap 110 effectively reduces interference between the top and sides of a conventional square sheath cap, reducing resistance during milling and facilitating removal from the kerf when reaching the root, thus effectively preventing secondary damage.

[0031] To reduce resistance during milling while still providing the protective function of the sheath 100, the radius of the pointed arc 111 is π / 6 Rad to π / 3 Rad, i.e. Figure 4 The value of α in the equation ranges from π / 6Rad to π / 3Rad.

[0032] To allow the distal end of the orthopedic end mill with the sheath 100 to better enter the conical slot position (the position to be milled), both opposite sides of one end of the outer tube 130 have flat surfaces 131, located at the end of the outer tube 130 near the sheath arm 120. The flat surfaces 131 on opposite sides of the outer tube 130 near the sheath arm 120 form a non-cylindrical structure, providing clearance on both sides of the outer tube 130 near the sheath arm 120, which facilitates the distal end of the orthopedic end mill entering narrow slit spaces for milling operations.

[0033] The sheath cap 110 has a relief groove (not shown) on the side facing the milling window 140, and the distal end of the cutter body in the orthopedic milling cutter is located in the relief groove to protect the distal end of the cutter body.

[0034] Please refer to Figures 2-5 In another embodiment, this application also provides an orthopedic end mill, including the aforementioned sheath 100, cutter assembly 200, and handle 300. For example... Figure 5As shown, the tool assembly 200 includes a fixedly connected tool body 210 and tool holder 220. The tool body 210 is located at the milling window 140. A double straight cutting edge is provided on the outer periphery of the tool body 210. The double straight cutting edge includes two cutting edges that are centrally symmetrical about the center line of the tool body 210. Each cutting edge includes a side straight cutting edge 211 and a clearance surface 212, the clearance surface 212 being a smooth arc surface. The cutting edge also includes a rake face 213 and a flank face 214. The rake face 213 is a straight surface and perpendicular to the tool body 210; the intersection line between the flank face 214 and the rake face 213 forms the side straight cutting edge 211. The clearance surface 212 and the flank face 214 are smoothly connected. The included angle between the flank face 214 and the rake face 213 is an acute angle, and the included angle between the flank face 214 and the clearance surface 212 is an obtuse angle.

[0035] A rake face 213 is ground perpendicular to the tool body 210 using a grinding machine. Then, the tool body 210 is rotated 180° and the other rake face 213 is ground in the same manner. Next, the flank face 214 is machined by clamping the tool body 210 and rotating it back and forth 120°-160° to grind the flank face 214 and the tool clearance surface 212. During machining, the angle of rotation of the tool body 210 is limited to prevent damage to the opposite straight cutting edge 211. A right-angled notch is formed between the two cutting edges as a chip removal groove 215, with a right-angled cross-section. Using this machining method, the rake face 213, flank face 214, and clearance surface 212 can be stably machined, ensuring a relatively sharp side straight cutting edge 211 with almost no burrs. The difference in cutting edge between the two side straight cutting edges 211 can be less than 0.02mm.

[0036] The handle 220 passes through the outer tube 130 and connects to the transmission component inside the handle 300. The transmission component is connected to the output shaft of the motor. The unidirectional rotation of the motor drives the handle 220 to rotate in one direction via the transmission component, which in turn causes the blade 210 to rotate in one direction, thereby achieving milling and removal of bone tissue. The transmission component adopts a conventional transmission structure, such as a coupling or gear transmission structure. This application does not impose specific limitations, as long as the transmission between the motor and the handle 220 can be achieved. In use, the milling window 140 is aligned with the bone to be milled, the side straight blade 211 contacts the bone tissue, and the motor is turned on to drive the blade 210 to rotate, thereby removing the bone within the milling window 140.

[0037] Employing a double straight-blade design, the blade 210's unidirectional rotation enables efficient bone removal and allows for milling and grooving to remove excessively thick bone. Furthermore, the smooth avoidance surface 212 and the side straight blade 211 cause minimal damage to soft tissue, ensuring safe use. Placing the blade 210 within the milling window 140 allows for milling and removal of bone tissue within this window, protecting surrounding tissues from injury. Specifically, the sheath cap 110 protects the tissue anterior to the distal end of the blade 210, while the sheath arm 120 protects the tissue on the sides of the blade 210.

[0038] The above embodiments are only used to illustrate the technical solutions of this utility model and are not intended to limit it. Although this utility model has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of this utility model without departing from the spirit and scope of the technical solutions of this utility model, and all such modifications and substitutions should be covered within the scope of the claims of this utility model. Technologies, shapes, and structural parts not described in detail in this utility model are all known technologies.

Claims

1. A sheath for orthopedic milling cutters, characterized in that, The device includes a sheath cap, a sheath arm, and an outer tube. One end of the sheath arm is connected to the sheath cap, and the other end of the sheath arm is connected to the outer tube. There is a notch between the sheath cap and the outer tube, which forms a milling window. The notch is located on one side of the sheath arm. One end of the sheath cap is connected to the sheath arm, and the end of the sheath cap away from the sheath arm is a gradually narrowing pointed arc with an arc radius of π / 6 Rad to π / 3 Rad. The outer tube has flat surfaces on both opposite sides at one end, and the flat surfaces are located at the end of the outer tube closer to the sheath arm.

2. The sheath for orthopedic milling cutters according to claim 1, characterized in that, The sheath cap has a recessed groove on the side facing the milling window, and the distal end of the cutter body in the orthopedic milling cutter is located in the recessed groove.

3. An orthopedic end mill, characterized in that, Includes the sheath and knife assembly as described in any one of claims 1-2.

4. The orthopedic end mill according to claim 3, characterized in that, The tool assembly includes a fixedly connected tool body and tool holder. The tool body is located at the milling window. The outer periphery of the tool body is provided with double straight cutting edges. The double straight cutting edges include two cutting edges that are centrally symmetrical about the center line of the tool body. The cutting edges include side straight cutting edges and a clearance surface. The clearance surface is a smooth arc-shaped surface.

5. The orthopedic end mill according to claim 4, characterized in that, The cutting edge also includes a front cutting face and a rear cutting face. The front cutting face is a straight surface and is perpendicular to the blade body. The intersection line between the rear cutting face and the front cutting face forms a side straight edge.

6. The orthopedic end mill according to claim 5, characterized in that, The avoidance surface and the back cutting surface are smoothly connected.

7. The orthopedic end mill according to claim 6, characterized in that, The angle between the flank face and the rake face is acute, and the angle between the flank face and the clearance face is obtuse.

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