JP4288322B2 - Osteosynthesis tool - Google Patents

Description

  The present invention relates to an osteosynthesis tool for embedding an osteosynthesis screw used to fix a bone during osteosynthesis in a fracture portion.

In osteosynthesis, a technique of fixing a bone by embedding a metal osteosynthesis screw such as titanium in a fracture part is generally performed, and a special metal screw used for this purpose or this screw is used. A driver for use in the application has been filed (Patent Document 1).
However, because metals in the body can corrode and provide a risk of infection, a reoperation to remove the metal screw is required after the bone has healed. It will impose a mental and physical burden.

  If you create an osteosynthesis screw with a bioabsorbable material (for example, bone, artificial bone, bioabsorbable polymer) that integrates with the surrounding bone in vivo and eventually replaces normal bone, There is no need to re-operate and remove the bone screw after the bone has healed, greatly reducing the burden on the patient.

However, since the screw formed of the material as described above has a lower shear strength than metal, when the screwing torque at the time of screw insertion is increased, a vertical crack is generated in the screw head and is easily broken.
Also, depending on the site to be operated, the screw may be embedded in the fractured part in a deep and narrow working space, and at this time it may be difficult to hold the fitting part of the screw and the driver by hand, or it may not be held, Camout phenomenon that the head of the screw collapses easily occurs, and workability is poor.
JP 10-272142 A

  Provided is an osteosynthesis tool that can prevent problems such as vertical cracks and camouts that occur when a fragile screw made of a material having low shear strength is screwed in, and can securely fix the screw at a predetermined position.

  In order to solve the above-mentioned problem, as described in claim 1, a driver that engages with the head of an osteosynthesis screw to be screwed into a bone is provided, and the tip of the driver is formed to have the same diameter as the osteosynthesis screw. A screw having the same shape as the osteosynthesis screw is formed on the outer periphery of the tip, and a long nut is provided to be engaged with both the osteosynthesis screw and the screw at the tip of the driver. And a socket tube to be mounted on the outer periphery of the driver. A spline groove to be fitted to the long nut is formed inside the opening of the socket tube. The long nut can be swung or fixed by fitting the spline groove of the socket cylinder to the long nut so as to be slidable in the length direction and pivotable around the driver.

  As described in claim 2, the long nut is formed of a light transmissive material.

  According to a third aspect of the present invention, a screwless portion without a screw is formed at the tip of the driver.

  5. An embedded groove along the length direction of the driver is formed in the driver as described in claim 4, a thin wire-like projecting body is accommodated in the driver, the projecting body is advanced, and an osteosynthesis screw is formed at the distal end of the projecting body. The head and the bone screw were separated from each other.

  As described in claim 1, the tip portion of the driver is formed to have the same diameter as the screw, and a screw having the same shape as the osteosynthesis screw is formed on the outer periphery of the tip portion, and both the osteosynthesis screw and the screw of the driver tip portion are formed. By providing a long nut to be screwed together, the osteosynthesis screw and the driver are integrally connected via the long nut to prevent a cam-out phenomenon and use it in a narrow space where the osteosynthesis screw cannot be held by hand. In addition, since the head of the osteosynthesis screw is in close contact with the long nut, vertical cracking of the screw can also be prevented.

  Since the long nut is formed of a light-transmitting material as described in claim 2, the workability is improved because the work can be performed while observing the engagement state and the engagement position between the screw and the driver.

  According to the third aspect of the present invention, since the screwless portion without the screw is formed on the peripheral surface of the tip of the driver, the tip of the driver is not screwed even if the screw is embedded in the fracture portion using the embedded screw. The driver can be pulled out by releasing the engagement state between the driver and the screw.

  5. A screwdriver that is firmly engaged with a screw by providing a separating mechanism that slidably accommodates a protruding body in an embedded groove formed in the driver and projects the head of the screw to separate it from the driver. This prevents the screw from coming out of the installation area and forcing the screwdriver to damage the screw head.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a partial cross-sectional view of an osteosynthesis tool 1 according to the present invention. The osteosynthesis tool 1 includes a driver 2, a long nut 3 and a grip 4. In the figure, the long nut 3 and the grip 4 are shown in cross section.
The driver 2 includes a driver bit portion 6 and a handle portion 7, and the driver bit portion 6 and the handle portion 7 are configured integrally or detachably. The driver 2 is slidably inserted into a substantially cylindrical grip 4.

  FIG. 2 is an enlarged side view of the driver bit unit 6. An engaging portion 11 with a screw is provided at the tip of the driver bit portion 6. Here, the driver bit part 6 provided with the minus type engaging part 11 is shown. Further, a male thread portion 8 is formed by providing a thread on the peripheral surface of the tip portion of the driver bit portion 6. At this time, a defect portion 10 that does not form a screw thread by a predetermined distance from the tip of the driver bit portion 6 is provided. The length of the defect 10 is, for example, about 1 mm to 4 mm.

  FIG. 3 is a perspective view showing a screw that is screwed into a fracture portion in order to fix the fractured bone. Here, the screw is a set screw 9, a thread is formed on the circumferential surface over the entire length, and a slit is formed as the engaged portion 12 on the head. The set screw 9 has the same diameter as the tip of the driver bit portion 6 and has the same pitch as the thread provided on the male screw portion 8.

In addition to the minus type, the screwdriver 2 and screw are engaged in special shapes such as plus and Torx (registered trademark), polygons such as square and hexagon, ellipses and semicircles, etc. If it is.
Such implantable screws are used for intra-articular fractures where head protrusion is a problem.

  The long nut 3 is screwed into both the male screw portion 8 and the set screw 9 of the driver bit portion 6 so that the driver 2 and the set screw 9 are connected. The long nut 3 may be formed of, for example, polycarbonate or glass having light transmittance.

  FIG. 4 is a perspective view of the grip 4. The grip 4 has a substantially cylindrical shape, and the driver 2 is slidably mounted. A socket cylinder 5 having a spline groove is formed on the distal end side, and the grip 4 is slid so that the long nut 3 screwed into the male threaded portion 8 of the driver bit portion 6 can be fitted.

  For example, as shown in FIG. 5, when the long nut 3 is a hexagonal nut, the socket tube 5 is a hexagonal shape or a hex lobe type. Can also take the shape of a polygon such as a triangle or a rectangle, or an ellipse or a semicircle.

  The osteosynthesis tool constructed as described above is engaged with the male screw portion 8 formed on the driver bit portion 6 by first engaging the screw with the engaging portion 11 of the driver bit portion 6 with the driver 2 inserted through the grip 4. The long nut 3 is screwed to both the combined screws, and the driver 2 and the screws are connected.

  Next, the tip of the screw is filled in the place where the fracture is to be embedded, and the screwdriver is screwed by rotating the driver 2. When the long nut 3 reaches the fracture surface, as shown in FIG. 6, the grip 4 is slid to fit the socket cylinder 5 into the long nut 3, and the driver 2 is rotated while gripping the grip 4. Screw the screw to the desired position.

  When the socket cylinder 5 is fitted to the long nut 3 that has been screwed together with the screw by the rotation of the driver 2, the rotation of the long nut 3 is restricted because the grip 4 is gripped. Only the screw is screwed by the rotation of the driver 2 and screwed into the fracture portion.

  In this embodiment, since the screw is a set screw 9, it can be embedded in the bone. Although the screw is screwed into the fracture portion and the driver bit portion 6 also enters the bone, the tip portion of the driver bit portion 6 is provided with a defect portion 10 that does not form a screw thread, so that the screw is screwed to a desired depth. Even if screwed, the driver 2 can be pulled out without screwing with the fractured part.

  When connecting the screwdriver 2 and the screw, if the long nut 3 is formed of a material having optical transparency, the engagement position and the engagement state can be visually checked, so that workability is good. Further, for example, when the long nut 3 is made of polycarbonate having light transmission properties, the polycarbonate has elasticity, so that it is difficult to break the screw thread by screwing in an appropriate state with the screw. Further, when the long nut 3 is formed of glass, the long nut 3 is obtained which is transparent and has an easy-to-see engaging portion and excellent workability.

  In addition, since the osteosynthesis screw and the driver are integrally connected via the long nut, it can be used in a narrow space where the osteosynthesis screw cannot be held by hand, preventing the camout phenomenon. Since the head of this is in close contact with the long nut, it is possible to prevent vertical cracking of the screw.

  Next, a second embodiment of the screw will be described in detail with reference to FIGS. FIG. 7 is a perspective view showing a second embodiment of the screw. In this embodiment, the screw is a bolt screw 9a, and a male screw 13 is formed on the head of the bolt screw 9a. The male screw 13 on the head has a thread having the same diameter as the tip of the driver bit portion 6 and the same pitch as the male screw portion 8.

  In the case of the bolt screw 9a of the present embodiment, the bolt screw 9a is screwed into the fracture portion, the long nut 3 reaches the fracture portion surface, and the socket cylinder 5 is fitted to the long nut 3 as shown in FIG. Further, the driver 2 is rotated and the screw is fastened, and the screw 2 is rotated in the direction opposite to the rotation direction of the driver 2 while the driver 2 is fixed, and the long nut 3 is screwed in the direction opposite to the traveling direction of the bolt screw 9a. The long nut 3 and the bolt screw 9a are unscrewed.

  Next, a second embodiment of the osteosynthesis tool will be described in detail with reference to FIGS. 9 to 16. FIG. 9 is a side view of the second embodiment of the osteosynthesis tool. In the present embodiment, the osteosynthesis tool 1 has a separation mechanism 14. The separation mechanism 14 is formed with an embedded groove 15 in the length direction of the driver 2, and a thin wire-like protruding body 16 is slidably mounted in the embedded groove 15. It is comprised so that it may protrude from the front-end | tip of 2.

The embedded groove 15 is formed with one or a plurality of groove holes 17 in the axial direction of the driver bit portion 6. In this embodiment, as shown in FIG. 10, two groove holes 17 are provided so as to equally divide the circumference of the driver bit portion 6, and both slits 18 are provided on the handle portion 7 side of the groove hole 17. The groove 17 is connected to form a buried groove 15.
The slot 17 is formed so as not to interfere with the engaging portion 11. In the present embodiment, the embedded groove 15 is formed by providing the groove hole 17 at a position orthogonal to the direction of the minus blade of the driver 2 having the minus type engaging portion 11.

  FIG. 11 is a perspective view of the protruding body 16 in the present embodiment. The protruding body 16 has a tip 19 formed in a bifurcated manner in accordance with the embodiment of the embedded groove 15. One of the tips 19 is attached to the driver 2 through the slit 18, and the tips 19 are respectively positioned on the slots 17. The protruding body 16 can be slid by the length of the slit 18. When the protruding body 16 is slid, the tip 19 protrudes from the tip of the driver 2.

  FIG. 12 is a cross-sectional view of the osteosynthesis tool of this embodiment. A long nut 3 is screwed and connected to a screw 9 and a male screw portion 8 formed at the tip of the driver 2 locked to the screw 9, and a grip 4 having a socket cylinder 5 in which a spline groove is formed is attached. The body 15 is attached to the slot 17 and the slit 18 formed along the length direction of the driver 2. The grip 4 is formed short so that the protruding body 15 and the grip 4 do not interfere with each other.

  As shown in FIG. 12, the separation mechanism 14 of the present embodiment is used when the screw 2 is screwed and then the screw 2 is released by releasing the engagement between the screw and the driver 2. Since it may be difficult to pull out the driver 2 depending on the engagement state between the driver 2 and the screw, at this time, the protruding body 16 is slid and the tip 19 is protruded from the tip of the driver 2 so as to contact the head of the screw. Pull out the driver 2 while holding the screw head.

  The osteosynthesis tool according to the present embodiment is firmly attached to the screw by providing a separation mechanism that protrudes into the embedded groove formed in the driver and slidably accommodates the body and projects the head of the screw to separate it from the driver. It is possible to prevent the screw from being pulled out of the installation portion by forcibly removing the engaged driver or damaging the screw head by twisting the driver.

Hereinafter, the second and third embodiments of the separation mechanism will be described with reference to FIGS. 13 to 14 and FIGS. 15 to 16, respectively.
FIG. 13 is a front view of the driver bit unit 6 showing a second embodiment of the separation mechanism 14. In this embodiment, the embedded groove 15 is formed by providing a slit-like groove hole 17a in a direction perpendicular to the minus blade of the driver 2 at the center of the driver 2, and the groove hole 17a has, for example, as shown in FIG. The protruding body 16 is mounted through the slit 18.

  FIG. 15 is a front view of the driver bit unit 6 showing a third embodiment of the separation mechanism 14. In this embodiment, the engaging portion 11 of the driver is a hexagonal shape, and the embedded groove 15 is formed by providing a groove hole 17b in the center of the driver 2, and the groove hole 17b protrudes as shown in FIG. The body 16 is attached through the slit 18.

Partial cross-sectional view of osteosynthesis tool Enlarged side view of the driver bit Screw perspective view Grip perspective view AA sectional view of FIG. Partial sectional view of osteosynthesis tool with sliding grip The perspective view which shows 2nd Embodiment of a screw Partial sectional view of the osteosynthesis tool according to the second embodiment of the screw Side view of second embodiment of osteosynthesis tool Front view of the tip of the driver bit Perspective view of pusher Partial sectional view of the second embodiment of the osteosynthesis tool Front view of the driver bit portion of the second embodiment of the separation mechanism The perspective view of the pushing tool concerning 2nd Embodiment of a separation mechanism. Front view of the driver bit portion of the third embodiment of the separation mechanism The perspective view of the pushing tool concerning 3rd Embodiment of a separation mechanism.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Osteotomy tool 2 Driver 3 Long nut 4 Grip 5 Socket cylinder 6 Driver bit part 7 Handle part 8 Male screw part 9 Set screw 9a Bolt screw 10 Deletion part 11 Engagement part 12 Engagement part 13 Male screw 14 Detachment mechanism 15 Implantation Groove 16 Projecting body 17 Groove hole 18 Slit 19 Tip

Claims (4)

A screwdriver that engages the head of the bone screw to be screwed into the bone is provided, and the tip of this driver is formed to have the same diameter as that of the bone screw, and a screw having the same shape as the bone screw is formed around the tip And
Then, a long nut that is screwed to both the osteosynthesis screw and the screw at the tip of the driver is provided, and the osteosynthesis screw and the driver are integrally connected through the long nut,
Furthermore, a socket tube to be mounted on the outer periphery of the driver is provided, and a spline groove to be fitted to the long nut is formed on the inside of the tip opening of the socket tube,
The socket cylinder is slidable in the longitudinal direction with respect to the driver and pivotable about the driver, so that the spline groove of the socket cylinder is fitted to the long nut so that the long nut is pivoted or fixed. An osteosynthesis tool.   The osteosynthesis tool according to claim 1, wherein the long nut is formed of a light-transmitting material.   The osteosynthesis tool according to claim 1, wherein a screwless part without a screw is formed at a tip part of the driver.   An embedding groove along the length direction is formed in the driver, a thin wire-like protruding body is accommodated in the driver, the protruding body is advanced, and the head of the osteosynthesis screw is protruded at the tip of the protruding body. The osteosynthesis tool according to claim 1, wherein the screwdriver and the osteosynthesis screw are separated.

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