JP4737595B2 - Manufacturing method of osteosynthesis screw - Google Patents

Description

The present invention relates to a method of manufacturing an osteosynthesis screw used in osteosynthesis for treating an exfoliation fracture or the like.

  In osteosynthesis for treating an exfoliation fracture or the like, a technique of fixing a bone by embedding a metal osteosynthesis screw such as titanium in a fracture part is generally performed. On the other hand, if a metal osteosynthesis screw is embedded in the living body, the metal screw may corrode or provide an infection site. Re-operation was required to remove it. However, re-surgery puts the patient at risk of anesthesia and the mental and physical burden.

  A material that can be integrated with the surrounding bones in the living body and eventually replaced with normal bones, such as the patient's own bone, and a bone joint screw made of this bone fragment. Since it is not necessary to remove the osteosynthesis screw embedded in the fractured part after re-operation, the burden on the patient can be greatly reduced.

  By the way, the applicant has already filed an application for a spindle head having a simple structure and a reduced size (Patent Document 1). The small lathe device constructed using this headstock is simple in structure, so it is easy to disinfect the chuck claws that the bone fragment touches, and this lathe device can be placed in a hospital operating room or in a nearby room. It can be used for processing.

However, the bone has a dense structure inside, and there are hard and soft parts mixed together, so if it is processed using a conventional lathe device, it will dry due to frictional heat and become partially brittle, etc. There was a risk that the bone fragment would break inside.
JP 2002-337036 A

The problem to be solved is that when machining with a conventional lathe device, the bone fragment may be broken during threading, and the present invention performs threading without breaking the brittle bone fragment. It is an object of the present invention to provide a method for manufacturing an osteosynthesis screw .

In order to solve the above-mentioned problem, as described in claim 1, the base is provided with a main shaft that is slidable in the axial direction and a bite that slides along the main shaft, and a bone at the lower end of the main shaft. A chuck device for gripping the piece is attached, a bathtub having an open upper surface is provided below the main shaft to fill the liquid, and the chuck device is configured to enter and exit the bathtub ,
After immersing bone fragments in the liquid in the bathtub and making the surface easy to cut,
A bone fragment is taken out from the liquid in the bathtub and processed into a cylindrical shape, and then threaded .

As described in claim 2, the liquid is an aqueous solution selected from the group consisting of ethanol, acetic acid, sodium hydroxide, EDTA, and formaldehyde.

As described in claim 3, after the liquid is a hyaluronic acid aqueous solution and the bone fragment is immersed in the hyaluronic acid aqueous solution of the bathtub, the liquid is taken out from the bathtub and cooled, and after freezing the surface of the bone fragment, Cylindrical processing and threading are sequentially performed.

According to a fourth aspect of the present invention, the base is provided with a main shaft that is slidable in the axial direction in the longitudinal direction and a tool that slides along the main shaft, and a chuck device that holds a bone fragment is attached to the lower end of the main shaft. , A bathtub having an open top surface is provided below the main shaft to fill the liquid, and the chuck device is configured to freely enter and exit the bathtub,
The liquid is an aqueous solution of any one of the group consisting of ethanol, acetic acid, sodium hydroxide, EDTA or formaldehyde;
After immersing bone fragments in the aqueous solution to make the surface easy to cut, the bone fragments are removed from the bathtub and washed after columnar processing, and the liquid in the bathtub is replaced with physiological saline or hyaluronic acid aqueous solution.
The washed bone piece is immersed in the bathtub and threaded.

As described in claim 1, after immersing bone fragments in a liquid in a bathtub and making the surface easy to cut,
Since the bone fragment is taken out from the liquid in the bathtub and processed into a cylindrical shape and then threaded, the surface of the bone fragment can be easily cut and can be reliably processed without breaking the bone fragment.

As described in claim 2 , after immersing bone fragments in an aqueous solution of any one of the group consisting of ethanol, acetic acid, sodium hydroxide, EDTA or formaldehyde, the cylindrical processing and threading processing are taken out from the aqueous solution. Therefore, the surface of the bone fragment can be easily cut and processed, and the burden on the bone fragment during cutting can be reduced to prevent the bone fragment from being broken .

As described in claim 3, the bone fragments are immersed in a hyaluronic acid aqueous solution and then taken out, cooled and frozen, so that the rough structure of the bone fragments is leveled and the bone fragments are prevented from breaking during cutting. it can.

5. A bone fragment after being processed into a columnar shape in a state where the bone fragment is immersed in an aqueous solution of any one of the group consisting of ethanol, acetic acid, sodium hydroxide, EDTA or formaldehyde, and taken out from the aqueous solution, as described in claim 4. And then threaded by immersing in physiological saline or hyaluronic acid aqueous solution, so that the surface of the bone fragment can be easily machined and processed into a cylindrical shape. Drying by exposure is prevented, and the bone pieces can be threaded with sufficient moisture and elasticity.

Hereinafter, the configuration of the vertical lathe used in the present invention will be described with reference to FIGS. FIG. 1 is an overall front view of a vertical lathe used in the present invention, and FIG. 2 is an overall side view of the vertical lathe.

  The vertical lathe 1 includes a base 2, a support part 3 erected upward from the side of the base 2, a headstock 4 attached to the support part 3 so as to be vertically adjustable, and A turret 5 that is attached to the headstock 4 and is slidably mounted along the main spindle, a bathtub 6 that is provided on the base 2 and is arranged below the headstock 4 and the tool rest 5, and in the bathtub 6 The tailstock 7 and the heater 8 are provided.

  The support portion 3 is formed integrally with the base 2 or is integrally formed by fastening and fixing to the side portion of the base 2 with a bolt or the like, and is erected upward. A sliding mechanism is provided on the base 2 side of the support portion 3. The sliding mechanism in the present embodiment is provided with a pair of V-groove linear guide portions 30 parallel to each other, forming a hollow portion 31 between them, and providing bearing portions 32 at the upper and lower ends of the hollow portion 31, A feed screw rod 33 is rotatably attached by the bearing portion 32, the feed screw rod 33 is connected to a servo motor 34 provided at the upper end of the support portion 3, and the feed screw rod 33 is rotationally driven by the servo motor 34. It is formed.

  The support portion 3 is provided with two sets of sliding portions. In this embodiment, the head stock 4 is attached to the right side as viewed from the front, and the tool post 5 is attached to the left side. The headstock 4 and the tool rest 5 are respectively attached to the feed screw rod 33 and supported by two V-groove linear guide portions 30 across the hollow portion 31 and slide according to the rotation of the feed screw rod 33. To do.

  The headstock 4 is provided with a small motor 40, and the main shaft 41 is connected to the output shaft of the motor 40 and attached in a vertical direction. A chuck 42 for holding a bone fragment is attached to the lower end of the main shaft 41.

  The tool post 5 includes an X-axis guide 52 slidable in the X-axis direction (front view left-right direction). Four arms 50 are attached to the X-axis guide 52 and extended downward, and the cutting tool 51 is fixed by sandwiching two portions on the blade side and the rear end side from the left and right sides as viewed from the side.

  A bathtub 6 is provided below the headstock 4 and the tool post 5. The bathtub 6 is detachably attached to the base 2. A tailstock 7 and a heater 8 are provided in the bathtub 6, and a tailstock 70 is provided on the tailstock 7 so as to face the main shaft 41 and coaxially. The mandrel 70 is configured to be adjustable in height. The bath 6 is filled with liquids for lubrication, heat retention or cooling, and the heater 8 is used to warm or heat these liquids.

  The liquid filled in the bath 6 is, for example, physiological saline, hyaluronic acid aqueous solution, 50 to 100 v / v% (volume percentage) ethanol, 1 to 20 v / v% acetic acid, 0.1 to 10 N hydrochloric acid, 0.1 to 2 Normal sodium hydroxide, 0.1 to 0.5 M (molar concentration) EDTA (ethylenediaminetetraacetic acid), 1 to 10 w / v (weight to volume percentage)% formaldehyde, and the like.

  In the present embodiment, the main shaft 41 of the vertical lathe 1 is arranged in a substantially vertical direction, but may be arranged so as to be inclined obliquely from the vertical direction. When the main shaft 41 is arranged obliquely, the sliding direction of the tool post 5 is also inclined along the main shaft 41, the sliding direction of the X-axis guide 52 is changed to a direction perpendicular to the main shaft 41, and a tailstock bar 70 is also arranged coaxially with the main shaft 41.

Then for the use of vertical lathe 1 configured as described will be described threading creating bone screws from the bone pieces.

The bone fragment to be cut out is an indeterminate rod shape having a length of about 10 to 40 mm and about 3 to 8 mm square. This bone fragment is attached to and gripped by a chuck 42 provided at the lower end of the main shaft 41, the servo motor 34 is driven to slide the main shaft base 4 downward, and the bone fragment is immersed in a liquid filled in the bathtub 6. The tip of the bone piece is brought into contact with the tailstock 70. Next, the tool post 5 is slid downward, the arm 50 is slid by the X-axis guide 52, and the cutting tool 51 is brought into contact with the bone fragment. Then, the bone piece is first processed into a cylindrical shape having a diameter of about 3 to 8 mm, and then the bone piece is threaded .

  When the bathtub 6 is filled with a hyaluronic acid aqueous solution, a cooling bath may be provided around the bathtub 6 and filled with ice, liquid nitrogen, or the like, and the hyaluronic acid aqueous solution may be cooled to a low temperature. In this case, after infiltrating hyaluronic acid into the intravascular bone part of the bone fragment, the bone fragment is pulled out of the liquid, cooled with liquid nitrogen or the like, and frozen. By filling hyaluronic acid in a rough part such as a blood vessel part of a bone fragment and freezing, the rough structure of the bone fragment can be leveled and the bone fragment can be prevented from being broken during cutting.

  Further, when the bathtub 6 is filled with ethanol, acetic acid, sodium hydroxide, EDTA or formaldehyde, the process of forming the bone fragment into a cylindrical shape and the threading process are performed by immersing the bone fragment in the bathtub 6 for a predetermined time and then servoing. The motor 34 is driven to slide the headstock 4 upward and the tailstock rod 70 extends upward, and the bone fragments are pulled up from the liquid.

  In these liquids, ethanol, acetic acid, sodium hydroxide and formaldehyde have a protein modifying action, EDTA has a decalcifying action, and hydrochloric acid has a protein modifying action and a decalcifying action. Therefore, by immersing bone fragments in these, only the surface portion of the bone fragments is denatured or decalcified, thereby making the surface of the bone fragments easy to process and processing, and the burden on the bone fragments during cutting is reduced. Less can prevent the bone fragment from being broken.

  When processing bone fragments, these liquids can also be used in combination. For example, when processing to form a bone fragment into a columnar shape, the bathtub 6 is filled with ethanol, acetic acid, sodium hydroxide, EDTA, formaldehyde, or the like to easily cut the surface of the bone fragment, and then perform the processing quickly. 6 is replaced or removed and washed, filled with physiological saline or hyaluronic acid aqueous solution, and bone pieces are threaded.

  Since the bone fragments have various shapes and irregular shapes, and have individual differences, the bone fragments are filled with various kinds of liquids as described above, and the bone fragments can be processed in various atmospheres. Thus, an appropriate liquid can be selected according to the state of the bone, and the bone piece can be reliably processed without breaking.

  Further, the vertical lathe 1 is provided with an encoder (not shown) and an input / output unit (not shown) for detecting the rotation angle of the spindle 41 and the feed screw rod 33 on the spindle stock 4, the tool post 5 and the servo motor 34. It may be configured to be used as an NC lathe by connecting to an input / output terminal such as a personal computer and controlling the rotation angle of the main shaft 41 and the feed screw rod 33 and the position of the cutting tool 51 in the X-axis direction.

1 is an overall front view of a vertical lathe used in the present invention. 1 is an overall side view of a vertical lathe used in the present invention.

DESCRIPTION OF SYMBOLS 1 Vertical lathe 2 Base 3 Support part 30 Linear guide part 31 Hollow part 32 Bearing part 33 Feed screw rod 34 Servo motor 4 Spindle 40 Motor 41 Spindle 42 Chuck 5 Tool post 50 Arm 51 Bit 52 X-axis guide 6 Bathtub 7 Center Pedestal 70 tailstock 8 heater

Claims (4)

The base is provided with a longitudinally slidable main shaft and a bite that slides along the main shaft, and a chuck device that holds a bone fragment is attached to the lower end of the main shaft, and the upper surface is below the main shaft. An open bathtub is provided to fill the liquid, and the chuck device is configured to enter and exit the bathtub ,
After immersing bone fragments in the liquid in the bathtub and making the surface easy to cut,
A method for producing an osteosynthesis screw, wherein a bone fragment is taken out from the liquid in the bath and processed into a cylindrical shape, and then threaded . 2. The method for manufacturing an osteosynthesis screw according to claim 1, wherein the liquid is an aqueous solution selected from the group consisting of ethanol, acetic acid, sodium hydroxide, EDTA, and formaldehyde. The liquid is an aqueous solution of hyaluronic acid, and after the bone pieces are immersed in the aqueous solution of hyaluronic acid in the bathtub, they are taken out of the bathtub and cooled, and the surface of the bone pieces is frozen to make it easy to cut. 2. The method for producing an osteosynthesis screw according to claim 1, which is sequentially performed. The base is provided with a longitudinally slidable main shaft and a bite that slides along the main shaft, and a chuck device that holds a bone fragment is attached to the lower end of the main shaft, and the upper surface is below the main shaft. An open bathtub is provided to fill the liquid, and the chuck device is configured to enter and exit the bathtub,
The liquid is an aqueous solution of any one of the group consisting of ethanol, acetic acid, sodium hydroxide, EDTA or formaldehyde;
After immersing bone fragments in the aqueous solution to make the surface easy to cut, the bone fragments are removed from the bathtub and washed after columnar processing, and the liquid in the bathtub is replaced with physiological saline or hyaluronic acid aqueous solution.
A method for producing an osteosynthesis screw, wherein the washed bone fragment is immersed in the bathtub and threaded.

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