JP7406744B1 - Titanium spinal cage used for posterior interbody fusion surgery - Google Patents

Abstract

An object of the present invention is to provide a spinal cage that exhibits sufficient bone formation ability within an intervertebral disc space into which the spinal cage is inserted. [Solution] A plurality of openings communicating with the hollow core are formed on the upper and lower surfaces and left and right sides of a spinal cage body that is approximately bullet-shaped and has a hollow core, and a cage insertion device is provided at the rear end of the spinal cage body. A through-hole leading to the hollow core part that can be used for connection with the spine is provided, and when the spinal cage is inserted between the vertebral bodies of the patient's spine, the through-hole at the rear end of the spinal cage body can be used as a fluid inlet. A paste-like bone filling material is injected into the hollow interior of the core portion using the method. The paste-like bone filling material filled in the core part is pushed out of the core part using multiple openings formed on the upper and lower surfaces and left and right sides of the spinal cage body as fluid outlets, and is diffused into the intervertebral disc space of the spine. . [Selection diagram] Figure 4

Description

The present invention relates to a titanium spinal cage for use in posterior interbody fusion (TLIF/PLIF).

As society continues to age, the number of patients with age-related spinal diseases is increasing. A cage-shaped device called a spinal cage is used to treat spinal diseases such as intervertebral disc herniation, spinal canal stenosis, and vertebral compression fractures. The spine cage is a cage in which an instrument containing bone replacement materials such as autologous bone and calcium phosphate is inserted between the vertebrae to promote bone regeneration and fusion while maintaining the height between the vertebrae. The intervertebral discs located above and below the can be fixed.

Fig. 6 shows a conventional titanium spinal cage (Patent Document 1: Fig. 1 of Japanese Unexamined Patent Application Publication No. 2018-183571), and Fig. 7 shows a state in which the spinal cage is inserted into an intervertebral disc space between vertebrae. .
Referring to FIG. 6, unevenness 102 is formed on the upper surface of the main body 10 and the cage. The interior 140 of the cage is hollow and can contain bone replacement material. The titanium used in the spinal cage has excellent biocompatibility and has the property of bonding directly and firmly to bone.

After the doctor removes the intervertebral discs in the patient's spine, if the doctor inserts a spinal cage as a spacer between the vertebrae using a cage insertion device (see Figure 7), the patient's body fluids may enter the cage. , the bone-replenishing material such as calcium phosphate housed in the cage is apatitized/bone-replaced by a hydration reaction, and bone is formed in the intervertebral disc space.

JP2018-183571 Publication Publication

A spinal cage is inserted as a spacer between the vertebrae of a patient's spine and has the function of forming bone in the intervertebral disc space, which is a closed space surrounded by ligaments. In order to achieve this, it is necessary that the bone substitute material be supplied throughout the space of the intervertebral disc space. However, in conventional cages, a cage with bone-replacement material inside is inserted between vertebrae, so the bone-replacement material housed inside the hollow cage does not spread throughout the intervertebral disc space. Have difficulty. As a result, conventional spinal cages functioned as spacers between vertebrae and did not have a sufficient effect on bone formation within the intervertebral disc space using bone substitute materials.
Under the above circumstances, there is a need for a new spinal cage that can be inserted as a spacer between the vertebral bodies of a patient's spine to maintain the intervertebral height while forming sufficient bone within the disc space. It was getting worse.

In order to solve the above problems, the inventors of the present invention made extensive studies and found that after inserting a spinal cage between the vertebrae, a paste-like bone filling material is injected into the hollow inside the cage, and the injected paste is applied to the cage body. The inventors have come up with the idea that by extruding the bone grafting material to the outside through a plurality of openings provided on the sides of the cage, the bone grafting material can be diffused outside the cage and distributed inside the disc space. As a means of injecting the paste into the hollow interior of the cage, it was conceived that the through hole used for attaching the cage insertion device to the cage can be used as a fluid inlet.

Based on the above idea, the inventors of the present invention have developed a titanium spinal cage for use in posterior interbody fusion surgery, which includes:

The spinal cage is approximately bullet-shaped with a hollow core portion, and the hollow core portion is surrounded by a front end, an upper surface, a lower surface, a left side, a right side, and a rear end of the spinal cage main body. Ori,

The front end of the spinal cage main body is formed into a protrusion shape with a rounded tip,

One or more openings communicating with the hollow of the core are formed in the front end, upper surface, lower surface, left side surface, and right side surface of the spinal cage body, respectively,

A through hole communicating with the hollow of the core portion is provided at the rear end of the spinal cage body, and the spinal cage can be inserted into the hole by inserting the tip of the shaft of the cage insertion instrument into the hole. configured to be connectable to the cage insertion device,

With the spinal cage inserted between the vertebrae of the patient's spine, a paste-like bone replacement material is introduced into the hollow interior of the core using the through hole at the rear end of the spinal cage body as a fluid inlet. When injected and filled, the paste-like bone filling material filled in the core part flows through the core through a plurality of openings formed in the upper surface, lower surface, left side surface, and right side surface of the spinal cage main body. pushed out of the spinal column and diffused into the disc space of the vertebrae;

We have arrived at the invention of the titanium spinal cage.

The inventors of the present invention further provide a method for forming bone within the disc space of the spine using a titanium spinal cage used in posterior interbody fusion, comprising:

The spinal cage is approximately bullet-shaped with a hollow core portion, and the hollow core portion is surrounded by the front end, upper and lower surfaces, left and right side surfaces, and rear end of the spinal cage main body. The front end portion of the spinal cage body is formed into a protrusion shape with a rounded tip, and one or more openings communicating with the hollow core portion are formed on the upper and lower surfaces and left and right side surfaces of the spinal cage body, respectively. A through hole communicating with the hollow of the core portion is provided at the rear end of the spinal cage main body, and the spinal cage is attached to a cage insertion instrument using the through hole, and the spinal cage is inserted into the protrusion shape. It is configured so that it can be inserted between the vertebrae of the spine from the front end of the

inserting the spinal cage as a spacer between vertebrae of the patient's spine;

Injecting a paste-like bone filling material into the hollow interior of the core part using the through hole in the rear end of the spinal cage as a fluid inlet;

After the pasty bone filling material is filled into the hollow interior of the core portion, by continuing to inject the pasty bone filling material, a plurality of openings are formed on the upper and lower surfaces and the left and right sides of the spinal cage main body. pushing the paste-like bone grafting material out of the core part using the part as a fluid outlet and spreading it into the intervertebral disc space of the spine;

The inventors have arrived at the invention of a method for forming bone within the intervertebral disc space of the spine using the titanium spinal cage.

Preferably, all or some of the plurality of openings formed in the left and right side portions of the spinal cage main body have inner circumferential walls formed at an oblique angle with respect to the width direction of the spinal cage main body. ing. By adjusting the angle of the inner peripheral wall of the opening, it is possible to adjust the direction in which the paste-like bone filling material filled in the core portion of the spinal cage is pushed out of the cage.

Preferably, all or some of the plurality of openings formed in the left and right side portions of the spinal cage main body are formed such that the inner circumferential walls of the openings are formed at an oblique angle with respect to the width direction of the spinal cage main body. As a result, the position where the opening opens toward the outside of the spinal cage main body is larger in the longitudinal direction of the spinal cage than the position where the opening opens toward the core part. It is formed so as to be located at a position close to the front end portion.

Preferably, two or more openings are provided on each of the left and right sides of the spinal cage. It is desirable that a large number of openings be formed so that the paste-like bone filling material injected into the hollow interior of the spinal cage can be diffused into the intervertebral disc space through the openings. However, a large number of openings is disadvantageous for the strength of the cage. Additionally, a large number of openings increases the manufacturing cost of the spinal cage. Therefore, when designing a product, the openings are set to an appropriate number and size while taking these conflicting demands into consideration.

Preferably, the pasty bone replacement material includes autologous bone and calcium phosphate bone paste.

Preferably, the upper surface of the spinal cage is formed with an uneven shape, and the uneven shape of the upper surface prevents the spinal cage from moving back in a direction opposite to the insertion direction after the spinal cage is inserted between the vertebral bodies. Ru.

Preferably, the upper surface of the spinal cage is formed flat, and one or more stops are provided on the flat upper and lower surfaces. Since the upper surface of the spinal cage is formed flat, the contact area between the titanium surface and the bone is increased, and the bonding between the two is promoted. If the upper surface of the spinal cage is flat, the spinal cage is likely to move back in the direction opposite to the insertion direction after being inserted between the vertebral bodies, but this risk is prevented by the stopper.

Preferably, the spinal cage of the present invention is inserted between the vertebrae of a patient's spine using a cage insertion instrument. Although the spinal cage of the present invention can be inserted between vertebrae without using a cage insertion device, a doctor can insert the spinal cage between the vertebrae of a patient's spine by using a cage insertion device. It can be inserted and fixed easily and safely.

Preferably, a female screw for connecting and fixing the spinal cage to the tip of the shaft of the cage insertion instrument is preferably formed inside the through hole of the rear end.

Preferably, recesses are formed in the left and right corners of the rear end of the spinal cage, and a cage insertion instrument for inserting the cage between the vertebrae of the spine is inserted into the two left and right recesses. You can hold it by hand.

Preferably, after inserting the spinal cage between the vertebral bodies using a cage insertion instrument, the shaft of the cage insertion instrument is removed from the through hole at the rear end of the cage with the spinal cage remaining between the vertebral bodies, and then, The injection tube of the paste injection device is inserted into the through-hole, and the paste-like bone filling material is injected into the hollow interior of the spinal cage using the through-hole at the rear end of the cage as a fluid inlet.

Preferably, the cage insertion device is equipped with a syringe and an injection tube for filling the pasty bone grafting material, and the cage insertion device is attached by inserting the injection tube of the cage insertion device into a through hole at the rear end of the spinal cage. After inserting the spinal cage between the vertebral bodies using an instrument, in that state, pass the injection tube of the cage insertion instrument into the hollow interior of the spinal cage using the through hole at the rear end of the cage as a fluid inlet. inject.

Preferably, the body of the spinal cage comprises 64 titanium alloy (Ti-6Al-4V).

Preferably, the upper and lower surfaces of the spinal cage are textured to allow fusion between the titanium surfaces and the vertebrae.

The size of the spinal cage of the present invention is not particularly limited as long as it can be inserted and fixed between the vertebral bodies of a patient's spine. Assuming the spine of a Japanese adult with a standard physique, the size of the spine cage is preferably about 21 to 26 mm in the longitudinal direction, about 20 mm in the width direction, and about 6 to 14 mm in height.

In one embodiment of the spinal cage of the present invention, the bone replacement material is injected into the disc space through the spinal cage by injecting the pasty bone replacement material into the spinal cage after the spinal cage is inserted into the spinal canal. Therefore, a sufficient amount of bone-replenishing material can be supplied into the intervertebral disc space to achieve bone formation (heterotopic ossification) in the affected area of the intervertebral disc space.

In one embodiment of the spinal cage of the present invention, the spinal cage is provided with a large number of openings, so that the paste-like bone substitute material injected into the hollow core of the spinal cage passes through the large number of openings into the intervertebral disc space. It can be diffused widely and uniformly within the interior.

In one embodiment of the spinal cage of the present invention, a paste-like bone replacement material can be injected into the spinal cage using a through hole at the rear end of the spinal cage used for attaching the spinal cage to a cage insertion instrument as a fluid inlet. Therefore, there is no need to provide special equipment for injecting paste-like bone filling material into the cage.

In one embodiment of the spinal cage of the present invention, the upper surface of the spinal cage is formed flat, and a stopper is provided on the flat upper surface to prevent the spinal cage from falling out due to backward movement. By joining the flat titanium surface of the spinal cage and the vertebrae over a wide area, the spinal cage can be firmly connected to the vertebrae. The structure of the stopper is not limited to a particular structure as long as it can prevent the spinal cage from falling out due to backward movement, but in the embodiment shown in FIG. 2 of the present invention, a catch like the barb of a fishhook is provided.

In one embodiment of the spinal cage of the present invention, the bone replacement material contained within the spinal cage inserted between the vertebral bodies can be diffused throughout the disc space through the plurality of openings in the spinal cage, so that Sufficient bone formation can be obtained throughout the cavity.

One embodiment of the spinal cage of the present invention has a flat overall shape compared to conventional spinal cages, can be stably installed and fixed in the inserted position, and can withstand loads applied to the cage from various angles. be able to.

FIG. 1 shows a perspective view of one embodiment of the spinal cage of the present invention. FIG. 2(A) shows a top view of one embodiment of the spinal cage of the present invention. FIG. 2(B) shows a bottom view of one embodiment of the spinal cage of the present invention. FIG. 3(A) shows a left side view of one embodiment of the spinal cage of the present invention. FIG. 3(B) shows a right side view of one embodiment of the spinal cage of the present invention. FIG. 4(A) shows a method of injecting a paste-like bone filling material using the through hole at the rear end of one embodiment of the spinal cage of the present invention as a fluid inlet. FIG. 4(B) shows the direction in which the paste-like bone filling material injected into the through hole at the rear end of one embodiment of the spinal cage of the present invention is pushed out from the hollow interior of the spinal cage to the outside. FIG. 5(A) shows a cage insertion instrument used in one embodiment of the spinal cage of the present invention. FIG. 5(B) shows a cage insertion instrument used in one embodiment of the spinal cage of the present invention. FIG. 6 shows an example of a prior art spinal cage. FIG. 7 shows the spinal cage inserted into the intervertebral disc space between the vertebrae. FIG. 8 shows a flowchart of a method of forming bone in a disc space between vertebrae using the spinal cage of the present invention.

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 shows a perspective view of a spinal cage according to one embodiment of the present invention, FIG. 2(A) shows a top view of a spinal cage according to one embodiment of the present invention, and FIG. 2(B) FIG. 2 shows a bottom view of a spinal cage according to one embodiment of the invention. FIG. 3(A) shows a left side view of a spinal cage according to one embodiment of the present invention, and FIG. 3(B) shows a right side view of a spinal cage according to one embodiment of the present invention.

Referring to FIG. 1, the spinal cage of the present invention has a generally cannonball shape, the cage body 10 has a hollow core part 100, the hollow core part 100 has a rear end part 11 of the cage body 10, It is surrounded by a protruding front end portion 12, a left side surface portion 13, and a right side surface portion 14.

A through hole 101 is formed in the rear end portion 11 of the cage body 10. An opening 201 is provided on the upper surface 15 of the cage body 10, and an opening 301 is provided on the lower surface 16. Openings 401 and 402 are provided on the left side 13 of the cage body 10, and openings 501 and 502 are provided on the right side 14.

Referring to FIGS. 2(A) and 3(B) and FIGS. 3(A) and 3(B), the upper surface 15 and lower surface 16 of the cage body 10 are both formed flat. In order to prevent the cage from slipping out from between the vertebral bodies after the spinal cage is inserted between the vertebrae, it is preferable that the upper and/or lower surfaces of the cage be formed to be uneven rather than flat. However, if the cage is uneven, the contact between the upper and/or lower surfaces of the cage and the vertebrae becomes point contact, which reduces the contact area, which is disadvantageous for the connection between the titanium surface of the cage and the vertebrae. Therefore, in one embodiment of the present invention, the upper and/or lower surfaces of the cage body 10 are formed flat, and a stopper 21 is provided on the upper surface 15 of the cage body 10, and stoppers 31, 32, 33, and 34 are provided on the lower surface 16. ing. By making the upper surface 15 and the lower surface 16 of the cage body 10 flat, the contact area between the titanium surface of the cage and the vertebrae is increased, and the spinal cage and the vertebrae can be firmly connected. After inserting the spinal cage from its anterior end between the vertebrae of the patient's spine, the presence of the stopper prevents the inserted spinal cage from moving back and slipping out of the intervertebral space. can.

1 and FIGS. 5(A) and 5(B), by inserting the distal end of the shaft of the cage insertion instrument 1000 into the through hole 101 provided in the rear end 11 of the cage body 10, Connect the spinal cage to cage insertion instrument 1000. When the distal end of the shaft of the cage insertion instrument 1000 is bifurcated (Fig. 5(A)), two recesses 1001 and 1002 formed at both corners of the rear end 11 of the cage body 10 (Fig. The cage main body 10 can be attached to the distal end of the shaft of the cage insertion instrument 1000 by fitting the bifurcated distal end into the cage (see 3(A) and (B)).

Referring to FIGS. 4(A) and 4(B), the cage body 10 has a through hole 101 formed in the rear end portion 11 as a fluid inlet, and a paste-like bone grafting material is applied to the cage body in the direction indicated by the arrow. It can be injected into ten hollow cores 100. Referring to FIG. 4(B), the paste-like bone grafting material filled in the hollow core portion 100 of the cage body 10 is inserted into the opening 201 formed in the upper surface 15 and the opening formed in the lower surface 16. section 301, openings 401 and 402 formed on the left side surface 13, and openings 501 and 502 formed on the right side surface 14 as fluid outlets, respectively, to the outside of the cage body 10 in the direction indicated by the arrow. It is pushed out and spread into the disc space.

In the example shown in FIG. 4(B), the openings formed on the left and right sides of the spinal cage 10 are formed such that the inner peripheral wall of the opening is angled obliquely from the rear end toward the front end. . By forming the inner circumferential wall of the opening at an oblique angle with respect to the vertical cross section of the spinal cage 10, the direction in which the paste-like bone filling material filled in the core part 100 is extruded to the outside is controlled, and The paste-like bone grafting material filled in the core portion is smoothly pushed out of the spinal cage through the opening in the advancing direction.

1 to 4, the cage body 10 has one opening each on the top and bottom, and two openings on both left and right sides, but when designing the actual product, it is important to The number and size are appropriately determined depending on the spine of the target patient and the condition of the affected area.

FIG. 8 shows a flowchart of one method for inserting the spinal cage of the present invention between the vertebral bodies to diffuse pasty bone grafting material into the intervertebral space.

Although the embodiments of the present invention have been described above with reference to the drawings, the present invention is not limited to these embodiments, and can be implemented by changing to various embodiments within the scope of the present invention. is possible.

Explanation of the sign

10 spine cage body, 11 rear end of spine cage, 12 front end of spine cage, 13 left side of spine cage, 14 right side of spine cage, 15 upper surface of spine cage, 16 lower surface of spine cage, 21 stopper, 31 to 34 stopper, 201 spine Cage top opening, 301 Spine cage bottom opening, 401 Spine cage left side opening, 402 Spine cage left side opening, 501 Spine cage right side opening, 502 Spine cage right side opening, 1000 Cage insertion instrument

Claims (5)

A titanium spinal cage used for posterior interbody fusion,

The spinal cage is approximately bullet-shaped with a hollow core portion, and the hollow core portion is surrounded by a front end, an upper surface, a lower surface, a left side, a right side, and a rear end of the spinal cage main body. Ori,

The front end of the spinal cage main body is formed into a protrusion shape with a rounded tip,

One or more openings communicating with the hollow of the core are formed in the upper surface, lower surface, left side surface, and right side surface of the spinal cage body, respectively,

A through hole communicating with the hollow of the core portion is provided at the rear end of the spinal cage body, and the spinal cage can be inserted into the hole by inserting the tip of the shaft of the cage insertion instrument into the hole. configured to be connectable to the cage insertion device,

With the spinal cage inserted between the vertebrae of the patient's spine, a paste-like bone replacement material is introduced into the hollow interior of the core using the through hole at the rear end of the spinal cage body as a fluid inlet. When injected and filled, the paste-like bone filling material filled in the core part flows through the core through a plurality of openings formed in the upper surface, lower surface, left side surface, and right side surface of the spinal cage main body. pushed out of the spinal column and diffused into the disc space of the vertebrae;

The upper and lower surfaces of the spinal cage are formed flat, and the flat upper and lower surfaces are surface-treated so that the titanium surfaces and the vertebrae fuse together, and the flat upper and lower surfaces each have one or more A plurality of stoppers are provided, and the stoppers are configured to prevent the spinal cage from moving back in a direction opposite to the insertion direction after the spinal cage is inserted between the vertebral bodies,

All or part of the plurality of openings formed in the left and right side parts of the spinal cage main body,
A position where the spine cage body is opened toward the core portion thereof is located closer to the rear end portion in the longitudinal direction of the spine cage body than a position where the spine cage body is opened toward the outside of the cage body. It is formed as follows, and
The spinal cage main body is formed such that a position opening toward the outside is located closer to the front end portion in the longitudinal direction of the spinal cage than a position opening toward the core portion. ing,

The titanium spine cage.
The titanium spinal cage of claim 1, wherein the pasty bone replacement material comprises autologous bone and calcium phosphate bone paste.
The titanium spine cage according to claim 1 or 2, wherein the spine cage body comprises 64 titanium alloy (Ti-6Al-4V).
The titanium spinal cage according to claim 1 or 2, wherein a female screw is formed inside the through hole of the rear end portion for connecting and fixing the spinal cage to the tip of the shaft of the cage insertion instrument.
Recesses are formed in the left and right corners of the rear end of the spinal cage, and a cage insertion instrument for inserting the cage between the vertebrae of the spine is grasped using the two left and right recesses. The titanium spinal cage according to claim 1 or 2, wherein the titanium spinal cage can be

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