WO2010008353A1

WO2010008353A1 - Less invasive intervertebral fusion cage

Info

Publication number: WO2010008353A1
Application number: PCT/TR2008/000080
Authority: WO
Inventors: Ugur Tabuktekin
Original assignee: Hays Saglik Urunleri Ic Ve Dis Ticaret Limited Sirketi
Priority date: 2008-07-15
Filing date: 2008-07-15
Publication date: 2010-01-21
Also published as: TR201100050T2

Abstract

The invention relates to a less invasive cage (K) for use in the thoracal and lumbar regions in the spinal column surgery, said cage being applied unilaterally to stabilize a vertebra (V) with respect to another vertebra (V) in the spinal column, and being opened inside the body after placing the implant between the vertebrae (V) by means of a small incision and the removal of a small amount of bone, said invention comprising at least one first slice (2), at least one intermediate slice (3) connected with said first slice (2) and between themselves by way of joint, at least one last slice (1) connected to be jointed with said intermediate slice (3) and to contact said first slice (2), to enable said cage (K), in open or closed state and with a form with radius and/or with an angled form, to assume its final shape in the zone of application.

Description

LESS INVASIVE INTERVERTEBRAL FUSION CAGE

Technical Field

The invention is used in the thoracal and lumbar regions in the spinal surgery. It is the field of interest for the experts of both neurosurgery and the orthopedics. Spinal column is a fairly complex structure, which protects and preserves the critical elements in our nervous system and which, despite its complex nature, has a flexible structure capable of high degrees of angle formation and rotation. The below listed spinal disorders may cause the limitation in the capability of movement and may lead the critical nervous system elements being protected to be threatened:

• Mechanical instabilities caused by genetic or developmental disc degeneration

• Spinal stenosis

• Spondylolisthesis

• Fractures • Tumors

• Scoliosis

The invention relates in particular to a less invasive cage, which is employed unilaterally to stabilize one vertebra with respect to another vertebra in the spinal column, as one of the surgical therapy options of such disorders, and which is opened inside the body after the placement of the implant between the vertebrae by means of a small incision and a small amount of bone removal.

State of the Art Today, there exist different structures and the applications for these structures in order to eliminate the aforesaid disorders in the art. Basically, all the structures and applications involve similar surgical techniques. Incision made unilaterally and the removal of a part of the lamina and facet bones on the entrance path are repeated for the other side. Cage locations are prepared and are left in position by means of the senders.

The basic objective in the surgical operation is to achieve the therapy by intervening in such a way to deform the natural structure to the least possible extent. As seen in Figure 6, in said cages used by way of placement one piece on each side, that is in a bilateral manner, a higher extent of intervention with the anatomic structure, a larger incision and the removal of a higher amount of bone are involved.

Also present in the state of the art is the Xycor PLIF cage, which has not yet been presented to use, but has been introduced at the international meetings. The differences of this product from the other PLIF cages are that it is applied unilaterally and that the implant is opened inside after being placed between the vertebrae by means of a smaller incision and a less amount of bone removal.

Also today, in the patent document no. US 2007/0288018 titled "Expandable spinal implant", the invention of XYCOR PLIF cage mentioned in the previous paragraph relates to an expandable spinal implant comprising a first member and a second member. Said first and second member are axially joined to one another between the closed position and the expanded position, in order to provide structural support for the spinal column, with the aim of placing an implant into the spinal column to perform dependent movement on the rotational axis. Said expanded implant comprises a lock mechanism to restrict the relative movement between said first and second members.

Again today, in the patent document no. EP1897518 titled "Spinal implant end instrument", the invention relates to the spinal implant and an instrument kit used to fit an implant inside a disc cavity in order to prepare said disc cavity.

Also today, in the patent document no. EP1354572 titled "Implant and material for minimally invasive interbody fusion surgery", the invention relates to a spinal in-body fusion implant device, which has an oval form when viewed from the top and a double convex form when viewed transversely, said device having a structure similar to a scraped human disc cavity and comprising a first modular terminal part, a residual modular middle section adjacent to at least said first modular terminal part, a residual second modular terminal part adjacent to said modular middle section, and a middle section and a middle terminal section positioned adjacent to one another. Further, in the patent document no. US 2005/0027360 dated "Spinal implant", the invention relates to a spinal implant that can be used in stabilizing a piece of vertebra. Said implant may be used to increase the growth of the bone between the adjacent vertebrae, for the purpose of enabling the fusion of the vertebra. Implant may include an implant along the height of the implant body and oval edges.

Further, in the patent document no. EP 1430858 titled "A pair of lumbar interbody implants and method of fusing together adjoining vertebrae bodies", the invention relates to a pair of lumbar interbody implants designed to perform lateral pushing to enable the displacement of the disc in the space between the adjacent vertebrae. Each implant comprises a first and second saggital wall and a terminal front wall and a subsequent wall. These two implants are asymmetric with respect to each other and are suitable for the trans-foraminal lumbar interbody fusion. A first implant preferably comprises an inclined outer surface and a first saggital wall and second saggital wall in essentially plane form.

As a result, the presence of the need for a less invasive cage and the inadequacy of the existing solutions have made it necessary to provide an improvement in the relevant art.

Object of the Invention

In order to eliminate the disadvantages of the state of the art, an object of the invention is to provide the second PLIF cage applied in a unilateral manner in the world market

Another object of the invention is to enable the surgical operation with a smaller incision and less bone removal as compared to the PLIF cage surgeries of the prior art.

Another object of the invention is to shorten the operation time owing to less surgery, and consequently to reduce the costs for surgeon and operating room, etc. Another object of the invention is to provide that the patient has less surgical incision and less pain and higher living comfort as compared to the other uses of PLIF cage owing to the less damage to the natural structure, that the patient is able to recover faster, that the patient is able to return its daily life earlier, that the patient is discharged from the hospital earlier and thus the extra accommodation cost is reduced and that vacancy for a new patient is provided earlier owing to the less use of the hospital facilities.

Another object of the invention is to enable easy adaptation with the other intervertebral fusion techniques owing to the basic operating principle, and thus to maximize the level of the minimal invasive surgery.

Another object of the invention is to enable the product to become more demanded with the extending indications owing to the operating principle's being favorable for development.

Still another object of the invention is to provide an equal load distribution on the implant owing to the circular structure, thereby keeping the extent of subsidence to a minimum in the zone of implant application.

Still another object of the invention is to provide a tight grasp to the lower and upper vertebra in the zone of application owing to the pins it bears and thus to avoid the risk of dislocation and migration mostly observed in the cages.

Still another object of the invention is to provide a faster fusion formation due to the perforated structure and the wide grafting zone.

According to a preferred embodiment of the invention, the object is to enable the system's closing trigger to be carried out by means of another part or mechanism, rather than the resilient member.

According to another preferred embodiment of the invention, it is possible to perform the application by way of slicing in a geometric shape other than the circular shape. The structural and characteristic features and all the advantages of the invention will be more clearly understood from the figures provided below and the detailed description written with reference to said figures, hence the evaluation must be made taking into consideration these figures and detailed description.

Description of the Figures

Figure 1a is the side view of the application site of the invention.

Figure 1b is the top view of the application site of the invention.

Figure 2, 3 are the perspective views of the assembly application of the invention.

Figure 4 is the assembly perspective view of the invention.

Figure 5 is the disassembly perspective view of the invention.

Figure 6 is the view of the bilateral cage structure according to the prior art.

Detailed Description of the Invention

In Figure 1a, the representative view of the zone where the application is to be made is provided. The object of the invention is to provide the cage (K) with its final shape at the inside so that it may be located at the relevant point with minimum section, instead of the anatomic damages and interventions resulting from the requirement for a big section to deliver the same during the application. In the fusion surgery between the vertebrae (V) (intervertebral), the surgical intervention is carried out between the adjacent vertebrae (V), and a cage (spacer) (K) is placed in between, in order to provide the formation of the fusion by preserving the distance between the two vertebrae (V) (Figure 1b). This type of therapy is called the fusion surgery. A successful fusion means the stabilization of this zone.

In Figures 2 and 3, the perspective view is provided of the assembly application of the invention. According to the figure, the design is made based on the logic that the ring-shaped cage (K) having the suitable wall thickness will be divided into slices (1 , 2, 3), said slices (1, 2, 3) will be joined with the pins (4) serving the function of hinge, and the resilient member (5) will forcibly close to reassume the ring shape. Said cage (K) structure comprises a first slice (2), more than one intermediate slice (3) jointed to the first slice (2), and a last slice (1) jointed to the intermediate slices (3) and contacting said first slice (2) to close and thus to provide the formation of a round cage. Since said slices (1 , 2, 3) are jointed to each other, they also have the capability of making angles towards the right-left with respect to each other.

Figure 5 provides the disassembled perspective view of the invention. According to the figure, there is seen an intermediate slice (3) comprising an upper surface (3.5), a lateral surface (3.3) for the positioning of the resilient member (5) that will provide the joint with another slice, i.e. the intermediate slice (3), resilient member lower and upper positioning spaces (3.6, 3.7) and a seating surface (3.4), the pin spaces (3.1) through which the pin (4) passes to enable the fixing of the resilient member (5), an upper surface (3.5) and a control space (3.2) for the purpose of control.

Also in Figure 5, there is seen a first slice (2) comprising an upper surface (2.5), a lateral surface (2.3) for the positioning of the resilient member (5) that will provide the joint with another slice, i.e. the intermediate slice (3), resilient member lower positioning space (2.8) and a seating surface (2.4), the pin spaces (2.1) through which the pin (4) passes to enable the fixing of the resilient member (5), an upper surface (2.5) and a control space (2.2) for the purpose of control. In addition, there are formed a recess (2.6) and a recess lateral surface (2.7) next to the first slice (2), contacted by the first slice (2) upon the joint of the same with the last slice (1).

Also in Figure 5, there is seen in a last slice (1) comprising an upper surface (1.5), a protrusion (1.3) and a protrusion lateral surface (1.4) formed next to the first slice (2), contacted upon the joint with a first slice (2), the pin spaces (1.1) through which the pin (4) passes to enable the fixing of the resilient member (5) that will provide the joint with an intermediate slice (3) and a control space (1.2) for the purpose of control.

Said pin (4) is located in a perpendicular alignment inside the pin spaces (1.1 , 2.1 , 3.1) and it comprises two pointed ends (4.1). Said ends (4.1) enable said cage (K) to be seated by way of being fixed to the vertebrae (V).

Said resilient member (5) has two ends (5.1 , 5.2), namely the upper and the lower end, respectively. Said upper end (5.1) is located in the resilient member upper positioning space (3.7), while the lower end (3.6) is located in the resilient member lower positioning space (3.7).

Our invention is maintained in the ring form, i.e. in free form, prior to application (Figure 8). Following the completion of the preparatory processes required between the two vertebrae (V), the size of the cage (K) to be used is determined. Once the cage (K) to be employed is determined, the following process steps are performed: - The cage (K) is opened and placed in the sender such that it will form a single line.

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- It is placed in the application zone along with the sender.

- With the cage (K) in open state, it is started to be pushed forwards by the sender in a controlled manner (Figure 2).

- First slice (2) exits through the mouth of the sender and moves in the entrance direction of the sender until arriving at the last slice (1) between the two vertebrae (V).

- Upon the arrival at the end of the first slice (2), the resilient member (5) becomes active to enable the slice (2) to close.

- After the first slice (2), intermediate slices (3) also perform the same movements as the first slice (2) and they follow the same path. Upon the release of each slice (1 , 2, 3) from the sender, the resilient member (5) in between enables the slices (1 , 2, 3) to lean against each other and to close.

- These processes continue until the last slice (1). Location check is performed while the last slice (1) is inside. If the location is not proper, the cage (K) is retracted, and the application is repeated until the correct placement of the cage (K). Following the verification of the appropriateness, the last slice (1) is not pushed, the sender releases the last slice (1) and withdraws. The last slice (1), upon being released from the sender, performs the closing movement by means of the adjacent resilient member (5) and contacts the first slice (2) to enable the system to close (Figure 3).

Preferably, the spring is used as the resilient member (5). Like said resilient member, it will be possible to use the different parts that will provide the cage structure (K) with the capability of flexing in order to provide a limited axial movement towards the right- left between the slices (1 , 2, 3).

Sender is a hand tool used in the application of the invention to the relevant zone. The invention is placed inside the sender as opened in the form of a single line (Figure 2). The tip of the hand tool, i.e. the sender, is brought to the proper zone for the placement of the invention, it releases the invention placed in opened state, in a controlled manner, by pushing the slices (1 , 2, 3) outwards one by one by means of its specially designed mechanism and enabling it to close and assume the shape of the exiting slices (Figure 3), and the placement of the invention in the zone is completed upon the release of the last slice (1) (Figure 4).

Said slices (1 , 2, 3) may be controlled by way of being moved with the help of the surgical apparatus (sender) through the control spaces (1.2, 2.2, 3.2) formed at the centers thereof.

The protective scope of this application is determined in the section of the claims, and the scope may by no means be limited to the description above provided only for exemplary purposes. It is obvious that a person skilled in the art may provide the innovation put forward by the invention also by using the similar embodiments and/or may apply this embodiment to the other fields used in the relevant art for similar purposes. Consequently, such embodiments would obviously lack the criterion of innovative step.

Claims

1. The invention relates to a less invasive cage (K) for use in the thoracal and lumbar regions in the spinal column surgery, said cage being applied unilaterally to stabilize a vertebra (V) with respect to another vertebra (V) in the spinal column, and being opened inside the body after placing the implant between the vertebrae (V) by means of a small incision and the removal of a small amount of bone, characterized in that it comprises at least one first slice (2), at least one intermediate slice (3) connected with said first slice (2) and between themselves by way of joint, at least one last slice (1) connected to be jointed with said intermediate slice (3) and to contact said first slice (2), to enable said cage (K), in open or closed state and with a form with radius and/or with an angled form, to assume its final shape in the zone of application.

2. A cage (K) according to Claim 1 characterized in that it comprises the resilient member (5), which enables the slices (1, 2, 3) to be jointed to one another such that they can perform a limited axial movement towards the right-left and thus, provides said cage structure (K) the capability of flexing.

3. A cage (K) according to any one of the preceding claims characterized in that it comprises an intermediate slice (3) comprising an upper surface (3.5), a lateral surface (3.3) for the positioning of the resilient member (5) that will provide the joint with another slice, i.e. the intermediate slice (3), resilient member lower and upper positioning spaces (3.6, 3.7) and a seating surface (3.4), the pin spaces (3.1) through which the pin (4) passes to enable the fixing of the resilient member (5), an upper surface (3.5) and a control space (3.2) for the purpose of control.

4. A cage (K) according to any one of the preceding claims characterized in that it comprises a first slice (2) comprising an upper surface (2.5), a lateral surface (2.3) for the positioning of the resilient member (5) that will provide the joint with another slice, i.e. the intermediate slice (3), resilient member lower positioning space (2.8) and a seating surface (2.4), the pin spaces (2.1) through which the pin (4) passes to enable the fixing of the resilient member (5), an upper surface (2.5) and a control space (2.2) for the purpose of control.

5. A cage (K) according to any one of the preceding claims characterized in that there are formed a recess (2.6) and a recess lateral surface (2.7) next to said first slice (2), contacted by the first slice (2) upon the joint of the same with the last slice

(1).

6. A cage (K) according to any one of the preceding claims characterized in that it comprises a last slice (1) comprising an upper surface (1.5), a protrusion (1.3) and a protrusion lateral surface (1.4) formed next to the first slice (2), contacted upon the joint with a first slice (2), the pin spaces (1.1) through which the pin (4) passes to enable the fixing of the resilient member (5) that will provide the joint with an intermediate slice (3) and a control space (1.2) for the purpose of control.

7. A cage (K) according to any one of the preceding claims characterized in that it comprises the pin spaces (1.1 , 2.1 , 3.1) where said pin (4) is positioned in a perpendicular manner and at least one pointed end (4.1) to enable said cage (K) to be seated by way of being fixed to the vertebrae (V).

8. A cage (K) according to any one of the preceding claims characterized in that in said cage (K), there is present the capability of making angles towards the right-left between the previous and the next intermediate slices (3), between the first slice (2) and the intermediate slice with which it is jointed, between the last slice (1) and the intermediate slice (3) with which it is jointed.

9. A cage (K) according to any one of the preceding claims characterized in that said resilient member (5) is a spring.