WO2001003614A1

WO2001003614A1 - Intervertebral fusion cage

Info

Publication number: WO2001003614A1
Application number: PCT/FR2000/001961
Authority: WO
Inventors: Frédéric Fortin; Vincent Pointillart
Original assignee: Fortin Frederic; Vincent Pointillart
Priority date: 1999-07-13
Filing date: 2000-07-07
Publication date: 2001-01-18
Also published as: FR2796268A1; FR2796268B1; AU6295400A

Abstract

The invention concerns a device for maintaining (1)a bone structure, consisting of a container (2) capable of being cut and deformed, recovering its initial shape, and having an injection hole (21), said first means being combined with a brace (3) having two pins (31 and 34) enabling the container to be centred when set between two vertebrae. Said device (1) is perfectly suited in cases of bone removal resulting from metastasis; it enables, after it has been set in place, the injection of a retaining and filling product, while avoiding the risk of dangerous spreading inside the human body, and it also provides very good mechanical strength. The position of the device before injection is shown at Fig. 5. In another embodiment of the brace, the latter being deformable, is inserted in the container using a gripper so that it is securely anchored in the bones.

Description

INTERVERTEBRAL FUSION CAGE

Field of the Invention: The invention is a holding device which also makes it possible to contain a product of the cement type.

The assembly thus formed can replace, for example, one or more vertebrae which can no longer perform the maintenance function, in particular of the spine. PRIOR ART: Within the framework of the surgical operations carried out for example to treat vertebral metastases, the surgeon proceeds to the partial or complete ablation of the bone which can be a vertebra. No mechanical behavior nor maintenance are then ensured. In the prior art, these deficiencies were remedied by placing a simple rod between the vertebrae, then a cement was injected to fill the empty spaces left by the surgical ablations. This rod was introduced between two healthy bones (or vertebrae) to ensure a first shoring, then we proceeded to fill with a product to solidify the cement type appropriate for this type of operation. The absence of a container for the product led to an expansion with drawbacks:

Form of the injected product, once solidified, uncontrolled and does not guarantee the expected rigidity

Damage to the surrounding organs by the cement which, when it solidifies, gives off heat, on vital organs: such as, for example, the spinal cord which can lead to certain operations being prohibited.

Another technique used also consisted in replacing the rod and the cement by a rigid mesh structure called: Harms cage in which bone graft is introduced to fill as best as possible and obtain a bone support, but whose the installation is not easy and requires, distracting the adjacent vertebral bodies. This technique applies mainly in the case of patients who have healthy bones with trauma, but it does not apply in most cases of metastases where bone grafts are ineffective.

The present device which is the subject of the invention, on the other hand, is capable of solving the problems posed both in the case of healthy bones and of bones affected by metastases.

It will therefore essentially consist of a central retaining rod called prop having appropriate means, making it possible in particular to fulfill the following functions: ensuring good mechanical strength of the framework maintaining at the periphery a container which will receive the retaining product and filling which will thus be contained and cannot therefore spread in the human body during the injection.

DESCRIPTION

Figures 1, Ibis and 1 ter of the board 1/4 give three overall views of a first means of the invention called prop.

Figure 2 of plate 1/4 shows a type of container used, namely: a hollow and flexible cylinder provided with an injection hole.

Figure 3 of the board 1/4 shows the two previous means which combined form the holding device, the latter being taken in a clamp for placement by the surgeon

Figure 4 of plate 2/4 shows a method of positioning the device with its various means positioned between two half-vertebrae in section with a representation of the spinal cord

Figure 5 of Plate 2/4 shows on the same bone configuration the device in place ready for injection. Figure 6 of Plate 3/4 shows the device, once the filling product has been injected. Figures 7 and 8 of plate 4/4 show a container having injection holes, and an induction hole in said container of a deformable strut. Figures 9 and 9a show the establishment of a deformable strut using a specific clamp having a groove in at least one of its jaws (detail Figure 9a-cross section view)

The holding device 1 which is the subject of the invention comprises:

A preferably cylindrical container 2 intended to enclose a filling and holding product which will be injected into this cylinder through a hole 21 placed in the center of its lateral surface.

This container must be able to be made of a material such that it is easily cut to adapt to the dimensions of the cavity and sufficiently flexible to deform during its introduction and to adapt to the shape of the cavity while avoiding the product. to inject to spread into the human body. It can be manufactured in a deformable material having as essential function to regain its initial shape, it can be manufactured in a polymer, composite or metallic material provided that it is flexible enough to admit elastic deformations. The container, once manufactured, can be cut, with a pair of scissors by the surgeon who adapts it, as he wishes, to the height of the cavity.

A strut 3 which in a first embodiment is a rod preferably made of titanium or any other resistant and stainless material, and comprising at its ends two points 35 and 36 which will fix the strut by penetration into healthy bones . This strut has in the upper half of its length a perpendicular pin 31 fitted on a ring 32 sliding on the strut; said pin completely passing through the prop 3, its end being able to move in an oblong slot 33 made in the axis of the prop 3 which allows the assembly 31 and 32, a sort of variable bracket 37 made up of the means 31 and 32 of se move in translation down when setting up then up when was to find its position. In its lower part, the prop 3 also has a second fixed pin 34 which prevents the container 2 from decentring with respect to the prop, which would be very detrimental at the time of injection, the positioning and filling of the product. as well as its mechanical rigidity.

Figure 3 shows the grip of the device 1 with pliers; the variable pin 31 and the fixed pin 34 ensure correct centering of the container 2, during and after the installation of the device 1.

During the installation of the device 1 which is the subject of the invention (fig4), the surgeon grasps the device 1 with pliers, passing the latter through the hole 21 of the container 2; it presents the assembly at an angle along an oblique axis; it penetrates the two points of the prop 3 in the bones by a straightening movement which follows an arc of rotation so that the 2 points of the prop 3 can enter one after the other into the two bones. This operation is possible thanks to the momentary deformation of the container 2 during the positioning, as well as to the possible escape of the pin 31 thus avoiding abutting on the vertebral plate during the positioning of the stay. The surgeon will thus have inserted the device 1 into the cavity to be filled. This device is then ready for injection of the product chosen for the maintenance and filling (fig 5).

The injection is then carried out through the hole 21 of the container 2 using for example a syringe or any other suitable means. As a result of the characteristics of the injected product, said product is housed in the interstices existing between the bones and the device, without disturbing the surrounding organs; the whole "injected product combined with device 1", forms a solid and homogeneous block (fig 6) This device 1 can also be used to fill cavities between two bones, which are not necessarily vertebrae either come fill one or more cavities formed by the ablation, in particular of one or more metastases located inside the bone which the surgeon will have ablated and which it is absolutely necessary to stiffen. Of course, all the materials are compatible with long-term implantations in the human body, there are no major rejection problems on this side, since they are already used in other surgical applications. The strut can be easily bent to reproduce the anatomical curvature of the spine.

A variant of the prop 3 is proposed (fig 1 ter), the prop 3 in this case has two fixed perpendicular pins 31 bis and 34. This type of prop is used when the distance between the two bones is sufficient to allow an establishment similar to that already described; in this case it is a matter of inserting the device 1 between two bones far enough apart to not require the presence of the variable pin 31; the penetration of points 35 and 36 is effected by biasing the device 1, relatively easy to perform when the intervertebral distance is sufficient.

Another application of this invention consists in the possibility of passing the device 1 through a trocar thus making it possible to carry out interventions under endoscopy. The container can by the flexibility of the material which composes it be folded back on itself to enter the trocar. This intervention is performed on the thoracic vertebrae and thus avoids a heavy operation (large opening). The positioning of the strut 3 and the container 2 which make up the device 1 is also done by endoscopy, as it is now described: main variant with respect to the previous application, coming from the fact that the container is made of a material whose flexibility allows the latter to be folded up for its introduction by a trocar, the container 2 resuming its initial shape as soon as it found placed in the cavity. The product can be injected by passing it through pipes reaching the hole 21 of the container 2 at the end of which is the injection syringe.

In a second variant embodiment, the latter comprises a new deformable strut 4 which is placed in a container 2bis to be placed in the cavity to be filled; this positioning is carried out using a specific clamp 41 which first takes the strut 4 between its jaws thanks to a small groove 47 (detail in fig 9a) which prevents it from sliding, it is penetrate through a hole 21 bis located in the center of the container 2bis, then tighten the deformable strut 4 with the specific pliers 41 so that the points of the prop re-enter the bones for solid fixation, ensuring a good anchoring and thus strengthen the bone structure which we will then fill with cement by injecting the latter with two holes 45 and 44 preferably placed symmetrically with respect to the previous central hole 2 Ibis; we strongly press on the clamp so that the strut of the strut 4 which remains after tightening has a footprint as small as possible leaving only a slight protuberance outside the container (2bis) which will not disturb the medium. This alternative embodiment has the advantages of having an easy installation very good support of the frame, without disturbing the anatomical environment.

The various means described above allow a variety of applications, to which they can be adapted on a case by case basis.

Claims

R E V E N D I C A T I O N S

1 - Holding device (1) intended to be placed between bones which receives a holding and filling product, characterized in that it comprises the combination of two means: -a first means which is a container (2ou2bis)) of said deformable, cut, foldable product, returning to its original shape, and comprising a central hole (21 or 2 Ibis).

a second means which is presented in two embodiments: a strut (3) consisting of a rod made of rigid material, or a strut (4) made of deformable material, these two means allowing easy positioning and adapted to each cavity, resulting from a removal of the bone by ensuring a solid anchoring and by avoiding any spreading in the human body of the maintenance and filling product. 2-holding device (1) according to claim 1 characterized in that the container (2) consists of a flexible material of the polymer, composite or metallic type which admits elastic or plastic deformations during its insertion and which can resume its initial shape without exerting constraints on the support points, allowing easy installation of the device, and comprising at least one hole (21) for injecting the product. 3- holding device (1) according to any one of the preceding claims characterized in that its strut (3) has at least two pins perpendicular to its axis, at least one of which is fixed, which allows said container to be correctly centered (2) when it is placed between the bones.

4-Holding device (1) according to the preceding claims 1 and 3 characterized in that its strut (3) comprises fixing points (35) and (36) allowing the strut (3) to penetrate into the two bones thus ensuring a solid anchoring of the device (1) 5-Disposiϋf holding (1) according to one of the preceding claims characterized in that its strut (3) has a fixed pin (34) and a movable pin (31) which can move perpendicular to the axis of the forestay through an oblong slot (33). 6-holding device (l) according to one of the preceding claims characterized in that its container (2) is made of a material whose characteristics must be such that it can be cut, for example, with a simple pair of scissors, at the desired height so that it can be tailor-made to the cavity to be filled, and it is possible to fold it up so that it can be easily inserted into the housing provided.

7-holding device (l) according to claim 1 characterized in that it may include a deformable prop (4) placed in said container (2a) provided for this purpose, thanks to a specific clamp (41) which allows to present the strut (4) by a central hole (21bis) made in said container which then allows to tighten it to make the points of said strut penetrate into the bone.

8- holding device (1) according to claims 1 and 7 characterized in that the specific clamp (41) has a groove (47) adapted to the diameter of the strut on at least one of its jaws to allow the introduction of the deformable prop (4) without risking an escape or a sliding of the latter between the jaws of the clamp (41).

9-holding device according to claims 1 and 7 characterized in that its container (2bis) is suitable for the establishment of the deformable stay by the fact that it has a central hole (21a) and two holes ( 44) and (45) offset with respect to the central hole to allow injection of the product. 10-holding device (1) according to one of the preceding claims 1 and 7 characterized in that its deformable strut (4) once introduced into the container and clamped between the bones leaves appearing out of the container (2bis) only a weak protuberance which does not disturb

> not the surrounding environment