WO2004000177A1 - Device for the placement of a reversible intersomatic cage between vertebral bodies - Google Patents

Abstract

The invention relates to a placement device, comprising a tool (14) with a manipulating grip (19) fixed to a tube (20), assembly means (23, 24, 33) and a follower bar (21) guided and immobilised within the tube (20).

Description

 DEVICE FOR SETTING UP A REVERSIBLE INTERSOMATIC CAGE BETWEEN BODIES

VERTEBRAL

The present invention relates to a device for placing an interbody cage between the vertebral bodies of a spinal column. Also, the present invention relates to a follower rod allowing the location of the interbody cage during the surgical operation.

The device for setting up an intersomatic cage according to the present invention comprises a tool which consists of a grip handle secured to a tube and assembly means for fixing a follower rod inside. of the tube.

The positioning device according to the present invention comprises assembly means which consist of a rod guided inside the bore of the tube, of a wheel allowing the rod to be driven in rotation, and a hexagonal profile provided in the bore of said tube for locking in rotation the follower rod inside the tube.

The positioning device according to the present invention comprises a handle comprising a housing inside which rotates the knob in order to drive the rod inside the tube bore, said housing being closed above the wheel by a plate forming a striking zone on the tool.

The positioning device according to the present invention comprises a follower rod comprising a threaded part and opposite to the latter a hexagonal profile or the like extending by a threaded end.

The positioning device according to the present invention comprises a tube comprising opposite the handle of the lugs.

The positioning device according to the present invention comprises a tube comprising in its internal part a first bore which is extended by a second bore whose internal diameter is less than that of the first. The description which follows with reference to the appended drawings, given by way of nonlimiting examples, will allow a better understanding of the invention, the characteristics which it presents and the advantages which it is capable of providing: FIG. 1 is a view in perspective illustrating the interbody cage according to the present invention. Figure 2 is a view showing the vertebral bodies of the vertebrae above and below a vertebral column viewed from the front between which are introduced the intersomatic cages according to the present invention. Figure 3 is a view showing the vertebral bodies of the vertebrae above and below a vertebral column viewed in profile between which are introduced the intersomatic cages according to the present invention.

Figure 4 is a perspective view showing the device or instrumentation for the establishment of the interbody cage.

Figure 5 is a perspective view showing a follower rod allowing the mechanical connection between the interbody cage and the positioning device according to the present invention.

Figure 6 is a sectional view illustrating the operating head of the positioning device according to the present invention.

Figure 7 is a sectional view showing the attachment of the follower rod at the end of the positioning device according to the present invention.

Figures 8 and 9 are views showing the interbody cage mounted on the positioning device according to the present invention. An intersomatic cage 1 has been shown in FIG. 1 having a curved profile to affect, for example, the shape of a half banana.

The intersomatic cage 1 consists of a body 2 made of a translucent radio material, that is to say, it is not visible during radiological shots. The material used can be, for example, because of its technical and physical characteristics, a material sold under the name of PEEK.

The intersomatic cage 1 consists of a body 2 having in its middle a through space 3 intended to receive, for example, a bone graft not shown.

The body 2 has upper 4 and lower 5 edges, curved lateral faces 6, 7 joined together by a front face 8 with rounded profile and a flat rear face 9, the assembly delimiting the internal space 3.

The upper 4 and lower 5 edges respectively comprise on each side of the internal space 3 teeth 10 with an inclined profile which are directed towards the rear face 9 of the body 2 of the cage 1.

The profile of the teeth 10 is provided to constitute a retaining element of the interbody cage 1 between the vertebral bodies of the above and underlying vertebrae VS, VI of a vertebral column. The lateral face 6 forming the internal face with the radius of curvature of the body 2 in the form of a half banana is pierced with two holes 11 and 12 opening out inside the internal space 3. In fact, the other lateral face 7 constitutes the external face to the radius of curvature of the body 2 in the form of a half banana.

The rear face 9 is pierced with a threaded bore 13 which is intended to cooperate with a tool 14 for the introduction and manipulation of the interbody cage 1 between the vertebral bodies of the above and underlying vertebrae VS, VI of a column spinal.

The threaded bore 13 is provided to open inside the internal space 3 of the body 2 of the interbody cage 1.

The body 2 comprises, at the junction between the lateral faces 6, 7 with the rear face 9 and on either side of the bore 13, two notches 15 and 16 opening out or not inside the internal space 3 of the body 2 of the interbody cage 1.

The body 2 of the intersomatic cage 1 comprises at the front face 8 a first marker 17 arranged in a vertical direction and at the rear face 9 a second marker 18 placed in a horizontal direction and perpendicular to the first.

The first marker 17 is positioned at the front of the interbody cage 1 and centered on the main axis of the latter so that the distance between the internal and external faces is identical.

The second marker 18 is positioned in a horizontal direction which is offset from the main axes of the rear face 9 or of the threaded bore 13 of the interbody cage 1.

The offset of the second marker 18 on the rear face 9 allows the radiographic location between the right and left interbody cage during a front view of the spine of a patient (Figure 2).

Indeed the intersomatic cage 1 according to the present invention is reversible, that is to say, which is likely to be implanted between the vertebral bodies to the right and to the left of the vertical axis passing through the vertebrae of the spine. Also during a profile view, the position of the markers 17 and 18 between the two intersomatic cages 1 implanted between the vertebral bodies VS, VI makes it possible to verify the respective penetration of the two cages between them (FIG. 3).

Note that in the side view the intersomatic cage 1 on the right is the one with the marker 18 in the high position, while the intersomatic cage 1 on the left is identified by the marker 18 being in the lowest position.

This positioning on the right and left of the intersomatic cage 1 is obtained by a simple rotation of the latter around its longitudinal axis so that each inner face 6 of smaller radius of curvature is always arranged one opposite the other.

The markers 17, 18 are produced in a cylindrical wire or of another geometric shape crossing right through the intersomatic cage 1.

The markers 17, 18 are made of a material capable of being visible during an X-ray image so as to allow the position of the intersomatic cages 1 to be viewed with respect to and with respect to the vertebral bodies of the above and underlying vertebrae VS, VI of a spine.

Indeed, it is generally introduced between the vertebral bodies of the overlying and underlying vertebrae VS, VI of a vertebral column two intersomatic cages 1 which are positioned relative to each other so that the internal lateral faces 6 are arranged one opposite the other.

Thus, the markers 17 and 18 make it possible to verify the position of the two cages with respect to each other and to identify the right cage of the left cage when they are introduced between the vertebral bodies of the above and underlying vertebrae VS , VI of a spine (Figures 2, 3).

It is noted that during a front view of the spine it is placed between the vertebral bodies of the vertebrae above and below VS, VI a cage 1 on the right and a cage on the left of the vertical axis of said spine.

Thus, the intersomatic cage 1 called on the right is identified by the position of the markers 17, 18, the second of which 18 is located above the threaded bore 13 formed in the rear face 9 (FIG. 2). The intersomatic cage 1 called on the left is identified by the position of the markers 17, 18, the second of which 18 is located below the threaded bore 13 formed in the rear face 9 (FIG. 2).

Thus, we see that the interbody cage 1 is reversible to be positioned either on the right or on the left and between the vertebral bodies of the above and underlying vertebrae VS, VI of a spine

There is shown in Figures 4 to 7 a tool 14 for the establishment and introduction of the interbody cage 1 between the vertebral bodies of the vertebrae above and underlying VS, VI of a spine by means of a follower rod 21.

The tool 14 consists of a grip handle 19 integral with a tube 20 having in its internal part a first bore 31 which is extended by a second bore 32 whose internal diameter is less than that of the first.

The handle 19 has a housing 22 inside which a knurl 23 rotates in rotation so as to drive inside the bore 31 of the tube 20 a rod 24. The housing 22 is closed above the wheel 23 by a plate 25 forming a striking zone on the tool 14.

The tube 20 has, opposite the handle 19, pins 26, while its internal bore 32 has a part 33 with a hexagonal profile or the like.

The rod 24 is fixed to the wheel 23 by means of a clamping screw 34, while it has, opposite the wheel 23, a threaded bore 27. The follower rod 21 has a threaded portion 28 and at opposite the latter a hexagonal or similar profile 29 extending by a threaded end 30.

The tools 14 which have at the end opposite to that of the handle 19 an intersomatic cage 1 have been shown in FIGS. 6 to 7.

The follower rod 21 is assembled so that its threaded end 30 cooperates with the threaded bore 13 provided in the rear face 9 of the body 2.

The follower rod 21 is rotated by means of the hexagonal profile 29 so that the interbody cage 1 is perfectly maintained at the end of the latter.

Then the follower rod 21 is assembled to the tool 14 so that its threaded part 28 cooperates with the threaded bore 27 of the rod 24. The fixation of the follower rod 21 is obtained by the rotary drive of the rod 24 by the wheel 23 located at the handle 19 of the tool 14.

The rotation of the rod 24 makes it possible to introduce the follower rod 21 inside the internal bore 32 of the tube 20 until the hexagonal profile 29 cooperates with the part with complementary profile 33 of said tube.

The translational movement of the follower rod 21 inside the tube 20 is carried out until the lugs 26 penetrate inside the notches 15 and 16 provided at the rear face 9 of the interbody cage 1 ( Figures 8, 9).

The cooperation of the pins 26 of the tube 20 with the notches 15, 16 of the interbody cage 1 allows the locking in rotation of the follower rod 21 inside said tube. Thus, the surgeon can introduce between the vertebral bodies of the above and underlying vertebrae VS, VI of a spinal column the first interbody cage 1 using the tool 14.

This introduction can for example be formed by successive strikes carried out using a hammer on the plate 25 without risk of blocking the threaded parts of the tool 14 with the follower rod 21 and the latter with the interbody cage 1. As soon as the first intersomatic cage 1 is introduced, the surgeon withdraws the tool 14 by rotating the wheel 23 to release the follower rod 21 locked in rotation by the complementary profiles 29, 33 from the rod 24 guided inside the tube 20.

After removing the tool 14, it can be seen that the follower rod 21 remains assembled with the first interbody cage 1. Thus, the surgeon can visually identify the position of the interbody cage 1 between the vertebral bodies of the above and underlying vertebrae VS , VI of a vertebral column thanks to the follower rod which leaves the operating field.

Also, the surgeon can act on the follower rod 21 to change the position of the interbody cage 1 between the vertebral bodies of the above and underlying vertebrae VS, VI of a vertebral column thanks to the follower rod which leaves the operating field.

The follower rod 21 is removed from the interbody cage 1 by means of its hexagonal profile 29 which allows it to be driven in rotation by any tool. It should moreover be understood that the foregoing description has been given only by way of example and that it in no way limits the field of the invention from which one would not depart by replacing the details of executions described by any other equivalent.

Claims

1. Device for setting up an intersomatic cage, characterized in that it comprises a tool (14) which consists of a grip handle (19) integral with a tube (20), a rod follower (21) guided and immobilized inside the tube (20) and assembly means which consist of a rod (24) guided inside a first bore (31) of the tube (20) , a thumbwheel (23) allowing the rod (24) to rotate, and a hexagonal profile (33) provided in a second bore (32) of said tube for locking the follower rod in rotation ( 21) inside the tube (20). 2. Positioning device according to claim 1, characterized in that the handle (19) has a housing (22) inside which rotates the wheel (23) in order to drive inside the 'bore (31) of the tube (20) the rod (24), the housing (22) is closed above the wheel (23) by a plate (25) forming a striking area on the tool (14). Positioning device according to claim 1, characterized in that the follower rod (21) has a threaded part (28) and opposite this latter a hexagonal profile or the like (29) extended by a threaded end ( 30). Positioning device according to claim 1, characterized in that the tube (20) comprises, opposite the handle (19), lugs (26). 5. Installation device according to claim 1, characterized in that the tube (20) has in its internal part a first bore (31) which is extended by a second bore (32) whose internal diameter is less than that from the first.