Device for implantation for the purpose of limiting the movements between two vertebrae

Claim 1

A device for implantation for the purpose of limiting movements between two vertebrae (V1, V2), comprising at least two vertebra engaging elements (1a, 1 b; 11 a, 11 b) each having a free end (2a, 2b; 15a, 15b), and an elastic coupling element (3a, 3b, 4; 12) which is connected with the free ends (2a, 2b; 15a, 15b) of the vertebra engaging elements (1a, 1 b; 11 a, 11 b), the elastic coupling element (3a, 3b, 4; 12) being designed in such a manner that upon an increase of the distance between the free ends (2a, 2b; 15a, 15b) of the vertebra engaging elements (1 a, 1 b; 11 a, 11 b) starting from a neutral position the coupling element (3a, 3b, 4; 12) generates a force counteracting the increase and upon a decrease of the distance between the free ends (2a, 2b; 15a, 15b) of the vertebra engaging elements (1a, 1b; 11 a, 11 b) starting from the neutral position the coupling element (3a, 3b, 4; 12) generates a force counteracting the decrease.

Claim 2

A device for implantation for the purpose of limiting movements between two vertebrae (V1, V2), comprising at least two vertebra engaging elements (1a, 1 b; 11 a, 11 b) each having a free end (2a, 2b; 15a, 15b), and an elastic coupling element (3a, 3b, 4; 12) which is connected with the free ends (2a, 2b; 15a, 15b) of the vertebra engaging elements (1a, 1 b; 11 a, 11 b), the elastic coupling element (3a, 3b, 4; 12) being designed in such a manner that upon an increase of the distance between the free ends (2a, 2b; 15a, 15b) of the vertebra engaging elements (1 a, 1 b; 11 a, 11 b) starting from a neutral position the coupling element (3a, 3b, 4; 12) generates a force counteracting the increase and upon a decrease of the distance between the free ends (2a, 2b; 15a, 15b) of the vertebra engaging elements (1a, 1b; 11 a, 11 b) starting from the neutral position the coupling element (3a, 3b, 4; 12) generates a force counteracting the decrease.

Claim 6

A device according to any one of claims 1-4, characterized in that the coupling element (3a, 3b, 4) comprises two flexible pins (3a, 3b) which are each rigidly connected by one end with the free end (2a, 2b) of a vertebra engaging element (1 a, 1b) and are each connected at the other end with a rigid connecting member (4), each vertebra engaging element (1 a, 1b) at the free end (2a, 2b) thereof comprising an internal cavity (5) in which the pin (3a, 3b) extends at least partly, the internal surface of the cavity (5) serving to support the pin (3a, 3b) during the bending thereof.

Claim 9

A device according to any one of claims 5-7, characterized in that the rigid connecting member (4) is pivotally connected to the free ends of the two flexible pins (3a, 3b).

Claim 10

A device according to any one of claims 5-8, characterized in that the pins are designed as a bundle of substantially parallel wire-shaped elements.

Claim 11

A device according to any one of claims 1-4, characterized in that the coupling element (12) comprises a rigid connecting member (13) and two ball-and-socket joints (14a, 14b) each comprising a ball (15a, 15b) and a socket (16a, 16b), each ball (15a, 15b) in mounted condition being rigidly connected with an associated vertebra engaging element (11 a, 11 b), while each socket (16a, 16b) is slidably connected with the rigid connecting member (13) and in a neutral position is urged into an end position by biassed springing means (17a, 17b).

Claim 14

A device according to any one of claims 1-4, characterized in that the coupling element comprises at least one spring element, manufactured from springing wire or sheet material, which is provided with a curvature, the or each spring element being connected at free ends thereof with the free ends of the vertebra engaging elements.