Patent ID: 8012178
Filing Date: 2011-09-06
Classification: A61B

Abstract:
1. A device for dynamic stabilization of vertebral bodies, the device comprising: at least a first and second bone anchoring device each having a head segment; and an elastic means having a first end section, a second end section and a longitudinal axis, the first end section of the elastic means connectable to the head segments of the first bone anchoring device and the second end section of the elastic means connectable to the head segment of the second bone anchoring device such that the longitudinal axis extends between the first and second bone anchoring devices, wherein: the elastic means is made of a metallic material and comprises a plurality of helical spring coils having a pitch δ, at least two of the spring coils have at least one geometric dimension which is different than the other of the spring coils, and the pitch of the spring coils varies continuously along the longitudinal axis, and under a compressive load, the elastic means has a progressive spring characteristic, wherein the pitch of the helical spring coils increases from center towards the ends of the plurality of helical spring coils.