A prosthetic vertebra has a first hollow parallelepiped-shaped component and a second component shaped identically to the first component and marginally smaller than the first component. The second component can accordingly be positioned partially within the first component and can be axially moved within the first component, so that the overall length of the prosthetic vertebra can be established by appropriately moving the second component within the first. A set screw is threadably engageable with the first component and can be tightened against the second component to hold the components axially stationary relative to each other, once the prosthetic vertebra has been positioned in the patient and its length adjusted as appropriate to fit the patient.

An intervertebral locking device includes a bottom base, a bracing member, a top base, and at least one adjusting arm. The bottom base is provided on the upper surface thereof with a fastening member and on the lower surface thereof with one or more spikes. The bracing member has a bottom united with the fastening member attached to the upper surface of the bottom base. The top base is provided on the lower surface thereof with a fastening member and on the upper surface thereof with one or more spikes. The adjusting arm has one end serving as an adjusting end and another end acting as a locking end. The adjusting end of the adjusting arm is fastened to the bottom base or the top base in such a manner that the adjusting end is first adjusted to be in an appropriate position and is then fixed securely at that position. The locking end of the adjusting arm is fixed appropriately on one of the two vertebrae adjacent to a deformed or diseased vertebra under treatment.

A spinal facet prosthesis for a diseased or painful facet joint comprises a superior component and an inferior component. The superior component is roughly conical or pyramidal in form and is fastened to and over the distal tip of the inferior articular process of the diseased or painful facet joint. The inferior component is also roughly conical or pyramidal in form with one side elongated postero-medially and distally. The outer surface of the elongated side of the inferior component is of low friction, such as polished chromium coating or medical grade high-density polyethylene. The inferior component is fastened to and over the superior articular process of the diseased or painful facet joint. Each component is made of a biocompatible material. The inner surface of each component which is in contact with its respective articular process is coated with a porous coating to enhance the adhesion of each component to its respective articular process.

An intervertebral disc endoprosthesis which is to be inserted between two vertebrae and has a bottom plate and a top plate which are to be connected to the endplates, facing them, of the vertebrae additionally has screw fastening facilities in order to increase the security of retention of the prosthesis. These screw fastening facilities are formed, for example, by in each case at least one borehole which runs essentially at right angles to the plane of the bottom or top plate and through which a bone screw can be inserted. The center of articulation of the prosthesis is displaced towards the rear relative to the center of the vertebral endplates in order to achieve a more favorable course of the force and, at the same time, to provide space in the ventral edge area to receive the bone screws.

An intervertebral disk prosthesis for implantation between two adjacent vertebrae is disclosed which is more easily implantable intermediate the adjacent vertebrae, particularly from a posterior surgical approach, due to the two-piece construction of the intervertebral disk prosthesis. The intervertebral disk prosthesis of the present invention consists of first and second intervertebral disk segments which, when connected together by a bolt, together form a substantially elliptical configuration of a size fitting between the endplates of two adjacent vertebrae to maintain them in a properly spaced-apart and stable configuration which will be resistive to normal compressive forces exerted on the spine. Large apertures extending through the first and second intervertebral segments may be packed with bone chips or marrow prior to being implanted to facilitate bone ingrowth therethrough to fuse the aforesaid vertebrae together.