Prosthesis (i.e. – artificial body members) – parts thereof – or ai – Implantable prosthesis – Bone
Patent
1994-09-06
1996-04-16
Isabella, David
Prosthesis (i.e., artificial body members), parts thereof, or ai
Implantable prosthesis
Bone
606 61, A61F 244
Patent
active
055078168
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to a spinal implant, an implant and a spine incorporating an implant. The invention is particularly but not exclusively applicable to implants for spinal vertebrae such as human vertebrae.
A spinal vertebral disc replacement would be performed when one of the discs which lie between the bodies of the vertebrae, has become damaged or dislocated giving rise to what is commonly known as a "slipped disc". These cases tend to be treated by removing the old disc and packing the space with bone chips. The disadvantages of this method are the unreliability of the results and the loss of mobility experienced by the patient in the lower back.
The aim of a spinal disc prosthesis is to replace the damaged disc while maintaining function and stability in the patients back. There are at present very few spinal disc replacement systems available in the world. They comprise generally of a pair of metal plates, one of which is placed on the upper of the two vertebrae and the other on the lower. A polyethylene bearing is then pushed between the plates to provide stability with a degree of motion. The problems of existing systems are that the polyethylene component tends to be contoured (convex) on both sides which enables it to locate in two concave depressions, one each in the centre of the two plates. This requires that both plates be exactly in line with each other of the polyethylene insert cannot be located. In order that alignment can be consistently achieved, it is necessary to have complex instrumentation which makes the operation difficult to perform. The second major problem with existing systems is one of fixation of the metal plates to the bone of the vertebrae. Although once in place the components are under constant compression, this does not prevent rotation of the plates or sideways movement, both of which are extremely undesirable. To date this problem has been addressed by having small spikes on the back of the metal plates which are embedded in the bone. These however do not provide good fixation and could easily work loose, neither do they allow for any bony integration with the implant.
According to one aspect of the present invention a method of securing an implant into an animal bone comprises removing a portion of the bone of form a first pair of spaced opposed generally planar abutment surfaces which face each other and locating the implant such that the implant engages with the abutment surfaces to restrict movement of the implant relative to the bone in a direction towards either abutment surface.
The abutment surfaces may be substantially parallel to each other.
The method may comprise removing substantially all of the bone between the abutment surfaces and locating the implant to substantially fill the space between the abutment surfaces.
The method may comprise removing a portion of the bone to form a second pair of spaced opposed abutment surfaces which extend at an angle to the first pair of abutment surfaces and locating the implant such that the implant engages with the second pair of abutment surfaces to restrict movement of the implant in the direction towards either of the second pair of abutment surfaces.
A second pair of spaced opposed abutment surfaces may face each other. The second pair of abutment surfaces may be formed by a rotating drill.
The second pair of abutment surfaces may be located in a part of the bone which is exposed only after the formation of the first pair of abutment surfaces.
The method may comprise forming a first pair or a first and second pair of abutment surfaces as previously referred to in a second bone with a different component of the implant being arranged to engage with the first or the first and second abutment surfaces.
The method may comprise securing the implant to a vertebrae such as a human vertebrae.
The present invention also includes a combination comprising a bone and an implant in which the implant has been secured by a method as herein referred to.
According to another aspect of the present invention an implant c
REFERENCES:
patent: 5002576 (1991-03-01), Fuhrmann et al.
Customflex Limited
Isabella David
LandOfFree
Spinal vertebrae implants does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Spinal vertebrae implants, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Spinal vertebrae implants will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-322110