Intervertebral prosthesis placement instrument
The invention concerns an intervertebral prosthesis placement instrument which can be used to facilitate accurate positioning of a spinal disc prosthesis between adjacent spinal vertebrae. The instrument has opposed jaws formed with tips that are shaped for insertion between the vertebrae. The jaws can be moved apart from on another to distract the vertebrae, allowing the prosthesis to enter between the vertebrae. The jaws also have opposed surfaces which are shaped to embrace the prosthesis between them and to guide the prosthesis into position.
1. A method for implanting an intervertebral prosthesis, the method comprising:
inserting a prosthesis having two vertebral contacting surfaces and at least one straight fin projecting from at least one of the two vertebral contacting surfaces into a placement instrument comprising opposed jaws, with the at least one fin slidably received in at least one straight slot in the opposed jaws;
inserting tips of the opposed jaws between adjacent vertebrae;
moving the jaws apart from one another to cause distraction of the vertebrae; and
implanting the prosthesis by sliding the at least one straight fin of the prosthesis in the at least one straight slot of the jaws and guiding the at least one straight fin of the prosthesis into a slot cut into one of the vertebrae.
2. A method according to claim 1 , wherein the step of moving the jaws apart from one another is performed by driving the prosthesis downward in the jaws to force the jaws and the vertebrae apart.
3. A method according to claim 1 , wherein the at least one straight fin comprises a straight fin on each of the two vertebral contacting surfaces and the at least one straight slot comprises a straight slot on each of the opposing inner surfaces of the jaws.
4. A method according to claim 1 , further comprising an initial step of cutting the slot into one of the vertebrae.
5. A method according to claim 1 , wherein the prosthesis is implanted by sliding the implant straight into a space between adjacent vertebrae.
6. A method according to claim 1 , wherein the at least one straight slot comprises two substantially parallel side walls, wherein the at least one straight fin comprises two substantially parallel side walls and the spacing of the side walls of the at least one straight slot are configured fit and guide the at least one straight fin.
7. A method for implanting an intervertebral prosthesis, the method comprising:
providing a placement instrument comprising opposed jaws and at least one straight slot in the opposed jaws configured to receive a straight fin of a prosthesis;
inserting tips of the opposed jaws between adjacent vertebrae;
moving the jaws apart from one another to cause distraction of the vertebrae;
inserting a prosthesis having two vertebral contacting surfaces and at least one straight fin into the placement instrument with the at least one straight fin of the prosthesis received in the at least one straight slot of the jaws; and
implanting the prosthesis by sliding the at least one straight fin of the prosthesis in the at least one straight slot of the jaws and guiding the at least one straight fin of the prosthesis into a slot cut into one of the vertebrae.
8. A method according to claim 7 , wherein the step of moving the jaws apart from one another is performed by manipulation of a pair of handles of the placement instrument.
9. A method according to claim 7 , wherein the at least one straight fin comprises a straight fin on each of the two vertebral contacting surfaces and the at least one straight slot comprises a straight slot on each of the opposing inner surfaces of the jaws.
10. A method according to claim 7 , further comprising an initial step of cutting the slot into one of the vertebrae.
11. A method according to claim 7 , wherein the at least one straight slot comprises two substantially parallel side walls, wherein the at least one straight fin comprises two substantially parallel side walls and the spacing of the side walls of the at least one straight slot are configured fit and guide the at least one straight fin.