Method and apparatus for minimally invasive insertion of intervertebral implants
A dilation introducer for orthopedic surgery is provided for minimally invasive access for insertion of an intervertebral implant. The dilation introducer may be used to provide an access position through Kambin's triangle from a posterolateral approach. A first dilator tube with a first longitudinal axis is provided. A second dilator tube may be introduced over the first, advanced along a second longitudinal axis parallel to but offset from the first. A third dilator tube may be introduced over the second, advanced along a third longitudinal axis parallel to but offset from both the first and the second. An access cannula may be introduced over the third dilator tube. With the first, second, and third dilator tubes removed, surgical instruments may pass through the access cannula to operate on an intervertebral disc and/or insert an intervertebral implant.
1. A method for performing orthopedic surgery, comprising:
introducing an access cannula to a Kambin's triangle; and
inserting an intervertebral implant through the access cannula into an intervertebral space through the Kambin's triangle in an unexpanded state along an insertion direction, wherein the implant includes an upper body portion defining a substantially planar top surface configured to bear against a superior vertebral body, and a lower body portions defining a substantially planar bottom surface opposite the top surface and configured to bear against an inferior vertebral body, and the implant defines a height from the top surface to the bottom surface; and
after the inserting step, expanding the intervertebral implant, such that the height of the implant after the expanding step is greater than the height of the implant before the expanding step and after the inserting step.
2. The method of claim 1 , further comprising the step of enlarging the Kambin's triangle prior to the inserting step.
3. The method of claim 2 , wherein the step of enlarging the Kambin's triangle comprises removing bone from a superior edge of a vertebra.
4. The method as recited in claim 2 , wherein the step of enlarging the Kambin's triangle comprises rotating a bone cutting instrument.
5. The method of claim 1 , further comprising the step of introducing a first instrument through the Kambin's triangle, wherein the step of introducing the access cannula further comprises introducing the access cannula over the first instrument.
6. The method of claim 5 , wherein the first instrument comprises a dilator tube.
7. The method of claim 6 , further comprising the step of removing the dilator tube after the second introducing step and prior to the inserting step.
8. The method of claim 1 , wherein the expanding step causes both the top and bottom surfaces to bear against the upper and lower vertebrae, respectively.
9. The method of claim 1 , wherein the implant defines a length along the insertion direction that is perpendicular to the height, and a width that is less than the length, the width being measured perpendicular to each of the insertion direction and the height.
10. The method of claim 9 , wherein the implant defines a single upper body portion that defines an entirety of the top surface, and a single lower body portion that defines an entirety of the bottom surface, and the expanding step causes at least one of the upper and lower body portions to move away from the other of the upper and lower body portions.
11. The method of claim 10 , wherein the expanding step comprises moving first and second wedge members relative to each other so as to cause the upper and lower body portions to move away from each other.
12. The method as recited in claim 1 , further comprising removing disc material from the intervertebral space prior to the inserting step.
13. The method as recited in claim 1 , further comprising driving a dilation tube toward the Kambin's Triangle, and the introducing step comprises inserting the access cannula over the dilation tube.
14. The method as recited in claim 13 , wherein the dilation tube comprises a plurality of dilation tubes, the method comprising the step of driving the plurality of dilation tubes toward the Kambin's triangle, and the introducing step comprises inserting the access cannula over a largest one of the plurality of dilation tubes.
15. The method as recited in claim 1 , further comprising the step of implanting a pedicle screw to a pedicle of a vertebra.
16. The method as recited in claim 1 , further comprising, prior to the introducing step, the step of driving creating the path that extends through the Kambin's Triangle and toward the intervertebral space.