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 of performing an endoscopic procedure in an intervertebral disc space through a Kambin's triangle of a human, the method comprising the steps of:
inserting a guide member through tissue of the human toward the intervertebral disc space along a generally transforaminal approach along a trajectory;
applying an electrical current to the guide member during the inserting step; and
during the applying step, determining that the guide member is approaching a nerve as the guide member is inserted through the tissue of the human during the inserting step;
changing the trajectory to a changed trajectory, and driving the tube through tissue of the human toward the intervertebral disc space along the changed trajectory along the generally transforaminal approach toward the Kambin's triangle;
introducing at least one dilator tube over the guide member;
introducing an access cannula over the at least one dilator tube;
removing the guide member and the at least one dilator tube; and
performing the endoscopic procedure in the intervertebral disc space through the access cannula and through the Kambin's triangle.
2. The method claim 1 , wherein the determining step comprises determining that a nerve of the Kambin's triangle has been stimulated by the electrical current when the electrically conductive instrument approaches the nerve.
3. The method of claim 2 , wherein the determining step comprises the step of visually observing a visual indication that the guide member is approaching the nerve.
4. The method of claim 3 , wherein the changing step removes the visual indication.
5. The method of claim 4 , wherein the visual indication comprises a movement of a leg of the human.
6. The method of claim 1 , wherein the driving step comprises driving the tube along a changed trajectory that extends through the Kambin's triangle.
7. The method of claim 6 , wherein the step of performing the foraminoplasty comprises rotating a bone cutting instrument so as to remove bone.
8. The method of claim 1 , comprising the step of performing a foraminoplasty under endoscopic visualization prior to the step of performing the endoscopic procedure.
9. The method of claim 8 , wherein the step of rotating the bone cutting instrument comprises rotating the bone cutting instrument about an axis that extends along the changed trajectory.
10. The method of claim 9 , wherein the endoscopic procedure comprises removing disc material from the intervertebral disc space.
11. The method of claim 1 , wherein the at least one dilator tube comprises a plurality of dilator tubes, and the step of introducing the access cannula comprises introducing the access cannula over a largest one of the plurality of dilator tubes.
12. The method of claim 1 , wherein the endoscopic procedure comprises inserting an intervertebral implant through the access cannula and into the intervertebral disc space, and subsequently expanding the intervertebral implant from a first height to a second height greater than the first height.
13. The method of claim 1 , wherein the applying step comprises applying a constant current to the guide member.
14. The method of claim 1 , wherein the applying step comprises varying an amount of the current to the guide member.
15. The method of claim 1 , further comprising the step of attaching a pedicle screw to a pedicle of a vertebra.