Methods and Apparatus for Intervertebral Disc Prosthesis Insertion
A method for inserting an intervertebral disc prosthesis into a space between two vertebrae involves inserting the prosthesis partway into the space under constraint to prevent endplates of the prosthesis from articulating, releasing the prosthesis from constraint, and inserting the unconstrained prosthesis farther into the space. In some embodiments, the method involves grasping the prosthesis with a grasping device to insert the prosthesis partway under constraint, loosing the grasping device to release the prosthesis from constraint, and pushing the prosthesis farther into the disc space using the grasping device and/or one or more separate pusher devices. A system includes a grasping device, at least one separate pushing device, and optionally a vertebral spreading device and/or a vertebral midline indicator device.
1 . A device for inserting an intervertebral prosthesis into a space between two adjacent vertebrae, the device comprising:
an elongate rigid shaft having a proximal end and a distal end;
an adjustable grasping member coupled with the distal end for releasably grasping endplates of the intervertebral prosthesis such that the endplates are constrained from articulating and such that an outer diameter of the grasping member does not extend beyond a largest diameter of the endplates; and
an actuator disposed near the proximal end of the shaft and coupled with the grasping member for adjusting the grasping member to grasp and release the prosthesis,
wherein the grasping member is adapted for pushing the prosthesis into the space between the two vertebrae either while grasping the prosthesis or after releasing the prosthesis.
2 . A device as in claim 1 , wherein the grasping member is adapted to grasp the endplates such that they are prevented from articulating about a core of the prosthesis.
3 . A device as in claim 1 , wherein the grasping member comprises movable opposing jaws adapted to simultaneously grasp inner rims of the endplates.
4 . A device as in claim 1 , wherein the grasping member is coupled with the actuator via at least one rod extending through the shaft.
5 . A device as in claim 4 , wherein the grasping member comprises:
a first half coupled with a first movable rod extending from the actuator; and
a second half coupled with a second movable rod extending from the actuator.
6 . A device as in claim 5 , wherein the actuator comprises a thumb screw adapted to move the first and second rods closer together and farther apart by turning the thumb screw in opposite directions.
7 . A device as in claim 1 , wherein the actuator is selected from the group consisting of a thumb screw, a trigger, tongs and a movable handle.
8 . A device as in claim 1 , wherein the device is shaped to pass between two opposable jaws of a vertebral spacing device disposed between the two adjacent vertebrae.
9 . A device as in claim 1 , wherein the grasping member is adapted to push the endplates either simultaneously or individually into the space.
10 . A system for inserting an intervertebral prosthesis into a space between two adjacent vertebrae, the system comprising:
a prosthesis grasping device for grasping the prosthesis and pushing the prosthesis at least partway into the space, the grasping device comprising:
an elongate rigid shaft having a proximal end and a distal end;
an adjustable grasping member coupled with the distal end for releasably grasping endplates of the intervertebral prosthesis such that the endplates are constrained from articulating and such that an outer diameter of the grasping member does not extend beyond a largest diameter of the endplates; and
an actuator disposed near the proximal end of the shaft and coupled with the grasping member for adjusting the grasping member to grasp and release the prosthesis,
wherein the grasping member is adapted for pushing the prosthesis into the space between the two vertebrae while grasping the prosthesis and after releasing the prosthesis; and
at least one prosthesis pusher device for pushing the prosthesis farther into the space.
11 . A system as in claim 10 , wherein the pusher device comprises:
an elongate shaft having a proximal end and a distal end;
a concave pusher portion disposed at the distal end, the pusher portion adapted to push the endplates either simultaneously or individually into the space; and
a handle disposed at the proximal end.
12 . A system as in claim 10 , wherein the grasping member is adapted to grasp the endplates such that they are prevented from articulating about a core of the prosthesis.
13 . A system as in claim 10 , wherein the grasping member comprises movable opposing jaws adapted to simultaneously grasp inner rims of the endplates.
14 . A system as in claim 10 , wherein the grasping member is coupled with the actuator via at least one rod extending through the shaft.
15 . A system as in claim 14 , wherein the grasping member comprises:
a first half coupled with a first movable rod extending from the actuator; and
a second half coupled with a second movable rod extending from the actuator.
16 . A system as in claim 15 , wherein the actuator comprises a thumb screw adapted to move the first and second rods closer together and farther apart by turning the thumb screw in opposite directions.
17 . A system as in claim 10 , wherein the actuator is selected from the group consisting of a thumb screw, a trigger, tongs and a movable handle.
18 . A system as in claim 10 , wherein the device is shaped to pass between two opposable jaws of a vertebral spacing device disposed between the two adjacent vertebrae.
19 . A system as in claim 10 , wherein the grasping member is adapted to push the endplates either simultaneously or individually into the space
20 . A system as in claim 10 , further comprising a vertebral spacing device for increasing a height of the space between the two vertebrae, wherein the grasping member is adapted to slide through the vertebral spacing device disposed between the two adjacent vertebrae.
21 . A system as in claim 20 , wherein the pusher device is adapted to slide through the spacing device.