Dynamic Spacer Device and Method for Spanning a Space Formed upon Removal of an Intervertebral Disc
A compliant intervertebral spacer according to the present invention replaces a damage intervertebral disc and functions to maintain disc height and prevent subsidence with a large surface area while substantially reducing patient recovery time. The compliant intervertebral spacer for spanning a space formed by upon removal of an intervertebral disc includes two end plates sized and shaped to fit within an intervertebral space and a compliant connector interconnecting the inner surfaces of the two end plates in a manner which limits motion between the plates to less than a total of 5 degrees of motion in any direction. The intervertebral spacer is configured to permanently maintain the disc space between the two adjacent discs without the use of bridging bone.
1 . A method of spanning a space formed by upon removal of an intervertebral disc, the method comprising:
performing a discectomy to remove disc material between two adjacent vertebral bodies;
placing an intervertebral spacer between the two adjacent vertebral bodies, the spacer comprising two end plates, each end plate having a vertebral body contacting surface and an inner surface, and a connector interconnecting the inner surfaces of the two end plates in a compliant manner which limits motion between the plates to less than a total of 5 degrees of motion in any direction; and
maintaining the disc space between the two adjacent vertebral bodies with the intervertebral spacer without the use of bone graft or bridging bone.
2 . The method of claim 1 , wherein the connector is a compliant connector which allows axial motion between the two end plates.
3 . The method of claim 2 , wherein the axial motion is limited to less than 2 mm.
4 . The method of claim 1 , wherein the connector is a complaint connector which allows rotation between the two end plates.
5 . The method of claim 2 , wherein the compliant connector has a plurality of cuts formed therein to create a unitary flexible member.
6 . The method of claim 5 , wherein the two end plates and connector are formed of a single piece of metal.
7 . The method of claim 1 , further comprising cutting at least one slot in each of the adjacent vertebrae and placing a fin into the slot in each vertebrae.
8 . The method of claim 7 , wherein the intervertebral spacer is held in place between the adjacent vertebral bodies by a fixation means, and wherein the fixation means is at least one of a screw, serrations, teeth, pyramids or grooves.
9 . An intervertebral spacer for spanning a space formed by upon removal of an intervertebral disc, the spacer comprising:
two end plates sized and shaped to fit within an intervertebral space, each end plate having a vertebral body contacting surface an inner surface;
a connector interconnecting the inner surfaces of the two end plates in a compliant manner which limits motion between the plates to less than a total of 5 degrees of motion in any direction; and
wherein the intervertebral spacer is configured to permanently maintain the disc space between the two adjacent discs with the intervertebral spacer without the use of bridging bone.
10 . The spacer of claim 9 , wherein the connector is a compliant connector which allows axial motion between the two end plates.
11 . The spacer of claim 10 , wherein the axial motion is limited to less than 2 mm.
12 . The spacer of claim 9 , wherein the connector is a complaint connector which allows rotation between the two end plates.
13 . The spacer of claim 12 , wherein the compliant connector has a plurality of cuts formed therein to create a unitary compliant member.
14 . The spacer of claim 9 , wherein the two end plates and connector are formed of a single piece of metal.
15 . The spacer of claim 9 , wherein the connector limits motion between the plates to less than a total of 3 degrees of motion in any direction.
16 . The spacer of claim 9 , further comprising at least one fin extending from each of the vertebral body contacting surfaces.
17 . A method of spanning a space formed by upon removal of an intervertebral disc, the method comprising:
performing a discectomy to remove disc material between two adjacent vertebral bodies;
placing an intervertebral spacer between the two adjacent vertebral bodies, the spacer comprising two vertebral body contacting surfaces and the including means for limiting motion between the two vertebral body contacting surfaces to less than a total of 5 degrees; and
maintaining the disc space between the two adjacent vertebral bodies with the intervertebral spacer within the intervertebral space, wherein the vertebral body contacting surfaces have no holes therein or have holes which cover less than 40 percent of the vertebral body contacting surfaces.
18 . The method of claim 17 , wherein the intervertebral spacer allows axial motion between the two end plates.
19 . The method of claim 18 , wherein the axial motion is limited to less than 2 mm.
20 . The method of claim 17 , wherein the intervertebral spacer includes a compliant portion which allows rotation between the two end plates.
21 . The method of claim 20 , wherein the compliant portion has a plurality of cuts formed therein to create a unitary flexible member.
22 . The method of claim 17 , wherein the vertebral body contacting surfaces have holes which cover less than 25 percent of the vertebral body contacting surfaces.
23 . An intervertebral spacer for spanning a space formed by upon removal of an intervertebral disc, the spacer comprising:
a compliant spacer body sized and shaped to fit within an intervertebral space;
two opposite vertebral body contacting surfaces formed on the spacer body;
wherein the spacer body limits motion between the vertebral body contacting surfaces to less than a total of 5 degrees; and
wherein the vertebral body contacting surfaces have no holes therein or have holes which cover less than 40 percent of the vertebral body contacting surfaces.
24 . The spacer of claim 23 , wherein the compliant spacer body allows rotation between the two end plates.
25 . The spacer of claim 23 , wherein the compliant spacer body allows axial motion between the vertebral body contacting surfaces of less than 2 mm.
26 . The spacer of claim 23 , wherein the compliant spacer body has a plurality of cuts formed therein to create a unitary flexible member.
27 . The spacer of claim 23 , wherein the vertebral body contacting surfaces and the compliant spacer body are formed as a single unitary piece.
28 . The spacer of claim 24 , wherein the spacer body limits rotational motion between the plates to less than a total of 3 degrees in any direction.
29 . The spacer of claim 23 , further comprising at least one fin extending from each of the vertebral body contacting surfaces.
30 . The spacer of claim 23 , wherein the spacer has holes which cover less than 25 percent of the vertebral body contacting surfaces.
31 . The spacer of claim 23 , wherein the spacer body includes a plurality of transverse cuts which create a spring element.
32 . The spacer of claim 23 , wherein the spacer body includes at least one hole therein and a fixation screw received therein.
33 . A method of performing an anterior/posterior fusion, the method comprising:
performing a discectomy to remove disc material between two adjacent vertebral bodies;
anteriorly placing an intervertebral spacer between the two adjacent discs, the spacer comprising a compliant spacer body sized and shaped to fit within an intervertebral space and two opposite vertebral body contacting surfaces formed on the spacer body wherein the spacer body limits motion between the vertebral body contacting surfaces to less than a total of 5 degrees;
maintaining the disc space between the two adjacent discs with the intervertebral spacer;
adjusting an angle between the vertebral bodies posteriorly; and
posteriorly placing a stabilization system to fix the angle between the vertebral bodies.
34 . The method of claim 32 , wherein the posteriorly placed stabilization system includes at least one screw placed into each of the vertebral bodies and at least one connector therebetween.
35 . The method of claim 32 , wherein the method is performed without the use of bone graft.