Expandable intevertebral cage
Disclosed herein are systems and methods for intervertebral body fusion that provide more robust support within the disc space. Intervertebral body fusion devices can have a unitary monolithic body including a plurality of body segments interconnected with each other by flexure members. Devices can be configured to be inserted through an opening in a compressed configuration and then expanded within the disc space to an expanded configuration. In the expanded configuration, devices can have a greater mediolateral or transverse to the disc space footprint. This wider footprint provides greater support for the vertebrae relative to the size of the opening through which the device is inserted. Changes between the expansion and compression configurations can be controlled based on the temperature of the device.
1 . An expandable intervertebral body fusion device, comprising:
a unitary monolithic body having a plurality of body segments coupled to each other with flexure members and an opening defined between the plurality of body segments;
a first locking bushing extending from a first end body segment into the opening;
a second locking bushing extending from a second end body segment into the opening; and
wherein the body is configured to be mediolaterally expanded from a compressed configuration to an expanded configuration causing the plurality of body segments to generally move away from each other to expand the opening between the plurality of body segments such that the body forms a greater mediolateral footprint in the expanded configuration than in the compressed configuration, and wherein the first and second locking bushings are brought together within the opening and further expansion of the body is prevented by the interaction between the first and second locking bushings,
wherein the first locking bushing or the second locking bushing are attached to the body with an expansion tool, the device further comprising a plurality of locking bushings having different axial lengths, wherein each different axial length is configured to permit a predetermined amount of expansion of the body.
2 . The expandable intervertebral body fusion device of claim 1 , wherein the intervertebral body fusion device is constructed by wire EDM.
3 . An expandable intervertebral body fusion device, comprising:
a unitary monolithic body having a plurality of body segments coupled to each other with flexure members and an opening defined between the plurality of body segments, including:
a first end body segment having a portion extending into the opening; and
a second end body segment having a portion extending into the opening; and
wherein the body is configured to be mediolaterally expanded from a compressed configuration to an expanded configuration to expand the opening between the plurality of body segments such that the body forms a greater mediolateral footprint in the expanded configuration than in the compressed configuration, and wherein the portion of the first end body segment extending into the opening and the portion of the second end body segment extending into the opening are brought together within the opening to prevent further expansion of the body.
4 . The expandable intervertebral body fusion device of claim 3 , wherein the portion of the first end body segment extending into the opening and the portion of the second end body segment extending into the opening interlock together.
5 . The expandable intervertebral body fusion device of claim 3 , wherein the first end body segment and second end body segment each define an opening configured to receive an expansion tool therethrough.
6 . The expandable intervertebral body fusion device of claim 3 , where the first end body segment and the second end body segment each define an open interior configured to receive bone growth material therein.
7 . The expandable intervertebral body fusion device of claim 3 , wherein the plurality of body segments form tongue and groove connections with each other in the expanded configuration.
8 . The expandable intervertebral body fusion device of claim 7 , wherein the tongue and groove connections provide the body with increased resistance to shear and torsional forces.
9 . The expandable intervertebral body fusion device of claim 3 , wherein the portion of the first end body segment extending into the opening and the portion of the second end body segment extending into the opening prevent damage to the body from overexpansion.