Method and instruments to treat spondylolisthesis by an anterior minimally invasive approach of the spine

1 . A method of performing spondylolisthesis reduction, the method comprising the steps of:

inserting an interbody spacer between two vertebrae;

attaching a reduction plate to the two vertebrae by at least two screws, wherein the reduction plate includes an upper and lower borehole, and the at least one screw uses a stable plate-screw connection, and at least another screw is fixed to the other vertebra is a non-locking screw; and

driving the non-locking screw to reduce the vertebral slippage distance.

2 . The method of claim 1 , wherein the reduction plate is straight.

3 . The method of claim 1 , wherein the reduction plate is curved, in a pre-stressed condition.

4 . The method of claim 1 , wherein the reduction plate can be adjusted intraoperatively for anatomical alignment of the vertebrae.

5 . The method of claim 1 , wherein the reduction plate includes a central borehole for securing the interbody spacer to the reduction plate by a screw.

6 . A method of performing spondylolisthesis reduction, the method comprising the steps of:

inserting an interbody spacer between a first and second vertebrae;

attaching the interbody spacer to one of the first vertebrae;

attaching an outer support to the interbody spacer;

securing at least one bone screw into the second vertebra, wherein the at least one screw is supported and not fixed to an inner support and the outer support;

threading at least one translation screw to the inner support, wherein the at least one translation screw is supported by the outer support;

rotating the translation screw to reduce the vertebral slippage distance;

inserting at least one screw into the second vertebra and interbody spacer, wherein the interbody spacer is stably fixed to the other vertebra; and

removing the outer support.

7 . The method of claim 6 , wherein the inner support and outer support are U-shaped.

8 . The method of claim 6 , wherein reduction of the vertebral slippage occurs by pulling the second vertebra.

9 . The method of claim 6 , wherein reduction of the vertebral slippage occurs by pushing the second vertebra.

10 . A method of performing spondylolisthesis reduction, the method comprising the steps of:

inserting an interbody spacer between two vertebrae, wherein the interbody spacer consists of a first member, a second member and an adjusting mechanism;

attaching the first member and second member to the vertebrae by locking screws; and

manipulating the adjusting mechanism such that the first member and second member move laterally with respect to each other, thereby aligning the vertebrae.

11 . A method of performing spondylolisthesis reduction on a first and second vertebrae, the method comprising the steps of:

inserting at least one screw into the first vertebrae,

fixing at least one screw to the second vertebra and to an external rigid element; and

using an adjustable mechanism to adjust the screw inserted into the second vertebra until a slippage distance of the second vertebra is reduced,

wherein the method is performed externally from an incision area.