Bi-directional fixating transvertebral body screws, zero-profile horizontal intervertebral miniplates, expansile intervertebral body fusion devices, and posterior motion-calibrating interarticulating joint stapling device for spinal fusion

An artificial intervertebral implant comprising:

• a fusion cage comprising a top wall, a bottom wall, a first sidewall, and a second sidewall, wherein the top wall, bottom wall, first sidewall, and second sidewall together define a first vertebral body facing surface and a second vertebral body facing surface opposite of the first vertebral body facing surface, wherein the top wall comprises a top surface extending from the first sidewall to the second sidewall, wherein the top surface is a substantially flat surface between the first and second sidewalls and between the first and second vertebral body facing surfaces, wherein each of the bottom wall and the first and second sidewalls are at least partially curved when viewed from a direction facing the first vertebral body facing surface such that the bottom wall along with the first and second sidewalls together substantially form a U-shape when viewed from a direction facing the first vertebral body facing surface, wherein the top wall is substantially straight when viewed from the direction facing the first vertebral body facing surface, wherein the fusion cage defines at least one bone material slot extending from the first vertebral body facing surface through the fusion cage to the second vertebral body facing surface, wherein the at least one bone material slot is bounded between the top wall and the bottom wall;
• a first anchor having a first anchor body and a first tapered tip, wherein the first anchor body has a first plurality of outwardly-extending bone engagement ridges, wherein the first anchor body is curved along the first anchor body, wherein the first anchor is extendable from the fusion cage to a first anchored position with the first tapered tip and the first plurality of outwardly-extending bone engagement ridges extending out of the fusion cage past the first vertebral body facing surface;
• and
• a second anchor having a second anchor body and a second tapered tip, wherein the second anchor body has a second plurality of outwardly-extending bone engagement ridges, wherein the second anchor body is curved along the second anchor body, wherein the second anchor is extendable from the fusion cage to a second anchored position with the second tapered tip and the second plurality of outwardly-extending bone engagement ridges extending out of the fusion cage past the second vertebral body facing surface,
• wherein the first and second anchors are configured to be sequentially extended out of the fusion cage in opposite directions such that the first anchor can be extended from the fusion cage past the first vertebral body facing surface prior to extending the second anchor out of the fusion cage past the second vertebral body facing surface and wherein the first and second anchors are aligned with one another when extended such that the first tapered tip of the first anchor is positioned opposite and aligned with the second tapered tip of the second anchor,
• wherein the top wall defines a plurality of tool engagement holes that extend through the top surface of the top wall and are configured to facilitate operable engagement between at least one tool that extends along an axis that is substantially perpendicular to the top wall of the fusion cage with the first and second anchors to sequentially advance each of the first and second anchors out of the fusion cage through aligned and opposing openings defined by the first and second vertebral body facing surfaces such that the first tapered tip of the first anchor is positioned opposite and aligned with the second tapered tip of the second anchor.