Abstract: Devices and associated methods help surgeons assess spinal and artificial disc replacement (ADR) position, orientation and motion. The device moves the spine through flexion, extension, lateral bending, and/or axial rotation while measuring the amount of movement in these directions. The device may also measures the force required to move the spine in one or more of the above-mentioned directions. The various disclosed embodiments maximize motion through careful alignment, size, location in the disc space, configuration of the articulating surfaces of the ADR, and adequate soft tissue release. The invention may utilizes pre-operative images to determine the preferred alignment of the ADR; intra-operative images to align the instruments, trial ADRs and the ADR; devices that assess the ROM of the vertebrae after soft tissue release; devices that determine the proper size of the ADR; devices that test the motion after machining the vertebrae; or ADR embodiments with different degrees of axial rotation.

Abstract: Methods and apparatus facilitate artificial disc replacement (ADR) removal. One aspect of the invention fastens ADR removal instruments to the ADR. The robust connection between the novel removal tools and the ADR allow the application of large forces. A second aspect of the invention provides special osteotomes, chisels, saws, and drills to release the ADR from the vertebrae. A guide system minimizes destruction of the vertebrae. A third aspect of the invention is directed to marking the location of spikes, keels, or other ADR projections on the front or other visible portion of the ADR. A fourth aspect of the invention involves the use of optional releasable spikes, fins, keels, or other projections. A fifth aspect of the invention resides in cement removal techniques and tools to remove cemented ADRs.