SPINOUS PROCESS STABILIZATION DEVICE AND METHOD

摘要

A fixation device to immobilize a spinal motion segment and promote posterior fusion, used as stand-alone instrumentation or as an adjunct to an anterior approach. The device functions as a multi-level fusion system compromised of modular single-level implementations. At a single-level the implant includes a pair of plates spanning two adjacent vertebrae with embedding teeth on the medially oriented surfaces directed into the spinous processes or laminae. The complimentary plates at a single-level are connected via a cross-post with a hemi-spherical base and cylindrical shaft passed through the interspinous process gap and ratcheted into an expandable collar. The expandable collar's spherical profile contained within the opposing plate allows for the ratcheting mechanism to be correctly engaged creating a uni-directional lock securing the implant to the spine when a medially directed force is applied to both complimentary plates using a specially designed compression tool. The freedom of rotational motion of both the cross-post and collar enables the complimentary plates to be connected at a range of angles in the axial and coronal planes accommodating varying morphologies of the posterior elements in the cervical, thoracic and lumbar spine. To achieve multi-level fusion the single-level implementation can be connected in series using an interlocking mechanism fixed by a set-screw.