Apparatus for use in spinal surgery

#Described here are deformable, monolithic, stabilization devices, or implants, suitable for use within bone and between bones, for instance, to fuse vertebral bodies, to repair herniated discs, or to repair spinal compression fractures. The implants are introduced into a chosen site at a first, smaller height and then plastically deformed to achieve a second, but unique, pre-selected, larger height. Variations of the device provide one or more specific larger heights. The devices are particularly suitable as intervertebral spinal fusion implants for the immobilization of adjacent vertebral bodies. Methods of deploying the implants are also described as are instruments for such deployment.

#Also described are variations of the device particularly suitable as sizing instruments. These versions are elastic, i.e., not plastically deformable, and may be restored to their original size. Many of the described variations include deformable regions serving as hinges. Other variations are non-monolithic or may have one or more classical hinges substituted for the deformable regions.

#Some conditions of the spine result from degradation or injury to the bone structures, e.g., the vertebral bodies, of the spine. These conditions may be the result of bone degeneration such as by osteoporosis or trauma, or by injuries such as compression fractures. Any of these maladies can cause great pain.

#FIGS. 1A-1C show perspective views of one variation of the implant, respectively, in collapsed form, partially expanded form, and fully expanded form.

#FIGS. 2A and 2B are schematic drawings showing operation of some variations of the implant.

#FIGS. 3A and 3B show perspective views of one variation of the implant, respectively, in collapsed form and fully expanded form.

#Described herein is a bone stabilization device that may be used in an interosseous space, i.e., inside a bone or between bones, where the space is defined generally as being directly or indirectly between bony surfaces. In particular, the described device is suitable as an intervertebral spinal fusion implant that is introduced at a low profile and expanded to a high profile at the implantation site. The implant may be monolithic and expanded by deformation of the monolithic body. In many variations, the implant may be expanded to a unique preselected height. Other variations of the implant may be expanded to a specific, discrete height selected from two or more unique preselected heights. Expansion of the implant from the low profile rotates components of one or more, partial, load-bearing, integral, support columns into alignment upon reaching the final high profile. The expansion takes place in a single plane or single direction. The components of the support columns may latch to each other or otherwise interact or engage with each other to limit the expansion to the specific, discrete, predetermined heights or to lock the implant into the expanded configuration while providing high compressive strength to the implant.

#Described here are monolithic implants that are expanded from a lower height to a higher one by permanent, plastic deformation of the implant in a particular plane. The implant incorporates partial support components that become aligned during the process of deformation (and expansion) and cooperate to form a complete support component that typically supports a major portion of stress applied to the implant. In some variations of the implant, there may be a small gap between the partial support components after expansion; the small gap may disappear upon compression during use.

#FIGS. 1A-1C show a variation of the implant showing the generalized expansion by deformation and providing a set of common terms for components of the implant and its geometry.