Patent ID: 8613758

Claim:
An expandable spinal jack adapted for insertion between succeeding spinal vertebrae, comprising: assembleable upper and lower portions, each portion exhibiting a concave exterior configured for seating against an opposing location of an articular process associated with first and second successive vertebrae; an annular projection integrally formed with and downwardly extending from an underside of said upper portion, said annular projection being received in seating fashion within an annular aligning sleeve extending upwardly from said lower portion; a plurality of coil springs seating within the annular aligning sleeve, said coil springs influencing an underside of said annular projection in an upward direction; and an adjustment mechanism established within an enclosed interior surrounded by said annular aligning sleeve and projection, said adjustment mechanism including a first component extending downwardly from said upper portion and a second component extending upwardly from said lower component in length adjustable engagement with said first component, wherein said first component includes at least one stem, said stem including seating portions integrally formed on an underside of said stem, said second component including a rotatable step ring having stem engagement locations formed in a stepped pattern, wherein rotation of said step ring causes upward reseating of said stem in order to define a range of separation distances between said upper and lower portions.