Spinal implant system
AssigneeCross Medical Products, Inc.
InventorsRolando M. Puno, Philip A. Mellinger
Life of this patent
Estimating the term…
Abstract
An apparatus is provided for the internal fixation of the spine. The apparatus comprises an assembly having at least two anchors and an elongated stabilizer. The anchors each have means to hold the anchor to the bone, and include receiving means which receive the stabilizer as well as securing means which cooperate with the receiving means by means of the interaction of mating threads to cause the application of compression on the stabilizer into the receiving means.
Claims7
A fixation device for the stabilization of one or more spinal bone segments, comprising:
- at least two anchors and an elongated stabilizer, said stabilizer having a cross-sectional depth, said anchors each comprising screw means which secure said anchor to said spinal bone segment;
- anchor seat means which has a lower bone interface surface which is operatively joined to said spinal bone segment by said screw means and has external threads on a portion spaced apart from said bone interface surface and said anchor seat means having an internal bore through which said screw means projects and the screw means has a rounded head which cooperates with said internal bore to permit limited motion between said screw means and said anchor seat means, said anchor seat means further having a stabilizer receiving channel with a stabilizer interface surface to receive said stabilizer and said external threads extending toward said stabilizer interface surface beyond the cross-sectional depth of the stabilizer;
- and
- a nut having a relatively constant diameter through bore having internal threads which cooperate with the threads of said anchor seat which is exterior to said elongated stabilizer and said seat and said screw means cooperating to allow relative limited motion whereby alignment of the means to receive the stabilizer is facilitated and transfer of load from the stabilizer to the interface of the spine and the screw is inhibited.
A fixation device for the posterior stabilization of one or more bone segments of the spine, comprising:
- at least two anchors and an elongated stabilizer comprising a rod having a diameter and a longitudinal axis, said anchors each comprising anchoring means which secure said anchors to said bone segment and an anchor seat means which has a lower bone interface operatively joined to said bone segment and an anchor seat portion spaced apart from said bone interface including a channel to receive said rod;
- and
- securing means which cooperate with each of said anchor seat portions spaced apart from said bone interface and exterior to the bone relative to said elongated rod, said seat means including a vertical axis and first threads which extend in the direction of said vertical axis toward said lower bone interface to a depth below the diameter of the rod when it is in the rod receiving channel, and said securing means including second threads which cooperate with the first threads of the seat means to cause said rod to bear against said channel through the application of substantially equal compressive forces by said securing means in the direction of the vertical axis and applied on either side along said longitudinal axis of said channel.
A device for the stabilization of one or more bone segments, comprising:
- at least two anchors and a rod having a diameter, said anchors each comprising screw means, an anchor seat, and a nut, said anchor seat including external threads and a channel to receive said rod and having a rod contacting surface in the bottom of the channel and said threads extending toward the rod contacting surface to a thread run-out, the distance between the rod contacting surface and the thread run-out being less than the diameter of the rod;
- and said nut including top and bottom surfaces and a relatively constant diameter through bore having threads which mate with the threads of the anchor seat and said nut being exterior to said rod and tightening down toward the rod whereby said bottom surface applies a compressive force to said rod.
Dependencies are inferred from the claim text.