System for reducing the displacement of a vertebra

An assembly for reducing a displaced vertebra and connecting the displaced vertebra to a spinal implant rod, comprising:

• a reduction bolt, said reduction bolt having machine threads on a proximal portion and coarse threads on a distal portion;
• a connection unit, said connection unit having a rod connecting portion with an opening for receiving a portion of the rod, and a bolt connecting portion having an opening for receiving a portion of said reduction bolt and for permitting translational movement of said connection unit over said reduction bolt;
• at least one interface washer positioned over and between the rod connecting portion and the bolt connecting portion, said interface washer being moveable in part between the rod connecting portion and the bolt connecting portion, said interface washer having a lateral edge;
• a nut, said nut operatively engaging the machine threads of said reduction bolt;
• a collar, said collar having an opening for receiving a portion of said reduction bolt and for permitting translational movement of said collar over said reduction bolt;
• said collar having a posterior face, said collar having a notch in the posterior face for receiving a portion of the lateral edge of said interface washer, the notch partly defining the opening in the posterior face of said collar to pass said reduction bolt, said collar positioned on said reduction bolt, between said nut and said connection unit.

An apparatus for use in reducing a displaced vertebra, comprising:

• a longitudinal member positionable along the longitudinal axis of the spine;
• a first vertebral anchor and a second vertebral anchor;
• a first clamp, a second clamp, and a third clamp, said first clamp fixedly securing said first vertebral anchor to said longitudinal member, said second clamp fixedly securing said second vertebral anchor to said longitudinal member, said third clamp having a longitudinal member connecting portion with an opening for receiving a portion of the longitudinal member, and a bolt connecting portion having an opening for receiving a portion of a reduction bolt and for permitting translational movement of said third clamp over a reduction bolt;
• a reduction bolt, said reduction bolt positioned inside the bolt connecting portion of said third clamp, said reduction bolt having machine threads on a proximal portion and coarse threads on a distal portion;
• a bolt interface washer, said bolt interface washer positioned over and between the longitudinal member connecting portion and the bolt connecting portion of said third clamp, said interface washer being moveable in part between the longitudinal connecting portion and the bolt connecting portion, said bolt interface washer having a lateral edge;
• a nut, said nut threadably engaged to the machine threads on the proximal portion of said bolt;
• a clamp interface collar, said clamp interface collar having an opening for receiving a portion of said reduction bolt and for permitting translational movement of said collar over said reduction bolt;
• said clamp interface collar having a notch therein for receiving a portion of the lateral edge of said bolt interface washer, said clamp interface collar positioned on said reduction bolt, between said nut and said third clamp;
• whereby said nut can be tightened against said clamp interface collar to pull said reduction bolt and thereby move a displaced vertebra toward the longitudinal member, said third clamp can be tightened to fixedly secure said reduction bolt to said longitudinal member, and said nut and said clamp interface collar can be removed from the patient without the vertebra moving away from said longitudinal member.

A method for aligning a displaced vertebra, comprising the steps of:

• attaching a bone bolt to a displaced vertebra, said bone bolt having coarse threads to engage the vertebra on one portion of the bolt and machine threads on a second portion of the bone bolt;
• positioning a spinal rod along the longitudinal axis of the spine;
• positioning a clamping device on the bone bolt and the spinal rod, said clamping device having a compression member that, when engaged, simultaneously tightens the bone bolt and the spinal rod to the clamping device;
• sliding a collar over the bone bolt and allowing the collar to rest against the clamping device;
• threading a nut over the machine threads on the bone bolt and against the collar and thereby pull the bone bolt through the collar and the clamping device and move the displaced vertebra toward the spinal rod;
• tightening the compression member on the clamping device to hold the bone bolt and the spinal rod;
• and
• removing the nut and collar from the bone bolt.