PEDICLE SCREW WITH EXPANSION ANCHOR SLEEVE

• US 20100324607A1
• Filed: 06/23/2010
• Published: 12/23/2010
• Est. Priority Date: 06/23/2009
• Status: Abandoned Application

• Current Assignee: Reginald J. Davis
• Original Assignee: Reginald J. Davis
• Inventors: Davis, Reginald J.
• Application Number:
  US12/821,945
• Publication Number:
  US 20100324607A1
• Time in Patent Office: Days
• US Class Current: 606/313
• CPC Class Codes: A61B 17/7032 Screws or hooks with U-shaped head or back through which longitudinal rods pass
• CPC Class Codes: A61B 17/8625 Shanks, i.e. parts contacting bone tissue
• CPC Class Codes: A61B 17/864 hollow, e.g. with socket or cannulated
• CPC Class Codes: A61B 17/8685 comprising multiple separate parts

Abstract

A bone anchor for use in conjunction with orthopedic spinal fixation comprising a pedicle screw having a threaded proximal tip for threaded insertion into a hole prepared into a vertebral body through the pedicle of the vertebra from the posterior approach. The shank of the anchor is of smaller diameter than the proximal tip so as to receive a sleeve after insertion into the bone. The tubular sleeve is provided with a plurality of longitudinal slots evenly arranged about the longitudinal axis of the sleeve to forming a plurality of longitudinal. A tubular compression collar for insertion over said shank portion is provided on the shank and driven toward the proximal tip compression the sleeve and causing the ribs to expand radially into a star pattern securing the anchor in the bone. A tubular collar of natural or synthetic bone growth promoting material may be inserted to promote bone growth, close the hole and further stabilize the anchor. An elastomeric collar may also be inserted over the shank and extend beyond the end of the shank to flexibly receive a rod seat for receiving an orthopedic rod affixed to said elastomeric collar.

Claims

1. A bone anchor comprising

a screw having a shank portion and proximal portion, the proximal portion having a diameter greater than the shank portion, said proximal portion characterized by external threads for engagement with a hole prepared in a bone;

a tubular sleeve having a first end and a second end and sized for insertion over said shank portion of the said screw wherein said first end is engaged with said proximal portion, said sleeve having a plurality of longitudinal slots arranged about the longitudinal axis of said sleeve thereby forming a plurality of longitudinal ribs there between;

a tubular collar for insertion over said shank portion wherein said collar is engaged with said second end of said sleeve.

2. The bone anchor of claim 1 further comprising

a tubular collar of natural or synthetic bone growth promoting material for insertion over said shank portion wherein said bone growth promoting material collar is advanced down said shank so as to contact said bone;

an elastomeric collar for insertion over said shank portion, said elastomeric extending beyond the distal end of said shank portion; and

a rod seat for receiving an orthopedic rod affixed to said elastomeric collar.

3. A method of securing a bone anchor to a bone comprising the steps of:

providing a pre-drilled hole in a bone;

inserting into said hole a bone screw having a shank portion and proximal portion, the proximal portion having a diameter greater than the shank portion, said proximal portion characterized by external threads, said thread engaging the surface of said bone within said hole so as to advance said proximal portion of said screw into said hole on rotation of said shank portion;

inserting a tubular sleeve having a first end and a second end over said shank portion of the said screw and into said hole wherein said first end is engaged with said proximal portion of said bone screw, said sleeve having a plurality of longitudinal slots arranged about the longitudinal axis of said sleeve thereby forming a plurality of longitudinal ribs there between;

inserting a compression collar over said shank portion of the said screw and into said hole wherein said compression collar is engaged with said second end of said sleeve;

driving said compression collar down said shank toward said proximal end thereby compressing said sleeve and causing said ribs form a radial pattern of arms substantially perpendicular to said longitudinal axis, said pattern having a diameter greater than the diameter of said hole.

4. The method of claim 3 further comprising inserting over said shank portion a collar of natural or synthetic bone growth promoting material, said bone growth promoting material collar being advanced down said shank so as to contact said bone.

5. The method of claim 3 further comprising inserting over said shank portion an elastomeric collar, said elastomeric extending beyond the distal end of said shank portion.

6. The method of claim 5 further comprising inserting a rod seat on to said elastomeric collar for receiving an orthopedic rod.