Drill guide with angle verification

Patent metadata

Field	Value
Publication number	US-8936600-B2
Application number	US-201213722358-A
Country	US
Kind code	B2
Filing date	Dec 20, 2012
Priority date	Dec 23, 2008
Publication date	Jan 20, 2015
Grant date	Jan 20, 2015

Abstract

A method and instrument is used for inserting a bone screw through a hole in a bone plate into bone at a maximum angulation of a bone screw central longitudinal axis with respect to a central axis of the hole. The maximum angulation places the head of the bone screw at or below an outwardly facing surface of the bone plate. The instrument has a distal end including a gauge element spaced proximally from an end surface of the distal end when in contact with a counterbore surrounding the plate hole a distance less than a depth of the counterbore. The instrument is tilted with respect to a central axis of the bone plate hole to an angle wherein the gauge element remains at or below the outwardly facing surface of the bone plate adjacent the counterbore. A hole is drilled through a guide bore in the instrument.

First claim

The invention claimed is:

1. A method for inserting a bone screw through a hole in a bone plate and into bone at a maximum angulation of a bone screw central longitudinal axis with respect to a central axis of the hole, comprising:
placing a bone contacting surface of a bone plate on a bone surface, the bone plate having at least one screw hole surrounded by a recessed part-spherical surface formed in an outermost surface of the bone plate opposite the bone contacting surface;
the screw hole extending from a base of the recessed part-spherical surface to the bone contacting surface along a central axis;
inserting an instrument having a distal portion into the recessed part-spherical surface surrounding the plate hole, the instrument distal portion including a guide bore extending along an axis, a circumferentially extending gauge element, the gauge element spaced proximally from a distal most surface of the instrument distal portion, where the distal most surface contacts a base of the recessed part-spherical surface, the spacing of the gauge element from the distal most surface of the instrument is less than or equal to a distance from the base of the recessed part-spherical surface to the outermost surface of the bone plate so that the gauge element is at or below the plate outermost surface when the gauge element guide bore axis is rotated up to 10° from a coaxial position with respect to the central hole axis;
tilting the inserted instrument about the central axis of the bone plate hole to the angle of up to 10° wherein the gauge element remains at or below an outermost surface of the bone plate which is adjacent the recessed part-spherical surface;
drilling a hole in the bone through the guide bore in the instrument; and
inserting a bone screw into the bone plate screw hole.

2. The method as set forth in claim 1 wherein the gauge element is an indicator extending around a circumference of the instrument distal portion.

3. The method as set forth in claim 2 further comprising tilting the instrument to a maximum angle that maintains the circumferential indicator at or below the outermost surface of the bone plate surrounding the recessed part-spherical surface.

4. The method as set forth in claim 3 wherein the maximum angle of instrument tilt which maintains the circumferential indicator below the outer surface of the bone plate is 10°.

5. The method as set forth in claim 3 wherein the maximum angle of tilt is 10°.

6. The method as set forth in claim 4 wherein the instrument is tilted by manipulating a handle attached to the distal portion of the instrument.

7. The method as set forth in claim 1 wherein the distal portion of the instrument has a distal most surface which is part-spherical in shape.

8. The method as set forth in claim 2 wherein the indicator extends around the entire circumference of the distal portion of the instrument.

9. The method as set forth in claim 8 wherein the guide bore in the distal portion of the instrument extends perpendicular to a plane containing the entire circumference of the indicator.

10. The instrument as set forth in claim 3 wherein the circumferential indicator is formed entirely around a cylindrical portion of the instrument distal portion, the cylindrical portion having a diameter equal to a maximum diameter of the distal portion part-spherical section.

11. The method as set forth in claim 1 wherein the recessed part-spherical surface has a concave surface surrounding the at least one screw hole in the bone plate.

12. The method as set forth in claim 11 wherein the instrument distal portion has a leading end including a part-spherical convex surface for contacting the recessed part-spherical concave surface surrounding the at least one screw hole.

13. The method as set forth in claim 12 wherein the instrument distal portion proximal of the leading end is cylindrical, with the cylinder having a diameter equal to the largest diameter of the part-spherical convex surface of leading end.

14. A method for inserting a bone screw through a bore in a bone plate and into a bone at a maximum angulation of a bone screw central longitudinal axis with respect to a central axis of the hole, comprising:
obtaining a bone screw having a head and a shaft;
placing a bone plate on a bone surface, the bone plate having at least one bore surrounded by a recessed part-spherical surface, the bone plate having a bone contacting surface and an outwardly facing surface spaced therefrom;
placing a drill guide having a guide bore extending along an axis and having a distal portion with a curved contact surface formed on a distal end thereof on the recessed part-spherical surface of the bone plate, the drill guide distal portion having a circumferential marking extending around a cylindrical surface of the distal portion, the bone screw head having a height corresponding to the marking, the circumferential marking spaced from a distal most surface of the drill guide distal portion a distance less than the distance from a surface of the recessed part-spherical surface closest to the bone-contacting surface to the outermost bone plate surface so that pivoting the drill guide bore axis with respect to the central axis of the hole to a predetermined angle locates the marking at or below the outermost surface of the bone plate;
tilting the drill guide bore axis with respect to the central axis of the bone plate hole to the predetermined angle so that the circumferential marking is at or below the outermost outwardly facing surface of the bone plate;
drilling a hole in the bone through a bore in the drill guide; and
inserting a bone screw into the bone plate hole at the predetermined angle so the bone screw head contacts the recessed part-spherical surface.

15. The method as set forth in claim 14 wherein the maximum angle of tilt is 10°.

Assignees

• Howmedica Osteonics Corp

Inventors

• Soliman Mohamed

Classifications

• A61B17/1739

  specially adapted for particular parts of the body · CPC title

• A61B2019/467

  Human Necessities · mapped topic

• A61B17/1728 Primary

  for holes for bone plates or plate screws · CPC title

• A61B2090/067

  for measuring angles · CPC title