Drill guide with angle verification

摘要

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.

主权项

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.