Closure for open headed implant

1 . In a plug closure for operably closing a top of a channel between two arms of an open headed medical implant, the improvement comprising:

a) said closure having a radially outer surface that is threaded and at least a pair of openings (or apertures) each being positioned in spaced relationship to both a longitudinal axis of said closure and to a periphery of said closure; said openings being substantially parallel to said axis and being accessible from a top and a bottom of said closure; and

b) a break-off head attached to the top of said closure and operably blocking axial access to said openings such that a removal tool cannot be axially inserted into said openings when said break-off head is attached to said closure; said break-off head being breakable from the closure upon application of a preselected torque to said break-off head, when said closure is positioned between the arms, said break-off head being configured to block axial access to at least a portion of each of said openings such that said openings are positioned so as to be axially inaccessible by the removal tool until said break-off head is broken from said closure.

2 . A closure plug in combination with an open-headed medical implant having a pair of spaced arms with a discontinuous, helically wound interior guide and advancement structure thereon; the plug comprising:

a) a cylindrical body sized and shaped to be received between the arms of the implant and having a central axis; the body having an outer cylindrical surface that has a mating guide and advancement structure thereon that is sized and shaped to rotatably mate with the interior guide and advancement structure of the arms of the implant when the closure is placed between the arms and rotated about the axis;

b) the body having a top surface and a bottom surface; the top surface of the body having at least one opening therein sized and shaped to receive a removal tool; the opening extending parallel to the axis from near the bottom surface to the top surface of the body and opening onto the top surface thereof;

c) the opening being spaced from and positioned between both the axis of the body and the cylindrical surface of the body; and

d) a break-off head breakably and axially joined to the body and adapted to receive an installation tool for operably rotating the body; the head being joined to the body by a torque limiting region that causes the head to break from the body, when a preselected torque is applied to the head; the break-off head being free of pass through openings that align with the body opening so as to operably block axial access to the body opening from above the break-off head by the removal tool until the break-off head breaks from the body and so as to allow access to the body opening when the break-off head breaks from the body.

3 . The combination according to claim 2 wherein:

a) there are multiple spaced openings extending into the body from the top surface thereof.

4 . The combination according to claim 2 including:

a) the break-off head is joined to said body by a neck of smaller diameter than the body and the break-off head; the neck being aligned with the central axis of the body.

5 . The combination according to claim 4 wherein:

a) the body includes at least a pair of the openings in the top thereof; and

b) the neck is positioned between the openings.

6 . The combination according to claim 2 wherein:

a) the interior guide and advancement structure and the mating guide and advancement structure are respective mating discontinuous helical wound threads on bone screw arms of the implant and mating helical wound threads on the closure plug body.

7 . The combination according to claim 2 wherein:

a) the opening is a cylindrical bore and the body top surface includes three such bores sized and shaped to be adapted to receive the removal tool located therein; each of the bores being located at a common radius from the body axis and being spaced at 120° from adjacent tool receiving bores.

8 . The combination according to claim 2 including:

a) the body has multiple openings a tool having a grippable handle and an engagement face; the face including a post extending parallel to an axis of rotation of said tool for each of the body openings;,each said posts being sized, aligned and positioned to simultaneously enter a respective opening so as to rotate and apply torque to the body when said tool is rotated about the axis thereof, whereby the tool is operable to at least remove the body from an implant in which said body has been inserted.

9 . In a closure for operably closing a top of a channel between two arms of an open headed medical implant, the improvement comprising:

a) said closure having at least a pair of apertures each being positioned in spaced relationship to both an axis of said closure and to a periphery of said closure; said apertures being parallel to said axis and being accessible from a top of said closure after installation thereof; and

b) a break-off head attached to the top of said closure and breakable therefrom upon application of a preselected torque to said break-off head; when said closure is positioned between the arms, said apertures being positioned so as to be inaccessible by a tool until said break-off head is broken from said closure.

10 . A closure for an open headed medical implant that has a pair of spaced arms with interior guide and advancement structure thereon; said closure comprising:

a) a closure body that is generally cylindrical with a radially outer surface and having a central axis of rotation; said outer surface having mating guide and advancement structure thereon that is sized and shaped to be matingly received between the implant arms;

b) a pair of apertures in a top surface of said closure that are spaced radially outward from said axis of rotation and each other and that are inward from a periphery of said top surface.