Locking Element for a Polyaxial Bone Anchor, Bone Plate Assembly and Tool
AssigneeMiami Device Solutions, LLC
InventorMarkku Biedermann
Life of this patent
Estimating the term…
Abstract
A locking element is configured to be used with a polyaxial bone anchor, and is substantially cylindrical with a bottom side facing a head of the bone anchor, a top side opposite to the bottom side, and a surface portion with an external thread. The locking element has a first recess at the bottom side for accommodating at least a portion of the head, and a second recess at the top side for engagement with a driver. The second recess is located outside the center of the top side. The head has a portion with a largest diameter, and a first level L1 is defined by the highest point of a circle with the largest diameter drawn around the head, and a second level L2 is defined by the bottom of the second recess, L2 being at a level not higher than L1.
Claims41
A locking element configured to be used with a polyaxial bone anchor, the locking element being substantially cylindrical with a bottom side facing a head of the bone anchor, a top side opposite to the bottom side, and a surface portion with an external thread;
- wherein, the locking element has a first recess at the bottom side for accommodating at least a portion of the head, and a second recess at the top side for engagement with a driver, the second recess being located outside the center of the top side, and
- wherein the head has a portion with a largest diameter (d), and a first level L1 is defined by the highest point of a circle with the largest diameter drawn around the head, and a second level L2 is defined by the bottom of the second recess, L2 being at a level not higher than L1.
A bone plate assembly, comprising:
- an elongate plate member with a top side and a bottom side,
- at least two holes extending from the top side to the bottom side,
- at least two bone anchors, each bone anchor comprising a shank configured to anchor into the bone, and a head having a portion with a largest outer diameter (d), wherein the shank is extendable through the hole;
- wherein at least one of the holes is configured to define a seat at the bottom side adapted to pivotably receive the head, and wherein the at least one of the holes includes a bore at the top side with a bore axis and an inner diameter (D) at least as large as the largest diameter (d) of the head;
- and
- a locking element configured to be inserted into the bore, having a central axis coaxial with the bore axis, a bottom side facing the head, and a top side facing away from the head;
- wherein the locking element has a first recess at the bottom side for at least partially covering the head, and a second recess at the top side for engagement with a driver, the second recess being located outside the center of the top side;
- wherein the highest point of a circle with the largest diameter (d) that is drawn around the head defines a first level L1 and the bottom of the second recess defines a second level L2, which is at a level not higher than L1.
A bone plate assembly, comprising:
- an elongate plate member with a top side and a bottom side,
- at least two holes extending from the top side to the bottom side,
- at least two bone anchors, each bone anchor comprising a shank configured to anchor into the bone, and a head having a top and a portion with a largest outer diameter (d), wherein the shank is extendable through the hole;
- wherein at least one of the holes is configured to define a seat at the bottom side adapted to pivotably receive the head and wherein the at least one of the holes includes a bore at the top side with a bore axis and an inner diameter (D) which is at least as large as the largest diameter (d) of the head;
- and
- a locking element configured to be inserted into the bore and having a central axis coaxial with the bore axis, a bottom side facing the head, a top side facing away from the head and a recess at the top side configured to be engaged with a driver, the recess being located outside the center of the top side and having a depth that extends below the top of the screw head when the screw head is in the seat.
A tool adapted for use with a bone plate assembly, comprising:
- a driver with an engagement portion configured to engage a locking element;
- and
- a tubular holder;
- wherein the driver is configured to extend with the engagement portion through the tubular holder,
- wherein the driver is axially movable and rotatable within the holder, and
- wherein the holder has a radial slot adapted for insertion of the locking element, and
- wherein, the bone plate assembly comprises
- an elongate plate member with a top side and a bottom side,
- at least two holes extending from the top side to the bottom side,
- at least two bone anchors, each bone anchor comprising a shank configured to anchor into the bone, and a head having a top and a portion with a largest outer diameter (d), wherein the shank is extendable through the hole;
- wherein at least one of the holes is configured to define a seat at the bottom side adapted to pivotably receive the head and wherein the at least one of the holes includes a bore at the top side with a bore axis and an inner diameter (D) which is at least as large as the largest diameter (d) of the head;
- and
- a locking element configured to be inserted into the bore and having a central axis coaxial with the bore axis, a bottom side facing the head, a top side facing away from the head and a recess at the top side configured to be engaged with a driver, the recess being located outside the center of the top side and having a depth that extends below the top of the screw head when the screw head is in the seat.
Dependencies are inferred from the claim text.