Devices and methods for monoaxial screw conversion
AssigneeDePuy Synthes Products, Inc.
InventorsShawn D. Stad, Frank Spratt, James Paiva
Life of this patent
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Abstract
Devices and methods for selectively converting polyaxial bone screws into monoaxial screws are described herein. In one embodiment, a spinal screw extension instrument is provided having an outer component configured to engage a receiving member of a polyaxial screw. The instrument further includes an inner component disposed within an inner lumen of the outer component and configured to translate longitudinally relative to the outer component such that the inner component can apply a distal force to a compression member of the polyaxial screw disposed within a distal portion of the receiving member to thereby convert the polyaxial screw to a monoaxial screw.
Claims20
A spinal screw extension instrument, comprising:
- an outer component having an inner lumen extending therethrough and a distal end with opposed arms configured to engage a receiving member of a polyaxial screw such that opposed slots formed between the opposed arms are aligned with opposed slots formed in the receiving member;
- and
- an inner component disposed within the inner lumen of the outer component and having a distal end with opposed arms and opposed slots formed between the opposed arms, the inner component being configured to translate longitudinally relative to the outer component such that the opposed slots of the inner component are aligned with the opposed slots of the outer component and the receiving member, the opposed arms of the inner component being configured to apply a distal force to a compression member of the polyaxial screw disposed within a distal portion of the receiving member to thereby convert the polyaxial screw to a monoaxial screw.
A spinal fixation kit, comprising:
- a polyaxial screw having
- a threaded shank having a head formed on a proximal end thereof,
- a receiving member having a spherical seat formed in a distal portion thereof for seating the head formed on the threaded shank, and an aperture extending through a distal end
- thereof to allow the threaded shank to extend distally from the receiving member, and a compression member disposed within the receiving member and having a first position in which the receiving member is polyaxially movable relative to the threaded shank, and a second position in which the compression member engages the head formed on the threaded shank to lock the threaded shank in a fixed position relative to the receiving member and thereby convert the polyaxial screw into a monoaxial screw;
- and
- a screw extension instrument having
- an outer component with a distal end configured to engage the receiving member such that opposed slots formed in the distal end of the outer component align with opposed slots formed in the receiving member, and
- an inner component coupled to the outer component and configured to longitudinally translate relative to the outer component, the inner component having a distal end with opposed slots that are aligned with the opposed slots of the outer component and the receiving member, the inner component being configured to advance distally to apply a distal force to the compression member to move the compression member from the first position to the second position.
A method for correcting spinal deformities, comprising:
- coupling a screw extension instrument to a receiving member of a polyaxial screw, the receiving member being coupled to a threaded shank that is polyaxially movable relative to the receiving member;
- and
- advancing an inner component of the screw extension instrument relative to the receiving member of the polyaxial screw to cause the inner component to convert the polyaxial screw into a monoaxial screw.
Dependencies are inferred from the claim text.