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US 8,998,966 B2Granted
Polyaxial facet fixation screw system with fixation augmentation
AssigneeOsteoMed LLC
InventorsMarc Yap, Rob D. Dickerman, Matthew T. Bennett, Charles R. Forton, Andrew R. Fauth, Joel R. Helgerson, Shresta Marigowda
Life of this patent
Estimating the term…
Abstract
A screw system includes a screw and a washer assembly captive to the screw. The washer assembly is polyaxially pivotable relative to the screw. The screw may be freely rotated in one direction relative to the washer assembly, but frictionally binds with the washer assembly when rotated in a second direction. Various auxiliary fixation features are disclosed.
Claims18
A system, comprising:
- a screw, wherein the screw comprises a spherical head and a shaft extending from the head, wherein the shaft comprises a threaded portion and an auxiliary fixation feature, wherein the threaded portion extends along a distal portion of the shaft,
- wherein the system has an insertion configuration and a deployed configuration, wherein the auxiliary fixation feature is substantially contained within the shaft in the insertion configuration, the auxiliary fixation feature comprising a rod, a pin and at least one prong, wherein the pin and the at least one prong extend distally from a distal end of the rod, wherein in the deployed configuration the at least one prong of the auxiliary fixation feature protrudes beyond the shaft and the pin remains within the shaft, wherein the system is transformable between the insertion configuration and the deployed configuration;
- and
- a washer around the head, wherein the washer comprises a socket, wherein the socket receives the head to form a ball-and-socket joint, wherein the screw is freely rotatable relative to the washer when the head rotates in an insertion direction, wherein the screw and washer become locked together when the head rotates in a removal direction, wherein the removal direction is opposite the insertion direction.
1 more element
A system, comprising:
- a fixation element, wherein the fixation element comprises a screw and a washer, wherein the screw comprises a spherical head and a shaft extending from the head, wherein the shaft comprises a distal threaded portion,
- wherein the washer comprises a socket, wherein the socket receives the head to form a ball-and-socket joint, wherein the screw is freely rotatable relative to the washer when the head rotates in an insertion direction, wherein the screw and washer become locked together when the head rotates in a removal direction thereby locking removal rotation of the screw, wherein the removal direction is opposite the insertion direction;
- and
- an auxiliary fixation element comprising a rod, a pin and at least one prong, wherein the pin and the at least one prong extend distally from a distal end of the rod, wherein the auxiliary fixation element is substantially contained within the fixation element in an insertion configuration, wherein when an axial actuation force is applied, the auxiliary fixation element in a deployed configuration becomes actuated so that the at least one prong protrudes from the fixation element and the pin remains within the fixation element.
1 more element
A bone fastener, comprising:
- a fixation element, wherein the fixation element comprises a screw and a washer, wherein the screw comprises a spherical head and a shaft extending from the head, wherein the shaft comprises a distal threaded portion, wherein the washer comprises a socket, wherein the socket receives the head to form a ball-and-socket joint, wherein the screw is freely rotatable relative to the washer when the head rotates in an insertion direction, wherein the screw and washer, when assembled, become locked together and prevents rotation of the screw in a removal direction, wherein the removal direction is opposite the insertion direction;
- and
- an auxiliary fixation element comprising a rod, a pin and at least one prong, wherein the pin and the at least one prong extend distally from a distal end of the rod, wherein the auxiliary fixation element is substantially contained within the shaft of the fixation element during insertion of the fastener, wherein the auxiliary fixation element provides no resistance to insertion of the fastener, wherein the auxiliary fixation element is actuatable after insertion so that the auxiliary fixation element provides resistance to removal of the fastener, wherein when the auxiliary fixation element is actuated the at least one prong protrudes from the shaft and the pin remains within the shaft.
Dependencies are inferred from the claim text.