Fixation screw assembly

摘要

An orthopedic device has a configuration that employs a scalloped profile that defines internal scalloped edges having troughs and crests that extend substantially along the outer edge of a head of the device. The troughs and crests interface with a series of troughs and crests around the openings in the device. Each of the openings includes an outwardly extending slot that permits the opening to expand and contract outward as the head of the anchor is rotated. This enables an anti-backout feature that prevents or substantially inhibits undesired rotation and backout.

主权项

1. A bone stabilizer assembly, comprising:
i. a fixation member configured to engage a bone and having a head portion and a shank portion; ii. a coupling member having proximal and distal ends and comprising:
a. two upwardly extending projections that are opposed to each other and separated by an internal bore sized to receive the shank portion of the fixation member, the two upwardly extending projections each having a deflectable threading on an internal surface;b. a seat configured to support the head portion of the fixation member; andc. a locking member first portion comprising a first plurality of detents positioned proximally to the deflectable threading on the internal surface of each of the upwardly extending projections; and iii. a compression nut comprising:
a. a compression nut threading positioned on a surface of the compression nut to threadably engage the deflectable threading on the internal surface of each of the two upwardly extending projections when the compression nut engages with the coupling member; andb. a locking member second portion comprising a second plurality of detents; wherein the coupling member and the compression nut are configured to engage each other via the locking member first and second portions in a first and a second configuration when the coupling member and compression nut are coupled with each other, wherein in the first configuration, protrusions of the second plurality of detents engage recesses of the first plurality of detents to limit rotation of the compression nut within the coupling member, and wherein in the second configuration, the protrusions of the second plurality of detents engage protrusions of the first plurality of detents causing the upwardly extending projections to splay and increase a diameter of the bore at the proximal end of the coupling member, and wherein splaying at the proximal end of the coupling member causes the deflectable threading to deflect; and wherein when the coupling member and the compression nut are coupled, the deflectable threading is positioned relative to the compression nut threading so that when the deflectable threading deflects in the second configuration, it deflects in a proximal direction and engages with a recess in the threading of the compression nut thereby resisting splaying towards the distal end of the coupling member.