| 摘要 |
A polyaxial orthopedic device for use with rod implant apparatus includes a screw having a curvate head, a locking collar disposed therearound, and a coupling element having a tapered socket into which both the screw and the collar are securely nested. The locking collar is slotted and tapered, and has a semi-spherical interior volume into which the screw head is initially polyaxially held. The coupling element has an axial bore through which the screw and locking collar may be inserted, and a tapered bottom which provides a radially inward force on the locking collar when forces thereinto. This radially inward force causes the locking collar to crush lock against the head of the screw, therein locking the two at the instant angulation. In an initial disposition, however, the screw head remains polyaxially free with respect to the locking collar, and with the coupling element. The coupling element includes a transverse channel in which a rod may be disposed. In a first embodiment the channel is formed between a pair of upwardly extending members, and in a second embodiment, the channel is formed in the side of the element. In either case, a rod which is inserted in the channel, seats against the top of the locking ring.
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