| 摘要 |
A hook device for use with support rod implantation apparatus, having a rod receiving body polyaxially mounted to a blade portion such that the body may be polyaxially manuevered relative to the blade, for easy rod coupling. The blade portion has a semi-spherical head portion which sits above the lamina. The rod receiving portion is a separate coupling element having lower and upper portions. The lower portion is slotted and tapered, and has a semi-spherical interior chamber in which the semi-spherical head is initially polyaxially disposed. The upper portion has a pair of upwardly extending members, defining therebetween a channel for receiving the rod. The uppermost parts of the upwardly extending members include an threading for receiving a top locking nut. A locking ring is disposed about the coupling element, substantially below the side recess; the top of the coupling element being initially positioned above the lower ledge of the side recess such that the rod, when initially disposed therein, seats against the top surface of the locking ring. When the rod is in place, the top locking nut is tightened to provides a downward force onto the rod. The rod, in turn, applies a force against the locking ring to descend down the tapered lower portion, therein locking the semi-spherical head in the interior chamber of the coupling element, and locking it into position relative to the blade portion. In an alternative variation, a rod retaining sleeve may be provided between the locking ring and the nut.
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