| abstract |
A facet screw system for surgical implantation into bone tissue having a shaft, a compression member and a washer. The shaft includes a shaft having a bone engaging portion and a compression member engaging portion. The compression member includes a spherical head portion having a recess for engaging with a driving instrument, and an elongated coupling portion having internal threads for coupling with the compression member engaging portion of the shaft and a washer coupled to the spherical head portion of the compression member and having a plurality of bone engaging protrusions. The washer is adapted to be polyaxially rotatable with respect to the compression member. |