Patent ID: 8702761

Claim:
A limited angulation bone screw assembly comprising: a bone screw ( 10 ) comprising: an upper head portion ( 20 ), the upper head portion ( 20 ) being a substantially spherical surface ( 23 ) having one or more flat surfaces ( 18 ) disposed on a side of the upper head portion ( 20 ); and a threaded shaft ( 13 ) assembled to the head portion ( 20 ); a bushing ( 30 ) comprising: an upper portion ( 31 ) having a seat ( 33 ) shaped to receive a spinal rod; a lower portion ( 32 ) having a rounded surface ( 35 ) and one or more flexible flanges ( 43 ) having an inner planar surface ( 46 ) configured to splay when coupled with the spherical surface ( 23 ) and one or more flat surfaces ( 18 ) of the bone screw ( 10 ) to provide a compressive force on the one or more flat surfaces ( 18 ) when the bushing ( 30 ) is coupled to the bone screw ( 10 ); and a housing ( 50 ) comprising: an upper portion ( 53 ) with a first opening ( 67 ) and two spaced apart arms ( 55 ), each arm comprising internal threads ( 61 ), and a U-shaped channel ( 74 ) extending along a second axis transverse to a first axis ( 63 ) adapted to receive the spinal rod; a lower portion ( 56 ) with a second opening ( 69 ) being sized to engage the upper head portion ( 20 ) of the bone screw ( 10 ); and the first axis ( 63 ) extending between the upper and lower portions; and; wherein the coupled screw ( 10 ) and bushing ( 30 ) are insertable through the first opening ( 67 ) until the threaded shaft ( 13 ) extends through the second opening ( 69 ) and the upper head portion ( 20 ) engages the second opening ( 69 ); and wherein the coupled screw ( 10 ) and bushing ( 30 ) within the housing ( 50 ) restrict angulation motion of the threaded shaft ( 13 ) of the bone screw ( 10 ) to a single plane including the first and second axis.