US 8,298,274 B2 · Multi-axial bone screw assembly

Abstract

A bottom-loading multi-axial bone anchor apparatus is disclosed. The apparatus includes a receiver member, a crown member, a bone anchor and a retaining member. The receiver member defines an upper opening and a lower opening, which may form part of the same opening, a channel, and a groove. The crown member and bone anchor are loaded into the lower opening of the receiver member, and the retaining member fits around the bone anchor and into the groove in the receiver member. The bone anchor is capable of multi-axial positioning with respect to the receiver member. An elongated member is placed in the channel of the receiver member, contacting the crown member, and a compression member is applied via the upper opening. The compression member presses down on the elongated member, which presses down on the crown member and locks the bone anchor between the crown member and the retaining member.

Claims30

Dependent claims

A bone anchor assembly for engagement to an elongated member, comprising:

a bone anchor including a head portion and a bone engaging portion;
and a receiver including a top end, an opposite bottom end, an opening extending through said receiver from said top end to said bottom end, and a channel configured to receive the elongated member and arranged transverse to and communicating with said opening, said receiver including a retaining member occupying a groove in said receiver proximate said bottom end, said retaining member defining an aperture extending therethrough and an engagement surface surrounding a substantial portion of said aperture and configured to engage said head portion of said bone anchor, said engagement surface interrupted by a gap, said gap communicating with said aperture;
and wherein said head portion of said bone anchor is engaged with said engagement surface to thereby permit multi-axial movement of said bone anchor relative to said receiver, and said aperture is sized smaller than said head portion to retain said head portion within said receiver.

A bone anchor assembly for engagement to an elongated member, comprising:

a bone anchor including a head portion and a bone engaging portion;
and a receiver including a top end, an opposite bottom end, an upper opening portion, a lower opening portion, and a channel configured to receive the elongated member and arranged transverse to and communicating with said upper opening portion, said receiver including a retaining member occupying a groove in said lower opening portion proximate said bottom end, said retaining member defining an aperture extending therethrough and an engagement surface surrounding a substantial portion of said aperture and configured to engage said head portion of said bone anchor, said engagement surface interrupted by a gap, said gap communicating with said aperture;
and wherein said head portion of said bone anchor is engaged with said engagement surface to thereby permit multi-axial movement of said bone anchor relative to said receiver, and said aperture is sized smaller than said head portion to retain said head portion within said receiver.

Dependencies are inferred from the claim text.

Multi-axial bone screw assembly

Life of this patent

Multi-axial bone screw assembly

Life of this patent

Abstract

Claims30