Non-locking multi-axial joints in a vertebral implant and methods of use
A connector pivotally connects an anchor to a longitudinal member in a spinal implant. The connector body may include an oppositely disposed channel and cavity that are aligned on a common axis of the body, but isolated from each other. The channel receives the longitudinal member and the cavity receives the anchor. The anchor may include a shaft and an enlarged head that fits within the cavity. The cavity may include a narrow opening that is sized to retain the head within the cavity. The head may pivot within a wear member. The anchor may freely pivot within the cavity when a fastener mates with the receiver to maintain the longitudinal member within the channel.
1 . A connector to connect a vertebral member to a longitudinal member, the connector comprising:
an anchor comprising a shaft and an enlarged head;
a body attached to the anchor and comprising a receiver and a cavity that are aligned along a common axis, the receiver comprising a channel sized to receive the longitudinal member; and
a fastener configured to mate with the receiver to maintain the longitudinal member in the channel, a force applied by the fastener to maintain the longitudinal rod within the channel being isolated from the anchor; and
the cavity positioned on an opposite side of the body from the receiver and the cavity comprising a narrow opening that extends into an enlarged receiving area, the receiving area being isolated from the channel and sized to pivotally accommodate the head of the anchor with the narrow opening sized to retain the head within the receiving area.
2 . The connector of claim 1 , wherein the anchor is movably positioned within the body to pivot about the common axis.
3 . The connector of claim 1 , wherein the body further comprises an intermediate section positioned between the channel and the receiving area, the intermediate section and the body being constructed from a single member.
4 . The connector of claim 3 , wherein the intermediate section has a thickness to space apart the channel and the receiving area.
5 . The connector of claim 1 , wherein the receiving area further comprises a wear member that contacts the head of the anchor, the wear member being constructed of a different material from the body.
6 . The connector of claim 5 , wherein the wear member has an outer surface that contacts the body and an inner surface that contacts the head of the anchor.
7 . The connector of claim 5 , wherein the wear member has an outer surface that is constructed of a wear resistant coating.
8 . The connector of claim 1 , wherein a top section of the receiving area has a rounded configuration to conform with the head of the anchor.
9 . The connector of claim 1 , wherein the head of the anchor is constructed with a wear resistant coating.
10 . A connector to connect a vertebral member to a longitudinal member, the connector comprising:
an anchor comprising a shaft and an enlarged head;
a body attached to the anchor and comprising a channel and a cavity aligned along a common axis, the channel sized to receive the longitudinal member;
a fastener configured to maintain the longitudinal member in the channel, a force applied by the fastener to maintain the longitudinal member within the channel being isolated from the anchor; and
a wear member positioned within the cavity and constructed from a material different from the body, the wear member forming a receiving area sized to pivotally accommodate the head of the anchor;
the cavity comprising a narrow opening to retain the head within the receiving area and the receiving area positioned for the anchor to pivot when the fastener maintains the longitudinal member in the channel.
11 . The connector of claim 10 , wherein the head contacts the wear member when the anchor pivots within the body.
12 . The connector of claim 10 , wherein the wear member is a coating applied to an inner surface of the cavity.
13 . The connector of claim 10 , wherein the wear member comprises a first surface that contacts an inner surface of the cavity, and a second surface that contacts the head of the anchor.
14 . The connector of claim 10 , wherein an adhesive attaches the wear member to an inner surface of the cavity.
15 . The connector of claim 10 , wherein the wear member has a width that is greater than the narrow opening to maintain the wear member within the cavity.
16 . The connector of claim 10 , wherein the anchor is movably positioned within the wear member to pivot about the common axis.
17 . The connector of claim 10 , wherein the body further comprises an intermediate section positioned between the channel and the cavity, the intermediate section and the body being constructed from a single member.
18 . The connector of claim 10 , wherein a top section of the cavity comprises a stop to prevent the wear member from pivoting within the cavity during movement of the anchor.
19 . The connector of claim 10 , wherein the head of the anchor is constructed with a wear resistant coating.
20 . The connector of claim 10 , wherein the wear member is constructed with a wear resistant coating.
21 . A connector to connect a vertebral member to a longitudinal member, the connector comprising:
an anchor comprising a shaft and an enlarged head;
a body attached to the anchor and being constructed from a single member having a receiver, a cavity, and an intermediate section, the receiver comprising a channel sized to receive the longitudinal member; and
a fastener configured to mate with the receiver to maintain the longitudinal member in the channel;
the cavity and channel being aligned on a common axis and positioned on opposite sides of the intermediate section, the cavity comprising a narrow opening that extends into an enlarged receiving area, the receiving area being isolated from the channel and sized to accommodate the head of the anchor, and the narrow opening being sized to retain the head within the receiving area;
the receiving area being isolated from the channel and sized to allow the anchor to freely pivot when the fastener mates with the receiver.
22 . The connector of claim 21 , wherein the intermediate section is substantially perpendicular to the common axis.
23 . The connector of claim 21 , further comprising a wear member positioned within the receiving area to contact the head of the anchor, the wear member constructed of a different material than the body.
24 . The connector of claim 23 , wherein the different material comprises a wear resistant coating.
25 . The connector of claim 21 , wherein the anchor is movably positioned within the body to pivot about the common axis.
26 . The connector of claim 21 , wherein a top section of the receiving area has a rounded configuration to conform with the head of the anchor.
27 . The connector of claim 21 , wherein the head of the anchor is constructed with a wear resistant coating.