A system for flexibly stabilizing a vertebral motion segment by connecting a first vertebra and a second vertebra is disclosed. The system includes an elongate connection element with end portions interconnected by a flexible coupling member. The system includes first and second attachment portions for connecting the connection element to the vertebrae. A first resilient member is positioned between the first end portion and the first attachment portion, and a second resilient member is positioned between the first attachment portion and the second attachment portion. The system is designed such that the second resilient member is compressed when the first and second attachment portions move towards each other, and the first resilient member is compressed when the first and second attachment portions extend away from each other.

A medical device can include a first anchor for attachment to a first bone fragment and a second anchor for attachment to a second bone fragment. The second anchor attachment can be coupled to the first anchor via a compression element between the first anchor and the second anchor. The medical device can include a resorbable element maintaining the first anchor and the second anchor at a first distance. The resorbable element can be configured to at least partially resorb after insertion into a patient. After the resorbable element is at least partially sorbed, the compression element forces the first anchor and/or the second anchor to translate such that the first anchor and the second anchor are at a second distance, thereby compressing the first bone fragment and the second bone fragment.

A receiver assembly for capturing an elongate rod in a receiver of a bone anchor includes the receiver, a first threaded closure, and a second threaded closure. The receiver includes an upper portion that defines a first channel, interior surfaces that have helically wound thread, and a lower pressure insert that can be positioned within the first channel and has upright arms. Each of the first threaded closure and the second threaded closure have a cylindrical body with an external surface having continuous helically wound thread that can rotatably mate with the helically wound receiver thread. The first threaded closure and the second threaded closure are interchangeable for different locking configurations in the receiver assembly. The first threaded closure has a downward protrusion that can compressively engage the elongate rod. The second threaded closure has a bottom surface that can compressively engage the upright arms of the lower pressure insert.

A pivotal bone anchor assembly includes a shank having a shank head and an anchor portion, and a receiver having a first channel for receiving a rod and an axial bore for receiving the shank head, with the axial bore including a downwardly-facing abutment surface and opposed rotation blocking and alignment structures beneath a helically wound thread. The assembly also includes a pressure insert having a second channel and opposite outwardly-projecting flanges with notches formed therein. The pressure insert is top loaded into a first position within the axial bore with the second channel in a mal-aligned position relative to the first channel, with subsequent rotation of the pressure insert moving the second channel into alignment with the first channel, the opposite outwardly-projecting flanges under the downwardly-facing abutment surface, and the opposed rotation blocking and alignment structures into the notches formed into the opposite outwardly-projecting flanges.

A method of assembling a pivotal bone anchor assembly includes positioning a retaining structure into a central bore of a receiver having a planar seating surface above a lower opening, the retaining structure being operably slidably coupled with the planar seating surface and having a central opening, the receiver including upright arms defining an open channel configured to receive a rod and exterior surfaces comprising opposite cylindrical upper side surfaces defining a first width and opposite lower side surfaces below the upper side surfaces defining a second width. The method also includes positioning a partially spherical head of a shank into the central opening of the retaining structure, with the retaining structure being slidably movable along the planar seating surface of the receiver to provide for increased articulated movement between the shank and the receiver in at least one direction relative to a vertical centerline axis of the receiver prior to locking the assembly with a closure.

A system for flexibly stabilizing a vertebral motion segment of the facet joint by connecting a first vertebra and a second vertebra is disclosed. The system includes an elongate connection element with end portions interconnected by a flexible coupling member. The system includes first and second attachment portions for connecting the connection element to the vertebrae. A first resilient member is positioned between the first end portion and the first attachment portion, and a second resilient member is positioned between the first attachment portion and the second attachment portion.

An implantable growing rod assembly adapted to be secured along a length of a spine for treating deformities of the spine. The assembly includes a housing, a fixed rod extending along a longitudinal axis away from the housing, and an expansion rod extendible from the housing along the longitudinal axis. A driver assembly is fixed to the housing and adapted to translate the expansion rod along the longitudinal axis.

A dynamic longitudinal connecting member assembly includes an anchor member having an integral or otherwise fixed elongate core of circular or non-circular cross-section. The core is pre-tensioned and extends through at least one elastic spacer and at least one outer sleeve. The anchor member and the outer sleeve each attach to at least one bone anchor. In operation, the core is held in tension by the spacer.

A medical implant assembly includes a polyaxial bone anchor having a shank, a receiver, a lower compression insert with planar surfaces for closely receiving an elongate connecting member with planar surfaces and a one-piece closure structure. The connecting member is made from a polymer. The closure structure engages both the connecting member and the insert with the engagement between the closure structure and the insert securely locking the polyaxial mechanism even if the connecting member exhibits creep.

A medical implant assembly having at least two bone attachment structures cooperating with a dynamic longitudinal connecting member, the improvement wherein the connecting member includes: a first end, a transition portion, and a second end; a substantially rod portion extending longitudinally from the first end to the transition portion, and including a longitudinal axis and a substantially rigid core running substantially parallel with the longitudinal axis; a substantially cord portion joined with the rod portion and extending from the transition portion to the second end; and a substantially flexible jacket portion covering the rod and cord portions.