A pivotal bone anchor assembly includes a receiver having a central bore with a seating surface adjacent a bottom opening and a downward-facing surface above the seating surface, and a shank having a head portion positionable within the axial bore. The assembly also includes a compression insert positionable within the central bore above the head portion and having an upper portion with a notch formed therein to define a resiliently compressible structure extending over the notch. When the head portion of the shank and the compression insert are positioned together in the central bore of the receiver, the engagement between the resiliently compressible structure and the downward-facing surface is configured to provide an axially directed resilient biasing force for a pre-lock friction fit of the pivotal bone anchor assembly prior to securing the longitudinal connecting member in the open channel with the closure.

A receiver assembly includes a receiver having a first channel, a through-space with internal recesses beneath a guide and advancement structure, and internal ridges projecting inwardly below the internal recesses. The assembly also includes an insert having a second channel, side structures protruding laterally outward below top surfaces, and opposed lower extensions extending downwardly below the second channel, with the insert being loadable into the through-space with the second channel in non-alignment with the first channel. The insert is the non-threadably rotatable within the through-space to align the second channel with the first channel and to move the side structures into the internal recesses above the internal ridges, with a subsequent forced downward displacement of the insert within the through-space causing the side structures to frictionally engage the internal ridges to inhibit the insert from moving upward within the through-space.

This disclosure discloses a line coupled to a spine of a user at two points such that the line can be movable relative to those two points. The line can be encased by a protective member between those two points. The line can be covered by a compound between those two points. The line can be guided between those two points.

A dynamic fixation medical implant having at least two bone anchors includes a longitudinal connecting member assembly having rigid sleeves for attachment to the bone anchors, at least one spacer engaging the bone anchors and the sleeves, and in some embodiments, an end elastic bumper. A flexible cord is initially slidingly received within the rigid sleeves, the spacer and the bumper. The spacer may include an optional inelastic inner liner, with at least one of the sleeves having an extension slidingly receivable within the liner. Some sleeves include apertures for receiving a closure top portion for locking the cord against the sleeve, or alternatively receiving a closure top that does not extend into the aperture, the slip or grip option provided by the aperture in each sleeve resulting in an overall connector with variable segmental stiffness.

A pivotal bone anchor assembly includes a shank having a head portion and an anchor portion for fixation to the bone of a patient, and a receiver comprising a base defining a lower portion of central bore and a pair of upright arms defining a channel for receiving an elongate rod. The assembly also includes a retaining structure with a central opening configured to capture and pivotally retain and support the head portion of the shank in the retaining structure, and which is slidably movable relative to the receiver so as to provide for increased articulated movement between the shank and the receiver prior to locking the assembly with the elongate rod and a closure. The assembly further includes an insert configured to engage the elongate rod and the head portion of the shank when in use, and to have an overlapping configuration with the retaining structure when the assembly is in the locked configuration.

A pivotal bone anchor assembly includes a receiver comprising a base defining a lower portion of a central bore, a pair of receiver arms extending upward from the base to define a first channel, and a non-threaded curvate tool engagement groove extending horizontally across an outward facing surface of each receiver arm. The assembly also includes a shank comprising an anchor portion and a partially spherical-shaped head configured for positioning into the lower portion of the central bore. The assembly further includes an insert configured for positioning into the central bore above the head of the shank and having a lower body with partially-cylindrical outer surfaces and a pair of insert arms extending upward from the lower body to define a second channel alignable with the first channel and configured to receive the elongate rod, with each of the insert arms having a flared-out upper portion.

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 resorbed, 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.

According to some embodiments, systems and methods of ultrasonic detection of implantable medical device distraction are provided. The system includes a first elongate member and a second elongate member. The first elongate member has a first end that is configured to be attached to a first location on the skeletal system of a subject, a second end, and at least one landmark identifiable using ultrasound. The second elongate member has a first end that is movably coupled to the second end of the first elongate member, a second end configured to be attached to a second location on the skeletal system, and at least one landmark identifiable using ultrasound. Movement of the first elongate member in relation to the second elongate member causes a corresponding movement of the at least one first landmark in relation to the at least one second landmark which can be detected using ultrasound.

A tool set for implanting bone screws in a human spine, followed by the implantation of a rod into the bone screws includes end guide tools having flexible back wall flaps that receive opposite ends of the rod and intermediate guide tools that hold the rod in intermediate locations between the end guide tools. Both the end and intermediate guide tools include an attachment structure for operably connecting the guide tool to a bone screw. The attachment structure includes an undercut and/or recess so as to resist splaying and separation of the guide tool from an attached bone screw.

A tool set for implanting bone screws in a human spine, followed by the implantation of a rod into the bone screws includes end guide tools having flexible back wall flaps that receive opposite ends of the rod and intermediate guide tools that hold the rod in intermediate locations between the end guide tools. Both the end and intermediate guide tools include an attachment structure for operably connecting the guide tool to a bone screw. The attachment structure includes an undercut and/or recess so as to resist splaying and separation of the guide tool from an attached bone screw.