A device for spinal correction includes a stabilizer assembly including a hinge including a first rod-bearing leaf; a second rod-bearing leaf rotatably coupled to the first rod-bearing leaf to provide coronal or sagittal freedom of movement, or both, of the stabilizer assembly; a locking mechanism to lock the first and second rod-bearing leaves at a desired angle; a first stabilizing rod coupled to the first rod-bearing leaf; a second stabilizing rod coupled to the second rod-bearing leaf; and a plurality of monoaxial or polyaxial links, wherein each monoaxial or polyaxial link is movably coupled to the first or second stabilizing rod and is movably couplable to a first spinal rod or a second spinal rod fixed to the spine; wherein the stabilizer assembly is couplable to the first or second spinal rod to stabilize the spine to prevent compression, distraction, or translation of the spinal cord during a spinal correction.

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 subsequent downward displacement of the insert within the through-space causing the opposed lower extensions to engage the capture head of a bone anchor with a frictional engagement that inhibits the bone anchor from moving upward within the through-space.

A polyaxial bone anchoring device includes a receiving part with a rod receiving portion defining a recess for receiving a rod, and a head receiving portion with a wall that defines an accommodation space for accommodating a head of an anchoring element, and a locking member positionable at least partially around the head receiving portion and movable from a first position where the head can pivot in the accommodation space to a second position where an angular position of the head is locked. The wall of the head receiving portion further defines at least one cavity in communication with the accommodation space that reduces a radial thickness of at least part of the wall located between the accommodation space and the locking member, and at least part of the cavity is separated radially from the accommodation space by a portion of the wall.

A receiver of a bone anchor includes a base and a pair of upright arms extending upward from the base to define an open channel for receiving an elongate rod, with the upright arms having opposed interior surfaces with a discontinuous guide and advancement structure formed therein and side outer faces opposite the opposed interior surfaces extending downward across the base to a bottom of the receiver. A horizontally-elongated upper tool engaging groove is formed into the side outer face of each upright arm that extends to at least a front face or back face of the upright arm and that includes a downwardly-facing upper surface, an upwardly-facing lower surface, and an outwardly-facing inner surface. A vertical tool-engaging groove is also formed into the side outer face of each upright arm that extends downward from a top surface of the upright arm through to a level below the lower surface of the upper tool engaging groove.

Various methods and apparatus for dynamic stabilization of bones, and especially of vertebra. Disclosed herein are bushings that permit axial movement of a rod, tether, or similar interconnection device relative to an anchoring head that is coupled to a bone. Some bushings further allow lateral relative movement or rotational relative movement, such additional relative movement being limited by the size and shape of the bushing, the size and shape of the interconnection device, the size and shape of the bushing container, the manner of attaching the anchoring head to the bone, or other considerations.

A bone fixation system where an alignment rod is engaged by pedicle screws. The alignment rod has sections of buttress thread. Each pedicle screw has a threaded shaft that supports a slotted receptacle. A set screw threads into the slotted receptacle. A locking plate is interposed between the set screw and the alignment rod. The locking plate contains protrusions that engage the sections of buttress thread on the alignment rod. The threaded shaft of the pedicle screw has an upper section and a lower section. A threaded connecting rod interconnects the sections. The upper section, lower section and threaded connecting rod all have external threads of the same thread pitch.

A pivotal bone anchor assembly includes a shank with a head and an anchor portion, and a receiver with a channel for receiving a rod and a lower portion of an axial bore for receiving the shank head, with the axial bore including a stop structure and a downwardly-facing surface beneath a helically wound thread. The assembly also includes an insert having an upwardly-facing seat, a lower surface for engaging the shank head, a side structure for engaging the stop structure, and an upwardly-facing surface positioned radially outward from the upwardly-facing seat, with the insert being installed into the axial bore in a first angular position. Subsequent rotation of the insert within the axial bore moves the upwardly-facing surface under the downwardly-facing surface to inhibit upward movement of the insert within the axial bore, with further rotation being inhibited by the side structure coming into engagement with the stop structure.

A polyaxial bone screw assembly includes a threaded shank body having an integral upper portion receivable in a receiver, the receiver having an upper channel for receiving a longitudinal connecting member and a lower cavity cooperating with a lower opening. The upper portion expands a retaining member in the receiver cavity to capture the shank upper portion in the receiver. In some embodiment either the retaining member or an insert provide for a friction fit of the shank upper portion in the receiver resulting in non-floppy placement of the shank with respect to the receiver. Some retainers and inserts have a lock-and-release feature. Final locking of the polyaxial mechanism is provided by frictional engagement between the shank upper portion and the retaining member. A pre-assembled receiver, retaining member and optional insert may be popped-on or snapped-on to the shank upper portion prior to or after implantation of the shank into a vertebra.

A pivotal bone anchor assembly includes a receiver comprising a base defining a central opening and upright arms defining an open channel for receiving a rod and including tool engaging structures for releasable overlapping engagement with an insert compressing tool. The assembly further includes a bone anchor comprising a capture head pivotably positionable within the central opening of the base and an anchor portion for fixation to the bone, and a compression insert positionable within the central opening above the capture head and comprising an upper surface engageable with the rod, a center through-bore, and upward-facing tool engagement surfaces located radially outward from the center through-bore. The tool engaging structures of the upright arms and the upward-facing tool engagement surfaces of the insert are configured for simultaneous non-threadable engagement with the insert compressing tool to apply a downwardly-directed force to the capture head to temporarily independently lock an articulated position of the bone anchor with respect to the receiver.

A method of inserting a spinal stabilization system into a patient generally comprises inserting a first positioning tool through a first location on a patient's skin and along a path generally toward a first vertebral anchor, coupling an end of the first positioning tool to the first vertebral anchor, positioning at least a portion of a delivery device over a connecting element, and inserting the delivery device and the connecting element through the patient's skin at the first location and along at least a portion of the first positioning tool. The first positioning tool is configured to facilitate directing the delivery device and connecting element generally toward a second vertebral anchor within the patient's body.