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.

Various methods and devices are provided for tensioning a tether. In one embodiment, a tether tensioning device is provided and includes a tensioning mechanism adapted to couple to a tether extending along a path between at least two bone anchors implanted in adjacent vertebrae. The tensioning mechanism can be adapted to apply a tensioning force to the tether along the path of the tether to thereby move the tether along the path. The device further includes an actuation mechanism movably coupled to the tensioning mechanism such that the actuation mechanism is adapted to effect movement of the tensioning mechanism to control the tensioning force applied to the tether.

A spinal fixation construct for aligning vertebral bodies includes a bone screw, a spinal rod, a flexible member, and a fixation member. The spinal rod is disposed within a saddle portion of a housing of the bone screw, and includes an elongated body having a first end and a second end. The spinal rod is formed from a first material having a first modulus of elasticity. The flexible member is coupled to the spinal rod, and includes an elongated body having a first end portion and a second end portion. The flexible member is formed from a second material having a second modulus of elasticity that is different from the first modulus of elasticity. The fixation member includes a threaded body portion and a head portion defining a hole therethrough. A portion of the flexible member extends through the hole of the head portion.

A spinal stabilization system including a connecting rod and a bone screw. The connecting rod includes an elongate rounded section, an elongate head portion, and a neck portion connecting the elongate rounded section with the elongate head portion. The bone screw includes a head portion defining a slot, a shank extending longitudinally from the head portion, and a set screw configured to secure the connecting rod in the slot. The head portion includes a pair of radially opposing walls defining the slot therebetween. The head portion includes a trailing end and a leading end. The trailing end includes a guide member defining an aperture configured and dimensioned to receive the set screw therethrough. The aperture is in communication with the slot. In particular, the guide member interconnects the pair of radially opposing walls.

Methods of correcting a spinal deformity, including securing a first rod on a first side of a spine, securing an anchor on a second side of a spine, securing a lateral coupling between the rod and the anchor, translating and derotating the spine to correct the spinal deformity by adjusting an effective length of the lateral coupling, and securing a second rod on a second side of the spine to provide secondary stabilization to the spine.

A spinal stabilization system includes a connecting rod, a rod bending device, and a plurality of bone screws. The connecting rod includes an elongate round portion, an elongate head portion and a neck portion connecting the elongate round portion with the elongate head portion. The rod bending device includes an elongate body defining an aperture configured and dimensioned to receive the connecting rod therethrough in a single orientation. The bone screws include a housing portion and a screw shaft distally extending from the housing portion. The housing portion includes an inner housing and an outer housing slidably surrounding at least a portion of the inner housing. The inner housing defines a slot configured and dimensioned to releasably secure the elongate round portion of the connecting rod therein. The outer housing is movable relative to the inner housing between an unlocked state and a locked state.

A pedicle screw for spinal fixation having a bone fastener portion a permanent rod coupling, a breakaway portion connected to the permanent rod coupling and a temporary rod coupling. A permanent rod can be positioned in the permanent rod coupling and a temporary rod can be positioned in the temporary rod coupling and when the temporary rod is not needed the temporary rod coupling can be removed by separation at a breakaway portion.

A spinal stabilization system includes a connecting rod and a bone screw. The connecting rod includes an elongate rounded section, an elongate head portion, and a neck portion connecting the elongate rounded section with the elongate head portion. The bone screw includes a head portion defining a slot, a shank extending longitudinally from the head portion, and a set screw configured to secure the connecting rod in the slot. The slot includes a leading end portion configured to receive the elongate rounded section of the connecting rod and a trailing end portion configured to threadably engage the set screw, wherein the slot is flared such that elongate rounded section of the connecting rod is pivotable about the leading end portion of the slot.

A system for fixing spinal vertebrae utilizes a spinal rod that has varying properties along its length such that a lower stiffness portion is placed in the cranial or caudal end positions of the spinal rod to address potential adjacent level failure. The spinal rod includes a core member formed of a first material having a first modulus of elasticity and a sheath member formed of a second material having a second modulus of elasticity different from the first modulus of elasticity. The core member includes a first portion having a uniform outer diameter and a second portion extending from the first portion. At least a portion of the second portion has an outer diameter smaller than the uniform outer diameter of the first portion. The sheath member has a lumen extending therethrough that is sized for slidably receiving the second portion of the core member therein.

A spinal fixation element rotation instrument with two lever arms is provided. The lever arms are connected to each other at distal ends thereof. The second lever arm rotates relative to the first lever arm. The distal ends of the first and second lever arms are adapted to couple to a spinal fixation element. The distal ends of the lever arms may have a dual ratchet feature that prevents rotation in a set direction. When one arm rotates back and forth, the other arm is held stationary. As a result, the spinal fixation element rotates in a predetermined direction and is prevented from rotating back toward its initial position. The direction of the rotation of the spinal fixation element may be set using knobs or switches provided at a proximal end of one or both of the lever arms.