A polyaxial bone screw assembly includes a threaded shank body having an upper portion, a receiver member or head, a retaining and articulating structure, and a pressure insert disposed between the shank upper portion and a rod. The receiver has a U-shaped cradle defining a channel for receiving a spinal fixation rod and a receiver cavity. The retaining and articulating structure attaches to the shank and rotates with the shank in the cavity during positioning. The pressure insert presses upon the shank upper portion and not the retaining and articulating structure.

A bone screw assembly includes an anchor portion and a head portion, such as a rod-receiving portion, movably mounted to the anchor portion to allow for controlled angulation between the anchor portion and the head portion. The anchor portion is pivotable in one or more selected directions about an axis relative to the head portion. A restriction member, which may be a rod seat, prevents the anchor portion from pivoting in one or more different directions about another axis relative to the head portion and/or a spinal fixation element received in the head portion. The restriction member may be inserted in the head portion to control direction that the anchor portion pivots relative to the head portion. The restriction member may also serve as a compression member and/or rod seat for seating a spinal rod coupled to the bone screw assembly.

Systems and methods include solutions for fixation at the rib head for fractures and osteotomies adjacent to the rib head and transverse process. The disclosed rib plates, anchor systems, other implants, and instrumentation may also be applied to mid-rib fractures. The systems and methods may be used in the treatment of rib deformities, including the correction of rib hump deformity via thoracoplasty, as well as general corrections of chest and rib deformities. Systems and methods herein may be used in chest wall reconstructions due to trauma, cancer, or deformity.

Disclosed implants may include a first implant receiver and a second implant receiver each having an upper portion and a lower portion connected together by an arm portion, for example. In various embodiments, the upper and lower portions may define a longitudinal passageway extending through the upper and lower portions in a longitudinal direction of each implant receiver, and the arm portions may each define a rod passageway extending in a lateral direction, for example. In various embodiments, each receiver may include a crown having an outside thread pattern threadably engaged within the longitudinal passageway and for mating with a corresponding nut having a similar interior thread pattern. In various embodiments, a rod may extend in the lateral direction through the rod passageways In various embodiments, in a non-tightened position, the rod may freely move and in a tightened position, the arms constrain the rod from moving.

Modular orthopedic implants, associated instruments, and navigation methods. The modular orthopedic fixation assembly may include a modular bone fastener and a modular tulip head configured to be installed separately. The modular bone fastener may be installed and tracked with a screw extender instrument having an outer sleeve and an inner shaft coupled to the bone fastener. The screw extender instrument may continue to track the location and orientation of the bone throughout the surgical procedure for navigational integrity. The modular tulip head may be assembled to the bone fastener with a head inserter instrument, which ensures the modular head is properly seated on the installed bone fastener.

A pedicle bone fastener may include a shaft, a helical thread, and an integrated attachment feature. The shaft may include a proximal end, a distal end, and a longitudinal axis. The helical thread may be disposed about the shaft along the longitudinal axis between the proximal and distal ends of the shaft. The helical thread may include a first undercut surface and a second undercut surface. The first undercut surface may be angled toward one of the proximal end and the distal end of the shaft and the second undercut surface may be angled toward the other one of the proximal end and the distal end of the shaft. The integrated attachment feature may be disposed at the proximal end of the shaft and configured to be adjustably secured to a spinal stabilization implement.

Disclosed implants may include a first implant receiver and a second implant receiver each having an upper portion and a lower portion connected together by an arm portion, for example. In various embodiments, the upper and lower portions may define a longitudinal passageway extending through the upper and lower portions in a longitudinal direction of each implant receiver, and the arm portions may each define a rod passageway extending in a lateral direction, for example. In various embodiments, each receiver may include a crown having an outside thread pattern threadably engaged within the longitudinal passageway and for mating with a corresponding nut having a similar interior thread pattern. In various embodiments, a rod may extend in the lateral direction through the rod passageways In various embodiments, in a non-tightened position, the rod may freely move and in a tightened position, the arms constrain the rod from moving.

A bone screw includes a shank having a longitudinal axis, a tip configured to be inserted first into bone, a core, and a thread with a plurality of turns winding in a helix around at least part of the core to engage bone. The thread has a lower flank and an upper flank, wherein for a first section of the thread, the upper and lower flanks form a first angle for at least one full turn, and wherein for a second section of the thread, the upper and lower flanks form a second angle for at least one full turn that is greater than the first angle. An outer diameter of the second section adjacent to the first section is at least as wide as an outer diameter of the first section adjacent to the second section.

A system for replacing at least a portion of a natural facet joint includes a fixation member implantable in a vertebra, an inferior facet articular surface and an inferior strut which may be formed separately from the inferior articular surface. The inferior strut has a first end securable to the fixation member and a second end which may comprise a sphere with a hemispherical surface. An attachment mechanism may include a capture feature shaped to receive the second end of the inferior strut, and the mechanism may provide an adjustable configuration, allowing polyaxial adjustment between the inferior articular surface and the second end. A locking member may be actuated to exert force on the second end to provide a locked configuration. The system may further include a superior facet joint implant with a superior articular surface shaped to articulate with the inferior articular surface.

A bone attachment assembly may include an attachment head, a set screw configured to attach to the attachment head, and a rod surface with a first raised portion and a second raised portion that define a lowered portion positioned between the first raised portion and the second raised portion. The first raised portion, the second raised portion, and the set screw may be configured to directly contact a rod in order to retain the rod within the attachment head.