Abstract: A spinal stabilizing system includes a collar having a tubular sidewall with an interior surface and an exterior surface, the interior surface at least partially bounding a longitudinal passage extending therethrough. A shoulder radially inwardly projects from a second end of the sidewall so as to at last partially encircle the longitudinal passage. A pair of spaced apart channels transversely extend through the sidewall at the first end thereof. The system further includes a screw having a threaded portion and an enlarged head mounted on the end thereof, the head of the screw resting against the shoulder of the collar so that the head can pivot on the shoulder, a locking slot being formed on the head of the screw. A pin is secured to the collar and projects into the locking slot on the head of the screw such rotation of the collar facilitates rotation of the screw.

Abstract: A pedicle screw assembly and method of assembly comprises a longitudinal member; a screw head comprising a bulbous end, wherein the screw head has a slot adapted to receive the longitudinal member; a bone fixator component comprising a concave socket having a biased angled top and a rounded bottom adapted to receive the screw head; a locking pin adapted to engage the screw head, the bone fixator component, and the longitudinal member; and a blocker adapted to engage the screw head and to secure the longitudinal member. Additionally, the bone fixator component may be configured as any of a bone screw and a hook.

Abstract: A receiver body for an elongated spinal fixation element includes a housing portion with one or more flanges extending outwardly. In one embodiment, the receiver body includes first and second flanges extending outwardly from the housing portion. The housing portion includes first and second slots that form a passage through the housing portion. Each flange has a circular perimeter edge and a chamfered section, the chamfered section having a notched undercut for engagement with an instrument. In another embodiment, the receiver body includes a housing portion having a circular flange with a first chamfered section and a second chamfered section diametrically opposite the first chamfered section. The first chamfered section has a first aperture that opens out beneath the flange, and the second chamfered section has a second aperture that opens out beneath the flange. The first and second apertures form diametrically opposed pivot-attachment points for an instrument.

Abstract: The pedicle screw system may be used for fixation of spinal segments and may be advantageous when minimally invasive surgery (MIS) techniques are employed. The pedicle screw system includes a tulip assembly comprising of a tulip body, an inner member, and an expansion member. Installation of the pedicle screw system into pedicles of the spine, for example, includes inserting the pedicle screw into a portion of the spine and then coupling the tulip assembly to the pedicle screw. The tulip assembly may be locked onto the pedicle screw before a distraction rod is placed in the tulip assembly. After the rod is placed in the tulip assembly, the tulip body and the inner member can be rotated relative to one another to lock the rod into the tulip assembly. In addition, the relative rotation may also provide additional locking of the tulip assembly to the pedicle screw.

Abstract: A bone anchor can include an elongated body and a plurality of separate elements. The bone anchor can be configured to be insertable into bone. The bone anchor can be coupleable to a spine treatment apparatus. The bone anchor can be revisable so that after a treatment interval attached to a spine treatment apparatus, the spine treatment apparatus can be detached and the bone anchor revised by removing the plurality of separate elements from the bone thus allowing a new anchor to be implanted in the bone.

Abstract: The invention provides an osteosynthesis and compression screw that is self-boring and self-tapping for the purpose of coaptation of small bone fragments. The screw comprises: a proximal portion formed by a screw head provided with an outside thread; an intermediate portion having no thread; and a distal portion provided with an outside thread. Wherein: each of the screw head and the distal portion includes at least one groove, firstly extending over the entire axial length of its thread, and secondly being formed through each thread in such a manner to form tapping means; and the terminal zone of the distal portion is provided with preparation means for preparing a housing in the bone fragments for receiving the intermediate and distal portions of the screw.

Abstract: A dynamic screw assembly includes a screw head having a pair of diametrically opposed arms, a slot between the arms, an inwardly curved bottom portion, an outwardly protruding and expandable bulbous end extending from the inwardly curved bottom portion and an opening positioned through the bulbous end, a bumper mechanism adjacent to the screw head that adjusts an angle of the screw head to a desired location in the dynamic screw assembly, a fixation component coupled to the bumper mechanism, a saddle connection positioned in the opening and engaging the screw head and the fixation component, a longitudinal member positioned in the slot and a blocker coupled to the screw head and the longitudinal member.

Abstract: A dynamic screw assembly includes a fixation component that connects to a vertebral body, the fixation component includes at least one inlet to allow a lubricant to pass inside the fixation component, a ring member coupled to the fixation component, a stopper sealing at least one inlet, a coupling member includes an inwardly curved bottom portion and a bulbous end extending from the inwardly curved bottom portion, a bumper mechanism coupled to the fixation component and the coupling member, a longitudinal member coupled to the coupling member, and a blocker that retains the longitudinal member in the coupling member. The bulbous end includes at least one groove that houses the lubricant, and at least one slot to allow the bulbous end to fit into the fixation component and to limit a range of angulation of the coupling member with respect to the fixation component.

Abstract: A bone anchoring device includes a receiving part for receiving a rod, the receiving part has a first bore coaxial with a longitudinal axis and a second bore, and an anchoring element having a first end for insertion into the bone and a second end positionable within a second bore, the anchoring element being movable relative to the receiving part in limited angular range about the longitudinal axis, the angles lying in a single plane. The bone anchoring device further includes a fixation element cooperating with the receiving part to lock the anchoring element relative to the receiving part. The anchoring element is pivotable relative to the receiving part around one rotational axis transverse to the longitudinal axis.

Abstract: A receiving part for receiving a rod for coupling the rod to a bone anchoring element includes a receiving part body including: a rod receiving portion with a channel for receiving a rod, and a head receiving portion for accommodating a head of a bone anchoring element, the head receiving portion having an open end and being flexible for inserting and clamping of the head, and an exterior surface with a curved portion; and a locking ring around the head receiving portion, wherein the locking ring has an interior surface with a curved portion for engagement with the curved portion of the exterior surface of the head receiving portion for locking a position of the head relative to the head receiving portion.

Abstract: A pedicle screw for insertion into the pedicle portion of a vertebra and having at its exposed end a threaded rod connected in a generally parallel orientation to the longitudinal axis of the pedicle screw but laterally offset from the longitudinal axis of the pedicle screw. The threaded rod may be secured directly to the screw but is preferable provided with a collar that is captured by an enlarged screw head to seat, orient and retain the threaded rod in position. A locking arm and retaining nut are provided over the threaded rod for affixing a spinal rod to the pedicle screw substantially over and aligned with the longitudinal axis of the screw. A yoke may be provided in the collar also to receive and secure the rod. An alternate cap and clamping elements enable the incorporation of cross links between multiple screws and/or rods.

Abstract: A receiving part for coupling a rod to a bone anchoring element includes a receiving part body including a rod receiving portion having a channel for receiving a rod, and a head receiving portion for accommodating a head of a bone anchoring element, the head receiving portion having an open end and being flexible for inserting and clamping of the head; and a locking ring around the head receiving portion, wherein in a pre-locking position, a spring portion on one of the locking ring or the receiving part body engages a corresponding portion on the other one of the locking ring or the receiving part body, and the locking ring exerts a first force onto the head receiving portion, and wherein in a locking position, the locking ring exerts a second force greater than the first force onto the head receiving portion to lock the head therein.

Abstract: A locking mechanism (100) and method of fixation, such as the fixation of a fixation device (104) like a bone screw and of a rod (106) to the spine. The locking mechanism (100) includes a body (102), an insert (108, 308), a rod seat (110, 310) and a set screw. The body (102) includes a bottom portion (114) configured to receive the fixation device (104) and the insert (108, 308) but prevents the insert (108, 308) and fixation device (104) from passing therethrough once the insert (108, 308) and fixation device (104) are engaged. The body (102) further includes a side portion (120) configured to receive the rod (106). Between the rod (106) and the insert (108, 308) is a rod seat (110, 310).

Abstract: A method of assembling a bone anchor assembly is presented. The bone anchor assembly includes a bone anchor and housing configured to receive the bone anchor and a longitudinal member. The bone anchor is inserted into a passage in the housing and material is swaged to retain the bone anchor in the housing. The material that is swaged is a portion of the housing or additional material added to the assembly.

Abstract: A spinal cross connector head assembly and a cross connector assembly utilizing the spinal cross connector head assembly are configured for fixation to an existing spinal rod bone screw head. The spinal cross connector head assembly has one or more components which incorporate one or more breakaway portions that aid in the installation of the cross connector head assembly onto a polyaxial spinal rod bone screw assembly. The spinal cross connector assembly includes first and second spinal cross connector head assemblies each of which is configured for fixation to existing, adjacent spinal rod screw heads and connection with a cross connector rod.

Abstract: Systems for positioning a connecting element adjacent the spinal column in minimally invasive procedures include installation instruments that guide the connecting element from a location remote from one or more anchors to a location proximate to the one or more anchors. The installation instruments include extensions mountable to anchors engageable to the spinal column or other bony structure, and inserters mountable to the anchor extensions for positioning the connecting element adjacent the anchors.

Abstract: A method of treating the spine of a patient involves inserting anchors into vertebrae and connecting the anchors to a longitudinal member via housings. After insertion of the anchors, the housings containing a longitudinal member are positioned over the anchors and fastened.

Abstract: A poly-axial bone fastener assembly having a collar and a bone fastener can be coaxially locked to prevent poly-axial movements of the collar relative to the bone fastener while permitting the collar to rotate about an axis of the bone fastener, thereby combining the functions and advantages of a poly-axial bone screw and a fixed angle bone screw. Some embodiments of a coaxial locking mechanism may include a c-clip with a locking pin, a c-clip with hooks, a split ring with square corners, a pin that spins inside the collar, pins that travel about a neck of the bone fastener, a coaxially locking top that screws into the collar over a head of the bone fastener, and a top nut that threads onto the head of the bone fastener inside the collar to trap a flange of the collar between a shoulder of the bone fastener and the top nut.

Abstract: A locking mechanism (100) and method of fixation, such as the fixation of a fixation device (104) like a bone screw and of a rod (106) to the spine. The locking mechanism (100) includes a body (102), an insert (108, 308), a rod seat (110, 310) and a set screw. The body (102) includes a bottom portion (114) configured to receive the fixation device (104) and the insert (108, 308) but prevents the insert (108, 308) and fixation device (104) from passing therethrough once the insert (108, 308) and fixation device (104) are engaged. The body (102) further includes a side portion (120) configured to receive the rod (106). Between the rod (106) and the insert (108, 308) is a rod seat (110, 310).

Abstract: A tulip assembly configured to be coupled to a head of a bone fixation device includes at least one inner member configured to fix the tulip assembly to the head of a bone fixation device, and an outer member including at least one engagement surface configured to selectively fix a rod in the tulip assembly via rotation of the outer member, wherein the fixation of the tulip assembly to the head of the bone fixation device is independent of the fixation of a rod in the tulip assembly.

Abstract: A porous PEEK implant system which may provide tissue ingrowth throughout the body of the implant. The implant may comprise a solid or porous PEEK core. The porous PEEK implants may be of general shape and size but provide the structure necessary to carry out the function of the implant. The porous PEEK implant pores may be seeded with agents to encourage tissue ingrowth as well as other agents such as antibiotics, anesthetics, analgesics and the like.

Abstract: A spine stabilization prosthesis which supports the spine while providing for the preservation of spinal motion. The spine stabilization prosthesis incorporates a bone anchor having a deflectable post and a compound spinal rod which provide for load sharing while preserving range of motion and reducing stress exerted upon the bone anchors and spinal anatomy. The bone anchor includes a deflectable post connected by a ball-joint to a bone screw. The compound spinal rod includes a coupling mounted to the deflectable post and connected by a pivoting joint to a rod. The combined motions of the ball-joint and the pivoting joint support a range of motion of adjacent vertebrae which closely approximates the natural range of motion of the spine.

Abstract: A cannulated screw which maintains compression at the interface between two or more materials in a medical or other setting to effectively secure bone to bone while minimizing separation between the bones and the securement interface. The cannulated screw has a flattened tip, which enables the cannulated screw to more readily bore or self-tap into bone or other material. The flattened tip of the cannulated screw comprises a plurality of cutting teeth which facilitate boring of the flattened tip of the cannulated screw into the material into which the screw is being inserted. In one embodiment, three progressive cutting teeth are provided on the flattened tip of the cannulated screw.

Abstract: A pedicle screw fastening that can be made polyaxial, monoaxial, fixed, or provide a predefined monoaxial placement. The fastening system consists of an anchoring bone screw having threads on one end for use in anchoring to the screw to the spine and a spherical connector on the other end operating as a pivot point about which a U-shaped or side loading connecting assembly is used to secure to a connecting rod for use in stabilization of a spine. The connecting assembly, for receipt of a spinal connecting rod, includes a biased retainer ring for maintaining a positive tension between the connecting assembly and the anchored screw. The system allows for an improved manufacturing step wherein the threaded shank of a bone screws can be passed through a lower portion of the connecting assembly allowing a variety of bone screw sizes to be used with a common sized connector.

Abstract: The invention relates to a bone screw with a shaft that defines a longitudinal axis and with a head that is configured as a thickened portion, said shaft and head being threaded. The thread of the shaft (bone thread) merges in an uninterrupted manner into the thread on the flared area of the head adjoining the shaft. As a result, part of the threaded head lies in the osseous tissue, giving a larger contact surface between bone screw and bone and improving the distribution and transmission of the loads and forces.

Abstract: A method of conducting a surgical procedure including implanting an anchor into a bone, wherein the anchor comprises a receiving portion and a screw, the screw including a screw head contained within the receiving portion and pivotally engageable with a surface of the receiving portion, and wherein the receiving portion and the screw comprising a different material. The method further includes selecting a rod from a group of rod types and coupling the rod with the receiving portion to stabilize a position of a portion of the spine.

Abstract: The present invention generally provides a polyaxial fixation device having a shank with a spherical head formed on a proximal end thereof, and a receiver member having an axial passage formed therein that is adapted to polyaxially seat the spherical head of the shank. The polyaxial bone screw further includes an engagement member that is adapted to provide sufficient friction between the spherical head and the receiver member to enable the shank to be maintained in a desired angular orientation before locking the spherical head within the receiver member.

Abstract: In one aspect, a bone anchor assembly is provided. The bone anchor assembly includes a bone anchor, a crown member, a saddle, and a sleeve. The bone anchor assembly is configured such that the bone anchor is moveable with respect to the saddle when the sleeve is positioned around the saddle and the bone anchor is locked relative to the saddle by compression of the head portion of the bone anchor between the crown member and a seat of the saddle. In another aspect, a system for orthopedic implantation is provided. The system includes an elongated member, a compression member, and a bone anchor assembly. In another aspect, a method of assembling a bone anchor assembly is provided.

Abstract: A polyaxial ball and socket joint that can be locked into a fixed position. The fastening system consists of the polyaxial ball and socket joint used in conjunction with a bone screw having threads on one end for use in anchoring to the spine and a spherical connector on the other end operating as a pivot point about which a connecting assembly moves in a polyaxial fashion. A substantially U-shaped connecting assembly has a lower receptacle that operates as a socket for housing an upper retainer ring and a lower split retaining ring. The socket is receptive to the spherical connector which is inserted through the lower split retainer ring causing a momentary displacement thereof which allows for the positioning of the spherical connector between the upper and lower retainer rings.

Abstract: A spinal fixation assembly includes a spinal rod, a first spinal fixation device, and a locking element. The spinal rod defines a longitudinal axis. The first spinal fixation device includes a coupling, a screw, and a collet. The coupling has an opening extending therethrough. The screw is mounted to the coupling and positionable within a first vertebral body. The collet is receivable in the opening of the coupling and defines a saddle for engaging the spinal rod. The locking element is mounted to the spinal rod and is configured to prevent axial translation of the spinal rod in one or both directions along the longitudinal axis thereof.

Abstract: A pedicle screw construct includes a pedicle screw, a coupling, a collet, and a set screw. The pedicle screw includes a shank having a helical thread formed thereon and a head at one end. The collet is positioned atop the head of the pedicle screw. The collet and pedicle screw are inserted into the coupling. The set screw is positioned in the collet such that the set screw contacts a portion of the rod and is releasably secured to the pedicle screw via a gripping tool. The pedicle screw is rotatable and pivotable relative to the collet and coupling assembly.

Abstract: A spinal fixation device includes a coupling, a pedicle screw, and a collet. The coupling has an opening extending therethrough. The pedicle screw has a head mounted to a shank that is positionable within a first vertebral body. The collet is receivable in the opening of the coupling and engagable with the head of the pedicle screw. The collet is selectively positionable between a first position and a second position where the collet engages a spinal rod and prevents one or both of axial and rotational movement of the spinal rod. The collet is adapted to facilitate the connection of the spinal rod to a second vertebral body. The collet defines a saddle having one or more locking features for engaging the spinal rod.

Abstract: An anchor with a non-threaded securing mechanism for attaching an elongated member to a bone. The anchor includes a receiver, shaft, and securing mechanism. The receiver includes spaced-apart arms that form a channel sized to receive the elongated member. The shaft extends from the receiver and is configured to engage with the bone. The securing mechanism, including a base and an insert, attaches to the receiver to capture the elongated member in the channel. The base is configured to attach to the arms and includes an aperture that receives the insert. The insert extends through the aperture and may contact against the elongated member.

Abstract: Spinal surgery systems are provided. In one embodiment, a system includes threaded caps and screw assemblies. Each assembly includes a cannulated and threaded screw having upper and lower ends, a polyaxial head permanently fixed to the screw upper end in a ball-and-socket engagement, and an extension portion fixed to the head wherein extension portion movement causes the head to move in concert. Each head has a receiving area for engaging a rod and a threaded area for receiving one of the caps after the rod is engaged in the receiving area. Each extension portion has: (a) two arms spaced apart such that the arms are on opposite sides of the polyaxial head receiving area; and (b) at least one point of weakness such that forcing the arms away from one another causes the extension portion to divide at the point of weakness and separate the extension portion from the head.

Abstract: A system for stabilization of the spinal column, including an elongate support member extending along an axis and a plurality of anchor members configured for anchoring to respective vertebrae. A first of the anchor members is engaged to the support member in a manner that substantially prevents axial movement of the support member relative to the first anchor member, and a second of the anchor members is engaged to the support member in a manner that allows substantially unconstrained axial movement of the support member relative to the second anchor member. In a further embodiment, a third of the anchor members is engaged to the support member in a manner that also allows substantially unconstrained axial movement of the support member relative to the third anchor member, with the second and third anchor members positioned on opposite sides of the first anchor member.

Abstract: A device to attach an elongated member to a bone in a patient with the device including a receiver with arms that are spaced apart that form a channel sized to receive the elongated member, and a groove on an inner surface of at least one of the arms. A shaft may be operatively connected to the receiver and configured to attach to the bone. A securing mechanism is attached to the receiver that includes an outer member and an inner member. The outer member may include a bore and a non-threaded exterior that may be configured to engage with the groove to attach the securing mechanism to the receiver. The second member may be sized to fit in the bore and move axially along the bore in a non-rotational manner. The second member may also include a compressible extension sized to fit in the bore when the extension is moved in the bore and to expand to a width greater than the bore when the second member extends outward beyond the bore.

Abstract: Procedures for the fusion of the sacroiliac joint advantageously make use of an implant selected to distract the joint upon insertion and to maintain or increase tension upon insertion. The implant can have a varying structure along its length. In some method described herein for fusing the sacroiliac joint using an implant, an implant is screwed into the sacroiliac joint between the sacrum bone and the iliac bone. The implant comprises a shaft, a tool engagement flange at top end of the shaft, a pointed tip comprising no more than about 20 percent of the length of the screw, and threads spiraling around the shaft. For screws of particular interest, the volume displacement perpendicular to the shaft increases at least about 5 percent from a point adjacent the tip to a point near the top of the shaft. Some of the desirable screw designs can be used in other orthopedic application, especially situations involving varying bone hardness.

Abstract: A lock screw assembly for use with a pedicle screw assembly comprises a lock screw and an upper saddle. The lock screw includes a fastening tool engaging structure at a first end portion thereof and an upper saddle receiving structure at a second end portion thereof. The upper saddle is engaged with the upper saddle receiving structure of the lock screw in a manner allowing the upper saddle to rotate about a centerline axis of the lock screw. A plurality of intersecting spine rod receiving channels extend through a spine rod engaging portion of the upper saddle in a manner such that an outwardly-extending spine rod engaging structure is provided between adjacent ones of the spine rod receiving channels. Upper and lower surfaces of each spine rod engaging structure are acutely angled with respect to each other and wherein a channel edge defined between the surfaces is sharply pointed.

Abstract: Devices and methods include a multi-axial anchor assembly engageable to a vertebra and a connecting element positionable through a receiver of the anchor assembly. The anchor assembly includes a flexible member between the receiver and an anchor member of the anchor assembly, thereby providing a flexible joint in the anchor assembly for allowing limited movement after primary multi-axial capability between the receiver and the anchor member has been arrested.

Abstract: A system and method for a multi-axial connection of an apparatus to bone. The system may include a fastener inserted into a body and a head of the fastener held within a chamber of the body through a combination of a retention ring, a pressure cap, a rod, and a compression element. The compression element applies force to the rod which, in turn, pushed on the pressure cap. The force on the pressure cap urges it against the head of the fastener and pushed it against the retention ring. The force on the retention ring causes it to expand to the walls of the chamber. Once the ring can no longer expand within the chamber, the head of the fastener is wedged between the retention ring and the pressure cap.

Abstract: The present invention provides a bone screw which can be used for fixation and/or fastening of prosthetic devices or instruments to bone tissue whose structure or dimensions differ from one region to another. In particular, the present invention provides a bone screw which is designed to optimize purchase in both the cancellous and cortical regions of a vertebral body. In an exemplary embodiment, the bone screw has a distal portion and a proximal portion in which the diameter of the thread on the proximal portion of the screw is greater than the diameter of the thread on the distal portion of the screw.

Abstract: A bone anchoring element includes an anchoring section for anchoring in the bone and a receiving part connected to the anchoring section. The receiving part includes an opening suitable for accommodation of a stabilization rod having a rod axis, the opening being limited along the rod axis by two side walls. The side walls include guides orientated along the rod axis for guiding at least one connection rod therethrough.

Abstract: The present disclosure provides a cannulated bone screw system including a screw with a threaded portion, a non-threaded portion, and a first plurality of teeth spaced apart from a screw head; and a washer with an interior portion with a second plurality of teeth and an opening and an outer portion with a plurality of spikes. The first plurality of teeth are on an inferior convex surface; wherein the second plurality of teeth are on a superior concave surface; and wherein the first plurality of teeth and the second plurality of teeth are operable to mate to prevent the screw from backing out of the washer while allowing the cannulated bone screw system to conform/pivot in order to accommodate different bone morphologies.

Abstract: Disclosed is a pedicle screw. By changing the structure of a threaded portion of a locking bolt engaged with a head of the pedicle screw and forming a groove on the locking bolt, the threaded portion is pressed in a fastening direction of the locking bolt, so that when a head of the pedicle screw is fastened to the locking bolt, a fixation cap is not released by the force applied from the head expanding towards an outside, and thus the locking bolt is easily fastened to the head of a screw body, thereby improving an inefficiency factor such as delay of surgical operation time due to release or interference of the fixation cap.

Abstract: A bone fixation assembly for securing a fixation device such as a bone plate, to bone includes a fixation device, including at least a through hole with isolated protrusions (such as pegs or spikes); and locking bone engaging members such as screws. The screw has a shank with a thread for engaging bone and a partial sphere head with a thread configured and dimensioned to match with the isolated protrusions of the hourglass shaped through holes of the bone plate. The bone plate has a through hole shaped like an hourglass which diameter matches that of the screw spherical head and is provided with multiple isolated protrusions. In use, the screw is threaded into the bone, through the hole of the bone plate at a selected angle. The partial sphere head of the screw engages in the protrusions of the plate hole resulting in the strong locking of the screw at the selected orientation within the through hole in just one single surgical action.

Abstract: An orthopedic screw assembly including a proximal member positioned at a proximal end of the orthopedic screw assembly, a distal member positioned at a distal end of the orthopedic screw assembly, and an elongate element having a first end and a second end. The elongate element is coupled to the proximal member at the first end and coupled to the distal member at the second end. The elongate element is configured to apply a dynamic compressive force on each of the proximal member and the distal member, thereby coupling the proximal member to the distal member.

Abstract: A polyaxial screw assembly includes an internal load dampening mechanism for sharing and dampening loads between at least one screw member and at least one rod member interconnected by the assembly. A method of interconnecting the orthopedic screw with the rod by dampening with a body member interconnecting the screw to the rod.

Abstract: The present application is directed to connectors for attaching a vertebral rod to an anchor. The connectors may include a body with a first channel to receive the vertebral rod and a second channel to receive the anchor. A cradle may be positioned in the body to contact the vertebral rod. The cradle may be pivotally positioned in the body to accommodate a vertebral rod that is at various angular positions within a predetermined plane. A set screw may engage with the body to secure the vertebral rod to the body and the body to the anchor.

Abstract: A polyaxial screw assembly includes an internal load dampening mechanism for sharing and dampening loads between at least one screw member and at least one rod member interconnected by the assembly. A method of interconnecting the orthopedic screw with the rod includes dampening with a body member interconnecting the screw to the rod.

Abstract: A tulip assembly configured to be coupled to a head of a bone fixation device includes at least one inner member configured to fix the tulip assembly to the head of a bone fixation device, and an outer member including at least one engagement surface configured to selectively fix a rod in the tulip assembly via rotation of the outer member.