Abstract: A polyaxial bone anchoring device includes a bone anchoring element having a head and a shaft, a receiving part having a head receiving portion, a rod receiving portion, and a bore having a bore axis, and a pressure member movable in the bore and having a first surface for engaging the head, wherein the pressure member is movable to a first position where friction between the first surface and the head generates a preload on the head to maintain the shaft at a temporary angular position relative to the receiving part, and wherein the pressure member is configured to engage the receiving part to generate a holding force for holding the pressure member at the first position without a positive lock, and wherein the pressure member is movable in and out of the first position by applying an axial force on the pressure member greater than the holding force.

Abstract: An apparatus and method related to a collet for a spinal screw are described herein. In some embodiments, such an apparatus includes a screw, a movable head comprising a top portion and a bottom portion, a concave interior larger than a screw head, a connecting rod, a locking element screw, and a collet interposed between the screw head and the concave interior of the movable head, where the collet comprises a flexible hinge, and where the collet reduces axial compression force transferred from the set screw to the screw head.

Abstract: A spinal fixation device is provided including a modular head assembly and a bone screw. The modular head assembly includes a housing, an anvil, an insert, and a snap ring. The housing defines a proximal surface and an opposite, distal surface, and the proximal and distal surfaces define a throughbore therethrough. The anvil is configured to be slidably received within a portion of the throughbore. The insert defines a proximal surface and an opposite, distal surface, and the distal surface defines a first counterbore therein that terminates at a first annular surface. The first annular surface defines a second counterbore that terminates at a second annular surface. The snap ring is configured to be disposed within the first counterbore of the insert when in a first configuration, and within the second counterbore of the insert when in a second configuration.

Abstract: 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.

Abstract: A polyaxial bone screw assembly includes a receiver, a shank, an articulation structure for retaining the shank in the receiver and a compression insert for engagement with a longitudinal connecting member such as a rod. The articulation structure includes substantially spherical convex and concave surfaces that slidably engage both shank and receiver surfaces to provide compound articulation between the receiver and the shank. The receiver includes inwardly directed spring tabs engaging the insert and prohibiting rotation of the insert within the receiver.

Abstract: A bone fastener includes a receiver defining an implant cavity and having an inner surface defining a slot. A band is disposable within the slot. A spacer disposable within the slot. A crown is rotatable relative to the receiver to translate the spacer relative to the inner surface such that the spacer orients the band in a capture orientation with the shaft. A screw shaft connectable with the receiver by the band and configured to penetrate tissue. Implants, systems, instruments and methods are disclosed.

Abstract: To provide a bone fixation device able to firmly fix bone elements. A bone fixation device, comprising: a base section having a first space that holds a rod; a hook formed with a second space in which a bone element is accommodated together with a art of the base section; and a sandwiching part that is installed to the base section and that sandwiches the bone element which has been accommodated in the second space together with a pail of the hook, wherein the sandwiching part is shiftable allowing attachment to the bone element.

Abstract: A bone anchoring device includes a receiving part configured to pivotably receive a head of an anchoring element, a pressure member positionable and movable in the receiving part, and an insert member positionable at least partially in the pressure member and movable axially relative to the pressure member between a first position and a second position for exerting an adjustable pressure on the head of the anchoring element. A first engagement structure of the insert member that has at least one of an upwardly facing engagement surface or a downwardly facing engagement surface is configured to engage a second engagement structure of the pressure member to releasably hold the insert member at the first position against movement towards the second position and to releasably hold the insert member at the second position against movement towards the first position.

Abstract: A polyaxial bone anchoring device includes: an anchoring element having a shaft for anchoring in a bone and a head, the head having a spherically-shaped outer surface portion; a receiving part configured to be pivotably connected to the head, the receiving part having a top end and a bottom end, a longitudinal axis extending through the top end and the bottom end, a channel transverse to the longitudinal axis for receiving a rod, and an accommodation space for accommodating the head, the accommodation space having a lower opening at the bottom end, a sleeve-like insert piece configured to be positioned around a portion of the head and to pivot in the receiving part, the insert piece having a spherically-shaped outer surface portion, wherein a lower edge of the insert piece extends past the lower opening in a direction away from the receiving part when the insert piece is seated in the receiving part in a position in which a central axis of the insert piece is coaxial with the longitudinal axis, and wherein th

Abstract: A spinal construct includes a fastener configured for attachment with sacral and/or pelvic tissue of a body. A connector includes a mating element engageable with the fastener and includes a receiver. A spinal implant is engageable with the receiver between a capture configuration and a removable configuration. A multi-axial fastener is connected with the spinal implant. Systems, implants, instruments and methods of use are disclosed.

Abstract: Connector assemblies, systems, and methods thereof. A connector has a first end that clamps to a first rod in an existing construct and a second end, connected to the first end, that clamps to a second rod in a new construct such that the new construct can be extended from the existing construct at an adjacent level as the existing construct.

Abstract: A tethering screw system includes a bone screw, a fastening member, and a securing member. The bone screw includes a threaded shank and a head portion. The head portion includes inner walls defining a slot and a recess distal of the slot. The fastening member is received in the recess of the head portion of the bone screw. The securing member has an engaging portion and a set screw rotatably coupled with the engaging portion. The engaging portion is configured to secure the fastening member in the recess of the head portion. The set screw is configured to threadably engage the inner walls of the head portion of bone screw, wherein when the set screw threadably engages the inner walls of the head portion of the bone screw, the engaging portion advances relative to the fastening member to secure the fastening member in the recess of the head portion.

Abstract: A polyaxial bone anchoring device includes a bone anchoring element having a head and a shaft, a receiving part having a head receiving portion, a rod receiving portion, and a bore having a bore axis, and a pressure member movable in the bore and having a first surface for engaging the head, wherein the pressure member is movable to a first position where friction between the first surface and the head generates a preload on the head to maintain the shaft at a temporary angular position relative to the receiving part, and wherein the pressure member is configured to engage the receiving part to generate a holding force for holding the pressure member at the first position without a positive lock, and wherein the pressure member is movable in and out of the first position by applying an axial force on the pressure member greater than the holding force.

Abstract: A system includes a first pedicle screw, a second pedicle screw, and an adjustable rod having an outer housing coupled to one of the first pedicle screw and the second pedicle screw, the outer housing having a threaded shaft secured to one end thereof extending along an interior portion thereof. The system further includes a hollow magnetic assembly disposed within the outer housing and having a magnetic element disposed therein, the hollow magnetic assembly having an internal threaded surface engaged with the threaded shaft, the magnetic assembly being coupled to the other of the first pedicle screw and the second pedicle screw, wherein the hollow magnetic assembly rotates in response to an externally applied magnetic field to thereby lengthen or shorten the distance between the first pedicle screw and the second pedicle screw.

Abstract: The present invention generally relates to connectors that connect bone screws with fusion rods for use in stabilizing surgery such as spinal fusion surgery, and to bone screw systems comprising such connectors. In particular, the present invention relates to poly axial screw systems configured to provide a stable but adjustable angular placement. Furthermore, embodiments of the present invention relate to tulip connectors which have a head and a collet, that are configured to rotatably and pivotably lock onto the ball head of a poly axial screw shaft into a manually adjustable locked position, to methods achieving this locked position with or without using a tulip assembly tool, and to the tulip assembly tool that has outer hooks to grab the tulip head and a center dowel to push the collet down into the locked position.

Abstract: The bottom loading fastening system that consists of the polyaxial ball and socket joint used in conjunction with a bone screw. The system allows attachment to a bone screw using a retaining ring spot welded to a blocker ring to assure proper ring positioning. Upon installation the retainer wall is expanded causing a break from the blocker ring producing an audible and tactile indication that the sufficient force has been applied to set the retainer and blocker rings locking the bone screw to a U-shaped connecting assembly.

Abstract: A polyaxial bone screw assembly includes a threaded shank body having an integral shank head receivable in a one-piece receiver having an upper channel for receiving a longitudinal connecting member and a lower cavity cooperating with a lower opening. A compression insert (some with an independent tool lock, lock and release feature and/or friction fit feature) and a split retaining ring articulatable with respect to both the shank head and the receiver (prior to locking) cooperate with the receiver to provide for pop- or snap-on assembly of the shank with the receiver either prior to or after implantation of the shank into a vertebra.

Abstract: A bone fastener includes a first portion that defines a longitudinal axis and includes an inner surface defining an implant cavity. A second portion that includes a first end and a second end configured to penetrate tissue. A retainer includes a wall having a first end surface and a second end surface. The wall including at least one first elongated cavity and at least one second elongated cavity. The first cavity includes a gap of the first end surface and the second cavity including a gap of the second end surface. The wall further includes an inner surface disposed about the first end. Systems and methods are disclosed.

Abstract: A polyaxial bone screw assembly includes a threaded shank body having an integral upper portion receivable in an integral receiver, the receiver having an upper channel for receiving a longitudinal connecting member and a lower cavity cooperating with a lower opening. A friction fit compression insert (some with lock and release feature), a planar split retaining ring and a shank upper portion cooperate to provide for pop- or snap-on assembly of the shank with the receiver either prior to or after implantation of the shank into a vertebra. The shank and receiver once assembled cannot be disassembled and the receiver and insert may include aligned tool receiving apertures for lock and release of the polyaxial mechanism.

Abstract: A polyaxial bone screw assembly includes a threaded shank body having an integral upper portion receivable in an integral receiver, the receiver having an upper channel for receiving a longitudinal connecting member and a lower cavity cooperating with a lower opening. The receiver can have crimp tabs, but is devoid of spring tabs and collet-like flexible structures. A down-loadable compression insert (some with lock and release feature), a down-loadable friction fit split retaining ring and an up-loadable shank upper portion cooperate to provide for pop- or snap-on assembly of the shank with the receiver either prior to or after implantation of the shank into a vertebra. The shank and receiver once assembled cannot be disassembled. The receiver and insert include aligned tool receiving apertures for lock and release of the polyaxial mechanism.

Abstract: A receiving part for coupling a bone anchor to a rod is provided, where the bone anchor includes a shank for anchoring to a bone or a vertebra. The receiving part includes a first end and a second end, the second end being connected to the shank, a bore extending from the first end into the receiving part for receiving a fixation device, the bore having a bore axis, and a recess for receiving a rod, the recess being open at the first end of the receiving part for allowing insertion of the rod and having opposing sidewalls on at least one side of the bore. When a rod is inserted into the recess, a longitudinal axis of the rod extends substantially perpendicular to the bore axis. A resilient retention element is provided on at least one of the opposing sidewalls, where the resilient retention element is deflectable toward the at least one sidewall when the rod is inserted.

Abstract: Open implant closure structures include a helically wound guide and advancement flange form having pivot-splay accommodating and splay control surfaces with opposing load flanks in initial non-parallel relation.

Abstract: A bone anchoring device includes an anchoring element having a shank to be anchored in a bone or a vertebra and a receiving part connected to the shank, and a rod for connecting at least two anchoring elements, the rod having at least a tubular portion. The receiving part comprises a recess for receiving said rod. The bone anchoring element also includes a locking element cooperating with the receiving part to secure the rod in the recess, a filling piece being arranged between the locking element and the rod for exerting pressure onto the rod to lock the rod in the recess. The filling piece includes a rod contacting surface which contacts a portion of said rod. The shape of the rod contacting surface is adapted to the shape of the portion of the rod.

Abstract: Described is a rod insertion instrument for the insertion of a fixation rod in the tulips of adjacent pedicle screws in the context of a dorsal spinal column stabilization. It has a grip portion, a tube section adjoining it and a gripping head carried by the tube section, in which gripping head the fixation rod is rotationally fixedly and angularly stably receivable with its proximal end. In order to minimize accidental tissue compression during the fixing of the fixation rod into the pedicle screws, the gripping head is attached to the tube section exclusively via a lockable joint with which there is enabled an unconstrained pivoting movement of the tube section toward the fixation rod during the process of fixing the fixation rod to the pedicle screw.

Abstract: A spinal fixation system comprising a bone screw, a body, and a pressure cap. The bone screw may comprise a head at a proximal end and a bone connection element at a distal end. The body may comprise a proximal end, a distal end, a mounting rod receiving channel at the proximal end and a bone screw head receiving channel at the distal end. A proximal end of the pressure cap may comprise two side walls disposed apart from each other and one biasing member on each side wall. A distal end of the pressure cap may comprise a surface operable to contact at least a portion of the head of the bone screw. The pressure cap may be operable to exert pressure on the bone screw when a mounting rod is biased against the proximal end of the pressure cap.

Abstract: A bone anchoring device includes an anchoring element including a shaft and a head; a receiving part including a first end and a second end, and having a channel for receiving a rod near the first end, and an accommodation space for accommodating the head near the second end; and a pressure element configured to be located at least partially in the accommodation space and including a flexible portion to clamp the head, wherein the anchoring element is pivotable, and the pressure element is movable inside the accommodation space to lock the head within the pressure element, and wherein a first securing portion on the pressure element and a second securing portion on the receiving part are configured to engage and form a rigid coupling therebetween to prevent removal of the pressure element from the first end of the receiving part.

Abstract: 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.

Abstract: A closed-head polyaxial screw for use in spinal instrumentation for spinal fusion, treatment of deformity, or the like. Polyaxial screws may have a two-part design, with the screw fitting into an aperture in the closed head. One or more clamps may secure the bone screw in the aperture. A closed-head polyaxial screw having a one part design is also disclosed. In addition, a one-part monaxial screw is described.

Abstract: An osseous anchorage implant comprising an attachment structure adapted to receive and be attached to at least one bar, that is suitably an element of an osteosynthesis. The implant is made up of an osseous anchor and an attachment head bearing the attachment means. The attachment head is suitably traversed by a channel that is adapted to receive the bar. The attachment head comprises a clamp that is adapted to clamp the bar against an inside support wall of the channel. The implant is further characterized by the attachment means and the support wall enabling the rotation of the bar about a first axis that is not parallel to the longitudinal axis of the bar. The clamp comprises a moving clamping face, that is adapted to contact the bar, and that is borne by a support head that is articulatable at the end of the clamp via a ball and socket connection. The channel is suitably an open channel having an aperture opening onto one of the lateral faces of the attachment head, wherein the aperture bears the clamp.

Abstract: A locking assembly for securing a rod in a polyaxial bone anchoring device includes a first locking element having a first end, a second end, an outer surface with an external advancement structure, an inner wall, an internal advancement structure on the inner wall, and an engagement portion for a tool, and a second locking element having a first end configured to be oriented towards the first end of the first locking element, an opposite second end, an outer surface with an external advancement structure configured to cooperate with the internal advancement structure of the first locking element, and a portion at the second end having a width greater than a greatest width of the external advancement structure of the second locking element, wherein the second locking element is configured to move axially relative to the bone anchoring device at a speed different than the first locking element.

Abstract: The present invention generally is directed toward a spinal fixation system whereby a coupling element allows the physician to selectively lock or unlock either the connection between the coupling element and a fastener, such as to allow for repositioning of the coupling element, or the connection between the coupling element and an elongate rod. The locking or unlocking of these connections may be made independently and as desired by the physician.

Abstract: A tool set for implanting a rod in a human spine in conjunction with bone screws includes a pair of end guide tools that receive opposite ends of the rod in channels and under manipulation by a surgeon facilitate transport of the rod toward the bone screws attached to the guide tools. Each end guide tool includes a laterally extending, rigid, rod holding structure located near a bottom surface thereof. Intermediate guide tools having pass-through slots are utilized to guide the rod to the bone screws at intermediate locations. For bone screw implantation, the end guide tools and intermediate guide tools are assembled with a driver. The driver is coaxial with the respective guide tool and rotatingly mateable thereto. The driver includes a stem and a nut-type fastener, the stem receivable in the guide tool. The fastener allows for rotation of the bone screw without rotating the attached guide tool.

Abstract: A bone anchor assembly includes a bone anchor having a proximal head and a distal shaft configured to engage bone, a receiver member for receiving a spinal fixation element to be coupled to the bone anchor, an insert positioned in the proximal end of the receiver member having a pair of spaced apart insert arms defining a recess therebetween, and a closure mechanism positionable between and engaging the insert arms to capture a spinal fixation element within the recess of the insert and fix the spinal fixation element with respect to the receiver member.

Abstract: A surgical screw assembly including: a fastener including an elongate shaft having a proximal end and a distal end and a head at the proximal end. A tulip having a an internal bearing surface is provided. A distal end of the tulip has a bore therethrough defining the internal bearing surface. Locking enhancement features are configured to cooperate with the head, such that, in an unlocked configuration, the head is movable relative to the tulip; in a provisionally locked configuration, the locking enhancement features engage the head with a first polyaxial grip strength; and in a finally locked configuration, the locking enhancement features engage the head with a second polyaxial grip strength greater than the first polyaxial grip strength.

Abstract: The present invention generally is directed toward a spinal fixation system whereby a coupling element allows the physician to selectively lock or unlock either the connection between the coupling element and a fastener, such as to allow for repositioning of the coupling element, or the connection between the coupling element and an elongate rod. The locking or unlocking of these connections may be made independently and as desired by the physician.

Abstract: A pedicle screw fixation system and method for use of the same are disclosed. In one embodiment, a tulip is provided for holding a head of a pedicle screw substantially along a longitudinal axis. The tulip includes opposing first and second U-shaped receiving slots aligned along a transverse axis. A rod is received by the opposing first and second U-shaped receiving slots. A coupling collar includes a plurality of resilient fingers circumferentially disposed therearound such that a snap fit engagement with the head of the pedicle screw formed. The coupling collar includes a first deformable face operable for contact with the rod. A set screw is for adapted for driving engagement through the tulip along the longitudinal axis such that a second deformable face is positioned for contact with the rod. The first and second deformable faces conform to the shape of the rod in response to forceful engagement therewith.

Abstract: Pedicle screws that can include a pedicle screw body, housing, plurality of clamps, rod, and set screw are disclosed herein. The clamps may be positioned side by side inside the lower portion of the housing. When the rod and set screw are provided in the housing, the set screw applies a force on the rod and the rod engages the plurality of clamps, causing the clamps to frictionally engage a head of the pedicle screw between the clamps.

Abstract: Embodiments of the present invention are directed toward a system of apparatuses to correct spinal deformities along with associated surgical techniques. The apparatuses comprise passages or channels in which spinal rods of differing diameters may be secured to allow a surgeon to vary the diameter of rods used along the length of the spine. Additionally, embodiments of the present invention are directed toward instrumentation for reduction of spinal rods into spinal pedicle screws.

Abstract: The present teachings provide one or more surgical implements for repairing damaged tissue, such as in the case of a spinal fixation procedure. A bone anchor is provided. The anchor can include a bone fastener. The bone fastener can include a head and a second end adapted to engage an anatomy. The bone fastener can extend along a longitudinal axis. The anchor can also include a coupling arrangement coupled to the head of the bone fastener so that the bone fastener is rotatable about the longitudinal axis to define a first plane of motion. The anchor can further include a saddle, which can be coupled to the coupling arrangement. The saddle can be movable relative to at least one of the bone fastener and the coupling arrangement to define a second plane of motion.

Abstract: A spinal rod connector assembly for use with a vertebral bone screw has an articulating clamp for 1) fixing an orientation of the spinal rod connector assembly relative to and on the vertebral bone screw, and 2) attaching a separate spinal rod onto the spinal rod connector assembly in concert with one another. The articulating clamp resides in a body of the spinal rod connector assembly and transfers a received downward force laterally to a spinal rod component of the spinal rod connector assembly which is configured to abut the spinal rod and hold the spinal rod between itself and a spinal rod holder of the spinal rod connector assembly. The articulating clamp thus improves the force transfer efficacy of the system.

Abstract: A polyaxial bone screw assembly includes a threaded shank body having an upper capture structure, a head and a closed retainer ring. The external capture structure surface and retainer ring internal bore surface are both threaded for rotatable attachment within a cavity of the head. The head has a U-shaped cradle defining a channel for receiving a spinal fixation rod. The head channel communicates with the cavity and further with a restrictive opening that allows for loading the capture structure into the head but prevents passage of the closed retainer ring out of the head. The retainer ring has an external substantially spherical surface that mates with an internal surface of the head, providing a ball joint, enabling the head to be disposed at an angle relative to the shank body. The threaded capture structure or the closed retainer structure includes a tool engagement formation and gripping surfaces for non-slip engagement by a tool for driving the shank body into bone.

Abstract: Spinal anchoring methods and devices are provided that are effective to correct spinal deformities while allowing some flexibility to the spinal. In particular, the methods and devices allow a spinal fixation element to mate to several adjacent vertebrae to maintain the vertebrae at a fixed distance relative to one another, yet to allow the orientation of each vertebrae relative to the fixation element to adjust as the orientation of the patient's spine changes.

Abstract: The present invention is directed to a spinal implant system that incorporates unique snap, or spring loaded, features to assist the surgeon in the placement of screws, rods, hooks and transverse connectors. The poly-axial movement also uses a more direct loading lower saddle into the bone screw to improve locking of the construct.

Abstract: Devices and methods for enhancing the effectiveness of spinal stabilization, and particularly that of cervical spinal stabilization, are provided herein. More specifically, methods and systems are disclosed for effectively positioning occipital plates and spinal fixation assemblies within target vertebrae, while also reducing any associated patient trauma (e.g., muscle stripping, tissue damage, etc.). The systems and methods can utilize trans-lamina delivery of the spinal fixation assemblies to allow for the positioning of the fixation elements along the midline of the patient's spine.

Abstract: An apparatus (10) includes a fastener (16) engageable with a bone portion to connect a longitudinal member (12) to the bone portion. A housing (40) has a first passage (42) configured to receive the longitudinal member (12) and a second passage (44) extending transverse to the first passage. The fastener (16) extends through an opening (50) in the housing (40) into the second passage (44). A longitudinal axis (18) of the fastener (16) is positionable in any one of a plurality of angular positions relative to a longitudinal axis (46) of the second passage (44). A spacer (60) received in the second passage (44) of the housing (40) is engageable with the fastener (16) and the longitudinal member (12). A member (70) applies a force to prevent relative movement between the fastener (16) and the housing (40) and permit manual movement of the fastener (16) relative to the housing (40) against the force when the longitudinal member (12) is disengaged from the spacer (60).

Abstract: An element with a shank (1) and a holding element (2) connected to it for connecting to a rod (100) is provided, wherein the holding element (2) has a recess (3) having a U-shaped cross-section for receiving the rod (100) with two legs (4, 5) open at one end (6) and an inner thread (7) on the open legs (4, 5) and a locking element (9) with an outer thread (8) which cooperates with the inner thread of the legs, wherein the inner thread (7) of the legs and the outer thread (8) of the locking element are constructed with a flat thread in which the two flanks (7a, 7b; 8a, 8b)) enclose an angle of 90° in each case with the screw axis (S, M). This prevents splaying of the open legs when the locking element is screwed in. The flat thread is easy to produce.

Abstract: A bone attachment device comprises an attachment collar having a hinged lid is disclosed. The bone attachment device may also comprise a bone fastener (such as a bone screw). A bone attachment device including an attachment collar and a spinal rod locking device is disclosed. A bone attachment device as described herein may be used together with a spinal stabilization rod and one or more additional bone attachment devices. Such devices are adapted to clamp and hold a spinal stabilization rod. Methods for implanting a spinal stabilizer having a bone attachment device including a hinged lid are disclosed.

Abstract: The present invention is generally directed to orthopedic fixation devices that comprise a coupling element and a bone fastener, whereby the bone fastener can be loaded into the coupling element through the bottom of a bore in the coupling element.

Abstract: A polyaxial pedicle screw includes a housing, a bone screw member, and an anvil. The bone screw member includes a head and a threaded shaft extending from the head. The head is selectively securable within the housing. The anvil is positionable within the housing adjacent to the head of the bone screw member when the anvil and the head of the bone screw member are positioned within the housing. The anvil may define one or more grooves in an outer surface of the anvil. The groove defines a flap that is flexibly attached to the anvil to enable the anvil to flex an amount sufficient to maintain the head of the bone screw in constant contact with the anvil when the bone screw member is moved relative to the anvil.

Abstract: A bone anchoring device includes an anchoring element having a head, a receiving portion having a first region adjacent to a second end for receiving the head and a recess which is open towards a first end to form two free legs for receiving a rod. The anchoring device further includes a pressure element configured to couple to the head, a first closure element and a second closure element. The first closure element cooperates with the legs to simultaneously fix the rod in the recess and fix the head in the receiving portion, and the second closure element cooperates with the legs, the second closure element acts on the pressure element and on the rod to independently fix the head in the receiving portion and fix the rod in the recess. The first closure element and the second closure element are interchangeable.