Abstract: An anchor assembly for use in spinal fixation to interconnect a longitudinal spinal rod, which is integrally formed with a body of the anchor assembly. The anchor assembly includes a bone anchor, a collet, a body portion, a rod portion, and a locking cap. The anchor assembly is preferably configured so that in use, the bone anchor may be secured to the patient's vertebra prior to being received within the body portion. The anchor assembly enables a surgeon to implant the bone anchor without the body portion to maximize visibility and access around the anchoring site. Once the bone anchor has been secured to the patient's vertebra, the rod portion may be inserted into the rod-receiving channel of a second bone fixation element having a rod-receiving channel implanted at a second site and the body portion can be snapped-onto the bone anchor.

Abstract: Screw and rod systems include polyaxial and hinge joints which provide independent first and second ranges of motion. The first and second ranges of motion are additive in a direction along the rod, so that the screw has greater angulation relative to the rod along the rod than transverse to the rod.

Abstract: A receiver for engaging a bone stabilizing element includes a receiver portion connectable to the stabilizing element, and a base portion connectable to a bone of a patient. The base portion may connect to the bone with a bone screw, for example a polyaxial bone screw, and the receiver portion may connect to the stabilizing element, for example a rod, using a set screw. The receiver portion and the base portion are slideably connected to each other, coupled and constrained in relative movement, by overlapping portions. Axial rotation between the receiver portion and the base portion is enabled by changing the relative dimensions of overlapped portions.

Abstract: A pedicle screw assembly and method of assembly are disclosed. The pedicle screw assembly includes a bone fastener having a head at a proximal end and a threaded portion extending between the proximal end and a distal end. The assembly also includes a compression member having a conical inner surface and a locking member having an outer surface adapted to mate with the conical inner surface of the compression member. The assembly may also have an elongated member and a set screw that has a threaded portion. The assembly may also have a receiving housing having a central bore extending from a threaded proximal end to a distal end and a U-shaped cavity positioned perpendicular to the central bore and configured to receive the elongated member.

Abstract: A bone anchor includes an anchor member including a first material, and having a tubular section extending along a longitudinal axis, a region configured to expand radially outwards from the longitudinal axis, and a bone engagement structure projecting from at least a portion of the expandable region of the tubular section, and a core member including a second material, and configured for insertion into and connection to the anchor member. When the core member is in the anchor member and is actuated relative to the anchor member, the tubular section is adjustable between a first position where the expandable region of the tubular member has a first length and a first maximum diameter, to a second position where the expandable region of the tubular member has a length shorter than the first length and a maximum diameter greater than the first maximum diameter.

Abstract: A polyaxial bone screw assembly includes a threaded shank body having an upper portion, a receiver, a compression insert and an articulation structure made from at least two discrete pieces. The shank upper portion cooperates with the compression insert to place the retainer in frictional engagement with the receiver. The geometry of the retainer structure pieces corresponds and cooperates with the external geometry of the shank upper portion to frictionally envelope the retainer structure between the capture structure and an internal surface defining a cavity of the receiver.

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 bone anchor having a rod housing including a base that has an internal groove oriented at an angle oblique to the longitudinal axis of the base, a capture ring situated within the groove and oriented at an angle oblique to the longitudinal axis, and a bone fastener extending into the rod housing and including a fastener head situated within the base and having a surface that mates with the capture surface of the capture ring to maintain a connection between the bone fastener and the rod housing.

Abstract: A spinal implant system comprises a plurality of alternate first members. Each of the first members includes an inner surface defining an implant cavity. A second member is configured to penetrate tissue and includes a mating element engageable with a first member such that the second member is interchangeable with the plurality of first members. A first member is selected for connection with the second member to comprise a bone fastener having a selected movement. Fasteners, instruments and methods are disclosed.

Abstract: A polyaxial bone anchoring device is provided comprising a bone anchoring element having a shank to be anchored in a bone and a head; a receiving part coupled to the shank and configured to pivotably receive the head, and having a channel for receiving a rod and a longitudinal axis; a pressure member configured to be positioned in the receiving part; a locking member insertable into the channel; wherein the pressure member has a deformable portion; and wherein, when the locking member is advanced into the channel in the direction of the longitudinal axis, the locking member in moveable from a position where it contacts the pressure member resulting in a load applied to the pressure member that clamps the head, to a position where the locking member contacts the pressure member such that the deformable portion is deformed and the locking member contacts the rod and clamps the rod.

Abstract: Various methods, devices, and systems are disclosed that facilitate easier and more compact implantation of osteosynthesis devices. In some embodiments, implants are screwed into two vertebrae and a plate is used to hold and displace the spine. In some plate embodiments, at least one longitudinally elongated opening is disposed at one end of the plate and partially opening onto an edge of the plate. In some plate embodiments, at least one longitudinally elongated opening is disposed at one end of the plate having a portion sufficiently large to be inserted without disassembly in the fixation means of an implant already screwed into the spine when the fixation means are already assembled.

Abstract: An open implant closure structure includes a helically wound guide and advancement structure having at least two helically wound forms thereon providing a multi-start closing mechanism for use between spaced arms of a cooperating open medical implant having mating helically wound structure thereon. Illustrated structures include interlocking flange forms, v-threads, square threads, reverse angle threads and buttress threads and receivers with break-off extensions and cooperating tooling.

Abstract: 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.

Abstract: A spinal alignment system can include a rod and a plurality of uniplanar screw assemblies that include a screw, a cap, and a housing. The screw and cap can be configured such that the relative angular displacement between the screw and the cap is limited to a first limit angle in a first plane and to a second limit angle in a second plane that is perpendicular to the first plane, the second limit angle being larger than the first limit angle. The housing can be coupled to the cap and configured to maintain the cap in proximity with the head of the screw. The housing can have two elongated elements forming a U-shaped saddle. The alignment system can also include a plurality of locking cap assemblies that capture the rod within the U-shaped saddle and are tightened to fixedly couple the rod to the respective uniplanar screw assemblies.

Abstract: A coupling assembly for coupling a rod to a bone anchoring element, and including a receiving part having a first end, a second end, and an accommodation space having an opening at the second end for inserting a head of the bone anchoring element, a pressure element insertable from the first end, positionable in the accommodation space, and configured to hold the head, the pressure element having at least one spring portion extending circumferentially around the pressure element and being radially compressible, and a rod receiving element separable from the pressure element, wherein in a first position, the spring portion is configured to engage an engagement structure at an inner wall of the receiving part to prevent movement of the pressure element towards the first end, and wherein the rod receiving element is configured to move the pressure element from the first position towards the second end.

Abstract: A pivotal bone anchor assembly includes a shank sub-assembly comprising a shank and a coupler, and a receiver sub-assembly comprising a receiver having a bore with a bottom opening and a snap-fit assembly proximate the bottom opening comprising an insert, a retainer ring positioned within an expansion chamber, and a positioner configured to hold the retainer ring in position. The shank sub-assembly is uploaded through the receiver bottom opening such that the positioner is pushed up into a holder chamber and the retainer rings engages a circumferential locking groove of the coupler to secure the shank sub-assembly with the receiver sub-assembly with a snap-fit connection.

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: An anchoring system implantable in bone. The anchoring system includes a screw having a screw head, a screw shaft, a plurality of interface elements, each adjacent pair of the interface elements has an interface by-pass channel disposed therebetween, a boring ring that includes cutting teeth and a ring by-pass channel, and a coupling assembly that is adjustable with respect to a longitudinal axis of the screw.

Abstract: A separate nub component between the plate and an intervertebral fusion cage, wherein the nub is attached to the plate. The nub lessens the undesired pivotal movement of the plate. It is believed that when the nub fits snugly between the endplates of the adjacent vertebral bodies, it acts as a stop against the undesired pivotal movement of the plate.

Abstract: A coupling device is provided for coupling a rod to a bone anchoring element. The coupling device includes a receiving part having a first end, a second end, a central axis extending through the first end and the second end, and a channel for receiving a rod. The receiving part defines an accommodation space for accommodating a head of a bone anchoring element, the accommodation space having an opening for inserting the head. The coupling device further includes a pressure element arranged at least partially in the accommodation space, the pressure element having a flexible portion to clamp an inserted head, and a clamping element extending at least partially around the flexible portion of the pressure element. The clamping element is configured to move from a first position to a second position in which the clamping element exerts a clamping force onto the pressure element, where the movement includes rotating the clamping element around the central axis.

Abstract: An angled offset tulip has an angled offset tulip with a rod receiving portion and a bone screw receiving portion. The bone screw receiving portion has a distal opening on a distal end. The rod receiving portion is positioned offset a distance from a center of the distal opening and elevated above the distal opening to form an angle ?. The angle ? is defined as a line passing through the center of the distal opening and a slotted end center. The rod receiving portion has a slotted opening defined by a pair of sides, each side having a proximal end with threads for engaging a set screw to secure a rod. The angled offset tulip can be an angled offset tulip assembly having a collet for receiving, holding and fixing the head of a bone screw.

Abstract: A pedicle screw includes a tulip head, a rod seat, a screw shank, and a retainer collar. The tulip head has an upper opening disposed in a top end of the tulip head and a lower opening disposed in a bottom end of the tulip head opposite the upper opening. The upper and lower openings form a single cavity extending through the tulip head from a top end to the bottom end. The rod seat is disposed within the cavity of the tulip head and engages a stop extending inwardly from an interior wall of the cavity. The screw shank has a thread disposed along a length of the screw shank and a connector positioned at an upper end. The retainer collar has a pass through aperture, an expansion slit, and is disposed about the connector of the screw shank. Other embodiments are described and claimed.

Abstract: Patient-mounted retractors with varying configurations and/or features are provided, along with additional components for use therewith in provided patient-mounted retractor assemblies. Blade type and tube type patient-mounted retractors that may be re-positioned during the course of a procedure are provided in varying configurations and/or geometries suitable for varying procedures and/or patient anatomies. Applications of re-positionable patient-mounted retractor assemblies are particularly suitable for use in minimally invasive procedures, eliminating the need for table-mounted retraction assemblies and/or cannulas that restrict the operating environment.

Abstract: An internal bracing system is disclosed for stabilizing a joint such as the knee, shoulder, ankle or the like. The internal bracing system includes an extra-articular tension band mechanism and an anchor assembly therefore. The internal bracing system adds substantial control to unstable joints which is effective in limiting the pathological joint motions and internal slippage. The anchor anchoring assembly designed to affix a tethering device to various bony structures which form a joint, for the purpose of providing stability. The anchor assembly includes an anchor and a set screw. A series of disc structures compressed by the set screw securely holds the tether without binding.

Abstract: A receiver for engaging a bone stabilizing element includes a receiver portion connectable to the stabilizing element, and a base portion connectable to a bone of a patient. The base portion may connect to the bone with a bone screw, for example a polyaxial bone screw, and the receiver portion may connect to the stabilizing element, for example a rod, using a set screw. The receiver portion and the base portion are slideably connected to each other, coupled and constrained in relative movement, by overlapping portions. Axial rotation between the receiver portion and the base portion is enabled by changing the relative dimensions of overlapped portions.

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: A bone fastener comprises a first member including an inner surface defining an implant cavity and a wall defining a groove. A first element is disposed within the groove. A second member is configured to penetrate tissue and engageable with the first element to dispose the first element in a capture orientation within the groove to connect the members. A second element is engageable with the first element to urge the first element to the capture orientation. Systems, instruments and methods are disclosed.

Abstract: A polyaxial bone screw assembly includes a threaded shank body having an upper portion, a receiver, a compression insert and an articulation structure made from at least two discrete pieces. The shank upper portion cooperates with the compression insert to place the retainer in frictional engagement with the receiver. The geometry of the retainer structure pieces corresponds and cooperates with the external geometry of the shank upper portion to frictionally envelope the retainer structure between the capture structure and an internal surface defining a cavity of the receiver.

Abstract: A dental implant device for insertion into a bore defined in bone for use with a prosthetic tooth or dental appliance includes an abutment with a plurality of male keys disposed about the distal end of the abutment capable of being affixed to the prosthetic tooth or dental appliance, an implantable anchor having a proximal and distal end, a plurality of female keyways defined into the proximal end of the anchor, the keyways capable of coupling to the male keys of the abutment and thereby preventing relative rotation of the abutment and anchor; an interlocking thread helically defined around a longitudinal axis of the anchor, the thread being adapted to couple to the bore defined in the bone and means for coupling the abutment to the implant anchor.

Abstract: A separate nub component between the plate and an intervertebral fusion cage, wherein the nub is attached to the plate. The nub lessens the undesired pivotal movement of the plate. It is believed that when the nub fits snugly between the endplates of the adjacent vertebral bodies, it acts as a stop against the undesired pivotal movement of the plate.

Abstract: A separate nub component between the plate and an intervertebral fusion cage, wherein the nub is attached to the plate. The nub lessens the undesired pivotal movement of the plate. It is believed that when the nub fits snugly between the endplates of the adjacent vertebral bodies, it acts as a stop against the undesired pivotal movement of the plate.

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: A low profile orthopedic device is used to fix and stabilize bones to correct anomalies in skeletal structure occurring naturally or by trauma. Bone screws are screwed into bones by application of torque. Connectors are attached to the anchored bone screws. Each connector includes a clamp and a compression ring. A connecting rod connects several connectors together. The clamps are tightened to hold the rod to the bone screws in a pre-selected position by linear movement of the compression ring.

Abstract: A minimally invasive spinous process fixation system includes dual rigid spinous clamps, each configured to articulate axially along a cylindrical shaft, and together configured to enclose and clamp around the adjacent or superior spinous process by means of opposing and swiveling spherical contact heads with spiked spinous contact faces. The spinous clamps are lockable when desired compression is achieved. A pedicle clamp has right and left clamp bodies for enveloping pre-existing pedicle rods. Each of the right and left clamp bodies includes upper and lower rigid metal plates supporting medial and lateral swivel cups. The upper and lower medial swivel cups engage and clamp about a connecting rod extending from the spinous clamp, and the upper and lower lateral swivel cups engage and clamp about one of the pedicle rods. A channel through the upper and lower metal plates accepts a locking screw to simultaneously tighten and fix the swivel cups in place about the connecting rod and the pedicle rod.

Abstract: A bone fastener includes a first portion that defines a longitudinal axis and includes an inner surface defining an implant cavity. An intermediate portion includes a first part having a wall including a first end surface that defines at least a portion of the implant cavity and a second end surface. The intermediate portion further includes a second part having a wall including an end surface connected with the second end surface of the first part and an inner surface. The second part is rotatable relative to the first part. A second portion includes a first end engageable with the inner surface of the second part and a second end configured to penetrate tissue. Systems and methods are disclosed.

Abstract: A tulip bone screw assembly has a bone screw, a tulip and a saddle. The bone screw has a threaded shank and a polyaxial head. The tulip has a slotted opening for receiving a rod and an open distal end for passing the shank of the bone screw and holding the head and a locking ring positioned between the slotted opening and the distal end. The saddle has an axis defined by a center opening, a proximal concave end for engaging and holding the rod and a distal end with a plurality of friction fingers bent inwardly toward an axis of the saddle for applying a friction force to the head of the bone screw.

Abstract: A bone screw, which can be a pedicle screw, is generally tulip-shaped. A bore in the bottom of the tulip permits a threaded shaft to be partially inserted into the open interior of the tulip. A seat is formed on the threaded shaft and receives the bottom of the tulip, and prevents the threaded shaft from being inserted too far into the tulip. A saddle is positioned in the interior of the tulip and receives the end of the threaded shaft on one end and can include a trough on its opposite face which can receive a rod that connects together two or more such assemblies. A retaining screw threads into the upper interior surface of the tulip to hold the subcomponents together.

Abstract: The present disclosure relates, according to some embodiments, to translational pedicle screw systems. A translational pedicle screw system may comprise a bone screw secured within a saddle. Different mechanisms may provide for translational movement of the saddle relative to the bone screw. In some embodiments, a saddle may comprise an elongated distal channel configured to provide a translational motion of a bone screw head disposed therein. In some embodiments, a saddle may comprise a discoidal recess configured to receive a corresponding discoidal section of a bone screw. The discoidal recess and the discoidal section may allow for a rotational offset of the saddle relative to the bone screw. In some embodiments, a proximal portion of a bone screw may comprise an attachment section configured to engage with a removable bone screw head. The removable bone screw head may translate laterally along the attachment section of the bone screw.

Abstract: A bone anchor (100) for attaching a rod (108) to a bone has an anchor member (106) for attachment to the bone and an anchor head (104) having a U-shaped opening for receiving the rod. The bone anchor also includes a locking cap (102) that has a main body (900) and a set screw (1000). Advantageously, in one embodiment the locking cap preferably is designed such that a single tool can be used to lock the locking cap in place on the anchor body preferably with a 90° turn and preferably then drive the set screw to clamp the rod. The locking cap also preferably non-threadingly engages the anchor body. The anchor body preferably has an inclined surface on its top surface which elastically deflects extending tabs on the main body to secure the locking cap to the anchor body. A method of implantation and assembly of the bone anchor are also described.

Abstract: A minimally invasive spinal fixation system comprises first and second bone screws each including a threaded shaft for respective engagement with a vertebra and a yoke articulatingly attached to the shaft, each yoke including a pair of upstanding opposed arms defining a slot therebetween. A connecting element has opposite ends and a longitudinal axis extending therebetween, the connecting element including a tab adjacent each end projecting from the connecting element transversely to the longitudinal axis. Bone screw extensions are provided for guiding the placement of the connecting element into the yoke slots, each extension having a pair of opposing slots that are sized to pass the tabs through the extensions when oriented in a first position and to prevent passage when the tabs are oriented in a second different position.

Abstract: A modular head-to-head cross connector or construct extension system comprising a fastener element driven into a bone in a first orientation, a first U-shaped body operable to receive the fastener element and operable to receive a first rod in a first rod receiving channel, and a first compression element driven adjacent to and against the first rod in the first rod receiving channel, thereby engaging the first rod against the fastener element in a second orientation independent of the first orientation of the fastener element. The system further comprises a second U-shaped body operable to receive first compression element and operable to receive a second rod in a second rod receiving channel, and a second compression element driven adjacent to and against the second rod in the second rod receiving channel, thereby engaging the second rod against the first compression element in a third orientation independent of the second orientation.

Abstract: A device includes a display screen and a processor. The processor is configured to convert a textual document into sequentially ordered portions of text and display at the same designated location on the display screen the portions of text one at a time in the sequential order for a user to read.

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: The present invention is directed an anchor assembly for use in spinal fixation to interconnect a longitudinal spinal rod with a patient's vertebra. The anchor assembly preferably includes a bone anchor (10), a body (20) with a rod-receiving channel, an insert member (40) (preferably a bushing), and a locking cap with a saddle (70). The anchor assembly preferably enables in-situ assembly where the bone anchor may be secured to the patient's vertebra prior to being received within the body of the bone anchor assembly. Accordingly, the anchor assembly enables a surgeon to implant the bone anchor without the body to maximize visibility and access around the anchoring site. Once the bone anchor has been secured to the patient's vertebra, the body may be snapped onto the bone anchor and a spinal rod may be inserted into the rod-receiving channel.

Abstract: A receiving part for receiving a rod for coupling the rod to a bone anchoring element includes a receiving part body including a first end and a second end, and having a substantially U-shaped recess at the first end forming a channel for receiving the rod, and an accommodation space for accommodating a head of the bone anchoring element, the accommodation space having an opening at the second end for introducing the head; and a pressure element arranged at least partially in the accommodation space, the pressure element including a first section having a second recess for receiving the rod, and a second section having a flexible portion to clamp the head, the first section and the second section being fixed relative to each other, wherein said pressure element is insertable from the opening.

Abstract: 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.

Abstract: A polyaxial bone anchor including a housing, a bone screw, and a retainer for pivotably coupling the head of the bone screw to the housing. The retainer is positioned into the bore of the housing and includes a plurality of alternating tabs and slots circumferentially arranged to define a cavity for receiving the head portion of the bone screw therein. The retainer is axially moveable in the housing from a first position in which the head portion is not passable through the lower opening of the retainer to a second position in which the head portion is passable through the lower opening of the retainer.

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: A medical implant assembly includes a polyaxial bone anchor having a shank, a receiver, a lower compression insert with surfaces for closely receiving an elongate connecting member and a dual closure structure that may include a single flange or helical flange. The dual closure structure independently engages the connecting member and the lower compression insert. A threaded capture connection of the bone anchor includes a shank upper surface exclusively engaging the lower compression insert and a retainer threadably attached to the shank and spaced from the upper surface, the retainer configured for polyaxial motion with respect to the receiver prior to locking.

Abstract: A medical implant assembly includes a polyaxial bone anchor having a shank, a receiver, a lower compression insert with surfaces for closely receiving an elongate connecting member and a dual closure structure that may include a single flange or helical flange. The dual closure structure independently engages the connecting member and the lower compression insert. A threaded capture connection of the bone anchor includes a shank upper surface exclusively engaging the lower compression insert and a retainer threadably attached to the shank and spaced from the upper surface, the retainer configured for polyaxial motion with respect to the receiver prior to locking.