Abstract: An orthopedic fixation device for affixing the screw head of a polyaxial pedicle screw has a tulip, a saddle, and a ring. The tulip has an interior cavity and two opposed threaded arms and a lower ledge. The saddle is inserted into the tulip body, and has a U shaped groove for receiving a spinal fixation rod. The ring has a diameter that is smaller than the widest diameter of the screw head, and is formable into a diameter larger than the widest diameter of the screw head when the screw head is pushed into the ring. The ring has a connection portion that mates with a connection portion of the saddle. The screw head is clamped within the tulip body between the saddle and the ring when a cap is threaded between the tulip arms.

Abstract: A modular pedicle screw for spinal fixation. The pedicle screw includes a bone screw and a modular head assembly. The bone screw having a head and a shank, the head defining at least one groove. The modular head assembly includes a housing having a proximal end, a distal end and a throughbore extending along a longitudinal axis of the housing between the proximal and distal ends of the housing, and an anvil disposed within the throughbore. The modular head assembly includes at least one protrusion sized and shaped to be received by the at least one groove for restricting relative movement between the housing and the bone screw to a single plane.

Abstract: The present invention relates to a device and system for fixation of intra-articular and extra-articular fractures and non-unions of small bones and other small bone fragments, and more particularly to a threaded nail with a robust length and a trailing end with a cutting tip and longitudinal cutting flutes and a stepped diameter with cutting flutes at the transition point, and an optional cannulation along the central longitudinal axis of the nail.

Abstract: Systems and methods are described for treating distal radius fractures using a plating system. In an aspect, a distal radius plating system includes a volar plate body for interfacing with a volar side of a distal portion of a radius bone. The volar plate body has a volar head portion extending from the volar plate body and terminating at a distal edge, the volar head portion including a first set of apertures to receive fixation fasteners therethrough to fix to the radius bone. The distal radius plating system also includes a radial longitudinal portion extending from a radial edge of the volar plate body to interface with the radial styloid of the radius bone while the volar plate body is positioned on the volar side of the distal portion of the radius bone.

Abstract: An acetabular reconstruction prosthesis with a piling-cup system is provided, which includes an iliac posterior pile screw, an iliac anterior pile screw, a pubic pile screw, an ischial pile screw, abutments, a 3D (three-dimensional) printed porous titanium mesh cup, locking screws, nuts, and tail cap screws. Four pile screws are the iliac posterior pile screw facing posterior of the ilium, the iliac anterior pile screw facing iliac tubercle, the ischial pile screw running along ischium ramus, and the pubic pile screw running along pubic ramus. A stable prothesis support system is formed in the acetabular reconstruction prosthesis with a piling-cup system, which conforms to the biomechanical characteristics of physiological pelvis, reduces the risk of prosthesis loosening and dislocation, and improves long-term stability of the prosthesis through biological fixation.

Abstract: A coupling device for coupling a rod to a bone anchor includes a receiving part having first and second ends, a central axis, and two legs defining a recess at the first end for receiving the rod, a pressure member configured to exert pressure on an inserted head, and an actuating member with an engagement surface configured to engage the pressure member. When a first portion of the actuating member moves axially in a first direction, the engagement surface is configured to move from a first axial position to a second axial position to adjust the pressure member from a non-locking position where the head is pivotable to a locking position where the head is locked. When a second portion of the actuating member moves in the first direction, the pressure member is adjusted from the locking position back to the non-locking position.

Abstract: A bone anchoring device includes a receiving part having a central axis, two legs defining a recess for receiving a rod, and a head receiving portion that is at least partially expandable and having an opening for inserting and pivotably holding a head of a bone anchoring element therein, and a locking ring mountable around the head receiving portion in an axial direction while a rotational orientation of the locking ring relative to the receiving part remains constant. When the locking ring is around the head receiving portion, the locking ring is rotatable around the central axis from a first rotational orientation to a second rotational orientation where a compressive force exerted by the locking ring on the head receiving portion is greater than at the first rotational orientation.

Abstract: An apparatus configured to lock an intrabody implant over a thread passing through the implant includes a lock body configured to advance to the implant over the thread and including at least one rotatable element, the lock body being configured to grip the thread proximally to the implant upon rotation of the rotatable element, and a rotation-maintaining element, configured to inhibit a reversal of the rotation of the rotatable element by engaging with the lock body. Other embodiments are also described.

Abstract: A modular pedicle screw assembly for immobilisation and stabilisation of spinal segments in a patient. One example of the modular pedicle screw assembly includes a bone screw, a uniaxial inner collet arranged to cooperate with a head of the bone screw, a seat arranged to provide seating for retention of the inner collet, and an inner collet actuator designed to engage the seat to activate the inner collet for clamping about the head of the bone screw.

Abstract: Implants, instruments, and methods are presented for fixing adjacent bone portions to promote fusion of the bone portion.

Abstract: An assembly for rectifying vertebrae, comprises: two bone anchoring means intended to be implanted on a same vertebra, a triangulation bar and a connection means for connecting the triangulation bar to each bone anchoring means and for holding the bone anchoring means in a given position in order to form, with the triangulation bar connected to the bone anchoring means by means of the connection means, a rigid triangular assembly, the triangulation bar comprising an attachment area for attaching a correction instrument arranged to ensure a rigid attachment in rotation and in translation of the correction instrument on the triangulation bar.

Abstract: A graft collar includes a body of cylindrical shape, including an upper surface and a spaced apart lower surface defining an outer wall and surface therebetween; an engagement section located on the upper surface of the body sized and shaped to engage a head of a bone fastener; an through hole extending axially through the body between the upper surface and the lower surface thereof, the through hole being sized to receive therethrough an elongate threaded shank extending from the head of the bone fastener, where the graft collar is formed from at least one of soft cadaveric allograft, hard cadaveric allograft, and synthetic bone void fillers.

Abstract: Orthopedic fixation devices, assemblies, and methods for securing a spinal rod. The orthopedic fixation device may include a tulip head with one or more internal components configured to secure a bone fastener. The tulip head may house a breakable shear clip that has an initial solid form. When the bone fastener is loaded into the tulip head, the shear clip breaks forming a split ring that expands radially outward to accept the screw head. Then, the shear clip collapses around the screw head, thereby securing the bone fastener to the tulip head. A spinal rod may be secured in the tulip head, for example, with a locking cap.

Abstract: Devices and methods for tissue and graft procedures are provided that are designed to fail under a certain amount of force, providing sensory feedback that a particular activity may be providing too much stress on a surgical implant. For example, a surgical implant can include a sacrificial element in the form of a filament designed to break when a certain threshold value of force is met or exceeded, while a second filament that has the ability to withstand higher values of force, is able to maintain the repair after the first filament fails. In other embodiments, the sacrificial element includes a filament engagement mechanism associated with a suture anchor configured to fail at a threshold value of force, and a second filament engagement mechanism of the anchor can maintain the repair after the first one fails. Many implants configurations are provided, as are various surgical methods incorporating sacrificial elements.

Abstract: A receiver assembly includes a receiver having a first channel, a through-space with internal recesses beneath a guide and advancement structure, and internal ridges projecting inwardly below the internal recesses. The assembly also includes an insert having a second channel, side structures protruding laterally outward below top surfaces, and opposed lower extensions extending downwardly below the second channel, with the insert being loadable into the through-space with the second channel in non-alignment with the first channel. The insert is the non-threadably rotatable within the through-space to align the second channel with the first channel and to move the side structures into the internal recesses above the internal ridges, with a subsequent forced downward displacement of the insert within the through-space causing the side structures to frictionally engage the internal ridges to inhibit the insert from moving upward within the through-space.

Abstract: A device for attaching a soft tissue graft to bone includes a body with a smooth contoured first surface and a second surface opposite the first surface having a plurality of outwardly extending fixation members. The second surface is at least partially formed of a porous material adapted for bone ingrowth. A channel extends at least partially through the body in between the first and second surfaces for receiving a portion of the graft. The channel is at least partially formed of a porous material adapted for tissue ingrowth, bone ingrowth or a combination thereof.

Abstract: A bone fastener system can comprise a fastener and a first sizing component. The fastener can comprise a shaft that provides an anchoring footprint. The first sizing component can be configured to be connected to the shaft and can include a first anchoring feature, or circumferential bone engaging feature, to increase a size of the anchoring footprint. The first anchoring feature can comprise a sleeve that radially expands a diameter of the threaded shaft. The first anchoring feature can comprise axially extending teeth. The system can further comprise a second sizing component including a second anchoring feature to increase the size of the anchoring footprint, the second anchoring feature being different from the first anchoring feature. The second anchoring feature can expand the diameter of the threaded shaft a greater amount than the first anchoring feature. The second anchoring feature can have a length greater than the first anchoring feature.

Abstract: A modular medical implant allowing the targeted injection of a liquid or pasty material into a bone cavity. This implant is produced with four types of modules provided with a lumen and of variable lengths, including: either a male securing principle, referred to as proximal modules, or a female securing principle, referred to as distal modules, or a male securing principle and a female securing principle, referred to as intermediate modules and perforated intermediate modules, that can be secured in a predetermined order and number in order to position the perforated intermediate modules at suitable levels to allow an injection product to be conveyed to and diffused at the targeted locations, via the perforations, while producing the required length of the implant. The implant is intended, in general, for surgical operations and, in particular, for interventional radiology.

Abstract: A device, method, and system for treatment or fixation of a fractured, damaged, or deteriorating bone or bones in a mid-foot region. The device comprising an implant with both proximal and distal fastener holes, along with fastener slots in a central elongated body, for securing the implant to the appropriate osseous cortical structures of the foot. The method for treatment or fixation of fractured, damaged, or deteriorating bones in the medial column of the foot with use of a device such as an intramedullary nail that attaches to either the talus or first metatarsal bones to secure the medial cuneiform and navicular bones in place.

Abstract: A bone graft delivery kit includes a hollow tube having a proximal end and a distal end. The hollow tube is configured to convey graft material to a graft receiving area in a patient. The hollow tube can be connected to an implant. The kit further includes a plunger to facilitate moving the graft material through the hollow tube.

Abstract: A “vascular-safe” pedicle screw and extension-ready spinal support system. The pedicle screw includes a self-tapping flute that recessed into a threaded shaft to define terminations of the threads at a face of said self-tapping flute. The terminations are curved to define a convex profile that extends from a root to a crest of the threads at said face of said self-tapping flute. The curved terminations tend to push soft tissue aside as opposed to slicing or tearing through the soft tissue, so that the self-tapping flute is less likely to slice into vascular vessels. The distal portion of the pedicle screw may also include depressions that reduce the circumferential contact area of the pedicle screw in the direction of rotation, which increases the applied pressure to the soft tissue for a given applied rotational force. The increased pressure augments penetration of the pedicle screw through tissue without resort to sharp cutting edges.

Abstract: A bone fixation clamp includes a first clamp assembly, a second clamp assembly, an inner locking member, and an outer locking assembly. The first and second clamp assemblies are transitionable between open and closed configurations. The inner locking member is transitionable between a locked position and an unlocked position. In the locked position the inner locking member engages the first clamp assembly substantially preventing the first clamp assembly from transitioning from the closed configuration to the open configuration. The outer locking assembly is transitionable between a locked position and an unlocked position. In the locked position the outer locking assembly engages the first clamp assembly and the second clamp assembly substantially preventing both the first clamp assembly from transitioning from the closed configuration to the open configuration and the second clamp assembly from transitioning from the closed configuration to the open configuration.

Abstract: The present invention relates to stable fixation of spine segments, allowing for fusion in, e.g., skeletally mature patients. More particularly, the invention relates to a bone fixation device that can be affixed to vertebrae of a spine to provide reduction (or enlargement) capabilities and allow for fixation in the treatment of various conditions, including, e.g., spondyloslisthesis, degenerative disc disease, fracture, dislocation, spinal tumor, failed previous fusion, and the like, in the spine. The invention also relates to a method for delivering and implanting the bone fixation device.

Abstract: A coupling assembly for coupling a rod to a bone anchoring element includes a receiving part having a first end, a second end, a recess having a bottom for receiving the rod, and an accommodation space having an opening at the second end of the receiving part for accommodating a head of the bone anchoring element, and a retainer element configured to be inserted into the receiving part from the first end and to hold at least part of the head, the retainer element having a first portion and a spring portion compressible in an axial direction attached to the first portion. When the retainer element is in the accommodation space in a first position, the spring portion extends in the axial direction from the first portion of the retainer element to an axial position between the first end of the receiving part and the bottom of the recess.

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. A rod reducer may be secured to the polyaxial pedicle screw to secure a spinal rod within the housing.

Abstract: A method of treating one of fractures and disfunctions of a pelvic ring of a patient comprising scanning a patient with a transdermal scan, determining, via a machine, from the scan an optimal range of angles of entry and sizes of screw to insert into the patient, communicating the optimal range to a surgeon, and inserting the screw into the patient.

Abstract: A graft or prosthetic element suitable, e.g., for replacing a tendon or ligament is fastened in a bone tunnel or blind opening with the aid of a fastener. In a first step, the graft or prosthetic element is press-fitted in the tunnel or opening by forcing the fastener into the opening or by positioning the fastener in the opening and then expanding it, wherein the fastener is in contact with the graft or prosthetic element and with the bone wall of the tunnel or blind opening. In a second step, the fastener is anchored in the bone wall of the tunnel or blind opening with the aid of a liquefiable material which is liquefied in the vicinity of the bone wall where it is in contact with the fastener and by making the liquefied material penetrate into the bone wall.

Abstract: A swivel suture anchor for knotless fixation of tissue. The suture anchor includes an anchor tip configured to capture suture, the anchor tip being rotatably received within a fixation device upon advancement of the fixation device over a shaft of the anchor tip. The anchor tip is configured to receive a suture to be anchor in bone without requiring suture knots. The anchor tip can be a conical metal tip which is self-punching and avoids the need for pre-drilling a hole in bone. The anchor tip includes a closed aperture to allow free sliding of a suture strand. The suture is secured in a hole in bone by inserting the anchor tip into bone, and advancing a fenestrated fixation device, such as a cannulated interference screw, over a shaft of the anchor tip.

Abstract: A fixation device includes a tapered cannula defining a bore therethrough, a shaft, and a post. The shaft includes a proximal portion disposed within the bore, and central and distal portions extending distally from the tapered cannula. The proximal portion includes a threaded inner surface defined therein. The shaft includes blades disposed within the central portion, the blades movable between a closed position in which the blades are disposed within the shaft and an open position in which the blades extend laterally through the shaft. The post includes a threaded outer surface threadingly engaged with the threaded inner surface of the shaft. The post is movable longitudinally within the shaft to transition the blades between the closed and open positions.

Abstract: A bone fixation system includes a length of suture, a screw, a tensioning tab, and an anchor. The length of suture has a first end and a second end. The screw comprises an elongated shaft having a threaded external surface, wherein the screw has a distal end, a proximal end, and an internal surface defining a passageway within the screw extending between the distal end and the proximal end, wherein the passageway is configured to receive the length of suture. The tensioning tab is affixed to a section of the length of suture. The anchor is configured to secure the first end of the length of suture adjacent to the proximal end of the screw.

Abstract: The disclosure relates to methods for attaching a dental implant surgical guide and a dental implant to a dental surgical site including: assembling an implant combination, positioning the dental implant surgical guide including a double open-ended guide cylinder at the dental surgical site; rotating the implant combination through the double open-ended guide channel; and attaching a cap comprising a hollow cylinder to the double open-ended guide channel so the rim of the implant mount body is sandwiched between the dental surgical guide and the cap. The disclosure further relates to a dental prosthesis apparatus including: an abutment; a dental implant; a dental implant surgical guide including a first and a second double open-ended guide cylinder connected by a support bar; an implant mount including a rim; and a cap operable to engage the dental implant surgical guide and sandwich the rim between the cap and the dental implant surgical guide.

Abstract: A system and method for osseous fixation is a surgical hardware device that allows bone fixation for purposes of fracture repair, arthrodesis, or other types of orthopedic applications. A partially threaded wire or pin is inserted into the bone and external compression and rotational stability are achieved with a locking cap. The locking cap may include serrations or other anti-rotation features which engage bone to provide rotational stability. Upon adequate bone healing, the external cap may be used to facilitate removal of the wire/pin from the bone.

Abstract: A pivotal bone anchor assembly includes a receiver with an axial bore communicating with a bottom of the receiver through a bottom opening, a circumferential locking groove adjacent the bottom opening, a circumferential expansion groove above the locking groove with a diameter that is greater than the diameter of the locking groove, and a transition surface between the locking groove and the expansion groove. The assembly also includes an insert uploadable through the bottom opening, an open retainer ring uploadable through the bottom opening after the insert and positionable within the locking groove, and a shank having a shank head.

Abstract: A suture anchor comprises a tubular body having an axial bore therethrough and having one or more purchase enhancements on an exterior surface of the body adapted to enhance purchase of the body within a bone hole, such as threads. A lateral port passes through the body from the bore to the exterior surface. A length of suture for attaching soft tissue to bone passes down along the exterior surface over the one or more purchase enhancements, over a distal end of the body, up into the bore through and then back out of the bore and up along the exterior surface over the one or more purchase enhancements.

Abstract: Implants, systems and related methods for correcting bunions are disclosed. The implants, systems and methods may include a first bone engaging implant configured to couple to a first bone, and a second bone engaging implant configured to couple to a second bone that is adjacent the first bone. The implants, systems and methods may further include a flexible cable member extending between the first and second implants that allows motion between the first and second implants but for movement of the first and second implants away from each other. The length of the cable member may draw the first bone towards the second bone and decrease an angle formed between therebetween. The cable member may be rigidly or slidably coupled to the first and second implants.

Abstract: Devices and methods for tissue and graft procedures are provided that are designed to fail under a certain amount of force, providing sensory feedback that a particular activity may be providing too much stress on a surgical implant. For example, a surgical implant can include a sacrificial element in the form of a filament designed to break when a certain threshold value of force is met or exceeded, while a second filament that has the ability to withstand higher values of force, is able to maintain the repair after the first filament fails. In other embodiments, the sacrificial element includes a filament engagement mechanism associated with a suture anchor configured to fail at a threshold value of force, and a second filament engagement mechanism of the anchor can maintain the repair after the first one fails. Many implants configurations are provided, as are various surgical methods incorporating sacrificial elements.

Abstract: A dynamic bone anchor includes an anchor member having first and second ends and a tubular section between the ends, a longitudinal axis extending from the first to second end, an outer surface, and a bone engagement structure for engaging a bone on at least a portion of the outer surface; and a longitudinal core member having a first portion and a second portion configured to be received in the tubular section and to connected to the anchor member, with the first portion configured to be spaced apart from the anchor member and movable with respect to it. The core member is made at least partially of a nickel-titanium (Ni—Ti) based shape memory alloy such that its shape after transitioning from a martensitic to austenitic phase is configured to result in a press-fit connection between the second portion and the anchor member with the second portion in the austenitic phase.

Abstract: A polyaxial bone anchor with a receiver, a shank, a pressure insert, a retainer for holding the shank in the receiver, and a closure. The receiver having at least one vertically aligned guide on a surface of an interior shank and insert receiving chamber. The insert having at least one shoulder that aligns with the guide and both properly positions the insert relative to the receiver during assembly and prevents the insert from axially rotating relative to the receiver.

Abstract: A method of repairing a pars fracture includes docking a needle guide on a lamina of the pars, inserting a needle at least partially through the needle guide, inserting a stylet at least partially through the needle, inserting a guidewire at least partially through the needle, removing the needle from the needle guide, removing the needle guide, positioning a screw assembly in contact with the lamina and co-axially with the guidewire, rotating an elongated portion of the screw assembly with respect to the lamina to move the screw assembly distally with respect to the lamina such that a distal end of the elongated portion of the screw assembly travels through an interior portion of the pars and into a superior portion of the pars, and approximating the distal end of the elongated portion of the screw assembly and a collar of the screw assembly to approximate the interior portion of the pars and the superior portion of the pars.

Abstract: A polyaxial bone anchoring device includes a bone anchoring element having a head, a receiving part having a channel for receiving a rod and an accommodation space for pivotably holding the head, and a pressure member having a pressure exerting surface and a deformable portion with a free end. The deformable portion is adjustable from a first configuration where a first part of the deformable portion is supported at a first axial position relative to the receiving part while a second part of the deformable portion protrudes further radially into the channel than parts of the deformable portion positioned axially above the second part, to a second configuration where the second part of the deformable portion is deformed radially outwardly and the pressure exerting surface is shifted lower axially to exert pressure on the head while the first part of the deformable portion remains supported at the first axial position.

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 bone fastener assembly including a bone screw, a receiver, a crown, a first retaining ring, and a second retaining ring is provided. The crown is received in an interior cavity of the receiver, and the first retaining ring is provided to hold the crown in the receiver. At least a portion of a head portion is received in the interior cavity of the receiver, and the second retaining ring is provided to hold at least a portion of the head portion in the receiver. The crown, the first retaining ring, and/or the second retaining ring can be manufactured using a 3D printing process that provides a higher surface finish (Ra).

Abstract: Methods for temporarily fixing an orientation of a bone or bones. Methods of correcting a bunion deformity. Bone positioning devices. Methods of using a bone positioning device. Bone preparation guides. Methods of using a bone preparation guide.

Abstract: A surgical system for use in correcting hammer toe or otherwise straightening toes or fusing other bones to one another includes a male drill bit and a female drill bit, as well as an absorbable pin. The male and female drill bits are configured to define complementary features from opposed, or facing, ends of bones that are to be fused to one another. The male and female drill bits may also be configured to define channels through the lengths of the bones that are to be fused to one another, with the channels being configured to align and define a continuous channel through the bones when they are assembled. The absorbable pin, which may be absorbed by a subject's body over time, is configured to be positioned in the continuous channel, and may hold the bones in an assembled relationship before and while they fuse to one another.

Abstract: Arthroplasty implants replace an articulating surface of a bone joint such as bone joints of the foot, and is characterized by a three-component device comprising a bone screw, a button, and a cap. The button incorporates knurling on its distal end to fixate onto bone, a center hole, a spherical pocket to mate with the bone screw for stabilization, and a proximal retention structure to mate with the cap. The bone screw incorporates distal bone (cortical) threads or threading, a spherical head, and a drive structure used to insert the bone screw through the hole of the button and into the bone (e.g. a distal segment of the first metatarsal). The cap incorporates a distal mating structure that retains the cap onto the button, a proximal smooth spherical head that mates with the distal surface of the bone (e.g. a phalange bone), and a tang that prevents rotation after implantation.

Abstract: A polyaxial pedicle screw includes a screwed shaft section for anchoring the pedicle screw in a vertebra, on one axial end of which a shaft head is configured which is coupled in a rotating and/or pivoting manner as well as in a tensile-force transmitting manner to a receiving sleeve for a longitudinal support. The receiving sleeve has a fastening means for selective positional fastening of the receiving sleeve with respect to the shaft section, the fastening means at least consisting of an inlay/pin mounted in the receiving sleeve and acting on the shaft head, and a locking element acting on the inlay/pin. The inlay/pin is configured with attachment points or engagement elements, which are not covered or overlapped by the locking element, for the provisional introduction of a compressive force on the inlay/pin parallel to the locking element.

Abstract: A screw assembly for a spinal implant comprises a first unit including insertion holes and an inner space, a rod having a side whose outer circumference surface is positioned on the insertion holes of the first unit and another side whose outer circumference surface is positioned on insertion holes of another first unit positioned adjacent to the first unit, a second unit having an upper portion rotatably received in a lower portion of the inner space and a lower portion screwed to a vertebral body, a third unit screwed to an upper portion of the inner space to hold the rod, and a fourth unit positioned between the inner space and the upper portion of the second unit and including a pressure cap seated in the inner space.

Abstract: A polyaxial bone anchor with a receiver, a shank, a pressure insert, a retainer for holding the shank in the receiver, and a closure. The receiver having at least one vertically aligned guide on a surface of an interior shank and insert receiving chamber. The insert having at least one shoulder that aligns with the guide and both properly positions the insert relative to the receiver during assembly and prevents the insert from axially rotating relative to the receiver.

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: Various exemplary methods and devices are provided for fixing bone anchors to bone. In general, the methods and devices can allow for a bone anchor to be fixed to a bone at a desired angle to a receiver member. In an exemplary embodiment, a bone anchor assembly is provided that includes a bone anchor configured to engage bone, a receiver member that polyaxially seats a spherical head of the bone anchor, and a compression member seated within the receiver member, proximally of the head of the bone anchor. The compression member can have a distal end with gripping features thereon configured to create at least one line contact and/or one band contact with the head of the bone anchor, thus providing a firm grip on the head of the bone anchor and reducing a risk of slippage of the bone anchor with respect to the receiver member.