Abstract: A bone anchor assembly is provided, which may be used in cervical, thoracic, lumbar or sacral areas of the spine or other orthopedic locations. The anchor assembly includes a bone anchor, a receiver mounted to the bone anchor, a saddle within the receiver, and an engaging member. The receiver extends along a central longitudinal axis proximally away from the bone anchor. A rod or other elongated connecting element is received in a passage of the receiver in contact with the saddle, and the engaging member engages the connecting element against the saddle, which engages the saddle against the proximal head of the bone anchor in the receiver. The orientation of the saddle in the receiver is adjustable to correspond to the orientation of the connecting element relative to the central longitudinal axis of the receiver.

Abstract: A polyaxial bone screw assembly includes a threaded shank body having an upper portion with a capture structure thereon, a retaining and articulating structure, a compression structure and a receiver for holding the capture structure, retaining and articulating structure, compression structure and a rod. The receiver includes arms that define a channel for receiving the rod. The arms have inner surfaces with a discontinuous flange form thereon for mating with a cooperating continuous flange form of a closure structure for capturing the rod within the receiver. The shank capture structure and the retaining and articulating structure are threadably attached and secured to one another with a buttress stop. In operation, the compression structure is disposed within the receiver between the shank upper portion and a rod but presses only upon the retaining and articulating structure.

Abstract: A polyaxial screw assembly includes a pedicle screw, a coupling, an insert, and a housing. The pedicle screw includes a shank having a helical thread formed thereon and a head at one end. The coupling is positioned on top the pedicle screw and releasably engages portions of the head. The coupling and pedicle screw are positioned within a distal portion of the housing. The pedicle screw is slid through an opening in the insert and the insert is thread into the distal portion of the housing to retain the coupling and the pedicle screw within the housing. The pedicle screw is rotatable and pivotable relative to the housing. Compressing the coupling within the housing locks the pedicle screw in a desired orientation.

Abstract: A bone anchoring device, includes a receiving part for receiving a rod-shaped implant element, the receiving part having a first bore coaxial with a longitudinal axis and extending from a first end of the receiving part, and a recess extending from the first end to accomplish insertion of the rod-shaped implant element. The device further includes a bone screw having a threaded section for insertion into the bone and being fixed at or positionable at a second end of the receiving part and a fixation element provided to the first bore to fixate a rigid section of the rod-shaped implant element. The rigid section of the rod-shaped implant element has a first width, and the recess of the receiving part has a second width. The second width is larger than the first width, such that the recess may accommodate a stepped portion of the rod-shaped implant element that has an increased thickness.

Abstract: A screw for use in spinal surgery provided with a screw shaft and a screw head and at least one extension tab extending proximally from the screw head, the extension tab being defined relative to the screw head by a stress concentration feature. At a proximal end of the extension tab, the extension tab may be narrower in a circumferential direction than the extension tab at a distal portion thereof. A particular shape of stress concentration may be provided.

Abstract: A spinal fixation assembly and capless multi-axial screw system and method are shown. The assembly comprises a receiver having a rotary lock which in one embodiment includes a plurality of channels which urge and lock the elongated member to the screw using a bayonet type connection.

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 medical implant assembly includes a polyaxial bone anchor having a shank with an upper portion, a receiver, a retainer for holding the shank upper portion in the receiver, a lower compression insert with surfaces for closely receiving an elongate connecting member and a closure structure that may independently engage the lower compression insert to lock the shank with respect to the receiver while selectively not locking the elongate member. Projections or splines of the shank upper portion mate with holding pockets on the retainer. The bone anchor includes a shank upper surface exclusively engaging the lower compression insert that is spaced from the retainer, the retainer and shank being configured for polyaxial motion with respect to the receiver prior to locking.

Abstract: A lock indicator gauge is provided to provide an indication as to whether a bone screw construct is in a locked or an unlocked condition when the lock indicator gauge is operatively engaged with the bone screw construct. A plunger longitudinally disposed within a housing of the lock indicator gauge translates within the housing by a distance that corresponds to the relative positions of inner and outer housings of the bone screw construct, wherein the relative positions of the inner and outer housings is dependent on whether the bone screw construct is in a locked or an unlocked condition.

Abstract: System for positioning a component on a frame relative to a reference. It comprises a ball assembly (4), composed of a rod (6), a ball (8) fixed to the rod (6) and a ball joint clamping system (10, 12) mounted on the rod to fix the ball assembly relative to the component; a vee assembly composed of a rod (16), a vee (18) fixed to the rod (16) and a ball joint clamping system (20, 22) mounted on the rod to fix the vee assembly relative to the frame; an elastic connecting element (26) to keep the ball (8) in contact with the vee (18).

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 novel surgical screw is presented as a polyaxial, multiaxial, or monoaxial screw. The polyaxial screw allows versatile angulation between a bone anchor section and a screw body and allows the surgeon to attach a rod to the invention in a top-loading manner and manipulate the rod to accommodate a patient's body and the surgical goals. The screw uses a rod saddle to seat a rod, and permits the surgeon to sagitally manipulate the rod. After implantation of the screw and insertion of the rod, a locking screw is used to fix the angle and position of the rod and screw body.

Abstract: Disclosed are spinal fusion assemblies for use in skeletal systems. The assembly includes a coupling element that can be coupled to a fixation element, such as, for example, a screw with a head that removably mates with the coupling element. The coupling element and fixation element are configured to be coupled to an elongate stabilizer, such as a rod, that is positioned between a top and a bottom saddle. A compression member, such as a compression nut, is configured to mate with the coupling element and provides a compressive force to the top and bottom saddles to secure the elongate stabilizer therebetween. The top and bottom saddles are movably positioned within the coupling element such that they can gradually reposition and self-align into a secure engagement with the stabilizer as the compression member provides the compressive force.

Abstract: A polyaxial bone screw assembly includes a threaded shank body member having an upper portion with an internal drive and, alternatively, a laterally extending alignment rib or fin. The bone screw assembly also includes a lockable receiver coupling member, an open retainer ring member having a slit or gap and a compression insert member. An inset conical or cylindrical surface on the shank upper portion frictionally engages a similarly shaped inner surface of the retainer ring. The receiver includes a restrictive lower opening that allows for uploading the shank upper portion and compressed retainer ring into the receiver cavity, but prevents passage of the retainer ring out of the receiver once the ring inner surface engages the conical surface of the shank upper portion.

Abstract: A vertebral stabilization assembly for stabilizing a vertebral segment. The assembly includes a vertebral anchor, a first stabilization member, a second stabilization member, and a threaded fastener. A post of the first stabilization member is configured to be positioned in a first socket of the head portion of the vertebral anchor and a post of the second stabilization member is configured to be positioned in a second socket of the head portion of the vertebral anchor. The threaded fastener is configured to threadedly engage a threaded opening of the head portion such that when the threaded fastener is threaded into the threaded opening, the threaded fastener engages both the post of the first stabilization member and the post of the second stabilization member.

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: A spinal fixation system (1) for use in the fixation of a spine comprising: a coupling element (2) having a pair of opposed longitudinal apertures (17) through a wall (35) thereof; a longitudinal slot (8) in a coupling element (2) interior surface (3); a hole (13) through the bottom end (5) of the coupling element (2); and a securing element (18) dimensioned for insertion into the coupling element (2), the securing element (18) having an outwardly extending wing (26) dimensioned for riding in the coupling element slot (8), for preventing a rotation of the securing element (18) about a longitudinal axis (7) thereof.

Abstract: A locking mechanism for locking a rod in a screw and rod fixation assembly includes a cap having a sidewall and a locking element extending from at least a portion of the sidewall. Locking mechanism cooperates with a receiver component for a spinal fixation rod to lock the rod in the receiver without requiring application of torque. A method of locking a spinal fixation member in a receiver of a screw fixation assembly includes the steps of placing the spinal fixation member into a channel of a receiver, axially advancing a locking cap into the receiver toward the spinal fixation member without application of any torque, and securing the locking cap in a locked position above the spinal fixation member without application of any torque.

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 bone anchoring device includes a bone anchoring element having a shaft for anchoring in the bone and a head; and a receiving part for coupling a rod to the bone anchoring element. The receiving part includes a first portion with a first end and a second end and a U-shaped recess for receiving the rod, the recess extending from the first end in the direction of the second end thereby forming two free legs and a second portion at the side of the second end opposite to the first end for accommodating the head, the second portion having a free end and being flexible so as to allow introduction and clamping of the head. The bone anchoring device also includes a locking ring embracing the second portion. The head is locked by means of exerting pressure with the rod onto the locking ring resulting in compression of the second portion of the receiving part and wherein the locking ring is mounted to the receiving part from the free end of the second portion.

Abstract: An apparatus includes a fastener engageable with a bone portion to connect a longitudinal member to the bone portion. A housing has a first passage configured to receive the longitudinal member and a second passage extending transverse to the first passage. The fastener extends through an opening in the housing into the second passage. The second passage includes a plurality of frustoconical surfaces for engagement with the fastener.

Abstract: A stabilization system for implantation in a patient includes: a bone anchor including a head and a shaft, the shaft extending away from the head in a bone insertion direction and being operable for connection to a bone of the patient; and a tulip including: at least one channel having an opening for receiving an elongate member, the opening being oriented in a receiving direction having at least a component thereof substantially opposite to the bone insertion direction of the anchor, and (ii) a fastening mechanism operable to apply a tangential load on the elongate member to maintain the elongate member within the channel, wherein the tangential load is transverse to at least the receiving direction.

Abstract: A spinal fixation system includes an elongated rod sized to extend between at least two vertebrae and a number of anchor devices for anchoring the rod to the spine. The anchor devices include a bone engaging fastener having a head defining a spherical socket. A ball insert is configured to be placed within the socket and rotated so that a spherical surface of the ball insert is juxtaposed with the spherical surface of the socket. The insert has a first dimension less than the socket opening and a second dimension that upon rotation causes the insert to be captively retained in the socket. The anchor device further includes a yoke defining a yoke channel for receiving the rod and including a stem that is engaged to the ball insert when the insert is captured within the socket. A sleeve is disposed between the yoke channel and the fastener head for supporting the rod thereon. A set screw is threaded into the yoke channel for clamping the rod against the sleeve.

Abstract: A tulip-shaped rod-receiving member in a spinal rod system is provided with a transverse slot accessible from the top of the tulip member for placing the rod therein until the rod seats. A locking assembly includes a cap having inclined surfaces that cooperate with inclined surfaces on the rod-receiving member to lock and bias inwardly the rod-receiving member relative to the cap. A novel seating ring is provided for the bone screw to be supported in the tulip in a manner that maximizes support and optimizes axial alignment of forces.

Abstract: An osteosynthesis device is proposed, particularly for spinal support or correction, enabling easier and compact implantation, that can be particularly used in the case of implantation via the anterior approach, and a preassembly method for such a device. In various embodiments, the device comprises implants screwed into two vertebrae (0) and a plate (2) used to hold and displace the spine. In various embodiments, the plate (2) comprises on at least one of its ends at least one longitudinally elongated opening, the opening having firstly at least one part opening onto an edge of the plate, or one part of a sufficiently large size (s210b) to be able to be inserted without disassembly in the fixation means of an implant (1) already screwed into the spine when the fixation means are already assembled.

Abstract: A polyaxial bone screw includes a head member and a shank member. The shank has a capture end and an opposite threaded end for threaded insertion into a vertebra. The head has a U-shaped cradle for receiving a spinal fixation rod and a central bore for receiving the capture end of the shank. An expandible retainer ring with a radial split is snapped onto the capture end of the shank to retain it within the head. The retainer ring has a spherical outer surface which forms a ball joint with a spherical socket cavity within the head to enable the head to be angled relative to the shank. A threaded closure plug is tightened within the cradle to clamp the rod into engagement with a knurled dome on the capture end of the shank to secure the rod relative to the vertebra.

Abstract: Bone anchor assemblies having a large diameter for fixing a spinal connection element to bone and methods of assembly are described. The assembly includes a receiver member for receiving the spinal connection element, a bone-engaging shank for engaging bone, a retaining member for retaining the head of the shank within the receiver member and a locking member for locking the retaining member within the receiver member.

Abstract: Bone screw assemblies include longitudinal connecting members that provide for dynamic stabilization, some including non-uniform portions that are configured to flex, contract or expand. Composite longitudinal connecting members include longitudinal segments made from different materials having different flexibilities. Polyaxial bone screw assemblies include change-out receivers for cooperating with replacement longitudinal connecting members having a different flexibility. Bone screw shanks for cooperating with one or more open receivers include treatment or coating to provide biologically active interface with bone.

Abstract: A polyaxial bone anchor includes an anchor head, an anchor member, a bushing, a sleeve and a fastener. The anchor head has a longitudinal bore and an inner spherical surface on a lower portion. The bushing is received within the longitudinal bore adjacent the lower portion and includes an exterior spherical surface for interacting with the inner spherical surface in the anchor head, an internal space defining an inner spherical surface for mating with a spherical head portion of the anchor member and a slot. The inner spherical surface of the bushing has a spherical centerpoint and the exterior spherical surface of the bushing has a spherical centerpoint. The spherical centerpoint of the inner spherical surface is vertically displaced toward the bottom end relative to the spherical centerpoint of the exterior spherical surface. The sleeve is received within the longitudinal bore. The fastener is mountable to the anchor head.

Abstract: A polyaxial bone screw assembly includes a threaded shank body integral with an upper capture structure and a head having an inner cavity for receiving the capture structure. The capture structure is threaded and the head includes a threaded opening for rotatable assembly with the capture structure and eventual locking frictional engagement between the capture structure and the head.

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

Abstract: An orthopedic retaining system comprising at least one bone screw which has a head part and a threaded shaft pivotally mounted thereon is disclosed. A clamping element is mounted in the head part, which can be pressed against the threaded shaft from its upper side and, as a result, secure the threaded shaft relative to the head part. A retaining bar is arranged in a receptacle of the head part and extends essentially transversely to the threaded shaft. A clamping device is provided on the upper side of the head part, by means of which the clamping element and the retaining bar are pressed into the head part such that the threaded shaft and the retaining bar are secured in position relative to the head part. The clamping device comprises an elastically deformable pressure element which is displaced into a clamping position during actuation of the clamping device.

Abstract: Constitutes a pedicle screw (1), a rosette (3) that fixes the pedicle screw (1) to a tulip (6), a bar that constitutes the link with other devices and a locking cap (9) associated to the closing screw (11) that is threaded on the inside of the tulip (6) and fixes the position of the bar. The locking cap (9) incorporates protuberances (12) that fit on the tulip (6), guiding the set formed by the locking cap (9) and the closing screw (11) during the positioning and threading of the closing screw (11) on the tulip (6) pressing the bar (8) against the rosette (3). The outer face of the tulip (6) and the locking cap (9) present an essentially circular configuration that is interrupted by two opposite-facing flat indentations (13, 14) that contribute to reduce the width of the device in the axial direction of the bar (8).

Abstract: A dynamic stabilization, motion preservation spinal implant system includes an anchor system, a horizontal rod system and a vertical rod system. The systems are modular so that various constructs and configurations can be created and customized to a patient.

Abstract: An adaptive spinal rod is provided for connecting levels of an adaptive stabilization system to support the spine while providing for the preservation of spinal motion. Embodiments of the adaptive stabilization rod include a ball having an anchor system, a deflection system, a vertical rod system and a connection system. The deflection system provides adaptive stabilization and load-sharing. The adaptive spinal rod connects different levels of the construct in a multilevel construct. The adaptive spinal rod cooperates with the deflection system to further reduce stress exerted upon the bone anchors and spinal anatomy.

Abstract: A medical implant device has in one embodiment a receiver member for receiving an elongated member, a crown member, an anchor member and a retaining member. An embodiment of the receiver member has an axial opening, a transverse channel, a chamber including at least one substantially flat wall, and a groove. An embodiment of the crown member has at least one substantially flat side. An embodiment of the anchor member has a head with at least one substantially flat surface that may be parallel to the anchor member's longitudinal axis, and an anchoring portion. An embodiment of the retaining member is a substantially flat clip. The crown member and anchor member are inserted into the chamber, and the retaining member is inserted into the groove beneath them. The anchor member may be pivoted substantially in one plane with respect to the receiver member until locked.

Abstract: An intermediate element for a detachable, lockable, ball joint-like connection in a device for the dynamic fixation of bones has a longitudinal axis, an outer wall concentric with the longitudinal axis, and an inner wall forming a coaxial cavity. Either the outer wall or the inner wall comprises one of two contact zones that form the ball joint-like connection. The intermediate element is at least partly made of a super-elastic or visco-elastic material.

Abstract: A coupling assembly may include an anchor member, a receiver member, and a seat member. The receiver member may have an anchor member end that cooperates with the anchor member and may have an implant receiving aperture for receiving an implant. The seat member may be disposable within the receiver member between the anchor member and the implant receiving aperture. First and second rotation-limiting features may be engageable to limit rotation of the seat member relative to the receiver member.

Abstract: In one embodiment of the present invention a system for connecting a fastener element (e.g., a pedicle screw) relative to a rod for the purposes of vertebral fixation is provided. The system may permit multi-axial movement between the fastener element and the rod. Further, the system may permit the angular relationship between the fastener element and the rod to be held in a desired orientation. For the purposes of describing and claiming the present invention, the term “rod” is intended to refer to any elongated structure. Such an elongated structure may be solid or hollow and may have any desired cross-section (e.g., circular, oval, square, rectangular). Further, for the purposes of describing and claiming the present invention, the term “interference fit” is intended to refer to physical contact between two or more components.

Abstract: The present application is directed to multi-axial screw assemblies to connect a longitudinal member to a vertebral member. In one embodiment, the multi-axial screw assembly includes a screw comprising a threaded shank and an enlarged head. The assembly may also include a body with an upper channel sized to receive the longitudinal member, a lower chamber to receive the head. The body is constructed to maintain the head in the lower chamber.

Abstract: A spanning connector for connecting an offset bone anchor to a previously inserted spinal fixation element and method of use is provided. The spanning connector includes a first connecting mechanism for connecting the spanning connector to the bone anchor, and a second connecting mechanism for connector the spanning connector to the previously inserted spinal fixation element. The spanning connector also includes a connector body for coupling the first connecting mechanism and the second connecting mechanism. Embodiments of a spanning connector may also reduce a separation distance between the bone anchor and the spinal fixation element. Embodiments of a spanning connector are configured, sized and dimensioned for use in a minimally invasive surgical technique, such as a rod-first spinal surgical technique.

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

Abstract: The fixing apparatus includes a pressure fixing device to pressure fix a rod to a circular arc rod engagement portion, and small protruding portions that bite into the rod and have an acute angle in both end sides of the rod engagement portion outside of the pressure fixing device. A recess surface of the circular arc rod engagement portion between the small protruding portions is formed as a rough surface.

Abstract: Provided is a novel uni-planar taper lock screw for connecting a connecting rod to bone. The screw is capable of being secured to the underlying bone while the screw head adapted to securely hold a connecting rod is articulated in a uni-directional manner to facilitate a stable connection to the connecting rod. After the screw had been articulated and properly positioned, it can be partially locked such that the connecting rod will remain in relative position to the bone while permitting flexibility of the screw head relative to the bone along a single plane. The screw head can then be fully locked securing the connecting rod into a selected position. The screw is configured for easy insertion and connection as well as easy removal and disconnection from the connecting rod. Also provided is a system for fixing two or more bones or bone fragments and a kit for fixing bones or bone fragments. A method of fixing bones or bone fragments is also provided.

Abstract: A polyaxial bone screw assembly includes a threaded shank body having an upper capture structure, a head, a retaining ring and a nut. The external capture structure surface includes a threaded portion and a smooth portion; the smooth portion for slidably mating with the retaining ring and the threaded portion for rotatable attachment to the nut within a cavity of the head. The nut fixes the retaining ring to the shank and also provides a tool engagement formation for driving the shank body into bone.

Abstract: Methods and devices that utilize segmental fixation between several adjacent vertebrae, thus allowing each vertebrae to be adjusted independently, are provided. In general, the device includes a spinal anchoring element that is adapted to seat at least one spinal fixation element, and a closure mechanism that is adapted to mate to the spinal anchoring element to lock the at least one spinal fixation element in a fixed position relative to the spinal anchoring element.

Abstract: Stabilization systems for stabilizing one or more vertebral levels are provided. The systems include anchors engageable to the vertebrae and an elongate connecting member system that maintains distraction between the vertebrae while allowing at least limited vertebral motion of the stabilized vertebral levels. The stabilization systems can be employed alone in non-fusion procedure or in conjunction interbody fusion and/or postero-lateral fusion procedures. The connecting members are structured to maintain a constant or slightly variable distance between the anchors to which the connecting members are connected while the connections of the connecting members with the anchors allow motion.

Abstract: Embodiments of an orthopedic implant device and system, and methods for implanting them, are disclosed. The implant may include a receiver member having a channel for accommodating an elongated rod or other longitudinal member, a bone anchoring member such as a screw or hook, and a base member rotatable with respect to the receiver member for retaining the bone anchoring member in the receiver member. The base member is configured to allow at least two different degrees of maximum angulation of the bone anchoring member with respect to the receiver member. The number and relative direction of such angulations are independent of the orientation of the channel or other part of the receiving member.

Abstract: A bone stabilizing system includes a collar that has a tubular sidewall with an interior surface and an exterior surface each extending between a first end and an opposing second end, the interior surface at least partially bounding a longitudinal passage extending therethrough. The collar also includes a pair of opposing spaced apart channels transversely extending through the sidewall at the first end thereof and a pair of spaced apart bayonet prongs projecting from the first end of the tubular sidewall. A screw has a threaded portion and a head disposed on an end thereof, the head of the screw being disposed within the longitudinal passage of the collar. A locking cap has a hole extending therethrough and a pair of spaced apart bayonet slots formed thereon, the bayonet slots being configured to receive and engage with the pair of bayonet prongs.

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