Abstract: Bone anchor assemblies and methods are provided having a multi-component bone anchor that is configured to allow the shank of the bone anchor to be bottom loaded into a receiver member. In one embodiment, a bone anchor assembly is provided having a shank with a distal threaded portion and a proximal head portion, a ball having a spherical exterior surface and a central lumen sized to receive the head portion of the shank, and a clip configured to be engaged between the head portion and the ball such that the clip is effective to lock the ball in engagement with the shank.

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 surface of the bone. In an exemplary embodiment, a bone anchor assembly is provided that includes a bone anchor configured to engage bone, a receiver member for seating a head of the bone anchor, and a compression member for securing the bone anchor at fixed angle with respect to the receiver member when the compression member is seated within the receiver member. Corresponding engagement features of the compression member and the receiver member can be engaged in a secured configuration to inhibit or prevent removal of the compression cap from the receiver member and optionally to substantially prevent longitudinal and/or rotational movement of the compression member with respect to the receiver member.

Abstract: Bone anchor assemblies and methods are provided having a multi-component bone anchor that is configured to allow the shank of the bone anchor to be bottom loaded into a receiver member. In one embodiment, a bone anchor assembly is provided having a shank with a distal threaded portion and a proximal head portion, a receiver member having an aperture formed in a distal end thereof through which the head portion of the shank can be received, the receiver member defining a polyaxial seat, a non-expandable outer ring configured to be polyaxially disposed within the polyaxial seat of the receiver member and defining a central opening through which the head portion of the shank can be received, and an expandable inner ring having an inner surface configured to mate with the head portion of the shank and an outer surface configured to mate with an inner surface of the outer ring to thereby lock the outer ring in a fixed position relative to the shank.

Abstract: Systems and methods are disclosed in which a distraction sleeve can be attached to a bone anchor assembly to lock or limit the polyaxial degree of freedom of the bone anchor assembly and facilitate true parallel distraction. In some embodiments, the distraction sleeve can lock polyaxial movement of the bone anchor assembly without directly engaging the shank of the bone anchor assembly, without directly engaging the exterior of the receiver member of the bone anchor assembly, and/or without requiring that a rod or closure mechanism be installed in the bone anchor assembly. The distraction sleeve can be preloaded onto the bone anchor assembly prior to inserting the bone anchor assembly using a selectively detachable driver, thereby providing simplified, streamlined insertion and facilitating use with protection and/or retraction sheaths. Countertorque tubes, torque wrenches, and other related instrumentation are also disclosed herein.

Abstract: Bone anchor assemblies are disclosed herein and include bone anchors, receiver members, and closure mechanisms. In one embodiment, a receiver member can be configured to seat a portion of a bone anchor and to receive a spinal fixation element, such as a rod. In an exemplary embodiment, the receiver member is bottom-loading and can include a seat having an opening that can be selectively increased and decreased in size so as to allow a bone anchor to be bottom-loaded. A force can be applied to the receiver member to increase a size of the opening, allowing a portion of the anchor to pass through the opening and into the seat. A closure element can be coupled to the receiver member and can apply a force to decrease a size of the seat and a size of the opening, angularly fixing the receiver member relative to the bone anchor.

Abstract: Bone anchor assemblies are disclosed herein that include one or more features for indicating the relative positioning of the receiver member and the shank, or for selectively maintaining the receiver member and the shank in a fixed relative position. For example, the head of the shank can include a surface feature that interacts with a drag ring to provide tactile or audible feedback when the shank is positioned at a particular orientation with respect to the receiver member. By way of further example, the head of the shank and a compression cap disposed in the receiver member can each include engagement features that cooperate to allow for selective locking of the orientation of the shank with respect to the receiver member.

Abstract: Driver instruments are disclosed herein with various features for improving usability, easing the task of cleaning or sterilizing the instrument, reducing patient trauma associated with use of the instrument, and/or reducing the cost and assembly burden of the instrument. For example, a driver instrument can include a guide sleeve to protect patient tissue from damage caused by rotating components of the instrument or a bone anchor assembly coupled thereto, and to protect extension tabs of the bone anchor assembly from inadvertent separation. By way of further example, an instrument can include a preload assembly for maintaining engagement of a driver shaft of the instrument with a bone anchor assembly. As yet another example, an instrument can consist of a small number of components which are configured for simple, tool-free assembly and disassembly. An instrument can also be configured for use with bone anchor assemblies with and without extension tabs.

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 surface of the bone. In an exemplary embodiment, a bone anchor assembly is provided that includes a bone anchor configured to engage bone, a receiver member for seating a head of the bone anchor, and a compression member for securing the bone anchor at fixed angle with respect to the receiver member when the compression member is seated within the receiver member. Corresponding engagement features of the compression member and the receiver member can be engaged in a secured configuration to inhibit or prevent removal of the compression cap from the receiver member and optionally to substantially prevent longitudinal and/or rotational movement of the compression member with respect to the receiver member.

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.

Abstract: Devices and methods for selectively converting polyaxial bone screws into monoaxial screws are described herein. In one embodiment, a spinal screw extension instrument is provided having an outer component configured to engage a receiving member of a polyaxial screw. The instrument further includes an inner component disposed within an inner lumen of the outer component and configured to translate longitudinally relative to the outer component such that the inner component can apply a distal force to a compression member of the polyaxial screw disposed within a distal portion of the receiving member to thereby convert the polyaxial screw to a monoaxial screw.

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 surface of the bone. In an exemplary embodiment, a bone anchor assembly is provided that includes a bone anchor configured to engage bone, a receiver member for seating a head of the bone anchor, and a compression member for securing the bone anchor at fixed angle with respect to the receiver member when the compression member is seated within the receiver member. Corresponding engagement features of the compression member and the receiver member can be engaged in a secured configuration to inhibit or prevent removal of the compression cap from the receiver member and optionally to substantially prevent longitudinal and/or rotational movement of the compression member with respect to the receiver member.

Abstract: A cannulated bone anchor assembly includes a bone anchor, a receiver member for receiving a spinal fixation element to be coupled to the bone anchor, and a closure mechanism to fix the spinal fixation element with respect to the receiver member. The bone anchor includes a distal shaft having a first threaded section distal to a proximal head, a second threaded section distal to and adjacent the first threaded section, and a third threaded section distal to and adjacent the second threaded section. The first threaded section having a constant major and minor diameter. The second threaded section having a tapering major and minor diameter. The third threaded section having a tapering major diameter and a constant minor diameter.

Abstract: Devices and methods for selectively converting polyaxial bone screws into monoaxial screws are described herein. In one embodiment, a spinal screw extension instrument is provided having an outer component configured to engage a receiving member of a polyaxial screw. The instrument further includes an inner component disposed within an inner lumen of the outer component and configured to translate longitudinally relative to the outer component such that the inner component can apply a distal force to a compression member of the polyaxial screw disposed within a distal portion of the receiving member to thereby convert the polyaxial screw to a monoaxial screw.

Abstract: Various methods and devices for inserting a guidewire into the body are provided. In one embodiment, a guidewire insertion device is provided and includes and outer sheath having an outer surface and an inner lumen extending therethrough, and a dilator having an inner lumen extending therethrough and having a length greater than a length of the outer sheath. A guidewire can be configured to extend through the inner lumen of the dilator such that the guidewire is removably and replaceably disposable within the dilator and coupled thereto. A locking mechanism can be effective to selectively configure the guidewire between a locked position in which the guidewire is stationary relative to the dilator and an unlocked position in which the guidewire is movable relative to the dilator.

Abstract: A cannulated bone anchor assembly includes a bone anchor, a receiver member for receiving a spinal fixation element to be coupled to the bone anchor, and a closure mechanism to fix the spinal fixation element with respect to the receiver member. The bone anchor includes a distal shaft having a first threaded section distal to a proximal head, a second threaded section distal to and adjacent the first threaded section, and a third threaded section distal to and adjacent the second threaded section. The first threaded section having a constant major and minor diameter. The second threaded section having a tapering major and minor diameter. The third threaded section having a tapering major diameter and a constant minor diameter.

Abstract: Bone anchor assemblies are disclosed herein and include bone anchors, receiver members, and closure mechanisms. In one embodiment, a receiver member can be configured to seat a portion of a bone anchor and to receive a spinal fixation element, such as a rod. In an exemplary embodiment, the receiver member is bottom-loading and can include a seat having an opening that can be selectively increased and decreased in size so as to allow a bone anchor to be bottom-loaded. A force can be applied to the receiver member to increase a size of the opening, allowing a portion of the anchor to pass through the opening and into the seat. A closure element can be coupled to the receiver member and can apply a force to decrease a size of the seat and a size of the opening, angularly fixing the receiver member relative to the bone anchor.

Abstract: Bone anchor assemblies and methods are provided having a multi-component bone anchor that is configured to allow the shank of the bone anchor to be bottom loaded into a receiver member. In one embodiment, a bone anchor assembly is provided having a shank with a distal threaded portion and a proximal head portion, a ball having a spherical exterior surface and a central lumen sized to receive the head portion of the shank, and a clip configured to be engaged between the head portion and the ball such that the clip is effective to lock the ball in engagement with the shank.

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 seats a spherical head of the bone anchor and a spinal fixation element, a compression member seated within the receiver member, proximally of the head of the bone anchor, and a closure mechanism seated within the receiver member, proximally of the compression member. One or more of the receiver member, the compression member, and the closure mechanism can have gripping features thereon configured to secure the bone anchor and/or the spinal fixation element within the receiver member, thereby reducing a risk of slippage of the bone anchor and/or the spinal fixation element with respect to the receiver member.

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 surface of the bone. In an exemplary embodiment, a bone anchor assembly is provided that includes a bone anchor configured to engage bone, a receiver member for seating a head of the bone anchor, and a compression member for securing the bone anchor at fixed angle with respect to the receiver member when the compression member is seated within the receiver member. Corresponding engagement features of the compression member and the receiver member can be engaged in a secured configuration to inhibit or prevent removal of the compression cap from the receiver member and optionally to substantially prevent longitudinal and/or rotational movement of the compression member with respect to the receiver member.

Abstract: Bone anchor assemblies are disclosed herein and include bone anchors, receiver members, and closure mechanisms. In one embodiment, a receiver member can be configured to seat a portion of a bone anchor and to receive a spinal fixation element, such as a rod. In an exemplary embodiment, the receiver member is bottom-loading and can include a seat having an opening that can be selectively increased and decreased in size so as to allow a bone anchor to be bottom-loaded. A force can be applied to the receiver member to increase a size of the opening, allowing a portion of the anchor to pass through the opening and into the seat. A closure element can be coupled to the receiver member and can apply a force to decrease a size of the seat and a size of the opening, angularly fixing the receiver member relative to the bone anchor.