Integrated multi-point set screw

Abstract

Disclosed herein are bone anchor assemblies and related methods that can provide improved fixation of a primary bone anchor. A bone anchor assembly (100) includes a base (104) rotatably received within a rod receiving member (106). The base has an annular body with a radially extending portion (116) that includes at least one supplemental bone anchor opening (124) that can receive a supplemental bone anchor to augment fixation of a primary bone anchor of the bone anchor assembly. The base is rotatable relative to the rod receiving member and the primary bone anchor such that the at least one supplemental bone anchor opening can be placed in a desired location for supplemental fixation.

Description

TECHNICAL FIELD

[0001] Orthopedic implants and related methods are disclosed herein. For example, a bone anchor assembly having a plurality of bone engagement points is disclosed. BACKGROUND

[0002] Bone anchor assemblies can be used in orthopedic surgery to fixate bone during healing, fusion, or other processes. For example, in spinal surgery, bone anchor assemblies can be used to fixate spinal fixation elements to one or more vertebrae to rigidly or dynamically stabilize the spine. Bone anchor assemblies can also be used as engagement points for manipulating bone (e.g., distracting, compressing, or rotating one vertebrae relative to another, reducing long bone fractures, etc.).

[0003] The integrity of the bone anchor assembly's engagement with the bone can affect the transmission of corrective biomechanical forces. While a great deal of care is taken when placing a bone anchor assembly, the bone anchor assembly often will be inserted in a compromised state. For example, the bone opening in which the assembly is disposed can be stripped (e.g., by tapping the bone anchor assembly beyond its optimal holding position), the bone anchor assembly can be improperly placed (e.g., manipulated using an improper instrument, such as an oversized pilot hole), the bone anchor assembly can be placed outside of its intended trajectory (e.g., within the joint capsule or breaking through the pedicle wall), or the bone anchor can be inserted into compromised bone (e.g., fractured, osteoporotic, diseased, or otherwise lacking structural integrity).

[0004] When a bone anchor assembly is in a compromised state, there can be suboptimal purchase between the bone anchor assembly and the bone. The surgeon can feel that the bone anchor assembly is unsafe, and the bone anchor assembly can back out or loosen over time. When faced with these types of situations, the surgeon's options are limited. For example, in spinal surgery, the surgeon can remove the bone anchor assembly and skip the vertebral level, but this can undesirably require expanding the surgical site to additional vertebral levels. The surgeon can remove and reinsert a larger anchor, but this can not be an option when there is limited space for anchoring in the bone. The surgeon can leave the compromised bone anchor assembly in place, which can be the safest alternative if the bone anchor assembly is in a safe position and attachment to a plate, rod, or other implant construct is certain, as additional compromised fixation can be better than removal.

[0005] Even when a bone anchor assembly is in a non-compromised state, the geometry of conventional bone anchor assemblies limits the flexibility of the positioning of the bone attachment points relative to a plate, rod, or other implant construct coupled to the bone anchor assembly.

[0006] There is an ongoing need for improved bone anchor assemblies and related methods. SUMMARY

[0007] Disclosed herein are bone anchor assemblies that can provide improved fixation as compared to conventional bone anchor assemblies. Embodiments of the assemblies can include a multi-point eyelet component as part of a bone anchor base. The eyelet component can allow the eyelet to be positioned at any desired location around the circumference of a receiver member component in a manner that is integrated into the receiver member component. The eyelet component can accommodate one or more secondary bone anchors that enhance fixation of a primary bone anchor of the assembly. Also disclosed are surgical methods of using the bone anchor assemblies described herein.

[0008] In one aspect, a bone anchor assembly can include a base, a receiver member, and a shank. The base can include an annular body portion and a radial protrusion (e.g., an eyelet or a wing) extending radially from the annulus, the radial protrusion having at least one secondary bone anchor opening configured to receive a secondary bone anchor. The receiver member can have a proximal end, a distal end, a lumen extending from the proximal end to the distal end, and a rod-receiving recess. The shank can have a head portion retained within the annular body of the base and a bone-engaging portion extending distally from the base. The base can be coupled to the receiver member such that the base is configured to rotate relative to the receiver member.

[0009] The devices and methods described herein can have a variety of additional features and / or variations, all of which are within the scope of the present disclosure. In some embodiments, for example, the annular body of the base can extend distally from the receiver member. The base can include an extension that can extend proximally from the annular body. The extension can be received within the lumen of the receiver member. In some such embodiments, the extension can have a first connection feature and the receiver member can have a second connection feature. The first connection feature can be configured to engage with the second connection feature such that the base can be rotatably received within the receiver member. Further, in some embodiments, the first and second connection features can be configured such that relative axial movement between the base and the receiver member can be limited when the first connection feature is engaged with the second connection feature. In some embodiments, the first connection feature can be a lip at a proximal end of the extension and the second connection feature can be a groove in an inner surface of the receiver member. The groove of the receiver member can be distal to the rod-receiving recess.

[0010] In some embodiments, a bone anchor assembly can include a saddle disposed within a receiver member. The saddle can have a distally facing surface that can contact a proximally facing surface of an extension of a base when the base is disposed within the receiver member. In some embodiments, the at least one secondary bone anchor opening of the base can include a plurality of secondary bone anchor openings. The central lumen of the at least one secondary bone anchor opening can extend at a transverse angle relative to a central axis of the receiver member. The central lumen of the at least one secondary bone anchor opening can be angled in one of a caudal direction and a cranial direction. In some embodiments, the central lumen of the at least one secondary bone anchor opening can be angled in one of a medial direction and a lateral direction.

[0011] In another aspect, a surgical method can include driving a shank portion of a bone anchor into a bone of a patient and rotating a base of a bone anchor assembly relative to a receiver member of the bone anchor assembly, the base having a radial projection with at least one secondary bone anchor opening extending therethrough and the receiver member being configured to receive a spinal fixation element. The method can include positioning the radial projection of the bone anchor at a desired location relative to the shank portion and driving at least one secondary bone anchor through the at least one secondary bone anchor opening and into the bone of the patient.

[0012] In some embodiments, driving the at least one secondary bone anchor through the at least one secondary bone anchor opening and into the bone of the patient can include driving the secondary bone anchor through the secondary bone anchor opening along an insertion trajectory that can be offset relative to at least one of a central axis of the receiver member and the shank to supplement fixation of the bone anchor within the bone. Rotating the base of the bone anchor assembly can include rotating the base about a central longitudinal axis of the receiver member.

[0013] In some embodiments, the method can include placing a spinal rod within the receiver member and securing the spinal rod within the receiver member prior to driving the at least one secondary bone anchor into the bone. In other embodiments, placing a spinal rod within the receiver member and securing the spinal rod within the receiver member can occur after driving the at least one secondary bone anchor into the bone.

[0014] The method can also include assembling the bone anchor by coupling the base to the receiver member such that the base is rotatable relative to a central longitudinal axis of the receiver member and inserting the shank through the receiver member and the base such that a distal bone-engaging portion of the shank extends distally from the base and a head portion of the shank is received within the base. In some embodiments, the shank can be multi-axially rotatable relative to the base.

[0015] Any of the above features or variations can be applied in a variety of different combinations to any particular aspect or embodiment of the present disclosure. No particular combination has been explicitly recited merely to avoid undue repetition in the summary of the invention. BRIEF DESCRIPTION OF DRAWINGS

[0016] The aspects and embodiments of the present disclosure described above will become more fully understood from the detailed description, given below, and the accompanying drawings, wherein:

[0017] Figure 1 is an exploded perspective view of one embodiment of a bone anchor assembly of the present disclosure;

[0018] Figure 2 is an exploded perspective view of another embodiment of a bone anchor assembly of the present disclosure;

[0019] Figure 3 is a cross-sectional view of the bone anchor assembly of Figure 2 ; and

[0020] Figure 4 schematically illustrates the receiver of the bone anchor assembly of Figure 2 in a first position relative to the base of the bone anchor assembly of Figure 2 ; and

[0021] Figure 5 schematically illustrates the receiver of the bone anchor assembly of Figure 2 rotated to a second position relative to the base of the bone anchor assembly of Figure 2 . DETAILED DESCRIPTION

[0022] Certain example embodiments will now be described to provide an overall understanding of the principles of the structure, function, manufacture, and use of the devices, systems, and methods disclosed herein. One or more of these embodiments are illustrated in the accompanying drawings. The devices, systems, and methods specifically described herein and illustrated in the drawings are non-limiting embodiments. Features shown or described in connection with one embodiment can be combined with features of other embodiments. Such modifications and variations are intended to be included within the scope of the present disclosure.

[0023] Disclosed herein are bone anchor assemblies that can provide improved fixation as compared to conventional bone anchor assemblies. The disclosed bone anchor assemblies can include a primary screw shank for engagement with a bone, a base having a radially extending protrusion (e.g., a protruding eyelet, a wing, etc.) with at least one secondary bone anchor opening to receive a secondary bone anchor, and a receiver member for receiving a spinal fixation element. The base can be coupled with the receiver member such that the base can be rotated relative to and independent of the receiver member and the primary shank. In this manner, once the primary screw shank is engaged with a bone (e.g., a vertebra of a patient), the base can be rotated to adjust one or more secondary bone anchor openings relative to the receiver member and the bone anchor positioning.

[0024] The bone anchor assembly can be assembled by inserting the screw shank into the base such that the proximal head of the screw shank can be seated or otherwise retained within the base with the distal bone engaging portion of the screw shank extending distally from the base. The base can be inserted into and coupled with the receiver member such that the base can be rotated relative to the receiver. The screw shank can be driven into the patient anatomy (e.g., a vertebra) and the base can be freely rotated about the longitudinal axis of the receiver member to position one or more secondary bone anchor openings on the protrusion (e.g., eyelet, wing, etc.) of the base to provide desired supplemental fixation in addition to the primary screw shank. One or more secondary bone anchors (also referred to herein as supplemental fixation screws) can then be inserted into the secondary bone anchor openings to provide supplemental fixation. A spinal fixation rod can be placed and / or fixed within the receiver member before or after placement of the supplemental fixation screws. Thus, the disclosed bone anchor assemblies can provide supplemental fixation to a primary screw in a strategic and patient-specific manner without the need for additional components beyond the bone anchor assembly.

[0025] Figure 1 An exploded view of an embodiment of a bone anchor assembly 100 according to the present disclosure is shown. As noted above, bone anchors can sometimes be inserted in a damaged state. This can be undesirable, especially in cases where there is limited room to install additional bone anchors. The illustrated bone anchor assembly 100 can allow for supplemental fixation of a primary bone anchor in a compact footprint without necessarily requiring removal or reinsertion of the primary bone anchor. As shown, the bone anchor 100 can include a primary bone anchor 102 (also referred to as a primary screw shank), a base 104, a receiver member 106 for receiving a spinal fixation element (not shown) coupled to the bone anchor, such as a spinal rod, and one or more secondary bone anchors 108. A closure mechanism (not shown), such as a set screw, can capture and secure the spinal fixation element within the receiver member 106 relative to the receiver member. The spinal fixation element (e.g., spinal rod) can directly contact the receiver member 106 (or other components such as the base 104 and / or the bone anchor 102) or can contact an intermediate element (e.g., a saddle 105, as for example Figure 2 and Figure 3The base 104 can be coupled to the receiver member 106 in use such that the base can rotate relative to the receiver member about a central longitudinal axis Al of the receiver member, but relative movement along the longitudinal axis Al can be limited or defined. One or more supplemental set screws 108 can be driven through corresponding one or more supplemental bone anchor openings 124 of the base 104 into the bone and can supplement fixation of the bone anchor 102 within the patient anatomy.

[0026] The primary screw shank 102 can include a distal threaded shaft 110 configured to engage bone and a proximal head 112. The proximal head 112 can generally have a truncated spherical shape including a flat proximal surface and an approximately spherical distal surface. The proximal head 112 of the screw shank 102 can engage with a distal end of the base 104, for example, in a ball and socket arrangement in which the proximal head 112 can pivot relative to the base 104. The distal surface of the proximal head 112 of the shank 102 and a mating surface within the distal end of the base 104 can have any shape that facilitates this arrangement, including, for example, spherical, toroidal, conical, frustoconical, and any combination thereof.

[0027] The distal shaft 110 of the shank 102 can be configured to engage bone and, in the illustrated embodiment, can include external bone-engaging threads. The thread form of the distal shaft 110, including the number of threads, the thread pitch, the major and minor thread diameters, and the thread shape, can be selected to facilitate connection with bone. Exemplary thread forms are disclosed in U.S. Patent Application Publication 2011 / 0288599, filed May 18, 2011, and U.S. Patent Application Publication 2013 / 0053901, filed August 22, 2012, both of which are incorporated by reference herein.

[0028] The base 104 can have an annular body portion 114 with a radial protrusion (e.g., eyelet or wing) 116 extending radially therefrom. An extension 118 can extend proximally from the annular body 114. The proximal extension 118 can include a lip 120 or other connection feature such as one or more prongs, grooves, etc. for engagement with a complementary connection feature of the receiver 106. In some embodiments, the extension 118 and lip 120 can be deformable. For example, the lip 120 can compress radially inward when the lip 120 is received within the inner cavity 136 of the receiver member 106, and can expand radially outward from the compressed position when the lip 120 is aligned with the groove 142 of the receiver member. In this manner, the lip 120 of the base 104 can engage with the groove 142 of the receiver member 106 to retain the base 104 within the receiver member 106. In some embodiments, the lip 120 and extension 118 can be a unitary structure that is deformable. In other embodiments, the connection feature (e.g., lip 120) can be formed on or extend from the annular body 114 itself, and the proximal extension 118 can be omitted.

[0029] An inner cavity 122 having a central longitudinal axis Al can extend through the base 104, and more particularly, through the annular body 114 and the proximal extension 118. The screw shank 102 can be inserted through the inner cavity 122 such that the distal threaded portion 110 extends distally from the annular body 114, while the head portion 112 of the screw shank 102 can be received within the annular body 114. In some embodiments, the interior surface of the annular body 114 can include features complementary to the proximal head 112 of the screw shank 102 such that the screw shank can be retained within the annular body 114 and, in some embodiments, can be moved polyaxially relative to the annular body. While the above describes a “top-down” assembly in which the screw shank 102 is passed distally through the base 104 until the proximal head 112 is received within the annular body 114 of the base, in other embodiments, the assembly can be configured for “bottom-up” loading in which the screw shank 102 is passed proximally through the base 104 in order to seat the proximal head 112 into the annular body 114. This can be accomplished, for example, by forming the annular body 114 and / or the proximal head 112 such that it is deformable to allow the proximal head to pass through a recess of the annular body. Examples of features that allow such coupling can include the use of elastically deformable materials, resilient fingers that form a collet or other gripping structure, etc.

[0030] The protrusion or wing 116 can extend from the annular body 114 and can form a portion of the base 104. The protrusion 116 can extend radially outward from the annular body 114, i.e., away from the central longitudinal axis Al of the inner cavity 122. An auxiliary bone anchor opening 124 can be formed in the wing 116. While in the illustrated embodiment the wing 116 is a single, continuous structure, in other embodiments the wing 116 can be formed of two or more separate structures.Figure 1 A single opening 124 is shown on the wing 116, but in some embodiments, the wing 116 may include multiple auxiliary bone anchor openings 124. The auxiliary bone anchor openings 124 may be configured to receive auxiliary fixation elements 108. For example... Figure 1 As shown, the central longitudinal axis A2 of the opening 124 may extend substantially parallel to the central longitudinal axis A1 of the lumen 122. In other embodiments, the opening 124 may extend along an offset or angled trajectory relative to the central axis A1 of the lumen 122. For example, the central axis A2 of the opening 124 may extend at an angle relative to the central longitudinal axis A1 of the lumen 122. In this way, the auxiliary bone anchor 108 may be received through the auxiliary bone anchor opening 124 and may be positioned within the patient's anatomy along a tail or head trajectory (depending on the placement of the protrusion 116 relative to the patient's anatomy). Alternatively or additionally, the central axis A2 of the opening 126 may extend radially inward toward or away from the central axis A1 of the opening 122. In embodiments having a plurality of auxiliary bone anchor openings 124 in the protrusion 116, each opening 124 may be angled or offset to have the same or different trajectories. Further features and embodiments of the auxiliary bone anchor opening can be found in U.S. Patent Application Serial No. 16 / 583,233, filed September 25, 2019, entitled “Multipoint Angled Fixation Implants for Multiple Screws and Related Methods,” the entire contents of which are incorporated herein by reference.

[0031] In some embodiments, each auxiliary bone anchor opening 124 may include any one of a plurality of features for receiving the auxiliary bone anchor 108 at different angles, such as conical, spherical, or parabolic threads. For example, as described in U.S. Patent Application Serial No. 16 / 583,233. Figure 2 A to Figure 2 As discussed in M, the opening 124 can be at least partially threaded to receive a variable-angle locking screw 108 having a threaded proximal head 132. (As...) Figure 1As shown, the opening 124 can have a plurality of threaded posts 128 spaced apart to define a plurality of non-threaded recesses 130. In this manner, the threads of the opening 124 can form an interlocking interface and cooperate with the threads 125 of the supplemental fixation screw 108 to lock the screw 108 therein. In one embodiment, the threads of the opening 124 can be conical threads. The threaded posts 128 can be disposed about the inner surface of the opening 124 for engaging the threads 132 on the head of the variable angle auxiliary bone screw 108 and / or the locking member. Thus, the supplemental fixation screw 108 can be locked within the protrusion 116, and more particularly within the opening 124, coaxially with the central axis Al of the base 104 or at a selected angle within a selectable range of angles relative to the central axis of the base, in one embodiment. For example, the screw 108 can be inserted into the opening 124 along a trajectory A3 that can extend at a transverse angle relative to the central axis A2 of the opening. The opening 124 can have any number (e.g., two, three, four, etc.) of threaded posts 128 to facilitate variable angle locking with the supplemental fixation screw 108. Additionally or alternatively, the opening 124 can include one or more additional locking components such as cams, and / or can facilitate locking with the screw 108 through deformation of the material (e.g., opening up of the auxiliary bone anchor opening).

[0032] The auxiliary bone anchor 108 can include features to facilitate such variable angle locking, such as a proximal head that is at least partially spherical having threads with a profile that follows the arcuate radius of curvature of the spherical portion of the head. The variable angle capability of the interlocking interface (i.e., screw / opening interface) can allow the user to place the locking auxiliary bone anchor into the bone at any angle within the angular limits, providing improved placement flexibility and eliminating or reducing the need to conform the wing 116 to the bone surface to achieve the desired insertion angle. Thus, the auxiliary bone anchor 108 can be driven into the bone along diverging or converging longitudinal axes relative to the primary bone anchor 102. In cases where multiple bone anchors 108 can each be driven through openings of the protrusion 116, the bone anchors 108 can be driven into the bone along diverging or converging longitudinal axes relative to one another and / or relative to the primary bone anchor 102. The offset or angled trajectory of the auxiliary bone anchor 108 can provide improved resistance to pullout. The locking interface between the auxiliary bone anchor opening and the auxiliary bone anchor can increase stability and prevent the auxiliary bone anchor from backing out of the opening.

[0033] As described above, the auxiliary bone anchor opening 124 can include a locking interface having one or more locking features to lock the head of the auxiliary bone anchor within the opening 124. In other embodiments, the opening 124 can have a trailing interface with the auxiliary bone anchor, where the head of the auxiliary bone anchor is not independently locked relative to the opening 124. In some such embodiments, the interior surface of the opening 124 can be smooth or spherical, absent threads or locking features.

[0034] The receiver member 106 can have a proximal end 106p, a distal end 106d, and a lumen 136 extending between the proximal and distal ends. The proximal end 106p can have a pair of spaced apart arms 138A, 138B defining a U-shaped rod-receiving recess 140 therebetween for receiving a spinal fixation element, such as a spinal rod. Each of the arms 138A, 138B can extend from the distal end 106d of the receiver member 106 to a free end. The outer surface of each of the arms 138A, 138B can include features such as recesses, dimples, notches, protrusions, etc. to facilitate connection of the receiver member 106 with an instrument. For example, the outer surface of each arm 138A, 138B can include an arcuate groove at the respective free end of the arms. Such grooves are described in greater detail in U.S. Patent 7,179,261, published February 20, 2007, which is incorporated by reference herein. A closure mechanism such as a set screw (not shown) can be positioned between and engageable with the arms 138A, 138B to capture a spinal fixation element (e.g., a spinal rod) (not shown) within the receiver member 106 and fix the spinal fixation element relative to the receiver member. For example, the arms 138A, 138B can have internal threads 141 that are engageable with external threads of the closure mechanism.

[0035] The distal end 106d of the receiver member 106 can have a distal end surface that is generally annular in shape defining an opening through which at least a portion of the base 104 and handle 102 extend. For example, the extension 118 of the base 104 can be inserted through the distal opening of the receiver member 106 so that the lip 120 of the extension can engage the groove 142 of the receiver member and the annular body 114 of the base can extend distally from the receiver member. As referenced above, the extension 118 of the base 104 can include a pair of spaced apart arms 122A, 122B that define a U-shaped recess 124 therebetween for receiving a spinal fixation element, such as a spinal rod. Each of the arms 122A, 122B can extend from the distal end 106d of the receiver member 106 to a free end. The outer surface of each of the arms 122A, 122B can include features such as recesses, dimples, notches, protrusions, etc. to facilitate connection of the receiver member 106 with an instrument. For example, the outer surface of each arm 122A, 122B can include an arcuate groove at the respective free end of the arms. Such grooves are described in greater detail in U.S. Patent 7,179,261, published February 20, 2007, which is incorporated by reference herein. A closure mechanism such as a set screw (not shown) can be positioned between and engageable with the arms 122A, 122B to capture a spinal fixation element (e.g., a spinal rod) (not shown) within the receiver member 106 and fix the spinal fixation element relative to the receiver member. For example, the arms 122A, 122B can have internal threads 141 that are engageable with external threads of the closure mechanism. Figures 2 to 4 As described in detail above, the base 104 can be coupled with the receiver member 106 so that the base can rotate relative to the receiver member about a central longitudinal axis of the receiver member.

[0036] In the assembled configuration of the bone anchor assembly 100, the central longitudinal axis of the inner cavity 136 of the receiver member 106 can be coaxial with the central longitudinal axis Al of the inner cavity 122 of the base. The base 104 can be coupled with the receiver member 106 such that the base 104 can rotate about the central axis Al relative to the receiver member. In some embodiments, the base 104 can rotate 360 degrees in either a clockwise or counterclockwise direction about the central axis Al relative to the receiver member. However, relative axial movement between the base 104 and the receiver member 106 along the central axis Al can be limited or restricted. The receiver member 106 can receive a spinal fixation element such as a spinal rod (not shown) within the rod receiving recess 140 such that the spinal fixation element can extend laterally relative to the longitudinal axis Al.

[0037] The structure, assembly, and use of the bone anchor assemblies of the present disclosure will now be described in greater detail with reference to alternative embodiments of a bone anchor assembly 100' as shown in Figure 2 and Figure 3 The structure, assembly, and use of the bone anchor assemblies of the present disclosure will now be described in greater detail with reference to alternative embodiments of a bone anchor assembly 100' as shown in Figure 2 An exploded perspective view of the bone anchor assembly 100' is shown, and Figure 3 A cross-sectional view of the assembled bone anchor of Figure 2 In use, the base 104' can be received within the receiver member 106' such that the annular body 114' can extend distally from the receiver member and the base can rotate relative to the receiver. Optionally, a saddle 105 can be interposed between the base 104' and a spinal fixation element (not shown) received within the receiver member 106'. The head 112 of the handle 102 can be received within the base 104' while the distal shaft 110 of the handle can extend distally from the base and thus from the receiver member 106' to engage with bone. The protruding portion 114' can rotate relative to the receiver 106' and can be positioned such that one or more auxiliary bone anchor openings 124' can be strategically positioned relative to the handle 102 and patient anatomy to provide desired supplemental fixation. One or more auxiliary bone anchors can be driven through the one or more auxiliary bone anchor openings in the protruding portion of the base to engage with bone and provide supplemental fixation support to the primary bone anchor.

[0038] The lip 120' of the base 104' can be received within the groove 142' of the receiver member 106', allowing the base 104' to rotate relative to the receiver member 106' about axis A1. However, relative axial movement (i.e., movement along axis A1) may be limited by, for example, the tolerance dimensions of the groove 142 relative to the lip 120' and / or the length of the extension 118' of the base 104' in the direction along axis A1. In some embodiments, the extension 118' and the lip 120' may include one or more deformable fingers 121 with a gap 123 therebetween. When received within the cavity 136' of the receiver member 106', the fingers 121 may compress radially inward and expand outward when the lip 120' is aligned with the groove 142' of the receiver member. Although Figures 1 to 3 The illustrated embodiment shows lips 120, 120' as connecting features of bases 104, 104' and grooves 142, 142' as complementary connecting features of receiver members 106, 106'. However, alternative complementary connecting features may be used as long as the connection between the base and the receiver member allows for relative rotation between them, and they are all within the scope of this disclosure. As a non-limiting example, grooves or one or more forks may be formed on the inner distal surface of receiver member 106 and may engage with grooves formed on the outer surface of extension 118.

[0039] Figure 3 A base 104' and a saddle 105 are shown received within a receiver member 106'. At least a portion of the extension 118' of the base 104' can be received within the distal portion of the cavity 136' of the receiver member 106', such that the annular body 114' of the base extends distally from the distal surface of the receiver member. As discussed above, the lip 120' of the extension 118' can be deformable and can be radially inwardly compressed during insertion of the extension into the receiver member 106'. Then, when the lip is aligned with the groove 142' of the receiver member 106', the lip 120' can extend to its initial state, as... Figure 3 As shown, the base 104' can be held within the receiver member. The proximal surface of the annular body 114' can contact the distal surface of the receiver member 106'. In other embodiments, a portion of the extension 118' can extend distally from the receiver member 106' such that the annular body 114' does not contact the receiver member 106'. As described above, the wing 116' can extend radially outward from the annular body 114' along the central axis A1, i.e., radially outward relative to the cavity 122 of the base 104'. In the assembled configuration, the wing 116', having at least one auxiliary bone anchor opening 124, can rotate relative to the receiver member 106' together with the base 104'.

[0040] A saddle 105 may be received within a cavity 136' of a receiving member 106', wherein at least a portion of the saddle contacts a base 104'. The saddle 105 may have a proximal portion 105p, a distal portion 105d, and a cavity 107 extending between the proximal and distal portions. The saddle 105 may include a pair of spaced-apart arms 109A, 109B whose walls define a distally facing surface 113 of a U-shaped seat 111 for receiving a spinal fixation element and the proximal portion 105p, which may abut a proximal facing surface of the base 104' and / or a portion of the proximal head 112 of the screw shank 102. The distal portion 105d of the saddle 105 may be received within an extension 118' of the base 104', such that the distal portion of the saddle extends into a cavity 122 of the base. The saddle 105 can be positioned within the receiver member 106' and inserted between the base 104 and the spinal fixation element in the rod receiving recess 140. For example, the saddle 105 can be inserted into the cavity 136 of the receiver member 106 such that the arms 109A, 109B are radially inwardly deflected. As the saddle 105 advances to a position where the distal portions of the arms 109A, 109B align with the grooves 143 formed in the receiver member 106, these arms can be radially outwardly extended to partially accommodate themselves within the grooves 143, thereby holding the saddle to the receiver member. The dimensions of the grooves 143 and the portions of the arms 109A, 109B configured to be received therein can be configured to allow desired axial movement of the saddle 105 relative to the receiver member 106 (when, for example, the force applied by the saddle on the handle 102 varies). More specifically, with the proximal head 112 of the handle 102 received within the base 104', the saddle 105 can compress the distal outer surface of the head of the handle 102 into direct and fixed engagement with the distal inner surface 119 of the base 104'. The head 112 of the handle 102 can be received and held within the base 104' (i.e., within the cavity 122'), while the distal shaft 110 of the handle can extend distally from the annular body 114' of the base 104'. The handle 102 can be inserted into the base 104' before or after the base 104' is inserted into the receiving member 106'.

[0041] In the assembly configuration, the base 104' can rotate 360 ​​degrees relative to the receiver 106'. For example, Figure 4 A top view is shown of a first position of the base 104′ relative to the receiver member 106′, wherein the wing 116′ can extend to the left side of the receiver (see reference). Figure 4 (as shown in the view), essentially located at the centerline of receiver arm 138A'. Base 104' is rotatable relative to receiver 106' in a clockwise or counterclockwise direction, as indicated by arrows 202 and 204 respectively. For example, a user can grasp wing 116' or annular body 114' and rotate base 104' clockwise to place wing 116' in a second position (e.g.,Figure 5 The position shown is different from the first position.

[0042] One embodiment of the method of using the bone anchor assembly 100 will now be described. The bone anchor assembly 100 can be assembled prior to implantation into a patient. The screw shank 102 can be loaded into the base 104 from the top. More specifically, the screw shank 102 can extend distally through the cavity 122 of the base 104 such that the shaft 110 of the screw shank can extend distally from the annular body 114 of the base, while the proximal head 112 of the screw shank can be received within the cavity 122 of the base 104. Alternatively, in some embodiments, the screw shank 102 can be loaded into the base 104 from the bottom.

[0043] A base 104, in which a handle 102 is received, can be inserted into a receiver 106 such that the base is rotatable relative to the receiver. More specifically, an extension 118 can be inserted through a distal opening in the receiver 106 and can be moved proximally within a cavity 136 of the receiver until the lip 120 of the base 104 can be captured, for example, within a recess 142 of the receiver 106. Alternatively, the base 104 can be coupled to the receiver 106 before the handle 102 is inserted through it. In such cases, the handle 102 can be moved distally through the cavity 136 of the receiver 106 and the cavity 122 of the base 104. In some embodiments, the base 104 and the receiver member 106 can be manufactured as a single component having a base capable of rotating relative to the receiver member 106, as described herein. As discussed above, when the base 104 is connected to the receiver 106, the base, including the annular body 114 and the wing 116, can rotate about the central axis A1 relative to and independently of the receiver 104.

[0044] Using the receiver assembly 106, base 104, and screw shank 102 (i.e., the assembled main bone anchor), the shank can be screwed into the bone according to standard surgical techniques. For example, the bone anchor assembly 100 may be a multiaxial bone screw designed for later implantation into a pedicle or lateral block of a vertebra. With the shank 102 implanted into the bone, the wings 116 of the base 104 can rotate relative to the shank 102 and receiver 106 to position one or more auxiliary bone anchor openings 124 in the desired location. When positioning the wings 116 and auxiliary bone anchor openings 124, various factors can be considered, including, for example, the placement of the shank 102, patient anatomy, requirements of other instruments and surgical procedures, such as whether the bone to which the shank 102 is engaged is fused with one or more adjacent vertebrae.

[0045] One or more auxiliary bone anchors 108 can then be inserted into the bone through one or more corresponding auxiliary bone anchor openings 124 of the wing 116 to supplement the fixation of the bone anchor 100. As discussed in detail above, one or more auxiliary bone anchors among the auxiliary bone anchors 108 can be inserted along an angled or offset trajectory relative to the central axis A1 of the bone anchor, the stem 102, and / or one or more other auxiliary bone anchors. The spinal rod can be placed within the rod receiving recess 140 of the receiver member 106 and can be secured within the receiver member using a closure (e.g., a fixing screw). One or more auxiliary bone anchors 108 can be placed before and / or secured within the receiver member.

[0046] In any of the above embodiments or methods, the main bone anchor may be omitted, and the user may rely solely on one or more auxiliary fixation features to secure the bone anchor. This advantageously allows for a fixation position completely off-center from the receiver component, for example, if the initially placed bone anchor needs to be removed due to incorrect positioning or insufficient grip, or when the receiver component needs to be positioned where the bone anchor cannot be inserted.

[0047] While the methods described and illustrated herein relate to bone anchors placed in the pedicle or lateral mass of a vertebra, it should be understood that the systems and methods described herein can be used in any bone, non-bone tissue, or non-living or non-tissue object.

[0048] The auxiliary fixation components disclosed herein can be implanted in subsequent surgical procedures using the same surgical procedures as bone anchors, receiver components, and spinal rods, or in the case of revision surgery.

[0049] It should be noted that any order of method steps expressed or implied in the above description or accompanying drawings should not be construed as limiting the disclosed methods to performing the steps in that order. Rather, the various steps of each method disclosed herein can be performed in any of a variety of orders. Furthermore, since the described methods are merely exemplary embodiments, various other methods including additional steps or fewer steps are also covered within the scope of this disclosure.

[0050] As is apparent from the foregoing, in at least some embodiments, the systems and methods disclosed herein can provide enhanced fixation for a given surgical site, providing greater bone fixation strength at a given location, without necessarily requiring the fixation to be moved to another vertebra or skipped / added to the vertebral segment involved.

[0051] The bone anchor assembly and its various components disclosed herein can be made of any of a variety of known materials. Exemplary materials include those suitable for surgical applications, including metals (such as stainless steel, titanium, or alloys thereof), polymers (such as PEEK, ceramics, carbon fibers, etc.). Various components of the device disclosed herein can be rigid or flexible. One or more components or portions of the device may be formed of radiopaque materials to facilitate visualization under fluoroscopic examination and other imaging techniques, or of radiopaque materials so as not to interfere with the visualization of other structures. Exemplary radiopaque materials include carbon fibers and high-strength polymers.

[0052] The methods and devices described above relate to applications in spinal surgery. While this is a contemplated use, the methods and devices disclosed herein are equally applicable to other areas of the patient's body and can be used in any of a variety of surgical procedures performed on humans or animals, and / or in areas unrelated to implants or surgery, with any human or animal implant. Therefore, the devices described herein can be formulated in various sizes and materials to fit various areas of the patient's body. The systems and methods disclosed herein can be used in minimally invasive and / or open surgery.

[0053] While specific embodiments have been described above, it should be understood that various variations are possible within the spirit and scope of the described concept. Therefore, this disclosure is not intended to be limited to the described embodiments, but has the full scope defined by the language of the following claims. All publications and references cited herein are expressly incorporated by reference in their entirety.

Claims

1. A bone anchor assembly, comprising: A base having an annular body portion and a radially extending portion, the radially extending portion including at least one auxiliary bone anchor opening configured to receive an auxiliary bone anchor, the base including an extension extending proximally from the annular body portion; A receiver component having a proximal end, a distal end, an inner cavity extending between the proximal end and the distal end, and a rod receiving recess; and The handle has a head portion held within the annular body portion and a osseous engagement portion extending distally from the base; The base is coupled to the receiver member such that the base is configured to rotate relative to the receiver member, and The extension is received within the cavity of the receiving body member.

2. The bone anchor assembly according to claim 1, wherein, The annular main body portion of the base extends distally from the receiving body component.

3. The bone anchor assembly according to claim 1, wherein, The extension of the base has a first connecting feature, and the receiving member has a second connecting feature. The first connecting feature is configured to engage the second connecting feature, such that the base can be rotatably received within the receiving body member.

4. The bone anchor assembly according to claim 3, wherein, The first connecting feature and the second connecting feature are configured such that when the first connecting feature and the second connecting feature are engaged, the relative axial movement between the base and the receiving body member is restricted.

5. The bone anchor assembly according to claim 3 or claim 4, wherein, The first connecting feature is a lip located at the proximal end of the extension, and the second connecting feature is a groove located in the inner surface of the receiving member.

6. The bone anchor assembly according to claim 5, wherein, The groove of the receiving component is located on the far side of the rod receiving recess.

7. The bone anchor assembly according to any one of claims 1 to 4, further comprising a saddle disposed within the receiver member, the saddle having a distally facing surface configured to contact a proximally facing surface of the extension disposed within the receiver member.

8. The bone anchor assembly according to any one of claims 1 to 4, wherein, The at least one auxiliary bone anchor opening in the radially extended portion further includes a plurality of auxiliary bone anchor openings.

9. The bone anchor assembly according to any one of claims 1 to 4, wherein, The central cavity of the at least one auxiliary bone anchor opening extends at a lateral angle relative to the central axis of the receiver component.

10. The bone anchor assembly according to claim 9, wherein, The central cavity of the at least one auxiliary bone anchor opening is angled in one of the tail direction and the head direction.

11. The bone anchor assembly according to claim 9, wherein, The central cavity of the at least one auxiliary bone anchor opening is angled in one of the medial and lateral directions.

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