Implant receiver and connector with gripping recess for rod fixation

Abstract

Implants with gripping grooves are disclosed herein. In some embodiments, an implant includes a stem-receiving recess defining a stem axis, wherein an inner surface of the stem-receiving recess defines two gripping grooves extending parallel to each other and the stem axis. Each gripping groove defines two edges where the gripping groove intersects the inner surface, the four edges of the two gripping grooves together defining a circular radius about the stem axis. The implant includes a retention member configured to move relative to the body to apply a force to the stem perpendicular to the stem axis that engages the stem against the four edges of the gripping grooves, wherein engagement of the four edges of the gripping grooves against the stem limits rotational movement of the stem about the stem axis.

Description

Technical Field

[0001] This article discloses an implant receiver and a connector with a gripping groove for improved rod fixation. Background Technology

[0002] Fixation systems are used in orthopedic surgery to maintain the desired spatial relationship between multiple bones or bone fragments. For example, various spinal conditions, such as fractures, deformities, and degenerative diseases, can be treated by attaching a spinal fixation system to one or more vertebrae. Such systems typically consist of spinal fixation elements, such as rigid or flexible rods or plates, which are attached to the vertebrae by various anchoring devices, such as screws, hooks, or wires. Once installed, the fixation system holds the vertebrae in the desired position until healing or spinal fusion can occur, or for an additional period of time.

[0003] In screw-and-rod spinal fixation constructs, the stability of the implanted construct is crucial for allowing the body to achieve bone fusion through the surgical segment. Instability or movement within the implanted construct can lead to pseudoarthrosis, or "bone nonunion," where new bone formation cannot withstand the loads experienced by the screw-and-rod construct. Excessive movement between the vertebrae in the instrumented construct hinders growth activity; new bone cannot fuse between two bodies that are constantly moving relative to each other. To address this issue and provide stable fixation, multi-axis screw heads, rod-to-rod, and screw head-to-rod connectors need to be securely held to the rod. These implants must resist movement relative to the longitudinal rod within the construct; this includes rod slippage, rotation, or pulling away from the connector or bone screw.

[0004] In many cases, it may be desirable to connect multiple implants to each other. For example, some revision surgeries involve extending a previously installed construct to another vertebral segment by attaching a newly installed spinal rod to a previously installed rod. Additionally, in cases where vertebral implants or constructs are fixed in the cervical and thoracic regions of the spine, rod-to-rod connectors can be used to bridge the transition between constructs or implants in the cervical and thoracic regions. In this example, and in other transition areas, torsional slippage between implants on rods or between rods connecting implants is a serious risk, which can be caused by routine and repetitive movements, such as a patient twisting their head. As another example, a patient's anatomy, the surgical technique used, or aspects of the required correction may necessitate connecting multiple spinal rods to each other. As yet another example, connecting multiple rods to each other can improve the overall strength and stability of the implant construct.

[0005] Connecting multiple implants to each other can present various challenges. The available space for implant constructs is often very limited, especially in the cervical region of the spine. Furthermore, manipulating and operating these relatively small implants within surgical incisions can be challenging or cumbersome for surgeons. Therefore, there is a long-standing need for improved implant connectors and related methods. Summary of the Invention

[0006] Some examples of this disclosure include an implant having a body having a rod receiving recess, wherein the body has a first side and a second side defining an opening into the rod receiving recess, and the rod receiving recess defines a central longitudinal rod axis extending between the openings of the first and second side sides. At least a portion of the rod receiving recess may be formed by an inner surface of the implant, wherein the inner surface defines two gripping grooves and the central longitudinal rod axis extending parallel to each other. Each gripping groove defines two edges, wherein the gripping groove intersects the inner surface, and the four edges of the two gripping grooves together define a circular radius about the central longitudinal rod axis. The implant also includes a retaining member configured to move relative to the body, apply a force to the rod in the rod receiving recess that may be perpendicular to the central longitudinal rod axis, and engage the rod against the four edges of the two gripping grooves. Additionally, the engagement of the four edges of the gripping grooves against the rod restricts rotational movement of the rod about the central longitudinal rod axis.

[0007] In some examples, the rod receiving recess defines a gap between two gripping grooves, the size of which is set and positioned to allow forces on the rod within the rod receiving recess, thereby allowing deflection of one or both of the edge and the rod, wherein the edge engages with the rod, and the deflection causes the rod to move into the gap. The inner surface of the rod receiving recess between the two gripping grooves can be positioned at a distance from the central longitudinal rod axis greater than the radius of the rod.

[0008] In some examples, the implant includes a compression member disposed in a cavity formed in the body, wherein the compression member has an inner surface defining at least a portion of a rod receiving recess, and wherein the inner surface of the compression member has two gripping grooves formed thereon. In some examples, the gripping grooves extend along the entire length of the inner surface of the rod receiving recess in the direction of the central longitudinal rod axis. In some examples, the gripping grooves are positioned relative to the central longitudinal rod axis opposite to a retaining member.

[0009] The rod receiving recess may be sized to receive an open end of the rod and sized to contact a closed end of the rod, wherein the gripping grooves are arranged symmetrically about an axis extending from the open end to the closed end. The body of the implant may define an inner surface forming the rod receiving recess. In some examples, the intersection between the gripping grooves and the inner surface defines a sharp edge.

[0010] The inner surface may define a groove intersecting at least one gripping recess, the intersection of which divides the edge of at least one gripping recess and defines four corners to resist translation of the rod along the central longitudinal rod axis when the rod engages with the edge. In some examples, the groove intersecting at least one gripping recess is oriented perpendicular to the gripping recess.

[0011] The gripping groove may be formed by protrusions extending from an inner surface. In some examples, at least one gripping groove defines an inner surface in which one or more protrusions are formed, the one or more protrusions extending to an edge arranged to contact the bar when the bar engages with the edge of the gripping groove.

[0012] In some examples, the implant includes a connector, and the rod receiving recess is a first rod receiving recess, with the body defining a second rod receiving recess, wherein one or both of the first and second rod receiving recesses have two gripping grooves. The body has a proximal end and a distal end defining a proximal-distal axis extending therebetween, wherein the retaining member is slidably disposed within a tunnel formed in the body and configured to translate relative to the body along the rod actuator axis.

[0013] In some examples, the second rod receiving recess is defined by a pair of spaced-apart arms of the body. The first rod receiving recess may open in a distal direction, and the second rod receiving recess may open in a proximal direction. The rod actuator axis may be substantially perpendicular to the proximal-distal axis. In some examples, the implant further includes a retaining screw threaded into the body to lock the first rod within the first rod receiving recess and the second rod within the second rod receiving recess.

[0014] Implants may include bone anchor assemblies, wherein the body has a receiving component of the bone anchor assembly and a retaining component having a fixing screw or locking element.

[0015] Another example of this disclosure is an implant having a body having a rod receiving recess, a gripping insert configured to be positioned in an open end of the receiving recess, and a retaining member configured to move relative to the body. The body has a first side and a second side defining an opening to the rod receiving recess, and the rod receiving recess defines a central longitudinal rod axis extending between the openings of the first and second sides. The gripping insert has an inner surface for contacting a rod disposed in the rod receiving recess, wherein the inner surface defines two gripping grooves extending parallel to each other and the central longitudinal rod axis, wherein each gripping groove defines two edges, wherein the gripping groove intersects the inner surface, and the four edges of the two gripping grooves together define a circular radius about the central longitudinal rod axis. The retaining member may be configured to apply force to the rod in the rod receiving recess and abut against the four edges of a rod engagement grip, wherein the engagement of the four edges of the gripping grooves with the rod restricts rotational movement of the rod about the central longitudinal rod axis.

[0016] Any of the above features or variations can be applied in a variety of different combinations to any particular embodiment of this disclosure. No specific combination is explicitly described merely to avoid redundancy within the scope of this invention. Attached Figure Description

[0017] Figure 1A This is a perspective view of a prior art bone anchor assembly;

[0018] Figure 1B yes Figure 1A Exploded view of the bone anchor assembly;

[0019] Figure 1C yes Figure 1A Top view of the bone anchor assembly;

[0020] Figure 1D yes Figure 1A A cross-sectional view of the bone anchor assembly;

[0021] Figure 2A This is a perspective view of existing technology connectors;

[0022] Figure 2B yes Figure 2A An exploded perspective view of the connectors, showing the first and second spinal rods;

[0023] Figure 2C It is in the first configuration Figure 2A A cross-sectional side view of the connector;

[0024] Figure 2D It is in the first configuration Figure 2A A top-section view of the connector;

[0025] Figure 2EIt is in the second configuration Figure 2A A cross-sectional side view of the connector;

[0026] Figure 2F It is in the second configuration Figure 2A A top-section view of the connector;

[0027] Figure 2G It is in the third configuration Figure 2A A cross-sectional side view of the connector;

[0028] Figure 2H It is in the third configuration Figure 2A A top-section view of the connector;

[0029] Figure 2I It connects to the first and second spinal rods. Figure 2A Side view of the connector;

[0030] Figure 2J yes Figure 2A A perspective view of the connector, showing the saddle;

[0031] Figure 2K yes Figure 2J An exploded perspective view of the connector and saddle, showing the first and second spinal rods;

[0032] Figure 2L It connects to the first and second spinal rods. Figure 2J A cross-sectional side view of the connector and saddle;

[0033] Figure 3A This is a cross-sectional view of one embodiment of a connector with a rod recess having two gripping grooves;

[0034] Figure 3B yes Figure 3A A cross-sectional view of the connector rod receiving recess;

[0035] Figure 3C yes Figure 3A A cross-sectional view of the gripping groove of the connector rod receiving recess;

[0036] Figure 4A This is a cross-sectional view of the recessed part of the rod receiving section in existing technology;

[0037] Figure 4B It is a cross-sectional view of one embodiment of a rod receiving recess with a V-shaped gripping groove;

[0038] Figure 4C yes Figure 4B A cross-sectional view of the rod receiving recess shows a comparison of the positions of the rod with and without the gripping groove;

[0039] Figure 4D This is a perspective view of the rod, showing when the rod is located... Figure 4B When the rod is received in the recessed part Figure 4B The contact line formed by the edges of the two gripping grooves;

[0040] Figure 4E It is a perspective view of the surface of one embodiment of a rod receiving recess with segmented gripping grooves;

[0041] Figure 4F yes Figure 4E A top view of the segmented gripping grooves;

[0042] Figure 4G Is with Figure 4E A schematic diagram of the contact points on the segmented gripping groove joint of the rod;

[0043] Figure 4H This is a perspective view of the rod's surface, showing when the rod is positioned... Figure 4E When the rod is received in the recessed part Figure 4E The contact line formed by the edges of the two segmented gripping grooves;

[0044] Figure 5A A cross-sectional view of one embodiment of a rod receiving recess with an alternatively shaped gripping groove;

[0045] Figure 5B It is a cross-sectional view of one embodiment of a rod receiving recess having a gripping groove formed by protrusions;

[0046] Figure 6A A cross-sectional view of one embodiment of a rod pusher having a rod receiving recess and a gripping groove;

[0047] Figure 6B A cross-sectional view of an alternative embodiment of a rod pusher with a rod receiving recess and a gripping groove;

[0048] Figure 6C This is a cross-sectional view of one embodiment of a rod receiving recess and a rod pusher, both having gripping grooves;

[0049] Figure 7A It is a cross-sectional view of one embodiment of a single gripping groove with an internal protrusion arranged to contact a bar perpendicular to the edge of the gripping groove in the gripping groove;

[0050] Figure 7B yes Figure 7A A top view of the gripping groove, showing the vertical edge of the internal protrusion;

[0051] Figure 7C yes Figure 7AA cross-sectional view of the grip groove, showing the inner protruding edge contacting the bar when it engages with the grip groove;

[0052] Figure 7D It is a perspective view of the rod, showing the structure formed by... Figure 7A The contact line formed by the edges of the two gripping grooves and the internal protrusions;

[0053] Figure 7E and Figure 7F It is a cross-sectional view of an embodiment of a single gripping groove with two different configurations of internal protrusions;

[0054] Figure 8A This is a cross-sectional view of the recessed part of the rod receiving section in existing technology;

[0055] Figure 8B It is a cross-sectional view of one embodiment of a rod receiving recess with two gripping grooves;

[0056] Figure 8C This is a cross-sectional view of one embodiment of a rod receiving recess and a rod engagement element having two gripping grooves;

[0057] Figure 8D This is a cross-sectional view of an alternative embodiment of a rod receiving recess and a rod engagement element having two gripping grooves;

[0058] Figure 9 A perspective view of one embodiment of a receiving member having a rod receiving recess with two gripping grooves;

[0059] Figure 10 It is a perspective view of one embodiment of a receiving member having a rod receiving recess with two circumferential grooves;

[0060] Figure 11A and Figure 11B It is a perspective view of one embodiment of a receiving member having a rod receiving recess with two segmented gripping grooves, the segmented gripping grooves being formed by the intersection of two gripping grooves and two circumferential grooves;

[0061] Figure 12 It is a perspective view of one embodiment of a receiving member having a rod receiving recess with two gripping grooves having multiple internal protrusions;

[0062] Figure 13 A cross-sectional view of one embodiment of a connector having a rod receiving recess with two gripping grooves;

[0063] Figure 14 This is a cross-sectional view of one embodiment of a bone anchor assembly with a compression member forming a rod receiving recess and a rod engagement element having two gripping grooves; and

[0064] Figure 15 It is a perspective view of the human spine with a fixation system attached to it. Detailed Implementation

[0065] This document discloses implants with gripping grooves and related methods. The implants may include connectors and receiver components of a bone anchor assembly. In some examples, the connector may include a low-profile portion to facilitate its use in space-constrained surgical applications. In some embodiments, the connector may include a bias rod actuator to allow the connector to "click" onto the rod and / or abut against the rod for "dragging," for example, for temporary positioning of the connector before locking.

[0066] Certain aspects of this disclosure provide increased torsional gripping capability of the implant on the rod. One example presented is a rod-to-rod connector, but the features can be applied to various spinal implants, such as screw heads for bone anchor assemblies. Aspects of this disclosure include single or multiple longitudinal grooves cut into the rod slot of the implant, which increases the additional contact line between the connector and the rod. In operation, when locked, a very small portion of the cross-sectional periphery of the rod wedges into the groove, thereby pressing both edges of the groove cut into the rod. Even if the rod cut point is not fully positioned relative to the groove, the groove provides edges, rather than flat surfaces, to abrade the rod and prevent further rotation if rotation might begin due to forces applied to the rod or connector. This micro-shearing of the material is the principle behind the increased torsional gripping capability.

[0067] Alternatively, these gripping grooves can be located on the surface of the rod, rather than on the connector, screw head, or receiving implant. Furthermore, the semi-circular gripping grooves can be other geometries, such as rectangular, right-angled or other angled, trapezoidal, etc.

[0068] The increased axial sliding (longitudinal bar sliding) gripping ability of the gripping groove is achieved by giving the groove a circumferential orientation relative to the bar. Longitudinal and circumferential gripping grooves can also be combined to increase torsional and axial resistance. The resulting feature can resemble a nail or corner.

[0069] Certain exemplary embodiments will now be described to provide a comprehensive understanding of the principles of the structure, function, manufacture, and use of the apparatuses and methods disclosed herein. One or more examples of these embodiments are illustrated in the accompanying drawings. It will be understood by those skilled in the art that the apparatuses and methods specifically described herein and illustrated in the accompanying drawings are non-limiting exemplary embodiments. Features shown or described in conjunction with one exemplary embodiment may be combined with features of other embodiments.

[0070] Figures 1A to 1DA prior art bone anchor assembly 10 is shown, comprising a bone anchor 12, a receiving member 14 for receiving a spinal fixation element (such as a spinal rod 22) to be coupled to the bone anchor 12, and a closure mechanism 16 for capturing the spinal fixation element within the receiving member 14 and securing the spinal fixation element relative to the receiving member 14. The bone anchor 12 includes a proximal head 18 and a distal axis 20 configured to engage bone. The receiving member 14 has a proximal end 26 and a distal end 32, the proximal end having a pair of spaced-apart arms 28A, 28B defining a recess 30 therebetween, and the distal end having an inner surface 35 for multiaxially positioning the proximal head 18 of the bone anchor 12 and a distal end surface 34 defining an opening through which at least a portion of the bone anchor 12 extends. The closing mechanism 16 can be positioned between and engaged with arms 28A and 28B to capture a spinal fixation element (e.g., spinal rod 22) within the receiving member 14 and fix the spinal fixation element relative to the receiving member 14.

[0071] The proximal head 18 of the bone anchor 12 is typically a truncated spherical shape having a flat proximal surface 36 and a generally spherical distal surface 38. An exemplified bone anchor assembly is a multiaxial bone anchor designed for later implantation into a pedicle or lateral mass of a vertebra. The proximal head 18 of the bone anchor 12 is arranged in a ball-and-socket configuration to engage the distal end 32 of the receiver member 14, wherein the proximal head 18 and the distal axis 20 are pivotable relative to the receiver member 14. The mating surfaces within the distal surface 38 of the proximal head 18 of the bone anchor 12 and the distal end 32 of the receiver member 14 can have any shape that facilitates this arrangement, including, for example, spherical (as shown), annular, conical, truncated conical, and any combination of these shapes.

[0072] The distal shaft 20 of the bone anchor 12 may be configured to engage bone and, in an illustrated embodiment, includes an external bone engagement thread 40. The thread type for the distal shaft 20 may be selected, including the number of threads, pitch, major and minor diameters, and thread shape, to facilitate engagement with bone. Exemplary thread types are disclosed in U.S. Patent Application Publication No. 2011 / 0288599, filed May 18, 2011, and U.S. Provisional Patent Application Serial No. 61 / 527,389, filed August 25, 2011, both of which are incorporated herein by reference. The distal shaft 20 may also include other structures for engaging bone, including hooks. The distal shaft 20 of the bone anchor 12 may be hollow, having a central channel or cannula extending the length of the bone anchor to facilitate delivery of the bone anchor via a guidewire, for example, in minimally invasive surgery. Other components of the bone anchor assembly, including, for example, the closure member 16, the receiving member 14, and the compression member 60 (described below), may be hollow or otherwise have openings to allow delivery via a guidewire or to allow insertion of an actuator to manipulate the bone anchor. The distal shaft 20 may also include one or more sidewall openings or perforations communicating with the cannula to allow bone ingrowth or to allow the dispensing of bone cement or other materials via the bone anchor 12. The sidewall openings may extend radially from the cannula through the sidewall of the distal shaft 20. Exemplary systems for delivering bone cement to the bone anchor assembly 10 and alternative bone anchor configurations facilitating cement delivery are described in U.S. Patent Application Publication No. 2010 / 0114174, filed October 29, 2009, which is incorporated herein by reference. The distal axis 20 of the bone anchor 12 may also be coated with a material that allows bone growth (e.g., hydroxyapatite), and the bone anchor assembly 10 may be partially or completely coated with an anti-infective material (e.g., dichlorophenoxychlorophenol).

[0073] The proximal end 26 of the receiving member 14 includes a pair of spaced-apart arms 28A, 28B defining a U-shaped recess 30 therebetween for receiving a spinal fixation element, such as a spinal rod 22. Each of the arms 28A, 28B may extend from the distal end 32 of the receiving member 14 to a free end. The outer surface of each of the arms 28A, 28B may include features such as recesses, pits, notches, protrusions, etc., to facilitate connection of the receiving member 14 to an instrument. For example, the outer surface of each arm 28A, 28B may include an arcuate groove at the respective free end of the arm. Such grooves are described in more detail in U.S. Patent No. 7,179,261, published February 20, 2007, which is incorporated herein by reference. At least a portion of the proximal end surface 48 of the receiving member 12 defines a plane Y. The receiving member 14 has a central longitudinal axis L.

[0074] The distal end 32 of the receiving member 14 includes a distal end surface 34, which is generally an annular shape defining a circular opening through which at least a portion of the bone anchor 12 extends. For example, the distal axis 20 of the bone anchor 12 may extend through the opening. At least a portion of the distal end surface 34 defines a plane X.

[0075] The bone anchor 12 can be selectively fixed relative to the receiving member 14. Before fixation, the bone anchor 12 can move relative to the receiving member 14 within an angled cone, which is typically defined by the geometry of the distal end 32 of the receiving member and the proximal head 18 of the bone anchor 12. The bone anchor shown is an off-center multiaxial screw, wherein the angled cone is offset in one direction. In this way, the bone anchor 12 can move relative to the receiving member 14 in at least a first direction. Figure 1D As indicated by arrow A, this first direction is at a first angle C relative to the central longitudinal axis L of the receiving member 14. The bone anchor 12 can also move in at least a second direction. Figure 1D Arrow B indicates that the first angle C is at a second angle D relative to the longitudinal axis L. The first angle C is greater than the second angle D, and therefore, the axis 20 of the bone anchor 12 can move further in the direction indicated by arrow A. The distal axis 20 of the bone anchor 12 defines a neutral axis 48 relative to the receiving member 14. The neutral axis 48 may be perpendicular to the plane X defined by the distal end surface 34 and intersects the center point of the opening on the distal end surface 34 through which the distal axis 20 of the bone anchor 12 extends. The neutral axis 48 may be oriented at an angle to the central longitudinal axis L of the receiving member 14. The plane Y defined by at least a portion of the proximal end surface 48 of the receiving member 14 intersects the plane X defined by at least a portion of the distal end surface 34 of the receiving member 12. The proximal end 26 of the receiving member 14 may include a proximal first hole 50 coaxial with a first central longitudinal axis N (which coincides with longitudinal axis L) and a distal second hole 52 coaxial with a second central longitudinal axis M (which coincides with neutral axis 48), and the first central longitudinal axis N and the second central longitudinal axis M may intersect each other. The angle between plane X and plane Y and the angle between axis L and axis M can be selected to provide a desired offset angular angle. Examples of offset multiaxial screws are described in more detail in U.S. Patent No. 6,974,460, published December 13, 2005, and U.S. Patent No. 6,736,820, published May 18, 2004, both of which are incorporated herein by reference. Alternatively, the bone anchor assembly may be a conventional (non-offset) multiaxial screw, wherein the bone anchor pivots by the same amount in each direction and has a neutral axis coinciding with the central longitudinal axis L of the receiving member.

[0076] A spinal fixation element (e.g., spinal rod 22) may directly contact the proximal head 18 of the bone anchor 12 or may contact an intermediate element, such as a compression member 60. The compression member 60 may be located within the receiving member 14 and inserted between the spinal rod 22 and the proximal head 18 of the bone anchor 12 to compress the distal outer surface 38 of the proximal head 18, thereby directly and securely engaging the distal inner surface of the receiving member 14. The proximal portion of the compression member 60 may include a pair of spaced-apart arms 62A and 62B defining a U-shaped seat 64 for receiving the spinal rod 22. The distal portion of the compression member 60 may include a sidewall having an inner cylindrical surface 67 connected to an outer cylindrical surface 68 via a distally facing surface 66.

[0077] At least a portion of the distal surface 66 of the compression member 60 can be shaped as a negative of the proximal portion 18 of the bone anchor 20, with the distal surface 66 abutting against this negative when the compression member 60 is fully inserted into the receiving member 14. Therefore, the contact area between the distal surface 66 of the compression member 60 and the proximal head 18 is maximized when the axis 20 of the bone anchor 12 is oriented along the longitudinal axis L. When the angle of the axis 20 relative to the longitudinal axis L is not zero, the contact area between the distal surface 66 of the compression member 60 and the head 18 can be reduced, thereby increasing the risk of slippage of the bone anchor 12 relative to the receiving member 14.

[0078] like Figure 1B As best shown, the compression member 60 is configured to slide freely within the recess 30 of the receiving member 14 along the longitudinal axis L. To secure the compression member 60 within the receiving member 14, the compression member 60 can be configured to mate with the receiving member, for example, by mechanically deforming a portion of the compression member 60 against the receiving member 14. In the illustrated embodiment, opposing holes formed on the arms 62A, 62B of the compression member 60 are aligned with holes formed on the arms 62A, 62B of the receiving member 14, such that opposing pins can be inserted through channels defined by the holes to compress or "forge" the compression member 60 against the receiving member 14. The forging process prevents the compression member 60 from subsequently being removed from the receiving member 14.

[0079] The proximal end 26 of the receiving member 14 may be configured to receive and engage a closure mechanism 16 positioned between and engaging the arms 28A and 28B of the receiving member 14. The closure mechanism 16 may be configured to capture a spinal fixation element, such as a spinal rod 22, within the receiving member 14 to fix the spinal rod 22 relative to the receiving member 14 and to fix the bone anchor 12 relative to the receiving member 14. The closure mechanism 16 may be a single fixation screw having external threads for engaging internal threads 42 disposed on the arms 28A, 28B of the receiving member 14. However, in the illustrated embodiment, the closure mechanism 16 includes an external fixation screw 70 positioned between and engaging the arms 28A, 28B of the receiving member 14 and an internal fixation screw 72 positioned within the external fixation screw 70. The external fixation screw 70 is operable to act on a compression member 60 to fix the bone anchor 12 relative to the receiving member 14. The internal fixation screw 72 is operable to act on the spinal rod 22 to fix the spinal rod 22 relative to the receiving member 14. In this manner, the closure mechanism 16 allows the bone anchor 12 to be fixed relative to the receiving member 14, independently of the spinal rod 22. Specifically, the external fixation screw 70 can engage the proximal end surfaces of the arms 62A, 62B of the compression member 60 to force the distally facing surface 66 of the compression member 60 into contact with the proximal head 18 of the bone anchor 12, which in turn forces the distal surface 38 of the proximal head 18 to be fixedly engaged with the distal inner surface of the receiving member 14. The internal fixation screw 72 can engage the spinal rod 22 to force the spinal rod 22 to be fixedly engaged with the rod seat 64 of the compression member 60.

[0080] The external fixing screw 70 includes a first external thread 74 for engaging complementary internal threads 42 on the arms 28A, 28B of the receiving member 14. The external fixing screw 74 includes a central channel 96 extending from the top surface 98 of the external fixing screw 74 to the bottom surface 100 of the external fixing screw 74 for receiving the internal fixing screw 72. The central channel 96 may include an internal thread 102 for engaging the complementary external thread 104 on the internal fixing screw 72. The thread type for the internal thread 102 and the external thread 104 can be selected, including the number of threads, pitch, major and minor diameters, and thread shape, to facilitate connection between components and transfer of desired axial tightening force. The top surface 98 of the external fixing screw 74 may have one or more drive features to facilitate rotation and advance of the external fixing screw 74 relative to the receiving member 14. The illustrated external fixing screw 74 includes drive features in the form of a plurality of cutouts 106 spaced around the periphery of the top surface 98. The internal fixation screw 104 may include a drive feature for receiving an instrument to rotate and advance the internal fixation screw 72 relative to the external fixation screw 74. The internal fixation screw 104 shown includes a drive feature in the form of a central channel 108 having a plurality of spaced, longitudinally oriented cutouts for engaging complementary features on the instrument.

[0081] The bone anchor assembly 10 can be used with a spinal fixation element, such as a rigid spinal rod 22. The various components of the bone anchor assembly disclosed herein, as well as the spinal rod 22, can be made of various materials, including titanium, titanium alloys, stainless steel, cobalt-chromium, PEEK, or other materials suitable for rigid fixation. In other embodiments, the spinal fixation element can be a dynamic stabilizing member that allows controlled movement between the vertebrae of the device.

[0082] In use, bone can be prepared to receive the bone anchor assembly 10, typically by drilling a hole in the bone, the hole size being appropriately set to receive the bone anchor 12. If not yet completed, the bone anchor assembly 10 can be assembled, which may include assembling the bone anchor 12 and the receiving member 14 such that the distal shaft 20 extends through an opening on the distal end 32 of the receiving member 14, and the proximal head 18 of the bone anchor 12 is received in the distal end 32 of the receiving member 14. A driving tool can be adapted to the bone anchor 12 to drive the bone anchor 12 into the hole prepared in the bone. A compression member 60 can be located within the receiving member 14, such that the arms 62A, 62B of the compression member are aligned with the arms 28A, 28B of the receiving member 14, and the lower surface of the compression member 14 contacts the proximal head 18 of the bone anchor 12. A spinal fixation element (e.g., a spinal rod 22) can be positioned in the recess 30 of the receiving member 14. The closure mechanism 16 can engage the internal threads 42 provided on the arms 28A, 28B of the receiving member 14. Torque can be applied to the external fixation screw 70 to move it within the recess 30 using a tool that can engage multiple cuts 106 on the upward-facing surface of the external fixation screw 70 to force the compression member 60 onto the proximal head 18 of the bone anchor 12. Torque can then be applied to the internal fixation screw 72 to move it relative to the external fixation screw 70, such that the internal fixation screw contacts the spinal rod 22 and can fix the spinal rod 22, for example, relative to the receiving member 14 and the bone anchor 12.

[0083] One or more embodiments of the bone anchor assembly of the present invention are described below. Except as shown below, the structure, operation, and use of these embodiments are similar to or the same as the structure, operation, and use of the bone anchor assembly 10 described above. Therefore, for the sake of brevity, detailed descriptions of the structure, operation, and use are omitted here. Figures 3A to 12 It shows something similar to that made by Figure 1B Various embodiments of the rod receiving recess shown in the illustration, including the recess formed by the receiving member 14 and / or the compression member 60, but with a gripping recess or feature formed on the inner surface of the rod receiving recess for use with... Figure 1B The bone anchor shown grips the cylindrical rod 22 with greater friction compared to the receiving component 14 and / or compression component 60. Figures 3A to 12 The rod receiving recess shown can be used with Figures 1A to 1DIt can be used with the bone anchor assembly shown, or with a variety of other bone anchor assemblies known in the art. Figure 8C and Figure 8D A rod receiving recess with a locking member is shown, which is arranged to abut against a cylindrical rod 22 to compress an insert having a gripping recess or feature thereon. Figure 8C and Figure 8D The insert shown can be used with Figures 1A to 1D The bone anchor assembly shown can be used together with, or with, various other bone anchor assemblies known in the art, and can be secured by a locking mechanism (such as...). Figures 1A to 1D The external fixing screw 70 or internal fixing screw 72 shown is pressed onto the cylindrical rod 22.

[0084] Figures 2A to 2L A prior art connector 200 with a conventional configuration for securing a rod to a connector 200 is shown. As shown, the connector 200 may include a body 202 defining a first rod receiving recess 204 and a second rod receiving recess 206, a rod actuator 208, a biasing element or spring wire 212, and a locking element or retaining screw 216. The rod actuator 208 may be configured to translate laterally within the body 202 and may be biased by the spring wire 212 in the direction that pushes the rod actuator into the first rod R1 disposed in the first rod receiving recess 204. The retaining screw 216 may be tightened to lock the connector 200 to both the first rod R1 and the second rod R2 disposed in the second rod receiving recess 206. Thus, the illustrated connector 200 may allow the first rod R1 and the second rod R2 to be locked to the connector in one step. The connector 200 may include one or more low-profile portions to facilitate use in tight spaces. For example, a first rod receiving recess 204 may be formed in a portion of the connector body 202 with a reduced profile, for example, to fit between bone anchors in adjacent segments of the implanted cervical vertebrae.

[0085] The body 202 may include a proximal end 202p and a distal end 202d defining a proximal-distal axis A1. The proximal end 202p of the body 202 may include a pair of spaced-apart arms 218, 220 defining a second rod receiving recess 206 therebetween. A rod R2 disposed in the second rod receiving recess 206 may have a central longitudinal rod axis A2. The second rod receiving recess 206 may be open in the proximal direction such that the rod R2 can be inserted into the recess by moving the rod distally relative to the connector 200. Each of the arms 218, 220 may extend from the distal portion 202d of the body 202 to a free end. The outer surface of each of the arms 218, 220 may include features (not shown), such as recesses, indentations, notches, protrusions, etc., to facilitate coupling of the connector 200 to various instruments. For example, the outer surface of each arm 218, 220 may include an arcuate groove at the corresponding free end of the arm for attaching the connector 200 to an extension tower or retractor. Arms 218, 220 may include or be coupled to extension tabs or reduction tabs (not shown) extending proximally from the body 202 to functionally extend the length of the arms 218, 220. The extension tabs may facilitate the insertion and repositioning of rods or other implants, as well as the insertion and locking of the retaining screw 216. The extension tabs may be configured to disengage from or otherwise separate from the arms 218, 220. The inner surface of each arm 218, 220 may be configured to mate with the retaining screw 216. For example, the inner surface of arms 218, 220 may include threads corresponding to the external threads formed on the retaining screw 216. Thus, rotation of the retaining screw 216 relative to the body 202 about axis A1 effectively translates the retaining screw axially relative to the body along axis A1.

[0086] The distal end 202d of the main body 202 may define a tunnel 228 in which a rod actuator 208 may be disposed. The tunnel 228 may extend along the rod actuator axis A3 between a second rod receiving recess 206 and a first rod receiving recess 204. The rod actuator 208 may be configured to translate within the tunnel 228 along axis A3. Axis A3 may be perpendicular to or substantially perpendicular to axis A1. Axis A3 may also be perpendicular to or substantially perpendicular to axis A2. The tunnel 228 may have a negative shape that substantially resembles the external shape of the rod actuator 208. A through-hole 224 may be formed on the main body 202 such that the through-hole intersects with the tunnel 228. The through-hole 224 may extend perpendicular to or substantially perpendicular to axis A3. The through-hole 224 may be sized to receive a spring wire 212 therein, as further described below. The through-hole 224 may be open at both ends, or closed at one or both ends.

[0087] The main body 202 may include a cantilevered airfoil portion 230 defining a first rod receiving recess 204. The rod R1 disposed in the first rod receiving recess 204 may have a central longitudinal rod axis A4. Axis A4 may be parallel to axis A2 as shown, or may be perpendicular to or angled relative to axis A2. The airfoil portion 230 may extend radially outward from a second arm 220 of the main body 202. The airfoil portion 230 may have a width 230W and a height 230H. The ratio of the width 230W to the diameter of the first rod receiving recess 204 (or the rod R1 disposed therein) may be less than about 1.5:1, less than about 2:1, and / or less than about 3:1. The ratio of the height 230H to the diameter of the first rod receiving recess 204 (or the rod R1 disposed therein) may be less than about 0.5:1, less than about 1:1, and / or less than about 2:1. The height 230H can be less than about 5 mm, less than about 4 mm, and / or less than about 3 mm. The first rod receiving recess 204 can be open in the distal direction, such that the rod R1 can be inserted into the recess by moving the connector 200 distally relative to the rod. The first rod receiving recess 204 can be open in the proximal direction, for example, by flipping the wing portion 230 and forming it such that it extends from the distal portion of the body 202, or by extending in the lateral direction.

[0088] As described above, the lever actuator 208 can be slidably disposed within the tunnel 228 of the body 202 and can be configured to translate relative to the body along axis A3. The lever actuator 208 may include a first bearing surface 244A configured to contact and abut against a first lever R1 disposed in a first lever receiving recess 204. The bearing surface 244A may extend at an oblique angle relative to the longitudinal axis of the lever actuator 208, such that the bearing surface is obliquely inclined. The bearing surface 244A may be planar as shown, or may be convex, concave, pointed, sharpened, etc. For example, the bearing surface 244A may be concave and may define a cylindrical section such that the bearing surface matches or approximates the profile of the cylindrical lever R1 disposed in the first lever receiving recess 204. The lever actuator 208 may include a second bearing surface 244B configured to contact and abut against a second lever R2 disposed in a second lever receiving recess 206. The bearing surface 244B may extend at an oblique angle relative to the longitudinal axis of the rod pusher 208, such that the bearing surface is inclined. The bearing surface 244B may be planar as shown, or it may be convex, concave, pointed, sharpened, etc. For example, the bearing surface 244B may be concave and may define a cylindrical section such that the bearing surface matches or approximates the profile of the cylindrical rod R2 disposed in the second rod receiving recess 206.

[0089] The lever actuator 208 may include a through-hole 226. The through-hole 226 may extend perpendicularly to or substantially perpendicular to axis A3. The through-hole 226 may be sized to receive a spring wire 212 therein. In at least some positions relative to the body 202, the through-hole 226 of the lever actuator 208 may be aligned with a through-hole 224 of the body, such that the spring wire 212 extends through both through-holes 224 and 226. Figure 2D , Figure 2F and Figure 2H As best shown, the through-hole 226 may include a middle portion and opposing end portions. The middle portion of the through-hole 226 may approximate the size of the spring wire 212. For example, the middle portion may be cylindrical and may have a diameter substantially equal to the diameter of the spring wire 212. The end portions of the through-hole 226 may be elongated or may otherwise have a size greater than the diameter of the spring wire 212 to allow the rod pusher 208 to translate along axis A3 and to accommodate the bending radius of the spring wire 212 during such translation.

[0090] A biasing element can be configured to bias the rod pusher 208 toward the first rod receiving recess 204. In the illustrated view, the biasing element is a cylindrical spring wire 212. The spring wire 212 can be formed of an elastic material such that when deformed from a straight line, the spring wire tends to bend back to its straight resting configuration. Therefore, when deformed by the movement of the rod pusher 208, the spring wire 212 can apply a force to the interior of the through-hole 226 to push the rod pusher 208 toward the first rod receiving recess 204. Although a straight cylindrical spring wire 212 is shown, various other biasing elements, such as non-straight or non-cylindrical wires, leaf springs, spring clips, wave springs, coil springs, etc., can be used alternatively or additionally. The biasing element may be omitted. For example, the rod pusher 208 may float freely within the tunnel 228, or it may be held by a pin or other retaining feature without biasing toward the first rod receiving recess 204.

[0091] The retaining screw 216 may include an external thread configured to engage with an internal thread formed on the arms 218, 220 of the body 202 to allow the retaining screw to advance or retract relative to the body along axis A1 by rotating the retaining screw about axis A1. The retaining screw 216 may include a drive interface 248 configured to receive an actuator for applying rotational force to the retaining screw about axis A1. The distal surface of the retaining screw 216 may be configured to contact and abut against a rod R2 disposed in a second rod receiving recess 206 to lock the rod to the connector 200. When tightened against the rod R2, the retaining screw 216 prevents the rod from translating relative to the connector 200 along axis A2 and / or rotating relative to the connector about axis A2. Although the retaining screw 216 is shown, it should be understood that other locking elements such as a closed cap that advances and locks by a quarter turn, a closed cap that slides laterally without rotating, a nut screwed onto the outside of the connector 200, etc., may be used alternatively or additionally.

[0092] The operation of connector 200 is in Figures 2C to 2H The diagram is shown schematically.

[0093] like Figure 2C and Figure 2D As shown, the connector 200 can have a static configuration in which no rod is disposed in the first rod receiving recess 204 or the second rod receiving recess 206. In this configuration, the biasing force of the spring wire 212 can cause the rod pusher 208 to slide toward the first rod receiving recess 204.

[0094] In the static configuration, the airfoil portion 230 of the main body 202 and the free end of the rod actuator 208 can define an orifice 250, which is smaller than the diameter of the first rod R1 to be connected by the connector 200. Therefore, as Figure 2E and Figure 2F As shown, when rod R1 is inserted into the first rod receiving recess 204, the rod abuts against rod pusher 208 to move connector 200 out of its stationary configuration. The insertion of rod R1 moves rod pusher 208 along axis A3, thereby deforming spring wire 212 from its stationary state. Since the largest cross-sectional portion of rod R1 is located in orifice 250, rod pusher 208 can be moved to its furthest distance from the first rod receiving recess 204.

[0095] like Figure 2G and Figure 2HAs shown, once the largest cross-sectional portion of rod R1 clears the orifice 250 when the rod is located in the first rod receiving recess 204, the biasing force of the spring wire 212 can cause the rod pusher 208 to move rearward along axis A3 toward the first rod receiving recess. This movement can at least partially close the orifice 250 around rod R1 to capture the rod in the first rod receiving recess 204. The biasing force of the spring wire 212 can resist the reverse movement of the rod pusher 208, and thus resist the connector 200 from disengaging from the first rod R1. The geometry of the connector 200 can be selected such that the spring wire 212 deforms from its rest state when rod R1 is fully located in the first rod receiving recess 204. Therefore, before tightening the retaining screw 216 and / or before the second rod R2 is positioned in the connector 200, the spring wire 212 can press against rod R1 against the rod pusher 208 to provide a frictional or dragging effect.

[0096] The second rod R2 can be positioned in the second rod receiving recess 206, and the retaining screw 216 can be tightened to lock the connector 200 to the first rod R1 and the second rod R2. When the retaining screw 216 is tightened, the second rod R2 can press against the second bearing surface 244B of the rod pusher 208, pushing the rod pusher towards the first rod receiving recess 204 and firmly contacting the rod R1. When the retaining screw 216 is tightened, the connector 200 can be locked to the first rod R1 and the second rod R2 to resist or prevent translation of the rods R1 and R2 relative to the connector along axes A2 and A4, and to resist or prevent rotation of the rods R1 and R2 relative to the connector about axes A2 and A4.

[0097] like Figure 2I As shown, the second rod receiving recess 206 can be shaped to facilitate contact between the second rod R2 and the second bearing surface 244B of the rod pusher 208. In other words, the recess 206 can be shaped to reduce or eliminate the risk that the second rod R2 will only bear pressure on the bottom plate of the recess 206 when the fixing screw 216 is tightened, without applying sufficient force to the bearing surface 244B. As shown, the recess 206 may include a release device aligned with the end of the tunnel 228, such that the rod pusher 208 protrudes into the recess. Therefore, the recess 206 may be asymmetrical about axis A1 and may deviate from a symmetrical U-shape. When the rod R2 reaches its lowest point in the recess 206, the central longitudinal axis A2 of the rod may deviate from axis A1. When the rod is fully positioned, the central longitudinal axis of the rod R2 is in Figure 2I The axis is shown as A5. The recess 206 can be configured such that when the rod R2 is located within the recess 206, the rod translates distally along axis A1 and laterally along axis A3.

[0098] like Figures 2J to 2LAs shown, connector 200 may include a saddle 210. A saddle 210 may be included in addition to or as an alternative to the asymmetrical recess 206. Saddle 210 may be positioned within a cavity 222 formed on body 202. Saddle 210 may be generally cylindrical, with a first arm 232 and a second arm 234 extending proximally to their respective free ends. The first arm 232 and the second arm 234 may be aligned with the first arm 218 and the second arm 220 of body 202 such that the recess defined therebetween aligns with the second rod receiving recess 206. Thus, when the second rod R2 is disposed in the second rod receiving recess 206, the rod may be simultaneously supported between the arms 232, 234 of saddle 210 and the arms 218, 220 of body 202. Saddle 210 may include a ramped bearing surface 240 configured to contact and abut against a second bearing surface 244B of rod actuator 208. The bearing surface 240 may extend at an oblique angle relative to axis A1. The bearing surface 240 may be planar as shown, or it may be convex, concave, pointed, sharpened, etc. In operation, for example, by tightening the retaining screw 216 downwards onto the saddle or downwards onto the rod R2 disposed in the saddle, a force applied along direction A1 to the saddle 210 may cause the saddle 210 to translate distally relative to the body 202, and cause the bearing surface 240 to rise obliquely along the bearing surface 244B of the rod pusher 208, thereby pushing the rod pusher towards the first rod receiving recess 204 along axis A3. Therefore, tightening the retaining screw 216 can effectively lock rods R1 and R2 simultaneously to the connector 200. The saddle 210 allows rods of different diameters to be locked in the second rod receiving recess 206, while still ensuring that sufficient force is applied to the rod pusher 208 to lock the first rod R1 regardless of the diameter of the second rod R2.

[0099] Sometimes, arms 232, 234 may extend proximally beyond the maximum dimension of rod R2, and the retaining screw 216 may include an external screw configured to abut the proximal surface of the arm. An internal retaining screw may be threaded into the external retaining screw. Therefore, the external retaining screw can be tightened first to press firmly against the saddle 210 and lock the first rod R1 in the first rod receiving recess 204. Then, the internal retaining screw can be tightened to press firmly against the second rod R2 and lock the second rod in the second rod receiving recess 206. Thus, the dual retaining screws facilitate independent locking of the first rod R1 and the second rod R2 to the connector 200. Although... Figures 2J to 2L Not shown, but the connector 200 including the saddle 210 may also include a biasing element as described above for biasing the rod pusher 208 toward the first rod receiving recess 204.

[0100] Therefore, connector 200 can be used to connect the first spinal rod R1 to the second spinal rod R2. While this document generally describes the use of connector 200 with the first and second spinal rods, it should be understood that the connector can alternatively be configured for use with other types of orthopedic hardware, whether implanted or external. For example, one or both halves of connector 200 can be modified to connect various other components to each other (e.g., connecting rods to plates, plates to plates, rods to cables, cables to cables, etc.).

[0101] Connector 200 can provide various benefits to the user and / or patient. For example, when connector 200 “clicks” onto the first rod R1, the biased rod actuator 208 can provide tactile feedback, assuring the user that the rod has been successfully attached before tightening the connector. The biased rod actuator 208 can also apply friction or “dragging” to rod R1 before locking the retaining screw 216, helping to hold the connector in place and prevent “floating” while still allowing free movement when the user intends. As a further example, the low-profile geometry of the wing portion 230 of connector 200 can allow the connector to be used in space-constrained surgical areas (e.g., in the cervical region of the spine). In an exemplary method, the wing portion 230 of connector 200 can hook onto the first rod R1 at a location between the two bone anchors to which the rod is attached, which are implanted in adjacent vertebral segments of the cervical spine. As yet another example, connector 200 can facilitate simultaneous and / or single-step locking of the first rod R1 and the second rod R2. This allows connector 200 to lock onto the two rods R1, R2 with minimal steps. In other cases, connector 200 can facilitate independent locking of rods R1, R2, for example, using saddle 210 and double retaining screws.

[0102] Exemplary connectors and implants are disclosed in U.S. Patent Application Publication No. 2017 / 0333088, filed October 4, 2016, and U.S. Patent Application Publication No. 2017 / 0333087, filed May 18, 2016, both of which are incorporated herein by reference.

[0103] Figure 3AThis is a cross-sectional view of a connector having a rod recess with two gripping grooves. As shown, the connector 300 may include a body 202 defining a first rod receiving recess 304, a second rod receiving recess 306, and a rod actuator 308. The rod actuator 308 may be configured to translate laterally within the body 302 and may be biased in a direction that pushes the rod actuator 308 into a first rod R1 disposed in the first rod receiving recess 304. A retaining screw 216 may be tightened to lock the connector 300 to both the first rod R1 and the second rod R2 disposed in the second rod receiving recess 306. Thus, the illustrated connector 300 allows the first rod R1 and the second rod R2 to be locked to the connector in one step (e.g., ...). Figures 2A to 2L (As shown). Connector 300 may include one or more low-profile portions to facilitate use in tight spaces. For example, a first rod receiving recess 304 may be formed in a portion of connector body 202 with a reduced profile, for example, to fit between bone anchors implanted in adjacent segments of the cervical spine.

[0104] Body 302 may include a proximal end and a distal end defining the proximal-distal axis A1, such as Figure 2B As shown. The proximal end of the body 202 may include a pair of spaced-apart arms 318, 320, which define a second rod receiving recess 306 therebetween. The rod R2 disposed in the second rod receiving recess 306 may have a central longitudinal rod axis A2, as shown. Figure 2B As shown. The second rod receiving recess 306 may open in the proximal direction, allowing the rod R2 to be inserted into the recess by moving the rod distally relative to the connector 200. Each of the arms 318, 320 may extend from the distal portion of the body 302 to a free end. The outer surface of each of the arms 318, 320 may include features (not shown), such as recesses, notches, notches, protrusions, etc., to facilitate coupling of the connector 300 to various instruments. For example, the outer surface of each arm 318, 320 may include an arcuate groove at the corresponding free end of the arm for attaching the connector 300 to an extension tower or retractor. Arms 318, 320 may include or be coupled to extension tabs or reduction tabs (not shown) extending proximally from the body 302 to functionally extend the length of arms 218, 220. Extension tabs may facilitate insertion and reduction of rods or other implants, as well as insertion and locking of fixation screws 216, such as Figure 2B As shown. The extension tab can be configured to detach from or otherwise separate from arms 218, 220. The inner surface of each of arms 318, 320 can be configured to mate with the retaining screw 216. For example, the inner surface of arms 318, 320 may include threads corresponding to the external threads formed on the retaining screw 316. Thus, rotation of the retaining screw 316 relative to the body 302 about axis A1 can effectively cause the retaining screw to translate axially relative to the body along axis A1.

[0105] The main body 302 may include a cantilevered airfoil portion 330 that defines the first rod receiving recess 304. For example... Figure 2B As shown, the rod R1 disposed in the first rod receiving recess 304 may have a central longitudinal rod axis A4. Axis A4 may be parallel to axis A2 as shown, or may be perpendicular to or angled relative to axis A2. The wing-shaped portion 330 may extend radially outward from the second arm 320 of the body 302. The first rod receiving recess 304 may open in the distal direction, allowing the rod R1 to be inserted into the recess by moving the connector 300 distally relative to the rod. The first rod receiving recess 304 may open in the proximal direction, for example, by flipping the wing-shaped portion 330 and forming it such that it extends from the distal portion of the body 302, or in the lateral direction.

[0106] The lever actuator 308 can be slidably disposed within the tunnel 328 of the main body 302, and can be configured to translate relative to the main body along axis A3, such as... Figure 2B As shown. The lever actuator 308 may include a first bearing surface 344A configured to contact and abut a first lever R1 disposed in a first lever receiving recess 304. The bearing surface 344A may extend at an oblique angle relative to the longitudinal axis of the lever actuator 308, such that the bearing surface is inclined. The bearing surface 344A may be planar as shown, or it may be convex, concave, pointed, sharpened, etc. For example, the bearing surface 344A may be concave and may define a cylindrical section such that the bearing surface matches or approximates the profile of the cylindrical lever R1 disposed in the first lever receiving recess 204. The lever actuator 308 may include a second bearing surface 344B configured to contact and abut a second lever R2 disposed in a second lever receiving recess 306. The bearing surface 344B may extend at an oblique angle relative to the longitudinal axis of the lever actuator 208, such that the bearing surface is inclined. The bearing surface 344B can be planar as shown, or it can be convex, concave, pointed, sharp, etc. For example, the bearing surface 344B can be concave and can define a cylindrical section such that the bearing surface matches or approximates the contour of the cylindrical rod R2 provided in the second rod receiving recess 306.

[0107] Figure 3A A first rod receiving recess 304 is shown, which includes two gripping grooves 301 opposite to the bearing surface 344A. The gripping grooves 301 are formed as recesses in the inner surface of the first rod receiving recess 304, such as... Figure 3B This is shown more clearly in the text.

[0108] Figure 3B yes Figure 3AA cross-sectional view of the connector rod receiving recess 304. Figure 3B The gripping grooves 301 each define two edges 312, 313, 322, and 323, which are configured to contact the surface of a cylindrical rod R1 disposed in a first rod receiving recess 304. The gripping grooves 301 extend along axis A4, and the dimensions and shape of the first rod receiving recess 304 are set such that the side of the cylindrical rod R1 facing the gripping grooves 301 is pushed by a rod pusher 308 to contact the edges 312, 313, 322, and 323, such that additional force applied to the cylindrical rod R1 by the rod pusher 308 further engages the cylindrical rod R1 against the edges 312, 313, 322, and 323. This can be achieved, for example, by setting the dimensions and shape of the inner surface of the rod receiving recess 304 and the position of the gripping groove 301 such that the edges 312, 313, 322, 323 define the radius of a roughly matching cylindrical rod R1 about axis A4, and when the cylindrical rod R1 is pushed into the rod receiving recess 304, half of the cylindrical rod R1 opposite the first bearing surface 344A of the rod pusher contacts the rod receiving recess 304 only at the engagement edges 312, 313, as... Figure 3C It is shown in more detail below.

[0109] Figure 3C yes Figure 3A A cross-sectional view of the gripping groove 301 of the rod receiving recess 304 of the connector 300. Figure 3C A cylindrical rod R1 (solid line) is shown disposed in a rod receiving recess 304 and in contact with edges 312, 313, such that a small portion of the outer surface of the cylindrical rod R1 is received within each gripping groove 301. This illustrated configuration shows the cylindrical rod R1 contacting the rod receiving recess 304 at four contact points, in contrast to the prior art rod receiving recess 204 which does not have gripping grooves. This prior art configuration... Figure 3C The position shown is that of cylindrical rod R1', which covers cylindrical rod R1. The position of cylindrical rod R1' (dashed line) corresponds to positioning cylindrical rod R1' in rod receiving recess 304 without gripping groove 301, as shown. Figure 4A This is shown more clearly in the text. Figure 3C The radius 398 of the cylindrical rod R1 and the distance 399 from each edge 312, 313 to the central longitudinal axis A4 of the rod receiving recess 304 are shown to be approximately the same.

[0110] Figure 4A This is a cross-sectional view of the recessed portion of the rod receiving section in existing technology. Figure 4AA cylindrical rod R1 is shown disposed in a prior art rod receiving recess 204 without a gripping groove. In this configuration, the cylindrical rod R1 contacts the inner surface of the rod receiving recess 204 at two points P1, P2. In operation, these two points P1, P2 can define a parallel contact line along axis A4 (e.g., along the surface of the cylindrical rod R1 that contacts the inner surface of the rod receiving recess 204). The specific interface between the cylindrical rod R1 and the rod receiving recess 204 at these points P1, P2 is a curved surface (e.g., the cylindrical rod R1) relative to a flat or angled surface (e.g., the rod receiving recess 204). Through this engagement, the rotation of the cylindrical rod R1 about axis A4 and the translation of the cylindrical rod R1 in the A4 direction are limited by the force applied by the surface of the rod receiving recess 204 against the cylindrical rod R1. This force depends on the force applied by the rod pusher 208 and the frictional force between the cylindrical rod R1 and the surface of the rod receiving recess 204. The radius 498 of the cylindrical rod R1 is shown relative to the central axis R of the cylindrical rod R1.

[0111] like Figure 4B As shown, various aspects of this disclosure provide improved retention of the cylindrical rod R1 in the rod receiving recess 304. Figure 4B This is a cross-sectional view of a rod receiving recess 308 with a V-shaped gripping groove 401. This shape of the gripping groove 401 defines edges 412, 413, which are positioned to contact the surface of the cylindrical rod R1 at points E1-E4. That is, the V-shaped gripping groove 401 is formed on the surface of the rod receiving recess 304 such that edges 412, 413 define four points on a circle with a radius approximately the same as that of the cylindrical rod R1. In operation, the cylindrical rod R1 abuts against the four edges 412, 413, and a rod pusher 308 applies a force 488 to the cylindrical rod R1, which presses the surface of the cylindrical rod R1 against the edges 412, 413. Figure 4A Compared to existing surface-to-surface bonding techniques, the curved surface of the cylindrical rod R1 is pressed against sharp edges 412, 413 (e.g., corners or apexes, forming edges with sufficiently small radii or thicknesses to be deformable by the cylindrical rod R1, or to deform the surface of the cylindrical rod R1 to allow it to be pushed into the gripping groove 401). This causes rotation of the cylindrical rod R1 as it presses against the four edges 412, 413 requires micro-shearing at contact points E1-E4. Therefore, the gripping groove 401 restricts rotation of the cylindrical rod R1 within the rod receiving recess 304 in a manner requiring material property failure, allowing movement between the edges 412, 413 and the cylindrical rod R1. Thus, for equal forces applied to the cylindrical rod R1 by the rod pusher 308, the gripping groove 401 can withstand higher torques on the cylindrical rod R1 about axis A4 before movement occurs.

[0112] In some cases, to ensure engagement between the cylindrical rod R1 and the edges 412, 413, a recess 450 is formed in the rod receiving recess 304, such that the movement of the cylindrical rod R1 against the edges 412, 413, driven by the rod pusher 308, is not interrupted by the cylindrical rod R1 contacting the inner surface of the rod receiving recess 308. This configuration allows the initial push of the cylindrical rod R1 against the edges 412, 413 to produce some deformation at the contact points E1-E4 (e.g., deformation of the material of the cylindrical rod R1, or of any or both of the edges 412, 413), such that any initial rotation of the cylindrical rod R1 induces further material deformation at the contact points E1-E4.

[0113] Although Figure 4B A body 302 with two gripping grooves 401 is shown. In some cases, the body 302 has only one gripping groove 401, for example, in which the single gripping groove 401 is positioned relative to the clamping force vector such that the force vector 488 and the center of the gripping groove 401 intersect the central axis A4 of the rod R1.

[0114] Figure 4B It is also shown that the radius 498 of the cylindrical rod R1 and the distance 499 of each edge 412, 413 from the central longitudinal axis A4 of the rod receiving recess 304 can be approximately the same to allow the surface of the cylindrical rod R1 to uniformly contact the edges 412, 413. In this case, the central axis R of the cylindrical rod R1 is concentric with the central longitudinal axis A4 of the rod receiving recess 304.

[0115] Figure 4C yes Figure 4B A cross-sectional view of the rod receiving recess 304 shows a comparison of the positions of the cylindrical rod R1 with and without the gripping groove 401. Figure 4C As shown Figure 4B The position of the cylindrical rod R1 engaging with the gripping groove 401 is shown, as is the position of the same cylindrical rod R1 (as shown by the dashed line R1') positioned in the rod receiving recess 204 without the gripping groove 401. Compared to the position of the cylindrical rod R1' abutting against the rod receiving recess 204, the cylindrical rod R1 in the rod receiving recess 304 with the gripping groove 401 is positioned further in the recess 450 because a small portion of the surface of the cylindrical rod R1 is received in the gripping groove 401 to allow the edges 412, 413 to fully contact the surface of the cylindrical rod R1.

[0116] Figure 4D This is a perspective view of the cylindrical rod R1, showing the contact lines E1-E4 formed by the edges 412, 413 of the two gripping grooves 401 when the cylindrical rod R1 is positioned in the rod receiving recess 304. Figure 4B (As shown). Figure 4DThe resulting contact between a rod receiving recess 304 having a gripping groove 401 spanning the length of a cylindrical rod R1 is shown. This allows the cylindrical rod R1 to be pressed into the edges 412, 413 along the contact lines E1-E4, such that the force applied to the cylindrical rod R1 is not interrupted by the contact between the cylindrical rod R1 and the rod receiving recess 304, except along the contact lines E1-E4. In some cases, and as explained in more detail below, additional contact points and lines between the cylindrical rod R1 and the rod receiving recess 304 are within the scope of this disclosure; however, such additional contact still allows a sufficient portion of the force applied to the cylindrical rod R1 to be directed along the contact lines E1-E4 to the edges 412, 413, thereby creating conditions that resist rotation of the cylindrical rod R1 by requiring material deformation of one or both of the cylindrical rod R1 and the edges 412, 413 along the contact lines E1-E4. Figure 4D The contact lines E1-E4 are shown to be oriented to resist rotation of the cylindrical rod R1 in the clockwise CW and counterclockwise CCW directions.

[0117] Figure 4E This is a perspective view of the surface 410 of the rod receiving recess 304 having segmented gripping grooves 403. The segmented gripping grooves 403 are formed when the gripping grooves 401 intersect with one or more recesses or grooves 408. Figure 4E A segmented gripping groove 403 formed by a gripping groove 401 is shown, which intersects with two recesses 408 oriented at right angles to the gripping groove 401. However, in some embodiments, other angles are possible, such that one or more recesses or grooves 408 are transverse to the gripping groove 401 (e.g., inclined to, etc.). The intersection of the gripping groove 401 and the grooves 408 creates a break along the length of the cylindrical rod R1 at the edges 412, 413 of the gripping groove, as... Figure 4F As shown, these are now referred to as segmented edges 412 and 413.

[0118] Figure 4F yes Figure 4E A top view of the segmented gripping groove. In operation, this is achieved by creating point edges 480 (e.g., small corners when the rod is pushed into the groove, and each point edge 480 forming a small corner that contacts the rod R1), as... Figure 4G As shown, it engages the surface of the cylindrical rod R1 and enables the segmented edges 412, 413 to apply force to the cylindrical rod R1 in the A4 direction. The segmented edges 412, 413 are used to limit the movement of the cylindrical rod R1 along the length of the segmented gripping groove 403 (i.e., translation along the axis A4). Figure 4G Is with Figure 4E A schematic diagram of the contact points F1-F4 on the cylindrical rod R1 that are engaged with the segmented gripping groove 403. Figure 4GThe diagram illustrates that when the cylindrical rod R1 is pressed into engagement with the segmented gripping groove 403, the resulting contact lines F1, F2 of the segmented edges 412, 413 are also segmented. In the case of engagement between the cylindrical rod R1 and the segmented edges 412, 413, point edges or small corners 480 define the transition between points on the cylindrical rod R1 where the segmented edges 412, 413 contact and do not contact the cylindrical rod R1. For example, if the material properties of the cylindrical rod R1 and the segmented edges 412, 413 are selected such that the surface of the cylindrical rod R1 deforms upon contact with the segmented edges 412, 413, then the point edges 480 together resist translation of the rod along the segmented gripping groove 403 (i.e., translation along axis A4), because such movement causes two of the four illustrated point edges 480 to be driven into the undeformed region of the surface of the cylindrical rod R1. Therefore, the segmented gripping groove 403 can resist both rotation and translation of the cylindrical rod R1 within the rod receiving recess 403, such as Figure 4F As shown.

[0119] Figure 4H This is a perspective view of the surface of the cylindrical rod R1, showing the segmented contact lines F1-F4 formed by the edges of the two segmented gripping grooves 403 when the cylindrical rod R1 is positioned in the rod receiving recess 304. Clockwise CW and counterclockwise CCW rotations of the cylindrical rod R1 are resisted by the segmented gripping grooves 403 in the same manner as described above with respect to the non-segmented gripping groove 401, and translation of the cylindrical rod R1 is resisted by the point edge 480 generated between the segmented edges 412, 413.

[0120] Although Figure 3A A gripping groove 301 with a cylindrical shape is shown, and Figure 4B A V-shaped gripping groove 401 is shown, but other shapes are also possible. For example, Figure 5A It is a cross-sectional view of the rod receiving recess 403 with a rectangular gripping groove 501, wherein the edges 512, 513 are right angles. Figures 3A to 5A The gripping grooves 301, 401, and 501 are shown as recesses formed on the inner surface of the rod receiving recess 304. However, the gripping grooves can also be formed by protrusions 540 extending from the inner surface of the rod receiving recess 304, such as... Figure 5B As shown.

[0121] Figures 3A to 5B The diagram shows gripping grooves 301, 401, and 501 formed on the wing-shaped portion 330 of the main body 302, wherein the rod actuator 308 is arranged to apply force to the cylindrical rod R1 to drive the cylindrical rod R1 against the gripping grooves 301, 401, and 501; however, other configurations are also possible. For example, Figure 6AThis is a cross-sectional view of the rod receiving recess 304 of the rod pusher 308 with a gripping groove 601. As shown, the gripping groove 601 defines four contact points E1-E4 that contact the edges 612, 613 of the cylindrical rod R1, these contact points defining a circle with approximately the same radius as the cylindrical rod R1. Figure 6A In this configuration, the surface of the rod receiving recess opposite to the rod actuator 308 defines a curved surface 651 that contacts the cylindrical rod R1 to apply force against the force applied to the cylindrical rod R1 through the edges 612, 613 of the gripping groove 601 of the rod actuator 308. During operation, the gripping groove 601 of the rod actuator 308 functions in the same manner as the gripping grooves 301, 401, and 501 described above. Figure 6B It is a cross-sectional view of a rod receiving recess 304 with a recess 450 and a rod pusher 308 with a gripping groove 601. Figure 6C The diagram shows both the rod receiving recess 304, the gripping groove 501, and the rod actuator 308 with the gripping groove 601. In this configuration, the position of the cylindrical rod R1 is height-constrained by the gripping grooves 501 and 601 because all eight contact points E1-E8 engage with the surface of the cylindrical rod R1. However, in some cases, the positional tolerance of the eight contact points E1-E8 decreases upon initial contact with the cylindrical rod R1, such that once sufficient force is applied to fully engage the cylindrical rod R1 around the eight contact points E1-E8, the cylindrical rod R1 is height-constrained.

[0122] Figure 7A This is a cross-sectional view of a single gripping groove 501 with an internal protrusion 710 arranged to contact the surface of the cylindrical rod R1 between the edges 512, 513 of the gripping groove 501. To increase the constraint of the cylindrical rod R1 in the translational direction (i.e., along axis A4), additional gripping features can be included within the gripping groove 501 to provide translational constraint with minimal to negligible effect on the rotational constraint provided by the edges 512, 513. Figure 7A In the gripping groove 501, there are one or more protrusions 701 along the length of the gripping groove 501. The inner protrusions 710 extend toward the cylindrical rod R1 and include features such as end edges 711 that are positioned to contact the cylindrical rod R1 when the cylindrical rod R1 engages with the edges 512, 513 of the gripping groove 501. Figure 7A An internal protrusion 710 is shown, wherein edge 711 contacts cylindrical rod R1 along contact line L1, which is perpendicular to contact lines E1, E1 generated by edges 512, 513. In operation, the position and shape of edge 711 in the gripping groove 501 can be configured to alter the strength of contact line L1 between cylindrical rod R1 and edge 711 when cylindrical rod R1 contacts edges 512, 513, such as... Figure 7Dand Figure 7E It is shown in more detail below.

[0123] Figure 7B yes Figure 7A A top view of the gripping groove 501 shows that the vertical edges 711 of the two internal protrusions 710 create two parallel contact lines L1, L2 on the cylindrical rod R1. Figure 7C yes Figure 7A A cross-sectional view of the gripping groove 501 shows that when the rod engages with the gripping groove 501, the edge 711 of the inner protrusion 710 contacts the cylindrical rod R1.

[0124] Figure 7D This is a perspective view of the cylindrical rod R1, showing contact lines E1-E4 formed by the edges 512, 513 of the two gripping grooves 501 and contact lines L1-L4 formed by the two internal protrusions 710 in each gripping groove 501. In operation, contact lines E1-E4 formed by the edges 512, 513 resist rotation of the cylindrical rod R1 in the clockwise (CW) and counterclockwise (CCW) directions, and contact lines L1-L4 formed by the two internal protrusions 710 resist translation of the cylindrical rod R1 in the A4 direction.

[0125] Figure 7E and Figure 7F It is a cross-sectional view of a single gripping groove 501 with two different edge configurations of internal protrusions 710. Figure 7E In the first configuration shown, the inner protrusion 710 extends to a flat edge 711, which defines a contact line L1 with the cylindrical rod R1. This contact line extends as the cylindrical rod R1 is pressed against edges 512, 513. Because the initial size of the contact line L1 is small, the resistance to the movement of the cylindrical rod R1 into the gripping groove 510 is minimized, thereby ensuring a positive engagement between the cylindrical rod R1 and the inner protrusion 710. Figure 7F In the second configuration shown, the inner protrusion 710 has a curved edge 712, which is shaped to initially contact the cylindrical rod R1 with a longer contact line L1, in order to increase the translational constraint of the cylindrical rod R1 upon initial contact with edges 512, 513. The resulting strength of the constraint of the two different edge shapes 711, 712 can depend on the material properties of the cylindrical rod R1, edges 512, 513 and the inner protrusion 710, as well as the position of edges 711, 712 relative to edges 512, 513. For example, if the cylindrical rod R1 is made of a metal softer than the metal of the inner protrusion 710, the edges 711, 712 can extend closer to the radius of the edges 512, 513 (i.e., the intended position of the cylindrical rod R1), such that the cylindrical rod R1 first contacts the edges 711, 712, and the edges 711, 712 are driven into the surface of the cylindrical rod R1 as the cylindrical rod R1 engages with the edges 512, 513.

[0126] Figure 8A This is a cross-sectional view of a prior art rod receiving recess 206, such as that of the receiving member 14 of a bone anchor assembly 10 or the body 202 of a connector 200. A cylindrical rod R1 is disposed in the rod receiving recess 206 and contacts the inner surface of the rod receiving recess 206 at two points P1 and P2 along the axis of the rod receiving recess 206. Locking elements or fixing screws 104 and 216 contact the cylindrical rod R1 at point P3 and apply force to push the cylindrical rod R1 into the rod receiving recess 206 and abut against the two points P1 and P2.

[0127] Figure 8B It is a cross-sectional view of a rod receiving recess 306 having two gripping grooves 801, which are formed as parallel recesses in the inner surface of the rod receiving recess 306. Figure 8B A cylindrical rod R1 is shown disposed in a rod receiving recess 306 and engages with the edges 812, 813 of a gripping groove 801. Threaded locking elements or retaining screws 104, 216 are arranged to secure the cylindrical rod R1 in the rod receiving recess 306 by applying force to the cylindrical rod R1 to push it against the edges 812, 813 of the gripping groove 801. Figure 8B The position of the cylindrical rod R1 in the rod receiving recess 306 if the gripping groove 801 is missing is also shown, which is indicated as R1'. The difference between the position of R1' and the cylindrical rod R1 with the gripping groove 801 is due to the gripping groove 801 defining edges 812, 813 at four locations along the inner surface of the rod receiving recess 306. These four locations have radii approximately the same as those of the cylindrical rod R1 from the central axis of the rod receiving recess 306, thereby allowing the central axis of the cylindrical rod R1 to be concentric with the axis defined by the equiradial locations of the edges 812, 813. Otherwise, the gripping groove 801 is positioned to allow the cylindrical rod R1 to rest against all four edges 812, 813 when pushed into the rod receiving recess 306 by the locking element or the fixing screws 104, 216. In some cases, the rod receiving recess 306 is defined in a recess or gap 850 (as defined by the gripping groove 801) below the designed position of the cylindrical rod R1, so as to allow the cylindrical rod R1 to be pushed further into the rod receiving recess 306 by means of the retaining screws 104, 216, resulting in increased pressure on the edges 812, 813.

[0128] Figure 8C and Figure 8DAn embodiment is shown in which the gripping groove 801 is positioned on an insert 816, which is driven against a cylindrical rod R1 in a rod receiving recess 306. The insert 816 is driven against the cylindrical rod R1 by retaining screws 104, 216, but does not rotate with the retaining screws 104, 216 because the insert 816 is shaped to extend the gripping groove 801 along the length of the cylindrical rod R1. The insert 816 may include a pin 817 received by the retaining screws 104, 216 to engage the groove 801 with the body 302 (in which the retaining screws 104, 216 are screwed, not shown) to allow the body 302 to resist rotation of the cylindrical rod R1 via engagement of the cylindrical rod R1 with the gripping groove 801. Figure 8C A rod receiving recess 306 with a circular section is shown to provide surface contact with the cylindrical rod R1, thereby resisting the force of the insert 816. Figure 8D A rod receiving recess 306 with a tapered closed end and a gap 850 is shown, thereby providing two contact lines P1, P2 with the cylindrical rod R1 to resist the force of the insert 816.

[0129] Figure 9 It is a perspective view of a receiving member 902 having a rod receiving recess 904, wherein two gripping grooves 801 are formed. Figure 10 It is a perspective view of a receiving member 902 having a rod receiving recess 904, wherein two circumferential grooves 1020 are cut into rod receiving recesses 904 perpendicular to the central longitudinal axis of the receiving recess 904.

[0130] Figure 11A and Figure 11B It is a perspective view of a receiving member 902 having a rod receiving recess 904, wherein two segmented gripping grooves 403 are formed therein by the intersection of two gripping grooves 801 and two circumferential grooves 1020. Figure 11B The dotted edge 480 generated by the segmented gripping groove 403 is shown. Figure 12 It is a perspective view of a receiving member 902 having a rod receiving recess 906, wherein the gripping groove 801 has a plurality of internal protrusions 710 formed therein. Figures 9 to 11B The receiving member 902 and the rod receiving recess 904 may be, for example, the body 302 of the connector 300, or the receiving member 14 of the bone anchor assembly 10, or any other implant configured to be fixed to a rod, cable or other spinal fixation element.

[0131] Figure 13 This is an illustration of a connector 300 with a saddle 301 defining a rod receiving recess with a gripping groove 1301. Figure 13In the connector 300, the cylindrical rod R1 is secured to the receiving member 14 by engaging with a rod receiving recess formed by the inner surface of the saddle 301, and the inner surface of the saddle 60 includes two gripping grooves 1301 configured to grip the cylindrical rod R1 when the locking screw 216 applies force on the cylindrical rod R1 to push the cylindrical rod R1 into the gripping grooves 1301.

[0132] Figure 14 This is an illustration of a bone anchor assembly 10, which has a compression member 60 defining a rod receiving recess with a gripping groove 1401. Figure 14 In the bone anchor assembly, a cylindrical rod R1 is secured to the receiving member 14 by contacting a compression member 60 disposed in the receiving member, wherein the inner surface of the forming rod receiving recess of the compression member 60 includes a gripping groove 1401 that contacts the cylindrical rod R1. In operation, an internal fixing screw 102 applies force to the cylindrical rod R1 to push the cylindrical rod R1 into the gripping groove 1401.

[0133] Figure 15 It is a perspective view of the human spine with a fixation system attached to it.

[0134] The following describes exemplary methods of using the bone anchors and connectors disclosed herein. In some cases, the bone anchor and connector are each secured to one or two rods to bridge, for example, between constructs in the cervical and thoracic regions of a patient's spine. The bone anchor and connector can be secured to the rod using a rod receiving recess with a gripping groove to increase resistance to movement of the rod, connector, and bone anchor relative to each other.

[0135] The procedure can be initiated by creating an opening or percutaneous incision in the patient to access the target site. The target site can be one or more vertebrae, long bones, or multiple sections of long bones, or any other bone or non-bone structure of the patient. Figure 15 As shown, the target area can be multiple vertebrae in the patient's cervical and thoracic spine.

[0136] Bone anchors can be driven into one or more vertebrae, and spinal rods can be attached to them using known techniques. In the example shown, eight bone anchors S1-S8 are used to connect bilateral spinal rods R1, R2 to four adjacent vertebrae V1-V4. Additionally, four bone anchors S9-S12 are used to connect bilateral rods R3, R4 to the next two adjacent vertebrae V5-V6. Rods R1 and R2 can be connected to rods R3 and R4 respectively using four connectors C1-C4 (e.g., connector 300) of the type described herein, and bone anchors S1-S8 can be connected to rods R1-R4 using receivers of the type described herein (e.g., receiver 902).

[0137] As shown in the figure, the low-profile nature of connectors C1-C4 allows them to be mounted on adjacent vertebral segments on the same rod (e.g., between V2 / V3 and V3 / V4). Also as shown, connectors C1-C4 can be connected to rods R1, R2 mounted between bone anchors in adjacent vertebral segments.

[0138] Connectors C1-C4 can receive rods in corresponding rod receiving recesses, wherein the rod receiving recesses have gripping grooves to secure the connector to the rods R1, R2, thereby providing improved rotation and, in some cases, providing axial constraint on the movement of the rods R1, R2 relative to the connector.

[0139] Connectors C1-C4 may include independent locking features, such that they can lock to rods R1 and R2 before locking to rods R3 and R4, or vice versa.

[0140] Connectors C1-C4 may include a single-step locking feature, allowing them to lock simultaneously to their respective levers. For example, connector C1 can lock simultaneously to levers R1 and R3.

[0141] All rods R1-R4, connectors C1-C4, and bone anchors S1-S12 can be installed in a single surgery.

[0142] Alternatively, rods R1, R2 and bone anchors S1-S8 may be installed in a previous surgery, and the current surgery may be a revision surgery in which rods R3, R4, connectors C1-C4 and bone anchors S9-S12 are installed to extend the previously installed construct to the additional segment.

[0143] Connectors C1-C4 can be attached to positioning rods R1-R4 such that they are substantially parallel to each other and substantially located in the common coronal plane as shown. Connectors C1-C4 can also be rotated 90 degrees from the orientation shown so that positioning rods are aligned with R1, R3 and R2, R4 such that they are substantially located in the respective common longitudinal plane.

[0144] The above steps can be repeated to install additional rods and / or connectors at the same or different vertebral segments. Final tightening or other adjustments to the construct can be made, and the surgery can be completed and the incision closed using known techniques.

[0145] 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.

[0146] While the methods shown and described herein generally involve attaching a spinal rod to multiple vertebrae, it should be understood that the connectors and methods described herein can be used with a variety of other types of fixation or stabilization hardware in any bone, in non-bone tissue, or in non-biological or non-tissue objects. The connectors disclosed herein can be fully implanted or used as part of an external fixation or stabilization system. The devices and methods disclosed herein can be used in minimally invasive and / or open surgery.

[0147] The device disclosed herein and its various components 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 a radiopaque material to facilitate visualization under fluoroscopic examination and other imaging techniques, or of a radiopaque material so as not to interfere with the visualization of other structures. Exemplary radiopaque materials include carbon fibers and high-strength polymers.

[0148] Although specific implementation plans have been described above, it should be understood that various variations are possible within the substance and scope of the described concept.

Claims

1. An implant comprising: The body has a rod receiving recess, a first side and a second side defining an opening to the rod receiving recess, the rod receiving recess defining a central longitudinal rod axis extending between the openings of the first side and the second side, wherein at least a portion of the rod receiving recess is formed by an inner surface of the implant, the inner surface defining two gripping grooves extending parallel to each other and the central longitudinal rod axis. Each gripping groove defines two edges, wherein the gripping groove intersects the inner surface, and the four edges of the two gripping grooves together define a circular radius around the central longitudinal rod axis; as well as A retaining member, configured to move relative to the body, applies a force perpendicular to the central longitudinal axis of the rod to the rod receiving recess, and engages the rod against the four edges of the two gripping grooves. The four edges of the gripping groove abut against the engagement of the rod to limit rotational movement of the rod about the central longitudinal rod axis. The rod receiving recess defines a gap between the two gripping grooves, the gap being sized and positioned to allow forces on the rod in the rod receiving recess, thereby allowing one or both of the edge and the rod to deflect, wherein the edge engages the rod, and the deflection causes the rod to move into the gap.

2. The implant according to claim 1, wherein, The inner surface of the rod receiving recess between the two gripping grooves is positioned such that the distance from the central longitudinal rod axis is greater than the radius of the rod.

3. The implant of claim 1, the implant comprising a compression member disposed in a cavity formed in the body, the compression member having an inner surface defining at least a portion of the rod receiving recess, the inner surface of the compression member having the two gripping grooves formed on the inner surface.

4. The implant according to claim 1, wherein, The gripping groove extends along the entire length of the inner surface of the rod receiving recess in the direction of the central longitudinal rod axis.

5. The implant according to claim 1, wherein, The gripping groove is positioned relative to the central longitudinal rod axis and opposite to the retaining member.

6. The implant according to claim 1, wherein, The rod receiving recess is sized to receive the open end of the rod and sized to contact the closed end of the rod, wherein the gripping groove is arranged symmetrically about an axis extending from the open end to the closed end.

7. The implant according to claim 1, wherein, The body of the implant defines the inner surface that forms the rod receiving recess.

8. The implant according to claim 1, wherein, The intersection between the gripping groove and the inner surface defines a sharp edge.

9. The implant according to claim 1, wherein, The inner surface defines a groove that intersects with at least one gripping groove, the intersection of which divides the edge of the at least one gripping groove and defines four corners to resist translation of the rod along the central longitudinal rod axis when the rod engages with the edge.

10. The implant according to claim 8, wherein, The groove intersecting at least one gripping groove is oriented perpendicular to the gripping groove.

11. The implant according to claim 1, wherein, At least one gripping groove defines an inner surface in which one or more protrusions are formed, the one or more protrusions extending to an edge arranged to contact the rod when the rod engages with the edge of the gripping groove.

12. The implant according to claim 1, wherein, The gripping groove is formed by protrusions extending from the inner surface.

13. The implant according to claim 1, wherein, The implant includes a connector, and the rod receiving recess is a first rod receiving recess, the body defines a second rod receiving recess, wherein one or both of the first rod receiving recess and the second rod receiving recess have the two gripping grooves, the body has a proximal end and a distal end, the proximal end and the distal end defining a proximal-distal axis extending between the proximal end and the distal end; The retaining member is slidably disposed within a tunnel formed in the body and is configured to translate relative to the body along the axis of the rod pusher.

14. The implant according to claim 13, wherein, The second rod receiving recess is defined by a pair of spaced-apart arms of the body.

15. The implant according to claim 13, wherein, The first rod receiving recess is open in the distal direction, and the second rod receiving recess is open in the proximal direction.

16. The implant according to claim 13, wherein, The axis of the rod actuator is substantially perpendicular to the proximal-distal axis.

17. The implant of claim 13, wherein the connector further comprises a retaining screw, the retaining screw being threadedly received in the body to lock the first rod in the first rod receiving recess and to lock the second rod in the second rod receiving recess.

18. The implant according to claim 1, wherein, The implant includes a bone anchor assembly, the body includes a receiving component of the bone anchor assembly, and the retaining component includes a fixing screw or locking element.

19. An implant comprising: A body having a rod receiving recess, the body having a first side and a second side defining an opening to the rod receiving recess, the rod receiving recess defining a central longitudinal rod axis extending between the openings of the first side and the second side; A gripping insert is configured to be positioned in the open end of the rod receiving recess and defined for contacting an inner surface of a rod disposed in the rod receiving recess, the inner surface defining two gripping grooves extending parallel to each other and the central longitudinal rod axis, wherein each gripping groove defines two edges, wherein the gripping groove intersects the inner surface, and the four edges of the two gripping grooves together define a circular radius around the central longitudinal rod axis; as well as A retaining member, configured to move relative to the body, applies force to the rod in the rod receiving recess and abuts against the rod to engage the four edges of the gripping groove. The four edges of the gripping groove abut against the engagement of the rod to limit rotational movement of the rod about the central longitudinal rod axis. The rod receiving recess defines a gap between the two gripping grooves, the gap being sized and positioned to allow forces on the rod in the rod receiving recess, thereby allowing one or both of the edge and the rod to deflect, wherein the edge engages the rod, and the deflection causes the rod to move into the gap.

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