Patent Description:
At times, a surgeon may wish to connect two spinal fixation rods, for example, in a generally end-to-end configuration. It may be desired to make a connection between two rods to, in effect, make a lengthened rod. However, often the two rods to be connected are not in generally planar, parallel alignment.

<CIT> discloses a spinal connector including a first seat having a first opening for coupling to a first spinal connecting member along a first longitudinal axis and a second seat having a second opening for coupling to a second spinal connecting member along a second longitudinal axis. The second longitudinal axis is substantially coaxial to the first longitudinal axis for connecting the first and second connecting members end to end. The spinal connector also includes a ball enclosure rotatably received in the second opening of the second seat. The ball enclosure defines a bore along the second longitudinal axis and articulates with the second opening for allowing change of orientation of the second connecting member relative to the first connecting member.

Accordingly, there remains an unmet need for an apparatus, system, and method to provide for improved spinal fixation rod connectors.

The present disclosure will be more readily understood from a detailed description of some example embodiments taken in conjunction with the following figures:.

Described herein are example embodiments of spinal fixation rod connectors useful for connecting spinal fixation rods in orthopedic procedures that include spinal fixation. In general, the polyaxial connectors described in the examples herein include structure and features that permit a spinal fixation rod to be secured in an opening of the connector in a range of orientations. That is, a spinal fixation rod can be secured in the polyaxial connectors described herein such that at least one of the rods, and, for descriptive purposes, its respective central axis, can be oriented in a range of directions in a plane, the range of directions defining an arc of, in an embodiment, up to and including <NUM> degrees or more. Thus, polyaxial connectors can connect the ends of connected spinal fixation rods in one or both of a non-planar and a non-parallel relationship.

Referring to <FIG>, a representative rod-to-rod spinal fixation rod connector <NUM> is shown. As shown, a first spinal fixation rod <NUM> and a second spinal fixation rod <NUM> can be joined by being inserted into respective openings in the spinal fixation rod connector <NUM> and secured by a first set screw <NUM> and a second set screw <NUM>, respectively. Each opening in the spinal fixation rod connector is a cylindrical opening into which the spinal fixation rod can be inserted for securement.

Referring to <FIG>, there is shown another representative rod-to-rod spinal fixation rod connector <NUM> in use with pedicle screws <NUM> that are screwed into pedicle bones <NUM> in a spinal fixation configuration. As shown, a first spinal fixation rod <NUM> and a second spinal fixation rod <NUM> can be joined by being inserted into respective openings the rod-to-rod spinal fixation rod connector <NUM> and secured by a first set screw <NUM> and a second set screw <NUM>, respectively. Each opening in the spinal fixation rod connector is a cylindrical opening into which the spinal fixation rod can be inserted for securement.

The representative rod-to-rod spinal fixation rod connectors shown in <FIG> connect the ends of the connected rods in a generally planar (e.g., in the plane of the paper for <FIG>) and parallel relationship. Often, a surgeon may wish to connect rod ends that are not in a planar or parallel relationship.

Referring now to <FIG>, there is shown an example embodiment of a polyaxial connector <NUM> having a connector body <NUM>. Features and benefits of the polyaxial connector <NUM> can be understood with reference to two imaginary intersecting, orthogonal planes: an imaginary first reference plane <NUM> and an imaginary second reference plane <NUM>. The imaginary first reference plane <NUM> divides the polyaxial connector body into two portions, a first body portion <NUM> and a second body portion <NUM>. The first body portion <NUM> can be adjoined to the second body portion <NUM>. By "adjoined" is meant the first body portion <NUM> and the second body portion <NUM> lie next to, or are in contact, with one another. In example embodiments the connector body <NUM> can be unitary, such that the first body portion <NUM> and the second body portion <NUM> are simply two sides of a unitary, single-piece body member. In other embodiments, the first body portion <NUM> and the second body portion <NUM> can each be discrete parts that can be joined to form a connector body <NUM>.

The imaginary first reference plane <NUM> can be considered a vertical plane for a polyaxial connector <NUM> as depicted in <FIG>. Likewise, the imaginary second reference plane <NUM> can considered a horizontal plane for a polyaxial connector <NUM> as depicted in <FIG>. In general, the terms "vertical," "horizontal," "above," "below," and the like are used herein with respect to the orientation of features as depicted in the FIGS. Each of the imaginary first reference plane <NUM> and the imaginary second reference plane <NUM> can bisect the connector into two parts, which parts can be, in an example, equal halves. However, the terms "intersecting," "bisect," "bisecting," "divides" and the like are intended to mean that the imaginary planes described herein for the purposes of describing the structure of the polyaxial connector <NUM> can divide the polyaxial connector <NUM> into portions which may not have equal size and shape, but which can also be two portions that are equal, i.e., two halves, as depicted in <FIG>.

The polyaxial connector <NUM> has an external surface <NUM>, the external surface defining a plurality of openings that pass through at least a portion of the polyaxial connector <NUM>. The external surface <NUM> on the first body portion <NUM> defines openings to a first spinal rod passage <NUM> defining a first spinal rod passage axis <NUM>. The first spinal rod passage <NUM> passes completely through the connector body <NUM> and serves as a passage for connecting a first spinal rod (not shown in <FIG>, but as shown in <FIG>), the first spinal rod having a first spinal rod axis that can be, when connected, co-axial with the first spinal rod passage axis <NUM>. The external surface <NUM> on the first body portion <NUM> defines a first internally threaded set screw opening <NUM> defining a first set screw axis <NUM>. A first set screw (not shown in <FIG>, but as shown in <FIG>) can be screwed into the first internally threaded set screw opening <NUM> to engage and tighten on the first spinal rod inside the first spinal rod passage <NUM>. Once inserted and secured, it can be understood that the end of the first spinal rod can be secured in a fixed position with reference to the imaginary first reference plane <NUM> and the imaginary second reference plane <NUM>. In an example, once inserted and secured, the end of the first spinal rod can be secured in a fixed position parallel to one or both of the imaginary first reference plane <NUM> and the imaginary second reference plane <NUM>. In an embodiment, the first spinal rod passage axis <NUM> and the first set screw axis <NUM> are co-planar.

Referring again to <FIG>, and <FIG> and <FIG> which are each cross-sectional views of the polyaxial connector <NUM> shown in <FIG>, the external surface <NUM> on the second body portion <NUM> defines openings to a second spinal rod passage <NUM> defining a second spinal rod passage axis <NUM>. The second spinal rod passage <NUM> passes completely through the connector body <NUM> and serves as a passage for connecting a second spinal rod (not shown in <FIG>, but as shown in <FIG>), the second spinal rod having a second spinal rod axis that can be, when connected, co-axial with the second spinal rod passage axis <NUM>. The external surface <NUM> on the second body portion <NUM> defines a second internally threaded set screw opening <NUM> defining a second set screw axis <NUM>. The second spinal rod passage <NUM> has a first passage surface <NUM> opposite the second internally threaded set screw opening <NUM>, against which is pressed the forces introduced by screwing down the set screw. The second spinal rod can be inserted in the second spinal rod passage <NUM>. A second set screw (not shown in <FIG>, but as shown in <FIG>) can be screwed into the second internally threaded set screw opening <NUM> to engage and tighten on the second spinal rod inside the second spinal rod passage <NUM>. Once inserted and secured by the set screw, it can be understood that the end of the second spinal rod can be secured in a fixed position with reference to the imaginary first reference plane <NUM> and the imaginary second reference plane <NUM>. In an embodiment, once inserted and secured, the end of the second spinal rod can be secured in a fixed position parallel to one or both of the imaginary first reference plane <NUM> and the imaginary second reference plane <NUM>. In an embodiment, the second spinal rod passage axis <NUM> and the second set screw axis <NUM> are co-planar.

As can be understood with reference to the description herein, including with reference to <FIG>, one of the first spinal rod passage <NUM> and the second spinal rod passage <NUM> can have a size and shape to facilitate variable spinal rod axis positions. For example, as shown in <FIG>, in an embodiment of the polyaxial connector <NUM>, the first spinal rod passage <NUM> can be generally cylindrical in shape, while the second spinal rod passage <NUM> can have a shape S that in cross section at imaginary second reference plane <NUM> generally approximates an hourglass shape <NUM>, as depicted in a dashed outline in <FIG>. The term "hourglass shape" is used to describe a cross sectional shape that is defined by the internal sidewalls <NUM> of the second spinal rod passage that converge internally from the opening on each side of the polyaxial connector <NUM> external surface <NUM> toward one another to a vertex <NUM> on each side at the narrowest throat portion <NUM> through which a spinal fixation rod can pass to be connected by the polyaxial connector <NUM>. In an embodiment, as discussed below, both of the first and second spinal rod passages can have a shape S that in cross section at imaginary second reference plane <NUM> generally approximates an hourglass shape <NUM>. The shape S can be any shape that permits variable spinal rod axis positions. Thus, the shape S can be generally rectangular, with dimensions permitting variable spinal rod axis positions. However, it is believed that greater securing accuracy can be achieved when the shape S is defined by internal sidewalls <NUM> that together approximate an hourglass shape because the internal sidewalls <NUM> converge to a vertex <NUM> at a narrowest throat portion <NUM>, with the parallel opposing sidewalls <NUM> being spaced to a dimension SRW that is at least equal to the width of a spinal rod. The width dimension SRW can range from about <NUM> to about <NUM>. Likewise, the diameter of any cylindrical shaped spinal rod passages, such as the first spinal rod passage <NUM> in <FIG>, can have a diameter of between about <NUM> to about <NUM>.

The various orientations of second spinal rod passage axes <NUM> shown, i.e., 124A-124C are simply three examples of what is virtually an infinite range of orientation, that can sweep an arc of, in an embodiment, up to and including <NUM> degrees, and as disclosed in more detail with reference to <FIG>, below. In the embodiment depicted in <FIG>, for example, once inserted in the second spinal rod passage <NUM>, the connected portion of the second spinal rod can be secured at the first variable rod axis 124A such that its axis is generally parallel to the imaginary second reference plane <NUM> but at an angle to the imaginary first reference plane <NUM>. In this manner a non-parallel alignment of a first spinal rod end and a second spinal rod end can be accommodated and joined in a plane.

To aid in the secure joining of non-parallel spinal rod ends, one of the spinal rod openings, for example the second spinal rod passage <NUM> shown in <FIG>, can have disposed therein a spinal rod cradle rest <NUM>, shown in more detail in <FIG>. Referring to <FIG>, an example spinal rod cradle rest <NUM> can be a generally circular-shaped member having straight sidewalls (<FIG>) or inwardly tapering sidewalls (<FIG>), the sidewalls joining a contoured upper surface <NUM>, which can be a spinal rod-contacting surface, to a cradle base <NUM> which can be a relatively flat surface that rests in moveable contact with the first passage surface <NUM> of the second spinal rod passage <NUM>. The spinal rod cradle rest <NUM> can have a central cradle axis <NUM> oriented perpendicular to the cradle base <NUM> and which, when used in a the polyaxial connector <NUM>, can be co-axial with the second set screw axis <NUM>. The contoured upper surface <NUM> can have a radius of curvature R, the radius of curvature R being from a cradle rest axis <NUM>, and which can approximate to the radius of a spinal fixation rod, which can be about <NUM> to about <NUM>.

Thus, the spinal rod cradle rest <NUM> can be disposed in a spinal rod passage, such as the second spinal rod passage <NUM>, as rotatable member with the central cradle axis <NUM> generally co-axial with the second set screw axis <NUM>. As depicted in <FIG>, the spinal rod cradle rest <NUM> can be fitted in a notch <NUM> in the vertex <NUM> defined where each internal sidewall <NUM> meets at its narrowest throat portion <NUM>, which is the narrowest portion through which a spinal fixation rod can pass to be connected by the polyaxial connector <NUM>. A spinal fixation rod to be fixed in the second spinal rod passage <NUM> can be inserted with its axis aligned with the cradle rest axis <NUM>, and the spinal rod cradle rest <NUM> can then be rotated about the central cradle axis <NUM> to align the spinal fixation rod axis with any of the variable axes, such as second axis 124B or 124C. A second spinal fixation rod can be secured by rotating the second set screw to tighten on the internal threads of the second internally threaded set screw opening <NUM> which then engages and tightens on the second spinal fixation rod disposed between the second set screw and the contoured upper surface <NUM> of the spinal rod cradle rest <NUM>. Thus, the second spinal fixation rod can be secured at a selected angle relative to the first spinal fixation rod, with the second spinal fixation rod being secured by the second set screw urging the second spinal fixation rod against the curved shape of the spinal rod cradle rest <NUM>, with the cradle rest axis <NUM> corresponding to the direction of a selected variable rod axis.

Referring now to <FIG>, there is shown another embodiment of a polyaxial connector in which both of the spinal rod openings can facilitate variable axis connection of spinal fixation rods. A polyaxial connector <NUM> as shown can be useful for connecting the ends of two spinal fixation rods that are not parallel in the same plane. The polyaxial connector <NUM> has a connector body <NUM>, which, as above, can be understood with reference to two imaginary intersecting, orthogonal planes: an imaginary first reference plane <NUM> and an imaginary second reference plane <NUM>. The imaginary first reference plane <NUM> divides the polyaxial connector body into two portions, a first body portion <NUM> and a second body portion <NUM>.

The polyaxial connector <NUM> has an external surface <NUM>, the external surface defining a plurality of openings that pass through at least a portion of the polyaxial connector <NUM>. The external surface <NUM> on the first body portion <NUM> defines openings to a first spinal rod passage <NUM> defining a first spinal rod passage axis <NUM>. The first spinal rod passage <NUM> passes completely through the connector body <NUM> and serves as a passage for connecting a first spinal rod (not shown in <FIG>, but as shown in <FIG>), the first spinal rod having a first spinal rod axis that can be, when connected, co-axial with the first spinal rod passage axis <NUM>. The first spinal rod passage axis <NUM> can be one of a plurality of axes in virtually an infinite range of orientation that, in an embodiment, can sweep an arc <NUM> of, in an embodiment, up to and including <NUM> degrees. The external surface <NUM> on the first body portion <NUM> defines a first internally threaded set screw opening <NUM> defining a first set screw axis <NUM>. A first set screw (not shown in <FIG>, but as shown in <FIG>) can be screwed into the first internally threaded set screw opening <NUM> to engage and tighten on the first spinal rod inside the first spinal rod passage <NUM>. Once inserted and secured, it can be understood that the end of the first spinal rod can be secured in a fixed position with reference to the imaginary first reference plane <NUM> and the imaginary second reference plane <NUM>. In an embodiment, once inserted and secured, the end of the first spinal rod can be secured in a fixed position parallel to one or both of the imaginary first reference plane <NUM> and the imaginary second reference plane <NUM>. In an embodiment, the first spinal rod passage axis <NUM> and the first set screw axis <NUM> are co-planar.

Referring again to <FIG>, the external surface <NUM> on the second body portion <NUM> defines openings to a second spinal rod passage <NUM> defining a second spinal rod passage axis <NUM>. As with the first spinal rod passage axis <NUM> and the second spinal rod passage axis <NUM> of <FIG>, the second spinal rod passage axis <NUM> in <FIG> can be one of a plurality of axes in virtually an infinite range of orientation that can sweep an arc <NUM> of, in an embodiment, up to and including <NUM> degrees. The second spinal rod passage <NUM> passes completely through the connector body <NUM> and serves as a passage for connecting a second spinal rod (not shown in <FIG>, but as shown in <FIG>), the second spinal rod having a second spinal rod axis that can be, when connected, co-axial with the second spinal rod passage axis <NUM>. The external surface <NUM> on the second body portion <NUM> defines a second internally threaded set screw opening <NUM> defining a second set screw axis <NUM>. The second spinal rod can be inserted in the second spinal rod passage <NUM>. A second set screw (not shown in <FIG>, but as shown in <FIG>) can be screwed into the second internally threaded set screw opening <NUM> to engage and tighten on the second spinal rod inside the second spinal rod passage <NUM>. Once inserted and secured by the set screw, it can be understood that the end of the second spinal rod can be secured in a fixed position with reference to the imaginary first reference plane <NUM> and the imaginary second reference plane <NUM>. In an embodiment, once inserted and secured, the end of the second spinal rod can be secured in a fixed position parallel to one or both of the imaginary first reference plane <NUM> and the imaginary second reference plane <NUM>. In an embodiment, the second spinal rod passage axis <NUM> and the second set screw axis <NUM> are co-planar.

In an embodiment of a polyaxial connector, such as the polyaxial connector <NUM> shown in <FIG>, both the first spinal rod passage <NUM> and the second spinal rod passage <NUM> can include therein in each a spinal rod cradle rest. Thus, first spinal rod passage <NUM> can have associated there with a first spinal rod cradle rest 136A, and the second spinal rod passage <NUM> can have a second spinal rod cradle rest 136B. The first spinal rod cradle rest 136A, and the second spinal rod cradle rest 136B can each have the structure, function and benefits as discussed above with the spinal rod cradle rest <NUM>. In particular, the first spinal rod cradle rest 136A can have a first central cradle axis 138A oriented perpendicular to the first cradle base 140A (not shown in <FIG>, but corresponding to the cradle base <NUM> described above) and which, when used in the polyaxial connector <NUM>, can be co-axial with the first set screw axis <NUM>. Likewise, the second spinal rod cradle rest 136B can have a second central cradle axis 138B oriented perpendicular to the second cradle base 140B (not shown in <FIG>, but corresponding to the cradle base <NUM> described above) and which, when used in the polyaxial connector <NUM>, can be co-axial with the second set screw axis <NUM>.

As can be understood from the description herein, the polyaxial connector <NUM> shown in <FIG> permits two spinal fixation rods to be joined in a non-parallel, non-planar configuration. Both the first spinal rod passage <NUM> and the second spinal rod passage <NUM> can have hourglass-shaped cross sections, as described above. The first spinal rod passage <NUM> can have sides that define a generally hourglass shape across a plane parallel with the imaginary first reference plane <NUM>. The second spinal rod passage <NUM> can have sides that define a generally hourglass shape across a plane parallel with the imaginary second reference plane <NUM>. Thus, a spinal fixation rod secured in the first spinal rod passage, as described above, can be secured in a range of axis orientations, each corresponding to the first spinal rod passage axis <NUM> and each generally parallel to the imaginary first reference plane <NUM>. Likewise, a spinal fixation rod secured in the second spinal rod passage, as described above, can be secured in a range of axis orientations, each corresponding to the second spinal rod passage axis <NUM> and each generally parallel to the imaginary second reference plane <NUM>. In this illustrated embodiment, when spinal fixation rods are secured in the polyaxial connector <NUM>, they can be oriented generally as depicted with respect to the spinal rods shown in <FIG>, described in more detail below.

In can be observed in the embodiments of polyaxial connectors depicted in <FIG> that the various features described herein can be utilized and oriented in beneficial variations with the structure, function and benefits best described with respect to the imaginary reference frames. Thus, the polyaxial connector <NUM> shown in <FIG>, illustrates that in certain embodiments, a first spinal rod passage can be generally cylindrical and a second spinal rod passage can have a generally hourglass shaped cross section. Also, a first set screw axis and second set screw axis can be parallel and co-planar. Additionally, a first set screw axis and a second set screw axis can be parallel to an imaginary first plane. Reference to the polyaxial connector <NUM> in <FIG>, illustrates that in certain embodiments, both a first spinal rod passage and a second spinal rod passage can each have a generally hourglass shaped cross section. Also, a first set screw axis and second set screw axis can be perpendicular and co-planar. Additionally, a first set screw axis can be perpendicular to one of the imaginary first reference plane or the second reference plane, and a second set screw axis can be parallel to one of the imaginary first reference plane or the second reference plane. While not shown, it can be understood that further configurations can be achieved. For example, similar to the embodiment of a polyaxial connector <NUM> in <FIG>, the second spinal rod passage <NUM> can have a second internally threaded set screw opening <NUM> defining a second set screw axis <NUM> that is co-axial with the first set screw axis <NUM>.

In general, it can be observed that a polyaxial connector can include a spinal rod cradle rest in none, one, or both, of the spinal rod passages. For example, in the example depicted in <FIG>, one of the spinal rod passages utilizes a spinal rod cradle rest. In the example embodiment depicted in <FIG>, both of the spinal rod passages utilize a spinal rod cradle rest. Referring now to <FIG>, there is shown a polyaxial connector in which no spinal rod cradle rests are utilized. The polyaxial connector depicted in <FIG> can be generally as described as the polyaxial connector <NUM> above, but without a spinal rod cradle rest in either of the first spinal rod passages. Referring to <FIG>, there is shown a polyaxial connector <NUM> that includes a connector body <NUM>, which, as above, can be understood with reference to two imaginary intersecting, orthogonal planes: an imaginary first reference plane <NUM> and an imaginary second reference plane <NUM>. The imaginary first reference plane <NUM> divides the connector body <NUM> into two portions, a first body portion <NUM> and a second body portion <NUM>.

The polyaxial connector <NUM> has an external surface <NUM>, the external surface defining a plurality of openings that pass through at least a portion of the polyaxial connector <NUM>. The external surface <NUM> on the first body portion <NUM> defines openings to a first spinal rod passage <NUM> defining a first spinal rod passage axis <NUM>. As discussed above, the first spinal rod passage axis <NUM> can be one of a plurality of axes in virtually an infinite range of orientation that can sweep an arc <NUM> of, in an embodiment, up to and including <NUM> degrees. The first spinal rod passage <NUM> passes completely through the connector body <NUM> and serves as a passage for connecting a first spinal rod <NUM>, the first spinal rod <NUM> having a first spinal rod axis <NUM> that can be, when connected, co-axial with the first spinal rod passage axis <NUM>. The external surface <NUM> on the first body portion <NUM> defines a first internally threaded set screw opening <NUM> defining a first set screw axis <NUM>. A first set screw (not shown in <FIG>, but as shown in <FIG>) can be screwed into the first internally threaded set screw opening <NUM> to engage and tighten on the first spinal rod <NUM> inside the first spinal rod passage <NUM>. Once inserted and secured, it can be understood that the end of the first spinal rod <NUM> can be secured in a fixed position with reference to the imaginary first reference plane <NUM> and the imaginary second reference plane <NUM>. In an embodiment, once inserted and secured, the end of the first spinal rod <NUM> can be secured in a fixed position parallel to one or both of the imaginary first reference plane <NUM> and the imaginary second reference plane <NUM>. In an embodiment, the first spinal rod passage axis <NUM> and the first set screw axis <NUM> are co-planar.

Referring again to <FIG>, the external surface <NUM> on the second body portion <NUM> defines openings to a second spinal rod passage <NUM> defining a second spinal rod passage axis <NUM>. The second spinal rod passage <NUM> passes completely through the connector body <NUM> and serves as a passage for connecting a second spinal rod <NUM>, the second spinal rod having a second spinal rod axis <NUM> that can be, when connected, co-axial with the second spinal rod passage axis <NUM>. The external surface <NUM> on the second body portion <NUM> defines a second internally threaded set screw opening <NUM> defining a second set screw axis <NUM>. The second spinal rod <NUM> can be inserted in the second spinal rod passage <NUM>. A second set screw (not shown in <FIG>, but as shown in <FIG>) can be screwed into the second internally threaded set screw opening <NUM> to engage and tighten on the second spinal rod <NUM> inside the second spinal rod passage <NUM>. Once inserted and secured by the set screw, it can be understood that the end of the second spinal rod <NUM> can be secured in a fixed position with reference to the imaginary first reference plane <NUM> and the imaginary second reference plane <NUM>. In an embodiment, once inserted and secured, the end of the second spinal rod <NUM> can be secured in a fixed position such that the second spinal rod axis <NUM> is parallel to one or both of the imaginary first reference plane <NUM> and the imaginary second reference plane <NUM>. In an embodiment, the second spinal rod passage axis <NUM> and the second set screw axis <NUM> are co-planar.

Referring now to <FIG>, certain benefits and advantages of the hourglass shaped cross section of a spinal rod passage are illustrated. As discussed above, the generally hourglass cross sectional shape of a spinal rod passage, such as second spinal rod passage <NUM> in <FIG> and <FIG>, permits the securement of a spinal rod, such as the second spinal rod <NUM> in a range of axial orientations with respect to an imaginary reference plane, such as imaginary first reference plane <NUM>. By way of example, second spinal rod <NUM> can be secured in the second spinal rod passage <NUM> by the second set screw threaded into the second internally threaded set screw opening <NUM>, which can tighten on the second spinal rod as it is pressed against the opposite side, i.e., surface <NUM> in <FIG>. The second spinal rod <NUM> can be secured in a range of axial orientations within an arc <NUM>, which in example embodiments can be up to and include <NUM> degrees, and which corresponds, for example, to the range of the second spinal rod passage axis <NUM>, shown in <FIG>. As discussed with reference to <FIG>, the parallel opposing internal sides <NUM> of the second spinal rod passage <NUM> can be spaced to conform at least to the width of a spinal rod SRW to provide for additional securement surfaces. Thus, a first spinal fixation rod can be secured in one spinal rod passage at an angle with respect to an imaginary reference plane, and, in certain embodiments, at an angle with respect to a second spinal fixation rod. In an embodiment, a first spinal fixation rod can be secured in a non-planar, non-parallel orientation with respect to a second spinal fixation rod.

Referring now to <FIG> and <FIG>, there are shown embodiments of example polyaxial connectors in which two spinal fixation rods can be connected in a planar, non-parallel configuration. The example embodiments build on the structures and design principles disclosed hereinabove, and include alternative structures and features that provide for added flexibility in spinal rod fixation. Without repeating all the common features evident on and described above, the following features are described. The connector <NUM> of <FIG> exhibits a first spinal rod passage <NUM> having sidewalls <NUM> that, as described above, converge internally to define a shape that in cross section at imaginary second reference plane <NUM> generally approximates an hourglass shape. Thus, a spinal rod secured in the first spinal rod passage <NUM> can be positioned with its axis generally parallel to and/or co-axial to the first spinal rod passage axis <NUM>, which can be one of any within the first spinal rod passage axes range 416R, each of which are substantially parallel to the imaginary second reference plane <NUM>. The first spinal rod passage axes range 416R represents what is virtually an infinite range of axis orientation that can sweep an arc of, in an embodiment, up to and including <NUM> degrees. The connector <NUM> also exhibits a first internally threaded set screw opening <NUM> defining a first set screw axis <NUM>. The first spinal rod passage <NUM> can have a first passage surface <NUM> which can be a generally flat interior surface disposed opposite the first internally threaded set screw opening <NUM>. In use, a spinal fixation rod inserted into the first spinal rod passage <NUM> can be oriented parallel to a first spinal rod passage axis <NUM>, which can be one of a range of first spinal rod passage axes 416A, the range being up to and including <NUM> degrees, and can be secured by a set screw threaded into the first internally threaded set screw opening <NUM> toward the first passage surface <NUM>, thereby securing the spinal fixation rod between the tightened set screw and the first passage surface.

Likewise, the connector <NUM> exhibits a second spinal rod passage <NUM> having sidewalls <NUM> that, as described above, converge internally to define a shape that in cross section at imaginary second reference plane <NUM> generally approximates an hourglass shape. Thus, a spinal rod secured in the second spinal rod passage <NUM> can be positioned with its axis generally parallel to and/or co-axial to the second spinal rod passage axis <NUM>, which can one of any within the second spinal rod passage axis range 424R, each of which are substantially parallel to the imaginary second reference plane <NUM>. The second spinal rod passage axes range 424R represents what is virtually an infinite range of axis orientation that can sweep an arc of, in an embodiment, up to and including <NUM> degrees. The connector <NUM> also exhibits a second internally threaded set screw opening <NUM> defining a second set screw axis <NUM>. The second spinal rod passage <NUM> can have a second passage surface <NUM> which can be a generally flat interior surface disposed opposite the second internally threaded set screw opening <NUM>. In use, a spinal fixation rod inserted into the second spinal rod passage <NUM> can be oriented parallel to a second spinal rod passage axis <NUM>, which can be one of any within the second spinal rod passage axis range 424R of up to and including <NUM> degrees, and can be secured by a set screw threaded into the second internally threaded set screw opening <NUM> toward the second passage surface <NUM>, thereby securing the spinal fixation rod between the tightened set screw and the second passage surface.

The connector <NUM> of <FIG> exhibits similar features as described above with respect to connector <NUM> shown in <FIG>, but with the difference being that both of the spinal rod passages include a first spinal rod cradle rest 136A, as described above and with reference to <FIG>, to provide for enhanced securement of a spinal fixation rod, as discussed above. The connector <NUM> can have a first spinal rod passage <NUM> having sidewalls <NUM> that, as described above, converge internally to define a shape that in cross section at imaginary second reference plane <NUM> generally approximates an hourglass shape. Thus, a spinal rod secured in the first spinal rod passage <NUM> can be positioned with its axis generally parallel to and/or co-axial to the first spinal rod passage axis <NUM>, which can be one of any within the first spinal rod passage range 516R, each of which can be substantially parallel to the imaginary second reference plane <NUM>. The first spinal rod passage axes range 516R represents what is virtually an infinite range of axis orientation that can sweep an arc of, in an embodiment, up to and including <NUM> degrees. The connector <NUM> also exhibits a first internally threaded set screw opening <NUM> defining a first set screw axis <NUM>. The first spinal rod passage <NUM> can have a first passage surface <NUM> which can be a generally flat interior surface disposed opposite the first internally threaded set screw opening <NUM>. The first spinal rod cradle rest 136A can be disposed in the first spinal rod passage <NUM> such that the cradle base <NUM> rests in moveable contact with the first passage surface <NUM> of the first spinal rod passage <NUM>. The first spinal rod cradle rest 136A can be at least partially secured in the first spinal rod passage <NUM> by a notch in the sidewall vertex <NUM>, as described above. The first spinal rod cradle rest 136A can have a central cradle axis <NUM> oriented perpendicular to the cradle base <NUM> and which, when used in a connector <NUM>, can be co-axial with the first set screw axis <NUM> such that a spinal fixation rod to be fixed in the first spinal rod passage <NUM> can be inserted with its axis aligned with the cradle rest axis <NUM>, and the first spinal rod cradle rest 136A can then be rotated about the central cradle axis <NUM> to align the spinal fixation rod axis which can be oriented parallel to a first spinal rod passage axis <NUM>, and which can one of any within the first spinal rod passage range 516R, each of which are substantially parallel to the imaginary second reference plane <NUM>. The spinal fixation rod can be secured by a set screw threaded into the first internally threaded set screw opening <NUM> toward the first passage surface <NUM>, thereby securing the spinal fixation rod between the tightened set screw and the contoured upper surface <NUM> of the first spinal rod cradle rest 136A.

Likewise, the connector <NUM> can have a second spinal rod passage <NUM> having sidewalls <NUM> that, as described above, converge internally to define a shape that in cross section at imaginary second reference plane <NUM> generally approximates an hourglass shape. Thus, a spinal rod secured in the second spinal rod passage <NUM> can be positioned with its axis generally parallel to and/or co-axial to the second spinal rod passage axis <NUM>, which can be one of any within the second spinal rod passage range 524R, each of which can be substantially parallel to the imaginary second reference plane <NUM>. The second spinal rod passage axes range 424R represents what is virtually an infinite range of axis orientation that can sweep an arc of, in an embodiment, up to and including <NUM> degrees. The connector <NUM> also exhibits a second internally threaded set screw opening <NUM> defining a second set screw axis <NUM>. The second spinal rod passage <NUM> can have a second passage surface <NUM> which can be a generally flat interior surface disposed opposite the second internally threaded set screw opening <NUM>. A second spinal rod cradle rest 136B can be disposed in the second spinal rod passage <NUM> such that the cradle base <NUM> rests in moveable contact with the second passage surface <NUM> of the second spinal rod passage <NUM>. The second spinal rod cradle rest 136B can be at least partially secured in the second spinal rod passage <NUM> by a notch in the sidewall vertex <NUM>, as described above. The second spinal rod cradle rest 136B can have a central cradle axis <NUM> oriented perpendicular to the cradle base <NUM> and which, when used in a connector <NUM>, can be co-axial with the second set screw axis <NUM> such that a spinal fixation rod to be fixed in the second spinal rod passage <NUM> can be inserted with its axis aligned with the cradle rest axis <NUM>, and the second spinal rod cradle rest 136B can then be rotated about the central cradle axis <NUM> to align the spinal fixation rod axis which can be oriented parallel to a second spinal rod passage axis <NUM>, and which can one of any within the second spinal rod passage range 524R, each of which are substantially parallel to the imaginary second reference plane <NUM>. The spinal fixation rod can be secured by a set screw threaded into the second internally threaded set screw opening <NUM> toward the second passage surface <NUM>, thereby securing the spinal fixation rod between the tightened set screw and the contoured upper surface <NUM> of the second spinal rod cradle rest 136B.

<FIG> depict a spinal rod cradle rest <NUM>, which can be used to enhance the securement of a spinal fixation rod in a polyaxial connector, as discussed above.

<FIG> depicts another example of a spinal rod cradle rest. The spinal rod cradle rest <NUM> can be a generally circular-shaped member having a cradle base <NUM> which can be a relatively flat surface that rests in moveable contact with the first passage surface of a spinal rod passage, as discussed above. The spinal rod cradle rest <NUM> can have a central cradle axis <NUM> oriented perpendicular to the cradle base <NUM> and which, when used in a polyaxial connector can be co-axial with the set screw axis. The spinal rod cradle rest <NUM> can have a contoured upper surface <NUM> having a having a radius of curvature as discussed above with respect to the spinal rod cradle rest <NUM>. The spinal rod cradle rest <NUM> can have an engagement member, which can be a groove <NUM> and/or a circumferentially extending rib <NUM>, either or both of which can be disposed in a cooperating relationship with similar features on the connector in the spinal rod passage in which they are disposed. Groove <NUM> can be a portion of the spinal rod cradle rest <NUM> that is indented relative to an outer side wall of the spinal rod cradle rest <NUM>, such as side wall <NUM>. The circumferentially extending rib <NUM> can be a member that extends outwardly from portions of the spinal rod cradle rest <NUM>, and which can also include further extensions, such as one or more tabs <NUM>. As can be understood, the groove <NUM> and/or a circumferentially extending rib <NUM> feature(s) can be utilized to cooperate with mating features on a polyaxial connector to aid in securing the spinal rod cradle axis in the connector prior to use in securing a spinal fixation rod in the connector.

Referring to the above-described examples, the connectors can be characterized as having two spinal rod passages in which the respective set screw axes are parallel and planar (e.g., <FIG> and <FIG>) or perpendicular and planar (e.g., <FIG>). Further, they can be characterized as including a spinal rod cradle rest in one spinal rod passage (e.g., <FIG>) or two spinal rod passages (e.g., <FIG> and <FIG>), or neither spinal rod passage (e.g., <FIG>).

Referring to FIGS. <NUM>-<NUM>, there are shown example embodiments of polyaxial connectors that include and build on the structures and design principles disclosed hereinabove, and which include alternative structures and features that provide for added flexibility in spinal rod fixation. That is, the example connectors depicted and described in FIGS. <NUM>-<NUM> can include any and all of the features described above, but which features, in the interest of conciseness, are not fully described again. Thus, for example, the polyaxial connector <NUM> described below is not shown utilizing a spinal rod cradle rest in either spinal rod passage, yet it is understood that the polyaxial connector <NUM> can optionally include a spinal rod cradle rest in either or both spinal rod passages, based on the descriptions herein.

Polyaxial connector <NUM> shown in <FIG> has connector body <NUM> including a first spinal rod passage <NUM> defining a first spinal rod passage axis <NUM> and a first internally threaded set screw opening <NUM> defining a first set screw axis <NUM>. The polyaxial connector <NUM> can have a second spinal rod passage <NUM> defining a second spinal rod passage axis <NUM> and a second internally threaded set screw opening <NUM> defining a second set screw axis <NUM>. The polyaxial connector <NUM> can be described as a hybrid of the previously described connectors, in that the respective set screw axes are non-perpendicular, non-parallel and planar. The respective set screw axes can sweep an angle <NUM> of between <NUM> degree and <NUM> degrees to provide enhanced flexibility with respect to the mutual orientation of connected spinal fixation rods.

Polyaxial connector <NUM> shown in <FIG> has connector body <NUM> including a first spinal rod passage <NUM> defining a first spinal rod passage axis <NUM>. The polyaxial connector <NUM> can have a second spinal rod passage <NUM> defining a second spinal rod passage axis <NUM> and a second internally threaded set screw opening <NUM> defining a second set screw axis <NUM>. The polyaxial connector <NUM> can be described as a hybrid of the previously described connectors, in that the connector body <NUM> includes a first spinal rod passage <NUM> that can be a cylindrical passage, a spinal rod cradle rest <NUM> in one of the spinal rod passages, namely the second spinal rod passage <NUM>, and the respective set screw axes are non-perpendicular, non-parallel and planar. The respective set screw axes can sweep an angle <NUM> of between <NUM> degree and <NUM> degrees to provide enhanced flexibility with respect to the mutual orientation of connected spinal fixation rods.

Polyaxial connector <NUM> shown in <FIG> has connector body <NUM> that can be intersected by a first imaginary reference plane <NUM> into a first body portion <NUM> and a second body portion <NUM>, which can be substantially mirror images of one another. The first body portion <NUM> includes a first spinal rod passage <NUM> defining a first spinal rod passage axis <NUM> and a first internally threaded set screw opening <NUM> defining a first set screw axis <NUM>. The first spinal rod passage axis <NUM> can be one of a plurality of axes in virtually an infinite range of orientation that, in an embodiment, can sweep an arc <NUM> of, in an embodiment, up to and including <NUM> degrees. The second body portion <NUM> can have a second spinal rod passage <NUM> defining a second spinal rod passage axis <NUM> and a second internally threaded set screw opening <NUM> defining a second set screw axis <NUM>. The second spinal rod passage axis <NUM> can be one of a plurality of axes in virtually an infinite range of orientation that, in an embodiment, can sweep an arc <NUM> of, in an embodiment, up to and including <NUM> degrees. The respective set screw axes are non-perpendicular, non-parallel and planar. The respective set screw axes can sweep an angle <NUM> of between <NUM> degrees and <NUM> degrees, or between <NUM> degree and <NUM> degrees, to provide enhanced flexibility with respect to the mutual orientation of connected spinal fixation rods.

Referring to <FIG> and <FIG>, there are shown example embodiments of polyaxial connectors that include and build on the structures and design principles disclosed hereinabove, and which include alternative structures and features that provide for added flexibility in spinal rod fixation. That is, the example connectors depicted and described in <FIG> and <FIG> can include any or all of the features described above, but which features, in the interest of conciseness, are not fully described again. The polyaxial connector <NUM> shown in <FIG> has a connector body <NUM> and a first body portion <NUM> including a first spinal rod passage <NUM> defining a first spinal rod passage axis <NUM>. The polyaxial connector <NUM> can have a second spinal rod passage <NUM> defining a second spinal rod passage axis <NUM> and a second internally threaded set screw opening <NUM> defining a second set screw axis <NUM>. The second spinal rod passage <NUM> can have a spinal rod cradle rest <NUM> incorporated therein. As can be understood, the polyaxial connector <NUM> is similar in most respects to the polyaxial connector <NUM> described with respect to <FIG>. However, rather than being a cylindrical passage through the connector, the first spinal rod passage <NUM> of the polyaxial connector <NUM> can be substantially U-shaped and open at the first internally threaded set screw opening <NUM>. With this design feature a spinal fixation rod can be introduced into the first spinal rod passage <NUM> from the top, through the open portion of the first internally threaded set screw opening <NUM>, rather than being inserted, i.e., threaded, through a cylindrical shaped opening.

The connector <NUM> shown in <FIG> has a connector body <NUM> and a first body portion <NUM> including a first spinal rod passage <NUM> defining a first spinal rod passage axis <NUM>. The connector <NUM> can have a second spinal rod passage <NUM> defining a second spinal rod passage axis <NUM> and a second internally threaded set screw opening <NUM> defining a second set screw axis <NUM>. As can be understood, the connector <NUM> is similar in most respects to the polyaxial connector <NUM> described with respect to <FIG>. However, rather than being a cylindrical passage through the connector, the first spinal rod passage <NUM> of the connector <NUM> can be substantially U-shaped and open at the first internally threaded set screw opening <NUM>. With this design feature a spinal fixation rod can be introduced into the first spinal rod passage <NUM> from the top, through the open portion of the first internally threaded set screw opening <NUM>, rather than being inserted, i.e., threaded, through a cylindrical shaped opening.

The various features of either the first portions or second portions of the connector bodies described above can also be incorporated on cylindrical extension to provide the benefits of a polyaxial connector to a lateral connector, which can be an elevated inline lateral connector, an elevated lateral connector, and the like. The connector <NUM> shown in <FIG> can have a polyaxial connector portion <NUM> that can include any of the above-described connector structures and features. Such structures and features, as described above, permit a spinal fixation rod <NUM> to be secured by a set screw through a set screw threaded opening <NUM> such that the spinal fixation rod central axis <NUM> can be oriented at a range of orientations from a first orientation 1054A to a second orientation 1054B, through an arc of axis variation <NUM>. The arc of axis variation <NUM> can be up to and include about <NUM> degrees or more.

The polyaxial connector portion <NUM> can have extended from a portion thereof a lateral extension <NUM>, which can be a rod-like extension. The lateral extension can be substantially straight, as shown in <FIG>, or it can be curved, including L-shaped. The lateral extension <NUM> permits the polyaxial connector portion <NUM> to be connected to another spinal rod fixation component, such as the tulip head of a pedicle screw, as is known in the art.

Claim 1:
A polyaxial rod connector (<NUM>), the polyaxial rod connector (<NUM>) comprising a connector body (<NUM>), the connector body having an external surface (<NUM>), the connector body being intersected by an imaginary first reference plane (<NUM>) and an imaginary second reference plane (<NUM>) perpendicular to the imaginary first reference plane (<NUM>),
a. a first body portion (<NUM>) being on a first side of the imaginary first reference plane (<NUM>), the first body portion defining openings to a first spinal rod passage (<NUM>) defining a first spinal rod passage axis (<NUM>) and a first internally threaded set screw opening (<NUM>) defining a first set screw axis (<NUM>) perpendicular to the first spinal rod passage axis (<NUM>);
b. a second body portion (<NUM>) adjoined to the first body portion on a second side of the imaginary first reference plane (<NUM>), the second body portion defining openings to a second spinal rod passage (<NUM>) defining a plurality of second spinal rod passage axes (<NUM>), and a second internally threaded set screw opening (<NUM>) defining a second set screw axis (<NUM>) perpendicular to each of the plurality of second spinal rod passage axes (<NUM>);
c. wherein the first spinal rod passage axis (<NUM>) is non-parallel with at least one of the plurality of second spinal rod passage axes (<NUM>) in the imaginary second reference plane (<NUM>); and
d. characterized in that one of the first spinal rod passage (<NUM>) and the second spinal rod passage (<NUM>) comprises a generally hourglass shaped cross section parallel to the imaginary second reference plane (<NUM>).