Patent ID: 12232777

While the invention is amenable to various modifications and alternative forms, specifics thereof have been shown by way of example in the drawings and will be described in detail. It should be understood, however, that the intention is not to limit aspects of the invention to the particular embodiments described. On the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

DETAILED DESCRIPTION

For the following defined terms, these definitions shall be applied, unless a different definition is given in the claims or elsewhere in this specification.

All numeric values are herein assumed to be modified by the term “about”, whether or not explicitly indicated. The term “about” generally refers to a range of numbers that one of skill in the art would consider equivalent to the recited value (i.e., having the same function or result). In many instances, the term “about” may be indicative as including numbers that are rounded to the nearest significant figure.

The recitation of numerical ranges by endpoints includes all numbers within that range (e.g., 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, and 5).

Although some suitable dimensions ranges and/or values pertaining to various components, features and/or specifications are disclosed, one of skill in the art, incited by the present disclosure, would understand desired dimensions, ranges and/or values may deviate from those expressly disclosed.

As used in this specification and the appended claims, the singular forms “a”, “an”, and “the” include plural referents unless the content clearly dictates otherwise. As used in this specification and the appended claims, the term “or” is generally employed in its sense including “and/or” unless the content clearly dictates otherwise.

The following detailed description should be read with reference to the drawings in which similar elements in different drawings are numbered the same. The detailed description and the drawings, which are not necessarily to scale, depict illustrative embodiments and are not intended to limit the scope of the invention. The illustrative embodiments depicted are intended only as exemplary. Selected features of any illustrative embodiment may be incorporated into an additional embodiment unless clearly stated to the contrary.

Referring now toFIG.1, there is shown a spinal fixation system10for stabilizing a portion of a spinal column, such as one or more spinal segments of a spinal column. As used herein, a spinal segment is intended to refer to two or more vertebrae, the intervertebral disc(s) between the vertebrae and other anatomical elements between the vertebrae. For example, a spinal segment can include first and second adjacent vertebrae and the intervertebral disc located between the first and second vertebrae. The spinal stabilization system10can provide dynamic stabilization to a spinal segment, preserving and/or allowing for a range of motion of the spinal segment.

In some embodiments, the spinal stabilization system10can be used to treat discogenic low back pain, degenerative spinal stenosis, disc herniations, facet syndrome, posterior element instability, adjacent level syndrome associated with spinal fusion, and/or other maladies associated with the spinal column.

The spinal stabilization system10can include one or more or a plurality of vertebral anchors, depicted as pedicle screws12. However, in some embodiments the vertebral anchors can be vertebral hooks (e.g., laminar hooks) or other types of fastening members for attachment to a bony structure such as a vertebra of the spinal column. Each of the pedicle screws12can be configured to be secured to a vertebra of a spinal column. For instance, the first pedicle screw12acan be secured to a first vertebra and the second pedicle screw12bcan be secured to a second vertebra. Additional pedicle screws12can be present in instances in which the spinal stabilization system10spans three or more vertebra of the spinal column.

The pedicle screw12can include a housing14and a shaft16, which can include threads18, extending from the housing14. The housing14can include a channel, such as a U-shaped channel extending from one side of the housing14to an opposite second side of the housing14. The channel15(seeFIG.2) can be defined between opposing legs of the housing14. The shaft16can be configured to be installed into a bony region of a vertebra of the spinal column. For example, the shaft16can be installed into a pedicle of a vertebra, or other region of a vertebra. The shaft16can extend along a longitudinal axis. The pedicle screw12depicted in the Figures is a poly-axial pedicle screw which allows the housing14to be pivotable relative to the shaft16to a plurality of angular positions relative to the longitudinal axis. The pedicle screw12, as shown inFIG.2, can include a head portion17at the end of the shaft16which is received in the housing14. The housing14can be pivotable relative to the head portion17of the shaft16. In other instances, the pedicle screw12can be mono-axial or mono-planar, if desired.

The pedicle screw12can include a securing element, such as a threaded fastener20(e.g., a set screw, cap) configured to rotatably engage the housing14to secure a portion of a support construct22to the pedicle screw12. For example, the threaded fastener20can include threads which mate with threads formed in the housing14. In other embodiments, the fastener20can include one or more flanges, cam surfaces, or other engagement features that engage with one or more channels, grooves, surfaces, or other engagement features of the housing14through rotation of the fastener20. The fastener20can be rotatably engaged between spaced apart legs of the housing14which define the channel15of the housing14therebetween.

The spinal stabilization system10can also include one or more, or a plurality of support constructs22extending between pedicle screws12of the spinal stabilization system10. As an illustrative example, the spinal stabilization system10shown inFIG.1includes a support construct22extending between the first pedicle screw12aand the second pedicle screw12b.

The support construct22can be constructed of a plurality of components in some instances. For instance, the support construct22can include a spacer24, and a flexible member such as a flexible cord30extending through the spacer24, as well as other components if desired.

In some embodiments, the spacer24can be an annular spacer having a lumen (not shown) extending from a first end26to a second end28of the spacer24. For example, in some embodiments the spacer24can be a cylindrical member having a lumen extending therethrough. In other embodiments, the spacer24can be molded, extruded, or otherwise formed over and/or around the cord30. The spacer24can be positioned between the housing14of the first pedicle screw12aand the housing14of the second pedicle screw12b. In some embodiments, the spacer24can be formed from polycarbonate urethane (PCU), although it will be recognized that various other materials suitable for implantation within the human body and for providing stabilization of the spine while maintaining flexibility can be used. In other embodiments, the spacer24can be constructed of other materials such as metal, polymeric materials, or combinations of materials.

The cord30can extend from the housing14of the first pedicle screw12ato the housing14of the second pedicle screw12b. In one embodiment, the cord30can be formed from polyethylene-terephthalate (PET), although it will be recognized that various other materials suitable for implantation within the human body and for providing stabilization of the spine while maintaining flexibility can be used. In other embodiments, the cord30can be constructed of other flexible materials such as metal, polymeric materials, or combinations of flexible materials. It is noted that during a medical procedure the portions of the cord30which are shown extending from the channels of the pedicle screws12a,12bcan be trimmed as desired to reduce and/or eliminate the portion of the cord30extending from the pedicle screws12a,12b.

When implanted in a patient, the cord30of the spinal stabilization system10can limit the range of flexion of the spinal segment, whereas the spacer24can limit the range of extension of the spinal segment. For instance, the cord30can be placed in tension and the spacer24can be placed in compression between the pedicle screws12a,12b.

The spinal stabilization system10can also include inserts32configured to be inserted into the channels15of the housings14of the pedicle screws12. One possible embodiment of the insert32is further illustrated inFIGS.3and4. The inserts32, which can be considered spools in some instances, can include a first flange34proximate a first end of the insert32, a second flange36proximate the second end of the insert32, and a medial portion38intermediate the first flange34and the second flange36and extending therebetween. The insert32can have end surfaces48configured to abut an end surface of the spacer24. For instance, when assembled an end surface48of an insert32coupled with the first pedicle screw12acan abut an end surface of the spacer24proximate the first end26of the spacer24and an end surface48of an insert32coupled with the second pedicle screw12bcan abut an end surface of the spacer24proximate the second end28of the spacer24.

The insert32can be configured such that the medial portion38is positionable in the channel15(shown inFIG.2) of the housing14of the pedicle screw12with the first flange34positioned exterior of the housing14and facing the first side of the housing14and the second flange36positioned exterior of the housing14and facing the second side of the housing14. The insert32can be positioned in the channel15in a top-loaded fashion in which the insert32is moved into the channel15of the housing14in a direction generally perpendicular to the longitudinal axis of the channel15of the housing14.

The insert32can include bore40extending from a first end surface48at the first end of the insert32to a second end surface48at the second end of the insert32along a longitudinal axis through the insert32. The bore40can be configured to receive the cord30therein. For instance, the cord30can be inserted into and/or through the bore40of the insert32. Thus, the cord30can extend out of the bore40from the first end surface48at the first end of the insert32in a first direction and/or the cord30can extend out of the bore40from the second end surface48at the second end of the insert32in a second direction opposite the first direction.

The insert32can include a clamping member50configured to clamp or secure the cord30within the bore40of the insert32. For example, the clamping member50can be inserted into an opening42in the medial portion38of the insert32to bear against the cord30. The opening42can intersect with the bore40to provide direct engagement of the clamping member50with a portion of the cord30positioned in the bore40. In some instances, the insert32can be press fit in the opening42. As shown inFIG.3, in some instances, the clamping member50can be inserted into the opening42until the exterior surface of the clamping member50is flush with an exterior surface of the medial portion38of the insert32.

The clamping member50can include any mechanical gripping means such as, but not limited to, one or more ribs, projecting grooves, teeth, posts, spikes, and/or serrations or combination thereof for engaging and/or penetrating into the cord30. In the illustrated embodiment, the clamping member50can include a generally concave engagement surface44having a plurality of ribs, teeth, serrations, grooves, or other gripping features formed along the concave surface44, configured to engage and/or penetrate into the cord30. As shown inFIG.5A, the concave engagement surface44can be configured to engage the periphery of the cord30, such as 30 degrees or more, 45 degrees or more, 60 degrees or more, 75 degrees or more, or 90 degrees or more around the periphery (e.g., circumference) of the cord30when engaging the cord30in the bore40.

In some instances, the cord30can be pre-assembled with the insert32and secured in the bore40with the clamping member50by pressing the clamping member50against the cord30prior to inserting the insert32into the channel15of the housing14of the pedicle screw12. Additionally or alternatively, the cord30can be intra-operatively secured in the bore40with the clamping member50while securing the insert32in the channel15of the housing14of the pedicle screw12with the fastener20.

One exemplary configuration for securing the cord30in the bore40while simultaneously locking the housing14of the poly-axial pedicle screw12from pivotal movement is shown inFIGS.5A and5B.

As shown inFIG.5A, the insert32can be inserted into the channel15of the housing14in a direction generally perpendicular to the longitudinal axis of the bore40. The cord30, extending into or through the bore40of the insert32, can also be inserted into the channel15of the housing14with the cord30extending from the first side of the housing14and/or extending from the second side of the housing14. Thus, the medial portion38of the insert32can be positioned within the U-shaped channel15.

The fastener20can then be engaged with the housing14, such as through rotational movement of the fastener20relative to the housing14. In some instances, the fastener20can include a threaded portion which threadably engages a threaded portion of the housing14, such as internally threaded portions of opposing legs of the housing14defining the channel15. Rotational movement of the fastener20moves the fastener20into engagement with the insert32.

As shown inFIG.5B, rotational engagement of the fastener20with the housing14causes the fastener20to directly contact the clamping member50to exert a force on the clamping member50to push the clamping member50toward the cord30. The amount of rotation of the fastener20, and thus axial movement of the fastener20along its axis of rotation, controls the displacement of the clamping member50in the opening42toward the cord30. The concave surface44of the clamping member50can contact a portion of the periphery (e.g., circumference) of the cord30, such as 5% or more, 10% or more, 15% or more, 20% or more, or 25% or more of the periphery of the cord30. Deformation of the cord30and/or penetration into the cord30by the clamping member50can prevent the cord30from moving axially through the bore40of the insert32.

In some instances, the clamping force generated through rotational engagement of the fastener20with the housing14both clamps the cord30to the insert32(and thus secures the cord30to the pedicle screw12) and locks the housing14from pivotal movement relative to the shaft16of the pedicle screw12. For instance a locking force exerted by the fastener20can be transmitted through the insert32to the head portion17of the shaft16to lock the housing14from pivotable movement relative to the head portion17of the shaft16. When the clamping force is sufficiently large, the clamping force exerted onto the head portion17by the insert32locks the housing14from pivotal movement relative to the head portion17.

As shown inFIGS.6A-6C, the end surfaces48of the insert32can be oriented at any desired angle relative to the longitudinal axis of the bore40extending through the insert32. For example, inFIG.6A, the both the first and second end surfaces48of the insert32can be generally perpendicular to the longitudinal axis of the bore40. In other instances, one or more of the end surfaces48can be oriented at an oblique angle to the longitudinal axis of the bore40, such as for use in lordotic applications. For example, inFIG.6B, the first end surface48of the insert32can be at an oblique angle θ to the longitudinal axis of the bore40, while the second end surface48of the insert can be generally perpendicular to the longitudinal axis of the bore40. Alternatively, inFIG.6C, the first end surface48of the insert32can be at an oblique angle θ1to the longitudinal axis of the bore40and the second end surface48of the insert32can be at an oblique angle θ2to the longitudinal axis of the bore40. The angles θ1and θ2can be the same or different. The angles θ1, θ2and/or θ can be any desired angle, such as 2°, 3°, 4°, 5°, 6°, 7°, 8°, 9° or 10°, for example. It is note that any of the embodiments of an insert described herein can include end surfaces which are perpendicular and/or oblique to the longitudinal axis of the bore extending through the insert.

Another embodiment of an insert132configured for securement of the cord30within the housing14of a pedicle screw12or other vertebral anchor is illustrated inFIGS.7-9. The insert132can be similar to the insert32in many respects. For example, the insert132can include a first flange134proximate a first end of the insert132, a second flange136proximate the second end of the insert132, and a medial portion138intermediate the first flange134and the second flange136and extending therebetween. The insert132can have end surfaces148configured to abut an end surface of the spacer24. The insert132can be configured such that the medial portion138is positionable in the channel15of the housing14of the pedicle screw12with the first flange134positioned exterior of the housing14and facing the first side of the housing14and the second flange136positioned exterior of the housing14and facing the second side of the housing14.

The insert132can include bore140extending from a first end surface148at the first end of the insert132to a second end surface148at the second end of the insert132along a longitudinal axis through the insert132. The bore140can be configured to receive the cord30therein.

The insert132can include a clamping member150configured to clamp or secure the cord30within the bore140of the insert132. For example, the clamping member150can be movable relative to the medial portion138of the insert132to bear against the cord30and clamp the cord30therebetween. The clamping member150can include a first tab152extending into a channel146in the first flange134and a second tab152extending into a channel146in the second flange136. The tabs152can move along the channels146as the clamping member150is moved toward the cord30to clamp the cord30in the bore140. In some instances, such as shown inFIG.8, the tabs152can form an interference fit with the channels146such that walls of the tabs152frictionally engage walls of the channels146to resist movement of the clamping member150relative to the medial portion138of the insert132unless and until the force sufficient to overcome the frictional/interference force is overcome. As shown inFIG.9, in some instances the upper portion of the channels146can have a width W1and a lower portion of the channels146can have a width W2greater than the width W1. The tabs152can have a width greater than the width W1to provide an interference fit in the upper portion of the channel146. However, the width of the tabs152can be less than the width W2of the lower portion of the channel146. Thus, as shown inFIG.10A, the clamping member150can be initially positioned in a first, loading position with the tabs152forming an interference fit in the upper portion of the channel146, retaining the clamping member150in the loading position such that the clamping member150does not interfere with positioning the cord30into and/or through the bore140of the insert132. Upon applying sufficient force to the clamping member150to overcome the frictional force (e.g., tightening the fastener20in the housing14of the pedicle screw12to apply a force against the clamping member150), the tabs152move into the wider lower portion of the channel146to the clamped position, shown inFIG.10B, with the clamping member150engaging and/or penetrating into the cord30to secure the cord30in the bore140of the insert132.

It is noted that other configurations are contemplated for initially holding the clamping member150in a loading position to facilitate positioning the cord30in the bore140. For example, detents can be incorporated with the tabs152/channels146to form an interference between the components.

The clamping member150can include any mechanical gripping means such as, but not limited to, one or more ribs, projecting grooves, teeth, posts, spikes, and/or serrations or combination thereof for engaging and/or penetrating into the cord30. In the illustrated embodiment ofFIGS.10A-10C, the clamping member150can include a generally concave engagement surface having a plurality of ribs, teeth, serrations, grooves, or other gripping features formed along the concave surface, configured to engage and/or penetrate into the cord30. The concave engagement surface can be configured to engage the periphery of the cord30, such as 30 degrees or more, 45 degrees or more, 60 degrees or more, 75 degrees or more, or 90 degrees or more around the periphery (e.g., circumference) of the cord30when engaging the cord30in the bore140.

Additionally or alternatively to the embodiment ofFIGS.10A-10C, the medial portion138of the insert132can include any mechanical gripping means such as, but not limited to, one or more ribs, projecting grooves, teeth, posts, spikes, and/or serrations or combination thereof for engaging and/or penetrating into the cord30. In the illustrated embodiment ofFIG.12B, the medial portion138can include a generally concave engagement surface having a plurality of ribs, teeth, serrations, grooves, or other gripping features formed along the concave surface, configured to engage and/or penetrate into the cord30. The concave engagement surface can be configured to engage the periphery of the cord30, such as 30 degrees or more, 45 degrees or more, 60 degrees or more, 75 degrees or more, or 90 degrees or more around the periphery (e.g., circumference) of the cord30when engaging the cord30in the bore140.

In some instances, the cord30can be pre-assembled with the insert132and secured in the bore140with the clamping member150by pressing the clamping member150against the cord30prior to inserting the insert132into the channel15of the housing14of the pedicle screw12. Additionally or alternatively, the cord30can be intra-operatively secured in the bore140with the clamping member150while securing the insert132in the channel15of the housing14of the pedicle screw12with the fastener20.

FIG.10Cillustrates another possible orientation of the insert132positioned in the channel of the housing14of a pedicle screw (shown in phantom). As shown inFIG.10C, in some instances the insert132can be positioned in the channel of the housing14of the pedicle screw12with the clamping member150below or distal the medial region138of the insert132, with the flanges134,136positioned on opposite sides of the housing14, if desired. Upon applying sufficient force to the clamping member150to overcome the frictional force between the tabs152and channels146(e.g., tightening the fastener20in the housing14of the pedicle screw12to apply a force against the medial region138), the medial region138and first and second flanges134,136move downward relative to the housing14to clamp the cord30between the medial region138and clamping member150. As the medial region138and flanges134,136move relative to the housing14and clamping member150, the tabs152move into the wider lower portion of the channel146to the clamped position, with the clamping member150engaging and/or penetrating into the cord30to secure the cord30in the bore140of the insert132. Accordingly, in some instances the fastener20can bear against the medial region138of the insert132while the clamping member150can bear against a component of the housing14, for example.

FIGS.11A and11Billustrate insert132′, which is a variation of the insert132. Unlike the embodiment ofFIGS.7-8, in which the channels146extend to the outer peripheral edge of the flanges134,136, in the variation ofFIGS.11A and11B, the channels146may not extend to the outer peripheral edge of the flanges134,136. Such an embodiment can help retain the clamping member150assembled with the main body of the clamping member150during assembly of the construct.FIGS.12A and12Billustrate insert132″, which is a variation of the insert132′ illustrating that the width of the channels146and tabs152can be up to about the diameter of the bore140.

FIGS.13A and13Billustrate insert132′, which is a variation of the insert132″. Unlike the embodiment ofFIGS.12A-12B, in which the channels146and tabs152each have a uniform width, in the variation ofFIGS.13A and13B, the upper portion of the channels146can have a protuberance extending radially towards the bore140and the tabs152can have a void disposed therein that receives the protuberance in mating engagement.

It is noted that in other instances, the insert132,132′ can include channels at opposing ends of the clamping member150configured to mate with and receive projections extending into the channels from the flanges134,136. In other instances, the insert132,132′ can include a channel at a first end of the clamping member150configured to mate with and receive a projection extending into the channels from one of the flanges134,136and a tab extending from the opposite, second end of the clamping member150configured to mate with and extend into a channel in the other of the flanges134,136.

Another embodiment of an insert232configured for securement of the cord30within the housing14of a pedicle screw12or other vertebral anchor is illustrated inFIG.13. The insert232can be similar to the insert32in many respects. For example, the insert232can include a first flange234proximate a first end of the insert232, a second flange236proximate the second end of the insert232, and a medial portion238intermediate the first flange234and the second flange236and extending therebetween. The insert232can have end surfaces248configured to abut an end surface of the spacer24. The insert232can be configured such that the medial portion238is positionable in the channel15of the housing14of the pedicle screw12with the first flange234positioned exterior of the housing14and facing the first side of the housing14and the second flange236positioned exterior of the housing14and facing the second side of the housing14.

The insert232can include bore240extending from a first end surface248at the first end of the insert232to a second end surface248at the second end of the insert232along a longitudinal axis through the insert232. The bore240can be configured to receive the cord30therein.

The insert232can include an opening242in the medial portion238of the insert232for receiving a clamping member to bear against the cord30. The opening242can intersect with the bore240to provide direct engagement of the clamping member with a portion of the cord30positioned in the bore240. The clamping member can be a fastener220, such as a threaded set screw including threads which mate with threads formed in the housing14. The fastener220can be rotatably engaged between spaced apart legs of the housing14to apply a clamping force to the cord30to clamp or secure the cord30within the bore240of the insert232while simultaneously clamping the insert232in the housing14of a pedicle screw12. For example, the fastener220can include a threaded portion226and a protuberance224extending from the threaded portion226. The protuberance224can extend into the opening242to bear against the cord30and clamp the cord30in the bore240.

The insert232can also include recesses260formed in the flanges234,236of the insert232to accommodate the fastener220therebetween. For instance, as shown inFIG.16, the fastener220can have an outer diameter greater than the distance between the first flange234and the second flange236(i.e., the distance between the inner surfaces of the flanges234,236facing the medial portion238. Thus, the recesses260can provide clearance for the fastener220to be rotatably engaged with the housing14of the pedicle screw12between the first and second flanges234,236. Furthermore, the recesses260can allow for a degree of rotational variability of the insert232(about the longitudinal axis of the bore240) relative to the housing14when positioning and securing the insert232in the housing14.

FIG.15illustrates a support construct222utilizing inserts232. The support construct222can also include spacers24and a flexible member such as a flexible cord30extending through the spacers24, as well as other components if desired. The inserts232are shown positioned in the housing14of the pedicle screws12, with spacers24positioned between facing surfaces of the inserts232. The flexible cord30can extend through the bores240of the inserts232and the lumen of the spacers24. The fasteners220can be threadably engaged with the housing14of the pedicle screws12to secure the inserts232to the housing14while the protuberance224of the inserts232can simultaneously engage the cord30to secure the cord30relative to the insert232and housing14.

Furthermore, the end of the cord30can be secured to a rigid rod member270, providing a transition between the dynamic or flexible portion of the construct222and a rigid portion of the construct222. The rigid rod270can extend to one or more additional pedicle screws (not shown), for example.

The rigid rod member270can include an end region configured to be secured to an end region of the cord30. For example, end region of the rigid rod member270can be configured as a clam shell connector having a plurality of segments272collectively defining a bore for receiving the end region of the cord30. The segments272can extend from a flange274of the rigid rod member270positionable on a first side of the housing14of the pedicle screw12. The free ends of the segments272can move toward one another (e.g., radially inward toward the central longitudinal axis of the cord30to clamp around the cord30. For example, a clamping force can be exerted on the segments272to move the free ends toward one another. A retaining ring276can be slid over the cord30and placed around the free ends of the segments272to secure the cord30and prevent the free ends of the segments272from separating. The segments272of the clam shell connector can be positioned in the channel of the housing14of the pedicle screw12with the flange274on a first side of the housing14and the retaining ring276on a second, opposite side of the housing14. The retaining ring276can act as a flange for engagement with a spacer24of the support construct222.

Components of another exemplary support construct322utilizing inserts332are shown inFIG.17. It is noted that the inserts332can be substituted with any other configuration of insert described herein, if desired. The support construct322includes inserts332for securement in the housings14of pedicle screws12or other vertebral anchors, as well as spacers24and a flexible member such as a flexible cord30extending through the spacers24and secured in the inserts332.

The inserts332can be similar to the other inserts332described herein in many respects. For example, the inserts332can include a first flange334proximate a first end of the insert332, a second flange336proximate the second end of the insert332, and a medial portion338intermediate the first flange334and the second flange336and extending therebetween. The insert332can be configured such that the medial portion338is positionable in the channel15of the housing14of the pedicle screw12with the first flange334positioned exterior of the housing14and facing the first side of the housing14and the second flange336positioned exterior of the housing14and facing the second side of the housing14.

The insert332can include bore340extending from a first end surface at the first end of the insert332to a second end surface at the second end of the insert332along a longitudinal axis through the insert332. The bore340can be configured to receive the cord30therein.

The insert332can include one or more, or a plurality of openings342in the medial portion338of the insert332for receiving a clamping member to bear against the cord30. The openings342can intersect with the bore340to provide direct engagement of the clamping member with a portion of the cord30positioned in the bore340. The clamping members can be pins350press fit, or otherwise positioned in the openings342.

The insert332can also include recesses360formed in the flanges334,336of the insert332to accommodate the fastener20therebetween. For instance, as shown inFIG.19, the fastener20can have an outer diameter greater than the distance between the first flange334and the second flange336(i.e., the distance between the inner surfaces of the flanges334,336facing the medial portion338. Thus, the recesses360can provide clearance for the fastener20to be rotatably engaged with the housing14of the pedicle screw12between the first and second flanges334,336.

FIG.18Aillustrates a support construct322utilizing inserts332. The support construct322can also include spacers24and a flexible member such as a flexible cord30extending through the spacers24, as well as other components if desired. The inserts332are shown positioned in the housing14of the pedicle screws12, with spacers24positioned between adjacent inserts332. The flexible cord30can extend through the bores340of the inserts332and the lumen of the spacers24. The fasteners20can be threadably engaged with the housing14of the pedicle screws12to secure the inserts332to the housing14. In some instances, the fasteners20can drive the pins350into clamping engagement with the cord30as the fasteners20are threadably engaged with the housing14of the pedicle screw12. In other instances, the drive pins350can be pressed against the cord30prior to inserting the inserts332into the housing14of the pedicle screw12.

The support construct322can also include one or more rings380positionable between an end surface of an insert332and an end surface of a spacer24. In some instances, the use of the ring380can between the insert332and the spacer24can provide a desired amount of angulation between the longitudinal axis of the bore340of the insert332relative to the lumen of the spacer24such that the central axis of the lumen of the spacer24extends non-parallel (e.g., oblique) to the central axis of the bore340of the insert332.

As shown in the enlarged view ofFIG.18B, the ring380can include an annular portion382with an opening388extending axially through the annular portion382for receiving the cord30therethrough. The annular portion382can have a first face392configured to face and abut an end surface of a flange of the insert332and an opposite, second face394configured to face and abut an end surface of a spacer24. The first face392can be non-parallel to the second face394providing the annular portion382with a wedge-shape. The angle between the first face392and the second face394can be any desired angle, such as 2°, 3°, 4°, 5°, 6°, 7°, 8°, 9° or 10°, for example.

In some instances the ring380can include an annular projection384extending from the second face394of the annular portion382. The opening388can extend through the annular projection384, and thus the cord30can extend through the annular projection384. The annular projection384can be configured to extend into the lumen of the spacer24, such as an enlarged recessed portion at an end region of the spacer24. Additionally or alternatively, the ring380can include annular projection386extending from the first face392of the annular portion382. The opening388can extend through the annular projection386, and thus the cord30can extend through the annular projection386. The annular projection386can be configured to extend into the bore340of the insert332, such as an enlarged recessed portion in a flange of the insert332.

In some instances, the ring380can include an engagement feature configured to mate with an engagement feature of the insert332and/or the spacer24to orient the ring380at a desired rotational position relative to the insert332positioned on a first side of the ring380and/or the spacer24positioned on a second side of the ring380.

FIGS.20and21illustrate components of another support construct422including a rigid segment coupled to a flexible segment. The support construct422can include an insert432positionable in the housing14of a pedicle screw12or other vertebral anchor, forming a transition between a rigid segment and a flexible segment of the support construct422. For example, the rigid segment can include a rigid rod member470and the flexible segment can include a spacer24, and a flexible member such as a flexible cord30extending through the spacer24, as well as other components if desired. The end of the cord30can be secured to the rigid rod member470, via the insert432, providing a transition between the dynamic or flexible portion of the construct422and the rigid portion of the construct422.

The insert432can include a first flange434and a second flange436spaced from the first flange434by a medial region438. The medial region438can have a cross-sectional dimension less than the cross-sectional dimension of each of the first and second flanges434,436. For instance, the medial region438can be sized for insertion into the U-shaped channel of the housing14of a pedicle screw12or other vertebral anchor, with the first flange434located exterior of the housing14on a first side of the housing14and the second flange436located exterior of the housing14on a second side of the housing14, similar to other inserts described herein.

The rigid rod member470can extend from the second flange436. In some instances the rigid rod member470can be integrally formed with the insert432as a monolithic construct, however, in other instances the rigid rod member470can be a separate component attached to the insert432, for example. The rigid rod470can be sized to extend to one or more additional pedicle screws (not shown), for example. The rigid rod470can be any desired length, such as a length sufficient to extend between two, three, four, or more pedicle screws12secured to corresponding vertebrae of the spinal column.

The insert432can include a bore440extending into the medial region438from the first flange434for receiving a portion of the flexible cord30, such as an end portion of the flexible cord30. The insert432can also include a clamping member450configured to clamp or secure the cord30within the bore440of the insert432. For example, the clamping member450can be movable relative to the medial portion438of the insert432to clamp the cord30between the clamping member450and the medial portion438.

The clamping member450can be constructed similar to the clamping member150, discussed above. For example, the clamping member450can include a first tab452extending into a channel446in the first flange434and a second tab452extending into a channel446in the second flange436. The tabs452can move along the channels446as the clamping member450is moved toward the cord30to clamp the cord30in the bore440. In some instances, the tabs452can form an interference fit with the channels446such that walls of the tabs452frictionally engage walls of the channels446to resist movement of the clamping member450relative to the medial portion438of the insert432unless and until the force sufficient to overcome the frictional/interference force is overcome.

The clamping member450can include any mechanical gripping means such as, but not limited to, one or more ribs, projecting grooves, teeth, posts, spikes, and/or serrations or combination thereof for engaging and/or penetrating into the cord30, in the illustrated embodiment, the clamping member450can include one or more, or a plurality of protuberances454configured to engage and/or penetrate into the cord30.

It is noted that the insert432can alternatively be constructed to use any other clamping member to secure the cord30in the bore440, such as any of the other clamping members described herein. Furthermore, it is noted that any of the other inserts described herein can include a rigid rod portion extending from one end of the insert for forming a rigid construct between two or more vertebrae.

FIG.21is a cross-sectional view of the support construct422in an assembled configuration, with the medial portion438positioned in the U-shaped channel of the housing14of a pedicle screw12and the flanges434,436positioned on either side of the housing14. In the assembled configuration, an end portion of the flexible cord30is positioned in the bore440of the insert432and the clamping member450is pressed into engagement with the cord30with the fastener20.

The fastener20can then be engaged with the housing14, such as through rotational movement of the fastener20relative to the housing14. In some instances, the fastener20can include a threaded portion which threadably engages a threaded portion of the housing14, such as internally threaded portions of opposing legs of the housing14defining the channel15. Rotational movement of the fastener20moves the fastener20into engagement with the clamping member450.

Although not shown, the rigid rod member470can extend to one or more additional pedicle screws which can be secured to corresponding vertebrae of the spinal column. Furthermore, the cord30can extend in an opposite direction from the insert432to one or more additional pedicle screws which can be secured to vertebrae of the spinal column. Furthermore, a spacer24, such as that shown inFIG.20, can be positioned between the flange434and another insert432and/or pedicle screw with the flexible cord30extending through the spacer24, to provide a flexible construct at one or more vertebral levels.

Another spinal fixation system510for stabilizing a portion of a spinal column, such as one or more spinal segments of a spinal column is shown inFIG.22. The spinal stabilization system510can include one or more or a plurality of vertebral anchors, depicted as pedicle screws12, configured to be secured to a vertebra of a spinal column. The pedicle screws12can include a housing14and a shaft16, which can include threads, extending from the housing14. The pedicle screws12can be poly-axial, mono-axial or mono-planar, if desired. As shown in the cross-sectional view ofFIG.23A, the pedicle screws12can be cannulated (e.g., the threaded shaft16can having a central lumen extending longitudinally therethrough) to be delivered to the anatomy over a K-wire590.

The pedicle screw12can include a securing element, such as a threaded fastener520(e.g., a set screw, cap) configured to rotatably engage the housing14to secure a portion of a support construct522to the pedicle screw12. The fastener520can be rotatably engaged between spaced apart legs of the housing14which define a channel of the housing14therebetween. The fastener520can also be cannulated to be advanced to the housing14of the pedicle screw along a K-wire590

The spinal stabilization system510can also include one or more, or a plurality of support constructs522extending between pedicle screws12of the spinal stabilization system510. The support construct522can be constructed of a plurality of components in some instances. For instance, the support construct522can include spacers24, and a plurality of flexible members such as a first flexible cord530aand a second flexible cord530bextending through the spacers24, as well as other components if desired. The cords530a,530bcan extend from the housing14of the first pedicle screw12to the housing14of the second pedicle screw12.

In some embodiments, the spacers24can have a lumen extending from a first end to a second end of the spacer24, as shown inFIG.23A, for receiving the first and second flexible cords530a,530btherethrough. In other instances, the spacers24can include a plurality of lumens extending therethrough, each configured to receive a separate one of the plurality of flexible cords, for example. For instance, the spacer can include a first lumen configured to receive the first flexible cord530aand a second lumen configured to receive the second flexible cord530b, maintaining the first and second flexible cords530a,530bisolated from one another through the spacer24.

When implanted in a patient, the cords530a,530bof the spinal stabilization system510can limit the range of flexion of the spinal segment, whereas the spacers24can limit the range of extension of the spinal segment. For instance, the cords530a,530bcan be placed in tension and the spacers24can be placed in compression between the pedicle screws12.

The spinal stabilization system510can also include inserts532configured to be inserted into the channels of the housings14of the pedicle screws12. The insert532is further illustrated inFIGS.24-26. The inserts532, which can be considered spools in some instances, can include a first flange534proximate a first end of the insert532, a second flange536proximate the second end of the insert532, and a medial portion538intermediate the first flange534and the second flange536and extending therebetween. The insert532can have end surfaces548configured to abut an end surface of the spacers24. For instance, when assembled an end surface548of an insert532coupled with the first pedicle screw12can abut an end surface of the spacer24proximate the first end of the spacer24and an end surface548of an insert532coupled with the second pedicle screw12can abut an end surface of the spacer24proximate the second end of the spacer24.

The insert532can be configured such that the medial portion538is positionable in the channel of the housing14of the pedicle screw12with the first flange534positioned exterior of the housing14and facing the first side of the housing14and the second flange536positioned exterior of the housing14and facing the second side of the housing14.

The insert532can include a plurality of bores extending therethrough, such as a first bore540aand a second bore540b, each extending from a first end surface548at the first end of the insert532to a second end surface548at the second end of the insert532. As shown inFIG.26, the first bore540acan extend generally parallel to and spaced apart from the second bore540b, Each of the bores540a,54bcan be configured to receive one of the cords530a,530btherein. For instance, the first cord530acan be inserted into and/or through the first bore540aof the insert532and the second cord530bcan be inserted into and/or through the second bore540bof the insert532.

The insert532can include an opening542in the medial portion538of the insert532for receiving a clamping member to bear against the cords530a,530b. As shown inFIG.25, the opening542can intersect with each of the first and second bores540a,540bto provide direct engagement of the clamping member with a portion of each of the first and second cords530a,530bpositioned in the bores540a,540b, respectively. In some instances, the insert532can include a lower portion543of the opening542extending below the first and second bores540a,540bsuch that the opening542extends entirely through the insert532from an upper surface to a lower surface of the medial portion538to accommodate the K-wire590extending through the opening542of the insert532, as shown inFIG.23A. In some instances, the insert532can be positioned in the channel of the housing14of the pedicle screw12with the first and second cords530a,530bextending through the first and second bores540a,540bof the insert532by advancing the insert532along the K-wire590(i.e., with the K-wire590extending through the opening542) while the K-wire590is positioned through the longitudinal lumen extending through the shaft16of the pedicle screw12and the opening542through the insert532. The K-wire590can extend through the opening542of the insert532with the K-wire590positioned between the first and second cords530a,530b. Thus, the longitudinal lumen extending through the shaft16of the pedicle screw12and the opening542through the insert532can be coaxially aligned, in some instances.

The clamping member can be a fastener520, such as a threaded set screw including threads which mate with threads formed in the housing14. The fastener520can be rotatably engaged between spaced apart legs of the housing14to apply a clamping force to the first and second cords530a,530bto clamp or secure the cords530a,530bwithin the first and second bores540a,540bof the insert532while simultaneously clamping the insert532in the housing14of a pedicle screw12. For example, as shown inFIGS.23B and27, the fastener520can include a threaded portion226and a protuberance224extending from the threaded portion226. As shown inFIG.27, the protuberance224can extend into the opening542to bear against each of the first and second cords530a,530band simultaneously clamp the first and second cords530a,530bin the first and second bores540a,540b, respectively. In some instances, the cords530a,530bcan be clamped in the insert532with the fastener520while the K-wire590is positioned through the longitudinal lumen extending through the shaft16of the pedicle screw12, the opening542through the insert532, and the opening528through the fastener520. Thus, the longitudinal lumen extending through the shaft16of the pedicle screw12, the opening542through the insert532, and the opening528through the fastener520can be coaxially aligned, in some instances.

Those skilled in the art will recognize that the present invention may be manifested in a variety of forms other than the specific embodiments described and contemplated herein. Accordingly, departure in form and detail may be made without departing from the scope and spirit of the present invention as described in the appended claims.