Patent Description:
Common procedures for handling pain associated with intervertebral discs that have become degenerated due to various factors such as trauma or aging may include the use of pedicle screw fixation and/or intervertebral fusion for fusing one or more adjacent vertebral bodies. Generally, bilateral pedicle screw fixation, for example, with a rod construct, may be used to treat degenerative disc disease and a multitude of other spine pathologies as a standard of treatment to stabilize two or more adjacent vertebral bodies, for example, as an adjunct to spinal fusion.

Unfortunately, a number of iatrogenic pathologies are associated with pedicle screw fixation including, but not limited to, misplacement of screws, muscle/ligamentous disruption during insertion, adjacent segment disease due to superior adjacent facet violation by the inferior pedicle screw construct, increased procedural time, and/or instrumentation failure. There exists a clinical need for a fixation system and method that reduces the iatrogenic effects of a bilateral pedicle screw construct from a posterior approach while stabilizing two adjacent vertebral bodies that may be used as an adjunct to spinal fusion.

<CIT> describes a device known in the art. Further intradiscal devices of the known art are disclosed in <CIT>, <CIT>, <CIT>.

In accordance with the application, pedicle-based intradiscal devices and systems are provided. In particular, pedicle-based intradiscal fixation may be used as one or more standalone devices or may be used in conjunction with an interbody fixation device. The method of fixation, that is not part of the invention, may include inserting the device through the pedicle of an inferior vertebra, into the vertebral body of the inferior vertebra, through the disc space, and securing the device to the vertebral body of the adjacent superior vertebra. The pedicle-based intradiscal fixation devices described herein may improve access-related morbidity while providing sufficient stabilization force for spinal fusion.

The invention is defined in the independent claim <NUM>, further advantageous embodiments of the invention are set forth in the dependent claims.

According to the present invention, a pedicle-based intradiscal implant for stabilizing an inferior vertebra and a superior vertebra includes a bendable rod, a bone fastener, and a locking cap. The bendable rod extends from a proximal end having an outer threaded portion to a distal end with a sharp tip configured to engage bone. The bone fastener has a threaded screw head and a shaft extending along a central longitudinal axis. The bone fastener defines a channel for receiving the bendable rod. The channel has a straight portion extending along the central longitudinal axis and a curved portion with an exit through a sidewall of the shaft. The locking cap includes an internally threaded seat for engaging with the screw head of the bone fastener and a central protrusion defining a cavity for receiving the proximal end of the bendable rod.

The pedicle-based intradiscal implant may include one or more of the following features. The locking cap may have a cylindrical body defining a drive recess opposite to the internally threaded seat. The cavity in the central protrusion of the locking cap may be non-threaded and configured to push the rod forward, thereby compressing the rod securely. Alternatively, the cavity in the central protrusion of the locking cap may be threaded and configured to mate with the outer threaded portion of the bendable rod, thereby pulling the rod backward to secure the rod. The straight portion of the channel may extend through the screw head and along the shaft toward a distal end of the bone fastener and the curved portion of the channel may be located near the distal end of the bone fastener. The bendable rod may be flexible such that the rod has a straight configuration and is bendable into a curved configuration. In the curved configuration, the bendable rod may have a straight portion and a curved portion where the rod is curved in an arc up to <NUM>°. The bendable rod may be formed of a shape-memory material, such as nitinol. A distal portion of the bendable rod may have a polygonal cross-section with planar faces and a proximal portion of the bendable rod may have a cylindrical shape. The bone fastener may be a pedicle screw with a proximal end including a recess configured to receive an instrument for inserting the pedicle screw and a distal end with a tip configured to be inserted into the pedicle of the inferior vertebra.

It is further described but it is not part of the invention, a hybrid implant suitable for use with a revision procedure may include a bendable rod configured to engage bone, a bone fastener, a locking cap, and a tulip head coupled to the locking cap. The bone fastener has a screw head and a shaft. The bone fastener defines a channel for receiving the bendable rod. The channel has a straight portion extending through the screw head and along a portion of the shaft and a curved portion with an exit through a sidewall of the shaft. The locking cap defines an internal seat for engaging with the screw head of the bone fastener and a central protrusion defining a cavity for receiving one end of the bendable rod. The tulip head has a body with a pair of opposed arms defining a rod slot sized and configured to accept a spinal rod.

The hybrid implant may include one or more of the following features. The tulip head may be integrally coupled to the locking cap with a rigid arm. The tulip head may be offset laterally to the locking cap. The rod slot of the tulip head may be aligned in parallel to the bendable rod. The screw head may be externally threaded and the internal seat of the locking cap may be internally threaded to thereby threadedly interface with the screw head.

It is further described but it is not part of the invention a method for stabilizing an inferior vertebra and a superior vertebra may include one or more of the following steps in any suitable order: (<NUM>) posteriorly accessing a spine of a patient; (<NUM>) inserting a fastener having a head and a shaft into a pedicle of the inferior vertebra and into a vertebral body of the inferior vertebra; (<NUM>) moving a rod through a channel in the fastener such that a distal portion of the rod curves through the channel and outside the fastener into the vertebral body of the inferior pedicle, through a disc space, and into a vertebral body of the superior vertebra; and (<NUM>) threading a locking cap onto the head of the fastener and into engagement with the rod to thereby secure the positioning of the fastener and the rod. The fastener and rod may be deployed simultaneously or the fastener may be deployed first and the rod subsequently. The method may include, before moving the rod through the channel in the fastener, attaching an instrument to a proximal end of the rod with a threaded interface. The method may include, before moving the rod through the channel in the fastener, straightening the rod. The method may include installing two implants including a first fastener and first rod deployed from an ipsilateral pedicle of the inferior vertebra, and a second fastener and second rod deployed through the contralateral pedicle of the inferior vertebra.

There are also described but do not form part of the invention, kits including pedicle-based intradiscal fixation devices of varying types and sizes, interbody fusion devices of varying types and sizes, rods, fasteners or anchors, k-wires, insertion tools and other instruments, and other components for performing the procedure.

A more complete understanding of the present invention, and the attendant advantages and features thereof, will be more readily understood by reference to the following detailed description when considered in conjunction with the accompanying drawings, wherein:.

Bilateral pedicle screw fixation has been used to treat degenerative disc disease and other spine pathologies. However, a number of iatrogenic pathologies are associated with pedicle screw fixation. Thus, there is a need for a device allowing a fixation method that reduces the iatrogenic effects of a bilateral pedicle screw construct from a posterior approach while stabilizing the two adjacent vertebral bodies. An inferior pedicle-based intradiscal fixation method may be used in a standalone method or in conjunction with an interbody fixation device. The system may improve access-related morbidity by reducing procedural steps, minimizing soft tissue disruption, and ultimately eliminating violation of the superior facet joint to reduce the risk of adjacent segment disease all while providing improved stability in conjunction with spinal fusion devices. Accordingly, embodiments of the present application are generally directed to devices and systems, for pedicle-based intradiscal fixation of two adjacent vertebrae. The terms device, fixation device, and implant may be used interchangeably herein.

Additional advantages and/or other features of embodiments of the invention will become apparent in view of the following detailed description. It should be apparent to those skilled in the art that the described embodiments provided herein are merely exemplary and illustrative and not limiting.

Referring now to <FIG> and <FIG>, a pedicle-based intradiscal fixation device <NUM> according to one embodiment is shown implanted into two adjacent vertebrae <NUM>, namely, a superior vertebra <NUM> and an inferior vertebra <NUM>. The method of fixation may include, for example, accessing the spine from the posterior and inserting the device <NUM> into the pedicle <NUM> of the inferior vertebra <NUM>. If necessary, bone may be removed from the inferior pedicle <NUM> and/or the vertebral body <NUM> of the inferior vertebra <NUM> in order to facilitate placement of the device <NUM>. The device <NUM> may be further advanced into the vertebral body <NUM> of the inferior vertebra <NUM>. The location and orientation of the device <NUM> may be selected by a surgeon. The device <NUM> may be further configured to be inserted and secured to the vertebral body <NUM> of the adjacent superior vertebra <NUM>. Thus, the device <NUM> may traverse the disc and/or disc space <NUM> between the two vertebrae <NUM>. In this manner, the device <NUM> may be configured to be implanted into both vertebrae <NUM> from a posterior approach, thereby allowing for fusion of the adjacent vertebrae <NUM>. One or more pedicle-based devices <NUM> may be used alone or in conjunction with an interbody fusion device. Although the method is shown with respect to a single inferior pedicle <NUM>, it will be appreciated that the other inferior pedicle may also receive the same or a similar device. It will also be appreciated that the same or similar devices may also be used on adjacent or other levels.

Turning now to <FIG>, the pedicle-based intradiscal fixation implant <NUM> is shown in more detail. The pedicle-based fixation implant <NUM> includes three biocompatible components: a bone fastener <NUM>, a rod <NUM>, and a locking cap <NUM>. The rod <NUM> is configured to be inserted into the bone fastener <NUM> as better explained below. The locking cap <NUM> is arranged to be coupled to the bone fastener <NUM> and to the rod <NUM>. As best seen in <FIG>, the bone fastener <NUM> includes a cannulated path <NUM> for the rod <NUM> to follow. As shown in <FIG>, the rod <NUM> has a straight configuration when the rod <NUM> is first inserted into the bone fastener <NUM>. The cannulated path <NUM> extends along the length of the fastener <NUM> and curves to emerge from the sidewall of the shaft <NUM> of the fastener <NUM>. As shown in <FIG>, when the rod <NUM> is fully deployed through the bone fastener <NUM>, the rod <NUM> curves and protrudes outside the fastener <NUM>. The curved portion of the rod <NUM> is configured to be secured through the inferior vertebral body <NUM>, the disc space <NUM>, and the superior vertebral body <NUM>.

Referring now to <FIG> and <FIG>, the bone fastener <NUM> may be a screw, such as a pedicle screw, that extends from a proximal end with a screw head <NUM> to a distal end with a tip <NUM>. The screw head <NUM> is provided at the proximal end of the bone fastener <NUM> and the tip <NUM> is provided at the distal end of the bone fastener <NUM>. The bone fastener <NUM> extends along a central longitudinal axis A between the proximal and distal ends. The screw head <NUM> may define a drive recess <NUM> (e.g., a female hexagonal recess or other suitable shape) that can be engaged by a screw-driving instrument or other device. The drive recess <NUM> is configured as a through hole. The screw head <NUM> may be enlarged relative to the diameter of the shaft <NUM>, i.e. the external diameter of the screw head is higher than the externa diameter of the shaft. The screw head <NUM> may have any suitable shape. In the embodiment shown, the screw head <NUM> has a curved or spherical surface that is threaded around its periphery and configured to engage with locking cap <NUM>. The threaded portion <NUM> of the screw head <NUM> is configured to threadedly interface with the seat <NUM> of the locking cap <NUM>. It will be appreciated that the screw head <NUM> may be ribbed, roughened, or otherwise configured to mate with the locking cap <NUM>. The screw head has an external lateral surface <NUM> that is externally threaded.

The screw <NUM> has a shaft <NUM> with a plurality of threads <NUM> defined on the sidewall of the shaft <NUM> and configured to engage bone. It will be appreciated that the threads <NUM> may have a number of different features to improve insertion and/or attachment to bone, such as lead(s), thread pitch, thread angle, shaft diameter to thread diameter, overall shaft shape, and the like. It is also contemplated that the threaded shaft <NUM> could be substituted with another suitable bone fastener, such as an anchor, clamp, or the like configured to engage bone. The shaft <NUM> extends along the central longitudinal axis A of the screw <NUM> from the screw head <NUM> to the distal tip <NUM>. The shaft <NUM> terminates distally at tip <NUM>. The distal tip <NUM> may be blunt, pointed, sharpened, or otherwise configured for insertion into bone.

The bone fastener <NUM> is cannulated and defines a hollow body for receiving and guiding the rod <NUM>. The hollow body defines a channel <NUM> configured to slidable receive the rod <NUM>. The cannulated path or channel <NUM> extends from the recess <NUM> in screw head <NUM>, through the shaft <NUM>, and through the sidewall of the shaft <NUM>. The cannulated path <NUM> is in flow communication with the recess <NUM> so as to define a continuous path for the bendable rod <NUM>. The channel <NUM> has a straight portion extending along the central longitudinal axis A from the proximal end to a distance toward the distal tip <NUM>. The straight portion of the channel <NUM> preferably extends internally into the shaft <NUM>, i.e. the sidewall of the shaft <NUM> surrounds the straight portion of the channel <NUM>. As the channel <NUM> nears the distal tip <NUM>, the channel <NUM> has a curved portion extending towards the sidewall of the shaft <NUM> with an exit <NUM> through the outer wall of the shaft <NUM>. At the exit <NUM>, the channel <NUM> emerges on the outer sidewall of the shaft <NUM>. The exit <NUM> is defined on the sidewall of the shaft <NUM> and it is located at a distance from the distal tip <NUM>. In this manner, the channel <NUM> does not extend the entire length of the fastener <NUM> and does not exit the distal tip <NUM>. At the distal tip <NUM> it is provided a threaded portion, the threads of which are not interrupted by the exit <NUM>. The curve of the channel <NUM> may include a minor arc with an acute angle less than <NUM>°. The channel <NUM> may have a smooth inner surface along its length. The smooth curvature may help to guide the rod <NUM> through the fastener <NUM>, such that the rod <NUM> protrudes from the side of the shaft <NUM> and the rod <NUM> curves outside the fastener <NUM>.

The bone fastener <NUM> may be comprised of one or more biocompatible materials. For example, the bone fastener <NUM> may be made from a metal, such as titanium, stainless steel, cobalt chrome, carbon composite, or suitable alloys (such as TAV). These materials may be machined, such as via CNC machining, constructed from additive manufacturing, such as three-dimensional (3D) printing, subtractive manufacturing, or hybrid manufacturing processes. In an exemplary embodiment, the bone fastener <NUM> is constructed via 3D printing with titanium. 3D printing may allow for more liberty with design as compared with traditionally accepted machining and the geometry of the screw can be unique and streamline workflow. Although the materials described herein are exemplified, it will be appreciated that any suitable materials and construction may be selected.

With emphasis on <FIG>, the bendable rod <NUM> includes a proximal end <NUM> configured to mate with the locking cap <NUM> and a distal end <NUM> configured to engage bone. The rod <NUM> may be composed of nitinol or other shape-memory material, which allows the rod <NUM> to bend into a curved state upon deployment. The properties of a shape-memory material may allow for the rod <NUM> to be drawn into the straight configuration from its natural curved state. In its relaxed state, the rod <NUM> may have a curve or bend up to <NUM>°, for example, relative to its straight configuration. The super elastic properties of nitinol allow the low profile configuration shown in <FIG> to be loaded straight into the fastener <NUM>. The nitinol rod <NUM> may be heat treated to shape set a curvature with a defined bend radius, termination angle, and tip geometry suitable for purchasing the superior vertebra <NUM> when fully deployed.

The bendable rod <NUM> may include a proximal portion <NUM> and distal portion <NUM> with different cross-sectional shapes taken perpendicular to the length of the rod <NUM>. Even with different cross-sections, the bendable rod <NUM> may have generally the same diameter along its length. The distal portion <NUM> of the body of the nitinol rod <NUM> may have a polygonal cross-section with planar faces. For example, the distal portion <NUM> of the body may have a generally quadrilateral cross-sectional shape, such as a square. The distal end <NUM> may include a pointed or sharp tip (e.g., pyramidal) configured to pierce bone. In its relaxed state, the distal portion <NUM> of the nitinol rod <NUM> may have a curve or arc with a semi-circle with an angle of about <NUM>° or a curve or minor arc with an acute angle up to <NUM>°. The proximal portion <NUM> of the rod <NUM> may include a generally rounded or cylindrical shape and the proximal end <NUM> may terminate with a conical shape. The proximal portion <NUM> of the rod <NUM> may generally retain the straight configuration even when the distal portion <NUM> bends about the pre-defined bend radius. The proximal end <NUM> is defined at the end of the proximal portion <NUM> and the distal end <NUM> is defined at the end of the distal portion <NUM>. The proximal portion <NUM> may include a threaded portion <NUM> near the proximal end <NUM>, which may be configured to mate with the locking cap <NUM>. The threaded portion <NUM> is preferably located between the proximal portion <NUM> and the proximal end <NUM>.

The locking cap <NUM> may include a generally cylindrical body configured to secure the rod <NUM> in place and/or to the fastener <NUM>. The locking cap <NUM> may define a drive recess <NUM> at its proximal end. The drive recess <NUM> may be a female hexagonal recess or other suitable shape. The drive recess <NUM> may be engaged by a driving instrument or other device to rotate and secure the cap <NUM> to the screw head <NUM> of the fastener <NUM>. The locking cap <NUM> defines a cavity or seat <NUM> opposite to the drive recess <NUM> configured to receive the screw head <NUM> of the bone fastener <NUM>. The seat <NUM> is preferably annular and it is defined by a lateral wall of the locking cap <NUM>. The seat <NUM> is internally threaded and may include a plurality of internal threads <NUM> configured to mate with corresponding threads <NUM> on the outside of the screw head <NUM>, thereby threadedly securing the locking cap <NUM> to the fastener <NUM>. It will be appreciated that the locking cap seat <NUM> may be ribbed, roughened, or otherwise configured to mate with the screw head <NUM>. The locking cap <NUM> may be constructed of the same or similar biocompatible materials as described for the bone fastener <NUM>. The seat <NUM> is preferably blind.

With emphasis on <FIG>, the locking cap <NUM> may engage with the proximal end <NUM> of the rod <NUM>, thereby securing the rod <NUM> in the construct. In the embodiment shown in <FIG>, the locking cap 26A pushes the curved nitinol rod <NUM> slightly forward or distally to compress the rod <NUM> securely. For example, the locking cap seat <NUM> may define a central protrusion <NUM> with a cavity <NUM> for receiving the proximal end <NUM> of the rod <NUM>. The central protrusion <NUM> is preferably defined in a central portion of the locking cap <NUM> and it is internally hollow so as to define the cavity <NUM>. The cavity <NUM> is preferably a through cavity. The central protrusion <NUM> may partially enter into the drive recess <NUM> of the screw head <NUM>. The central protrusion <NUM> and cavity <NUM> may be aligned with the proximal portion <NUM> of the rod <NUM> along the central longitudinal axis A of the implant <NUM>. When the locking cap <NUM> is threadedly secured to the screw head <NUM>, the rod <NUM> seats in cavity <NUM> such that the proximal end <NUM> abuts a bottom surface of the cavity <NUM>. In this manner, the locking cap 26A pushes the rod <NUM> distally, thereby compressing the rod <NUM>. Preferably the seat <NUM> and the cavity <NUM> are coaxial and extends along a longitudinal axis of the locking cap <NUM>.

Alternatively, in the embodiment shown in <FIG>, the locking cap 26B is threadedly engaged with the rod <NUM> to pull the rod <NUM> back slightly in tension to secure it. In this manner, the locking cap 26B can engage threads <NUM>, <NUM> on both the pedicle screw <NUM> and the curved nitinol rod <NUM>, which tightly secures their positioning and interface. In this embodiment, the cavity <NUM> includes a plurality of threads <NUM> configured to interface with corresponding threads <NUM> on the proximal portion <NUM> of the rod <NUM>. The central protrusion <NUM> may fully enter into the drive recess <NUM> of the screw head <NUM> such that the protrusion <NUM> bottoms out inside recess <NUM>. A shoulder <NUM> of the protrusion <NUM> may be configured to abut and engage the top surface of the screw head <NUM>, thereby allowing for the threaded connection to pull the rod <NUM> back proximally, thereby securing the rod <NUM> to the locking cap 26B.

With further emphasis of <FIG>, a method of installing and assembling the implant <NUM> is shown. As shown in <FIG>, the rod <NUM> is straightened and inserted into the channel <NUM> through fastener <NUM>. <FIG> shows an instrument <NUM> coupled to the proximal end <NUM> of the straightened rod <NUM>. The instrument <NUM> may have an inner threaded channel <NUM> configured to temporarily attach the rod <NUM> to the instrument. It will be appreciated that any suitable attachment may be used to secure the rod <NUM> to the insertion instrument <NUM>. Prior to insertion and deployment, the instrumentation <NUM> may capture the proximal threading <NUM> of the curved nitinol rod <NUM> and draw the rod <NUM> back straight and then into the body of the screw <NUM>. The screw <NUM> can be driven forward safely while the deformed nitinol rod <NUM> is flexed straight inside its core. The super elasticity of nitinol allows for the material to be drawn into the straight configuration from its naturally curved state and allows the rod <NUM> to later return to its curved state once fully deployed.

Once the screw <NUM> is inserted to the correct depth and orientation in accordance with pre-operative planning, the deformed nitinol rod <NUM> can be impacted or driven forward through the screw <NUM>. As shown in <FIG>, as the rod <NUM> is moved forward distally, the distal portion <NUM> begins to curve as the rod <NUM> follows the curve in the channel <NUM>. As shown in <FIG>, the rod <NUM> is completely inserted through the bone fastener <NUM> such that the distal portion <NUM> is fully curved (e.g., along the cephalad-caudal plane). Due to nitinol's super elastic properties, the rod <NUM> can be elastically deformed during the procedure and then eventually resume its original shape once in final position. An alternative workflow would proceed by first inserting blank screws <NUM> and then deploying the nitinol rod <NUM> through the full length of the in-position screw <NUM>. Once the rod <NUM> is fully seated through the fastener <NUM>, the instrument <NUM> may be removed from the proximal end <NUM> of the rod <NUM>. As shown in <FIG>, the locking cap <NUM> may then be secured to the screw head <NUM> and/or the end <NUM> of the rod <NUM>, thereby securing their final positions. In this final position the longitudinal axis of the locking cap is coaxial with and preferably corresponds to the longitudinal axis A of the bone fastener <NUM>.

<FIG> show an example of the final construct including a pair of bi-pedicle implants <NUM> deployed through the ipsilateral and contralateral pedicles <NUM> of the inferior vertebra <NUM>. As shown, each implant <NUM> is inserted through the respective pedicle <NUM> of the inferior vertebra <NUM>. The bone fastener <NUM> is positioned through the pedicle <NUM> and into the vertebral body <NUM> of the inferior vertebra <NUM>. The bendable rod <NUM> extends through the fastener <NUM> and the distal portion <NUM> curves upward, thereby allowing for the rod <NUM> to be secured into the inferior vertebral body <NUM>, through the disc space <NUM>, and into the superior vertebral body <NUM>. The implants <NUM> may be used in conjunction with an interbody spacer, such as a lumbar interbody fusion device or an expandable implant, which may include a body with lateral legs, for example. The bendable rod <NUM> may be placed along the inferior pedicle axis and angled accordingly with the axial view to be placed medially to the lateral legs of the interbody while fixating the lower to the upper level. The system may improve access-related morbidity by reducing procedural steps, minimizing soft tissue disruption, and ultimately eliminating violation of the superior facet joint to reduce the risk of adjacent segment disease all while providing improved stability in conjunction with spinal fusion devices.

Turning now to <FIG>, a hybrid implant <NUM> is shown according to another embodiment. Hybrid implant <NUM> is similar to implant <NUM> with a modified tulip head <NUM> attached to the locking cap <NUM> to allow for the connection of a spinal rod thereto. In the event of a revision case, proximal threading <NUM> on the curved nitinol rod <NUM> as well as the screw head <NUM> can be engaged and used to perform adequate adjustments. Revision options may vary, for example, based on the patient anatomy, desired outcome, and surgeon preferences. In one embodiment, the revision procedure may include drawing the nitinol rod <NUM> straight back through the screw <NUM> and out of the patient, leaving the pedicle screw <NUM> in place. This allows for a tulip head (not shown) or other compatible instrumentation and implants to incorporate a standard rod fixation system with the existing pedicle screw <NUM>. In another embodiment, the revision procedure may include drawing the nitinol rod <NUM> into the pedicle screw <NUM> and then removing the entire assembly completely to open the space to entirely different fixation methods. In yet another embodiment, a hybrid case may be implemented in which implant <NUM> remains deployed, but modified tulip head <NUM> is attached to the screw head <NUM> of the pedicle screw <NUM> to allow for spinal rods to be inserted therein.

The hybrid implant <NUM> may include a modified locking cap <NUM> with tulip head <NUM> attached thereto. The tulip head <NUM> may be attached with a rigid arm <NUM>. The arm <NUM> may be a peg or pin that spans between the locking cap <NUM> and the tulip head <NUM>. It will be appreciated that the tulip head <NUM> may be integrally formed with the locking cap <NUM> or otherwise suitably connected thereto. The tulip head <NUM> may be offset laterally to one side of the locking cap <NUM>. The tulip head <NUM> may extend from an upper surface or top to a lower surface or bottom. The tulip head <NUM> may include a body <NUM> and a pair of arms <NUM> that extend upwardly from the body <NUM>. The opposed arms <NUM> may define a channel or rod slot <NUM> therebetween. The rod slot <NUM> may be sized and configured to accept a suitable spinal rod. The spinal rod may be secured in the rod slot <NUM>, for example, via a threaded or non-threaded locking cap (not shown). As shown in <FIG>, the rod slot <NUM> may be aligned substantially parallel to the body of the rod <NUM>, although it will be appreciated that the rod slot <NUM> may be oriented or aligned in any suitable configuration for the desired rod construct. It will further be appreciated that the tulip head <NUM> could be modified to replace the locking cap <NUM> or the arrangement could be otherwise configured to allow for connection to a spinal rod and/or other fixation devices.

Claim 1:
A pedicle-based intradiscal implant (<NUM>) comprising:
- a bendable rod (<NUM>) that extends from a proximal end (<NUM>) having an outer threaded portion (<NUM>) to a distal end (<NUM>) with a sharp tip (<NUM>) configured to engage bone;
- a bone fastener (<NUM>) having a threaded screw head (<NUM>) and a shaft (<NUM>) extending along a central longitudinal axis (A), the bone fastener (<NUM>) defines a channel (<NUM>) for receiving the bendable rod (<NUM>), the channel (<NUM>) has a straight portion extending along the central longitudinal axis (A) and a curved portion with an exit (<NUM>) through a sidewall of the shaft (<NUM>),
characterised in that the implant further comprising
- a locking cap (<NUM>) with an internally threaded seat (<NUM>) for engaging with the screw head (<NUM>) of the bone fastener (<NUM>) and a central protrusion (<NUM>) defining a cavity (<NUM>) for receiving the proximal end (<NUM>) of the bendable rod (<NUM>).