Patent Description:
The spine includes a series of joints known as motion segment units. Each unit represents the smallest component of the spine to exhibit a kinematic behavior characteristic of the entire spine. The motion segment unit is capable of flexion, extension, lateral bending, and translation. The components of each motion segment unit include two adjacent vertebrae, the corresponding apophyseal joints, an intervertebral disc, and connecting ligamentous tissue, with each component of the motion segment unit contributing to the mechanical stability of the joint. For example, the intervertebral discs that separate adjacent vertebrae provide stiffness that helps to restrain relative motion of the vertebrae in flexion, extension, axial rotation, and lateral bending.

When the components of a motion segment unit move out of position or become damaged due to trauma, mechanical injury or disease, severe pain and further destabilizing injury to other components of the spine may result. In a patient with degenerative disc disease (DDD), a damaged disc may provide inadequate stiffness, which may result in excessive relative vertebral motion when the spine is under a given load, causing pain and further damage to the disc. Depending upon the severity of the structural changes that occur, treatment may include fusion, discectomy, and/or a laminectomy.

Known treatments for spinal instability can include long-term medical management or surgery. Medical management is generally directed at controlling the symptoms, such as pain reduction, rather than correcting the underlying problem. For some patients, this may require chronic use of pain medications, which may alter the patient's mental state or cause other negative side effects. Surgical treatment typically includes decompression procedures to restore normal disc height, realign the column, and alleviate the pain.

Current surgical treatments often involve the immobilization or fusion of unstable motion segment units, sometimes with the removal of adjacent tissue. One such treatment method involves the rigid fixation of the spine at one or more levels by securing a rigid rod against the spine to prevent motion and thereby enable fusion.

An alternative surgical treatment also stabilizes the spine, but preserves motion instead of promoting fusion. This type of dynamic stabilization typically involves the fixation of a dynamic or spring-like coupler between vertebrae, which would still serve to stabilize and limit motion of the spine, but also allow close-to-normal motion, mimicking the physiological response of a healthy motion segment and providing pain relief, at that level.

There is, nevertheless, a need for a surgical treatment that can address multi-level spine stabilization, and an implantable, modular spine stabilization system that can achieve one or the other type of stabilization at different levels. Rather than having different or separate rod systems to treat multiple levels of the same spine by either rigidly fixing or dynamically stabilizing a single level, what would be desirable is a modular spine stabilization system that could allow either rigid fixation or dynamic stabilization at each level of the same spine to be treated. Further, since this spine stabilization system would span multiple spine levels, it would be further desirable to enable the system to have a curvature that closely matches the curvature of the spine over those multiple levels to be treated, and even more desirable to be able to adjust the curvature of the system to the patient for a customized fit. Accordingly, associated instruments for the assembly and/or implantation of such a modular spine stabilization system are also desirable.

From <CIT> and <CIT> connection elements are known for a spine stabilization system while maintaining a level of flexibility. Furthermore, <CIT> discloses a dual lever surgical rod bending device.

The scope of the invention is defined by independent claim <NUM>. Preferred embodiments are defined by the dependent claims, the description and the Figures. The present disclosure provides an implantable, modular spine stabilization system that allows for multi-level treatment of the spine by providing either rigid fixation or dynamic stabilization at different levels to be treated. This modular spine stabilization system may be configured to span multiple spine levels, and have a curvature that closely matches the curvature of the spine over those multiple levels to be treated. Further, the modular spine stabilization system allows adjustment of the curvature of the overall system such that the system may be adapted for a patient for a customized fit.

Instruments are also provided for the assembly and/or implantation of the modular spine stabilization system. The associated instruments includes instruments for adjusting the curvature of the system to the patient, and for implanting the curved system into the patient. The instruments may be configured for implantation of the system in a minimally invasive surgery.

A kit for modular spine stabilization is provided. The kit comprises an implantable modular spine stabilization system and an associated instrument set for use with the implantable modular spine stabilization system. The spine stabilization system comprises one or more flexible couplers for dynamic stabilization of a spinal segment of a patient's spine. Each coupler has a stem. The system further comprises one or more rigid rods for rigid stabilization of a spinal segment of the patient's spine. Each rigid rod may have an elongated shaft. One or more bone fasteners for attaching the flexible couplers or rigid rods to a patient's spine are also provided in the system.

An instrument set for attaching the spine stabilization system to the patient's spine is also provided with the kit. The instrument set includes a bending instrument for bending a stem of one of the flexible couplers.

In some embodiments, a flexible coupler may be configured to attach to one or more flexible couplers. In other embodiments, a flexible coupler may be configured to attach to a rigid rod.

The stem of the flexible coupler may be curved, or the stem may be straight. Likewise, the shaft of the rigid rod may be curved, or it may be straight. The stem of the flexible coupler may be bendable. The stem and shaft of the flexible coupler and rigid rod, respectively, have threaded ends while the flexible coupler comprises a body having a threaded opening, so that these components can be threadedly connected in series to one another.

The one or more flexible couplers may be provided as a set, and may be differently sized. Likewise, the rigid rods may be provided as a set, and may be differently sized.

The bending instrument comprises a base having a pivoting arm, a pivoting rod holder, and a radius of curvature selection wheel. The pivoting arm has a pusher bar and a pusher head extending from a lower surface therefrom. The pivoting rod holder has a portal for receiving a rod of a medical device to be bent. The bending instrument may be configured such that the lowering of the pivoting arm causes the pusher bar to press against the radius of curvature selection wheel and the pusher head to press against the rod held within the pivoting rod holder.

The pivoting arm can include a handle attachment end. Likewise, the base can also include a handle attachment end. The radius of curvature selection wheel includes one or more detents corresponding to a different radius of curvature. In addition, the pivoting arm can attach to the base at a pivoting hinge.

The pivoting rod holder can include a portal, which may be threaded, for receiving the rod of the medical device. The bending instrument may also include a damper between the pivoting arm and the base. The bending instrument may also include detachable handles for attachment to the base and arm.

As previously mentioned, the bending instrument may be used for bending rods of medical devices. In particular, the bending instrument may be used to bend a stem of the medical device. The medical device may be a flexible coupler such as the one provided in the modular spine stabilization system of the present disclosure.

Other instruments provided with the instrument set of the present disclosure may include a flexible coupler and rod inserter tool. The flexible coupler and rod inserter tool may include an angularly adjustable neck, and be configured for use in a minimally invasive surgery.

Another instrument that may be provided with the instrument set of the present disclosure includes a contouring template. Still another instrument may include a flexible coupler and rigid rod clamping instrument configured to clamp onto a guide rod, which may also be provided with the instrument set of the present disclosure.

The modular spine stabilization system of the present disclosure may include bone fasteners. The bone fastener may comprise a head portion and a shank portion. The head portion may include a cavity for receiving an implantable device. The shank portion may include an elongated shaft extending to a distal tip. The shank portion may have an enlarged head captured within the cavity of the head portion and being defined by a first leading threaded portion adjacent the distal tip. The shank portion may be defined by a first leading threaded portion adjacent the distal tip, a second trailing threaded portion adjacent the head portion, and an intermediate threaded portion extending between the first and second threaded portions. In one exemplary embodiment, the implantable device may comprise a rod.

In one example the first leading threaded portion includes quad lead threads and the second trailing threaded portion may include quad lead threads. In some embodiments, the shank portion may have a generally uniform diameter from the second trailing threaded portion to the end of the intermediate threaded portion, while the first leading threaded portion may have a conical shape. In some embodiments, the first leading threaded portion may include cutting notches. The bone fastener may be cannulated and include cement holes for use with bone cement, in some embodiments.

Additionally, the bone fastener may be color coded for different sizes, and may be configured with a self-tapping distal tip. A locking device for securing the implantable device within the cavity may be provided, in which the locking device is a set screw. Further, the head portion may be attached to an extended head portion at a scored region. This extended head portion may be configured to break away from the head region after use. Additionally, the bone fastener may include an elongate head region for use in a minimally invasive surgery. Once the assembly process is completed, this elongate head region may be snapped off.

The present disclosure may also provide an implantable, modular spine stabilization system. This system may include one or more flexible couplers for dynamic stabilization of a spinal segment of a patient's spine. Each flexible coupler may have a flexible main body and a bendable stem extending therefrom. The system may also include one or more rigid rods for rigid stabilization of a spinal segment of the patient's spine. Each rigid rod may have an elongated shaft.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the disclosure. Additional features of the disclosure will be set forth in part in the description which follows or may be learned by practice of the disclosure.

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate several embodiments of the disclosure and together with the description, serve to explain the principles of the disclosure.

This description and the accompanying drawings illustrate exemplary embodiments and should not be taken as limiting, with the claims defining the scope of the present disclosure. Various mechanical, compositional, structural, and operational changes may be made without departing from the scope of this description and the claims.

In some instances, well-known structures and techniques have not been shown or described in detail so as not to obscure the disclosure. Furthermore, elements and their associated aspects that are described in detail with reference to one embodiment may, whenever practical, be included in other embodiments in which they are not specifically shown or described. For example, if an element is described in detail with reference to one embodiment and is not described with reference to a second embodiment, the element may nevertheless be claimed as included in the second embodiment. Moreover, the depictions herein are for illustrative purposes only and do not necessarily reflect the actual shape, size, or dimensions of the system or illustrated components.

It is noted that, as used in this specification and the appended claims, the singular forms "a," "an," and "the," and any singular use of any word, include plural referents unless expressly and unequivocally limited to one referent. As used herein, the term "include" and its grammatical variants are intended to be non-limiting, such that recitation of items in a list is not to the exclusion of other like items that can be substituted or added to the listed items.

The present disclosure provides an implantable, modular spine stabilization system that allows for multi-level treatment of the spine by providing either rigid fixation or dynamic stabilization at different levels to be treated. This modular spine stabilization system may be configured to span multiple spine levels, and have a curvature that closely matches the curvature of the spine over those multiple levels to be treated. Further, the modular spine stabilization system allows adjustment of the curvature of the overall system such that the system may be adapted for a patient for a customized fit.

Instruments are also provided for the assembly and/or implantation of the modular spine stabilization system. The associated instruments may include instruments for adjusting the curvature of the system to the patient, and for implanting the curved system into the patient. The instruments may be configured for implantation of the system in a minimally invasive surgery.

Turning now to the drawings, <FIG> illustrates an exemplary embodiment of a modular spine stabilization system <NUM> of the present disclosure. The system <NUM> may be configured for multi-level treatment of the spine, with different, individual levels being either rigidly fixed or dynamically stabilized. As shown, a pair of implantable flexible couplers <NUM> may be connected in series, along with an implantable rigid rod <NUM>, to enable multi-level spine stabilization with varied degrees of fixation at individual levels. Bone fasteners <NUM> may be used to secure the couplers <NUM> and the rigid rod <NUM> to the spine. These flexible couplers <NUM> allow limited motion at that level where they are positioned, while the rigid rod <NUM> provides rigid fixation where it is connected.

The modular spine stabilization system <NUM> of the present disclosure may provide two different types of flexible couplers for dynamic stabilization of a spine level: <FIG> shows an exemplary embodiment of a flexible coupler <NUM> having a curved or angled stem 132b, while <FIG> shows an exemplary embodiment of a flexible coupler <NUM> having a straight stem 132a. Each of the stems 132a, 132b may include a threaded end <NUM>, as shown. The flexible coupler <NUM> may be similar to the flexible coupler described in <CIT>, <CIT>, and <CIT>, the contents of all of which are herein incorporated in their entirety by reference. Accordingly, as shown, the flexible coupler <NUM> may comprise a main body <NUM> such as the cylindrical body shown in <FIG>. The flexible coupler body <NUM> may be flexible, compressible, and/or extendable, and formed from a series of coil units 122a. The series of coil units 122a may be connected to one another to form a stepwise series of slots <NUM>. Each slot <NUM> terminates at an opening <NUM> of the flexible body <NUM>. A threaded opening <NUM> may be provided on the flexible body <NUM>, as shown in <FIG>. If so desired, the flexible coupler body <NUM> may comprise an internal distraction-compression stopping mechanism to control or limit the range of motion that can be offered. For example, as shown in <FIG>, a range-of-motion limiting mechanism <NUM> may be provided within the flexible coupler body <NUM>. The internal distraction-compression stopping mechanism <NUM> may be similar to the one described in the aforementioned patents.

In some embodiments, the series of coil units 122A can be formed from a single piece of material such that the units 122A are integrally connected with one another. For example, in one embodiment, the coil units 122A can be etched or cut from a single, tubular piece of material. In other embodiments, one or more coil units 122A can be formed individually and stacked upon one another. The stacked coil units 122A can be connected to one another, for example, by welding or through mechanical connections.

It is contemplated that the flexible coupler body <NUM> may vary in degree of stiffness based on the height, width, distance or angle between two adjacent slots <NUM> and the number of units 122A forming the coupler body <NUM>. Further, one or more units 122A may be formed from different materials so as to vary the mechanical properties of the body <NUM>. In addition, the dimensions of the units 122A, slots <NUM>, and openings <NUM> can be varied within a single body <NUM>.

The modular spine stabilization system <NUM> of the present disclosure may also provide two different types of rigid rods for rigid fixation of a spine level: <FIG> shows a rigid rod <NUM> having a curved or angled shaft 142b, while <FIG> shows a rigid rod <NUM> having a straight shaft 142a. Each of the shafts 142a, 142b may have a tapered, blunt end <NUM> and an opposed, threaded end <NUM>, as shown.

It is understood that each of these flexible couplers <NUM> or rigid fixation rods <NUM> may be provided in various sizes (e.g., length, diameter, angle of stem).

One of the advantages of the modular spine stabilization system <NUM> of the present disclosure is that it is customizable, and allows the user to selective choose which type of flexible coupler <NUM> and/or which type of rigid rod <NUM> to attach in series together, depending on the level of rigidity required at that spinal level, as well as the curvature of the spine to be stabilized. This modularity provides the surgeon with ultimate flexibility in customizing the multi-level spine stabilization system to the patient's needs. For example, <FIG> show the various modular constructs, or configurations, in which this modular spine stabilization system <NUM> may be assembled and utilized:.

<FIG> shows a system configuration, or construct, comprising a flexible coupler <NUM> with a straight stem 132a to be attached to a rigid rod <NUM> having a curved shaft 142b, while <FIG> shows a system configuration, or construct, comprising a flexible coupler <NUM> with a curved stem 132b attached to a rigid rod <NUM> having a curved shaft 142b.

<FIG> shows a system configuration, or construct, comprising a flexible coupler <NUM> with a straight stem 132a attached to a rigid rod <NUM> with a straight shaft 142a, while <FIG> shows a system configuration, or construct, comprising a flexible coupler <NUM> with a curved stem 132b attached to a rigid rod <NUM> having a curved shaft 142b.

<FIG> shows a system configuration, or construct, comprising two flexible couplers <NUM> and a rigid rod <NUM>, all of which have curved stems 132b or a curved shaft 142b, attached in series together. <FIG> shows a system configuration, or construct, comprising two flexible couplers <NUM> and a rigid rod <NUM>, all of which have straight stems 132a or a straight shaft 142a, attached in series together. Of course, it is understood that any one of those dynamic or rigid components could be substituted with one having a straight stem or shaft as well. The various combinations and configurations or constructs shown are merely for illustration purposes only.

A set of instruments <NUM> may be provided for implanting the modular spine stabilization system <NUM>. The instruments may be particularly useful for a minimally invasive surgery (MIS) technique.

<FIG> shows various instruments forming part of the instrument set <NUM> of the present disclosure that can be used to contour (i.e., bend) the stem <NUM> of the flexible coupler <NUM> in order to adapt it to the unique curvature of the patient's spine, as shown in <FIG>. The patient's spine <NUM> has a natural curvature that poses a challenge when connecting components such as the flexible couplers <NUM> of the present disclosure together in series, in order to span and treat multiple levels. By creating a curved stem 132b, the flexible couplers <NUM> are able to connect end-to-end and mimic the curvature of that portion A of the patient's spine <NUM> to be treated, and where the flexible couplers <NUM> are to be implanted. These instruments include a grasper tool <NUM> which cooperates with a clamping instrument <NUM> that can hold onto a guide rod <NUM>. A flexible coupler template <NUM> may be provided which may help the surgeon to approximate the correct angle of the stem <NUM> (i.e., length and angle of curved stem) based on the size of the flexible coupler <NUM>. Using these tools, the surgeon may be able to select the appropriately sized coupler and also determine the correct contour for the stem <NUM> of the flexible coupler <NUM>.

Another instrument that forms part of the instrument set <NUM> of the present disclosure is a bending instrument <NUM> for bending the stem <NUM> of the flexible coupler <NUM>. As shown in <FIG>, in one exemplary embodiment, the bending instrument <NUM> may comprise a base or main body <NUM> configured to attach to detachable handles <NUM>. <FIG> illustrates the base <NUM> without the detachable handles <NUM>, and in greater detail. Within the bending instrument base <NUM> resides a flexible coupler mounting unit <NUM>. The flexible coupler mounting unit <NUM> can be pivoted or raised to a perpendicular, <NUM> degree angle relative to the base <NUM> after lifting arm <NUM>. This allows the straight stem 132a of the flexible coupler <NUM> to be inserted into the mounting unit <NUM>, as will be described in greater detail below. The arm <NUM> attaches to the base <NUM> with a pivoting hinge mechanism <NUM>. Once the arm <NUM> is raised, placing the bending instrument <NUM> in an open position, the flexible coupler mounting unit <NUM> can be pivoted <NUM> degrees upward to receive the straight stem 132a of the flexible coupler <NUM>. The arm <NUM> may include a handle attachment end <NUM> for attachment to a detachable handle <NUM>. Similarly, the base <NUM> may also include a handle attachment knob <NUM> for attachment to a detachable handle <NUM>. Stability bars <NUM> extending from the base <NUM> may also be provided, as shown in <FIG>.

<FIG> illustrate the steps for bending the straight stem 132a using the bending instrument <NUM> of <FIG> and <FIG>. <FIG> shows the bending instrument <NUM> in an open position, i.e., the arm <NUM> is raised upwards, allowing the flexible coupler mounting unit <NUM> to swivel or flip upwards <NUM> degrees on the bending instrument base <NUM>, as shown in <FIG>. This pivoting of the flexible coupler mounting unit <NUM> exposes a portal <NUM> for receiving the straight stem 132a of the flexible coupler <NUM>. Once the portal <NUM> is exposed, the selected flexible coupler <NUM> may be inserted by threading the threaded end <NUM> of the straight stem 132a into the portal <NUM> of the flexible coupler mounting unit <NUM> of the bending instrument <NUM>, as shown in <FIG>.

Next, the desired radius of curvature for the straight stem 132a is selected by dialing the appropriate degree of bending on the radius selection wheel <NUM>. As previously discussed, the desired radius of curvature may be selected using the template <NUM> provided as a selection guide. This radius selection wheel <NUM> includes various angled ramps or detents <NUM> about its circumference. Rotation of the radius selection wheel <NUM> exposes a particular angled ramp or detent <NUM>, as represented in <FIG>, in which the flexible coupler mounting unit <NUM> is pivoted back <NUM> degrees counterclockwise to lay within the base <NUM>.

After the correct radius has been chosen and the radius selection wheel <NUM> rotated to the correct position corresponding to the chosen radius, the arm <NUM> of the bending instrument <NUM> may then be lowered, as shown in <FIG>. In the process of lowering the arm <NUM>, a protruding pusher bar <NUM> extending from the arm <NUM> pushes against the radius selection wheel <NUM> at the selected detent <NUM>, as shown in <FIG>. A pusher head <NUM> extending from the arm <NUM> urges against the straight stem 132a with a corresponding amount of force, thus bending the straight stem 132a of the flexible coupler <NUM>. The pusher head <NUM> may have at a free end a contoured or curved contact surface <NUM> to allow it to effectively push against the cylindrical outer surface of the stem 132a when in contact.

In some embodiments, a damper in the form of a spring <NUM> may be provided, as shown, to facilitate the lowering of the arm <NUM> against the bending instrument base <NUM>. Likewise, the detachable handles <NUM> which are attached to the bending instrument base <NUM> at attachment knob <NUM> as well as the arm <NUM> at attachment end <NUM> also help facilitate the lowering of the arm <NUM> against the base <NUM> to place the instrument <NUM> in a fully closed position. Once the bending instrument <NUM> is in its fully closed position with the flexible coupler <NUM> within the flexible coupler mounting unit <NUM>, the stem <NUM> is bent to the desired radius chosen. <FIG> shows the bending instrument in the open position with the arm <NUM> raised to allow the flexible coupler mounting unit to swivel upwards. The flexible coupler <NUM> with the now bent stem 132b can be removed from the portal <NUM> by unscrewing it from the flexible coupler mounting unit <NUM>, as shown in <FIG> shows the flexible coupler fully removed from the bending instrument <NUM>.

<FIG> illustrates one exemplary embodiment of a bone fastener <NUM> for use with the modular spine stabilization system <NUM> of the present disclosure. The bone fastener <NUM> may comprise a head portion <NUM> shaped like a tulip and a shank portion <NUM>. The head portion <NUM> may include a cavity <NUM> for receiving an implantable device, and an enlarged head <NUM> of the shank portion <NUM> which may sit within the cavity <NUM>. The diameter of the head portion <NUM> may be in the range of about <NUM> to <NUM>. The shank portion <NUM> may include an elongated shaft <NUM> extending from the enlarged head <NUM> to a distal tip <NUM>. The enlarged head <NUM> may include a tool-engaging opening <NUM>, as shown in <FIG>.

The shaft <NUM> of the shank portion <NUM> may be defined by a first leading threaded portion 170a adjacent the distal tip <NUM>, a second trailing threaded portion 170c adjacent the head portion <NUM>, and an intermediate threaded portion 170b extending between the first and second threaded portions.

According to one aspect of the present disclosure, the first leading threaded portion 170a can include quad lead threads, and the second trailing threaded portion 170c can include quad lead threads. Further, the shaft <NUM> may have the same nominal diameter (i.e., outer thread diameter) throughout the entire length of the shaft.

According to another aspect of the present disclosure, the shank portion <NUM> has a generally uniform diameter from the second trailing threaded portion 170c to the end of the intermediate threaded portion 170b. The pitch of the intermediate threaded portion 170b may be between about <NUM> and <NUM>. A conical part <NUM> may be provided in the transition between the second trailing threaded portion 170c and the intermediate threaded portion 170b, while the second trailing threaded portion 170c is generally cylindrical. The intermediate threaded portion 170b may include dual lead threads, in one embodiment.

The first leading threaded portion 170a may have a conical shape in some embodiments. In some embodiments, the first leading threaded portion 170a may include cutting notches <NUM>, as shown in <FIG>. The bone fastener <NUM> may be provided with cement holes <NUM> in some embodiments, as shown. Additionally, the bone fastener <NUM> may be color coded for different sizes, and may be configured with a self-tapping distal tip <NUM>.

As shown, a locking device <NUM> for securing the implantable device within the cavity <NUM> may be provided. This locking device <NUM> may be a set screw, for example. The head portion <NUM> may be an extended tulip head, to accommodate minimally invasive surgery (MIS) instrumentation and techniques during implantation. <FIG> shows a perspective view of the extended tulip head <NUM>, which also includes extended walls <NUM> forming the tulip head extension and being attached at a scored or cutaway portion <NUM> that can be broken off from the tulip head <NUM> after use.

<FIG> illustrates a detailed view of the shaft <NUM>, while <FIG> illustrates a top-down view of the shaft <NUM>, both without the attached tulip head portion <NUM>.

Although the exemplary embodiment described and shown has a first leading threaded portion 170a with quad lead threads, and a second trailing threaded portion 170c with quad lead threads, it is contemplated that other types of lead threads can also be utilized such as dual lead threads, if so desired. For example, any of the threaded portions 170a, 170b, 170c of the shank <NUM> may be provided with double, triple or quad lead threads, although quad lead threads will provide enhanced bone purchase.

<FIG> illustrate an exemplary method (not claimed) of using the bone fasteners <NUM> having the tulip head extension <NUM> attached thereto with the modular spine stabilization system of the present disclosure. <FIG> shows the bone fasteners <NUM> with attached tulip head extensions <NUM> inserted into the patient's spine, while <FIG> shows the system configuration or construct now placed within the bone fasteners <NUM>. These tulip head extensions <NUM> are particularly helpful for MIS techniques. In addition, the tulip head extensions <NUM> can be useful for performing rod reduction procedures. Once the assembly of the stabilization system is completed, and the subcomponents flexible couplers and rigid rods are in their desired arrangement and secured with the bone fasteners <NUM>, the tulip head extensions <NUM> may be broken off at the scored regions <NUM>.

While the assembly of the present system is described as a MIS technique, it is of course understood that the spine stabilization system can be assembled with tradition open surgical techniques as well. To facilitate this assembly in open surgery, bone fasteners <NUM> may be provided having tulip head extensions but of a shorter relative length than for those to be used in a MIS technique.

Turning back to the instrument set <NUM>, it is contemplated that instruments such as a trocar awl, awl, screw dilator, dilator, and screw length ruler may be provided. In addition, a tap, for instance, with a ¼ inch coupling, a tap with a dilator and T-handle with a ratchet, a polyaxial screwdriver, for example, having a straight handle and a T-handle alternative, and a nut driver, for instance, with a ¼ inch coupling, may also be provided within this instrument set <NUM> as well.

In addition, <FIG> show various views of an exemplary embodiment of a flexible coupler and rod inserter tool <NUM> that may be part of the instrument set <NUM> of the present disclosure. The inserter tool <NUM> may include an arm <NUM> extending into a gripping end <NUM> for holding onto a flexible coupler and rigid rod construct, a handle <NUM>, and have a pivotable neck <NUM> connecting the arm <NUM> and handle <NUM>, as shown in <FIG>, which would allow the angular insertion of the implantable components of the modular spine stabilization system <NUM>. The pivotable neck <NUM> is angularly adjustable, and may be locked in position using a tightening nut <NUM>, for example, as shown in <FIG> in the enlarged view. This inserter tool <NUM> may be especially helpful when inserting by a MIS technique. The gripping end <NUM> may include curved walls <NUM> that are configured to firmly grasp the flexible coupler body <NUM>, while finger projections <NUM> may be provided to support and stabilize the elongated shaft <NUM> of the rigid rod <NUM> extending from the flexible coupler and rigid rod construct, as shown in <FIG>. These finger projections <NUM> may be operatively movable from an open position (<FIG>) into a closed position for firmly gripping the flexible coupler body <NUM>, as shown in <FIG>.

In the illustrated embodiment, the flexible coupler <NUM> is threadedly connected to a rigid rod <NUM>, and the construct is grasped by the flexible coupler and rigid rod inserter tool <NUM>. As shown in <FIG>, incisions can be made to enable the inserter tool <NUM> to access the spine <NUM>. The upper-most incision lines IL<NUM> indicate the suggested length and location for the incisions for enabling access of the inserter tool <NUM>. The incisions may be, for example, about <NUM> in length. The second set of shorter incision lines IL<NUM> (e.g., <NUM>) as shown below upper-most incision lines IL<NUM> are for the insertion of the bone fasteners <NUM> at the adjacent levels.

<FIG> illustrate a method (not claimed) of using the inserter tool <NUM> to introduce the flexible coupler and rigid rod construct into the patient, whereby the inserter tool <NUM> is able to hold the flexible coupler and rigid rod construct while positioning it between the walls <NUM> of the extended tulip extensions <NUM>, and seat the construct into the heads <NUM> of the bone screws <NUM>. The angled and adjustable neck <NUM> of the inserter tool <NUM> enables the user to have the necessary angle of approach to perform the steps in a minimally invasive manner.

The modular spine stabilization system <NUM> of the present disclosure may be used for stabilization of both sides of a patient's spine, as illustrated in <FIG> in which a series of flexible coupler to rigid rod constructs may be assembled for implantation along both sides of the spine. In such a case, a crosslink <NUM> may be used to further stabilize the system <NUM>. Accordingly, a measurement tool may be provided with the instrument set <NUM> to determine the appropriate length of the crosslink <NUM> to use.

An exemplary embodiment of a measurement tool <NUM> is shown in <FIG>. The measurement tool <NUM> may include a pair of pivoting arms <NUM> hinged together in a manner similar to scissors or pliers, with one end of the pivoting arms <NUM> interconnected and cooperating to indicate measurement size. As shown, one of the pivoting arms <NUM> may include a laterally extending bar <NUM> having indicia <NUM> representing units of length thereon, while the other pivoting arm <NUM> may have a slot <NUM> for slidingly receiving the laterally extending bar <NUM>. This same pivoting arm <NUM> may further include a window <NUM> through which the user may view the indicia <NUM> on the laterally extending bar <NUM> as it slides across the slot <NUM>. A locking nut <NUM> may be provided to lock the laterally extending bar <NUM> within the slot <NUM> and prevent further movement of the pivoting arms <NUM>.

At the opposite end of the pivoting arms <NUM> are tips <NUM> configured to be placed on the elongated shafts <NUM> of laterally opposed rigid rods <NUM> for measuring the distance between the rigid rods <NUM> located on opposed sides of the spine, as shown in <FIG>. For instance, as shown in <FIG>, the tips <NUM> may have a curved inner surface for placement against the cylindrical surface of the elongate shafts <NUM>, similar to the manner shown in <FIG>. This measured distance can then determine what length crosslink <NUM> would be suited for use at this level.

In another embodiment, the tips <NUM> may be configured for placement within the set screws <NUM> inside the head portions <NUM> of bone screws <NUM>, in order to measure the length between the bone screws <NUM>, as shown in <FIG>. As shown in <FIG>, the tips <NUM> may be shaped and sized to seat within the set screws <NUM>. When used in this manner, the measurement tool <NUM> can also serve to determine the length of a construct, or between bone screws <NUM>, on the same side of the spine.

Claim 1:
A kit for modular spine stabilization, comprising:
an implantable modular spine stabilization system (<NUM>) comprising:
one or more flexible couplers (<NUM>) for dynamic stabilization of a spinal segment of a patient's spine, each flexible coupler (<NUM>) having a flexible main body (<NUM>) at a first end and a stem (132a, 132b) extending therefrom and terminating at a second end;
one or more rigid rods (<NUM>) for rigid stabilization of a spinal segment of the patient's spine, each rigid rod (<NUM>) having an elongated shaft (142a, 142b); and
one or more bone fasteners (<NUM>) for attaching the one or more flexible couplers (<NUM>) or rigid rods (<NUM>) to the patient's spine; and
an instrument set (<NUM>) for use with the implantable modular spine stabilization system (<NUM>),
characterized in that the instrument set (<NUM>) includes a bending instrument (<NUM>) for bending a stem (132a, 132b) of one of the flexible couplers (<NUM>), the bending instrument (<NUM>) comprising a base (<NUM>), a pivoting arm (<NUM>), and a pivoting rod holder (<NUM>), the pivoting arm (<NUM>) having a pusher head (<NUM>) extending from a lower surface of the pivoting arm (<NUM>), and the pivoting rod holder (<NUM>) further having a portal (<NUM>) for receiving the stem (132a, 132b) of the one or more flexible couplers (<NUM>), wherein the bending instrument (<NUM>) has an open position and a fully closed position in which the stem (132a, 132b) of the flexible coupler (<NUM>) is bent, the pivoting rod holder (<NUM>) swiveling upward when the bending instrument (<NUM>) is moved to the open position.