Patent Description:
A common procedure for handling pain associated with intervertebral discs that have become degenerated due to various factors such as trauma or aging is the use of intervertebral fusion devices for fusing one or more adjacent vertebral bodies. Generally, to fuse the adjacent vertebral bodies, the intervertebral disc may first be partially or fully removed. Typically, an intervertebral fusion device may then be inserted between neighboring vertebrae to maintain normal disc spacing and restore spinal stability, thereby facilitating an intervertebral fusion.

There are a number of known conventional fusion devices and methodologies in the art for accomplishing the intervertebral fusion. These include screw and rod arrangements, solid bone implants, and fusion devices which include a cage or other implant mechanism which, typically, is packed with bone and/or bone growth inducing substances. These devices are implanted between adjacent vertebral bodies in order to fuse the vertebral bodies together, alleviating the associated pain.

However, there are drawbacks associated with known conventional fusion devices and methodologies. For example, two important factors in intervertebral fusion may be the anterior (lordotic) angle adjustment and posterior height adjustment. The lordotic angle may be important in restoring sagittal balance while the posterior height may aid in restoring disc height and indirect decompression of the neural foramen. While convention fusion devices may allow for in-situ expansion, they do not allow for the lordotic angle and posterior height to be adjusted in-situ independently of one another. <CIT> or <CIT> represent known prior art.

In the disclosure, a device for inserting and adjusting a therapeutic implant having two rotatable actuators, comprises a body forming a handle portion and having a frame connected to and extending from the handle portion; a tube defining a distal end and an opposed proximal end, having a hollow central bore, supported by the frame to extend away from the body, and having an engagement end at the shaft distal end that is releasably engageable with the implant; first and second stems each having a distal end including a tool end engageable with a rotatable actuator of the implant, having a proximal end rotatable to cause rotation of the distal end to thereby rotate the rotatable actuator of the implant when the tool end is engaged with the implant; the first stem being rotatably and slideably disposed within the hollow central bore of the tube; and the second stem being rotatably and slideably supported by the frame, the tube further including a peripheral external gear at a proximal end, the device further including a rotatable ring having an internal peripheral gear mateable with the peripheral external gear of the tube, the rotatable ring rotatable to cause rotation of the tube to cause the engagement end of the shaft distal end to engage or disengage with the implant.

In variations thereof, the engagement end at the shaft distal end being a threaded surface mateable with threads of the implant; and/or each of the first and second stems includes a spring bearing upon the body and the stem to urge the stem away from the handle portion of the body and into engagement with the implant when the implant is engaged with the tube.

In further variations thereof, each of the first and second stems has a sleeve concentrically surrounding the stem within the handle portion, the spring concentrically surrounding the stem and inside the sleeve, the sleeve and spring retained within the handle portion by a distal and a proximal block; the first and second stems are releasably engageable from the body by moving at least the proximal block; and/or the spring is retained upon the stem by a stem collar at a distal end of the spring and a flange of the sleeve at a proximal end of the spring, the stem, spring, and collar thereby being mutually connected.

In yet further variations, thereof, the proximal block includes two elongated openings each forming an overlapping small bore and large bore, a sleeve each passable through a large bore and not a small bore, the proximal block movable to align each of either the small bores or the large bores with a sleeve; the distal block slideable within the handle portion to bear upon the sleeve of each stem, and to thereby push the respective sleeve, spring, and stem through the large bore and out of the body when the proximal block is moved to align each of the large bores with a sleeve; and/or the distal block is resiliently mounted within the handle portion to align the small bores with the stems in a resting position, and movable by pressing a button formed at an end of the distal block to a release position in which the large bores are aligned with the stems; and/or each of the stems are independently rotatable.

In other variations, a resiliently mounted cam is associated with one of the distal block and the body and a detent associated with the other of the distal block and the body, the cam and detent releaseably engageable as the distal block is moved to define a locked position and a release position; the cam is a ball plunger; the frame includes at least two channels, one of the at least two channels supporting the tube, another of the at least two channels supporting the second stem; the handle portion including two proximal apertures each communicating with a proximal end of a stem; and/or the stems are reversibly removable.

In another embodiment of the disclosure, a device for inserting and adjusting a therapeutic implant having two rotatable actuators, the implant having a threaded connector, where the device comprises a handle; a frame including at least two channels, the frame having a proximal end connected to the handle and a distal end extending away from the handle; a tube defining a distal and an opposed proximal end, having a hollow central bore, supported by the frame to extend away from the body, having threads at the shaft distal end that is releasably engageable with the threaded connector of the implant, and having an external peripheral gear at the proximal end; first and second stems each having a distal end including a tool engagement end engageable with a rotatable actuator of the implant, having a proximal end with a tool engagement rotatable to cause rotation of the distal end to thereby rotate the rotatable actuator of the implant when the tool engagement is engaged with the implant; the first stem being rotatably and slideably disposed within the hollow central bore of the tube, the first stem independently rotatable with respect to the tube; the second stem being rotatably and slideably supported by the frame; and a ring rotatably connected to the handle and including an internal peripheral gear mateable with the external peripheral gear of the tube, the tube thereby rotated by rotation of the ring.

In a variation thereof, each of the first and second stems includes a spring bearing upon the handle and the stem to urge the stem away from the handle portion of the body and into engagement with the implant when the implant is engaged with the tube.

A method (not claimed) of inserting and adjusting a therapeutic implant having two rotatable actuators each operable to change a parameter of the implant, comprises connecting the implant to an inserter having: a body forming a handle portion and having a frame connected to and extending from the handle portion; a tube defining a distal end and an opposed proximal end, having a hollow central bore, supported by the frame to extend away from the body, and having an engagement end at the shaft distal end that is releasably engageable with the implant; first and second stems each having a distal end including a tool end engageable with a rotatable actuator of the implant, having a proximal end rotatable to cause rotation of the distal end to thereby rotate the rotatable actuator of the implant when the tool end is engaged with the implant; the first stem being rotatably and slideably disposed within the hollow central bore of the tube; and the second stem being rotatably and slideably supported by the frame; and rotating the first and second stems to change two parameters of the implant.

In a variation thereof, rotating the first and second stems causes a different change in height of two sides of the implant relative to each other, to thereby define a therapeutic lordotic angle.

A more complete understanding of the present disclosure, 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:.

As required, detailed embodiments are disclosed herein; however, it is to be understood that the disclosed embodiments are merely examples and that the systems and methods (not claimed) described below can be embodied in various forms. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present subject matter in virtually any appropriately detailed structure and function. Further, the terms and phrases used herein are not intended to be limiting, but rather, to provide an understandable description of the concepts.

The terms "a" or "an", as used herein, are defined as one or more than one. The term plurality, as used herein, is defined as two or more than two. The term another, as used herein, is defined as at least a second or more. The terms "including" and "having," as used herein, are defined as comprising (i.e., open language). The term "coupled," as used herein, is defined as "connected," although not necessarily directly, and not necessarily mechanically. Headings are provided for the convenience of the reader and are not to be construed as limiting.

A spinal fusion is typically employed to eliminate pain caused by the motion of degenerated disk material. Upon successful fusion, a fusion device becomes permanently fixed within the intervertebral disc space. With reference to <FIG>, an example of an expandable fusion device, or implant <NUM> that can be inserted and adjusted in accordance with the disclosure is shown between adjacent vertebral bodies <NUM> and <NUM>. Implant <NUM> may be implanted between two adjacent vertebral bodies <NUM> and <NUM> in any section of the spine, including the cervical, thoracic, lumbar, and sacral vertebral sections. More than one expandable fusion device <NUM> may be implanted within the body, for example, between successive or separated vertebrae. As illustrated, implant <NUM> engages the endplates <NUM> and <NUM> of the adjacent vertebral bodies <NUM> and <NUM> and, in the installed position, maintains normal intervertebral disc spacing and restores spinal stability, thereby facilitating an intervertebral fusion. An implant <NUM> can be manufactured from a number of materials including titanium, stainless steel, titanium alloys, non-titanium metallic alloys, polymeric materials, plastics, plastic composites, PEEK, ceramic, and elastic materials.

Two important intervertebral implant parameters for addressing spinal pathologies include lordotic angle and posterior height. The lordotic angle is important, for example, for restoring sagittal balance, while the posterior height aids, at least, in restoring disc height and indirect decompression of the neural foramen. Until the instant disclosure, these parameters could not be adjusted in-situ independently of each other, and particularly without repositioning instruments within the body. In accordance with the disclosure, the medical practitioner can now manipulate both the lordotic angle and height of the implant in situ, without repositioning a tool, to best fit the implant to desired patient anatomy, to thereby more likely obtain a favorable therapeutic result while introducing the least amount of tissue disturbance.

With reference to <FIG>, expansion of the implant <NUM> may be controlled so that the anterior height Ha and the posterior height Hp may be independently controlled. By way of example, the expandable fusion device <NUM> may have independent anterior expansion and posterior expansion mechanisms, each controlled by a separate actuator, shown here with separate tri-lobe and slotted actuator engagements <NUM>, <NUM>, although other engagement types can be employed. By separate control of anterior expansion and posterior expansion, an operator may adjust the expandable fusion device <NUM> to provide a desired amount of posterior height Hp and lordotic angle θ (shown in <FIG>). Alternatively stated, the implant is adjusted along two separate axes. Those of ordinary skill in the art will appreciate that the lordotic angle θ is dependent on the anterior height Ha and posterior height Hp of implant <NUM>. In some embodiments, expansion on the anterior side <NUM> and the posterior side <NUM> may also be performed simultaneously to maintain a lordotic angle θ with only changing the anterior height Ha and the posterior height Hp at the same rate.

The disclosure provides an inserter <NUM> that reversibly engages/disengages from the implant <NUM> (<FIG>), or implant <NUM> (<FIG>) and which can expand and contract the implant with respect to lordotic angle and height, or any two adjustable parameters of the implant. A cannulated, geared, threaded tube <NUM> is actuated by an internal ring gear <NUM> of ring <NUM> (<FIG>) for threading and securing the inserter to the implant. The proximal portion <NUM> of tube <NUM> has a peripheral gear <NUM> which matingly engages with an internal ring gear <NUM> which is concentrically connected to rotatable ring <NUM> that can be knurled as shown to improve grip by a hand of a user. Rotatable ring <NUM> is rotatably mounted to a body <NUM> forming a handle graspable by a user of inserter <NUM>. When rotatable ring <NUM> is rotated, tube <NUM> rotates through engagement of gears <NUM>, <NUM>. The distal end <NUM> of shaft <NUM> (<FIG>) has an external thread <NUM> which is reversibly engaged with mating threads of threaded aperture <NUM> of implant <NUM> (<FIG>), to securely and reversibly fasten inserter <NUM> to implant <NUM>. Tube <NUM> is rotatably supported by a first channel <NUM> which can be formed in one or more sections (each marked as <NUM> in the figures). Alternatives to rotatable ring can include, as examples, directly rotating peripheral gear <NUM>, or other actuator connected to tube <NUM>, for example directly driving an end of tube <NUM> with a tool engagement.

While distal end <NUM> is shown with threads <NUM>, other reversible types of engagement are possible, such as a twist-lock or magnetic connection, for example. One or more tabs <NUM> (<FIG>) or other mating engagement can additionally be provided at a distal end of frame <NUM>, which engage or mate with a corresponding structure on implant <NUM>, to provide alignment and additional stability.

Implants <NUM> and <NUM> are described in detail in <CIT> Herein, implant <NUM> is referenced, however it should be understood that the disclosure can be carried out using any implant with two actuators engageable by inserter <NUM>, including implant <NUM> or other implants of the cited reference, or other known or hereinafter devised implants.

A distal end <NUM> of an elongated stem <NUM> forming a driver is advanced through the bore of tube <NUM> to engage with a mating screw <NUM> (<NUM> in <FIG>) or other actuator of implant <NUM>. A second guide channel <NUM>, which may be formed in one or more sections (each marked as <NUM> in the figures) enables insertion of a second elongated stem <NUM>, which is engageable at a distal end <NUM> with a second mating screw <NUM> (<NUM> in <FIG>) or other actuator of implant <NUM>. Channels <NUM> and <NUM> can be supported by a frame <NUM> that extends from and is unitary with body <NUM>, or is separable as shown in the figures, and is connected to body <NUM>, for example using threaded fasteners <NUM> (<FIG>).

A separable driver or other tool (not shown) can be engaged with a proximal end <NUM> or <NUM> of stem <NUM> or <NUM>, each of which is provided with a tool engagement mateable with the separable driver. In the embodiment shown, and as described further elsewhere herein, stem <NUM> or <NUM> is pushed further into body <NUM> when implant <NUM> is engaged with implant <NUM> (<FIG>). The separable driver tool end may be inserted into body <NUM> to engage stem <NUM> or <NUM> when implant <NUM> is engaged.

Insertion stems <NUM>, <NUM> can be provided with any type of driver engagement at distal end <NUM>, <NUM>, respectively, which mates with implant actuators <NUM>, <NUM>, and any type of driver engagement at proximal ends <NUM>, <NUM>, with mate with the separable driver, such as hex or torx, or the tri-lobe tips shown.

Stems <NUM>, <NUM> are rotatable in either direction to each increase or decrease a parameter of implant <NUM>, such as independently adjusting a height of each side of implant <NUM> to affect both an overall height of the implant as well as a lordotic parameter. When a desired amount of adjustment has been made, either or both of stems <NUM>, <NUM> can be retracted away from the implant, and the tube can be unthreaded from the implant, after which the inserter end may be completely removed from the body.

In accordance with the disclosure, independent control of lordotic angle and posterior height allows the surgeon to better customize the shape and fit of the implant to the patient anatomy. This is unlike known implants where manipulation of both the posterior height and angle is not possible. A tailored fit of both height and angle can help reduce the risk of subsidence and provide an overall better post-surgical result for the patient. The insertion instrument of the disclosure facilitates correct use of variations of implant <NUM> which enable such separate control.

With respect to the embodiment of FIGS. <NUM> et seq. of <CIT> (<FIG> herein, with <FIG> illustrating an alternative implant), and similar implants, in particular, the inserter of the disclosure provides the additional advantage of preventing undesired kyphosis. More particularly, because implant <NUM> can be threaded to the inserter via threads at <NUM> on the posterior side, inserter <NUM> can prohibit greater expansion of the posterior side than the anterior side, ensuring implant <NUM> is not inserted at a kyphotic angle. As the anterior side of implant <NUM> is expanded by rotation of stem <NUM>, the proximal ramp of implant <NUM> is drawn toward the distal side of implant <NUM>. This leave space for the same to occur with the posterior side of implant <NUM>. However, on the posterior side, as the proximal ramp moves closer to the distal side of the implant, the inserter moves with it because they are firmly attached via threads <NUM>. As the posterior side height is brought to the height of the anterior side, the distal end <NUM> of inserter <NUM> is drawn closer to the anterior side of implant <NUM> until it abuts on a surface of the proximal side of implant <NUM>. Accordingly, further expansion of the posterior side is not possible until the anterior side is expanded further.

With reference to <FIG>, in particular, stems <NUM>, <NUM> are slidably mounted within tube inserter <NUM> and channels <NUM>, respectively, to enable engagement and disengagement with implant actuators <NUM>, <NUM>. Stems <NUM>, <NUM> each further slide within a sleeve <NUM> which is disposed within body <NUM>. During use of inserter <NUM>, sleeves <NUM> are prevented from moving within body <NUM> by contact with release assemblies <NUM>, <NUM>, which are positioned on opposite ends of each sleeve <NUM>, as explained further elsewhere herein.

Sleeves <NUM> each house a spring <NUM>. Springs <NUM> are each confined within a sleeve <NUM> by a stop flange <NUM> connected to a proximal end of sleeve <NUM>, and a collar <NUM> disposed about each of stems <NUM>, <NUM>, each stem axially disposed within a sleeve <NUM> and a spring <NUM>. As a result, as stems <NUM>, <NUM> are moved axially by contact with implant <NUM> through a sleeve <NUM>, spring <NUM> is compressed, urging stem <NUM> or <NUM> in a counter direction towards implant <NUM>, for example from the position of <FIG> to the position of <FIG>. Accordingly, distal ends <NUM> and <NUM> are maintained within mating engagement with actuators <NUM>, <NUM> of implant <NUM> as implant <NUM> is manipulated into position and subsequently adjusted. In addition, stop flange <NUM> and collar <NUM> engage the stem with the sleeve <NUM> and spring <NUM>.

In addition to providing a positive engagement between stems <NUM>, <NUM> and implant <NUM>, springs <NUM> enable a given set of stems <NUM>, <NUM> to work with implants of differing configurations. For example, actuators <NUM>, <NUM> may be positioned closer or farther from the threaded engagement formed between external thread <NUM> and threaded aperture <NUM> of implant <NUM>. Springs <NUM> enable stems <NUM>, <NUM> to axially advance as needed to engage actuators <NUM>, <NUM>, while maintaining the same positive engagement regardless of such distance. Springs <NUM> are selected to provide a desired engagement force throughout a range of contact distances anticipated.

The disclosure provides for replacing stems <NUM>, <NUM>, for example to include longer or shorter stems, or stems with different end engagements, and to clean the stems and associated components. With reference in particular to <FIG>, <FIG>, two release assemblies, slide release assembly <NUM> and stop release assembly <NUM>, cooperate to retain stems <NUM>, <NUM>, sleeves <NUM>, and springs <NUM>, within inserter <NUM>.

Stop release assembly <NUM> includes a stop button <NUM> accessible on an external surface of body <NUM>. A blocking surface <NUM> extends from stop button <NUM>, and includes two elongated aperture <NUM> each having an overlapping large bore <NUM> and small bore <NUM>. When stop button <NUM> is pressed, blocking surface <NUM> slides in a slot <NUM> within body <NUM>, moving along an axis transverse to a longitudinal axis of inserter <NUM>. A pin <NUM> passes through body <NUM> and resides within an elongated channel <NUM> within blocking surface <NUM>. In this manner, an extent of movement of blocking surface <NUM> is limited by the dimensions of elongated channel <NUM> and pin <NUM>.

One or more springs <NUM> bear against body <NUM> and blocking surface <NUM> to thereby urge stop button <NUM> and blocking surface <NUM> in an outward, locking direction, whereby stems <NUM>, <NUM> each pass through a small bore <NUM> portion of an elongated aperture <NUM>. Small bore <NUM> is sized so that a sleeve <NUM> cannot pass therethrough. In this manner, stems <NUM>, <NUM> are retained within body <NUM>. Additionally, stem <NUM> or <NUM> cannot pass through spring <NUM> and sleeve <NUM> as they are collectively mutually engaged by collar <NUM> and flange <NUM>, requiring that these components must pass through large bore <NUM> together in order to pass outside of body <NUM>.

To remove stems <NUM>, <NUM>, from a secured position stop button <NUM> is pressed, causing stems <NUM>, <NUM> to pass from the small bores <NUM> into the large bores <NUM>, the latter having a diameter larger than the sleeves <NUM>. Stems <NUM>, <NUM> are now free to emerge from a proximal end <NUM> of body <NUM> (<FIG>). To urge stems <NUM>, <NUM> towards proximal end <NUM>, slide release assembly <NUM> is deployed.

More particularly, slide release assembly <NUM> includes a slide block <NUM> having two apertures <NUM> each sized to allow a stem <NUM> or <NUM> to pass, but sized smaller than sleeve <NUM>. Slide block <NUM> is connected to at least one slide button <NUM> each accessible at a surface of body <NUM>. Slide block <NUM> passes through at least one slot <NUM> opening from an interior of body <NUM> to an exterior of body <NUM>. extends between two slide buttons <NUM>. In the embodiment shown in the figures, there are two slide buttons <NUM> and two slots <NUM> on opposing sides of body <NUM>. As such, slide button <NUM> may be moved to cause slide block <NUM> to bear upon sleeves <NUM> to push sleeves <NUM> together with springs <NUM> and stems <NUM>, <NUM> through large bores <NUM> and out of body <NUM>.

To further control movement of slide block <NUM>, a detent and detent follower can be formed between slide release assembly <NUM> and body <NUM>. As shown in <FIG>, one or more ball plungers <NUM> (a spring loaded roller ball) is mounted to slide block <NUM> or slide buttons <NUM>, and one or mating detents <NUM> (<FIG>) is formed in body <NUM> for each ball plunger <NUM>. Detents <NUM> can be placed at a location corresponding to stem securing or locking position of slide block <NUM> (<FIG>) and a stem releasing position of slide block <NUM> (<FIG>). Slots <NUM> can be dimensioned so that the ball <NUM> of ball plunger <NUM> bears upon a surface throughout a length of travel of ball plunger <NUM>, to guide and further secure slide block <NUM>.

It should be understood that ball plungers <NUM> can alternatively be mounted upon body <NUM>, and detents <NUM> can be positioned upon slide block <NUM> or slide buttons <NUM>. Other detent following cam structures can be provided, for example a resilient tab (not shown) in place of ball plunger <NUM>.

Bushings <NUM> can be provided at a proximal end of each of stems <NUM>, <NUM>, sized to correspond with small bore <NUM> and fabricated of a material, such as a polymer, which promotes smooth passage of stems <NUM>, <NUM> through small bore <NUM>.

In an embodiment, implant <NUM> together with an inserted portion of inserter <NUM> of the disclosure can be configured to be placed into the body through an endoscopic tube or cannula. Inserter <NUM> of the disclosure can be used to implant other types of devices into the body, to be positioned within other joints of the body or elsewhere in the body, particularly where two parameters of the implanted device must be adjusted.

Inserter <NUM> can be fabricated using any biocompatible materials of sufficient strength and durability. If inserter <NUM> is to be reused, it can be made with materials that can withstand the intended method of sterilization. Examples include one or more of titanium, stainless steel, titanium alloys, non-titanium metallic alloys, polymeric materials, plastics, plastic composites, PEEK, ceramic, and elastomeric materials.

The components of the systems and apparatuses may be integrated or separated.

In addition, unless mention was made above to the contrary, it should be noted that all of the accompanying drawings are not to scale. There are many different features to the present disclosure and it is contemplated that these features may be used together or separately. Thus, the disclosure should not be limited to any particular combination of features or to a particular application of the disclosure.

Claim 1:
A device for inserting and adjusting a therapeutic implant (<NUM>, <NUM>) having two rotatable actuators, comprising:
- a body (<NUM>) forming a handle portion and having a frame (<NUM>) connected to and extending from the handle portion;
- a tube (<NUM>) defining a distal end (<NUM>) and an opposed proximal end (<NUM>), having a hollow central bore, supported by the frame (<NUM>) to extend away from the body (<NUM>), and having an engagement end at the tube (<NUM>) distal end (<NUM>) that is releasably engageable with the implant (<NUM>, <NUM>);
- first and second stems (<NUM>, <NUM>) each
having a distal end (<NUM>, <NUM>) including a tool end (<NUM>) engageable respectively with a rotatable actuator of the implant (<NUM>, <NUM>),
having a proximal end rotatable to cause rotation of the distal end (<NUM>, <NUM>) to thereby rotate the rotatable actuator of the implant (<NUM>, <NUM>) when the tool end is engaged with the implant (<NUM>, <NUM>);
- the first stem (<NUM>) being rotatably and slideably disposed within the hollow central bore of the tube (<NUM>); and
- the second stem (<NUM>) being rotatably and slideably supported by the frame (<NUM>),
- wherein the tube (<NUM>) further includes a peripheral external gear (<NUM>) at the proximal end (<NUM>), the device further including a rotatable ring (<NUM>) having an internal peripheral gear (<NUM>) mateable with the peripheral external gear (<NUM>) of the tube (<NUM>), the rotatable ring (<NUM>) rotatable to cause rotation of the tube (<NUM>) to cause the engagement end of the tube distal end (<NUM>) to engage or disengage with the implant (<NUM>, <NUM>).