Bone growth modulating implant device

Abstract

A device may include a moveable body including a first shaft and a first mounting hole configured to receive a first fixation device configured to attach the moveable body to a first bone structure. A device may include a spring. A device may include a housing body including a second shaft and a second mounting hole configured to receive a second fixation device configured to attach the housing body to a second bone structure, wherein the second shaft includes an opening configured to receive the spring and the first shaft of the moveable body.

Description

Patent Application Atty. Docket No. 12558.0013.002 Phoenix Children's Hospital, Inc.BONE GROWTH MODULATING IMPLANT DEVICECROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Patent Application No.63 / 777,424 entitled "TROCHANTERIC DISTRACTION DEVICE" and filed on March 25, 2025, the contents of which are hereby incorporated by reference.FIELD

[0002] The present invention generally relates to medical devices and, more specifically, to an orthopedic implant that may be utilized to modulate growth at a growth plate or physis in a bone.BACKGROUND

[0003] Growth modulating procedures are often utilized in pediatric orthopedics. These procedures rely on the body's own growth potential to correct angular deformities in bones. Growth of bones follow the Heuter Volkmann principal. As such, growth is accelerated responsive to the bone (and, specifically, the bone's physis) being place in tension, while growth is inhibited by the application of a compressive force. Current approaches for modulating bone growth involve placing a fixed device (e.g., staple), or a tension band (eight plate / screw plate construct), or a screw (eccentrically) across a growth plate on one side of the bone, (typically at the convexity of a deformity), so that growth on that side is slowed while the opposite side continues to grow enabling an angular deformity to be corrected with time.SUMMARY{08844420 / 1} -1-Patent Application Atty. Docket No. 12558.0013.002 Phoenix Children's Hospital, Inc.

[0004] This summary section is neither intended to be, nor should be, construed as being representative of the full extent and scope of the present disclosure. Additional benefits, features and embodiments of the present disclosure are set forth in the attached figures and in the description hereinbelow, and as described by the claims. Accordingly, it should be understood that this Summary section may not contain all of the aspects and embodiments claimed herein.

[0005] Additionally, the disclosure herein is not meant to be limiting or restrictive in any manner. Moreover, the present disclosure is intended to provide an understanding to those of ordinary skill in the art of one or more representative embodiments supporting the claims. Thus, it is important that the claims be regarded as having a scope including constructions of various features of the present disclosure insofar as they do not depart from the scope of the methods and apparatuses consistent with the present disclosure (including the originally filed claims). Moreover, the present disclosure is intended to encompass and include obvious improvements and modifications of the present disclosure.

[0006] In some aspects, the techniques described herein relate to a device, including: a moveable body including a first shaft and a first mounting hole configured to receive a first fixation device configured to attach the moveable body to a first bone structure; a spring; and a housing body including a second shaft and a second mounting hole configured to receive a second fixation device configured to attach the housing body to a second bone structure, where the second shaft includes an opening configured to receive the spring and the first shaft of the moveable body.BRIEF DESCRIPTION OF THE DRAWINGS

[0007] The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention.{08844420 / 1} -2-Patent Application Atty. Docket No. 12558.0013.002 Phoenix Children's Hospital, Inc.

[0008] In the drawings:

[0009] FIG. 1 depicts a movable body of the present implantable device.

[0010] FIG. 2 depicts housing body of the present implantable device.

[0011] FIG. 3 is an exploded view of an implantable device.

[0012] FIG. 4 depicts an example installation of implantable device onto femur.

[0013] FIG. 5 depicts a movable body of a second embodiment of the present implantable device.

[0014] FIG. 6 depicts a housing body of the second embodiment of the present implantable device.

[0015] FIG. 7 depicts an exploded view of an implantable device.

[0016] FIGS. 8A-8C depict an embodiment of an implantable device that is configured by an internal spring to bias a moveable body and a housing body towards one another.

[0017] FIG. 9 depicts an alternate embodiment of moveable body of the present implantable device (e.g., movable body, movable body).

[0018] FIG. 10 depicts an implantable device configured in accordance with the present disclosure installed across two adjacent anterior vertebral bodies, with the device including a spring in an extension configuration.

[0019] FIG. 11 depicts an implantable device configured in accordance with the present disclosure installed across two adjacent anterior vertebral bodies, with the device including a spring in an extension configuration.

[0020] FIG. 12 is a detailed view of a fixed peg of the device of FIGS. 8A-C.

[0021] FIG. 13 is a detailed view of a spring hook of the device of FIGS. 8A-C.DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

[0022] The present invention generally relates to medical devices and, more specifically, to an orthopedic implant that may be utilized to modulate growth at a growth plate or physis in a bone.{08844420 / 1} -3-Patent Application Atty. Docket No. 12558.0013.002 Phoenix Children's Hospital, Inc.

[0023] Growth modulating procedures are often used in pediatric orthopedics. These procedures rely upon the body's own growth potential to correct a bone's angular deformity. Growth of bones follows the Heuter Volkmann principal, in which growth is accelerated with tension and inhibited with compression.

[0024] The present disclosure provides an implantable device that may be configured to modulate or augment proximal femoral growth (or growth of other bones). The device may have other indications with slight reconfigurations, as described and contemplated herein.

[0025] In an example use case, the proximal femur in many children with neuromuscular conditions grows "too straight" at the top, exhibiting "coxa valga." This condition is believed to result from a combination of abnormal, unbalanced muscle pull on the bone and decreased weightbearing.

[0026] In an attempt to correct this bone growth deformity and lessen the chance for having a hip dislocation and needing surgery, surgeons have begun placing screws eccentrically across the proximal femoral growth plate. The ability for these implants to change the shape of the proximal femur have been varied. The slow growth at the proximal femur is often blamed for the lack of results as the results depend on inhibiting the growth of a naturally slow growing physis. While eccentrically slowing the growth at a fast -growing physis can be an effective treatment, it follows that inhibiting growth at a slow-growing physis would be less effective.

[0027] As stated above, compression inhibits physeal growth while tension accelerates growth. Accelerating growth is a more effective strategy to modulate growth at slowly growing physes. Current strategies inhibit proximal femoral growth by compressing or placing a screw across the proximal femoral physis at the femoral head. What is also commonly overlooked is that the entire proximal femur has a single growth plate extending from the femoral head (ball) all the way to the trochanter. During normal physical activity - normal weightbearing, standing, moving, children activate their gluteus medius. Children with neuromuscular hip dislocations typically do not do this, which result in these children developing cox valga. The present implantable device is therefore designed to be used with proximal femoral screw epiphysiodesis, and replaces the normal force of the gluteus medius, by placing tension across{08844420 / 1} -4-Patent Application Atty. Docket No. 12558.0013.002 Phoenix Children's Hospital, Inc.the trochanteric physis, essentially "jacking" it up to encourage accelerated lateral growth while also inhibiting growth medially with the epiphyseal screw.

[0028] The present implantable device can be configured into two different modes of operations - distraction mode and compression mode. As such, the present implantable device can be configured to eccentrically accelerate growth across a physis if placed in distraction mode (compression spring internally), or to eccentrically inhibit growth across a physis if placed in compression mode (extension spring internally).

[0029] In these configurations, the implantable device allows for some motion between the device's fixation points (e.g., of particular use in the vertebrae) while continually applying a distractive or compressive force to modulate bone growth. Within the device, a set screw is provided to allow the device to be set into a fixed position during implantation. The set screw can then be released once the device is implanted and fixed in the correct position across the physis.

[0030] In one example use of the present implantable device, the device is fixed to the distal femur using a standard cannulated epiphysiodesis screw, whereas a proximal portion of the device is fixed to the trochanter of the femur using fixed angle locking screws. Depending upon how the device is configured, the device can enhance lateral growth acceleration to medial growth inhibition to more effectively modulate the growth and change the shape of the proximal femur and do so more quickly than relying only on inhibiting already slow proximal femoral growth. A spinal implementation would work similarly, with compression forces being placed across convex disc spaces and distraction forces across concave disc spaces.

[0031] FIG. 1 depicts a movable body 100 of the present implantable device. Movable body 100 includes an opening 102 enabling movable body 100 to be mounted or anchored to a surface using a mounting device (e.g. a screw). Opposite the distal end, movable body 100 includes shaft 104, which is configured to engage with a separate housing body (depicted in FIG. 2).

[0032] FIG. 2 depicts housing body 200 of the present implantable device. Housing body 200 includes openings 202 enabling housing body 200 to be mounted or anchored to a surface using{08844420 / 1} -5-Patent Application Atty. Docket No. 12558.0013.002 Phoenix Children's Hospital, Inc.a mounting device (e.g., screws). Housing body 200 includes shaft 204. Shaft 204 includes an opening 206 configured to receive, first a spring, and second at least a portion of shaft 104 of movable body 100.

[0033] Housing body 200 further includes opening 208. Opening 208 is a threaded opening and is configured to receive a set screw that, as described herein, may be used to lock the implantable device in a particular configuration to facilitate the implantation surgery process. After implantation, the set screw can be loosened or removed to allow operation of the implantable device.

[0034] FIG. 3 is an exploded view of implantable device 300. Device 300 includes movable body 100 and housing body 200. As illustrated, spring 302 is configured to be inserted into opening 206 of housing body 200. Set screw 304 is configured to be threaded into opening 208.

[0035] When assembled (i.e., with spring 302 inserted into opening 206 and shaft 104 of movable body 100 inserted into opening 206), movable body 100 is biased by spring 302 away from housing body 200 allowing implantable device 300, once movable body 100 and housing body 200 are anchored, to apply a distractive force. To further facilitate installation, spring 302 may include a nitinol material so that during implant, spring 302 is biased in a compressed position, but after implant spring 302 relaxes into its normal configuration and operation.

[0036] FIG. 4 depicts an example installation of implantable device 300 onto femur 402. Specifically, implantable device 300 is mounted to femur 402 as a greater femoral trochanter device assembly. Housing body 200 is anchored (e.g., via cannulated screws, not shown) to the greater trochanter of femur 402 and movable body 100 is mounted to the shaft of femur 402 (e.g., via cannulated screw 404). In this configuration, the internal spring (not shown in FIG. 4) operates as a compression spring effectively pushing movable body 100 and housing body 200 apart thereby applying a distractive force to separate (and promote bone growth) in the region of femur 402 across which implantable device 300 is placed. As such, in this configuration, implantable device 300 provides the function of "jacking up the greater trochanter" by pushing upwards (as viewed in FIG. 4).{08844420 / 1} -6-Patent Application Atty. Docket No. 12558.0013.002 Phoenix Children's Hospital, Inc.

[0037] In another embodiment, FIG. 5 depicts a movable body 500 of an implantable device. Movable body 500 includes openings 502 enabling movable body 500 to be mounted or anchored to a surface using mounting devices (e.g. screws). At the opposite end of movable body 500, movable body 500 includes shaft 504, which is configured to engage with a separate housing body (as depicted in FIG. 6).

[0038] FIG. 6 depicts housing body 600 of the present implantable device. Housing body 600 includes openings 602 enabling housing body 600 to be mounted or anchored to a surface using mounting devices (e.g., screws). Opposite the distal end, housing body 600 includes shaft 604. Shaft 604 includes an opening configured to receive, first a spring, and second shaft 504 of movable body 500.

[0039] Housing body 600 includes opening 608 configured to receive a set screw that, as described herein, may be used to lock the implantable device in position to facilitate the implantation surgery process.

[0040] To use the device, a spring is first inserted into opening 608 of housing body 600. Following installation of the spring, shaft 504 of movable body 500 is inserted into opening 608 of housing body 600. A force can then be applied to compress the spring (e.g., by pushing movable body 500 towards housing body 600). With the spring compressed, a set screw can be inserted into opening 608 of housing body 600 to engage with shaft 504 thereby fixing the device in that compressed configuration so that movable body 500 and housing body 600 are unable to move with respect to one another. The device can then be surgically implanted (e.g., by installing appropriate fixation devices through openings 502 of movable body 500 and openings 602 of housing body 600 into desired bone features. Once implanted, the set screw can be removed enabling relative movement of housing body 600 and movable body 500 to enable the spring to create a force that pushes movable body 500 away from housing body 600, enabling the device to operate by applying a distractive force against a desired bone structure.

[0041] FIG. 7 depicts an exploded view of implantable device 700. Device 700 includes moveable body 702 that includes a shaft 704 and opening 706. Opening 706 is configured to{08844420 / 1} -7-Patent Application Atty. Docket No. 12558.0013.002 Phoenix Children's Hospital, Inc.receive a fixation member, such as screw 708, enabling moveable body 702 to be fixed to a bone structure when device 700 is implanted.

[0042] Device 700 includes housing body 710 that include shaft 712 and holes 714. Holes 714 allow housing body 710 to be mounted to a bone structure (e.g., via screws) when device 700 is implanted. Device 700 includes screw 720.

[0043] To assemble device 700, screw 720 is inserted into the shaft 712 of housing body 710. Following screw 720, shaft 704 of moveable body 702 is inserted into shaft 712 of housing body 710. In this configuration, screw 720 operates to provide a force preventing compression of moveable body 702 into housing body 710.

[0044] In other implementations of the present implantable device, the spring member may be configured to prevent expansion of the device (i.e., to oppose the movable body being pulled away from the housing body).

[0045] To illustrate, FIGS. 8A - 8C depict an embodiment of implantable device 800 that is configured by an internal spring 802 to bias moveable body 804 and housing body 806 towards one another (thereby applying a compressive force). FIGS. 8A and 8B show different views of device 800 in which housing body 806 is rendered transparently to show inner features of 800. FIG. 8C is a cross-sectional view of device 800 taken at plane 8C-8C of FIG. 8B vertically (as shown in FIG. 8B) through a centerline of device 800.

[0046] Housing body 806 includes openings 850 or holes through which attachment mechanisms (e.g., screws) can be inserted and secured to a first bone structure. Moveable body 804 includes openings 850 or holes through which attachment mechanisms (e.g., screws) can be inserted and secured to a second bone structure.

[0047] Moveable body 804 includes a spring hook 808 that is fixed to an end of shaft 810 of moveable body 804. In an embodiment, spring hook 808 is removable from moveable body 804. In that case, FIG. 13 is a detailed view of spring hook 808 of device 800 of FIGS. 8A-C. As illustrated, by FIGS. 8A-8C, spring hook 808 is attached to spring 802.

[0048] In a similar manner, a fixed peg 812 is inserted through an opening in housing body 806 and is configured to engage with internal spring 802, thereby acting as a spring retention{08844420 / 1} -8-Patent Application Atty. Docket No. 12558.0013.002 Phoenix Children's Hospital, Inc.peg. In an embodiment, fixed peg 812 is, to some degree, U-shaped, such that fixed peg 812 engages with two separate 813, 815 (see FIG. 8C) holes formed in housing body 806 to provide a secure connection therewith. FIG. 12 is a detailed view of fixed peg 812 of device 800 of FIGS.8A-C.

[0049] In this configuration, spring hook 808 and fixed peg 812 effectively fix spring 802 to moveable body 804 and housing body 806. As such, moveable body 804 and housing body 806pulled apart from one another, spring 802 opposes that action.

[0050] FIG. 9 depicts an alternate embodiment of moveable body 900 of the present implantable device (e.g., movable body 100, movable body 500). In this configuration, moveable body 900 includes a shaft 902 that includes a narrow portion 904 and a distal spherical portion 906. Shaft 902 is connected to a bone plate that includes holes 908 configured to receive fixation devices (e.g., screws). In this configuration, shaft 902 may be coupled with a housing body (e.g., housing body 200 or housing body 600) in the manner described herein. The shape of distal spherical portion 906 allows for an additional 3-degrees of freedom for complex bone shapes. At the same time, narrow portion 904 allows for larger rotational displacement of moveable body 900 with respect to a connected housing body. Holes 908 of the bone plate can feature conical-shaped fine-threaded through-holes for locking screws which will permit the locking screw to maintain perpendicularity relative to the bone plate.

[0051] FIG. 10 depicts an implantable device 1000 configured in accordance with the present disclosure installed across two adjacent anterior vertebral bodies, with the device including a spring in an extension configuration.

[0052] FIG. 11 depicts an implantable device 1100 configured in accordance with the present disclosure installed across two adjacent anterior vertebral bodies, with the device including a spring in an extension configuration.

[0053] In some aspects, the techniques described herein relate to a device, including: a moveable body including a first shaft and a first mounting hole configured to receive a first fixation device configured to attach the moveable body to a first bone structure; a spring; and a housing body including a second shaft and a second mounting hole configured to receive a{08844420 / 1} -9-Patent Application Atty. Docket No. 12558.0013.002 Phoenix Children's Hospital, Inc.second fixation device configured to attach the housing body to a second bone structure, wherein the second shaft includes an opening configured to receive the spring and the first shaft of the moveable body.

[0054] In some aspects, the techniques described herein relate to a device, wherein the spring is configured as a compression to inhibit movement of the moveable body into the housing body.

[0055] In some aspects, the techniques described herein relate to a device, wherein the spring is configured inhibit movement of the moveable body away from the housing body.

[0056] In some aspects, the techniques described herein relate to a device, wherein a first end of the spring is coupled to a distal end of the first shaft.

[0057] In some aspects, the techniques described herein relate to a device, wherein a second end of the spring is coupled to the housing body.

[0058] In some aspects, the techniques described herein relate to a device, further including a spring retention peg inserted into the housing body, wherein the spring retention peg is configured to couple the second end of the spring to the housing body.

[0059] In some aspects, the techniques described herein relate to a device, wherein the spring retention peg is U-shaped and engages with two holes formed in the housing body.

[0060] In some aspects, the techniques described herein relate to a device, wherein the spring includes nitinol.

[0061] In some aspects, the techniques described herein relate to a device, including: a moveable body, including: a first shaft, and a first mounting hole, and a first opening configured to receive a set screw; a spring; a housing body including a second shaft and a second mounting hole, wherein the second shaft includes an opening configured to receive the spring and the first shaft of the moveable body; and a set screw in the first opening, wherein the set screw is configured to, when screwed into the first opening, engage a surface of the moveable body to prevent movement of the moveable body with respect to the housing body.{08844420 / 1} -10-Patent Application Atty. Docket No. 12558.0013.002 Phoenix Children's Hospital, Inc.

[0062] In some aspects, the techniques described herein relate to a device, wherein when the set screw is screwed out of the first opening, the moveable body can move with respect to the housing body.

[0063] In some aspects, the techniques described herein relate to a device, the spring is configured as a compression to inhibit movement of the moveable body into the housing body.

[0064] In some aspects, the techniques described herein relate to a device, wherein the spring is configured inhibit movement of the moveable body away from the housing body.

[0065] In some aspects, the techniques described herein relate to a device, wherein a first end of the spring is coupled to a distal end of the first shaft, and a second end of the spring is coupled to the housing body.

[0066] In some aspects, the techniques described herein relate to a device, further including a spring retention peg inserted into the housing body, wherein the spring retention peg is configured to couple the second end of the spring to the housing body.

[0067] In some aspects, the techniques described herein relate to a device, wherein the spring retention peg is U-shaped and engages with two holes formed in the housing body.

[0068] In some aspects, the techniques described herein relate to a device, wherein the spring includes nitinol.

[0069] In some aspects, the techniques described herein relate to a method, including; a housing body including a first shaft and a first mounting hole, wherein the first shaft includes an opening; inserting a spring into the opening of the housing body; inserting a second shaft of a moveable body into the opening of the housing body, the moveable body including a second mounting hole; inserting a first fixation device through the first mounting hole and into a first bone structure; and inserting a second fixation device through the second mounting hole and into a second bone structure.

[0070] In some aspects, the techniques described herein relate to a method, further including, before inserting the first fixation device and inserting the second fixation device, screwing a set screw into a hole in the housing body to cause the set screw to engage with a{08844420 / 1} -11-Patent Application Atty. Docket No. 12558.0013.002 Phoenix Children's Hospital, Inc.surface of the moveable body to inhibit movement of the moveable body with respect to the housing body.

[0071] In some aspects, the techniques described herein relate to a method, further including: coupling a first end of the spring to a distal end of the first shaft; and coupling a second end of the spring to the housing body.

[0072] In some aspects, the techniques described herein relate to a method, wherein the spring includes nitinol.

[0073] The proximal femur in many children with neuromuscular conditions grows "too straight" at the top having "coxa valga". This is thought to be a combination of abnormal, unbalanced muscle pull on the bone and decreased weightbearing. In an attempt to correct this deformity and lessen the chance for having a hip dislocation and needing a very large surgery, surgeons have begun placing screws eccentrically across the proximal femoral growth plate. The ability for these implants to change the shape of the proximal femur have been varied. The slow growth at the proximal femur is often blamed for the lack of results as the results depend on inhibiting the growth of a naturally slow growing physis. What is commonly overlooked is that the entire proximal femur has a single growth plate extending from the femoral head (ball) all the way to the trochanter.

[0074] During normal physical activity - normal weightbearing, standing, moving, children activate their gluteus medius. Children with neuromuscular hip dislocations do not do this, thus this is probable reason these children develop coxa valga.

[0075] The present implantable device is configured to be used with proximal femoral screw epiphysiodesis, but mechanically re-introduces the missing gluteus medius force, by placing tension across the trochanteric physis encourage accelerated lateral growth while also inhibiting it medially with the epiphyseal screw. This is achieved through an internal "spring" that can be placed in either a distraction or compression mode. The degrees of freedom and silhouette are controlled by the geometry of the male and female components, withcyl i nd rica l / ba 11 having the least restrictions to motion and the rectangular shape having only single planar motion but lower profile. The fixed angle of the proximal screws imparts the{08844420 / 1} -12-Patent Application Atty. Docket No. 12558.0013.002 Phoenix Children's Hospital, Inc.distractive force of the spring to the trochanter, thus providing tension across the lateral growth plate. The force imparted can be controlled by properties of the internal spring. In addition, the device is prepared and "loaded" by compressing the internal spring, then tightening a set screw keep the spring compressed and allowing easy in vivo attachment. Once in place the set screw is removed, deploying the device. Essentially the opposite mode of operation can be achieved placing compression across a physis or vertebral space if that is desired.

[0076] In some aspects, the techniques described herein relate to a device, including: a moveable body including a first shaft and a first mounting hole configured to receive a first fixation device configured to attach the moveable body to a first bone structure; a spring; and a housing body including a second shaft and a second mounting hole configured to receive a second fixation device configured to attach the housing body to a second bone structure, where the second shaft includes an opening configured to receive the spring and the first shaft of the moveable body.

[0077] The preceding detailed description is merely illustrative in nature and is not intended to limit the embodiments of the subject matter or the application and uses of such embodiments.

[0078] As used herein, the word "exemplary" means "serving as an example, instance, or illustration." Any implementation described herein as exemplary is not necessarily to be construed as preferred or advantageous over other implementations. Furthermore, there is no intention to be bound by any expressed or implied theory presented in the preceding technical field, background, or detailed description.

[0079] The connecting lines shown in the various figures contained herein are intended to represent exemplary functional relationships and / or physical couplings between the various elements. It should be noted that many alternative or additional functional relationships or physical connections may be present in an embodiment of the subject matter. In addition, certain terminology may also be used herein for the purpose of reference only, and thus are not{08844420 / 1} -13-Patent Application Atty. Docket No. 12558.0013.002 Phoenix Children's Hospital, Inc.intended to be limiting, and the terms "first", "second" and other such numerical terms referring to structures do not imply a sequence or order unless clearly indicated by the context.

[0080] As used herein, a "node" means any internal or external reference point, connection point, junction, signal line, conductive element, or the like, at which a given signal, logic level, voltage, data pattern, current, or quantity is present. Furthermore, two or more nodes may be realized by one physical element (and two or more signals can be multiplexed, modulated, or otherwise distinguished even though received or output at a common node).

[0081] The foregoing description refers to elements or nodes or features being "connected" or "coupled" together. As used herein, unless expressly stated otherwise, "connected" means that one element is directly joined to (or directly communicates with) another element, and not necessarily mechanically. Likewise, unless expressly stated otherwise, "coupled" means that one element is directly or indirectly joined to (or directly or indirectly communicates with, electrically or otherwise) another element, and not necessarily mechanically. Thus, although the schematic shown in the figures depict one exemplary arrangement of elements, additional intervening elements, devices, features, or components may be present in an embodiment of the depicted subject matter.

[0082] While at least one exemplary embodiment has been presented in the foregoing detailed description, it should be appreciated that a vast number of variations exist. It should also be appreciated that the exemplary embodiment or embodiments described herein are not intended to limit the scope, applicability, or configuration of the claimed subject matter in any way. Rather, the foregoing detailed description will provide those skilled in the art with a convenient road map for implementing the described embodiment or embodiments. It should be understood that various changes can be made in the function and arrangement of elements without departing from the scope defined by the claims, which includes known equivalents and foreseeable equivalents at the time of filing this patent application.{08844420 / 1} -14-

Claims

Patent Application Atty. Docket No. 12558.0013.002 Phoenix Children's Hospital, Inc.CLAIMSWhat is claimed:

1. A device, comprising:a moveable body including a first shaft and a first mounting hole configured to receive a first fixation device configured to attach the moveable body to a first bone structure;a spring; anda housing body including a second shaft and a second mounting hole configured to receive a second fixation device configured to attach the housing body to a second bone structure, wherein the second shaft includes an opening configured to receive the spring and the first shaft of the moveable body.

2. The device of claim 1, wherein the spring is configured as a compression to inhibit movement of the moveable body into the housing body.

3. The device of claim 1, wherein the spring is configured inhibit movement of the moveable body away from the housing body.

4. The device of claim 1, wherein a first end of the spring is coupled to a distal end of the first shaft.

5. The device of claim 4, wherein a second end of the spring is coupled to the housing body.

6. The device of claim 5, further comprising a spring retention peg inserted into the housing body, wherein the spring retention peg is configured to couple the second end of the spring to the housing body.{08844420 / 1} -15-Patent Application Atty. Docket No. 12558.0013.002 Phoenix Children's Hospital, Inc.

7. The device of claim 6, wherein the spring retention peg is U-shaped and engages with two holes formed in the housing body.

8. The device of claim 1, wherein the spring includes nitinol.

9. A device, comprising:a moveable body, including:a first shaft,and a first mounting hole, anda first opening configured to receive a set screw;a spring;a housing body including a second shaft and a second mounting hole, wherein the second shaft includes an opening configured to receive the spring and the first shaft of the moveable body; anda set screw in the first opening, wherein the set screw is configured to, when screwed into the first opening, engage a surface of the moveable body to prevent movement of the moveable body with respect to the housing body.

10. The device of claim 9, wherein when the set screw is screwed out of the first opening, the moveable body can move with respect to the housing body.

11. The device of claim 9, the spring is configured as a compression to inhibit movement of the moveable body into the housing body.

12. The device of claim 9, wherein the spring is configured inhibit movement of the moveable body away from the housing body.{08844420 / 1} -16-Patent Application Atty. Docket No. 12558.0013.002 Phoenix Children's Hospital, Inc.

13. The device of claim 9, wherein a first end of the spring is coupled to a distal end of the first shaft and a second end of the spring is coupled to the housing body.

14. The device of claim 13, further comprising a spring retention peg inserted into the housing body, wherein the spring retention peg is configured to couple the second end of the spring to the housing body.

15. The device of claim 14, wherein the spring retention peg is U-shaped and engages with two holes formed in the housing body.

16. The device of claim 9, wherein the spring includes nitinol.

17. A method, comprising;a housing body including a first shaft and a first mounting hole, wherein the first shaft includes an opening;inserting a spring into the opening of the housing body;inserting a second shaft of a moveable body into the opening of the housing body, the moveable body including a second mounting hole;inserting a first fixation device through the first mounting hole and into a first bone structure;andinserting a second fixation device through the second mounting hole and into a second bone structure.

18. The method of claim 17, further comprising, before inserting the first fixation device and inserting the second fixation device, screwing a set screw into a hole in the housing body to cause the set screw to engage with a surface of the moveable body to inhibit movement of the moveable body with respect to the housing body.{08844420 / 1} -17-Patent Application Atty. Docket No. 12558.0013.002 Phoenix Children's Hospital, Inc.

19. The method of claim 17, further comprising:coupling a first end of the spring to a distal end of the first shaft; andcoupling a second end of the spring to the housing body.

20. The method of claim 17, wherein the spring includes nitinol.{08844420 / 1} -18-

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