Bone transport implant

Abstract

Various implementations include implants and related methods for moving bone. Particular implementations include an implant (110) for moving a plurality of separate bone segments within a patient's body, the implant comprising: an implantable biocompatible housing (120), a first shuttle (130) coupled to the housing (120) and defining a first set of one or more holes (140) for receiving a bone anchor coupled to a first bone segment within the plurality of bone segments, a second shuttle (150) coupled to the housing (120) and defining a second set of one or more holes (160) for receiving a bone anchor coupled to a second bone segment within the plurality of bone segments, and a drive system (180) at least partially disposed within the housing (120) and configured to translate the first and second shuttles (130, 150) relative to the housing to move the first and second bone segments, respectively.

Description

[Technical Field]

[0001] (Priority Claim) This patent application claims the priority of U.S. Provisional Patent Application No. 63 / 392,201 filed on July 26, 2022. The aforementioned application is incorporated by reference as if fully set forth herein.

[0002] (Field of the Invention) The present disclosure generally relates to biocompatible implants. More particularly, the present disclosure relates to implants for moving bone within a patient's body. [Background Art]

[0003] Implantable bone adjustment systems can beneficially treat various conditions. For example, implantable bone adjustment systems can be used for the purpose of distraction osteogenesis (also known as distraction prosthetics and bone distraction) in the following applications: post-osteosarcoma bone cancer; cosmetic lengthening in short stature or dwarfism / achondroplasia (both legs - femur and / or tibia); lengthening one leg to match the other (congenital, post-traumatic, post-skeletal disorder, artificial knee joint), nonunion, and the like. Furthermore, implantable bone adjustment systems can be used to treat various additional conditions and disorders such as scoliosis or osteoarthritis (e.g., degenerative osteoarthritis).

[0004] Exemplary implantable bone adjustment systems are described in U.S. Patent Application No. 16 / 298,339 filed on March 11, 2019 (now U.S. Patent No. 11,439,449), U.S. Patent Application No. 13 / 370,966 filed on February 14, 2011 (now U.S. Patent No. 8,715,282), and U.S. Patent Application No. 16 / 046,909 filed on July 26, 2018 (now U.S. Patent No. 10,918,425), each of which is incorporated herein by reference in its entirety. [Summary of the Invention]

[0005] The above and other needs are addressed by embodiments of implants and related methods described herein. All examples and features mentioned below can be combined in any technically possible manner.

[0006] Various implementations include implants, associated systems, and methods for moving bone within a patient's body. Specific implementations include implants for moving multiple bone segments within a patient's body.

[0007] In a particular embodiment, an implant for moving multiple distinct bone segments within a patient's body includes: a biocompatible graft housing defining a proximal hole for receiving a bone anchor coupled to a proximal epiphyseal segment and a distal hole for receiving a bone anchor coupled to a distal epiphyseal segment; a first shuttle coupled to the housing and defining a first set of one or more holes for receiving a bone anchor coupled to a first bone segment in the multiple bone segments; a second shuttle coupled to the housing and defining a second set of one or more holes for receiving a bone anchor coupled to a second bone segment in the multiple bone segments; and a drive system at least partially located within the housing and configured to translate the first and second shuttles relative to the housing to move the first and second bone segments, respectively.

[0008] In additional specific embodiments, a method for performing acute shortening and lengthening procedures on multiple bone segments is carried out using implants as described in accordance with embodiments of this disclosure.

[0009] In more specific embodiments, a method for performing a trifocal transport procedure is carried out using an implant as described in accordance with embodiments of this disclosure.

[0010] In additional specific embodiments, a method for moving a patient's long bone is performed using an implant as described in accordance with embodiments of this disclosure. In specific cases, a method for moving at least one of a patient's tibia, humerus, or femur is performed using an implant as described in accordance with embodiments of this disclosure.

[0011] In a particular embodiment, the method includes implanting an implant in a patient; connecting the proximal portion of the implant to a proximal bone portion; connecting the distal portion of the implant to a distal bone portion; connecting a first shuttle of the implant to a first bone segment between the proximal and distal bone portions; and connecting a second shuttle of the implant to a second bone segment between the proximal and distal bone portions.

[0012] In an additional embodiment, the apparatus includes means for moving a first bone segment at a first velocity in a first direction, and means for moving a second shuttle at a second velocity in a second direction.

[0013] The implementation may include one of the following features, or any combination thereof.

[0014] In some cases, the drive system is configured to move the first shuttle and the second shuttle in the same direction at different speeds, or to move them in opposite converging or diverging directions.

[0015] In certain embodiments, the first shuttle includes a first translationable rack mounted within a housing, and the second shuttle includes a second translationable rack mounted within a housing.

[0016] In a particular case, the drive system includes at least one gear, and the implant further includes a first rail coupled to a first shuttle and at least one gear, and a second rail coupled to a second shuttle and at least one gear, wherein movement of the first rail or the second rail translates the movement toward the other of the first rail or the second rail.

[0017] In some embodiments, the drive system directly drives either the first or second shuttle, and indirectly drives the other of the first or second shuttle. In some of these embodiments, a single driver drives both the first and second shuttles.

[0018] In certain implementations, the drive system includes a magnetic driver, which is configured to be driven by an actuator in an external control device from a location outside the patient's body.

[0019] In certain cases, at least one gear of the drive system includes a first gear and a second gear, the first gear and the second gear being coupled by a common shaft. In certain embodiments, with the first gear and the second gear coupled by a common shaft, the first rail and the second rail are positioned on the same side of the coaxial gear.

[0020] In additional specific embodiments, at least one gear of the drive system includes a common gear for driving both the first rail and the second rail, so that the first rail and the second rail are located on either side of the common gear.

[0021] In certain implementations, the first gear and the second gear have separate gear ratios.

[0022] In certain embodiments, the drive system includes at least one of the following: an electric driver configured to be driven by an actuator in an external control device from a location outside the patient's body, or an ultrasonic drive driver configured to be driven by an actuator in an external control device from a location outside the patient's body.

[0023] In certain cases, the electric driver may be driven by a transcutaneous inductive power transfer actuator. In additional cases, the ultrasonic driver may include an ultrasonic piezoelectric driver configured to be driven by an ultrasonic actuator.

[0024] In some implementations, the implant further comprises a lead screw coupled to a drive system and a first shuttle, a first rack coupled to the first shuttle and a second shuttle, a second rack coupled to the second shuttle and a housing, and a rack gear coupled to the second shuttle, the first rack and the second rack.

[0025] In certain aspects, the implant further comprises a pinion gear between the rack gear and the second shuttle for changing the gear ratio of the second shuttle relative to the rack gear. In certain cases, the gear ratio may comprise a 2 / 3 ratio (or 2 / 3 movement speed), a 1 / 2 ratio (or 1 / 2 movement speed), or a 1 / 3 ratio (or 1 / 3 movement speed).

[0026] In some cases, the first rack is fixed to the first shuttle, the second rack is fixed to the housing, and the second shuttle is configured to move relative to the first rack and the second rack.

[0027] In certain implementations, the drive system is configured to drive translation of the lead screw, the first shuttle, and the first rack, wherein translation of the first rack engages the rack gear at a first speed, causing translation of the second shuttle at a second separate speed.

[0028] In certain cases, the drive system comprises a first driver coupled to the first shuttle, and a second driver coupled to the second shuttle, wherein the first shuttle and the second shuttle are axially inserted between the first driver and the second driver.

[0029] In some aspects, each of the first driver and the second driver comprises a magnetic driver configured to be driven by an actuator in at least one external control device from a position external to the patient's body.

[0030] In certain cases, a separate driver may include a separate gear pack for driving a separate shuttle. In some cases, the first and second drivers may be operated simultaneously or concurrently separately by separate controllers.

[0031] In some cases, the first and second drivers are axially separated to mitigate magnetic field interference during operation by an external control device.

[0032] In a particular implementation, the first and second drivers are configured to operate for at least one of the convergence or serial transport of multiple bone segments.

[0033] In some embodiments, the drive system includes a single driver coupled to both the first shuttle and the second shuttle.

[0034] In certain cases, a single driver includes a magnetic driver coupled with two separate gearboxes, the operation of which causes either symmetric translation of the first and second shuttles, or asymmetric translation of the first shuttle relative to the second shuttle. In certain embodiments, the separate gearboxes have separate gear ratios to achieve asymmetric translation.

[0035] In certain embodiments, the housing includes a first sub-housing surrounding a first shuttle and a second sub-housing surrounding a second shuttle.

[0036] In some implementations, the implant further includes an extension rod that extends axially between the first and second sub-housings.

[0037] In certain embodiments, the implant further includes a first lead screw in a first sub-housing coupled to a first portion of the extension rod, and a second lead screw in a second sub-housing coupled to a second portion of the extension rod, and the drive system includes a first driver in a first sub-housing coupled to the first lead screw, and a second driver in a second sub-housing coupled to the second lead screw, wherein the first and second drivers are independently controllable to translate multiple bone segments. In certain cases, the gear ratios in the gearboxes of the first and second implants may be identical to achieve symmetric adjustment, or they may be different to achieve asymmetric adjustment.

[0038] In certain cases, the first lead screw has a first thread orientation, and the second lead screw has a second distinct thread orientation. In certain examples, the thread orientation includes a first thread orientation, such as a left-hand thread orientation, and a second thread orientation, such as a right-hand thread orientation.

[0039] In some embodiments, the first driver and the second driver enable multi-stage extension of multiple bone segments.

[0040] In certain cases, the implant further includes an extension rod within the housing, with a first shuttle located inside the extension rod and a second shuttle driven by the extension rod.

[0041] In certain embodiments, the drive system is coupled to the extension rod to drive the extension rod.

[0042] In some cases, the first shuttle includes a first threaded connection to the extension rod.

[0043] In a particular implementation, the drive system includes a lead screw having a second threaded coupling to the extension rod, wherein the first threaded coupling and the second threaded coupling have separate thread pitches. The separate thread pitches may include, for example, a 2 / 3 pitch, a 1 / 2 pitch, or a 1 / 3 pitch.

[0044] In certain cases, the first threaded joint has a thread pitch that is half the thread pitch of the second threaded joint.

[0045] In some embodiments, the implant further includes a drive system and an extension rod coupled to a first shuttle, and a cable assembly coupled to a drive system and a second shuttle. In certain cases, the drive system includes a gearbox having a connected cable winder.

[0046] In a particular implementation, the cable assembly includes a rewinder coupled to a drive system, a second shuttle, and a cable connected to the rewinder, the operation of the drive system causing the extension rod and the first shuttle to translate, and the winding of the rewinder causing the second shuttle to translate.

[0047] In certain cases, the implant may further include a spring that is coupled to a second shuttle and provides counter-tension to the second shuttle during winding of the winding machine.

[0048] In some embodiments, the implant further includes a lead screw coupled to a drive system, and each of the first shuttle and the second shuttle is directly coupled to the lead screw.

[0049] In certain implementations, the housing includes axially extending slots that allow bone anchors to be directly connected to each of the first and second sets of holes.

[0050] In certain cases, the first and second shuttles are configured to move axially along the slots.

[0051] In some embodiments, the lead screw includes a first threaded coupling to a first shuttle having a first thread pitch, and a second threaded coupling to a second shuttle having a second distinct thread pitch.

[0052] In certain cases, the implant further includes a lead screw coupled to a drive system, at least one band coupled to the lead screw and to a first shuttle and a second shuttle, respectively, and a reel coupled to at least one band. In certain cases, a single drive system can drive both shuttles. In some examples, at least one band includes a polyethylene (PE) band.

[0053] In some implementations, the implant further includes a tether on a lead screw coupled with at least one band.

[0054] In certain cases, the operation of the drive system moves the lead screw within the housing, causing the first shuttle and the second shuttle to move via at least one band.

[0055] In certain embodiments, the housing includes axially extending slots that allow bone anchors to be directly coupled to each of the first and second sets of holes.

[0056] In some implementations, the first and second shuttles are configured to move axially along the slots.

[0057] In certain embodiments, the reel is inserted axially between the first shuttle and the second shuttle.

[0058] In certain cases, the implant further includes a drive system and a lead screw coupled to a first shuttle, and a spring system coupled to a first shuttle and a second shuttle, the spring system configured to provide a translational differential between the first shuttle and the second shuttle when driven by the lead screw.

[0059] In some cases, a portion of the spring system is inserted axially between the first shuttle and the second shuttle.

[0060] In a particular implementation, the spring system includes a first spring and a second spring having distinct spring constants, the first spring being inserted axially between the first shuttle and the second shuttle, and the second spring being inserted axially between the second shuttle and the distal end of the implant.

[0061] In some embodiments, when driven by a drive system and lead screw, a first shuttle translates at a first velocity, and a second shuttle translates at a second separate velocity.

[0062] In certain cases, the second speed is approximately half the first speed.

[0063] In a specific implementation, the spring system self-centers the first and second shuttles relative to the housing in response to the drive system.

[0064] In some cases, the first shuttle includes a drive system having a magnetic driver, a gearbox coupled to the magnetic driver, and a lead screw coupled to the gearbox, the portion of which protrudes axially from the first shuttle.

[0065] In a particular embodiment, the magnetic driver is configured to be driven by an actuator in an external control device from a location outside the patient's body, and the operation of the magnetic driver causes the magnetic driver to be translated axially within the housing.

[0066] In certain implementations, the second shuttle is coupled to the lead screw and configured to translate along with the movement of the lead screw.

[0067] In some cases, the magnetic driver includes a threaded coupler for changing the translational speed of the first shuttle relative to the second shuttle.

[0068] In certain cases, the implant further includes an extension rod that houses a drive system, and the first shuttle is coupled to the drive system.

[0069] In a particular implementation, the drive system includes a magnetic driver and gearbox for driving the lead screw, and the first shuttle includes an anti-rotation mechanism to prevent the first shuttle from rotating while the lead screw is rotating.

[0070] In certain cases, the second shuttle is coupled to the lead screw and configured to translate in proportion to the lead screw.

[0071] In some embodiments, the first shuttle is configured to translate unbalanced with respect to the lead screw.

[0072] In certain cases, the first shuttle and the second shuttle each include a housing, and one or more sets of holes extend at least partially through the housing.

[0073] In a particular implementation, the first and second shuttles are configured to translate relative to the housing to move the first and second bone segments according to a patient adjustment profile for the patient's body. In a particular embodiment, the patient adjustment profile can be customized for the patient, for example, with respect to groove diameter, pitch, and / or grooves per inch / cm.

[0074] In some embodiments, the implant is configured for intramedullary placement in the patient.

[0075] In certain cases, implants are configured to assist in the treatment of leg length inequality or bone defects within a patient's body.

[0076] In certain implementations, the drive system is configured to be powered by a portable power supply.

[0077] In some aspects, the implant is configured for extramedullary placement in the patient.

[0078] In certain cases, the system includes an implant with a biocompatible housing configured for intramedullary placement, and an extramedullary plate.

[0079] In a particular implementation, the method further includes moving a first shuttle at a first velocity in a first direction, and moving a second shuttle at a second velocity in a second direction.

[0080] In some cases, the first and second directions are the same, and the second velocity is greater than the first velocity.

[0081] In certain embodiments, the first and second directions are opposite convergence directions.

[0082] In certain cases, the first and second directions are opposite divergent directions.

[0083] In some embodiments, the movement of the first shuttle and the second shuttle is performed simultaneously.

[0084] In certain implementations, moving the first and second shuttles is done sequentially.

[0085] In certain cases, implanting an implant in a patient includes placing the implant within the medulla.

[0086] In certain embodiments, implanting an implant in a patient includes placing the implant extramedullarily.

[0087] Two or more features described in this disclosure, including those described in this summary section, may be combined to form implementations not specifically described herein.

[0088] The above provides a simplified overview to offer a basic understanding of some aspects of the claimed subject matter. This overview is not a comprehensive overview. It is not intended to identify major or significant elements or to define the scope of the claimed subject matter. Its sole purpose is to present some concepts in a simplified form as a prelude to the more detailed explanations that will follow.

[0089] One or more implementation details are described in the attached drawings and the following description. Other features, purposes, and advantages will become apparent from this description and drawings, as well as from the "Claims." [Brief explanation of the drawing]

[0090] [Figure 1] This is a schematic diagram of a patient's bone segment showing different modes of bone growth under various implementations. [Figure 2] Cross-sectional views of intramedullary implants, implemented in various ways, are shown. [Figure 3] Figure 2 shows schematic system diagrams of the implant with various implementations. [Figure 4] This is a cross-sectional view of an intramedullary implant with various additional implementations. [Figure 5] Figure 4 shows schematic system diagrams of the implant with various implementations. [Figure 6] These are cross-sectional views of intramedullary implants implemented in various ways. [Figure 7] Figure 6 shows schematic system diagrams of the implant with various implementations. [Figure 8] These are cross-sectional views of intramedullary implants implemented in various ways. [Figure 9] Figure 8 shows a schematic system diagram of the implant with various implementations. [Figure 10] This is a cross-sectional view of an intramedullary implant with various additional implementations. [Figure 11] Figure 10 shows schematic system diagrams of the implant with various implementations. [Figure 12]This is a cross-sectional view of an intramedullary implant with various additional implementations. [Figure 13] Figure 12 shows a schematic system diagram of the implant based on a specific implementation. [Figure 14] These are cross-sectional views of intramedullary implants implemented in various ways. [Figure 15] Figure 14 shows schematic system diagrams of the implant with various implementations. [Figure 16] These are cross-sectional views of intramedullary implants implemented in various ways. [Figure 17] Figure 16 shows schematic system diagrams of the implant with various implementations. [Figure 18] These are cross-sectional views of intramedullary implants implemented in various ways. [Figure 19] Figure 18 shows a schematic system diagram of the implant with various additional implementations. [Figure 20] These are cross-sectional views of intramedullary implants implemented in various ways. [Figure 21] Figure 20 shows schematic system diagrams of the implant with various implementations. [Figure 22] These are cross-sectional views of intramedullary implants implemented in various ways. [Figure 23] Figure 22 shows schematic system diagrams of the implant with various implementations. [Figure 24] These are cross-sectional views of intramedullary implants implemented in various ways. [Figure 25] Figure 24 shows schematic system diagrams of the implant with various implementations. [Figure 26] These are cross-sectional views of intramedullary implants implemented in various ways. [Figure 27] Figure 26 shows schematic system diagrams of the implant with various implementations. [Figure 28] A side view of an exemplary bone transport implant in an exemplary initial configuration is shown. [Figure 29] Figure 28 shows a side view of an exemplary bone transport implant in an exemplary end configuration. [Figure 30]A side view of an exemplary bone transport implant in an exemplary initial configuration is shown. [Figure 31] Figure 30 shows a side view of an exemplary bone transport implant in an exemplary screw replacement configuration. [Figure 32] Figure 30 shows a side view of an exemplary bone transport implant in an exemplary end configuration. [Figure 33] A side view of an exemplary bone transport implant in an exemplary initial configuration is shown. [Figure 34] Figure 33 shows a side view of an exemplary bone transport implant in an exemplary screw replacement configuration. [Figure 35] Figure 33 shows a side view of an exemplary bone transport implant in an exemplary end configuration. [Figure 36] A side view of an exemplary bone transport implant having a first slot rotated relative to a second slot is shown. [Figure 37] Figure 36 shows a simplified proximal end view of the bone transport implant. [Figure 38] Exemplary bone transport implants are shown, having slots that are angularly offset from each other and overlap for overlapping zones.

[0091] Please note that the drawings of various implementations are not necessarily to scale. The drawings are intended to illustrate only typical embodiments of this disclosure and should not be considered to limit the scope of implementations. In the drawings, similar numbers represent similar elements across drawings. [Modes for carrying out the invention]

[0092] Despite their numerous applications, conventional bone repositioning systems are limited in the scope and manner of adjustment. In certain cases, patients may benefit from moving multiple distinct bone segments, for example, to accelerate recovery and / or close significant gaps between bone segments. However, conventional methods require multiple tools and multiple adjustments. These conventional methods may be unnecessarily complex, expensive, ineffective, or a combination of these.

[0093] This disclosure provides, at least in part, implants for moving multiple distinct bone segments within a patient's body, and methods for beneficially incorporating such implants for bone movement. These implants enable multi-segment adjustment and can reduce the time and complexity associated with adjustment procedures. The various implementations disclosed can improve patient outcomes compared to conventional implantable adjusters. The disclosed implementations can provide adaptability in adjusting bone placement and can improve one or both of intraoperative and postoperative engagement with devices. The implant can provide an implantable biocompatible housing having a set of shuttles connected to distinct bone segments and a drive system configured to drive the shuttles to enable movement of the bone segments. In various implementations, the drive system is configured to move a first shuttle and a second shuttle in the same direction at different speeds from each other, or in opposite converging or diverging directions. Compared to conventional methods, the multiple bone adjustment implants described according to the various implementations provide an efficient and simplified mechanism for bone adjustment. The implants, as described according to various implementations, can further reduce the patient's health risks compared to conventional methods, for example, by enabling a single implant to perform functions that would otherwise be accomplished by multiple implantable devices (with associated implant procedures) or surgical interventions. Furthermore, challenges exist in providing a mechanism for performing multiple bone adjustments while keeping the device small enough for useful implantation.

[0094] Figure 1 shows two modes of double bone (or multiple bone) transport between epiphyseal segments 10 and 20, with various implementations. In the first mode, bone segments 30 and 40 are both stretched in a common direction between end segment 10 and end segment 20. In certain cases, at least one bone anchor 42 is attached to the bone segments, and in certain cases, two or more bone anchors 42 are attached to each bone segment. In this mode, the first bone growth 50 and the second bone growth 60 are formed by stretching bone segments 30 and 40 by moving the bone segments in the same direction (e.g., the same proximal or distal direction), as shown in the post-transport depiction in the first mode of Figure 1. In the second mode, bone segments 70 and 80 are stretched at convergence (e.g., by moving the bone segments in opposite convergence directions) to form the first bone growth 90 and the second bone growth 100, as shown in the post-transport depiction in the second mode of Figure 1.

[0095] Figure 2 shows a perspective view of implant 110 for moving multiple distinct bone segments within a patient's body, and Figure 3 is a schematic system diagram showing the movement of components within implant 110. In various implementations, implant 110 (and other implants illustrated and described herein) are configured for intramedullary placement in a patient, for example, to assist in the treatment of one or more patient conditions. In certain examples, implant 110 can be used in a method of intramedullary adjustment of a patient's bone. In certain examples, implant 110 (and other implants described herein) are configured to assist in the treatment of leg length inequality and / or bone defects within a patient's body. In other implementations, the multi-segment transport technology described herein can be applied to non-intramedullary uses, such as the correction of scoliosis or other uses.

[0096] In various implementations, the implant 110 includes a biocompatible implantable housing (or "housing") 120. A first shuttle 130 is coupled to the housing 120 and defines a first set of one or more holes 140 for receiving a bone anchor 42 (Figure 1) coupled to a first bone segment (e.g., bone segment 30 in Figure 1). A second shuttle 150 is coupled to the housing 120 and defines a second set of one or more holes 160 for receiving a bone anchor 42 (Figure 1) coupled to a second bone segment (e.g., bone segment 40 in Figure 1).

[0097] The spacing of the holes 140 relative to the distal end 162 of implant 110, the spacing of the holes 160 relative to the proximal end 164 of implant 110, the dimensions of the holes 140 and 160, and other dimensional configurations of the holes 140 and 160 can be adjusted to suit specific patient parameters and / or treatment profiles. In certain configurations, the bone anchor 42 described herein may include bone screws or other bone fixation devices or connectors. In various implementations, the distal end 162 and / or proximal end 164 of implant 110 include additional holes 166 and 168 for receiving the bone anchor 42 and providing additional connection points between implant 110 and bone segments. Examples of dimensional configurations of bone screws and / or holes 140 and 160 are described in U.S. Patent Application No. 16 / 298,339, which is incorporated herein by reference in its entirety.

[0098] The implant 110 may further include a drive system 170, at least partially located within the housing 120, configured to move a first shuttle 130 and a second shuttle 150 relative to the housing 120, thereby moving a first bone segment and a second bone segment, respectively. In particular, the drive system 170 may include a driver 180 coupled with a first adjustment rod 190, the driver 180 being configured to drive the first adjustment rod 190 to enable the translation of the rod 190 relative to the housing 120 (relative to the main axis A). In certain cases, the driver 180 is configured to be actuated by an external control device. In some cases, the external control device includes an external actuator, such as a magnetic controller and / or other wireless controller, for communicating with the driver 180 from a location outside the patient's body. In certain examples, the driver 180 includes at least one of the following: an electric driver configured to be actuated by an actuator in the external control device from a location outside the patient's body, or an ultrasonic drive driver configured to be actuated by an actuator in the external control device from a location outside the patient's body. In some cases, electric drivers may be driven by transcutaneous inductive power transfer actuators. In additional cases, ultrasonic drivers include ultrasonic piezoelectric drivers configured to be driven by ultrasonic actuators. Various drivers are referenced in connection with the implementations described herein. Unless otherwise specified, it should be understood that the illustrated and described drivers (e.g., electric, ultrasonic, etc.) may be used to actuate adjustment rods, lead screws, etc., and to cause rotation and / or translation of such components. Additional details of drivers and driven components are not necessarily included in all descriptions of the implementations. In particular cases, as described herein, the drive system 170 is configured to move the first shuttle and the second shuttles 130, 150 in the same direction at different speeds from each other, or in opposite converging or diverging directions.

[0099] In certain cases, the driver 180 is configured to control the translation of the first adjustment rod 190. In certain implementations, the driver 180 includes a gear module (e.g., having planetary gears) 200 for driving the movement of the first adjustment rod 190. In some examples, the gear module 200 is coupled to a magnetic actuator (e.g., a permanent magnet) 210 rotatably coupled to the gear module 200. However, other drive elements are suitable instead of magnets. For example, in addition to or instead of magnet-based drive, one or more of the drive elements may take the form of a portable electric motor. The portable electric motor may be powered by an external power source (e.g., via a radio frequency link, via an inductive connection, or via another technology). The portable electric motor may be powered by a portable power supply (e.g., a battery that can be charged by an external power source). The portable power supply may be located within the implant (e.g., within its housing) or may be separate from the implant and coupled to the implant via cables. In certain cases, the gear module 200 is attached to a lead screw 220 that drives the translation of the first adjustment rod 190, using radial bearings and / or thrust bearings.

[0100] Referring to the exemplary implant 110 in Figures 2 and 3, the first shuttle 130 may include a first translationable rack 230 mounted within the housing 120 and a second translationable rack 240, also mounted within the housing 120. In certain cases, the translationable racks 230, 240 are configured to translate along separate sections of the housing 120. In certain examples, the driver 180 (or drive system) includes at least one gear 250. In these examples, the implant 110 may further include a first rail 260 coupled to the first shuttle 130 and gear 250, and a second rail 270 coupled to the second shuttle 150 and gear 250. In certain cases, movement of the first rail 260 or the second rail 270 translates the movement of the other of the first rail 260 or the second rail 270. In certain exemplary implementations, driver 180 directly drives either the first shuttle 130 or the second shuttle 150, and indirectly drives the other of the first shuttle 130 or the second shuttle 150. In some of these examples, implant 110 includes a single driver, e.g., driver 180, configured to translate both the first shuttle 130 and the second shuttle 150. In these cases, driver 180 directly drives one of the shuttles and indirectly drives the other shuttle, e.g., via gear 250. In certain examples, such as the particular depictions in Figures 2 and 3, the translationable racks 230, 240 are coupled to a single common gear 250. In such cases, the translationable racks 230, 240 can be located on either side of gear 250.

[0101] In certain additional examples, gear 250 includes a first gear and a second gear coupled by a common shaft 280. In Figures 2 and 3, gear 250 may be coaxially mounted to the common shaft 280, so the first gear 250 of the gear is visible in the cross-sectional view, while the second (or third, fourth, etc.) gear is not visible because it is located behind the visible gear 250. Figures 4 and 5 show another implementation of implant 210 including two separate gears 250A, 250B, these gears are coaxial in certain cases and coupled, for example, by a common shaft 280. In this example, gears 250A, 250B have separate gear ratios (or sizes) that provide differential translation of movement between the translatable racks 230, 240. In such cases, the translationable racks 230 and 240 can be positioned on either side of the gears 250A and 250B, but in certain implementations with separate gears 250A and 250B, as illustrated in Figures 4 and 5, the translationable racks 230 and 240 can be positioned on the same side of the gears 250A and 250B. In certain cases, positioning the translationable racks 230 and 240 on the same side of the gears 250A and 250B can reduce or mitigate the overall thickness of the implant 310. In such cases, implanting and / or removing the implant 310 may be more manageable, and imaging of the implant 310 and / or nearby bone may be improved.

[0102] In additional embodiments, implants 310 are shown in Figures 6 and 7. In these cases, implants 310 include a drive system (e.g., driver 180) and a lead screw 330 coupled to the first shuttle 130. In certain cases, a first rack 350 is coupled to both the first shuttle 130 and the second shuttle 150. A second rack 360 is coupled to the second shuttle 150 and the housing 120. In this implementation, a rack gear 370 is coupled to the second shuttle 150, the first rack 350, and the second rack 360. In certain cases, a pinion gear 380 is positioned between the rack gear 370 and the second shuttle 150 (e.g., adjacent to each other) to change the gear ratio of the second shuttle 150 to the rack gear 370. For example, the gear ratio of the pinion gear 380 may be approximately 2 / 3 ratio (or 2 / 3 travel speed), 1 / 2 ratio (or 1 / 2 travel speed), or 1 / 3 ratio (or 1 / 3 travel speed). In some embodiments, the first rack 350 is coupled to the first shuttle 130 (e.g., fixedly coupled), the second rack 360 is coupled to the housing 120 (e.g., fixedly coupled), and the second shuttle 150 is configured to move relative to the first rack 350 and the second rack 360.

[0103] In this example, the driver 180 is configured to drive the axial translation of the lead screw 330, and then to translate the first shuttle 130 coupled to the lead screw 330 and the first rack 350 coupled to the first shuttle 130. The translation of the first rack 350 engages with the rack gear 370 at a first speed, and then translates the second shuttle 150 (along the second rack 360) at a second separate speed.

[0104] Figures 8 and 9 show additional implementations of the implant 410 in a multi-driver (or multiple drive system) configuration. In these examples, the implant 410 includes a first driver 420 coupled to a first shuttle 130 and a second driver 430 coupled to a second shuttle 150. In various implementations, the first shuttle 130 and the second shuttle 150 are inserted between the first driver 420 and the second driver 430 (for example, axially). In certain cases, the first driver 420 and the second driver 430 each include a magnetic driver 440, which is configured to be driven, for example, from a location outside the patient's body by an actuator in at least one external control device. In certain embodiments, the separate drivers 420, 430 include separate gear packs 450, 460 for driving the separate shuttles 130, 150, for example, via connected lead screws 470, 480, respectively. In such examples, the first driver 420 and the second driver 430 can be operated separately by separate controllers, for example, simultaneously or concurrently. In certain examples, axial separation of the first driver 420 and the second driver 430 can reduce magnetic field interference between the operating drivers 420 and 430, for example, by an external control device. According to certain implementations, the first driver 420 and the second driver 430 are configured to operate for either or both convergence and series transport of multiple bone segments (Figure 1). In some cases, the first driver 420 and the second driver 430 can be operated at separate times, for example, to adjust the position of the first bone segment while maintaining the position of the second bone segment. In additional implementations, gear packs 450 and 460 have separate gear ratios that can provide differential adjustment of the first shuttle 130 relative to the second shuttle 150.

[0105] Figures 10 and 11 show additional implants 510 in various implementations. As shown, the drive system of the implant 510 may include a single driver 520 coupled to both the first shuttle 130 and the second shuttle 150 in the housing 120. In a particular case, the single driver 520 is axially inserted between the first shuttle 130 and the second shuttle 150 and is configured to actuate the translation of both shuttles 130. In some examples, the single driver 520 includes a magnetic driver 530 coupled to two separate gearboxes 540, 550 (and corresponding lead screws 560, 570, respectively). In such a case, the actuation of the magnetic driver 530 causes either symmetric translation of the first shuttle 130 and the second shuttle 150, or asymmetric translation of the first shuttle 130 relative to the second shuttle 150. In a particular example, for example, if asymmetric translation is achieved, the separate gearboxes 540, 550 may have separate gear ratios. The differential gear ratio may include any gear ratio described herein.

[0106] In certain implementations, using a single driver to move both shuttles (e.g., within implant 510) allows for control of the implant with a single control command (e.g., from the ERC), thereby improving ease of use. In certain implementations that utilize multiple drivers (e.g., within implant 410), separate operation may be required in specific cases. However, a multi-driver configuration can allow for more detail in the adjustment regime and / or greater differences between bone segments in the adjustment regime than a single-driver configuration.

[0107] Figures 12 and 13 show the implant 610 with various additional implementations. In certain embodiments, the implant 610 includes a housing 120 having a first sub-housing 620 containing a first shuttle 630 and a second sub-housing 640 containing a second shuttle 650. In these examples, the implant 610 includes an extension rod 660 that extends axially between the first sub-housing 620 and the second sub-housing 640. According to certain implementations, the drive system within the implant 610 further includes a first drive system (driver) 670 and a second drive system (driver) 672. The implant 610 may further include a first lead screw 674 and a second lead screw 676 (inside the housings 620 and 640 in Figure 12). The first lead screw 674 is located within the first sub-housing 620 and is coupled to a first portion 678 of the extension rod 660. A second lead screw 676 is located within a second sub-housing 640 and coupled to a second portion 680 of the extension rod 660. In various implementations, the extension rod 660 includes a set of one or more holes 662 extending through its interior, for example, two or more holes for receiving bone anchors. A first driver 670 in the first sub-housing 620 is coupled to a first lead screw 674, and a second driver 672 in the second sub-housing 640 is coupled to a second lead screw 676. In certain cases, the first driver 670 and the second driver 672 can be controlled separately to translate multiple bone segments within the patient. According to a particular example, the gearboxes in the first and second drivers 670 and 672 may have the same gear ratio to achieve symmetric adjustment of the first shuttle 630 and the second shuttle 650. In an additional example, the gearboxes in the first and second drivers 670, 672 may have separate gear ratios to achieve asymmetric adjustment of the first shuttle 630 relative to the second shuttle 650. In a particular example, the first lead screw 674 has a first thread orientation (e.g., left-hand thread orientation), and the second lead screw 676 has a second separate thread orientation (e.g., right-hand thread orientation).In certain cases, the first driver 670 and the second driver 672 enable multi-stage extension of multiple bone segments, for example, by activating the first driver and then the second driver (or both drivers).

[0108] Figures 14 and 15 show implants 710 with additional implementations. In these examples, the implant 710 may include an extension rod 720 within a housing 730. In such examples, a first shuttle 740 is located inside the extension rod 720, and a second shuttle 750 is configured to be driven by the extension rod 720. In certain embodiments, a drive system (driver) 760 is coupled to the extension rod 720 and configured to drive the extension rod 720, as with other drive systems shown herein. In some cases, as shown in Figure 15, the first shuttle 740 includes a first threaded coupling 770 with the extension rod 720. As further shown in Figures 14 and 15, the driver 760 includes a lead screw 780 having a second threaded coupling 790 to the extension rod 720. In various implementations, the first threaded coupling 770 and the second threaded coupling 790 have separate thread pitches. In one example, the first threaded joint 770 has a thread pitch that is half the thread pitch of the second threaded joint 790. In an additional example, the first threaded joint 770 has a thread pitch that is two-thirds or one-third the thread pitch of the second threaded joint 790. In various implementations, the internal shuttle 740 allows a single extension rod (and a single driver 760) to control the adjustment of both shuttles 740, 750 (and consequently multiple bone segments). In a particular case, the differential thread pitch between the joints 770, 790 allows a single driver 760 to control the differential adjustment of the first shuttle 740 compared to the second shuttle 750, for example, enabling the differential adjustment of multiple bone segments.

[0109] Figures 16 and 17 show the implant 810 with various additional implementations. In some embodiments, the implant 810 includes a driver 830 and a stretching rod 820 coupled to a first shuttle 840. The implant 810 may further include a cable assembly 845 coupled to the driver 830 and a second shuttle 850. In certain cases, the driver 830 includes a gearbox 860 having a connected cable winder 870. In certain implementations, the winder 870 is coupled to the driver 830, and the cable 890 is connected to the second shuttle 850 and the winder 870. The cable 890 can be connected to the second shuttle 850 and the winder 870 by pinning, fastening, bolting, or other means. During use, the operation of the driver 830 translates the stretching rod 820 and the first shuttle 840, and also causes the winder 870 to wind in order to translate the second shuttle 850. In an additional example, implant 810 further includes a spring 892 coupled to a second shuttle 850 to provide reverse tension to the second shuttle 850 during winding by the winding machine 880. In various implementations, the spring 892 is fixed to the housing 893 on the side 894 opposite to the side connected to the second shuttle 850. In such cases, the spring constants of the spring 892 and the winding machine 880 can be selected or otherwise calibrated to control the amount of reverse tension on the second shuttle 850 during winding by the winding machine 880.

[0110] Figures 18 and 19 show the implant 910 in various implementations. As shown, the implant 910 may include a lead screw 920 coupled to a drive system (driver) 930. In these implementations, two shuttles, including a first shuttle 940 and a second shuttle 950, are each directly coupled to the lead screw 920. In specific cases, the lead screw 920 is either passed through slots in the shuttles 940 and 950, or directly coupled to the shuttles 940 and 950 via fasteners, pins, clips, screw connections, etc. In various implementations, the housing 960 for the implant 910 includes an axially extending slot 970 that allows bone anchors (Figure 1) to be directly coupled to each of the first and second sets of holes 140 and 160. In these cases, the holes 140 and 160 are directly accessible to the bone anchors via the slot 970, for example, without passing through the housing 960. In some examples, the slot 970 extends along one side of the housing 960, and the holes 140, 160 allow the bone anchor to pass through the interior without passing through the housing 960. In various implementations, the first shuttle 940 and the second shuttle 950 are configured to move axially along the slot 970 as, for example, the lead screw 920 translates relative to the housing 960. In certain implementations, the lead screw 920 includes at least two separate threaded connectors that allow for differential adjustment of the bone segments. For example, the lead screw 920 may include a first threaded connector 980 coupled to the first shuttle 940 and a second threaded connector 990 coupled to the second shuttle 950. In various implementations, the first threaded connector 980 has a first thread pitch, and the second threaded connector has a second separate thread pitch. In various implementations, the difference in thread pitch between the first threaded coupling and the second threaded couplings 980, 990 may be as in other examples described herein, for example, 2 / 3, 1 / 2, 1 / 3, etc. In a particular case, the different thread pitches between the couplings 980, 990 allow for differential axial adjustment of the first shuttle 940 relative to the second shuttle 950 when driven by the lead screw 920.

[0111] Figures 20 and 21 show the implant 1010 in various implementations. In these cases, the implant 1010 includes a housing 1015 having a lead screw 1020 coupled to a drive system (driver) 1030, and one or more bands 1040 coupled to the lead screw 1020 and to each of the first shuttle 1050 and the second shuttle 1060. In some examples, the bands 1040 include polyethylene bands. The implant 1010 further includes a reel 1070 coupled to the bands 1040 for winding and unwinding the bands 1040 during use, for example. In additional implementations, a tether 1080 is coupled to the lead screw 1020 and the bands 1040, for example, to connect the bands 1040 to the lead screw 1020. In certain examples, the tether 1080 is attached to the end of the lead screw 1020. In certain examples, a single driver, e.g., driver 1030, can drive both the first shuttle 1050 and the second shuttle 1060. That is, the operation of driver 1030 moves the lead screw 1020 within the housing 1015, causing the movement of the first shuttle 1050 and the second shuttle 1060, respectively (via band 1040). In certain examples, the first shuttle 1050 is directly coupled to the lead screw 1020, and the second shuttle 1060 is indirectly coupled to the lead screw via band 1040 and tether 1080. In certain embodiments, the housing 1015 includes, for example, an axially extending slot 1090 that allows for direct coupling of bone anchors (Figure 1) to the holes 140, 160 in the first and second sets within each of the shuttles 1050, 1060, without passing through the housing 1015. In some implementations, the first shuttle 1050 and the second shuttle 1060 are configured to move axially along the slot 1090, similar to the implant 910 in Figures 18 and 19. In certain embodiments, a reel 1070 is inserted axially between the first shuttle 1050 and the second shuttle 1060. In these cases, the first shuttle 1050 and the second shuttle 1060 are configured to translate within separate slots in the housing 1015, for example, the slots include axial ends or stoppers to restrict the translation of the shuttles 1050 and 1060.

[0112] Figures 22 and 23 show the implant 1110 with various additional implementations. As shown, the implant 1110 includes a housing 1115 which may include a lead screw 1120 coupled to a first shuttle 1140 (for example, with various implementations herein) and a drive system 1130 for driving the lead screw 1120. A spring system 1150 is coupled to the first shuttle 1140 and the second shuttle 1160. In various implementations, the spring system 1150 is configured to provide translational differential between the first shuttle 1140 and the second shuttle 1160 when the shuttles 1140 and 1160 are driven by the lead screw 1120. In one exemplary configuration shown in Figures 22 and 23, the spring system 1150 includes a first portion 1152 inserted axially between the first shuttle 1140 and the second shuttle 1160. In certain cases, the spring system 1150 includes a first spring 1170 coupled to the distal end 1180 of the first shuttle 1140 and the proximal end 1190 of the second shuttle 1160. In some of these cases, the spring system 1150 may include a second spring 1172 coupled to the distal end 1182 of the second shuttle 1160. In these examples, the first spring 1170 is inserted axially between the first shuttle 1140 and the second shuttle 1160. In certain implementations, the first spring 1170 has a first spring constant, and the second spring 1172 has a second distinct spring constant. In certain examples, as described herein, a first spring 1170 is inserted axially between a first shuttle 1140 and a second shuttle 1160, and a second spring 1172 is inserted axially between the second shuttle 1160 and the distal end 164 of the implant 1110. In certain cases, the second spring 1172 is fixed at its distal end 1192 to a portion of the housing 1115 (e.g., fastened, pinned, integrally formed, etc.). In certain cases, when driven by the drive system 1130 and lead screw 1120, the first shuttle 1140 translates at a first velocity, and the second shuttle 1160 translates at a second separate velocity. In certain examples, the second velocity is approximately half the first velocity.In a further specific example, the spring system 1150 is configured to center (or "self-center") the first shuttle 1140 and the second shuttle 1160 relative to the housing 1115 in response to being driven by the drive system 1130.

[0113] Figures 24 and 25 show implants 1210 with additional implementations. In these cases, implant 1210 has a first shuttle 1220 coupled to a housing 1240. In these implementations, the first shuttle 1220 includes a drive system 1250 having a magnetic driver 1260 and a gearbox 1270 coupled to the driver 1260. In certain implementations, a stem 1280 protrudes axially from the magnetic driver 1260 and is at least partially surrounded by a radial bearing 1282, for example, to maintain the axial alignment of the magnetic driver 1260 and reduce friction during movement. In some cases, as described herein, the magnetic driver 1260 is driven by an actuator in an external control device and configured, for example, to axially translate the driver 1260 within the housing 1240. In some cases, the magnetic driver 1260 includes a threaded coupler 1290 for controlling the translational speed of the first shuttle 1220 relative to the housing 1240. In certain cases, implant 1210 may include a second self-driven shuttle (not shown) similar to the first shuttle 1220 and facing the first shuttle 1220 within housing 1240 (e.g., similar to Figures 8 and 9). In these implementations, the second self-driven shuttle may include a drive system (similar to drive system 1250) having a magnetic driver (similar to magnetic driver 1260) with an axially extending stem, and a gearbox (similar to gearbox 1270) coupled to the driver. In various implementations, the magnetic driver in the second self-driven shuttle is driven by an actuator in an external control device to, for example, axially translate the second self-driven shuttle within housing 1240. In certain cases, the magnetic driver in the second self-driven shuttle includes a second threaded coupler for controlling the speed of translation of the second self-driven shuttle relative to housing 1240. In some cases, the threaded coupler has a differential thread configuration (e.g., different thread pitches and / or orientations) to provide differential translational speeds for the first shuttle 1220 relative to the second (self-driven) shuttle.In various implementations, the shuttle is configured to translate axially along a set of internal guides (or rails). The movement of the first and second shuttles (and the corresponding extension rods) may be restricted axially by at least one fastener, such as a bulkhead or wall, which is inserted axially, as in the configurations shown in Figures 8 and 9.

[0114] Figures 26 and 27 show implant 1310 with additional implementations. In these cases, implant 1310 includes a drive system 1320 housed within an extension rod 1330. In certain examples, the entire drive system 1320 is housed within the extension rod 1330, but this is not necessarily the case in all implementations. The drive system 1320 may include a magnetic driver 1332 and a gearbox 1340 for driving the lead screw 1350. In these cases, the first shuttle 1360 is coupled with the drive system 1320 and the lead screw 1350. During operation, the magnetic driver 1330 can be actuated, for example, via a remote actuator and / or onboard actuator to actuate the gearbox 1340 and then drive the lead screw 1350. In certain cases, the first shuttle 1360 includes an anti-rotation mechanism, such as a set of complementary tabs / slots or a flat surface (flat portion), to prevent the first shuttle 1360 from rotating while the lead screw 1350 is rotating. In some such cases, the first shuttle 1360 is configured to translate unbalanced with respect to the lead screw 1350 relative to the housing 1390. For example, the anti-rotation mechanism can prevent the first shuttle 1360 from rotating while the lead screw 1350 is rotating (at least a portion of it). In such cases, the anti-rotation mechanism can extend axially along a portion of the length of the housing 1390 (axial length along axis A). In certain cases, the implant 1310 may include a second shuttle (not shown) similar to the first shuttle 1360 and facing the first shuttle 1360 within the housing 1390 (for example, similar to Figures 8 and 9). In these implementations, the second shuttle may include a drive system having a magnetic driver (similar to drive system 1320) and a gearbox either housed within the second extension rod (similar to extension rod 1330). In various implementations, the magnetic driver in the second shuttle is configured to be driven by an actuator in an external control device, for example, to drive the second lead screw (and corresponding second extension rod) in the second shuttle axially within the housing 1390. In specific cases, the first and second shuttles include separate magnetic drivers.In some cases, the second shuttle may include an anti-rotation mechanism, such as complementary tabs and slots, flat surfaces (flat sections), in the set to prevent the second shuttle from rotating while the second lead screw is rotating (similar to the first shuttle 1360). The movement of the first and second shuttles (and the corresponding extension rods) may be restricted axially by at least one fastener, such as an axially inserted fastener, such as a bulkhead or wall, as in the configurations shown in Figures 8 and 9.

[0115] Conventional bone transport implants can use a screw-replacement procedure to allow bone transport to be carried by a single shuttle across the implant's bridge, which divides the full transport length across two separate slots. To utilize the full length of the two combined slots, there are two locking screw options on the implant that require a screw-replacement procedure to provide continuous transport across the full length of the slots. The procedure is as follows: the first screw reaches the end of the first slot, and the second screw option is accessible within the second slot on the other side of the supporting bridge and positioned before the first screw is removed. Transport continues uninterrupted until the first screw is removed, clearing the supporting bridge, and the second screw reaches the end of the second slot. This screw-replacement procedure may allow the implant to have a bridge that reinforces the implant, but requires the patient to undergo a new surgery for the screw-replacement.

[0116] An exemplary advantage of transporting multiple bone segments is that the intramedullary implant can contain multiple bone transport slots separated by one or more bridges of material without requiring a screw replacement procedure for the full range of bone transport. By dividing the entire slot through which the bone transport shuttle passes into multiple slots, the resulting support bridges between the slots increase the strength of the implant.

[0117] Figures 28 and 29 show the first exemplary bone transport implant 2800 in its initial and final configurations, respectively. The initial configuration may be a configuration in which the implant 2800 is pre-transplant, intra-transplant, or post-transplant prior to significant bone transport. The final configuration may be a configuration of the implant 2800 after sufficient operation has occurred and significant bone transport has taken place (e.g., after sufficient bone transport has occurred and the bone transport treatment plan for the implant recipient has been met). The bone transport implant 2800 includes a first longitudinal slot 2810 in which a first bone transport shuttle 2812 is positioned, and a second longitudinal slot 2820 in which a second bone transport shuttle 2822 is positioned.

[0118] The material bridge 2830 separates the first longitudinal slot 2810 from the second longitudinal slot 2820. The bridge 2830 can be any material or structure separating the slots 2810, 2820. In one example, the bridge 2830 may be the housing material for the implant 2800. In some examples, the bridge 2830 is positioned so that one or more of the shuttles 2812, 2822 can pass under the bridge 2380. However, bone screws or other structures linking each shuttle 2812, 2822 to their respective bone segments may prevent the movement of the connected shuttles 2812, 2822 under the bridge 2380. However, in this configuration of the implant 2800, a screw replacement procedure is not required to cover bone movement along the entire length of the slot, so the bridge 2830 in this example may be configured so that the shuttles 2812, 2822 cannot pass underneath.

[0119] In the illustrated configuration, the bone transport shuttles 2812 and 2822 are configured to begin near the opposite end of implant 2800 and converge via the action of the implant (as described in more detail elsewhere in this specification, for example). As shown in Figure 29, the shuttles 2812 and 2822 can converge near bridge 2830. In other words, each bone segment carried by shuttles 2812 and 2822 can come into contact with bridge 2830 (for example, portions of the bone segment come into contact with bridge 2830 in overlapping positions).

[0120] In this example, by having at least two bone segments that move toward the bridge 2830, the implant 2800 may include a bridge 2830 that increases strength without the recipient of the implant having to undergo a screw replacement procedure to obtain full range of transport.

[0121] Nevertheless, implants with multiple shuttles benefit from supporting the screw replacement procedure, as shown in Figures 30–32.

[0122] Figure 30 shows a second exemplary bone transport implant 3000 in an exemplary initial configuration (e.g., the initially implanted configuration). Here, implant 3000 is similar to implant 2800, except that shuttles 2812, 2822 are configured to start in the same slot 2810 and move in the same direction (e.g., using any such technique described elsewhere herein). A second slot 2820 starts without a shuttle in it (e.g., implanted). The second shuttle 2822 includes at least a proximal anchor 2824 and a distal anchor 2826 for bonding to a bone segment. The anchors 2824, 2826 may be, for example, screw holes into which screws can be fastened. The proximal anchor 2824 may bond to a bone segment during implantation, while the distal anchor 2826 may not be used for starting (e.g., not connected to a bone segment).

[0123] Figure 31 shows a second simplified bone transport implant 3000 in an exemplary screw-replacement configuration. The illustrated configuration can be achieved after sufficient operation of the implant 3000 (e.g., using any technique described herein). For example, operation can be performed to position the second shuttle 2822 such that the bridge 2830 is between the proximal anchor 2824 and the distal anchor 2826. Using the screw-replacement procedure described above or elsewhere, the distal anchor 2826 can be coupled to the bone segment (e.g., using a screw), and the proximal anchor 2824 can be separated from the bone segment. Thus, following the screw-replacement procedure, the shuttle 2822 can advance past the bridge without the bone anchors blocking the shuttle's movement. Meanwhile, operation can be performed to advance the first shuttle 2812 approximately halfway along the first slot 2810. Continuing the operation, the implant 3000 can reach the configuration shown in Figure 32.

[0124] Figure 32 shows a second simplified bone transport implant 3000 in an exemplary end configuration. As shown, the first shuttle and the second shuttles 2812, 2822 reach their respective distal ends in the first and second slots 2810, 2820, respectively.

[0125] In the configuration illustrated in Figures 30 to 32, the first shuttle 2812 moves only within the first slot 2812 and does not cross the bridge 2830. The second shuttle 2822 is the only shuttle that crosses the bridge 2830. However, the implant does not have to be configured in this way. For example, Figures 33 to 35 show implant 3300 in which all shuttles are configured to start and end in different slots.

[0126] Figure 33 shows implant 3300 in an exemplary initial configuration (e.g., the configuration of implant 3300 when implanted). Here, implant 3300 includes a first slot 3310, a second slot 3320, a third slot 3330, and a fourth slot 3340. A first bridge 3350 is located between the first slot 3310 and the second slot 3320. A second bridge 3360 is located between the second slot 3320 and the third slot 3330. A third bridge 3370 is located between the third slot 3330 and the fourth slot 3340. A first shuttle 2812, having a proximal anchor 2814 and a distal anchor 2816, is located in the first slot 3310. A first bone segment can be connected to the first shuttle 2812 via the proximal anchor 2814. The distal anchor 2816 is not connected to the first bone segment. A second shuttle 2822, having a proximal anchor 2824 and a distal anchor 2826, is positioned in the fourth slot 3340. The second bone segment can be connected to the second shuttle 2822 via the distal anchor 2826. The proximal anchor 2824 is not connected to the second bone segment. Thus, the first slot 3310 (e.g., the nearest slot) and the fourth slot 3340 (e.g., the most distal slot) contain the respective shuttles 2812 and 2822, while the second slot 3320 and the third slot 3330 lack shuttles. The implant 3000 can be configured (e.g., using any of the techniques described herein) so that the shuttles 2812 and 2822 can move toward each other, eventually passing under their respective bridges and reaching the two intermediate slots 3320 and 3330.

[0127] Figure 34 shows a third exemplary bone transport implant 3300 in an exemplary screw-replacement configuration, in which at least a portion of the first shuttle 2812 overlaps with the first bridge 3350 (for example, both are intersected by the same plane perpendicular to the length of implant 3300), and at least a portion of the second shuttle 2822 overlaps with the third bridge 3370. The illustrated configuration can be achieved after sufficient operation of implant 3300. For example, operation can cause the first shuttle 2812 to be positioned so that bridge 3350 is located between proximal anchor 2814 and distal anchor 2816. Operation can further cause the second shuttle 2822 to be positioned so that bridge 3370 is located between proximal anchor 2824 and distal anchor 2826.

[0128] Using the screw replacement procedure described above or elsewhere, the distal anchor 2816 of the first shuttle 2812 can be coupled (e.g., by screw) to the first bone segment, and the proximal anchor 2814 of the first shuttle 2812 can be separated from the bone segment. During the screw replacement procedure, the proximal anchor 2824 of the second shuttle 2822 can be coupled (e.g., by screw) to the second bone segment, and the distal anchor 2826 of the second shuttle 2822 can be separated from the second bone segment. Thus, following the screw replacement procedure, both shuttles 2812 and 2822 can advance past their respective bridges 3350 and 3370 without being blocked (e.g., by the screws connecting the bone segments to the anchors hitting the bridge). Continuing the operation, the implant 3000 can reach the configuration shown in Figure 35.

[0129] Figure 35 shows a third simplified bone transport implant 3300 in an exemplary end configuration. As shown, the first and second shuttles 2812 and 2822 reach their respective distal and proximal ends in their respective second and third slots 3320 and 3330.

[0130] In the configuration illustrated above, the slots lie on the same line parallel to the longitudinal direction of the implant and are not angularly offset from one another (for example, the slots are centered at approximately the same angle to one another when the implant is viewed from its top or bottom). In other implementations, one or more of the slots may be positioned so that they do not lie on the same line parallel to the longitudinal direction of the implant. The slots may be angularly offset from one another (for example, by a degree or some other angle). Examples of this are shown in Figures 36 and 37.

[0131] Figure 36 shows a side view of implant 3600 having a first slot 2810 and a second slot 2820 (shuttle and other features are omitted for ease of visualization). The long axis extends along the length of implant 3600. Figure 37 shows a simplified proximal end view of implant 3600. As can be seen from this figure, slots 2810 and 2820 are positioned with a 180-degree offset from each other. However, in other implementations, the offset can be at least n degrees, where n is an integer between 0 and 180. For example, in the illustrated configuration, the first slot 2810 is rotated 180° around the long axis relative to the second slot 2820.

[0132] In the configuration illustrated above, the slots do not overlap in the same plane perpendicular to the length of the implant. However, the implant may be configured in this way. Figure 38 shows implant 3700, an alternative version of implant 3600. Implant 3700 has slots 2810 and 2820 that are angularly offset from each other and overlap for an overlap zone 3710. The overlap zone 3710 may be sized to allow the shuttles to come together in a way that can compress the bone segments together, for example, to improve healing.

[0133] In the configuration illustrated above, the multiple slots of the implant are approximately the same length, but this is not necessarily required. One slot can be longer than another. For example, one slot can be at least x% of the length of another slot, where x is an integer between 0 and 100.

[0134] As described herein, implants in various implementations can be used to assist in the treatment of leg length inequality and / or bone defects in a patient's body. That is, implants disclosed according to various implementations are configured for intramedullary placement in a patient's body. In certain examples, implants are configured for use in methods of performing acute shortening and lengthening procedures on a bone segment. In these examples, implants are configured for bidirectional adjustment to assist acute shortening and subsequent lengthening, for example, to improve bone growth during the lengthening procedure. In certain examples, the acute shortening process applies pressure to the fusion point (to assist its fusion) before the start of the lengthening process. In certain examples, implants can be used in acute adjustment, for example, in a lengthening procedure following acute shortening performed by a surgeon on a given bone segment. For example, if a patient has a bone defect (e.g., a defect of about 10 cm), the surgeon may shorten the bone (e.g., only about 5 cm) and use the implant to transport (lengthen) the shortened bone to approximately its pre-operative length (e.g., transport about 5 cm). Following bone transport and docking, the surgeon may then create a new osteotomy and transport bone from another location (e.g., only an additional 5 cm) (e.g., using an implant) while the docking site heals. This exemplary technique can allow surgeons to address specific patient needs in a flexible manner, for example, by reducing transport time.

[0135] Additional implementations of the implants disclosed herein enable a method for performing a trifocal transport procedure. Further implementations of the implants disclosed herein enable a method for transporting the tibia and / or femur of a patient. In any case, the implants shown and described according to the various implementations enable the transport of multiple bones, for example, the transport of two or more bone segments by a single intramedullary implant.

[0136] In certain examples, the implants disclosed herein are configured for extramedullary placement in a patient. In certain cases, the system includes an implant and a biocompatible housing is configured for intramedullary placement. In these examples, the system further includes an extramedullary plate.

[0137] In certain embodiments, a method of using the implant described herein includes: i) implanting the implant in a patient and composing the proximal portion of the implant to the proximal bone portion; ii) composing the distal portion of the implant to the distal bone portion; iii) composing a first shuttle of the implant to a first bone segment between the proximal and distal bone portions; and iv) composing a second shuttle of the implant to a second bone segment between the proximal and distal bone portions. In certain implementations, the method further includes: v) moving the first shuttle at a first velocity in a first direction; and vi) moving the second shuttle at a second velocity in a second direction. In certain examples, the first and second directions are the same direction, and the second velocity is greater than the first velocity. In additional examples, the first and second directions are opposite convergence directions. In further examples, the first and second directions are opposite divergence directions. In certain cases, the movement of the first and second shuttles is performed simultaneously. In further cases, the movement of the first and second shuttles is performed sequentially. In certain cases, implanting an implant in a patient includes placing the implant intramedullarily. In other cases, implanting an implant in a patient includes placing the implant extramedullarily.

[0138] In an additional embodiment, the apparatus includes means for moving a first bone segment at a first velocity in a first direction, and means for moving a second shuttle at a second velocity in a second direction.

[0139] In additional implementations, the implant has adjustment dimensions defined by a patient adjustment profile for the patient's body. For example, grooves defining adjustment speed and / or range (groove diameter, pitch, grooves per centimeter, etc.), spring constant, gear ratio, etc., may be customized for the patient with respect to one or more physical properties. In certain examples, the groove pitch, number of grooves per centimeter, spring constant, and / or gear ratio are adjustable based on the patient adjustment profile. In such cases, the method of forming the implant (e.g., implant 110 and other implants illustrated herein) includes receiving at least one patient adjustment profile characteristic and, in the manufacture of the implant, assigning a value to at least one of groove pitch, grooves per centimeter, gear ratio, shuttle adjustment range, etc. In certain cases, the patient adjustment profile characteristic includes at least one of total translational distance, total rotations, translational speed, rotational speed, translation-to-rotation ratio, or adjustment period. The patient adjustment profile characteristic can be defined manually by a medical professional. Alternatively or additionally, the patient adjustment profile characteristic can be planned using surgical planning software. Once planned, patient adjustment profile characteristics can be used to assist the surgical team in manufacturing a custom implant (or a customized portion of an implant) for the patient, or in selecting an implant with an adjustment profile that is sufficiently close to the determined characteristics.

[0140] The implants shown and described herein can be configured for intramedullary placement within a patient's body, for example, to assist in the treatment of leg length inequality or bone defects within the patient's body. In certain cases, the implants described and illustrated herein can be used in methods of intramedullary adjustment of a patient's bone, for example, by inserting the implant into the patient's body and by activating the implant using a controller such as an external control device. In other examples, the implants may be configured for extramedullary placement.

[0141] In some examples, the implants described herein can be used as part of a bone transport system having a support member, the support member may be a bone plate configured to be fixed to a position on the outer surface of the bone to which the implant is implanted, or may include a bone plate. The bone plate may include a cortical bone plate. The support member may include one or more holes at its distal end for accommodating one or more bone screws. The support member may include one or more holes at its proximal end for accommodating one or more bone screws. The bone screws may be bicortical bone screws, or monocortical bone screws. Bicortical bone screws may be used at a position on the bone that is advantageously proximal or distal to the length-adjustable implant, and monocortical bone screws may be used at a position on the bone that is advantageously adjacent to the implant. The bone screws used to fix the support member to the bone may have a threaded shaft and a tapered threaded head, configured such that the threaded shaft engages with bone material and the tapered threaded head engages with tapered threaded holes (e.g., one or more holes) in the support member. The support member statically and stably maintains the proximal and distal portions of the bone relative to each other, thereby optimizing the accuracy of the transport portion's movement as it moves relative to the proximal and distal portions. One or more cell courages may be used to further secure the system in place, for example, to further fix the support member to the bone. In some embodiments, the support member may include a number of holes that can be considered for arranging bone screws. For example, a portion of the support member configured to be positioned at the proximal end of the femur may have three, four, or more holes for arranging bone screws that are fixed within the bone and configured to extend into the femoral neck, greater trochanter, or other portions of the femur including one or more bone fragments. Additional details regarding how the implants described herein may be used with the support member are described in U.S. Patent Application No. 16 / 046,909, which is incorporated herein by prior reference.

[0142] In some examples, the implants described herein may include extension loss resistance mechanisms such as those described in U.S. Patent Application No. 17 / 806,552 (filed June 13, 2022), which is incorporated herein by reference in its entirety for any purpose. In some examples, the implants described herein may include advanced sealing and retention features such as those described in PCT Application No. PCT / US2022 / 031709 (filed June 1, 2022), which is incorporated herein by reference in its entirety for any purpose. In some examples, the implants described herein may include multimodal adjustments such as those described in U.S. Patent Application No. 63 / 342,921 (filed May 17, 2022), which is incorporated herein by reference in its entirety for any purpose.

[0143] Any implant described herein may be part of an implantable adjustment system incorporating an external remote controller (ERC) or other external control device. In specific cases, the ERC may include a magnetic handpiece, a controller (or, for example, a control box with a processor), and a power supply. In additional implementations, the ERC or other external control device may include an interface, such as a user interface, to enable a medical professional to interact with the system including the implant described herein. Additional details relating to interaction with the ERC and the implant are described in U.S. Patent Application No. 16 / 298,339, which is incorporated herein by reference.

[0144] Furthermore, the implant, associated systems, and controllers may include a communication system for connecting the devices (e.g., via wireless or wired means) or integrated with a specific device (e.g., an ERC). The communication system may include several wired and / or wireless communication systems, having specific wireless systems configured to communicate via Bluetooth, Bluetooth Low Energy (BLE), radio frequency (RF), Wi-Fi, and / or ultrasound. In additional implementations, the communication system may include an independent subscriber identification module (SIM) assigned to each implant. In further cases, the communication system may be configured to communicate wirelessly with a remote control system and / or data acquisition / analysis platform, for example, via a cloud-based communication protocol.

[0145] In certain cases, each implant can be individually programmed to control the amount of bone adjustment in the patient. For example, each implant described herein may include individually programmable or adjustable components (e.g., programmable controllers and / or gear ratios, thread pitch and / or number) to control the amount of bone adjustment in the patient. In certain cases, separate implants in the system can be programmed or otherwise specified to make separate adjustments.

[0146] In additional cases, the controller described herein includes a smart device (e.g., a smartphone, smartwatch, tablet, etc.) configured to operate a control platform for adjusting implants. In these cases, the control platform may include a software application (or “app”) configured to run or otherwise operate on the controller (e.g., ERC) to enable control of one or more implants. Depending on the specific implementation, the control platform may enable control functions for one or more implants from a remote physical location relative to the device. For example, the control platform may enable connections (e.g., network-based and / or cloud-based connections) between a system including the implants described herein and remote users such as medical professionals.

[0147] In all implementations described herein, the implant may further include a feedback system that communicates with one or more control devices (e.g., an ERC and / or a software application that runs a control program). In certain cases, the feedback system provides feedback regarding the force response to adjustment of the length of a given adjustment rod and / or rotation of a given adjustment rod. In certain cases, the feedback system includes sensors mounted on the implant, e.g., sensors integrated with or coupled to the housing. Non-limiting examples of sensors may include load cells, piezoelectric sensors, or imaging sensors (e.g., optical sensors such as cameras, or ultrasonic sensors). Additional sensors that may be integrated with or otherwise form part of the feedback system may include position and / or velocity sensors (e.g., gyroscopes / magnetometers, or inertial measuring units (IMUs)), temperature sensors, and / or humidity sensors. In certain cases, the feedback system provides commands to a controller (e.g., an ERC) to modify the operation of a given implant based on feedback regarding the force response.

[0148] In yet another implementation, the sensors within the feedback system described herein may be configured to provide data on the load applied to the adjustment element and / or the load applied to the patient's bone by the adjustment element. The sensors may also provide data on the tensile load between the implant and the bone. In certain implementations, both torque and compression data are recorded by the sensors and provided to the feedback system for analysis and / or action (e.g., adjusting adjustment commands). It is understood that the torque and / or compression data detected by the sensors may represent an estimate or correlation index of torque and / or compression applied to a device or component that is not in physical contact with the sensor. For example, a sensor on an instrument may be configured to detect the torque of the instrument, which is translated (transferred) to a driven element in contact with the distal end of the instrument. Similarly, a sensor on an instrument may detect compression in the instrument, which is translated (transferred) to an external component, e.g., a driven element.

[0149] In additional implementations, one or more device components described herein, such as drive elements within an implant, may be communicatively coupled to a navigation system configured to detect the position of the device. In one example, a control unit (e.g., ERC) may include or otherwise communicate with a navigation system to provide navigation information regarding the position of the device. For example, the navigation system may include an optical tracking system such as a camera or laser-based tracking system, a Global Positioning System (GPS), an Inertial Measurement Unit (IMU), an ultrasonic-based measurement system, another type of positioning system, or a combination thereof. In specific cases, the navigation system may be configured to determine the distance the device has traveled when its position changes, and the navigation system may communicate this distance to the control unit (e.g., for processing by a feedback system). One or more components of the navigation system may be mounted on one or more components of the device, or located within or integrated with a coupled housing.

[0150] In certain cases, the feedback system or its functions may be integrated into a control unit and / or controller as described herein. In certain cases, the feedback system is part of a software application configured to determine, based on force feedback, what force adjustments, if any, should be made to a given implant. In some examples, the feedback system includes a model that correlates force response with the force applied during the adjustment of the implant length. The model may be based, for example, at least in part, on historical data from a set of implants in a separate bone fixation device similar to the implant described herein. According to various implementations, the model may be updated periodically or continuously to provide additional data about force response compared to the force applied to one or more implants. In certain cases, versions of the model may be downloaded or otherwise stored locally in one or more control units and / or controllers and updated periodically, for example, via cloud-based or other network-based software updates. This technique can reduce the computation and / or storage requirements in control units and controllers that may be local to the implant.

[0151] In additional implementations, the feedback system is configured to provide analysis of postoperative data, post-adjustment data, and alignment procedures and / or device usage, for example, to improve future procedures and / or diagnose inefficiencies in past procedures. In specific implementations, the feedback system is configured to update control commands for a control unit based on identified inefficiencies or errors in adjustments (e.g., extension, rotation) and / or device usage during / after a given procedure. In specific implementations, the feedback system includes a logic engine configured to iteratively modify commands, for example, on a procedure-by-procedure or patient-by-patient basis.

[0152] Various additional aspects of this disclosure may include a method for intramedullary adjustment of a patient's bone using the implants described herein. Using strictly Figures 2 and 3 for simplicity of explanation, the method may include (i) integrating the implant 110 into the patient's bone (e.g., via a bone screw or other fastener in a hole), and (ii) adjusting the length of the implant 110 using an external control device (e.g., an ERC or other remote controller). In particular cases, after adjusting the patient's bone, the method may further include (iii) separating the implant from the patient's bone (e.g., via a bone screw or other fastener in a hole).

[0153] In certain cases, the method may include imaging the bone connected to the implant described and illustrated herein. For example, the method may include (I) integrating or separating the implant (e.g., implant 110) from the patient's bone, and (II) imaging the bone after integration or separation using MRI and / or X-ray imaging. After imaging, the method may further include (III) (a) adjusting the already integrated implant (e.g., implant 110), or (b) separating the already integrated implant (e.g., implant 110) based on feedback from the imaging process.

[0154] As referred to herein, the implants and related methods described herein enable multiple bone adjustments, which can reduce the time and complexity associated with bone adjustment procedures. The various implementations disclosed can improve patient outcomes compared to conventional implantable adjusters, for example, by increasing adaptability in adjusting bone placement and improving both intraoperative and postoperative engagement with the device. Compared to conventional methods, the multiple bone (e.g., two or more bones) adjustment implants described according to the various implementations provide an efficient and simplified mechanism for bone adjustment. The implants described according to the various implementations can further reduce patient health risks compared to conventional methods, for example, by enabling a single implant to perform functions that were conventionally performed by multiple implantable devices (along with the associated implant procedures).

[0155] The functions described herein, or parts thereof, and various modifications thereof (hereinafter, "functions") may be implemented, at least in part, through computer program products, such as computer programs tangibly embodied in information carriers, such as one or more non-temporary machine-readable media, for execution by or control of the operation of one or more data processing devices, such as programmable processors, computers, multiple computers, and / or programmable logical components.

[0156] Computer programs can be written in any form of programming language, including compiled or interpreted languages, and can be deployed in any form, such as a standalone program, or as modules, components, subroutines, or other units suitable for use in a computing environment. Computer programs can be deployed to run on a single computer, on multiple computers at a single site, or on multiple computers distributed across multiple sites and interconnected by a network.

[0157] Operations related to implementing all or part of the functionality may be performed by one or more programmable processors that execute one or more computer programs to perform the functions of the calibration process. All or part of the functionality may be implemented as dedicated logic circuits, e.g., FPGAs and / or ASICs (Application-Specific Integrated Circuits). Processors suitable for executing computer programs include, for example, both general-purpose microprocessors and dedicated microprocessors, as well as any one or more processors of any type of digital computer. Generally, a processor receives instructions and data from read-only memory or random-access memory or both. The components of a computer include a processor for executing instructions and one or more memory devices for storing instructions and data.

[0158] In various implementations, components described as "coupled" to one another can be joined along one or more interfaces. In some implementations, these interfaces may include joints between separate components, while in other cases, these interfaces may include interconnects that are rigidly and / or integrally formed. That is, in some cases, "coupled" components can be formed simultaneously to define a single continuous member. However, in other implementations, these coupled components may be formed as separate members and then joined by known processes (e.g., soldering, fastening, ultrasonic welding, joining). In various implementations, electronic components described as "coupled" can be linked via conventional wired and / or wireless means so that these electronic components can communicate data with each other. Furthermore, subcomponents within a given component can be considered linked via conventional paths, although these are not necessarily illustrated.

[0159] Components with common symbols in the diagram are considered substantially equivalent for explanatory purposes, and redundant explanations of these components are omitted for clarity.

[0160] While the features of the present invention described herein are described in relation to preferred embodiments for achieving the objective, it will be understood by those skilled in the art that modifications can be achieved by taking these teachings into consideration without departing from the spirit or scope of the invention. Furthermore, although the invention has been described in accordance with its preferred use in spinal applications, it will be understood that the invention can be applied to a variety of other applications where surgical fixation is desired, such as the fixation of long bones.

[0161] Various exemplary embodiments of devices (e.g., implants) and technologies for moving bone within a patient's body are described herein. For clarity, not all features of actual implementations are necessarily described herein. Naturally, in the development of any such actual embodiment, it should be understood that numerous implementation-specific decisions will be made to achieve the developer's specific goals, such as compliance with system-related and business-related constraints that will vary from implementation to implementation. Furthermore, it should be understood that such development efforts, while complex and time-consuming, are customary work for those skilled in the art who are interested in this disclosure. The implants and related systems, program products, and methods described herein boast a variety of inventive features and components, individually or in combination, that guarantee patent protection.

[0162] It should be understood that any given element of the disclosed embodiments of the present invention may be embodied in a single structure, a single step, a single substance, etc. Similarly, a given element of the disclosed embodiments may be embodied in multiple structures, steps, substances, etc.

[0163] Several implementations have been described. Nevertheless, additional modifications can be made without departing from the scope of the concept of the present invention as described herein, and it is understood that other implementations are also within the scope of the following claims.

Claims

1. An implant for moving multiple separate bone segments between epiphyseal segments within a patient's body, wherein the implant is A transplantable biocompatible housing, A proximal hole for receiving a bone anchor attached to the proximal epiphyseal segment, A distal hole for receiving a bone anchor connected to the distal epiphyseal segment, and a biocompatible implant housing defining this hole, A first shuttle coupled to the housing and defining a first set of one or more holes for receiving a bone anchor coupled to a first bone segment in the plurality of bone segments, A second shuttle coupled to the housing and defining a second set of one or more holes for receiving a bone anchor coupled to a second bone segment in the plurality of bone segments, The system comprises a drive system that is at least partially disposed within the housing and configured to move the first and second shuttles relative to the housing, thereby moving the first and second bone segments, respectively. The first shuttle includes a first translationable rack mounted within the housing, and the second shuttle includes a second translationable rack mounted within the housing. Dental implants.

2. The drive system comprises at least one gear, and the implant is The first shuttle and the first rail coupled to the at least one gear, The implant according to claim 1, further comprising: a second rail coupled to the second shuttle and the at least one gear, wherein the movement of the first rail or the second rail translates to the movement of the first rail or the second rail toward the other.

3. The implant according to claim 2, wherein the drive system directly drives the first shuttle or the second shuttle, and indirectly drives the other of the first shuttle or the second shuttle.

4. The implant according to claim 3, wherein the drive system includes a magnetic driver, which is configured to be driven from a location outside the patient's body by an actuator in an external control device.

5. The implant according to claim 2, wherein the at least one gear includes a first gear and a second gear, and the first gear and the second gear are connected by a common shaft.

6. The implant according to claim 5, wherein the first gear and the second gear have separate gear ratios.

7. The aforementioned drive system is An electric driver configured to be driven by an actuator in an external control device from a position outside the patient's body, or The implant according to claim 1, comprising at least one ultrasonic drive driver configured to be driven by an actuator in an external control device from a location outside the patient's body.

8. The drive system and the lead screw coupled to the first shuttle, A first rack coupled to the first shuttle and the second shuttle, The second shuttle and the second rack coupled to the housing, The implant according to claim 1, further comprising the second shuttle, the first rack, and a rack gear coupled to the second rack.

9. The implant according to claim 8, further comprising a pinion gear between the rack gear and the second shuttle in order to change the gear ratio of the second shuttle to the rack gear.

10. The implant according to claim 8, wherein the first rack is fixed to the first shuttle, the second rack is fixed to the housing, and the second shuttle is configured to move relative to the first rack and the second rack.

11. The implant according to claim 10, wherein the drive system is configured to drive the translation of the lead screw, the first shuttle, and the first rack, the translation of the first rack engaging with the rack gear at a first speed and causing the translation of the second shuttle at a second separate speed.

12. The implant according to claim 1, wherein the drive system includes a first driver coupled to the first shuttle and a second driver coupled to the second shuttle, the first shuttle and the second shuttle being inserted axially between the first driver and the second driver.

13. The implant according to claim 12, wherein the first driver and the second driver each include a magnetic driver configured to be driven from a location outside the patient's body by an actuator in at least one external control device.

14. The implant according to claim 13, wherein the first driver and the second driver are axially separated to reduce magnetic field interference during operation by the external control device.

15. The implant according to claim 12, wherein the first driver and the second driver are configured to act for at least one of the convergence or serial transport of the plurality of bone segments.

16. The implant according to claim 1, wherein the drive system includes a single driver coupled to both the first shuttle and the second shuttle.

17. The implant according to claim 16, wherein the single driver includes a magnetic driver coupled with two separate gearboxes, and the operation of the magnetic driver causes either symmetric translation of the first shuttle and the second shuttle, or asymmetric translation of the first shuttle relative to the second shuttle.

18. The implant according to claim 1, wherein the housing includes a first sub-housing surrounding the first shuttle and a second sub-housing surrounding the second shuttle.

19. The implant according to claim 18, further comprising an extension rod extending axially between the first sub-housing and the second sub-housing.

20. A first lead screw in the first sub-housing is connected to the first portion of the extension rod, The extension rod is further comprising a second lead screw in the second sub-housing, which is coupled to the second portion of the extension rod, The drive system includes a first driver in the first sub-housing coupled to the first lead screw, and a second driver in the second sub-housing coupled to the second lead screw. The implant according to claim 19, wherein the first driver and the second driver can be controlled separately to translate the plurality of bone segments.

21. The implant according to claim 20, wherein the first lead screw has a first thread orientation, and the second lead screw has a second distinct thread orientation.

22. The implant according to claim 20, wherein the first driver and the second driver enable multi-stage extension of the plurality of bone segments.

23. The implant according to claim 1, further comprising an extension rod within the housing, wherein the first shuttle is located inside the extension rod and the second shuttle is driven by the extension rod.

24. The implant according to claim 23, wherein the drive system is coupled to the extension rod to drive the extension rod.

25. The implant according to claim 23, wherein the first shuttle includes a first threaded connection to the extension rod.

26. The implant according to claim 25, wherein the drive system includes a lead screw having a second threaded coupling to the extension rod, and the first threaded coupling and the second threaded coupling have separate thread pitches.

27. The implant according to claim 26, wherein the first threaded connector has a thread pitch that is half the thread pitch of the second threaded connector.

28. The drive system and the extension rod coupled to the first shuttle, The implant according to claim 1, further comprising the drive system and a cable assembly coupled to the second shuttle.

29. The implant according to claim 28, wherein the cable assembly includes a winding machine coupled to the drive system, the second shuttle and a cable connected to the winding machine, the operation of the drive system causes the extension rod and the first shuttle to translate, and the winding of the winding machine causes the second shuttle to translate.

30. The implant according to claim 29, further comprising a spring coupled to the second shuttle and providing reverse tension to the second shuttle during winding of the winding machine.

31. The implant according to claim 1, further comprising a lead screw coupled to the drive system, wherein each of the first shuttle and the second shuttle is directly coupled to the lead screw.

32. The implant according to claim 31, wherein the housing includes an axially extending slot that allows the bone anchor to be directly connected to each of the holes of the first set and the second set.

33. The implant according to claim 32, wherein the first shuttle and the second shuttle are configured to move axially along the slot.

34. The implant according to claim 33, wherein the lead screw includes a first threaded coupling portion with the first shuttle having a first thread pitch, and a second threaded coupling portion with the second shuttle having a second separate thread pitch.

35. A lead screw coupled to the aforementioned drive system, The lead screw and at least one band coupled to the first shuttle and the second shuttle, The implant according to claim 1, further comprising a reel coupled to at least one of the bands.

36. The implant according to claim 35, further comprising a tether coupled to the at least one band on the lead screw.

37. The implant according to claim 35, wherein the operation of the drive system causes the lead screw to move within the housing, thereby causing the first shuttle and the second shuttle to move via the at least one band.

38. The implant according to claim 35, wherein the housing includes axially extending slots that allow the bone anchors to be directly connected to the holes of the first set and the second set, respectively.

39. The implant according to claim 38, wherein the first shuttle and the second shuttle are configured to move axially along the slot.

40. The implant according to claim 35, wherein the reel is inserted axially between the first shuttle and the second shuttle.

41. The drive system and the lead screw coupled to the first shuttle, The implant according to claim 1, further comprising: a spring system coupled to the first shuttle and the second shuttle, configured to provide a translational differential between the first shuttle and the second shuttle when driven by the lead screw.

42. The implant according to claim 41, wherein a portion of the spring system is inserted axially between the first shuttle and the second shuttle.

43. The implant according to claim 42, wherein the spring system comprises a first spring and a second spring having separate spring constants, the first spring being inserted axially between the first shuttle and the second shuttle, and the second spring being inserted axially between the second shuttle and the distal end of the implant.

44. The implant according to claim 41, wherein when driven by the drive system and the lead screw, the first shuttle translates at a first velocity and the second shuttle translates at a separate second velocity.

45. The implant according to claim 44, wherein the second speed is at least half of the first speed.

46. The implant according to claim 41, wherein the spring system self-centers the first shuttle and the second shuttle relative to the housing in response to driving by the drive system.

47. The implant according to claim 1, wherein the first shuttle includes a drive system having a magnetic driver, a gearbox coupled to the magnetic driver, and a lead screw coupled to the gearbox, and a portion of the lead screw protrudes axially from the first shuttle.

48. The implant according to claim 47, wherein the magnetic driver is configured to be driven by an actuator in an external control device from a position outside the patient's body, and the operation of the magnetic driver causes the magnetic driver to be translated axially within the housing.

49. The implant according to claim 47, wherein the second shuttle is coupled to the lead screw and is configured to translate along with the movement of the lead screw.

50. The implant according to claim 49, wherein the magnetic driver includes a threaded coupling for changing the translational speed of the first shuttle relative to the second shuttle.

51. The implant according to claim 1, further comprising an extension rod housing the drive system, wherein the first shuttle is coupled to the drive system.

52. The implant according to claim 51, wherein the drive system includes a magnetic driver and a gearbox for driving a lead screw, and the first shuttle includes a rotation prevention mechanism for preventing the first shuttle from rotating while the lead screw is rotating.

53. The implant according to claim 52, wherein the second shuttle is coupled to the lead screw and configured to translate in proportion to the lead screw.

54. The implant according to claim 53, wherein the first shuttle is configured to translate disproportionately with respect to the lead screw.

55. The implant according to claim 1, wherein the first shuttle and the second shuttle each include a housing, and the set of one or more holes extends at least partially through the housing.

56. The implant according to claim 1, wherein the first shuttle and the second shuttle are configured to translate relative to the housing to move the first bone segment and the second bone segment according to a patient adjustment profile for the patient's body.

57. The drive system provides the first shuttle and the second shuttle, They move in the same direction at different speeds, or The implant according to claim 1, configured to move in the opposite direction of convergence or divergence.

58. The implant is the implant according to claim 1, wherein the implant is placed in the medulla of the patient.

59. The implant according to claim 1, wherein the implant is used to treat a leg length inequality or bone defect in the patient's body.

60. The implant according to claim 1, wherein the implant is positioned outside the medulla of the patient.

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