Intramedullary extension implant with integrated load sensor

Abstract

Intramedullary Extension Implant with Integrated Load Sensor Various implementations include implants for moving bone and related methods. A particular implementation includes an implant (10) for moving bone within a patient's body, the implant (10) including an implantable biocompatible housing (20), a first adjusting rod (40) at least partially overlapping the implantable biocompatible housing (20), a driver (50) configured to drive the first adjusting rod (40) to enable movement of the first adjusting rod (40) relative to the housing (20), and a load sensor (150) disposed within the housing (20) and configured to indicate a load applied to the first adjusting rod (40) by the driver (50).

Description

[Technical Field]

[0001] (Priority Claim) This patent application claims priority to U.S. Patent Application No. 17 / 887,789, filed August 15, 2022. The foregoing application is incorporated by reference as if fully set forth herein.

[0002] FIELD OF THE INVENTION The present disclosure relates generally to biocompatible implants, and more particularly to implants for moving bone within a patient's body. [Background technology]

[0003] Implantable bone adjustment systems can be beneficially used to treat a variety of conditions. For example, implantable bone adjustment systems can be used for distraction osteogenesis (also known as distraction prosthesis and bone distraction) in applications such as: post-osteosarcoma bone cancer; cosmetic lengthening (both legs—femur and / or tibia) in short stature or dwarfism / achondroplasia; lengthening one leg to match the other (congenital, post-traumatic, post-skeletal disorder, knee prosthesis), nonunion, and the like. Furthermore, implantable bone adjustment systems can be used to treat a variety of additional conditions and diseases, such as scoliosis or osteoarthritis (e.g., osteoarthritis). Further examples of therapeutic applications for implantable bone adjustment systems are described in U.S. Patent Application No. 16 / 298,339 (filed March 11, 2019) and U.S. Patent Application No. 13 / 370,966 (filed February 14, 2011), which are incorporated herein by reference in their entireties. Summary of the Invention

[0004] These and other needs are addressed by the embodiments of the implants and related methods described in this disclosure. All examples and features mentioned below can be combined in any technically possible manner.

[0005] Various implementations include implants, related systems, and methods for moving bone within a patient's body. Particular implementations include biocompatible implants with integrated load sensors.

[0006] In certain aspects, an implant for moving bone within a patient's body includes an implantable biocompatible housing, a first adjustment rod at least partially overlapping the implantable biocompatible housing, a driver configured to drive the first adjustment rod to enable movement of the first adjustment rod relative to the housing, and a load sensor disposed within the housing and configured to indicate a load applied to the first adjustment rod by the driver.

[0007] In a further specific embodiment, an implant for moving bone within a patient's body includes an implantable biocompatible housing having a first cavity, a first adjustment rod at least partially contained within the first cavity, a driver configured to drive the first adjustment rod to enable movement relative to the housing, the driver including a magnetic actuator configured to be actuated by a magnetic field external to the patient's body and a driven gear system coupled to the magnetic actuator, and a load sensor disposed between the driven gear system of the driver and the first adjustment rod, the load sensor indicating a load applied to the first adjustment rod by the driver.

[0008] In a further specific aspect, the method includes expanding an implanted distraction device using an external control device, measuring load sensor data using a load sensor of the implanted distraction device, and using the load sensor data to determine the amount of bone movement within the patient's body.

[0009] In additional particular aspects, a method of intramedullary conditioning of a patient's bone is performed using an implant described according to aspects of the present disclosure.

[0010] Implementations may include one or any combination of the following features.

[0011] In certain aspects, the implant is configured to be wirelessly coupled to an external control device for transmitting data from the load sensor.

[0012] In certain cases, the implant includes a wireless transmitter and one or more processors configured to cause the wireless transmitter to transmit data from the load sensor.

[0013] In certain implementations, the implantable biocompatible housing includes a first cavity defining an opening, the first adjustment rod is at least partially disposed within the first cavity, and the load sensor is disposed between the driver and the opening.

[0014] In some aspects, the driver includes a magnetic actuator configured to be actuated by a magnetic field external to the patient's body.

[0015] In certain implementations, the implant has a proximal end and a distal end, the driver further includes a driven gear system coupled to the magnetic actuator, the load sensor is proximal to the driver and the driven gear system is distal to the load sensor, hi some aspects, the interface between the housing and the driven gear system has a slip fit that allows for translation of the force measurement.

[0016] In certain cases, the load sensor includes a bi-directional load sensor coupled to the driver and configured to indicate both a compressive load and a tensile load applied by the driver to the first adjustment rod.

[0017] In some aspects, the load sensor is rotationally fixed relative to the housing. In certain embodiments, a rotatably fixed load sensor prevents rotation.

[0018] In certain implementations, the load sensor includes a button-type load cell, hi certain examples, the button-type load cell is configured to rotate.

[0019] In certain aspects, the load sensor is configured to monitor a load applied to the first adjustment rod by the driver during adjustment of the first adjustment rod.

[0020] In some cases, in the portion of the housing in which the load cell is disposed, the housing has a non-circular cross-section that restricts rotation of the load cell. In particular embodiments, the non-circular cross-section is oval or hexagonal.

[0021] In certain aspects, the implant further comprises a coupler that holds the load cell to a portion of the housing, hi certain embodiments, the coupler comprises a snap ring or an O-ring.

[0022] In certain implementations, the load sensor includes a bi-directional load sensor coupled to the driver and configured to indicate both a compressive load and a tensile load applied by the driver to the first adjustment rod.

[0023] In some embodiments, the proximal end of the first adjustment rod is configured to engage the lead screw and move with the lead screw.

[0024] In certain cases, the implant is an intramedullary implant.

[0025] In certain cases, the implant is configured to aid in the treatment of leg length inequality or bone defects within a patient.

[0026] In some cases, the load cell is configured to rotate with the driver relative to the housing.

[0027] In certain implementations, the load sensor includes a bi-directional load sensor coupled to the driver and configured to indicate both a compressive load and a tensile load applied by the driver to the first adjustment rod.

[0028] In some embodiments, the proximal end of the first adjustment rod is configured to engage the lead screw and move with the lead screw.

[0029] In certain cases, the load sensor allows for the determination of the amount of movement of bone within the patient's body without imaging the bone within the patient's body.

[0030] In certain implementations, the external control device is positioned adjacent to the patient's body during expansion of the implanted distraction device.

[0031] In some cases, the external control device is remote to the patient's body during expansion of the implanted distraction device.

[0032] In certain aspects, determining the amount of bone movement within the patient includes converting the load sensor data into an estimated bone movement value.

[0033] In some implementations, the estimated bone movement values ​​are compensated for a margin of error.

[0034] In certain cases, the load sensor is coupled to an external control device and configured to wirelessly transmit load data to the external control device. In some examples, the external control device is located proximate to the patient or remotely relative to the patient. In additional examples, the external control device includes an actuator for communicating with a driver in the implanted distraction device.

[0035] In certain implementations, the implants and methods allow for increased distraction rates in patients.

[0036] Two or more features described in this disclosure, including features described in this Summary section, may be combined to form implementations not specifically set forth herein.

[0037] The foregoing presents a simplified summary in order to provide a basic understanding of some aspects of the claimed subject matter. This summary is not an extensive overview. It is not intended to identify key or critical elements or to delineate 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 description that is presented later.

[0038] The details of one or more implementations are set forth in the accompanying drawings and the description below. Other features, objects, and advantages will be apparent from the description and drawings, and from the claims. [Brief explanation of the drawings]

[0039] [Figure 1] 1A-1D show perspective views of intramedullary implants according to various implementations. [Figure 2] 2A-2C illustrate cross sections of an implant such as the implant of FIG. 1 according to various implementations. [Figure 3] 3A-3C are enlarged cross-sectional views of a portion of the implant of FIGS. 1 and 2 according to various implementations. [Figure 4] FIG. 4 shows force / load diagrams for the implants of FIGS. 1-3 according to various implementations. [Figure 5] 10A-10C show cross sections of a portion of an implant according to various additional implementations. [Figure 6] 6A-6C are force / load diagrams for the implant of FIG. 5 according to various implementations. [Figure 7] 10A-10C show cross sections of a portion of an implant according to various implementations. [Figure 8] 8A-8D show enlarged cross-sectional views of a portion of the implant of FIG. 7 according to various implementations. [Figure 9] 1A-1D show partially transparent perspective views of a portion of an implant according to various implementations. [Figure 10] 10 shows cross sections of portions of the implants of FIGS. 7-9 according to various additional implementations. [Figure 11] 1A-1D show partially transparent perspective views of a portion of an implant according to various implementations. [Figure 12] 12 illustrates a cross section of a portion of the implant of FIG. 11 according to a particular implementation. [Figure 13] 13A-13D are force / load diagrams for the implant of FIG. 12 according to various implementations. [Figure 14] 10A-10C are cross-sectional views of implants including force / load indicators according to various additional implementations. [Figure 15] 1 is a flow chart illustrating processes in a method according to various implementations. [Figure 16] 10A-10C illustrate the internal components of an external adjustment device for non-invasively adjusting a distraction and compression device, according to various implementations. [Figure 17] 10A-10C illustrate various implementations of an external adjustment device configured for adjusting distraction and compression devices implanted within the femur and tibia, respectively. [Figure 18] 10A-10C illustrate various implementations of an external adjustment device configured for adjusting distraction and compression devices implanted within the femur and tibia, respectively.

[0040] It should be noted that the drawings of the various implementations are not necessarily to scale. The drawings are intended to depict only typical aspects of the disclosure and therefore should not be considered limiting of the scope of the implementations. In the drawings, like numbers represent like elements between the drawings. DETAILED DESCRIPTION OF THE INVENTION

[0041] Implantable bone conditioning systems have significantly improved patients' lives, for example, by enabling dynamic, long-term bone conditioning without significantly intruding on the patient's daily life. However, certain implantable bone conditioning systems can benefit from feedback regarding the forces applied by the implant, for example, in real time.

[0042] The present disclosure provides, at least in part, implants for moving multiple separate bone segments within a patient's body and methods for beneficially incorporating such implants for bone movement. These implants include a load sensor within the implant housing configured to directly or indirectly indicate a load applied to the patient's bone by the implant. In certain embodiments, the implant includes a housing having a driver configured to drive an adjustment rod, and a load sensor disposed within the housing and configured to indicate a load applied to the adjustment rod by the driver.

[0043] Various disclosed implementations can improve patient outcomes when compared to conventional implantable adjusters. The disclosed implementations can provide flexibility in adjusting bone alignment and improve intraoperative and / or postoperative device engagement. Additionally, the disclosed implementations can provide feedback on adjustment protocols for specific patients and / or groups of patients to improve adjustment outcomes for individuals and / or groups. Implants described according to various implementations can also reduce patient health risks compared to conventional approaches, for example, allowing for more aggressive (shorter) adjustment protocols and reducing the need for imaging as a means of adjustment feedback. Furthermore, force sensors can provide feedback to adjust the amount of treatment delivered to a patient (e.g., by directly measuring applied force in addition to or instead of measuring other indirect parameters).

[0044] FIG. 1 shows a schematic perspective view of an implant 10 for moving bone within a patient, according to various implementations. FIG. 2 shows a cross-sectional view of the implant 10. FIG. 3 shows an enlarged view of a portion of the implant 10. FIG. 4 shows a schematic markup of load transfer locations (interfaces) on the implant 10. In various implementations, the implant 10 (and other implants shown and described herein) are configured for intramedullary placement within a patient, for example, to aid in the treatment of one or more patient conditions. In certain embodiments, the implant 10 can be used in a method for intramedullary adjustment of a patient's bone. In certain embodiments, the implant 10 (and other implants herein) are configured to aid in the treatment of leg length inequality and / or bone defects within a patient. In other implementations, the techniques described herein can be applied to non-intramedullary applications, such as use with extramedullary plates, scoliosis correction, and other applications.

[0045] 1-4 , in various implementations, implant 10 includes an implantable biocompatible housing (or “housing”) 20. Housing 20 can include a first cavity 30, with first adjustment rod 40 at least partially housed within first cavity 30. Drive mechanism (or driver) 50 is configured to drive first adjustment rod 40 to enable axial movement of rod 40 relative to housing 20 (relative to major axis A), e.g., translation (also referred to as “distraction”). While particular implementations have been described with respect to translation (distraction), it is understood that additional implementations of the implant can include a driver configured to translate and / or rotate first adjustment rod 40 and / or additional adjustment rods, such as those described in U.S. Patent Application No. 63 / 342,921 (Implant with Multi-Modal Adjustment, filed May 17, 2022), which is incorporated herein by reference in its entirety.

[0046] In various implementations, the housing 20 and the first adjusting rod 40 are each configured to couple to a patient. In various implementations, the first adjusting rod 40 includes one or more holes 60 for receiving anchors to secure the implant 10 to the patient (e.g., to a bone), as shown in FIG. 1 . The housing 20 may further include one or more holes 70 for receiving anchors to secure the implant to the patient (e.g., to a bone). The spacing of the holes 60 relative to the distal end 80 of the implant 10, the spacing of the holes 70 relative to the proximal end 90 of the implant 10, the dimensions of the holes 60, 70, and other dimensional aspects of the holes 60, 70 can be tailored to specific patient parameters and / or treatment profiles. In certain embodiments, the anchors described herein may include bone screws or other bone fasteners or connectors. Examples of bone screws and / or dimensional aspects of the holes 60, 70 are described in U.S. Patent Application No. 16 / 298,339, which is incorporated herein by reference in its entirety.

[0047] In certain cases, the first adjusting rod 40 may include two separate portions that can be telescopically actuated to apply translational pressure to a patient's bone. For example, the portions of the first adjusting rod 40 may be configured to telescopically translate, for example, as described with reference to Figures 1-5 of U.S. Patent Application No. 16 / 298,339, previously incorporated by reference. In certain cases, the drive mechanism includes at least one driver 50 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 50 from a location outside the patient's body. In certain cases, the driver 50 is configured to control the translation of the first adjusting rod 40. In certain implementations, the driver 50 includes a gear system (e.g., a driven gear system with planetary gears) 120 for driving the movement of the first adjusting rod 40. In some embodiments, driven gear system 120 is coupled to a magnetic actuator (e.g., a permanent magnet) 130 that is rotationally coupled to driven gear system 120. However, other drive elements are suitable in place of magnets. For example, in addition to or instead of a magnet-based drive, one or more of the drive elements can take the form of an implanted electric motor. The implanted electric motor can be powered by an external power source (e.g., via a radio frequency link, via an inductive connection, or via another technique). The implanted electric motor can be powered by an implanted power source (e.g., a battery that can be charged by an external power source). The implanted power source can be within the implant (e.g., within its housing) or separate from the implant and coupled to the implant via a cable. In certain cases, driven gear system 120 is attached to a lead screw 140 that drives the translation of first adjusting rod 40 using radial and / or thrust bearings. That is, a proximal end 142 of first adjusting rod 40 is configured to engage and move with lead screw 140. As described herein, the driver 50 can be configured to control the translation of the first adjustment rod 40 .In some cases, the driven gear system 120 may have a partial (or complete) slip-fit ​​connection with the housing 20, allowing force to be transmitted to the load cell 150, for example, to provide an accurate measurement of the load applied by the driven gear system 120 to the lead screw 140.

[0048] In certain cases, the implant 10 further includes a load sensor 150 disposed within the housing 20 and configured to indicate a load applied by the driver 50 to the first adjustment rod 40. In some cases, the load sensor 150 is configured to monitor a load applied by the driver 50 to the first adjustment rod 40 during adjustment of the first adjustment rod 40. As described according to various implementations, the load sensor 150 can include a bidirectional load sensor coupled to the driver 50 and configured to indicate both a compressive load and a tensile load applied by the driver 50 to the first adjustment rod 40. In additional implementations, the load sensor 150 can include a unidirectional load sensor coupled to the driver 50 configured to indicate one of a compressive load or a tensile load applied by the driver 50 to the first adjustment rod 40. In certain implementations, the load sensor 150 is rotatably fixed relative to the housing 20, for example, to prevent rotation during driving of the first adjustment rod 40. In additional implementations, the load sensor 150 can rotate relative to the housing 20. In the particular embodiment shown in FIG. 2, the load sensor 150 includes a button-type load cell that may be rotated relative to the housing 20 in certain cases.

[0049] In certain implementations, as shown in, for example, FIGS. 2 and 4 , the implant 10 further includes a communication device 160 configured to transmit data from the load sensor 150. In certain cases, the communication device 160 includes a wireless transmitter that includes, and / or is coupled to, a processor or set of processors configured to cause a transmitter to transmit data from the load sensor 150. In various implementations, the communication device 160 enables wireless communication with an external control device, for example, by enabling transmission of data, such as load data, from the load sensor 150. In certain examples, the load sensor 150 is coupled to the external control device and configured to wirelessly transmit the load data to the external control device. In some examples, the external control device is located proximate to the patient or remotely relative to the patient. In additional examples, the external control device includes an actuator for communicating with a driver within the implant 10.

[0050] 2-4 , in certain implementations, the housing 20 is shown with a cavity 30 having an opening 170. In certain cases, the first adjustment rod 40 is at least partially disposed within the cavity 30. In additional implementations, the load sensor 150 is disposed within the housing 20, and the driver 50 is disposed between the load sensor 150 and the opening 170. That is, in various implementations, the load sensor 150 is proximal to the driver 50 (i.e., closer to the proximal end 90 of the implant 10) and the driver 50 is distal to the load sensor 150 (i.e., closer to the distal end 80 of the implant 10).

[0051] In certain implementations, as shown in the exemplary depictions of Figures 2-4, the implant may include a button-type load sensor 150 (or load cell) configured to detect a load applied to the first adjustment rod 40. In such cases, the load sensor 150 may be configured to rotate relative to the housing 20, e.g., about the primary axis (A) of the implant 10. In particular, Figure 4 shows an example of force / load transfer between components within the implant 10 as detected by the load sensor 150. The force (load) transfer diagram shows the reaction force transferred to the load sensor 150 resulting from actuation of the driver 50. As shown, load is transferred from the lead screw 140 to the coupler 180 in a first stage (1), from the coupler 180 to the thrust bearing 190 in a second stage (2), from the thrust bearing 190 to the ring gear 200 in a third stage (3), from the ring gear 200 to the magnet housing 210 for the magnetic actuator (magnet) 130 in a fourth stage (4), and from the magnet housing 210 to the load sensor 150 (e.g., button interface 220 in the load sensor 150) in a fifth stage (5). In certain implementations, the button-type load sensor 150 and configuration shown in FIGS. 2-4 are suitable for detecting compressive loads. The button-type load sensor 150 may have a cylindrical shape. In this example, the load sensor 150 is configured to detect a load applied to the first adjusting rod 40 by the driver 50 and, in certain cases, transmit the load data to an external control device (e.g., via the communication device 160 and associated processor). In certain cases, the processor may be coupled with a memory for locally storing the load data. In additional cases, the external control device may include a memory for storing the load data.

[0052] 5 and 6 illustrate another implementation of an implant 10A according to an embodiment of the present disclosure. FIG. 5 illustrates a cross section of the implant 10A, and FIG. 6 illustrates a schematic force / load transfer diagram of the implant 10A. According to certain implementations, the load sensor 150A within the implant 10A is rotationally fixed relative to the housing 20. That is, in certain implementations, a coupler 300 holds the load sensor 150A within a portion 310 of the housing 20. In certain cases, the load sensor 150A is secured to the housing 20 using the coupler 300, which may include one or more pins, screws, bolts, or the like. According to some implementations, the load sensor 150A directly contacts the magnet housing 210 of the magnetic actuator 130. In certain cases, the fixed position of the load sensor 150A (e.g., via the coupler 300, such as a pin, screw, bolt, or the like) allows the load sensor 150A to detect both compressive and tensile loads translated from the adjustment rod 40. In certain cases, the coupler 300 can include a set of spring-loaded pins (e.g., two pins) that mate with recesses in the housing 20, thereby retaining the load sensor 150A within the housing 20 without extending through the exterior surface of the housing 20. In either case, as described herein, the implant 10A can be configured to detect one or both compressive and tensile loads, for example, to assist in determining operating parameters of the implant 10A within the patient's body. FIG. 6 illustrates load transfer in both compressive and tensile modes. Load transfer in compressive mode is similar to the description of FIG. 4. In tension mode, tension on the lead screw 140 is transferred to the coupler 180, then to the opposite side of the thrust bearing 190, then to the edge of the wedge lock 320, from the wedge lock 320 to the ring gear 200 / magnet housing 210 interface, and then from the magnet housing 210 to the load sensor 150A.

[0053] 7 and 10 illustrate another implant 10B according to an additional implementation. As described herein, a portion of the housing 20 within the implant 10B is configured with a torque-limiting (or rotation-limiting) feature. In one example, as shown in FIG. 7, a portion 330 of the housing 20 within the implant 10B houses a load sensor 150A, such as a bidirectional load sensor similar to the load sensor 150A of FIG. 6. In these embodiments, the portion 330 of the housing 20 in which the load sensor 150A is disposed has a non-circular cross-section 340 that limits rotation of the load sensor 150A. In certain cases, the load sensor 150 is approximately non-circular, and in certain cases, complements the non-circular cross-section 340 of the housing. In other cases, the load sensor 150 is approximately circular and interferes with the non-circular cross-section 340 of the portion 330 of the housing 20. FIG. 8 illustrates an enlarged perspective view of the non-circular cross-section 340 illustrating an exemplary rotation-limiting feature of the housing 20. That is, an inner wall (surface) 350 of the housing 20 is non-circular (e.g., oval, hexagonal, etc.) and an outer wall (surface) 360 of the load sensor 150A is non-circular or approximately circular, causing interference between the two surfaces 350, 360. In certain implementations, a coupler 370 holds the load sensor 150A within the portion 330 of the housing 20. The coupler 370 may include a snap ring, O-ring, or other retention feature disposed at least partially circumferentially around a recess (or notch) 380 in the outer surface 360 ​​of the load sensor 150A.

[0054] Additionally, FIG. 8 illustrates a circuit 810. The circuit 810 may be electrically connected to one or more of the load sensors 150. The circuit 810 may include one or more power storage components, such as one or more batteries or capacitors. The power storage components may provide power to one or more other components of the circuit 810, such as one or more of the load sensors 150, or other components of the implant 10. The circuit 810 may include one or more power generation components, such as those that may be used to obtain power from movement of the implant 10 (e.g., caused by movement of the implant recipient) or from conditions surrounding the implant (e.g., temperature). The circuit 810 may include one or more microcontrollers (e.g., one or more processors, such as a central processing unit) and / or memory circuits. The circuit 810 may further include one or more components configured for bidirectional or unidirectional communication with an external device. Communication may include receiving power from the external device (e.g., to charge one or more of the power storage components). Communication may include receiving commands from the external device. The communication may include providing data (e.g., load data from one or more load sensors) to an external device. Circuitry 810 may include one or more aspects, configurations, or components as described in U.S. Patent No. 2020 / 0253588 (filed February 7, 2020), U.S. Patent No. 11,389,111 (filed January 17, 2019), and U.S. Patent No. 2019 / 0254712 (filed April 30, 2019), each of which is incorporated by reference herein in its entirety for all purposes.

[0055] 9 and 10 show partial perspective and cross-sectional views, respectively, of a portion of implant 10B including coupler 370. In some implementations, coupler 370 helps retain load sensor 150A within housing 20, for example, axially or proximal-distal.

[0056] 11 and 12 show partially transparent perspective and cross-sectional views, respectively, of another implant 10C according to various implementations. Similar to implant 10B, in implant 10C, a portion 330 of housing 20 houses a load sensor 150A, such as a bidirectional load sensor. In these embodiments, the portion 330 of housing 20 in which load sensor 150A is disposed has a non-circular cross-section 340 that limits rotation of load sensor 150A. In certain embodiments, an inner wall (surface) 350 of housing 20 includes at least one flat portion 352, and more particularly, multiple flat portions 352. In certain cases, flat portion 352 of inner wall (surface) 350 complements flat portion 354 of outer surface 360 ​​of load sensor 150A. In certain embodiments, inner wall (surface) 350 of housing 20 has a substantially hexagonal cross-section. In additional implementations, outer surface 360 ​​of load sensor 150A is circular or nearly circular, causing interference between the two surfaces 350, 360. In certain implementations, a coupler 370 holds the load sensor 150A within the portion 330 of the housing 20. The coupler 370 may include a snap ring, O-ring, or other retention feature disposed at least partially circumferentially around a recess (or notch) 380 in the outer surface 360 ​​of the load sensor 150A. In some implementations, the coupler 370 helps to hold the load sensor 150A within the housing 20, for example, axially or proximally-distally. In additional implementations, a second coupler 372 (e.g., a snap ring or O-ring) is disposed between the second recess (or notch) 382 in the load sensor 150A and the magnet housing 210, for example, to secure the load sensor 150A to the magnet housing 210 and the connected ring gear 200.

[0057] 13 is an exemplary force loading diagram for implant 10B and / or implant 10C according to various implementations. As shown, bi-directional load sensor 150A is positioned to detect forces applied from either direction (e.g., pulling or pushing) to the interface between magnet housing 210 and ring gear 200. Regardless of the rotation-limiting geometry of the load sensor and housing, the ability to detect force loads is approximately the same between both implants 10B and 10C.

[0058] FIG. 14 shows a cross section of an additional implant 10D according to various additional implementations. In contrast to certain other implants shown and described herein, implant 10D includes a load sensor 150A (e.g., a bidirectional load sensor) disposed between (e.g., axially in a proximal-distal direction) driven gear system 120 of driver 50 and first adjusting rod 40 to indicate, for example, the load applied to first adjusting rod 40 by driver 50. In certain implementations, load sensor 150A is directly coupled to driver 50 (e.g., adjacent driven gear system 120) and configured to rotate with driver 50 relative to housing 20. As with other implementations utilizing load sensor 150A, implant 10D is configured to detect both compressive and tensile loads on first adjusting rod 40, as indicated by the tensile load arrow (left to right) and the compressive load arrow (right to left) in FIG. 14 . In these implementations, the compressive load can be sensed via a coupler 180A connected directly to the rear (opposite) side of the load sensor 150A from the connection to the lead screw 140.

[0059] FIG. 15 is a flow chart illustrating a method of using an implant (e.g., implant 10 or any of implants 10A-D) according to certain implementations. In various implementations, the process occurs while the implant is implanted within a patient, e.g., while coupled to one or more bone segments within the patient. First, process P1: The implant 10 is expanded using an external control device, such as a controller described herein. In certain cases, the external control device is positioned proximate to the patient's body during expansion of the implant 10. In other cases, the external control device is remote from the patient's body during expansion of the implant 10. Concurrent with process P1 or following expansion in process P1, load sensor data is measured using load sensor 150 of implant 10 (e.g., load sensor 150 and / or load sensor 150A). Following measurement of the load sensor data by load sensor 150, the amount of bone movement within the patient's body is determined in process P3. In certain cases, determining the amount of bone movement within the patient's body includes converting the load sensor data to an estimated bone movement value. In some embodiments, a data model is used to estimate bone movement values, e.g., applying a correspondence table or other calculation to account for load sensor data, patient-specific data, implant-specific data, etc. In certain cases, the estimated bone movement value compensates for a margin of error. In some embodiments, movement is determined based on a known or estimated amount of load over time required to move a certain amount of bone. This amount can be adjusted based on the known movement of the patient. For example, an initial image of the region of interest can be taken, the implant can be actuated while the load is measured, and subsequent images can be taken. The amount of load can be correlated to visible bone changes by comparison between the initial and subsequent images. In some embodiments, the change in the amount of load can be used to determine the amount of bone movement or when the next bone adjustment can occur.

[0060] In any event, the use of load sensors (e.g., load sensor 150 and / or load sensor 150A) allows for the determination of bone movement within a patient without imaging of that bone. That is, the implants shown and described herein can reduce reliance on imaging as feedback for bone adjustment in a patient, potentially reducing patient exposure to imaging-based radiation and additional complications.

[0061] The implants shown and described herein (e.g., implants 10, 10A, 10B, 10C, 10D) can be configured for placement intramedullary in a patient to aid in the treatment of leg length inequality or bone defects within the patient. In certain cases, the implants described and illustrated herein can be used in a method for intramedullary conditioning of a patient's bone, for example, by inserting the implant into the patient and actuating the implant using a controller, such as an external control device. As described herein, further processes in the method can include measuring load sensor data from a load sensor in the implant and using the load sensor data to determine bone movement within the patient.

[0062] 16-18 illustrate an external adjustment device 400 configured to enable non-invasive adjustment of device 100 by applying a moving magnetic field to rotate a permanent magnet 202 within device 100, as described. FIG. 16 illustrates the internal components of external adjustment device 400, showing the permanent magnet 202 of device 100 without the remainder of the assembly for clear reference. The internal operating components of external adjustment device 400 may, in certain embodiments, be similar to those described in U.S. Patent Application Publication No. 2012 / 0004494 (incorporated herein by reference). A motor 402 with a gearbox 404 outputs to a motor gear 406. The motor gear 406 engages and rotates a central (idle) gear 408 having a suitable number of teeth to rotate a first magnet gear 410 and a second magnet gear 412 at the same rotational speed. The first magnet 414 and the second magnet 416 rotate in conjunction with the first magnet gear 410 and the second magnet gear 412, respectively. Each magnet 414, 416 is held within a respective magnet cup 418 (partially shown). An exemplary rotational speed may be 60 RPM or less. This speed range may be configured to limit the amount of current density induced in body tissue and fluids and meet international guidelines or standards. As seen in FIG. 16 , the south pole 422 of the first magnet 414 faces in the same direction as the north pole 424 of the second magnet 416, and similarly, the first magnet 414 has a north pole 426 that faces in the same direction as the south pole 428 of the second magnet 416. When these two magnets 414, 416 rotate together in sync, they apply complementary and additive moving magnetic fields to the radially polarized permanent magnet 202 having a north pole 432 and a south pole 434. Magnets having multiple north poles (e.g., two) and multiple south poles (e.g., two) are also contemplated in each of the devices. When the two magnets 414, 416 rotate in a first rotational direction 442 (e.g., counterclockwise), magnetic coupling causes the permanent magnet 202 to rotate in an opposite second rotational direction 444 (e.g., clockwise). The rotational direction of the motor 402 and the corresponding rotational direction of the magnets 414, 416 are controlled by buttons 446, 448.One or more circuit boards 452 contain control circuitry for both sensing the rotation of the magnets 414, 416 and controlling the rotation of the magnets 414, 416.

[0063] FIGS. 17 and 18 show an external adjustment device 400 for use with the device 100 placed in the femur ( FIG. 17 ) or tibia ( FIG. 18 ). The external adjustment device 400 has a first handle 454 for carrying or stabilizing the external adjustment device 400, for example, for stabilizing it relative to the upper thigh 456 (as in FIG. 17 ) or the lower thigh 457 (as in FIG. 18 ). An adjustable handle 458 is rotatably attached to the external adjustment device 400 at pivot points 460, 462. The pivot points 460, 462 have lockable / unlockable mechanisms, such as spring-loaded brakes, ratchets, or clamping screws, that allow the adjustable handle 458 to be adjusted to a desired angle relative to the housing 464 and to lock the orientation. The adjustable handle 458 is shown in two different positions in FIGS. 17 and 18 . In FIG. 17 , the adjustable handle 458 is set so that the apex 466 of the loop 468 rests against the housing 464. In this position, the patient 470 can grasp one or both of the grips 472, 474 while the adjustment procedure (e.g., moving the bone between 0.10 mm and 1.50 mm) is performed. It is contemplated that the procedure may be a distraction procedure for a bone distraction device or a distraction plate attached externally to the bone. Looking at FIG. 18 , when the bone transport device 100 is implanted in the tibia, the adjustable handle 458 can be repositioned to allow the patient 470 to grasp the apex 466 so that the magnet region 476 of the external adjustment device 400 is held above the portion of the device 100 containing the permanent magnet 202. In either case, the patient 470 can clearly view the control panel 478, which includes the display 482. 16 , the control panel 478 includes a start button 484, a stop button 486, and a mode button 488. Using control circuitry contained on the circuit board 452, the surgeon can store information regarding the specific aspects of each particular patient. For example, in some patients, the implant may be placed antegrade in the tibia. In other patients, the implant may be placed either antegrade or retrograde around the femur.In each of these three cases, it may be desirable to move the bone either distally to proximally or proximally to distally. By having the ability to store this type of information specific to each particular patient within the external adjustment device 400, the external adjustment device 400 can be configured to automatically instruct the magnets 414, 416 to rotate in the correct direction; the patient simply places the external adjustment device 400 in the desired position and presses the start button 484. The maximum allowable bone transport length per day and the maximum allowable bone transport length per session can also be entered and stored by the surgeon for safety purposes. These may also be added via a memory storage unit (e.g., an SD card, a USB device, etc.) or by wireless input (e.g., Bluetooth, WiFi, etc.). An additional feature is a camera located on the portion of the external adjustment device 400 that rests on the skin. For example, the camera could be located between the first magnet 414 and the second magnet 416. The skin directly overlying the implanted permanent magnet 202 can be marked with indelible ink. A live image from the camera is then displayed on the display 482 of the control panel 478, allowing the user to position the first magnet 414 and the second magnet 416 directly over the area marked on the skin. Crosshairs can be superimposed on the live image on the display 482, allowing the user to align the mark on the skin between the crosshairs and thus optimally position the external adjustment device 400.

[0064] Other external adjustment devices can be used to cause actuation of the distraction devices described herein. Such external adjustment devices include, for example, those described in U.S. Patent No. 8,382,756, filed November 20, 2009, U.S. Patent No. 9,248,043, filed June 29, 2011, U.S. Patent No. 9,078,711, filed June 6, 2012, U.S. Patent No. 9,044,281, filed October 18, 2012, U.S. Patent Application No. 14 / 698,665, filed April 28, 2015, U.S. Patent Application No. 14 / 932,904, filed November 4, 2015, U.S. Patent Application No. 16 / 004,099, filed December 12, 2016, and International Publication No. WO 2020 / 017338, filed February 7, 2020, all of which are incorporated by reference herein as if set forth in their entireties.

[0065] Additionally, any of the implants described herein can be part of an implantable regulation system that incorporates an external remote controller (ERC) or other external control device. In certain cases, the ERC can include a magnetic handpiece, a controller (or a control box, e.g., with a processor), and a power source. In additional implementations, the ERC or other external control device can include an interface, such as a user interface, to allow a medical professional to interact with a system including the implants described herein. Additional details regarding ERCs and interaction with implants are described in U.S. Patent Application Serial No. 16 / 298,339, which is incorporated herein by reference.

[0066] Additionally, implants, associated systems, and controllers may include communication systems for connecting devices (e.g., via wireless or wired means) or integrated with specific devices (e.g., ERCs). The communication systems may include several wired and / or wireless communication systems, with 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 systems may include a separate subscriber identity module (SIM) assigned to each implant. In further cases, the communication systems are configured to communicate wirelessly with a remote control system and / or a data collection / analysis platform, for example, via a cloud-based communication protocol.

[0067] In certain cases, each implant is individually programmable to control the amount of adjustment of the patient's bone. For example, each of the implants described herein may include individually programmable or adjustable components (e.g., programmable controllers and / or gear ratios, thread pitch and / or number, etc.) to control the amount of adjustment of the patient's bone. In certain cases, separate implants within a system can be programmed or otherwise designated to provide separate adjustments.

[0068] 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 coordinating implants. In these cases, the control platform may include a software application (or "app") configured to execute or otherwise run on the controller (e.g., ERC) to enable control of one or more implants. According to certain implementations, the control platform enables control functions for one or more implants from a physical location remote to the device 100. For example, the control platform may enable connectivity (e.g., network-based and / or cloud-based connectivity) between a system including the implants described herein and a remote user, such as a medical professional.

[0069] In all implementations described herein, the implant can further include a feedback system in communication with one or more control devices (e.g., the ERC and / or a software application executing the control program). In certain cases, the feedback system provides feedback regarding the force response to a given adjustment rod length adjustment and / or a given adjustment rod rotation. In certain cases, the feedback system includes a sensor onboard the implant, e.g., a sensor integrated with or coupled to the housing. Non-limiting examples of sensors can include load cells, piezoelectric sensors, or imaging sensors (e.g., optical sensors such as cameras, or ultrasonic sensors). Additional sensors that can be integrated into or otherwise form part of the feedback system can include position and / or velocity sensors (e.g., gyroscopes / magnetometers or inertial measurement units (IMUs)), temperature sensors, and / or humidity sensors. In certain cases, the feedback system provides instructions to a controller (e.g., the ERC) to alter the operation of a given implant based on feedback regarding the force response.

[0070] In yet another implementation, sensors in the feedback systems described herein can be configured to provide data regarding the load applied to the adjustment element and / or the load applied to the patient's bone by the adjustment element. The sensors can also provide data regarding the tensile load between the implant and the bone. In certain implementations, both tension and compression data are recorded by the sensors and provided to the feedback system for analysis and / or action (e.g., adjusting adjustment instructions). It is understood that tension and / or compression data detected by the sensors can represent an estimate or correlated indicator of tension and / or compression applied to a device or component not in physical contact with the sensor. For example, a sensor on the instrument can be configured to detect tension in the instrument, which torque is translated into a driven element contacting the distal end of the instrument. Similarly, a sensor on the instrument can detect compression in the instrument, which compression is translated into an external component, e.g., a driven element.

[0071] In additional implementations, one or more device components described herein, e.g., drive elements within an implant, can be communicatively coupled to a navigation system configured to detect the position of the device. In one example, a control unit (e.g., an ERC) can include or otherwise communicate with a navigation system to provide navigation information regarding the position of the device. For example, the navigation system can 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 ultrasound-based measurement system, other types of position systems, or combinations thereof. In certain cases, the navigation system is configured to determine the distance traveled by the device when its position changes, and the navigation system communicates the distance to the control unit (e.g., for processing by a feedback system). One or more components of the navigation system can be disposed within or integrated with a housing attached to or coupled to one or more components of the device.

[0072] In certain cases, the feedback system or its functionality can be integrated into a control unit and / or controller as described herein. In certain cases, the feedback system is part of a software application and is configured to determine what force adjustments, if any, should be made for a given implant based on the force feedback. In some examples, the feedback system includes a model that correlates force response with the force applied during implant length adjustment. The model can be based, for example, at least in part, on historical data from a set of implants in separate bone fixation devices similar to the implants described herein. According to various implementations, the model can be periodically or continuously updated to provide additional data on the force response compared to the force applied to one or more implants. In certain cases, a version of the model can be downloaded or otherwise stored locally in one or more control units and / or controllers and periodically updated, for example, via cloud-based or other network-based software updates. This approach can reduce computational and / or storage requirements in control units and controllers that may be local to the implants.

[0073] In additional implementations, the feedback system is configured to provide post-operative data, post-adjustment data, and analysis of alignment procedures and / or device use, e.g., to improve future procedures and / or diagnose inefficiencies in past procedures. In certain implementations, the feedback system is configured to update control instructions for the control unit based on identified inefficiencies or errors in the amount of adjustment (e.g., extension, rotation) and / or device use during / after a given procedure. In certain implementations, the feedback system includes a logic engine configured to iteratively modify instructions, e.g., from procedure to procedure or from patient to patient.

[0074] Various additional aspects of the present disclosure can include methods of intramedullary preparation of a patient's bone using the implants described herein. Using FIGS. 1 and 2 strictly for ease of explanation, the method can include (i) coupling implant 10 to the patient's bone (e.g., via bone screws or other fasteners in holes 60, 70), and (ii) preparing the patient's bone using an intramedullary implant such as implant 10 by actuating a length adjustment and / or a rotation of implant 10 using an external control device (e.g., an ERC or other remote controller). The length adjustment can occur before, during, or after the rotation adjustment. In certain cases, after preparing the patient's bone, the method can further include (iii) detaching the implant from the patient's bone (e.g., via bone screws or other fasteners in holes 60, 70).

[0075] In certain cases, the method may include imaging a bone connected with an implant described and illustrated herein. For example, the method may include (I) coupling or detaching an implant (e.g., implant 10) to a patient's bone and (II) imaging the bone using MRI and / or X-ray imaging after coupling or detachment. After imaging, the method may further include (III) either (a) adjusting the already coupled implant (e.g., implant 10) or (b) detaching the already coupled implant (e.g., implant 10) based on feedback from the imaging process.

[0076] As noted herein, the implants and related methods described herein enable effective feedback regarding bone adjustment procedures, reducing treatment times and complications associated with bone adjustment procedures. Various disclosed implementations can improve patient outcomes compared to conventional implants. For example, they can enable more aggressive adjustment profiles (when warranted), increase flexibility in adjusting bone position, and / or enhance intra- and post-operative engagement with the device. Compared to conventional approaches, the load-sensing implants described according to various implementations provide an efficient mechanism for bone adjustment and feedback regarding adjustment procedures. The implants described according to various implementations can also reduce patient health risks compared to conventional approaches, for example, by enabling the implant to provide adjustment feedback with less imaging exposure.

[0077] The functionality described herein, or portions thereof, and various modifications thereof (hereinafter "functionality"), may be implemented, at least in part, via a computer program product, e.g., a computer program tangibly embodied in an information carrier such as one or more non-transitory machine-readable media, for execution by or to control the operation of one or more data processing devices, e.g., a programmable processor, a computer, multiple computers, and / or programmable logic components.

[0078] A computer program can be written in any form of programming language, including compiled or interpreted languages, and can be deployed in any form, such as as a stand-alone program or as a module, component, subroutine, or other unit suitable for use in a computing environment. A computer program can be deployed to be executed on one computer, on multiple computers at one site, or on multiple computers distributed across multiple sites and interconnected by a network.

[0079] The operations associated with implementing all or a portion of the functionality may be performed by one or more programmable processors executing one or more computer programs to perform the functions of the calibration process. All or a portion of the functionality may be implemented as special purpose logic circuitry, e.g., an FPGA and / or an ASIC (application-specific integrated circuit). Processors suitable for executing computer programs include, by way of example, both general-purpose and special purpose microprocessors, as well as any one or more processors of any type of digital computer. Typically, a processor receives instructions and data from read-only memory or random-access memory or both. Components of a computer include a processor for executing instructions and one or more memory devices for storing instructions and data.

[0080] In various implementations, components described as being "coupled" to one another can be joined along one or more interfaces. In some implementations, these interfaces can include joints between separate components, while in other cases, these interfaces can include rigidly and / or integrally formed interconnects. That is, in some cases, components "coupled" to one another can be formed simultaneously to define a single, continuous member. However, in other implementations, these coupled components can be formed as separate members and then joined by known processes (e.g., soldering, fastening, ultrasonic welding, bonding). In various implementations, electronic components described as "coupled" can be linked via conventional wired and / or wireless means such that the electronic components can communicate data with one another. Additionally, subcomponents within a given component can be considered to be linked via conventional pathways, although not necessarily shown.

[0081] Components with common reference numerals in the figures are considered to be substantially equivalent components for purposes of explanation, and redundant descriptions of those components are omitted for clarity.

[0082] While the features of the invention described herein have been set forth in terms of preferred embodiments for accomplishing their objectives, it will be understood by those skilled in the art that variations can be achieved in light of these teachings without departing from the spirit or scope of the invention. Furthermore, while the invention has been described according to its preferred use in spinal applications, it will be understood that the invention may be applied to a variety of other applications where surgical fixation is desired, such as the fixation of long bones.

[0083] Various exemplary embodiments of devices (e.g., implants) and techniques for moving bone within a patient's body are described herein. In the interest of clarity, not all features of an actual implementation are necessarily described herein. Of course, it will be understood that in the development of any such actual embodiment, numerous implementation-specific decisions will have to be made to achieve the developer's specific goals, including compliance with system- and business-related constraints that will vary from implementation to implementation. It will further be appreciated that such a development effort may be complex and time-consuming, but would nevertheless be a routine undertaking for those of ordinary skill in the art having the benefit of this disclosure. The implants and related systems, program products, and methods described herein boast various inventive features and components that, individually and in combination, warrant patent protection.

[0084] 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. Likewise, a given element of the disclosed embodiments may be embodied in multiple structures, steps, substances, etc.

[0085] Although multiple implementations have been described, it is nevertheless understood that additional modifications may be made without departing from the scope of the inventive concepts described herein, and therefore, other implementations are within the scope of the following claims.

Claims

1. 1. An implant for moving bone within a patient's body, said implant comprising:

1. An implantable biocompatible housing, comprising: a first adjustment rod at least partially overlapping the implantable biocompatible housing; a driver configured to drive the first adjustment rod to enable movement of the first adjustment rod relative to the implantable biocompatible housing; a load sensor disposed within the implantable biocompatible housing and configured to indicate a load applied to the first adjustment rod by the driver.

2. The implant of claim 1 , wherein the implant is configured to be wirelessly coupled to an external control device for transmitting data from the load sensor.

3. 3. The implant of claim 2, wherein the implant comprises a wireless transmitter and one or more processors configured to cause the wireless transmitter to transmit data from the load sensor.

4. the implantable biocompatible housing includes a first cavity defining an opening; the first adjustment rod is at least partially disposed within the first cavity; The implant of claim 1 , wherein the driver is disposed between the load sensor and the opening.

5. The implant of claim 1 , wherein the driver comprises a magnetic actuator configured to be actuated by a magnetic field external to the patient's body.

6. 6. The implant of claim 5, wherein the implant has a proximal end and a distal end, the driver further comprising a driven gear system coupled to the magnetic actuator, the load sensor being proximal to the driver and the driven gear system being distal to the load sensor.

7. 10. The implant of claim 1, wherein the load sensor comprises a bi-directional load sensor coupled to the driver and configured to indicate both a compressive load and a tensile load applied by the driver to the first adjustment rod.

8. The implant of claim 7 , wherein the load sensor is rotatably fixed relative to the implantable biocompatible housing.

9. The implant of claim 1 , wherein the load sensor comprises a button-type load cell.

10. The implant of claim 1 , wherein the load sensor is configured to monitor the load applied to the first adjustment rod by the driver during adjustment of the first adjustment rod.

11. The implant of claim 1 , wherein in a portion of the implantable biocompatible housing where the load sensor is disposed, the implantable biocompatible housing has a non-circular cross-section that limits rotation of the load sensor.

12. The implant of claim 11 , further comprising a coupler that holds the load sensor within the portion of the implantable biocompatible housing.

13. 13. The implant of claim 12, wherein the load sensor comprises a bi-directional load sensor coupled to the driver and configured to indicate both a compressive load and a tensile load applied by the driver to the first adjustment rod.

14. The implant of claim 1 , wherein a proximal end of the first adjustment rod is configured to engage a lead screw and move with the lead screw.

15. The implant of claim 1 , wherein the implant is an intramedullary implant.

16. 10. The implant of claim 1, wherein the implant is configured to aid in the treatment of leg length inequality or bone defects within the patient.

17. 10. A method for intramedullary preparation of a patient's bone using the implant of claim 1.

18. 1. An implant for moving bone within a patient's body, said implant comprising: an implantable biocompatible housing having a first cavity; a first adjustment rod at least partially contained within the first cavity; a driver configured to drive the first adjustment rod to permit movement relative to the implantable biocompatible housing, the driver comprising: a magnetic actuator configured to be actuated by a magnetic field external to the patient's body; a driver including a driven gear system coupled to the magnetic actuator; a load sensor disposed between the driven gear system of the driver and the first adjustment rod, the load sensor indicating a load applied to the first adjustment rod by the driver.

19. 20. The implant of claim 18, wherein a load cell is configured to rotate with the driver relative to the implantable biocompatible housing.

20. 20. The implant of claim 18, wherein the load sensor comprises a bi-directional load sensor coupled to the driver and configured to indicate both a compressive load and a tensile load applied by the driver to the first adjustment rod.

21. 20. The implant of claim 18, wherein a proximal end of the first adjustment rod is configured to engage a lead screw and move with the lead screw.

22. 20. The implant of claim 18, wherein the implant is configured for intramedullary placement in a patient.

23. 20. The implant of claim 18, wherein the implant is configured to aid in the treatment of leg length inequality or bone defects within the patient.

24. 20. A method for intramedullary preparation of a patient's bone using the implant of claim 18.

25. 1. A method comprising: expanding the implanted distraction device using an external control device; measuring load sensor data using a load sensor of the implanted distraction device; and using the load sensor data to determine bone movement within the patient.

26. 26. The method of claim 25, wherein the load sensor enables determination of the amount of movement of a bone within the patient's body without imaging the bone within the patient's body.

27. The method of claim 25, wherein the external control device is positioned adjacent to the patient's body during expansion of the implanted distraction device.

28. The method of claim 25, wherein the external control device is remote from the patient's body during expansion of the implanted distraction device.

29. 26. The method of claim 25, wherein determining the amount of movement of the bone within the patient comprises converting the load sensor data into an estimated bone movement value.

30. 30. The method of claim 29, wherein the estimated bone movement value compensates for a margin of error.

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