Strut adjustment in a motorized bone fixation device

Abstract

In an external fixation device, adjustments in length (contracting or extending a strut) are carried out by respective motorized actuators of the struts, which are programmed to operate according to an actuation plan. In some embodiments, a total required change in length is defined for each of the struts, and based on the intended number of treatment days, a daily change in length is defined for the strut. Then, taking into account the number of intended device actuations per day, a change in length for each actuation is defined. Since the total required change in length may differ for different struts of the same device, the changes in length (whether at a single actuation or as a daily, cumulative change in length) can differ between the different struts.

Description

STRUT ADJUSTMENT IN A MOTORIZED BONE FIXATION DEVICE

[0001] The present application claims priority to, and the benefit of Israeli Patent Application No. 315319, entitled “STRUT ADJUSTMENT IN A MOTORIZED BONE FIXATION DEVICE,” which was filed on August 28, 2024, the entirety of which is expressly incorporated herein by reference.TECHNOLOGICAL FIELD

[0002] This invention relates to operation of an adjustable motorized bone fixation device, and more particularly to controlled movement of multiple struts of the bone fixation device.BACKGROUND

[0003] US11076801B2 to Cohen et al. discloses “An electrical circuitry fitted to be connected or to be an integral part of a bone fixation device having at least one linear actuator coupled between two rings, including: at least one linear actuator connector, mechanically and / or electrically connectable to said at least one linear actuator; a control circuitry, wherein said control circuitry measures a value related to the movement of said at least one linear actuator and / or to the distance or change in distance between said two rings, by receiving signals from said linear actuator connector; and a memory, wherein said memory stores said value.”GENERAL DESCRIPTION

[0004] A broad aspect of the present disclosure relates to length adjustments in struts of a motorized bone fixation device which can be custom-selected and set a high adjustment resolution of, for example, 0.01 mm or even 0.001 mm, in accordance with some embodiments.

[0005] In some embodiments, the adjustments in length (contracting or extending a strut) are carried out by respective motorized actuators of the struts, which are programmed to operate according to an actuation plan. In some embodiments, a total required change in length is defined for each of the struts, and based on the intended number of treatment days, a daily change in length is defined for the strut. Then, taking into account the number of intended device actuations perK710485 - OSP6010WOPCT1 day, a change in length for each actuation is defined. Since the total required change in length may differ for different struts of the same device, the changes in length (whether at a single actuation or as a daily, cumulative change in length) can differ between the different struts.

[0006] In some embodiments, the actuation plan is generated by (or for) the system and can take into account patient and / or physician preferences, such as the device operation hours over a day. Based on the device operation hours, a time interval between successive actuations can be set.

[0007] Due to the use of motorized actuation, which allows higher precision when controlling the strut length (e.g. as compared to manually adjusted struts), each adjustment step can be custom- selected, optionally individually per each of the multiple struts, and set as a rational number, including integers and fractions, for example from within the range of 0mm- 1 mm, or 0mm- 5 mm.

[0008] A potential advantage of methods and / or systems for example as described herein may include reducing or preventing pain to the patient, since the length change can be divided into more precise increments. This smoothens a slope of the change and allows for a more continuous, gradual adjustment. An optimized adjustment may be considered as one in which the cumulative adjustment, from an initial strut length to an end strut length, appears as a linear line.

[0009] Another potential advantage relates to the ability to individually define, for each of the multiple struts of the same device, its total change in length and / or its daily change in length and / or its change in length at every single actuation. In this manner, each strut is adjusted only as much as required, without an overshoot or undershoot.

[0010] As referred to herein, the term “adjustment” intends to cover a change in the length of a strut, which involves contracting or extending the strut axially. When the adjustment is carried out using an actuator of the strut, torque is generated by the actuator and translated (via gears, a lead screw coupled to the strut end, or as such) into shortening or lengthening of the strut.

[0011] As referred to herein, the system circuitry generally intends to cover memory components, control components (e.g. a processor), sw components or others which can be a part of the device itself (such as a part of the device control unit) or a part of an external or remote device such as a physician’s computer, a cellular phone, a patient’s personal computer, a hospital system, or other device being in communication with the device control unit.

[0012] In some cases, the circuitry (for example, using a software product on a remote device) is configured to receive or obtain input data which includes or is indicative of, for example, the intended number of treatment days, a total required change in strut length, the device operationalK710485 - OSP6010WOPCT1 hours and / or other data. Based on the received data, an actuation plan can be generated. The actuation plan can then be transmitted or otherwise saved to a control unit of the device itself.

[0013] It is noted that when quantitative values such as, for example, “intended number of treatment days”; “total required change in strut length”; “device operational hours” or other values are mentioned, these should also cover quantitative values which derive or are otherwise indicative of those values or associated with them.

[0014] Unless specifically stated otherwise, as apparent from the following discussions, it is appreciated that throughout the specification, discussions utilizing terms such as “executing”, “triggering”, “providing”, “detecting”, “determining”, “obtaining”, “adapting”, “switching”, “modifying”, “displaying”, “performing”, or the like, refer to the action(s) and / or process(es) of a computer that manipulate and / or transform data into other data, said data represented as physical, such as electronic, quantities and / or said data representing the physical objects.

[0015] The terms “computer”, “computerized device”, “control unit”, “controller” should be expansively construed to include any kind of hardware-based electronic device with a data processing circuitry (e.g., digital signal processor (DSP), a GPU, a TPU, a field programmable gate array (FPGA), an application specific integrated circuit (ASIC), microcontroller, microprocessor etc.). The data processing circuitry (designated hereinafter as processor and memory circuitry) can comprise, for example, one or more processors operatively connected to computer memory, loaded with executable instructions for executing operations.

[0016] Operations in accordance with the teachings herein may be performed by a computer or computerized device specially constructed for the desired purposes, or by a general -purpose computer or computerized device specially configured for the desired purpose by a computer program stored in a computer readable storage medium.Following is a non-exclusive list of some examples of the disclosure. The present disclosure also includes examples which include fewer than all the features in an example and examples using features from multiple examples, even if not listed below.Example 1A control system for use with an adjustable bone fixation device having a frame connectible to bone tissue and multiple struts connected to the frame, the control system comprising:K710485 - OSP6010WOPCT1 multiple actuators associated with the multiple struts, each actuator configured for adjusting a length of at least one strut; and circuitry configured to: obtain data indicative of an intended number of treatment days; for each of the multiple struts, a total required change in strut length; generate an actuation plan which defines for each of the multiple struts, a strut-specific daily change in length, the strut-specific daily change in length computed according to the obtained data; and generate a command instructing the multiple actuators to adjust the struts according to the actuation plan to thereby move the frame.Example 2The system according to Example 1, wherein the obtained data is indicative of an intended number of actuations per day, and wherein the actuation plan defines, for each of the multiple struts, a change in length to be obtained in every single actuation.Example 3The system according to Example 2, wherein the strut-specific daily change in length is computed by dividing the total required change in length by the intended number of treatment days; and the change in length to be obtained in every single actuation is computed by dividing the daily change in length by the intended number of actuations per day.Example 4The system according to any one of Examples 1-3, wherein the strut-specific daily change in length differs between at least two of the multiple struts, and therefore the daily change in length differs between said at least two struts.Example 5The system according to any one of Examples 2-4, wherein the obtained data is indicative of a range of device operational hours, and wherein the actuation plan defines a time interval betweenK710485 - OSP6010WOPCT1 successive actuations, the time interval computed by dividing the device operational hours by the intended number of actuations per day.Example 6The system according to Example 5, wherein an upper threshold and a lower threshold are set for the time interval between successive actuations; the upper threshold selected so as to reduce or prevent bone consolidation between successive actuations; and the lower threshold selected so as to prevent or reduce inconvenience to the patient.Example 7The system according to Example 5 or Example 6, wherein the range of device operational hours is personalized per the patient.Example 8The system according to any one of the preceding Examples, wherein the total required change in length for each of the multiple struts is a factor of an initial or current bone position, and a final desired bone position.Example 9The system according to any one of Examples 2-8, wherein the daily change in strut length and the change in length for a single actuation are both rational numbers selected from within the range of 0 mm and 5 mm.Example 10The system according to Example 9, wherein the daily change in strut length and the change in length for a single actuation are non-integers.Example 11The system according to any one of Examples 2-10, wherein the change in length for a single actuation is equal for all actuations of a single strut.K710485 - OSP6010WOPCT1Example 12The system according to any one of the preceding Examples, wherein the circuitry is configured to control one or both of: torque generated by each of the multiple actuators at each actuation, and a duration of each actuation to reach the computed change in strut length.Example 13The system according to any one of the preceding Examples, wherein the frame comprises at least two spaced apart portions which are connected to each other by the struts.Example 14The system according to Example 13, wherein the at least two spaced apart portions constitute two rings, and wherein adjustment of the strut lengths modifies a distance between the rings and thereby a position and / or orientation of the rings with respect to each other and / or with respect to bone tissue.Example 15A computer-implemented method for controlling adjustment of a bone fixation device having a frame connectible to bone tissue, multiple struts connected to the frame, and multiple actuators associated with the multiple struts, each actuator configured for adjusting a length of at least one strut; the method comprising: obtaining data indicative of: an intended number of treatment days; for each of the multiple struts, a total required change in strut length; generating an actuation plan which defines for each of the multiple struts, a strut-specific daily change in length, the strut-specific daily change in length computed according to the obtained data; and generating a command instructing multiple actuators of the bone fixation device to adjust the struts according to the actuation plan to thereby move the frame.K710485 - OSP6010WOPCT1Example 16The method according to Example 15, wherein the obtained data is indicative of an intended number of actuations per day, and wherein the actuation plan defines, for each of the multiple struts, a change in length to be obtained in every single actuation.Example 17The method according to Example 16, wherein the strut-specific daily change in length is computed by dividing the total required change in length by the intended number of treatment days; and the change in length to be obtained in every single actuation is computed by dividing the daily change in length by the intended number of actuations per day.Example 18The method according to Example 16 or Example 17, wherein the strut-specific daily change in length differs between at least two of the multiple struts, and therefore the daily change in length differs between said at least two struts.Example 19The method according to any one of Example 16-18, wherein the obtained data is indicative of a range of device operational hours, and wherein the actuation plan defines a time interval between successive actuations, the time interval computed by dividing the device operational hours by the intended number of actuations per day.Example 20The method according to any one of Examples 16-19, wherein the daily change in strut length and the change in length for a single actuation are both rational numbers selected from within the range of 0 mm and 5 mm.K710485 - OSP6010WOPCT1Example 21The method according to Example 20, wherein the daily change in strut length and the change in length for a single actuation are non-integers.Example 22The method according to any one of Example 16-21, wherein the change in length for a single actuation is equal for all actuations of a single strut.Example 23The method according to any one of Example 15-22, wherein generating a command further comprises instructing each of the multiple actuators to generate a selected torque and operate at a selected duration to reach the computed change in strut length.Example 24The method according to any one of Examples 15-23, wherein generating a command comprises instructing the actuators to contract or extend the respective strut axially.Example 25A computer-implemented method for controlling adjustment of a bone fixation device, the method comprising: obtaining data indicative of: an intended number of treatment days; for each of the multiple struts, a total required change in strut length; and an intended number of actuations per day; generating an actuation plan, wherein generating comprises: based on the obtained intended number of treatment days and the total required change in strut length, computing for each of the struts a daily change in length; based on the computed daily change in length and the intended number of actuations per day, computing a change in length to be obtained at a single actuation; and transmitting the actuation plan to a control unit of the bone fixation device.K710485 - OSP6010WOPCT1Example 26The method according to Example 25, wherein the obtained data is indicative of a daily range of device operational hours; and wherein generating the actuation plan comprises computing time intervals between successive actuations based on the intended number of actuations per day, and the daily range of device operational hours, in a manner which evenly distributes the daily change in length across the daily range of device operational hours.Example 27A computer-implemented method for controlling adjustment of a bone fixation device which comprises multiple struts, the method comprising: calculating or receiving as input a total required change in length for each of the multiple struts; based on an intended number of treatment days, calculating a daily change in length for each of the struts; based on an intended number actuations per day, calculating a change in length at a single actuation; wherein the change in length assigned to each strut at a single actuation is constant for a strut and can be different for different struts out of the multiple struts.Example 28The method according to Example 27, wherein for at least two struts out of the multiple struts, the length assigned to each strut at a single actuation is different.K710485 - OSP6010WOPCT1Example 29A bone fixation system comprising: a frame connectible to bone tissue; multiple struts connected to the frame; multiple actuators associated with the multiple struts, each actuator configured for adjusting a length of at least one strut; and circuitry configured to: obtain data indicative of: an intended number of treatment days; for each of the multiple struts, a total required change in strut length; generate an actuation plan which defines for each of the multiple struts, a strut-specific daily change in length, the strut-specific daily change in length computed according to the obtained data; and generate a command instructing the multiple actuators to adjust the struts according to the actuation plan to thereby move the frame.BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to better understand the subject matter that is disclosed herein and to exemplify how it may be carried out in practice, embodiments will now be described, by way of non-limiting examples only, with reference to the accompanying drawings, in which:

[0018] FIG. 1 illustrates an adjustable bone fixation device connected to a bone, according to embodiments of the presently disclosed subject matter;

[0019] FIG. 2 illustrates a control system for use with an adjustable bone fixation device, according to embodiments of the presently disclosed subject matter;

[0020] FIG. 3 is a block diagram of a control system for use with an adjustable bone fixation device, according to embodiments of the presently disclosed subject matter;

[0021] FIG. 4A is one example of a method for calculating an adjustment length of a strut, according to embodiments of the presently disclosed subject matter;

[0022] FIG. 4B is one example of a method of calculating a time interval between successive actuations for a specific patient, according to embodiments of the presently disclosed subjectK710485 - OSP6010WOPCT1 matter;

[0023] FIG. 5 is a table of an exemplary actuation plan, according to embodiments of the presently disclosed subject matter;

[0024] FIGS. 6A-B are a table and its graphic representation, showing an example single strut actuation plan employing binary length changes as compared to an actuation plan employing custom-selected length changes, according to embodiments of the presently disclosed subject matter;

[0025] FIG. 7 is a table comparing an actuation plan for multiple struts which employs binary length changes with an actuation plan for multiple struts which employs custom-selected length changes, according to embodiments of the presently disclosed subject matter;

[0026] FIG. 8 and FIG. 9 are two examples of actuation plans for multiple struts of the bone fixation device, according to embodiments of the presently disclosed subject matter.DETAILED DESCRIPTION OF EMBODIMENTS

[0027] FIG. 1 illustrates an adjustable bone fixation device connected to a bone, according to embodiments of the presently disclosed subject matter.

[0028] Bone fixation device 101 is generally intended to be connected to the bone of a patient, in a surgical process. In some cases, the device is used for the treatment of a fractured bone, misaligned bone(s), a deformed bone, a bone that needs to be changed in length, and / or other orthopedic or generally bone related conditions.

[0029] The bone fixation device is generally comprised of a frame constituting of at least two portions, 103 and 105, and a plurality of struts 107 (e.g. 1, 2, 4, 5, 8, 10 or intermediate or larger number of struts), connecting the at least two portions of the frame. In some embodiments, as shown, the bone fixation device is shaped as a hexapod, and the two frame portions are formed as two rings having six struts which interconnect the rings. In other embodiments, the two frame portions may include open rings, arc shaped frames, horseshoe shaped frames, rods, and / or otherwise shaped frame portions.

[0030] In some embodiments, the two portions of the frame are at least partially connected to the bone via pins (e.g. transfixation pins), rods, wires (e.g. k-wires), or other suitable fixation elements which extend from the frame portion and into the bone. Adjustment of the struts, such as by lengthening or shortening a strut along a linear axis, modifies a distance between the two frameK710485 - OSP6010WOPCT1 portions (e.g. by pulling on the frame portions towards each other or by pushing the frame portions away from each other). In an example, shortening of struts can approximate the two frame portions towards each other; lengthening of struts can distance the two frame portions away from each other. Adjustment of the struts can also modify the relative position and / or orientation of the two frame portions (and the bone portions to which the frame portions are attached) with respect to each other, for example, shortening of some of the struts and / or lengthening of some of the struts can change an angular orientation of the frame portions with respect to each other (for example, when the frame portions consist of rings, move the ring to change a planar layout thereof)).

[0031] Automated adjustment of the bone fixation device is carried out, in accordance with some embodiments, by a control system which is operably connected to the device. The control system is generally comprised of a control unit 109 and a plurality of actuators 111, such as motors (e.g. linear motors). In some embodiments, each of the actuators is associated with a single strut and is configured to drive the adjustment of the specific strut. In some embodiments, the control unit is electrically connected to the actuators via cables 113. Additionally or alternatively, a wireless connection may be established between the control unit and the actuators.

[0032] In some embodiments, each of the actuators is maintained within a designated adaptor 115 which holds the actuator in an operable coupling with the strut. In some embodiments, the adaptor is shaped to maintain the actuator axially aligned with the strut which the actuator adjusts. Alternatively, in some embodiments, an actuator may be contained (e.g. embedded) within the strut itself.

[0033] In some embodiments, the control system of the bone fixation device comprises one or more sensors, for example: sensors configured for obtaining system related measurements, such as for measuring operational parameters of the actuators (e.g. torque generated by an actuator, current consumption, operation voltage, rotation speed of the actuator, etc.); and / or sensors configured for obtaining measurements related to the surroundings, such as for measuring environmental conditions (e.g. temperature, humidity), measuring a load or impact on the device, measuring a posture of the patient, etc. FIG.l shows an example of a sensor 117 for measuring load acting on the device, positioned, for example, at an attachment area of a strut to the top frame portion.

[0034] It is noted that while a hexapod external fixation device is shown herein, other bone fixation devices such as a mono-rail are also contemplated.K710485 - OSP6010WOPCT1

[0035] FIG. 2 illustrates a control system for use with an adjustable bone fixation device, according to embodiments of the presently disclosed subject matter.

[0036] A control system 200 as shown generally comprises a control unit 201, comprising a housing in which computational, processing, communication and / or memory means are contained. The control unit is operably connected to a plurality of actuators 203, optionally, via cables 205 or other suitable wiring. In some embodiments, each of the actuators is comprised of a motor, for example, a brush DC motor or a brushless DC motor.

[0037] In some embodiments, control unit 201 comprises a power source (not shown), for example an electric power source. In some embodiments, the power source comprises a battery, for example a non-replaceable battery or a replaceable battery or a rechargeable battery. In some embodiments, the control unit delivers electric power from the power source to each of the actuators via the cables. Optionally, the battery is sufficient to power the device for as long as the bone fixation device is required to stay connected to the bone, for example, for a time period of between 1-3 months.

[0038] In some embodiments, in use, the control system is coupled to the frame and the struts of the bone fixation device. In some embodiments, each actuator is operably connected to a strut such that activation of the actuator generates torque for adjusting the strut. In an example, the actuator rotates a gear or a gear train which is operably coupled to at its end to a threaded lead screw. Movement of the lead screw linearly shortens or lengthens the strut by extending or contracting an adjustable segment of the strut. It is noted that other mechanisms may be used for adjusting the strut, for example, a hydraulic mechanism, a spring-based mechanism, a magnetic mechanism, and / or other mechanism suitable for extending or contracting an adjustable segment of the strut.

[0039] In embodiments in which the actuator is external to the strut, the actuator may be held by an adaptor or other suitable restraining means for coupling the actuator to the struts. In embodiments in which the actuator is embedded within the strut, a connector may be used for connecting the control unit (such as via the cables or other wiring) to the embedded actuator.

[0040] In some embodiments, the control unit housing is removably connected to the frame, for example via fasteners.

[0041] In some embodiments, an actuation plan is uploaded (or otherwise communicated) to the control unit, in which it can be stored (for example, in a memory of the control unit). Optionally, an actuation plan is communicated to the control unit over the network.K710485 - OSP6010WOPCT1

[0042] The actuation plan is designed to carry out a treatment regimen, which can be determined based on a diagnosis of the patient (for example, using the results of tissue imaging); based on patient parameters (e.g. age, level of physical activity); based on the required bone modification; and / or other factors.

[0043] In some embodiments, the actuation plan sets parameters according to which the control system operates the actuators. The parameters can be set for each actuator separately, or for multiple actuators together. The parameters can be set per a single actuation session, or per multiple actuation sessions together. For each of the parameters, an upper limit and / or a lower limit can be calculated (or otherwise inputted), for example for ensuring safe operation of the device. Parameters set by the actuation plan can include: a. Time related parameters, such as: a total treatment period (e.g. 1 week, 6 weeks, 1 months, 3 months); daily operational hours for the device; total number of device actuations per day; time intervals between subsequent actuations; an actuation duration; and / or other related parameters, which will be discussed in more details below; b. A torque range or limit to be generated by an actuator in an actuation; and / or other operational parameters of the actuator which affect, directly or indirectly, the adjustment of the strut, such as: current consumption of the actuator, voltage, rotation speed of the actuator, or other. c. Desired changes in the length of a strut, as further detailed below.

[0044] FIG. 3 is a block diagram of a control system for use with an adjustable bone fixation device, according to embodiments of the presently disclosed subject matter.

[0045] As described hereinabove, in some embodiments, control system 301 includes a control unit 303 for controlling the plurality of actuators 305. In some embodiments, the control unit operates the actuators according to an actuation plan stored at a memory 307 of the control unit.

[0046] In some embodiments, control unit 303 is configured to obtain readings from one or more sensors 309 of the system. In some embodiments, the sensors 309 include one or more sensors 310 that are configured for measuring system- related parameters, such as actuator-related parameters, for example, measure the torque generated by the actuator which is indicative of the axial force applied onto the strut. In some cases, one or more sensors are configured for measuring the torque and / or a parameter indicative of the torque, for example, for measuring the current consumption of the actuator (e.g. a current meter or sensor). Since in some embodiments the actuator is configured to directly drive the adjustment of the strut, a correlation exists between consumptionK710485 - OSP6010WOPCT1 of electrical current by the actuator and the torque generated the actuator (e.g. when brushed motors are used), and / or between the rotation speed of the actuator and voltage, and the torque generated by the actuator (e.g. when brushless motors are used).

[0047] In some embodiments, sensors 309 include one or more sensors 312 that are configured for measuring conditions related to the surroundings of the device, and / or to external factors which may have an effect on device operation. Examples of such sensors include: a temperature sensor and / or a humidity sensor, since, for example, extreme temperature conditions may affect operation of the actuator and / or of the circuitry; a sensor configured for detecting the current posture of the patient, since, for example, in a patient standing up the load acting on the device would be higher as compared to when the patient sits or lies down; a sensor configured for detecting a current orientation of the body part to which the device is connected, since, for example strut adjustment and / or actuator operation may be affected by the orientation and / or the load acting on the device in a certain orientation; an acceleration sensor or an impact sensor, since, for example, it would be preferred to adjust the strut whilst the patient is still and not moving; a weight / load sensor.

[0048] Referring back to the block diagram, in some embodiments, the system includes a timer and / or a clock 311, which can be utilized by the control unit for timing operation of the actuators according to the actuation plan; for monitoring a duration of actuation and / or monitoring the time it takes to complete a planned adjustment of a strut; monitoring a time interval between successive actuations; complying with selected operational hours of the device; and / or other time or timing related factors.

[0049] In some embodiments, each of the actuators is coupled to an encoder 313, which is in communication with the control unit. The encoder tracks the speed and / or position of the moving part (e.g. shaft, rotor) of the actuator. Based on the feedback received from the encoder, control unit 303 can determine the change in the length of the strut, and / or a relative position of the strut, and / or a speed in which the strut is adjusted.

[0050] In some embodiments, based on input received from the sensors, the clock / timer, and / or the encoder(s), the control unit is configured to determine the extent of adjustment and to identify whether the adjustment had been carried out according to the actuation plan.

[0051] In some embodiments, one or more components of the control system 301, for example the control unit 303, are in communication with a remote or external device 315. The remote device may include a cellular phone, a wearable device, a remote computer, a tablet, a remote server, anK710485 - OSP6010WOPCT1 information storage cloud. In some cases, the control system communicates with a remote device of the patient or a caregiver, a physician, or other.

[0052] FIG. 4A is an example of a method for calculating an adjustment length of a strut, according to embodiments of the presently disclosed subject matter.

[0053] At 401, for each of the multiple struts of the device, a total required change in length is defined. In some embodiments, the total required change in length is the delta between an initial length of a strut and a final desired length of the strut, as measured for example at the end of the treatment period. As the strut extends between the two rings of the device, any change in strut length is associated with a change in a distance between the rings and / or a change in an orientation (e.g. a planar layout) of the rings. In some cases, the total required change in length is calculated or otherwise deduced by the system circuitry (for example, using dedicated software, such as at a physician’s computer). The total required change in length can be determined based on data entered by the physician, based on analysis of images (e.g. X-ray images) of the treated bone(s), based on data defined in literature, based on a visual inspection of the device, based on the patient’ s clinical condition and / or other sources. In some embodiments, the total required change length is strut-specific, that is, the total required change in length can differ for different struts of the same device. This can occur, for example, when the two rings lie in planes that are not parallel to each other (at least at their initial alignment, following the surgical procedure), resulting in a combination of longer struts and shorter struts.

[0054] At 403, a calculation is performed by the circuitry, in which the total required change in length is divided by an intended number of treatment days, to reach the daily change in length. At 405, the calculation continues by dividing the daily change in length by the intended number of actuations per day, to reach the change in length for a single actuation.

[0055] Since the total required change in length can differ for different struts, the resulting change in length for every actuation would also differ for different struts, requiring adaptations, for example, in actuator operation, such as the torque generated by the actuator and / or the actuation duration. Optionally, a similar duration is set for the multiple actuators (e.g. for every actuation), but the torque is adjusted so that each strut will be modified (extended or contracted) so as to reach its specific required change in length. Alternatively, a similar torque level can be set for the multiple actuators, but the actuation duration would differ.

[0056] FIG. 4B is an example of a method of calculating a time interval between successiveK710485 - OSP6010WOPCT1 actuations for a specific patient, according to embodiments of the presently disclosed subject matter.

[0057] At 411, a range of device operational hours over a day is selected. Optionally, the operational hours are personalized per the patient, and can be selected taking into account patient preferences. Commonly, the device operational hours are during the patient’s waking hours, so that when the patient sleeps, they are not interrupted by the movement. For determining a time between successive actuations, at 413, the device operational hours are divided by the intended number of actuations per day.

[0058] With regards to the above-described schemes, it is generally preferred to divide the daily required change in length to as many actuations as possible, thereby reducing the length change required at each actuation and potentially preventing or reducing pain to the patient. By that, a slope of the change is set to a minimum possible, and the strut adjustment graph is “smoothened”. While from a clinical perspective, continuous adjustment can be advantageous, e.g. for improving bone generation, from practical aspects such as the system energy consumption and the patient’s daily routine, dividing the daily required change in length into up to 20 actuations per day, up to 50 actuations per day, up to 100 actuations per day or intermediate, higher or lower number of actuations may be preferrable.

[0059] In some cases, the time interval between successive actuations is selected from a range having an upper threshold and a lower threshold. The upper threshold can be selected to reduce or prevent a risk of the bone consolidating before its full desired movement (alignment) had been reached. In other words, if a too long time period passes between successive actuations, the bone may start to consolidate, requiring a higher force to be applied for adjusting the struts to move the rings. The lower threshold for the time interval can be selected so as to enable a minimal interval between successive actuations, for example taking into consideration the system’s energy consumption limitations and / or the patient’s daily routine, as noted above.

[0060] It is noted that the methods described in FIGS. 4A-B are examples of calculations which can be performed for determining a strut-specific daily length change and / or a strut specific length change at each actuation; these values may be reached by other calculation methods and / or using input other than indicated. For example, a desired rate of treatment (e.g., change in length per a day, per a week, per a month or other time period) may be inputted, along with a total required change in length for each strut, and the system will calculate the intended number of treatmentdays accordingly.

[0061] FIG. 5 is a table of an exemplary actuation plan, according to embodiments of the presently disclosed subject matter.

[0062] As shown, each of the 6 struts of the device (in this example; generally, the number of struts can be 2, 3, 4, 5, 7, 8, 10, or intermediate or higher number of struts) has its own required total change in length. (For some of the struts this length can be equal, and for others to differ). Since the number of treatment days and the number of actuations per day is identical for all struts, each of the struts has its own daily change in length, and therefore, its specific required single actuation length. As shown, this resulting length can be a rational number, for example between 0.01 and 1 mm; it does not have to be an integer but can also be a fractional / decimal number.

[0063] Generally, operation of the device actuators is programmed according to the actuation plan to carry out such specific, high-resolution changes in strut lengths. This is potentially advantageous over, for example, manually adjusted bone fixation devices which are commonly limited to gross adjustment, e.g., of about 1 mm at each manual actuation. In manually adjusted devices, the patient and / or caregiver manually adjust the strut while they also need to determine the carried out change in length, for example using a ruler embedded on the strut. Since the change in length has to be identifiable by a human user, it cannot be very small, for example, it cannot be less than 1 mm. The described motorized device, on the other hand, can automatically carry out very small length adjustments and control the extent of movement.

[0064] In some cases, an actuation plan for a specific patient is generated (e.g., using dedicated software). The plan can be generated on a remote device, e.g., on a physician’s computer, and then uploaded or otherwise communicated to the control unit of the device.

[0065] In some cases, patient preferences and / or physician’s preferences are received as input and are taken into account when generating the actuation plan. Examples of such preferences include: preferred device operational hours (e.g., only during waking hours of the patient); other patient schedule considerations; patient condition considerations (e.g., related to age, gender, health condition, physical status); treatment rate considerations (e.g., the physician instructs to maximize the daily change in length to carry out the treatment faster); and even expected pain tolerance, based on which it can be determined if to make less actuations with a higher strut adjustment length in each (if the patient has a high pain tolerance); or more actuations with a shorter strut adjustment length in each (if the patient has a high pain tolerance).K710485 - OSP6010WOPCT1

[0066] FIGs. 6A-B are a table and its graphic representation, showing an example single strut actuation plan employing binary length changes as compared to an actuation plan employing custom-selected length changes, according to embodiments of the presently disclosed subject matter.

[0067] In the example shown, a total required change in length for the strut is 7.5 mm, to be obtained over a treatment period of 10 days. This implies an optimal slope (cumulative length change / number of days that passed) of 0.75.

[0068] It can be observed that when adjusting the strut in binary steps, of either 0 mm a day or 1 mm a day (the top half of the table), there is a difference between the resulting slope and the optimal slope, which is indicated by the error percentage. On the contrary, when adjusting the strut in custom-selected steps (the bottom half of the table), the optimal slope can be reached. This is enabled due to the ability to set the length changes at a high resolution, in this example, a resolution of 0.01 mm.

[0069] The graph of FIG. 6B demonstrates the cumulative length changes over time when using the binary length changes and the custom selected length changes referred to above.

[0070] FIG. 7 is a table comparing an actuation plan for multiple struts which employs binary length changes with an actuation plan for multiple struts which employs custom-selected length changes, according to embodiments of the presently disclosed subject matter.

[0071] As can be observed, by employing the custom-selected lengths, an optimized slope can be reached for each of the multiple (in this example, 6) struts, as compared to when binary lengths are employed. When using custom-selected lengths, a daily length change can be selected, for example, from within the range of 0.01 mm to 1 mm. Each of the struts can have its own (“strutspecific”) change in length, as calculated for example according to figures 4A-B above.

[0072] FIG. 8 and FIG. 9 are two examples of actuation plans for multiple struts of the bone fixation device, according to some embodiments.

[0073] The graph of FIG. 8 shows length adjustment in 6 struts, carried out over the course of two days. In the example shown, length adjustments are performed during day hours, while at night the length remains constant. As can be further observed, each strut is adjusted at a different rate, i.e. having its own “strut-specific” change in length for a single actuation. As a result, it can be seen in this example that strut number 1 had the most significant total increase in length; while strut number 6 had the lowest total increase in its length. (It is noted that in this example all strutsK710485 - OSP6010WOPCT1 were extended, however, in other cases one or more struts may be contracted and shortened in length.) In the table of FIG. 9, a cumulative length of each of 5 struts is indicated with respect to the time of day in which the actuations are performed. In this example, similar to the example of FIG. 8, actuations are performed only during day hours, e.g. between 8:00-18:00. During each day, 10 actuations are performed, with a time interval of 1 hour between them, as can be further observed, each strut has its own “strut-specific” change in length at a single actuation: strut A is adjusted by 0.5 mm at every actuation; strut B is adjusted by 0.4mm at every actuation; strut C is adjusted by 0.7 mm at every actuation; strut D is adjusted by 0.2 mm at every actuation; strut E is adjusted by 0.1 mm at every actuation.7

Claims

What Is Claimed Is:

1. A control system for use with an adjustable bone fixation device having a frame connectible to bone tissue and multiple struts connected to the frame, the control system comprising: multiple actuators associated with the multiple struts, each actuator configured for adjusting a length of at least one strut; and circuitry configured to: obtain data indicative of: an intended number of treatment days; for each of the multiple struts, a total required change in strut length; generate an actuation plan which defines for each of the multiple struts, a strut-specific daily change in length, the strut-specific daily change in length computed according to the obtained data; and generate a command instructing the multiple actuators to adjust the struts according to the actuation plan to thereby move the frame.

2. The system according to claim 1, wherein the obtained data is indicative of an intended number of actuations per day, and wherein the actuation plan defines, for each of the multiple struts, a change in length to be obtained in every single actuation.

3. The system according to claim 2, wherein the strut-specific daily change in length is computed by dividing the total required change in length by the intended number of treatment days; and the change in length to be obtained in every single actuation is computed by dividing the daily change in length by the intended number of actuations per day.

4. The system according to any one of claims 1-3, wherein the strut-specific daily change in length differs between at least two of the multiple struts, and therefore the daily change in length differs between said at least two struts.K7 10485 - OSP6010WOPCT15. The system according to any one of claims 2-4, wherein the obtained data is indicative of a range of device operational hours, and wherein the actuation plan defines a time interval between successive actuations, the time interval computed by dividing the device operational hours by the intended number of actuations per day.

6. The system according to claim 5, wherein an upper threshold and a lower threshold are set for the time interval between successive actuations; the upper threshold selected so as to reduce or prevent bone consolidation between successive actuations; and the lower threshold selected so as to prevent or reduce inconvenience to the patient.

7. The system according to claim 5 or claim 6, wherein the range of device operational hours is personalized per the patient.

8. The system according to any one of the preceding claims, wherein the total required change in length for each of the multiple struts is a factor of an initial or current bone position, and a final desired bone position.

9. The system according to any one of claims 2-8, wherein the daily change in strut length and the change in length for a single actuation are both rational numbers selected from within the range of 0 mm and 5 mm.

10. The system according to claim 9, wherein the daily change in strut length and the change in length for a single actuation are non-integers.

11. The system according to any one of claims 2-10, wherein the change in length for a single actuation is equal for all actuations of a single strut.

12. The system according to any one of the preceding claims, wherein the circuitry is configured to control one or both of: torque generated by each of the multiple actuators atK710485 - OSP6010WOPCT1 each actuation, and a duration of each actuation to reach the computed change in strut length.

13. The system according to any one of the preceding claims, wherein the frame comprises at least two spaced apart portions which are connected to each other by the struts.

14. The system according to claim 13, wherein the at least two spaced apart portions constitute two rings, and wherein adjustment of the strut lengths modifies a distance between the rings and thereby a position and / or orientation of the rings with respect to each other and / or with respect to bone tissue.

15. A computer-implemented method for controlling adjustment of a bone fixation device having a frame connectible to bone tissue, multiple struts connected to the frame, and multiple actuators associated with the multiple struts, each actuator configured for adjusting a length of at least one strut; the method comprising: obtaining data indicative of: an intended number of treatment days; for each of the multiple struts, a total required change in strut length; generating an actuation plan which defines for each of the multiple struts, a strut-specific daily change in length, the strut-specific daily change in length computed according to the obtained data; and generating a command instructing multiple actuators of the bone fixation device to adjust the struts according to the actuation plan to thereby move the frame.

16. The method according to claim 15, wherein the obtained data is indicative of an intended number of actuations per day, and wherein the actuation plan defines, for each of the multiple struts, a change in length to be obtained in every single actuation.

17. The method according to claim 16, wherein the strut-specific daily change in length is computed by dividing the total required change in length by the intended number of treatment days; and the change in length to be obtained in every single actuation isK7 10485 - OSP6010WOPCT1 computed by dividing the daily change in length by the intended number of actuations per day.

18. The method according to claim 16 or claim 17, wherein the strut-specific daily change in length differs between at least two of the multiple struts, and therefore the daily change in length differs between said at least two struts.

19. The method according to any one of claims 16-18, wherein the obtained data is indicative of a range of device operational hours, and wherein the actuation plan defines a time interval between successive actuations, the time interval computed by dividing the device operational hours by the intended number of actuations per day.

20. The method according to any one of claims 16-19, wherein the daily change in strut length and the change in length for a single actuation are both rational numbers selected from within the range of 0 mm and 5 mm.

21. The method according to claim 20, wherein the daily change in strut length and the change in length for a single actuation are non-integers.

22. The method according to any one of claims 16-21, wherein the change in length for a single actuation is equal for all actuations of a single strut.

23. The method according to any one of claims 15-22, wherein generating a command further comprises instructing each of the multiple actuators to generate a selected torque and operate at a selected duration to reach the computed change in strut length.

24. The method according to any one of claims 15-23, wherein generating a command comprises instructing the actuators to contract or extend the respective strut axially.

25. A computer-implemented method for controlling adjustment of a bone fixation device, the method comprising:obtaining data indicative of: an intended number of treatment days; for each of the multiple struts, a total required change in strut length; and an intended number of actuations per day; generating an actuation plan, wherein generating comprises: based on the obtained intended number of treatment days and the total required change in strut length, computing for each of the struts a daily change in length; based on the computed daily change in length and the intended number of actuations per day, computing a change in length to be obtained at a single actuation; and transmitting the actuation plan to a control unit of the bone fixation device.

26. The method according to claim 25, wherein the obtained data is indicative of a daily range of device operational hours; and wherein generating the actuation plan comprises computing time intervals between successive actuations based on the intended number of actuations per day, and the daily range of device operational hours, in a manner which evenly distributes the daily change in length across the daily range of device operational hours.

27. A computer-implemented method for controlling adjustment of a bone fixation device which comprises multiple struts, the method comprising: calculating or receiving as input a total required change in length for each of the multiple struts; based on an intended number of treatment days, calculating a daily change in length for each of the struts; based on an intended number of actuations per day, calculating a change in length at a single actuation; wherein the change in length assigned to each strut at a single actuation is constant for a strut and can be different for different struts out of the multiple struts.

28. The method according to claim 27, wherein for at least two struts out of the multiple struts, the length assigned to each strut at a single actuation is different.K7 10485 - OSP6010WOPCT129. A bone fixation system comprising: a frame connectible to bone tissue; multiple struts connected to the frame; multiple actuators associated with the multiple struts, each actuator configured for adjusting a length of at least one strut; and circuitry configured to: obtain data indicative of: an intended number of treatment days; for each of the multiple struts, a total required change in strut length; generate an actuation plan which defines for each of the multiple struts, a strut-specific daily change in length, the strut-specific daily change in length computed according to the obtained data; and generate a command instructing the multiple actuators to adjust the struts according to the actuation plan to thereby move the frame.

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