Continuous power delivery and monitoring system for implantable devices

Abstract

The present disclosure provides a continuous power delivery system for implantable devices, including: a wearable device configured to be worn on a patient's body, the wearable device configured to communicate with a power transmitter and receive a first power signal via a first communication protocol, the wearable device including battery management circuitry to a control a charging of a battery using the first power signal and to control a discharge of the battery to generate a second power signal; the wearable device further configured to communicate the second power signal via a second communications and powering protocol; and an implant device configured to be implanted in the patient's body, the implant device configured to communicate with the wearable device and receive the second power signal via the second communications and powering protocol, the implant device include one or more implant components configured to be powered by the second power signal.

Description

Docket No.: UA22-173PCT CONTINUOUS POWER DELIVERY AND MONITORING SYSTEM FOR IMPLANTABLE DEVICES CROSS-REFERENCE TO RELATED APPLICATION

[0001] The present application claims the benefit of U.S. Provisional Application Serial No. 63 / 525,625 filed 07-Jul-2023, which is hereby incorporated by reference in its entirety. TECHNICAL FIELD

[0002] The present disclosure is generally directed to a continuous power delivery system for implantable devices, and more particularly, to a continuous power delivery and data a monitoring system for subcutaneously implantable devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0003] Features and advantages of various embodiments of the claimed subject matter will become apparent as the following Detailed Description proceeds, and upon reference to the Drawings, wherein like numerals designate like parts, and in which:

[0004] FIG. 1 illustrates an example continuous power delivery and data monitoring system for subcutaneously implantable devices according to several embodiments of the present disclosure;

[0005] FIG. 2 illustrates an example embodiment of the continuous power delivery and data monitoring system described herein;

[0006] FIGS.3A-3D illustrate various views of a continuous power delivery and data monitoring system according to one embodiment of the present disclosure;

[0007] FIGS.4A-4C illustrate various aspects of long-term human trials of the continuous power delivery and data monitoring system according to embodiments described herein;

[0008] FIGS.5A-5F illustrate a continuous power delivery and data monitoring system according to one embodiment;

[0009] FIGS. 6A-6E illustrate various aspects of a large animal model of the continuous power delivery and data monitoring system according to one embodiment; andDocket No.: UA22-173PCT

[0010] FIGS.7A-7F illustrate long-term results of the large animal study of the continuous power delivery and data monitoring system of FIGS.5 and 6.

[0011] Although the following Detailed Description will proceed with reference being made to illustrative embodiments, many alternatives, modifications and variations thereof will be apparent to those skilled in the art. DETAILED DESCRIPTION

[0012] Continuous collection of biosignals offers profound benefits in refining diagnostic accuracy, personalizing patient care, and assessing disease progression and intervention efficacy. However, unless patients are forced to remain stationary, continuous data collection over days to weeks relies on energy efficient battery-powered sensors and wearable devices. High data sampling rate is a major contributor to battery drain, restricting wireless applications which require increased sampling rates, such as continuous monitoring of the brain and nervous system, to shorter durations. Long-term sampling, even at the obligated low sampling rates, eventually requires removal and recharging of the battery-powered devices, forcing either the patient to remain stationary or causing a loss of data during these time periods. Current high speed data recording applications utilize large, bulky battery packs or tethered systems to meet power demands for reasonable time lengths. Limits on power storage are further exacerbated when working with implantable sensing systems, as they usually contain small electrochemical power supplies which cannot be charged or replaced without invasive surgical procedures.

[0013] Recent work with implantable medical devices has shown the advantages of devices which can be powered entirely through wireless power transfer (WPT) techniques, such as inductive coupling or piezoelectric ultrasonic energy harvesters. These wireless devices demonstrate increased functional lifetimes relative to electrochemical-driven implants as they do not require batteries, which must be recharged or replaced, and have been shown to perform tasks which require higher power consumption, such as electrical recording of peripheral nervous system or pacing for the heart. Additionally, they offer dramatically reduced displacement volumes that facilitate less invasive implant methods and better chronic stability with lower tissue irritation. Still, continuous operation of these devices is reliant upon an external power casting source, whichDocket No.: UA22-173PCT faces the limitations of portability, system bulk, power storage capacity, and the added transfer efficiency loss inherent to WPT.

[0014] The present disclosure provides a system that includes a continuously operating, wireless, wearable biosymbiotic device for powering and communicating with, for example, Near Field Communication (NFC)-capable implantable devices. This wearable device contains a small power storage which is recharged through far-field wireless power transfer, enabling continuous operation without the need to remove or connect the device for charging. By integrating with a wearable with at distance wireless recharging capabilities and outfit the biosymbiotic mesh with near field power and data transfer capabilities, we demonstrate a first-of-its-kind wearable implant interface for long-term continuous data aggregation from implantable devices, with no interaction required from the wearer. The wearable device can energize and establish bidirectional communication with any NFC-capable device implanted up to several centimeters deep. Through human experiments, the teachings of the present disclosure demonstrate continuous seven-day operation without any changes in habit or routines of the wearers. In large animal experiments, the teachings of the present disclosure show the feasibility of long-term bone health monitoring when paired with a fully-implantable, wireless, battery-free bone strain sensor. The system has broad applications for patient monitoring, from post-surgical recovery monitoring to assessment of therapeutic interventions, and as a sensing and stimulation interface for long-term disease management.

[0015] Accordingly, the present disclosure provides a continuous power delivery and data monitoring system for subcutaneously implantable devices. The system includes an implant device that includes communications circuitry for implantation into a patient. The system also includes a wearable device configured with power management circuitry, a rechargeable battery, and communications circuitry to wirelessly transmit power to the implant device. The system also includes power transmitter circuitry to communicate with the wearable device to wirelessly deliver power to the wearable device to charge the rechargeable battery of the wearable device. Communication between the implant and the wearable device may comply with, for example, known and / or proprietary near-field communications protocols. Communication between the wearable device and the power transmitter circuitry may comply with, for example, known and / or proprietary far-field communications protocols. In some embodiments, the wearable device may include memory to store data associated with the implant device, and may also include additionalDocket No.: UA22-173PCT communications circuitry to exchange commands and data with, for example, a patient monitoring database for long-term collection of patient data.

[0016] FIG. 1 illustrates an example continuous power delivery and data monitoring system 100 for subcutaneously implantable devices, according to several embodiments of the present disclosure. Generally, the system 100 includes power transmitter circuitry 102 configured to wirelessly transmit power to a wearable device 104, and the wearable device 104 is generally configured to wirelessly transmit power to a subdermal implant device 106. In some embodiments, the power transmitter circuitry 102 is configured to generate power and to transmit power, via far- field control circuitry 103, using a known and / or proprietary far-field power communications protocol, for example, Wireless Power Transfer (WPT), Wireless Energy Harvesting (WEH), etc. The power transmitter circuitry 102 may include a far-field antenna 108 to transmit power. The antenna 108 may include, for example, known and / or proprietary antenna designs, for example, known and / or proprietary antenna designs such as a dipole antenna, trace antenna, monopole antenna, etc., and power may be transmitted, via antenna 108 at a selected frequency to optimize power transfer, for example, 915 MHz, etc. In some embodiment, the power transmitter circuitry 102 is configured to transmit power at a range of, for example, several meters. The power transmitter circuitry 102 may be embodied as a desktop device, bed side device, automobile device, etc., such that when a patient is within range, power can be transmitted to the wearable device 104, as described below.

[0017] The wearable device 104 includes a far-field antenna 110 to communicate with and receive power from the power transmitter 102. The antenna 110 may be matched or tuned to antenna 108, and may include, for example, known and / or proprietary antenna designs, for example, known and / or proprietary antenna designs such as a dipole antenna, trace antenna, monopole antenna, etc., and power may be transmitted, via antenna 108 at a selected frequency to optimize power transfer, for example, 915 MHz, etc. The wearable device 104 also includes battery management circuitry 112 generally configured to provide controllable charging and discharging of a rechargeable battery 114. The battery 114 may include, for example, lithium ion (LiIon) type rechargeable battery configured to be recharged by transmitted power from the power transmitter 102.

[0018] The wearable device 104 also includes near field communications (NFC) control and powering circuitry 118 generally configured to exchange commands and data with the implant device 106, and to provide power delivery to the implant device 106. The wearable device 104Docket No.: UA22-173PCT also includes an NFC antenna 120. The antenna 120 may include, for example, known and / or proprietary antenna designs, for example, known and / or proprietary antenna designs such as a 3D printed antenna with ferrite core antenna, trace antenna, coil antenna, etc., and power may be transmitted, via antenna 108 at a selected frequency to optimize power transfer, for example, 13.56 MHz, etc. In some embodiment, the wearable device 104 is configured to transmit power at a range of, for example, several centimeters.

[0019] The implant device 106 includes an NFC antenna 122 to communicate with and receive power from the wearable device 104. The antenna 122 may be matched or tuned to antenna 120, and may include, for example, known and / or proprietary antenna designs, for example, known and / or proprietary antenna designs such as 3D printable antenna with ferrite core antenna, trace antenna, coil antenna, etc., and the implant device 106 may exchange commands and data with the wearable device 104 and receive power transmitted by the wearable device 104, via antenna 122 at a selected frequency to optimize power transfer, for example, 13.56 MHz, etc.

[0020] The implant device 106 also includes near field communications (NFC) control circuitry 118 generally configured to exchange commands and data with the implant device 106, and to control power delivery to the implant device 106 by coordinating with NFC control circuitry 118 of the wearable device 104. The implant device 106 also includes one or more implant component(s) 126 generally configured to provide a desired operability of the implant device 106 when subdermally implanted in a patient. The one or more implant component(s) 126 may include, for example, one or more sensors (e.g., temperature sensors, strain sensors, fluid sensors, etc.), one or more light activation devices (e.g., optegenetic stimulation circuitry, light emitting diode (LED) circuitry, etc.), etc., and / or other implant devices that provide for continuous data monitoring and / or therapeutic functionality. Advantageously, the implant component(s) 126 may be continuously powered by the NFC power delivery from the wearable device 104, and may also deliver data from the implant component(s) 126 (e.g., temperature data, strain data, fluid flow data, activation data, etc.) to the wearable device 104 for continuous patient monitoring.

[0021] In some embodiments, the wearable device 106 may also include communications circuitry 116 to exchange commands and data between the wearable device 104 and a patient database 134, via network 130. The communications circuitry 116 may comply or be compatible with, for example, Bluetooth short-range wireless communication, WiFi, and / or other know and / or proprietary communications protocols. The wearable device 104 may also include memoryDocket No.: UA22-173PCT circuitry 128 to store data parameters generated by the implant component(s) 126. The patient database 134 may provide remote access to patient data (generated by the implant device 106) by a doctor or clinician.

[0022] The patient database 134 may include wearable control circuitry 136 to provide administrative and operational control of the wearable device 104. For example, the wearable control circuitry 136 may communicate with the wearable device 104, via network 130, to control power delivery levels provided by the battery management circuitry 112, retrieve patent data stored in memory 128, and / or control other aspects of the functional parameters of the wearable device 104. In addition, the patient database 134 may also include implant control circuitry 138 to control various functional parameters of the implant device, via network 130 and wearable device 104. For example, the implant control circuitry 138 may control the implant component(s) 126 to define data collection intervals, intensity levels, etc. Of course, in some embodiments, the patient database 134 may incorporated with the power transmitter circuitry 102.

[0023] FIG.2 illustrates an example use-based embodiments of the continuous power delivery and data monitoring systems described herein. FIG.2 illustrates continuous power delivery and data collection at various stages of a patient’s health protocol, for example, in-hospital recovery (top left image), continuous power delivery and data collection during rehabilitation activities (Middle image), and post-surgical rehabilitation, e.g., continuous power delivery and data collection during at-home care activities (bottom right image). As a general matter, the continuous power delivery and data monitoring systems described herein have broad applications for patient monitoring, from post-surgical recovery monitoring to assessment of therapeutic interventions, and as a sensing and stimulation interface for long-term disease management.

[0024] FIGS. 3A-3D illustrate various features of a continuous power delivery and data monitoring system according to one embodiment of the present disclosure. FIG. 3A illustrates a continuous power delivery and data monitoring system 300 according to one embodiment of the present disclosure. In this embodiment, the far-field power transmitter circuitry 102’ is embodied as 915MHz power caster circuitry 302 that can be placed in areas where subjects spend most of their time, which can be discerned subjectively or through neural-network driven behavioral analysis. The wearable device 104’ of this embodiment includes Bluetooth Low Energy communication circuitry 304 and NFC transceiver control circuitry 118’, which may be embodied as an ultra-low-power microcontroller, for example, an STM32WB55, with the capacity for meshDocket No.: UA22-173PCT networking using, for example, Thread and Zigbee communication protocols. An antenna matching and tuning circuit on the NFC interface island allows for straightforward replacement of the NFC antenna for different applications, e.g., larger coverage area, different NFC ISO standards, different communication frequencies, etc.

[0025] FIG. 3B (top) is a photograph of the wearable device 104’ on a subject’s upper arm. As illustrated in the bottom image, the wearable device 104’ is separated into functional “islands” joined via serpentine interconnects. The serpentine structures between islands improve overall system robustness and conformality, as they minimize strain on the copper traces and deform more readily than linear traces. Battery management circuitry on the wearable enables high efficiency recharge and battery maintenance through a far field antenna and has advanced low power features that can isolate the electrochemical energy storage and charging circuitry from the digital circuitry, to reduce idle state power usage. Embedding the electronics into a 3D printed flexible thermoplastic polyurethane (TPU) mesh offers improved conformality, ensures fixation over the implant site during continuous operation, and avoids issues with skin turnover inherent to devices that use adhesive-based fixation. In this embodiment, all electronics are coated in flexible UV-cure TPU resin for improved environmental resistance and physical protection. In Fig.3A (bottom), an exploded model shows the layers that comprise the wearable electronics. The NFC antenna 120’ and far field power harvesting antenna 110’ are illustrated. Readily available off-the-shelf components, flexible Kapton based flexible circuits and mesh fabrication techniques that can be scaled through injection modeling and die cutting make the platform scalable.

[0026] FIG. 3C is a photograph of an NFC-capable implant device 106’ located within the NFC coil antenna 120’ of the wearable device 104’ demonstrating the concept of readout and powering. The wearable antenna is larger than many currently available fully implantable, wireless, battery- free devices, allowing for continued interfacing even through location mismatch and translational movement in highly mobile areas of the body. In FIG. 3D, increasing thicknesses of tissue phantom were placed between the NFC-capable implant device 106’ and the wearable device 104’, with data acquisition rate from the implant device 106’ decreasing as thickness increased due to lowered energy availability at the implant device 106’. The data show that the wearable can energize and read from devices implanted up to 30mm deep with over 50Hz sampling rate, sufficient for continuous monitoring of physiological signals such as pulse, blood oxygen, glucose levels, and body temperature.Docket No.: UA22-173PCT

[0027] FIGS.4A-4C illustrate various aspects of long-term human trials of the continuous power delivery and data monitoring system 400 according to embodiments described herein. FIG. 4A is a photograph of the wearable device 104’ on a subject’s upper arm. The device fits comfortably under various types of clothing (FIG. 4B) with no significant losses in power harvesting nor impairment to NFC communication. To demonstrate long-term, continuous data collection, a 7- day experiment is performed with two subjects. The wearables placed on the subjects’ right proximal bicep, as this part of the body undergoes regular movement and should induce consistent repetitive strain on the electronics and mesh, is programmed to power and read data from the mock implant that uses a epidermal NFC wearable that records temperature. Plots in FIG. 4C show data rate (top portion of plot 400) and battery life (bottom portion of plot 400) of the wearable device 104’ over a continuous one-week period. During the test, the wearable device 104’ is recharged by a far field power caster 102’ on the subjects’ work desks (not shown). Battery voltage at the wearable device 104’ is sampled at regular intervals, with shaded regions indicating charging by the wireless power caster 102’. Recorded battery voltage does not fall below 3.5 V during the experiment, demonstrating robust recharging and operation with no interaction required from the subject.

[0028] FIGS. 5A-5F illustrate a continuous power delivery and data monitoring system 500 according to one embodiment. In this embodiment, the implant device 106’ is an osseosurface device. FIG.5A is a photograph of implantable osseosurface device 106’ and exploded 3D model showing device composition. FIG.5B is a functional block diagram for implantable device. The 13.56MHz antenna shown in energy harvesting block is also capable of transmitting data. FIG. 5C is a graph of load sweeps for proprietary STMicroelectronics NFC tag power harvesting using ISO 15693. Full wave rectifier results show enhanced power harvesting over original osseosurface devices published previously. FIG.5D illustrates strain data collected from slowly rocking sheep to shift weight onto leg. Strain is relative. FIG.5E is a graph of internal tibia surface temperature recorded during a data collection session. FIG.5F is a graph of data rate in kilobits per second vs days since implantation, showing no degradation in data transmission over monthslong operation.

[0029] FIGS.6A-6E illustrate various aspects of a large animal model 600 of the continuous power delivery and data monitoring system according to one embodiment. FIG.6A is a photograph of wearable device fixed above target implant on sheep left posterior leg. FIG. 6B is an X-ray showing location of wearable relative to implant. FIG. 6C is a photo during explantation ofDocket No.: UA22-173PCT implantable device showing minimal tissue response and fibrous capsule. FIG.6D are time lapse photos of sheep a walking with data makers for hoof, ankle, tibia implant / wearable, and stifle. Video data was analyzed using a deep neural network to best match data from implant. FIG.6E is a graph and photos of time synchronized strain recording and corresponding video frames of the sheep gait cycle.

[0030] FIGS. 7A-7F illustrate long-term results 700 of the large animal study of the continuous power delivery and data monitoring system of FIGS.5 and 6. FIG.7A is a diagram showing gait data recorded over days since implantation. Accurate strain data was recorded four months post- implantation with no loss in data quality over study duration. FIG. 7B is a graph of strain data extracted from single femur implant over chronic time period. Data show loading of femur during rocking of sheep and demonstrate consistency of device operation over time. FIG.7C is a graph of temperature data from sheep tibia showing circadian rhythm. FIG. 7D is a graph of strain profiles of experimental vs contralateral bone showing minimal changes in bone integrity. FIG. 7E is a fluorescent microscopy image showing osteogenesis at 93 days post implantation. Calcein was administered 10 and 3 days before sacrifice. FIG. 7F is an SEM image (left) and CT scan (right) of implanted bone showing osseointegration and bone overgrowth.

[0031] Wireless, battery-free implantable electronics enable data collection over long time scales (months to years), as they are not limited by electrochemical power supplies. Through wireless power transfer methods, such as inductive coupling, enough power is provided for implants to operate continuously with complex sensing and stimulation modalities, although the power casting devices are often tethered or, when wearable, have large battery supplies. Therefore, in order to provide continuous monitoring, subjects are physically constrained to the tethered reader or must constantly manage the battery life of the wearable.

[0032] The teachings herein provide a wireless, wearable device capable of transferring power and exchanging data with wireless, battery-free implantable devices. Far-field power harvesting enables wireless charging of the wearable’s power bank with no modification to daily routines and no interaction required from the wearer. The wearable mesh has a small, personalized form factor and may be manufactured using a basic FDM 3D printer with minor off-the-shelf modifications. Using standardized RF communication protocols and commercially electronic components allows for an accessible, easily produced wearable power casting and data transfer device that is readily adapted to any NFC-capable implant, including already existing devices.Docket No.: UA22-173PCT

[0033] The present disclosure demonstrates the ability of this device to energize and communicate with a fully implanted, battery-free bone strain sensor and send collected data over BLE. Continuous data links with implants were maintained through several centimeters of highly mobile muscle tissue in live, freely moving sheep during several fifteen-minute data recording sessions. The gait profile of the sheep was accurately reconstructed using the strain data collected and correlated to video recordings, as shown in FIG. 6D. Collected data is stored locally on a BLE- capable laptop, although can also be stored on an Amazon Web Services (AWS) for immediately storing recorded data securely in the cloud.

[0034] In human trials, the device was worn on the arm and powered an epidermal NFC-capable sensor for a week of continuous wear, demonstrating the feasibility of chronic vitals monitoring without any input from a patient. This experiment also showcases the ability to wirelessly charge the wearable without tethering or removal of the device.

[0035] Additionally, the present disclosure illustrates enhanced capabilities of osseosurface electronics, specifically post-implantation non-surgical adjustment of sensor gain and biasing. Long-term animal studies involving osseosurface devices demonstrate continuous operation in vivo for over six months, sufficient lifetime for monitoring post-fracture bone healing and evaluating bone strength in humans. Additionally, four-point bending of implanted bones revealed minimal differences in strain profiles relative to non-implanted contralaterals (see Fig. 7D), showing that osseosurface devices do not compromise bone integrity. TGF-β / CPC-coatings of the strain gauges fostered osteogenesis and accelerated osseointegration, with several devices showing complete bone overgrowth after several months (see FIG. 7E & F).

[0036] Combined, these devices offer unprecedented continuous 24 / 7 monitoring of patient vital signs for weeks to months while allowing patients to move freely and without changes in routine or lifestyle. Integrating cloud-based recording allows for secure transfer and storage of bio signals and allows physicians to monitor patients remotely, shifting point-of-care from hospitals to homes. Remote monitoring lowers healthcare expenditures, reduces strains on hospitals and inpatient clinics, and is more convenient as telehealth becomes more common.

[0037] Implantable device fabrication

[0038] Wearable and implantable electronics were fabricated on a flexible panel structure and sent for external manufacturing. The flexible PCB stackup consists of a polyimide substrate (25µm) between two layers of ENIG-finished copper (18µm / layer). Additional polyimide layersDocket No.: UA22-173PCT (27.5µm / layer) were used on both sides as solder mask. Devices were depaneled using UV (355 nm) laser ablation (LPKF; Protolaser U4) and cleaned via sonication (Vevor; TS391LT) in isopropanol (IPA). Surface mount components were placed and reflowed manually with low temperature solder paste (Chip Quick; TS391LT).

[0039] The contacts of metal-foil strain gauges (Micro Measurements; ED-DY-125BZ-10C / E) were cleaned with soldering flux (Kester; 959T) and integrated into implantable devices using a soldering iron and low temperature solder paste. After assembly, devices were cleaned once more with IPA and components were then covered with heat cure adhesive (Henkel; Loctite 3621) to secure solder joints and reduce device surface irregularities. Devices were then cured in an oven at 100°C for ten minutes.

[0040] Wearable mesh fabrication

[0041] High-resolution 3D scans of subject arms and legs were collected using a handheld 3D scanner (Shining 3D, EinScan Pro HD) and unfolded into 2D maps using open-source 3D creation software (Blender Foundation, Blender). Flexible mesh drawings referenced these 2D maps to ensure accurate wearable fit and placement.2D mesh drawings were exported from AutoCAD and imported into a 3D modeling software (Dassault Systèmes, Solidworks) for extrusion. Stereolithography (STL) files were generated from the 3D model and imported into 3D slicing software (Prusa3D, PrusaSlicer) to generate machine code for a 3D printer. A fusion deposition modeling printer (Creality, CR-10s) was outfitted with a custom x-axis carriage that housed a direct drive extruder (Creality, Sprite Extruder Pro), hotend, and automatic bed leveling unit (Antclabs, BLTouch). A TPU filament (NinjaTek, NinjaFlex) was printed at 30 mm / s and 225°C with a bed temperature of 45°C. After printing, segmented sections of the mesh structure were joined by melting TPU material together at junctions to form the completed linear structures.

[0042] Wearable device electronics were fabricated in the same manner as implantable device electronics, cleaned with IPA post-assembly, and embedded into the 3D-printed TPU mesh. After embedding, the electronics were covered in a transparent, flexible, UV-curable TPU resin (3DMaterials; SuperFlex) to provide wear resistance and protect them from the external environment. The resin-covered electronics were cured with a UV lamp (24W) for fifteen minutes.

[0043] Characterization of the wireless strain sensor

[0044] Implant wireless power-harvesting capability: RF power at 2W was provided by a High Frequency (HF) Long Range RFID Reader (Feig Electronic GmbH, ID LR2500). The primaryDocket No.: UA22-173PCT antenna was connected to a tuning / matching circuit board and tuned at 13.56 MHz with a voltage standing wave ratio (VSWR) below 1.5. A 2-turn circular primary antenna with diameter of 20 cm was used to power devices implanted onto sheep femurs and tibias.

[0045] Experimental bone strength characterization

[0046] Mechanical characterization of experimental bone strength was performed using a servo- hydraulic MTS (MTS Systems Corporation, Series 810).

[0047] Animal Studies

[0048] All animal studies were performed following an IACUC approved protocol. Six adult sheep in total were used (3 male, 3 female) for long-term in vivo data collection. Implanted devices were sterilized using ethylene oxide and aerated for 24 hours prior to placement. Sheep were anesthetized using isoflurane prior to surgery. An 8cm incision was made over the left posterior leg. The lateral surface of the femur was exposed subperiosteally, and two devices were placed at the midpoint of the bone, spaced approximately 5cm apart with strain gauges oriented axially along the femur. TGF-β and CPC-coated gauges were fastened in place using vicryl sutures tied around the circumference of the femur before the incision was closed. Next, a 6cm incision was made anteriorly along the left posterior tibia. The medial and lateral surfaces of the tibia were exposed subperiosteally through this anterior approach. Two devices total were placed on the medial and lateral surfaces of the tibia with TGF-β / CPC-coated gauges oriented axially. Gauges were secured using vicryl sutures tied around the circumference of the tibia before the incision was closed. Data collection began approximately three weeks post implantation to allow for wound healing and osseointegration of the strain gauges.

[0049] Long-term implant data collection

[0050] A High Frequency (HF) Long Range RFID Reader (Feig Electronic GmbH, ID LR2500) was connected to 2-turn circular antenna with diameter 20cm and adjustable antenna tuning circuit. The coil antenna was embedded into a 3D printed PLA (OVERTURE, 1.75mm PLA) housing to provide rigidity and maintain structural integrity. The tuning circuit was adjusted to match to 50 Ohms at 13.56 MHz. Large animal subjects (sheep) were led onto a purpose-built treadmill and a camera (1920 x 1080, 60 frames per second, iPhone 14 Pro Max) was placed sagittally to capture movement of all four limbs. For gait recording experiments, the treadmill was activated, and subjects were able to walk for two minutes for each osseosurface device. For non-gait strain recording sessions, the treadmill was left off and animals were gently rocked by researchers atDocket No.: UA22-173PCT ~0.5Hz for two-minute intervals for each osseosurface device. During data collection, the field output power was set between 5.75W – 6.25W, and the coil antenna was pressed against the subject over the implant site. Raw hex data was collected from each implant via HF Reader control software (Feig Electronic GmbH, ID ISOStart+ V11) scripts. The data were extracted and formatted using MATLAB. Implant biasing and gain were adjusted as needed.

[0051] Implant biasing and gain adjustment

[0052] The strain sensing circuit was implemented using a Wheatstone bridge configuration, with two 1kΩ 0.1% resistors (Vishay / Dale, TNPW02011K00BEED) forming one half of the bridge, and a high precision 1kΩ metal-foil strain gauge (Micro Measurements; ED-DY-125BZ-10C / E) and 5kΩ digital potentiometer (Microchip Technology, MCP4561) in parallel with a 2.2kΩ 5% resistor forming the other half. To adjust biasing of the bridge, values stored in the NFC tag are read upon boot by the microcontroller and loaded into the digital potentiometer via I2C communication. For gain adjustment of the output stage, the low-power, high-precision instrumentation amplifier (Maxim Integrated, MAX41400) uses two digital input pins to adjust gain. These pins are connected to GPIOs on the microcontroller, which are set upon boot using values retrieved from the NFC tag.

[0053] Gain of individual implants was adjusted as necessary to maintain significant strain signal amplitude without voltage clipping. Wheatstone bridge biasing was adjusted to account for pre- strain of the strain gauge introduced during surgical implantation and subsequent wound healing process.

[0054] Deep Neural Net Analysis

[0055] Markerless pose estimation software, DeepLabCut (version 2.2.b6), was used to perform deep neural network analysis. The neural net was trained with several 5-minute long clips, where 20 frames from each were labeled and used as training material. The training session was performed with 50,000 iterations on Puma, a High-Performance Computer at the University of Arizona’s High Performance Computing Lab. After training, a 12-second video clip with consistent gait was tracked and analyzed to extract and plot the coordinates for hoof, ankle, wearable device, and stifle joint. The data were then used to sync data acquired from the wearable device.

[0056] As used in this application and in the claims, a list of items joined by the term “and / or” can mean any combination of the listed items. For example, the phrase “A, B and / or C” can meanDocket No.: UA22-173PCT A; B; C; A and B; A and C; B and C; or A, B and C. As used in this application and in the claims, a list of items joined by the term “at least one of” can mean any combination of the listed terms. For example, the phrases “at least one of A, B or C” can mean A; B; C; A and B; A and C; B and C; or A, B and C.

[0057] Any of the operations described herein may be implemented in a system that includes one or more non-transitory storage devices having stored therein, individually or in combination, instructions that when executed by circuitry perform the operations. “Circuitry”, as used in any embodiment herein, may comprise, for example, singly or in any combination, hardwired circuitry, programmable circuitry such as processors comprising one or more individual instruction processing cores, state machine circuitry, and / or firmware that stores instructions executed by programmable circuitry and / or future computing circuitry including, for example, massive parallelism, analog or quantum computing, hardware embodiments of accelerators such as neural net processors and non-silicon implementations of the above. The circuitry may, collectively or individually, be embodied as circuitry that forms part of a larger system, for example, an integrated circuit (IC), system on-chip (SoC), application-specific integrated circuit (ASIC), programmable logic devices (PLD), digital signal processors (DSP), field programmable gate array (FPGA), logic gates, registers, semiconductor device, chips, microchips, chip sets, etc.

[0058] The storage device includes any type of tangible medium, for example, any type of disk including hard disks, floppy disks, optical disks, compact disk read-only memories (CD-ROMs), compact disk rewritables (CD-RWs), and magneto-optical disks, semiconductor devices such as read-only memories (ROMs), random access memories (RAMs) such as dynamic and static RAMs, erasable programmable read-only memories (EPROMs), electrically erasable programmable read-only memories (EEPROMs), flash memories, Solid State Disks (SSDs), embedded multimedia cards (eMMCs), secure digital input / output (SDIO) cards, magnetic or optical cards, or any type of media suitable for storing electronic instructions. Other embodiments may be implemented as software executed by a programmable control device. Also, it is intended that operations described herein may be distributed across a plurality of physical devices, such as processing structures at more than one different physical location.

[0059] The terms and expressions which have been employed herein are used as terms of description and not of limitation, and there is no intention, in the use of such terms and expressions, of excluding any equivalents of the features shown and described (or portions thereof), and it isrecognized that various modifications are possible within the scope of the claims. Accordingly, the claims are intended to cover all such equivalents. Various features, aspects, and embodiments have been described herein. The features, aspects, and embodiments are susceptible to combination with one another as well as to variation and modification, as will be understood by those having skill in the art. The present disclosure should, therefore, be considered to encompass such combinations, variations, and modifications.

[0060] Reference throughout this specification to “one embodiment” or “an embodiment” means that a particular feature, structure, or characteristic described hi connection with the embodiment is included in at least one embodiment. Thus, appearances of the phrases “in one embodiment” or “in an embodiment” in various places throughout this specification are not necessarily all referring to the same embodiment, Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

Claims

Docket No.: UA22-173PCT recognized that various modifications are possible within the scope of the claims. Accordingly, the claims are intended to cover all such equivalents. Various features, aspects, and embodiments have been described herein. The features, aspects, and embodiments are susceptible to combination with one another as well as to variation and modification, as will be understood by those having skill in the art. The present disclosure should, therefore, be considered to encompass such combinations, variations, and modifications. [0060] Reference throughout this specification to “one embodiment” or “an embodiment” means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, appearances of the phrases “in one embodiment” or “in an embodiment” in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.Docket No.: UA22-173PCT What is claimed is:

1. A continuous power delivery system for implantable devices, comprising: a power transmitter configured to generate a first power signal and communicate the first power signal via a first communication and powering protocol; a wearable device configured to be worn on a patient’s body, the wearable device configured to communicate with the power transmitter and receive the first power signal via the first communication and powering protocol, the wearable device including battery management circuitry to a control a charging of a battery using the first power signal and to control a discharge of the battery to generate a second power signal; the wearable device further configured to communicate the second power signal via a second communications and powering protocol; and an implant device configured to be implanted in the patient’s body, the implant device configured to communicate with the wearable device and receive the second power signal via the second communications and powering protocol, the implant device include one or more implant components configured to be powered by the second power signal.

2. The continuous power delivery system of claim 1, wherein the implant device further configured to communicate data generated by the one or more implant components and transmit the data generated by the one or more implant components to the wearable device.

3. The continuous power delivery system of claim 1, wherein the first communication protocol is a far field communications protocol.

4. The continuous power delivery system of claim 1, wherein the second communications protocol is a near field communications protocol.

5. The continuous power delivery system of claim 1, wherein the wearable device is further configured to communicate with a patient database via a third communications protocol.Docket No.: UA22-173PCT 6. The continuous power delivery system of claim 1, wherein the wearable device and the power transmitter each further include a far field antenna to provide communication between the wearable device and the power transmitter.

7. The continuous power delivery system of claim 1, wherein the wearable device and the implant device each further include a near field antenna to provide communication between the wearable device and the implant device.

8. A continuous power delivery system for implantable devices, comprising: a wearable device configured to be worn on a patient’s body, the wearable device configured to communicate with a power transmitter and receive a first power signal via a first communication and powering protocol, the wearable device including battery management circuitry to a control a charging of a battery using the first power signal and to control a discharge of the battery to generate a second power signal; the wearable device further configured to communicate the second power signal via a second communications and powering protocol; and an implant device configured to be implanted in the patient’s body, the implant device configured to communicate with the wearable device and receive the second power signal via the second communications and powering protocol, the implant device include one or more implant components configured to be powered by the second power signal.

9. The continuous power delivery system of claim 8, wherein the implant device further configured to communicate data generated by the one or more implant components and transmit the data generated by the one or more implant components to the wearable device.

10. The continuous power delivery system of claim 8, wherein the first communication protocol is a far field communications protocol.

11. The continuous power delivery system of claim 8, wherein the second communications protocol is a near field communications protocol.

Images