Tissue temperature monitoring using electrical impedance during a cutting procedure

Abstract

Technologies are provided for estimation and monitoring of temperature of tissue of a living subject, while the tissue is being cut m an interventional procedure. Temperature may be estimated by measuring impedance of the tissue directly using a. cutting tool that cuts the tissue. Changes to the operation of the cutting tool can be caused in response to the temperature of the tissue satisfying or exceeding a threshold value.

Description

Attorney Docket No.: 043505.01879 APD10143PCT01 TISSUE TEMPERATURE MONITORING USING ELECTRICAL IMPEDANCE DURING A CUTTING PROCEDURE CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit of and priority to U.S. Provisional Patent Application No. 63 / 692,324, filed September 9, 2024, the contents of which application are hereby incorporated by reference herein in their entireties. SUMMARY

[0002] The following presents a simplified summary of one or more aspects to provide a basic understanding of such aspects. This summary is not an extensive overview of all contemplated aspects and is intended to neither identify key or critical elements of all aspects nor delineate the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form as a prelude to the more detailed description that is presented later.

[0003] In some aspects, the disclosure provides a system including: an impedance measurement device integrated into a cutting apparatus having a cutting tool that is configured to be in contact with tissue of a subject and further configured to cut the tissue; multiple electrodes coupled with the impedance measurement device to measure electrical impedance of the tissue as the tissue is being cut, with at least one of the multiple electrodes being integrated into the cutting tool; and a control device configured to: determine, based on the electrical impedance, an estimate of temperature of the tissue as the tissue is being cut; and cause a feedback device to present an indication of the estimate of the temperature of the tissue as the tissue is being cut, with the indication being based on a deviation of the estimate of temperature of the tissue from a baseline. In addition, or in other aspects, the control device is further configured to: determine that the deviation of the estimate of temperature from the baseline satisfies or exceeds a threshold value; and modify, based on the threshold value, an operation of the cutting tool or an operation of another device included in the cutting apparatus or functionally coupled to the cutting apparatus. BRIEF DESCRIPTION OF THE DRAWINGS

[0004] The accompanying drawings form part of the disclosure and are incorporated into the subject specification. The drawings illustrate example aspects of the disclosure and, inAttorney Docket No.: 043505.01879 APD10143PCT01 conjunction with the following detailed description, serve to explain at least in part various principles, features, or aspects of the disclosure. Some aspects of the disclosure are described more fully below with reference to the accompanying drawings. However, various aspects of the disclosure can be implemented in many different forms and should not be construed as limited to the implementations set forth herein. Like numbers refer to like elements throughout.

[0005] FIG.1 is a schematic diagram of an operational environment including an example of a system to monitor tissue temperature using electrical impedance, in accordance with one or more aspects of this disclosure.

[0006] FIG. 2 illustrates an example electrode arrangement for measurement of electrical impedance as tissue of a subject is being cut, in accordance with one or more aspects of this disclosure.

[0007] FIG. 3A presents perspective views of a cutting device (also referred as cutting tool) having multiple electrodes integrated into the cutting device, in accordance with one or more aspects of this disclosure.

[0008] FIG. 3B presents a perspective view of an electrode patch that can may be assembled with a cutting device (also referred to a cutting tool), in accordance with one or more aspects of this disclosure.

[0009] FIG. 3C presents a perspective view of an end section of a cutting device (also referred to a cutting tool) resulting from assembling the electrode patch shown in FIG.3B and the cutting device shown in FIG.3A, in accordance with one or more aspects of this disclosure.

[0010] FIG. 4 is a schematic block diagram of a computing device that may be part of a system to monitor tissue temperature using electrical impedance, in accordance with one or more aspects of this disclosure.

[0011] FIG.5A is a two-dimensional line plot that illustrates temporal changes of various quantities (magnitude of impedance, resistance, and resistivity) derived from electrical impedance of a phantom sample that emulates tissue of subject, in accordance with one or more aspects of this disclosure.

[0012] FIG. 5B presents a chart that includes respective line-scatter plots of temperature as a function of time, resistance as a function of time, and reactance as a function of time, where all datasets have been obtained after a cutting procedure has been paused, in accordance with one or more aspects of this disclosure.Attorney Docket No.: 043505.01879 APD10143PCT01

[0013] FIG.6 is a schematic diagram of baseline and an example threshold level structure for quantities (magnitude of impedance, resistance, and resistivity) derived from impedance of tissue, in accordance with one or more aspects of this disclosure.

[0014] FIG. 7 is a schematic block diagram of an operational environment including the example system show in FIG.1, in accordance with one or more aspects of this disclosure.

[0015] FIG.8 is a flowchart of an example method for monitoring tissue temperature using electrical impedance, in accordance with one or more aspects of this disclosure. DETAILED DESCRIPTION

[0016] Embodiments of this disclosure address the issue of estimating temperature of tissue while cutting tissue. In an orthopedic procedure that involves cutting bone, there is a rise in temperature of the tissue being cut due to heat that is generated during the procedure. In this disclosure, cutting bone or other tissue refers to any process that removes an amount of bone or tissue. Thus, cutting may include drilling, sawing, shaving, reaming, ablating, and / or similar processes. For example, material removal and friction between the bone and a surface of the cutting tool (e.g., cutting tip or drill bit) in use result in heat generation. The heat that is generated may cause an increase in temperature of the remaining tissue. Higher temperatures change the mechanical properties of tissue and may cause irreversible tissue damage, including tissue necrosis. For example, bone tissue at 47oC for about one (1) minute undergoes heat- induced osteonecrosis. Osteonecrosis refers to irreversible damage of bone that does not regenerate.

[0017] Commonplace techniques to mitigate tissue necrosis include using saline irrigation to remove at least some of heat or use a peck-and-drill method where bone cutting is performed intermittently. Using saline irrigation may not always be possible, as saline irrigation may cause obscuration of the tissue being cut, impact other sensor devices, dilute medication, or a combination thereof. Suction to remove the saline solution or other irrigation fluids also may cause interruptions during the procedure involving drilling, sawing, or cutting bone. In cases peck-and-drill is used, an accurate temperature of the bone tissue is unknown and may exceed, at least momentarily, a threshold temperature (e.g., 60oC) above which irreversible tissue damage, such as necrosis, occurs. Commonplace techniques to mitigate irreversible tissue damage (e.g., tissue necrosis) are merely palliative, and do not provide any direct information on tissue temperature. Consequently, commonplace techniques to mitigate irreversible tissueAttorney Docket No.: 043505.01879 APD10143PCT01 damage (e.g., tissue necrosis) cannot guide or otherwise inform much less automatically control, a cutting procedure so as to render the procedure safe.

[0018] Measuring temperature of tissue at the cutting edge (such as a drill tip, saw, or similar tool tip) while cutting the tissue is challenging due to various factors. For example, implementing a sensor device to measure temperature involves structural rigidity of the cutting edge. In addition, or as another example, implementing such a sensor device may be prohibitively expensive, or may lead to risks, such as breaking off during the procedure involving the drilling, cutting, or sawing of the tissue.

[0019] Further, a cutting edge made of a metal (e.g., a metal drill, metal saw, or blade) dissipates heat significantly faster than the tissue being cut. Thus, measuring temperature at the rear end or spaced apart from the cutting edge (cutting tip or drill bit, for example) may yield cooler temperature for the issue, therefore providing an inaccurate representation of temperature of tissue surrounding the site where the drilling, cutting, or sawing occurs. Such an inaccurate representation originates from propagation of heat through the thermally conductive cutting edge, which may lead to thermal losses yielding a higher tissue temperature at such a site.

[0020] Embodiments of this disclosure, individually or in combination, permit monitoring temperature of tissue of a living subject, while cutting tissue of the living subject, by measuring impedance of the tissue directly using a cutting tool that cuts the tissue. Measuring impedance of tissue during a cutting procedure permits estimating temperature of tissue in vivo, at or near the site where the cutting of the tissue occurs. By estimating temperature of the tissue as the tissue is being cut, a cutting procedure or operation of a cutting apparatus used in the cutting procedure, or both, may be configured based on the estimated temperature, to avoid harmful heating of the tissue as the cutting procedure is being implemented. Harmful heating can result in irreversible damage of the tissue, such as necrosis. As such, embodiments of this disclosure can avoid irreversible damage of the tissue being cut as the cutting procedure is performed. More specifically, in some cases, one attribute or combination of attributes of the cutting procedure may be adjusted based on the estimated temperature. Example of those attributes include “running” time (e.g., duration of the procedure), speed of a cutting edge, feed-rate, and irrigation of the cutting site or nearby locations. In addition, or in other cases, operation of a cutting tool used to be perform the cutting procedure may be directly controlled, particularly (yet not exclusively) in situations where tissue damage is expected.Attorney Docket No.: 043505.01879 APD10143PCT01

[0021] It is noted that principles and practical applications of this disclosure are not limited to a living subject. Indeed, in some cases, the subject may be a cadaver, as a cutting procedure can be monitored, and in some instances, controlled in accordance with aspects of this disclosure in order to avoid tissue damage in forensic scenarios, and in research and / or educational settings. Accordingly, embodiments in accordance with aspects of this disclosure can be applied to in vivo cutting procedures, in situ cutting procedures, ex vivo cutting procedures, and postmortem cutting procedures.

[0022] As is described in greater detail below, a computing device functionally coupled with a cutting apparatus can monitor the temperature of tissue as tissue is being cut. To that end, the computing device can obtain an impedance measurement signal from an impedance measurement device. The impedance measurement device can probe impedance of tissue in vivo, at the site where the tissue is being cut. The computing device can monitor the impedance measurement signal. Thus, in some instances, the computing device can detect a deviation from baseline relative to a threshold value. Simply for purposes of illustration, baseline refers to the local impedance of the tissue during procedure time in the absence of cutting. Baseline may change over time, as the cutting procedure is implemented. The threshold value may be one of multiple threshold values, each representing a respective risk level of causing irreversible tissue damage (e.g., tissue necrosis). Larger threshold values in the multiple threshold values may represent greater or increasing risk levels of causing irreversible tissue (e.g., tissue necrosis). Each threshold value of the multiple threshold values is configurable and may be personalized to a living subject based on one or more factors. Examples of those factors include age, biological sex, pre-existing conditions (e.g., osteoporosis), and the like. In some implementations, threshold values may be preconfigured and may be later adjusted relative to baseline impedance. That is, a threshold value may change relative to the baseline impedance, thus not being a fixed / absolute value from the baseline impedance. Further, or in other implementations, a threshold value may change at different depths or locations of the tissue from an outer surface of the tissue. Furthermore, or in yet other implementations, a threshold value may be determined intraoperatively at the beginning of a cutting procedure where irreversible tissue damage (e.g., tissue necrosis) threshold value is determined on a tissue that is to be cut. In one example, during the beginning of cutting, a small piece of bone may be intentionally heated by cutting the bone in order to determine a threshold value to calibrate the cutting procedure. Such a threshold value represents an example of a personalized threshold value.Attorney Docket No.: 043505.01879 APD10143PCT01

[0023] In response to detecting a deviation from baseline impedance relative to a threshold value, the computing device can cause a device to perform an action or multiple actions. In some scenarios, the device may be a display device, and the action(s) may include presenting indicia (visual, for example) indicative or representative of a current value of temperature of the tissue being cut and / or magnitude of electrical impedance of the tissue being cut. In addition, or in some cases, the action(s) may include presenting indicia (visual and / or aural) indicative of a further action that an operator of the cutting apparatus may / should perform based on the threshold value. In this disclosure, the operator may be surgeon, a veterinary, a healthcare practitioner, or another type of operator trained in the use of the cutting apparatus 110 for intervention on a subject. The indicia may be visual, e.g., text, an image, an animation, a chyron, etc.) and can be presented in a user interface available to the operator (e.g., a surgeon). The indicia may convey the further action and may be presented conspicuously in the user interface. The further action may be “continue procedure,” “exercise caution,” “inject coolant,” “consider pausing procedure,” or “stop procedure.” simply as a few examples. In addition, or in an alternative, the indicia may be aural, such as an utterance or an audible sound having a frequency based on the threshold value; for example, higher threshold values may have higher frequencies. The audible sound may be presented for a defined period of time. In cases where aural indicia are presented, the feedback device can be a speaker device. The display device and / or the speaker device may be assembled externally to the operator or may be a head- mounted visor (googled, glasses, or similar device, for example). In other scenarios, the device may be a wearable device that is wrist mounted or arm mounted, and the indicia may be haptic indicia (motion, compression, heat, etc.) providing a sensory effect of different strength based on the threshold value. In yet other scenarios, the feedback device may be an irrigation device, and the action caused by the control device may include supplying saline or other coolant to the site of the cutting. In still other scenarios, the device may be the cutting tool and, based on the threshold value, the computing device can cause the cutting apparatus to halt cutting.

[0024] The computing device may also cause two or more devices to perform respective actions in response to the deviation from baseline impedance relative to a threshold value. For example, the computing device may direct a display device to present visual indicia indicative of an action that should be performed, e.g., “inject coolant,” and also may direct an irrigation device to supply coolant. In some configurations, the irrigation device may be directed to supply the coolant after a defined time interval has elapsed after the display device presented the visual indicia.Attorney Docket No.: 043505.01879 APD10143PCT01

[0025] The monitoring of tissue temperature that is described in this disclosure drastically improves the technological field of orthopedic intervention / surgery in living subjects. For example, existing approaches to measure tissue temperature, such as thermocouple-based techniques and / or infrared-based techniques are not viable in clinical settings. In sharp contrast, embodiments of this disclosure, individually or in combination, can be readily implemented in in vivo clinical settings. As another example, tissue temperature may be monitored with minimal to no obstruction to a current surgical workflow. As another example, embodiments of this disclosure, individually or in combination, may speed up surgery by providing sensing and providing intraoperative, essentially real-time feedback on heating condition of the tissue being intervened / operated upon. As yet another example, embodiments of this disclosure, individually or in combination, may prevent osteonecrosis or other types of irreversible tissue damage, thus ensuring higher implant survival rate and mitigating (or event avoiding) other complications. As a further example, embodiments of this disclosure, individually or in combination, may permit automated control of the supply of irrigation fluids (supply on / off or amount of fluid supplied, for example), thus reducing obscuration and / or procedure workflow interruptions. As still another example, embodiments of this disclosure, individually or in combination, may enable autonomous surgical interventions.

[0026] In this disclosure, the term “subject” refers to a mammal, e.g., a human or another type of mammalian animal, or another type of complex biological organism. Non-human mammalian animals include dogs, cats, horses, chimpanzees and other non-human primates, livestock (such as cows, pigs, sheep, and the like), and wildlife (terrestrial and maritime). A subject also may be fish or another type of maritime animal, in some cases. A subject may further be another type of biological organism, such as a plant, a tree, or similar, in some cases.

[0027] With reference to the drawings, FIG. 1 is a block diagram of an example of an operational environment including an example of a system to monitor temperature of tissue of a living subject by using electrical impedance, in accordance with one or more aspects of this disclosure. The temperature of the tissue can be monitored while cutting the tissue of the subject, by measuring impedance of the tissue directly using a cutting tool that cuts the tissue. The example system 100 includes a cutting apparatus 110 having a cutting device 114 (which also may be referred to as cutting tool or cutting instrument). The cutting device 114 can include a drill, a saw, a slicer, or another type of tool used to cut bone. In a cutting procedure, the cutting device 114 is disposed in contact with bone tissue 164 within a section 160 of theAttorney Docket No.: 043505.01879 APD10143PCT01 body of a living subject 180. The cutting device 114 may include a cutting edge (e.g., a saw, a drilling bit, a heating element, etc.) to cut the bone tissue 164.

[0028] The cutting apparatus 110 also includes an impedance measurement device 120 that can probe impedance of the bone tissue 164 in vivo, at the site where the bone tissue 164 is being cut. To that end, during impedance measurement, the impedance measurement device 120 can inject a small, safe amount of current (or voltage) that does not cause an irreversible change to the tissue state. Such a small, safe amount of current can be specific to excitation frequency used to measure electrical impedance. For purposes of illustration, a small, safe amount of current may be in a range from about 1 A to about 10 mA, and a small, safe voltage may be in a range from 100 mV to 10 V. The impedance can be probed immediately prior to an amount of the bone tissue being removed by the cutting device 114. To that end, the cutting device 114 (or, in some cases, a portion thereof) can serve as a first electrode used to measure impedance of the bone tissue 164. In addition, another electrode 118 (referred to as return electrode 118) also can be used to measure impedance of the bone tissue 154, where the return electrode 118 serves a second electrode. Examples of the return electrode include an adhesive pad having a conductive element that may be placed on (e.g., mounted or adhered to) a limb of the subject (e.g., a thigh or shoulder of the subject), a lip clip, a wrist strap having a conductive element, or a bed electrode. In other cases, the return electrode 118 can be a repurposed electrode in an electrocautery system (not shown in FIG. 1). By using the first electrode and the return electrode 118 (as the second electrode), the impedance measurement device 120 can measure impedance in a two-point configuration. FIG. 2 illustrates an example electrode arrangement for measurement of electrical impedance, as tissue of a subject is being cut. The example electrode arrangement includes the cutting device 114 as the first electrode in such a two-point configuration and the return electrode 118 as the second electrode in the two-point configuration. Other elements of the cutting apparatus 110 are not depicted in FIG. 2 simply for the sake of clarity, to emphasize the two-point configuration for measurement of electrical impedance using the impedance measurement device 120. The impedance measurement device 120 can include one or more source devices to generate a current and / or a voltage, each of which may be a DC signal or an AC signal having a defined excitation frequency. The impedance measurement device 120 also can include multiple ports / pins to output and / or received an electrical signal in response to an applied current or voltage. The impedance measurement device 120 can further include circuitry to determine an electrical impedance and supply (e.g., generate and output) a signal indicative or otherwise representative of electricalAttorney Docket No.: 043505.01879 APD10143PCT01 impedance. The impedance measurement device 120 can include additional and / or alternative components to probe electrical impedance of tissue of a subject.

[0029] With further reference to FIG. 1, the return electrode 118 is optional, and thus, in some cutting procedures, the return electrode 118 may be absent or otherwise unused. In configurations in which the return electrode 118 is present and used during a cutting procedure, the return electrode 118 may be placed in contact with skin of the living subject 180, in a location separated from the site of the cutting procedure. As is illustrated in FIG.1, the site of the cutting procedure may be on a thigh of the living subject 180 and the return electrode 118 may be placed on a shoulder of the living subject 180.

[0030] In some configurations where the return electrode 118 is absent or unused during a cutting procedure, the impedance measurement device 120 can measure impedance between two locations of the cutting device 114 such that the current flows through the bone tissue 164 as the tissue is being cute. This disclosure is not limited in that respect, and the impedance measurement device 120 can measure impedance of the bone tissue 164 using two or more electrodes (up to 64 electrodes, for example). As an illustration, FIG.3A presents perspective views of an example of the cutting device 114 having multiple electrodes integrated into the cutting device 114, in accordance with one or more aspects of this disclosure. Specifically, the exemplified cutting device 114 has a shaft 310 and a drill bit 320, and four electrodes 314 integrated into the shaft 310. The disclosure is, of course, not limited to four electrodes 314 and more or fewer than four electrodes may be integrated into the shaft 310. In some configurations, the four electrodes 314 can shorted to produce, effectively, a single electrode. As another illustration, FIG. 3B presents a perspective view of an electrode patch 330 having multiple electrodes 334. Although the arrangement of the multiple electrodes 334 corresponds to concentric rings of electrodes, the disclosure is not limited in that respect. Other arrangements of the multiple electrodes 334 may be implemented. Further, more or fewer electrodes 334 that those shown in FIG.3B may be implemented. The electrode patch 330 can be assembled with a cutting device in order to form another example of the cutting device 114 as is shown in FIG. 3C. Specifically, FIG. 3C presents a perspective view of an end section of that other example of the cutting device 114 that results from assembling the electrode patch 330 and the example cutting device shown in FIG.3A.

[0031] Regardless of the number of electrodes being used to measure impedance of the bone tissue 164, the impedance measurement device 120 can measure electrical impedance between 0.1 Hz to 10 MHz, at any sampling rate within a range from 0.01 sps to 100 ksps. ItAttorney Docket No.: 043505.01879 APD10143PCT01 is noted that electrical impedance is a complex value containing a real part and an imaginary part when the bone tissue 164 is excited with an alternating current or voltage of a defined frequency. The real part and the imaginary part of the electrical impedance correspond to resistance (R) and reactance (X). Hence, the electrical impedance is a complex number . It is also noted that the impedance measurement device 120 can probe other quantities such as admittance, conductance, and permittance. Without intending to be bound by modeling, it is noted that a biological electrical model may be an admittance model instead of an impedance model. Impedance is a complex inverse of admittance.

[0032] The impedance measurement device 120 can thus generate, during the cutting procedure, an impedance measurement signal that is time dependent. The impedance measurement device 120 can send or otherwise make available the impedance measurement signal to a control device 130 that is functionally coupled (e.g., communicatively coupled and / or electrically coupled) with the cutting apparatus 110.

[0033] The control device 130 is a computing device that has computing resources. The computing resources include, for example, one or more processors, one or more memory devices, one or more buses, one or more interfaces (e.g., input / output (I / O) interfaces, one or more network adapters, a combination thereof, or similar resources. The computing resources, individually or in a particular combination, can execute processor-accessible instructions to implement various functionalities of the control device 130 as is described herein. The processor-accessible instructions can be stored in at least one of the memory device(s). Data and control signaling also can be stored in the at least one memory device(s). Simply as an illustration, FIG. 4 is a block diagram of an example of a computing device 400 that may embody or may constitute the control device 130 (FIG.1). The computing device 400 includes one or more processor(s) 410, one or more memory devices 420 (collectively referred to as memory 420), one or more I / O interface(s) 430, and one more network interface(s) 440. The memory 420 can retain processor-accessible instructions 424, and data and control signaling (e.g., control bits) 428. The data may include calibration parameters and values of state variables defining one or more conditions of the cutting apparatus 110. The processor- accessible instructions 424 include processor-readable instruction and / or processor executable instructions. The processor-accessible instructions 424 and, in some cases, in combination with the data and control signal 428, configure the computing device 400 to perform the various functionalities of the control device 130 described in this disclosure. Execution of theAttorney Docket No.: 043505.01879 APD10143PCT01 processor-accessible instructions 424 by the one or more processors 410, individually or in combination, can cause the computing device to perform at least such various functionalities.

[0034] With further reference to FIG. 1, the control device 130 can monitor the temperature of tissue as tissue is being cut. To that end, the control device 130 can receive an impedance measurement signal from the impedance measurement device 120, and can monitor the impedance measurement signal or, in some cases, a temperature signal derived from the impedance measurement signal. The control device 130 can determine temperature from an impedance measurement using calibration parameters and a calibration function. The calibration parameters may be factory calibrated, personalized to a subject, or generated using a subject specific calibration, or a combination of the foregoing. The calibration function defines temperature in terms of electrical impedance and the calibration parameters. The calibration function can be a linear function, a non-linear function, or can be parameterized including data from multiple sources. The calibration parameters and the calibration function can be retained within a memory device integrated into the control device 130.

[0035] During a cutting procedure, as the cutting tool is in operation (e.g., a drill is spinning) changes in impedance may occur due to changes besides temperature changes in the tissue being cut. For example, impedance may change due to poor contact, at times, between the cutting device 114 and the tissue being cut (e.g., the bone tissue 164) and / or other factors. Those other factors may include, for example, saline solution from irrigation, blood, blood supply, medications, and the like. Hence, the control device 130 may use a state-dependent calibration to determine temperature of tissue as the tissue is being cut.

[0036] The state-dependent calibration may be based on an operation state of the cutting apparatus 110. The operation state of the cutting apparatus 110 may be dictated, at least partially, by motion or lack thereof of the cutting device 114. For example, an operation state corresponds to the tool spinning and another operation state corresponds to the tool being stationary. The control device 130 can identify operation status based on a state of the actuator switch 170 and / or data from another device. The other device can be integrated into the cutting apparatus 110 or may be external to the cutting apparatus 110. An accelerometer device is an example of that other device.

[0037] In addition, or in other cases, the operation state of the cutting device 114 may also be dictated by a state of an irrigation device (e.g., irrigating or not irrigating) that can operate in conjunction with the cutting device 114. Thus, an operation state of the cutting apparatus corresponds to the tool spinning and the irrigation device providing a coolant.Attorney Docket No.: 043505.01879 APD10143PCT01

[0038] As an illustration, in case the control device 130 determines that the cutting device 114 is stationary, a first calibration corresponding to stationary state may be appropriate for an accurate determination of tissue temperature. Thus, the control device 130 can estimate the temperature of tissue using the first calibration. In contrast, in case the control device 130 determines that the cutting device 114 is spinning or otherwise in motion, a second calibration corresponding to spinning state of the cutting device 114 may be sufficient for an accurate determination of tissue temperature. Thus, the control device 130 can estimate temperature of tissue using the second calibration.

[0039] In some implementations, the second calibration (corresponding to cutting device 114 in motion) may be defined in terms of a correction to the first calibration (corresponding to the cutting device 114 in stationary state). In one example, the correction may include an offset T (positive or negative) to the estimate of the temperature of the tissue that is obtained using the first calibration. In addition, or in other implementations, the correction may include a linear correction function or a non-linear correction function based on internal parameters of the cutting device 114, such as speed, torque, power consumption, current draw, voltage, or a combination those internal parameters. Further, or as an alternative, the linear correction function or the non-linear correction function may be based on data from external devices such as an accelerometer or switch to detect the state of the drill.

[0040] In some instances, the control device 130 can detect a deviation from baseline relative to a threshold value. Simply for purposes of illustration, baseline refers to an essentially steady value of tissue impedance (or, in some cases, tissue temperature) in the absence of cutting. The essentially steady value that corresponds to baseline may change over time, as the cutting procedure is implemented. The example system 100 can in some cases include a baseline sensor device (not depicted in FIG. 1) to correct for environment factors in the determination of baseline. The baseline sensor device can be one of a thermocouple, a thermometer chipset, or similar, for example, and can be placed in proximity of the tissue being cut.

[0041] As an illustration, FIG. 5A presents four different baselines during a time interval in which a cutting procedure is implemented. The four different baselines include a first baseline 510a, a second baseline 510b, a third baseline 510c, and a fourth baseline 510d. A deviation 514 (denoted by t) from baseline, at time t is shown for the sake of illustration. FIG. 5A also illustrates two types of temporal changes of various quantities—magnitude ofimpedance (|Z|), resistance (R), and real resistivity ( ')—derived from impedance of tissue.Attorney Docket No.: 043505.01879 APD10143PCT01 The magnitude of impedance, resistance, and real resistivity are inversely correlated with change in temperature. That is, an increase in temperature yields a decrease in each of the magnitude of impedance, resistance, and real resistivity. Hence, a first type of temporal change (represented by the letter “A” in FIG. 5A) corresponds to a decrease in magnitude of impedance as time progresses, caused by an increase in temperature due to bone cutting. Specifically, when temperature increases due to bone cutting, the conductivity of bone changes (e.g., decreases) leading to a decrease in measured magnitude of impedance. Such a decrease in magnitude of impedance as time progresses can be linear in time or non-linear in time.

[0042] Further, a second type of temporal change (represented by the letter “B” in FIG. 5A) corresponds to an increase in the magnitude of impedance caused by a decrease in temperature arising from bone cooling. Bone cooling may be accomplished by injecting an irrigation fluid into the cutting site or location(s) surrounding the cutting site, blood carrying heat away from the cutting site, and / or by thermal conductivity of the tissue itself in accordance with Newton’s law of cooling. More specifically, when temperature decreases due to bone cooling, the conductivity of bone returns to a baseline (usually increases towards the baseline) leading to an increase in measured magnitude of impedance. Simply as an illustration, FIG. 5B presents a line-scatter plot 530 of temperature as a function of time and a line-scatter plot 560 of resistance at 1 kHz as a function of time. Both datasets have been obtained after the cutting of a phantom sample emulating bone tissue has been paused (t = 0 s). Temperature is measured independently from measurements of electrical impedance yielding the resistance shown in the line-scatter plot 560.

[0043] As is described herein, electrical impedance is a complex number . In addition, because bone tissue is a biological material that may be part conductive and part dielectric, a state of the bone tissue may be represented by a complex resistivity . Here, the real resistivity and the imaginary resistivity are directly correlated with a change in temperature. That is, an increase in temperature yields an increase in each of the real resistivity and imaginary resistivity. Such an increase in real and imaginary resistivity as temperature increases can be linear or non-linear. Conversely, a decrease in temperature yields a decrease in each of the real and imaginary resistivity. Such a decrease in real and imaginary resistivity as temperature decreases can be linear or non-linear. Simply as a further illustration, FIG. 5B also presents a line-scatter plot 590 of reactance at 1 kHz as a function of time. The dataset is obtained after the cutting of a phantom sample emulating bone tissue has been paused (t = 0 s).Attorney Docket No.: 043505.01879 APD10143PCT01 The reactance is obtained from the same measurements of electrical impedance that yielded the resistance shown in the line-scatter plot 460.

[0044] With further reference to FIG.1, the control device 130 can use multiple threshold values, each representing a respective risk level of for irreversible tissue damage, such as tissue necrosis. Larger threshold values in the multiple threshold values may represent greater or increasing risk levels of causing irreversible tissue damage (e.g., tissue necrosis). Each threshold value of the multiple threshold values is configurable and may be personalized to a living subject based on one or more factors. Examples of those factors include age, biological sex, pre-existing conditions (e.g., osteoporosis), and the like. Simply as an illustration, FIG.6 is a schematic diagram of an example of a threshold value structure, in accordance with aspects of this disclosure. The example threshold value structure 600 include three threshold values relative to a baseline 604: first threshold value 610 (denoted by “Threshold A”), a second threshold value (denoted by “Threshold B”), and a third threshold value 630 (denoted by “Threshold C”). Each of the threshold values defines a threshold deviation from the baseline604: a first threshold deviation 614 (denoted by “ A”) for the first threshold value 610, a secondthreshold deviation 624 (denoted by “ B”) for the second threshold value 620, and a thirdthreshold deviation 634 (denoted by “ C”) for the third threshold value 630. Threshold A mayindicate a moderate risk level for irreversible tissue damage (e.g., tissue necrosis). Threshold B may indicate an elevated risk level for irreversible tissue damage (e.g., tissue necrosis). Threshold C may indicate an imminent danger of irreversible tissue damage (e.g., tissue necrosis). As is shown in the ordinate of the schematic diagram, each threshold value in the example threshold value structure 600 can apply to one of |Z|, R, or '.

[0045] Back to referring to FIG. 1, in response to the detecting a deviation from baseline relative to a threshold value, the control device 130 can cause another device to perform an action or multiple actions. That other device may be a feedback device 140 that also may be part of the example system 100. In some cases, the feedback device 140 is or includes a display device that may be assembled externally to the operator 150 or may be a head-mounted visor mounted on the operator 150. In those cases, the action includes presenting first indicia indicative or representative of a current value of estimated temperature of the tissue being cut and / or a magnitude of electrical impedance of the tissue being cut. In addition, or in some cases, the action also includes presenting second indicia indicative of a further action that, based on the threshold value, may be appropriate for an operator 150 or an autonomous robotic operator 154 of the cutting apparatus 110 to perform. As such, the first indicia and the second indiciaAttorney Docket No.: 043505.01879 APD10143PCT01 may be visual indicia and at least one of such indicia may be specific to the threshold value. The first indicia and the second indicia can be presented in a user interface that is shown in the display device. The user interface is available to the operator 150 or the autonomous robotic operator 154 (referred to as robot 154). Because temperature can change as tissue is being cut, the display device can redraw the first indicia and / or the second indicia as the tissue is being cut, to update such indicia as the tissue is being cut. Examples of visual indicia include text, an image, or an animation, such as a carousel or strip having moving text, a combination thereof, or similar.

[0046] Simply as an illustration, in cases the feedback device 140 is or includes a display device, the control device 130 can cause the display device to present user interface 142 (UI 142). The UI 142 includes first indicia 144a indicative or representative of a current value of estimated temperature of the tissue being cut and / or a magnitude of electrical impedance (or any other one of resistance, reactance, or real resistivity) of the tissue being cut. As is shown in FIG. 1, the first indicia 144a depicts a meter that has a dial 145 and a needle that points to the value of temperature and / or the value of the corresponding magnitude of electrical impedance (or any other one of resistance, reactance, or real resistivity) of the tissue being cut.The scale can present temperature in units of oC,oF, K, or as a percentage of a maximumtemperature before irreversible tissue damage (e.g., tissue necrosis) may occur. The first indicia 144a corresponds to a time taduring a cutting procedure.

[0047] In addition, or in some cases, the control device 130 can cause the display device to present second indicia within the UI 142. The second indicia may include a first visual element 146 indicative of an action that, at time ta, based on a magnitude of deviation from baseline, may be appropriate for the operator 150 or the robot 154 to perform. Because at tathe estimated temperature is in a range where irreversible tissue damage (e.g., tissue necrosis) is unlikely, the visual element 146 conveys that the cutting procedure can continue. The second indicia include other visual elements 147 that may convey other actions (e.g., “caution,” “exercise caution,” “coolant,” “inject coolant,” “pause,” “consider pausing procedure,” “stop,” or “stop procedure”). The first visual element 146 may be presented more conspicuously in the user interface 142 than the visual elements 147, to draw particular attention to the action conveyed by the visual element 146.

[0048] As the cutting procedure continues, at a time tb, the control device 130 can cause the display device to redraw the first indicia 144a, thus presenting other first indicia 144b within the UI 142, to update the estimated temperature of the tissue being cut. As is depictedAttorney Docket No.: 043505.01879 APD10143PCT01 in FIG.1, the estimated temperature at time tb is in an unsafe range that may cause irreversible tissue damage (e.g., tissue necrosis). Hence, the control device 130 can cause the display device to redraw the second indicia, presenting other second indicia including a first visual element 148 indicative of an action that, at time tb, based on a magnitude of deviation from baseline, may be appropriate for the operator 150 or the robot 154 to perform. Because at tbthe estimated temperature is in a range where irreversible tissue damage (e.g., tissue necrosis) is likely, the visual element 148 conveys that the cutting procedure should stop. The other second indicia also include other visual elements 149 that may convey other actions (e.g., “caution,” “exercise caution,” “coolant,” “inject coolant,” “pause,” “consider pausing procedure,” “go,” or “continue procedure”). The visual element 148 may be presented more conspicuously in the user interface 142 than the visual elements 149, to draw particular attention to the action conveyed by the visual element 149.

[0049] As the cutting procedure continues, the control device 130 can cause the display device to further update the first indicia and the second indicia presented in the UI 142 to convey a current estimated temperature of the tissue being cut and an action that may be appropriate at that estimate temperature. In other words, the control device 130 can cause the display device to redraw the UI 142 in nearly real-time, as a current estimate of temperature of tissue becomes available.

[0050] It is noted that presentation of the first and second indicia described above in connection with the UI 142 is simply illustrative. The disclosure is not limited in that respect, and in some cases, the display device presents either the first indicia or the second indicia within the UI 142.

[0051] In addition, or as an alternative, the feedback device 140 may include a speaker device, and the indicia presented by the feedback device 140 may include aural indicia. An example of aural indicia includes an audible sound having a frequency that is based on the threshold value. For instance, higher threshold values may cause presentation of an audible sounds having higher frequencies. Another example of aural indicia includes an audio segment corresponding to speech, such as an utterance (pre-recorded or synthetic), conveying an action associated with the threshold value.

[0052] In other cases, the feedback device 140 may be a wearable device that is wrist mounted or arm mounted. In some of those cases, the indicia that is presented by the feedback device 140 may be haptic indicia (vibration or other motion, compression, heat, etc.) providingAttorney Docket No.: 043505.01879 APD10143PCT01 a sensory effect of different strength based on a threshold value that has been satisfied or exceeded relative to baseline.

[0053] Also in response to detecting a deviation from baseline relative to a threshold value, the control device 130 may cause one or more devices (not shown in FIG. 1) to perform an action or multiple actions. Such device(s) may be an irrigation device, and an action may include supplying saline or other coolant to the site of the cutting. In addition, or as an alternative, the device(s) may be an actuator switch 170 (or a trigger) and, based on the threshold value, an action may include causing the cutting apparatus 110 to halt cutting. For instance, the actuator switch 170 (or trigger) can cause the cutting device 114 to transition to an idle state where movement ceases. That is, the control device 130 can cause the cutting device 114 to stop cutting. Further, or as another alternative, the device(s) may include a motor or another component of the cutting apparatus 110, and the one or more actions may include adjusting speed or feed rate of the cutting device 114.

[0054] The control device 130 also can cause two or more devices to perform respective actions in response to a deviation from baseline relative to a threshold value. For example, the control device 130 may direct a display device to present visual indicia indicative of an action that should be taken, e.g., “inject coolant,” and also may direct an irrigation device to supply coolant. In some configurations, the irrigation device may be directed to supply the coolant after a defined time interval has elapsed after the presenting the visual indicia.

[0055] FIG. 7 is a schematic block diagram of an operational environment including the example system 100 to monitor tissue temperature using electrical impedance, in accordance with one or more aspects of this disclosure. The one or more devices 710 can configure, individually or collectively, one or more procedure attributes of a cutting procedure. The device(s) 710 can include irrigation device(s), motors, actuators, one or more accelerometers, switches, microcontrollers, one or more power supplies, and similar devices. The control device 130 may direct at least one of the device(s) 710 to operate so as to cause the cutting apparatus 110 to operate according to defined procedure attributes. To do so, in some cases, the control device 130 can send an instruction and / or payload data to configure one or more operation parameter of a device that causes the device to operate according to at least one of the procedure attributes. The control device 130 and the feedback device 140 can be functionally coupled with one another via a communication architecture 720 that may include wireless links, wireline links, buses, routers, network adapters, a combination thereof, or similar communication elements.Attorney Docket No.: 043505.01879 APD10143PCT01

[0056] It is noted that the control device 130 and the feedback device 140 in FIG. 7 (and also in FIG. 1) are shown as separate from the cutting apparatus 110 simply for the sake of clarity and explanation. The control device 130 and the feedback device 140 may be mounted to, or otherwise present in, the cutting apparatus 110. Indeed, in some implementations, the control device 130 or the feedback device, or both, are integrated into cutting apparatus 110.

[0057] The cutting apparatus 110 also can include a power supply or an interface to couple the cutting apparatus 110 to a power supply or a power grid, to energize various components and / or devices of the cutting apparatus 110.

[0058] FIG.8 is a flowchart of an example of a method for monitoring tissue temperature using electrical impedance, in accordance with one or more aspects of this disclosure. A computing device or a system of computing devices can implement the example method 800 in its entirety or in part. To that end, each one of the computing devices includes computing resources that may implement at least one of the blocks included in the example method 800 and other methods described herein. The computing resources include, for example, CPUs; GPUs; TPUs; other types of processors or processing circuitry; memory; disk space; incoming bandwidth and / or outgoing bandwidth; interface(s) (such as I / O interfaces or APIs, or both); controller devices(s); power supplies; a combination of the foregoing; and / or similar resources. The computing device can include multiple modules (e.g., processor-accessible instructions) and can implement the example method 800 by executing one or more instances of such modules.

[0059] In some cases, a computing device implements the example method 800. The computing device may be or may include the control device 130 (FIG.1), for example.

[0060] At block 810, the computing device can obtain an impedance measurement signal corresponding to tissue (e.g., bone tissue) of a subject. The impedance measurement signal is time-dependent and may be obtained during a cutting procedure, as the tissue is being cut using a cutting apparatus (e.g., cutting apparatus 110) including a cutting device (e.g., cutting device 114). As is described herein, in some cases, the subject is a living subject, and the cutting procedure is implemented in vivo. In other cases, the subject may be a cadaver.

[0061] At block 820, the computing device can retain at least a portion of the impedance measurement signal. By retaining at least a portion of the impedance measurement signal, the computing device can determine temporal changes in impedance of the tissue of the living subject. Indeed, at block 830, the computing device can then monitor temperature of the tissue, as the tissue is being cut, by monitoring temporal changes in the impedance of the tissue of theAttorney Docket No.: 043505.01879 APD10143PCT01 living subject. As is described herein, in some implementations, the computing device can determine, using the impedance measurement signal, magnitude of impedance of the tissue, resistance of the tissue, reactance of the tissue, and / or real resistivity of the tissue. The computing device can then monitor temperature of the tissue, as the tissue is being cut, by monitoring temporal changes in the magnitude of the impedance, the resistance, the reactance, or the real resistivity of the tissue.

[0062] In some instances, during the cutting procedure, the impedance of the tissue deviates from baseline. At block 840a, the computing device can detect a deviation of the impedance measurement signal from baseline. To that end, the computing device can determine a temporal dependence of a number of values (samples) of electrical impedance from a current value to a defined number of prior values. A deviation of the impedance measurement signal from baseline can be identified when such a temporal dependence deviates from a substantially steady value. In response, the computing device can cause a device to perform one or more actions based on a magnitude of the deviation from baseline. In some cases, the magnitude of the deviation exceeds a threshold value, and, in response, the computing device can cause the device to perform particular action(s) based on the threshold value. The device can be part of the cutting apparatus or can be functionality coupled with the cutting apparatus. For example, the device can be the cutting device 114 or one of the devices 710 (FIG.7). In addition, or as another example, the device can be the feedback device 140. The one or more actions can include any of the actions described herein. In one example scenario, the device can include the cutting device 114 and the action(s) can include stopping the cutting device 114. In addition, or in another example scenario, the device can be the feedback device 140 can the action(s) can include presenting indicia in accordance with one or more aspects described herein. Further, or in yet another example scenario, the device can be a component of the cutting apparatus (e.g., the device can be one or a combination of device(s) 710) and the action(s) can include modifying the operation of the device in accordance with one or more aspects described herein. Modifying the operation of the device can include modifying, based on the threshold value, tissue cutting parameters of the cutting procedure implemented with the cutting apparatus, including the cutting tool. The cutting parameters including one or more of speed of the cutting tool, feed rate, or irrigation amount.

[0063] At block 840a, the computing device can detect restoration of the impedance measurement signal to baseline. To that end, the computing device can determine that a temporal dependence of a number of values (samples) of electrical impedance from a currentAttorney Docket No.: 043505.01879 APD10143PCT01 value to a defined number of prior values represents a substantially steady value (which is identified as the baseline value. As is described herein, as is illustrated in FIG. 5A, baseline during a time interval in the cutting procedure may be different from baseline in another time interval in the cutting procedure. Thus, the baseline that has been restored may not be the same baseline that may have caused the computing device to direct another device to perform one or more actions.

[0064] At block 850b, the computing device can cause the device to provide a notification to continue the cutting procedure. The device can be a feedback device (e.g., feedback device 140), and the computing device can cause the feedback device 140 to present various indicia (visual, aural, haptic, or a combination thereof) that, individually, or in combination, convey that the cutting procedure can continue.

[0065] Various additional or alternative example embodiments emerge from this Detailed Description and annexed drawings in connection with aspects of this disclosure, as disclosed by the following Clauses.

[0066] Clause 1. A system, comprising: an impedance measurement device integrated into a cutting apparatus having a cutting tool that is configured to be in contact with tissue of a subject and further configured to cut the tissue; multiple electrodes coupled with the impedance measurement device to measure electrical impedance of the tissue as the tissue is being cut, with at least one of the multiple electrodes being integrated into the cutting tool; and a control device configured to, determine, based on the electrical impedance, an estimate of temperature of the tissue as the tissue is being cut; and cause a feedback device to present an indication of the estimate of the temperature of the tissue as the tissue is being cut, with the indication being based on a deviation of the estimate of temperature of the tissue from a baseline.

[0067] Clause 2. The system of clause 1, wherein the control device is further configured to, determine that the deviation of the estimate of temperature from the baseline satisfies or exceeds a threshold value; and modify, based on the threshold value, an operation of the cutting tool and / or an operation of another device of the cutting apparatus.

[0068] Clause 3. The system of any of clause 1 or 2, wherein the feedback device comprises a display device, and wherein to cause the feedback device to present the indication, the control device is configured to cause the display device to present indicia representative of the estimate of the temperature.

[0069] Clause 4. The system of any of the preceding clauses, wherein the feedback device comprises a speaker device, and wherein to cause the feedback device to present the indication,Attorney Docket No.: 043505.01879 APD10143PCT01 the control device is configured to cause the speaker device to output at least one of an audible tone or an utterance.

[0070] Clause 5. The system of any of the preceding clauses, wherein the feedback device comprises a wearable device, and wherein to cause the feedback device to present the indication, the control device is configured to cause the wearable device to present haptic indicia.

[0071] Clause 6. The system of any of the preceding clauses, wherein modifying the operation of the cutting tool comprises stopping the cutting tool.

[0072] Clause 7. The system of any of the preceding clauses, wherein the multiple electrodes include a return electrode configured to couple the subject with the impedance measurement device.

[0073] Clause 8. The system of any of the preceding clauses, wherein the return electrode is one of an adhesive pad configured to be mounted to a section of skin of the subject at a location that is distant to a site of the cutting tool, a lip clip, a wrist strap, a bed electrode, or an electrode in an electrocautery system.

[0074] Clause 9. The system of any of the preceding clauses, wherein to determine the estimate of temperature of the tissue, the control device is further configured to evaluate a calibration function based on calibration data and the electrical impedance, with the calibration function being a linear function, a non-linear function, or a parameterized function including data from multiple sources.

[0075] Clause 10. The system of any of the preceding clauses, wherein the calibration data comprises one or more of factory calibrated data, data personalized to the subject, or data generated with a subject-specific calibration.

[0076] Clause 11. A computing device comprising: one or more processors; one or more memory devices having processor-executable instructions stored thereon that, in response to execution by the one or more processors, individually or in combination, cause the computing device at least to, obtain, as tissue of a subject is being cut using a cutting apparatus having a cutting tool, an impedance measurement signal indicative of electrical impedance of the tissue of the subject; determine, based on the electrical impedance, an estimate of temperature of the tissue as the tissue is being cut; and cause a feedback device to present an indication of the estimate of the temperature of the tissue as the tissue is being cut, with the indication being based on a deviation of the estimate of temperature of the tissue from a baseline.Attorney Docket No.: 043505.01879 APD10143PCT01

[0077] Clause 12. The computing device of clause 11, the one or more memory devices having further processor-executable instructions stored thereon that, in response to execution by the one or more processors, individually or in combination, further cause the computing device to, determine that the deviation of the temperature from the baseline satisfies or exceeds a threshold value; and modify, based on the threshold value, an operation of the cutting tool and / or an operation of another device of the cutting apparatus. Modifying the operation of the cutting tool or the other device can include modifying, based on the threshold value, tissue cutting parameters of the cutting procedure implemented with the cutting apparatus, including the cutting tool. The cutting parameters including one or more of speed of the cutting tool, feed rate, or irrigation amount.

[0078] Clause 13. The computing device of any of clause 11 or 12, wherein the feedback device comprises a display device, and wherein causing the feedback device to present the indication comprises causing the display device to present indicia representative of the estimate of the temperature.

[0079] Clause 14. The computing device of any of the preceding clauses, wherein modifying the operation of the cutting tool comprises stopping the cutting tool.

[0080] Clause 15. The computing device of any of the preceding clauses, wherein determining the estimate of temperature of the tissue comprises evaluating a calibration function based on calibration data and the electrical impedance, with the calibration function being a linear function, a non-linear function, or a parameterized function including data from multiple sources.

[0081] Clause 16. A method comprising: obtaining, as tissue of a subject is being cut using a cutting apparatus having a cutting tool, an impedance measurement signal indicative of electrical impedance of the tissue of the subject; determining, based on the electrical impedance, an estimate of temperature of the tissue as the tissue is being cut; and causing a feedback device to present an indication of the estimate of the temperature of the tissue as the tissue is being cut, with the indication being based on a deviation of the estimate of temperature of the tissue from a baseline.

[0082] Clause 17. The method of clause 16, further comprising: determining that the deviation of the estimate of temperature from the baseline satisfies or exceeds a threshold value; and modifying, based on the threshold value, an operation of the cutting tool and / or an operation of another device of the cutting apparatus. Modifying the operation of the cutting tool or the other device can include modifying, based on the threshold value, tissue cuttingAttorney Docket No.: 043505.01879 APD10143PCT01 parameters of the cutting procedure implemented with the cutting apparatus, including the cutting tool. The cutting parameters including one or more of speed of the cutting tool, feed rate, or irrigation amount.

[0083] Clause 18. The method of any of clause 16 or 17, wherein the feedback device comprises a display device, and wherein causing the feedback device to present the indication comprises causing the display device to present indicia representative of the estimate of the temperature.

[0084] Clause 19. The method of any of the preceding clauses, wherein modifying the operation of the cutting tool comprises stopping the cutting tool.

[0085] Clause 20. The method of any of the preceding clauses, wherein determining the estimate of temperature of the tissue comprises evaluating a calibration function based on calibration data and the electrical impedance, with the calibration function being a linear function, a non-linear function, or a parameterized function including data from multiple sources.

[0086] Various aspects of the disclosure may take the form of an entirely or partially hardware aspect, an entirely or partially software aspect, or a combination of software and hardware. Furthermore, as described herein, various aspects of the disclosure (e.g., systems and methods) may take the form of a computer program product comprising a computer- readable non-transitory storage medium having processor-accessible instructions (e.g., computer-readable and / or computer-executable instructions) such as computer software, encoded or otherwise embodied in such storage medium. Those instructions can be read or otherwise accessed and executed by one or more processors, individually or in combination, to perform or permit the performance of the operations described herein. The instructions can be provided in any suitable form, such as source code, compiled code, interpreted code, executable code, static code, dynamic code, assembler code, combinations of the foregoing, and the like. Any suitable computer-readable non-transitory storage medium may be utilized to form the computer program product. For instance, the computer-readable medium may include any tangible non-transitory medium for storing information in a form readable or otherwise accessible by one or more computers or processor(s) functionally coupled thereto. Non- transitory storage media can include read-only memory (ROM); random access memory (RAM); magnetic disk storage media; optical storage media; flash memory, and so forth.

[0087] Aspects of this disclosure are described herein with reference to block diagrams and flowchart illustrations of processor-implemented methods, systems, devices, apparatuses, andAttorney Docket No.: 043505.01879 APD10143PCT01 computer program products. It can be understood that each block of the block diagrams and flowchart illustrations, and combinations of blocks in the block diagrams and flowchart illustrations, respectively, can be implemented by processor-accessible instructions. Such instructions may include, for example, computer program instructions (e.g., processor-readable and / or process

[0088] or-executable instructions). The processor-accessible instructions may be built (e.g., linked and compiled) and retained in processor-executable form in one or multiple memory devices or one or many other processor-accessible non-transitory storage media. These computer program instructions also can be stored in a processor-readable memory, where in response to execution by one or more processors, individually or in combination, the computer program instructions can direct a computer, a computing device, or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the processor-readable memory produce an article of manufacture including processor-accessible instructions (e.g., processor-readable instructions and / or processor-executable instructions) to implement the function specified in the flowchart blocks (individually or in a particular combination) or blocks in block diagrams (individually or in a particular combination). The computer program instructions can be loaded onto a computer, a computing device, or other programmable data processing apparatus to cause a series of operations to be performed on the computer or other programmable apparatus to produce a computer-implemented process. The series of operations may be performed in response to execution by one or more processor or other types of processing circuitry. Thus, such instructions that execute on the computer or other programmable apparatus provide operations for implementing the functions specified in the flowchart blocks (individually or in a particular combination) or blocks in block diagrams (individually or in a particular combination).

[0089] In some implementations, the processor-accessible instructions may be loaded or otherwise incorporated into a general purpose computer, a special purpose computer, or another programmable information processing apparatus to produce a particular machine, such that the operations or functions specified in the flowchart block or blocks can be implemented in response to execution at the computer or processing apparatus. More specifically, the loaded processor-accessible instructions may be accessed and executed by one or multiple processors, individually or in combination, or other types of processing circuitry. In response to execution, the loaded processor-accessible instructions provide the functionality described in connection with flowchart blocks (individually or in a particular combination) or blocks in block diagramsAttorney Docket No.: 043505.01879 APD10143PCT01 (individually or in a particular combination). Thus, such instructions which execute on a computer, a computing device, or other programmable data processing apparatus can create a means for implementing the functions specified in the flowchart blocks (individually or in a particular combination) or blocks in block diagrams (individually or in a particular combination).

[0090] Unless otherwise expressly stated, it is in no way intended that any protocol, procedure, process, or method set forth herein be construed as requiring that its acts or steps be performed in a specific order. Accordingly, where a process or method claim does not actually recite an order to be followed by its acts or steps or it is not otherwise specifically recited in the claims or descriptions of the subject disclosure that the steps are to be limited to a specific order, it is in no way intended that an order be inferred, in any respect. This holds for any possible non-express basis for interpretation, including matters of logic with respect to the arrangement of steps or operational flow; plain meaning derived from grammatical organization or punctuation; the number or type of aspects described in the specification or annexed drawings; or the like.

[0091] As used in this disclosure, including the annexed drawings, the terms “component,” “module,” “interface,” and the like are intended to refer to a computer-related entity or an entity related to an apparatus with one or more specific functionalities. The entity can be either hardware, a combination of hardware and software, software, or software in execution. One or more of such entities are also referred to as “functional elements.” As an example, a component can be a process running on a processor, a processor, an object, an executable, a thread of execution, a program, and / or a computer. For example, both an application running on a server or network controller, and the server or network controller can be a component. One or more components can reside within a process and / or thread of execution and a component can be localized on one computer and / or distributed between two or more computers. Also, these components can execute from various computer readable media having various data structures stored thereon. The components can communicate via local and / or remote processes such as in accordance with a signal having one or more data packets (e.g., data from one component interacting with another component in a local system, distributed system, and / or across a network such as the Internet with other systems via the signal). As another example, a component can be an apparatus with specific functionality provided by mechanical parts operated by electric or electronic circuitry, which parts can be controlled or otherwise operated by program code executed by a processor. As yet another example, a component can be anAttorney Docket No.: 043505.01879 APD10143PCT01 apparatus that provides specific functionality through electronic components without mechanical parts, the electronic components can include a processor to execute program code that provides, at least partially, the functionality of the electronic components. As still another example, interface(s) can include I / O components or Application Programming Interface (API) components. Multiple components can form a system, in some cases. While the foregoing examples are directed to aspects of a component, the exemplified aspects or features also apply to a system, module, and similar.

[0092] In addition, the term “or” is intended to mean an inclusive “or” rather than an exclusive “or.” That is, unless specified otherwise, or clear from context, “X employs A or B” is intended to mean any of the natural inclusive permutations. That is, if X employs A; X employs B; or X employs both A and B, then “X employs A or B” is satisfied under any of the foregoing instances. Moreover, articles “a” and “an” as used in this specification and annexed drawings should be construed to mean “one or more” unless specified otherwise or clear from context to be directed to a singular form.

[0093] In addition, the terms “example” and “such as” are utilized herein to mean serving as an instance or illustration. Any aspect or design described herein as an “example” or referred to in connection with a “such as” clause is not necessarily to be construed as preferred or advantageous over other aspects or designs described herein. Rather, use of the terms “example” or “such as” is intended to present concepts in a concrete fashion. The terms “first,” “second,” “third,” and so forth, as used in the claims and description, unless otherwise clear by context, is for clarity only and doesn’t necessarily indicate or imply any order in time or space.

[0094] The term “processor,” as utilized in this disclosure, refers to any computing processing unit or device comprising processing circuitry that can operate on data and / or signaling. A computing processing unit or device may include, for example, single-core processors; single-processors with software multithread execution capability; multi-core processors; multi-core processors with software multithread execution capability; multi-core processors with hardware multithread technology; parallel platforms; and parallel platforms with distributed shared memory. Additionally, a processor may include an integrated circuit, an application specific integrated circuit (ASIC), a digital signal processor (DSP), a field programmable gate array (FPGA), a programmable logic controller (PLC), a complex programmable logic device (CPLD), a discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. In some cases, processors can exploit nano-scale architectures, such as molecular and quantum-Attorney Docket No.: 043505.01879 APD10143PCT01 dot based transistors, switches and gates, in order to optimize space usage or enhance performance of user equipment. A processor may also be implemented as a combination of computing processing units. In addition, or as an alternative, a processor may be implemented as a virtual machine (or virtual processor) where a host device can provide a software environment in which the virtual processor shares computing resources of the host device with other virtual processors and / or components of the host device. The software environment may be referred to as a virtualized environment and permits the virtual processor to perform operations by executing processor-executable instructions retained in a portion of the underlying computing resources. As is described herein, the computing resources may include, for example, an operating system (O / S), CPUs, memory, disk space, incoming bandwidth, and / or outgoing bandwidth.

[0095] In addition, terms such as “store,” “data store,” data storage,” “database,” and substantially any other information storage component relevant to operation and functionality of a component, refer to “memory components,” or entities embodied in a “memory” or components comprising the memory. It will be appreciated that the memory components described herein can be either volatile memory or nonvolatile memory, or can include both volatile and nonvolatile memory. Moreover, a memory component can be removable or affixed to a functional element (e.g., device, server).

[0096] Simply as an illustration, nonvolatile memory can include read only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable ROM (EEPROM), or flash memory. Volatile memory can include random access memory (RAM), which acts as external cache memory. By way of illustration and not limitation, RAM is available in many forms such as synchronous RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDR SDRAM), enhanced SDRAM (ESDRAM), Synchlink DRAM (SLDRAM), and direct Rambus RAM (DRRAM). Additionally, the disclosed memory components of systems or methods herein are intended to comprise, without being limited to comprising, these and any other suitable types of memory.

[0097] Various aspects described herein can be implemented as a method, system, device, apparatus, or article of manufacture using standard programming and / or engineering techniques. In addition, various of the aspects disclosed herein also can be implemented by means of program modules or other types of computer program instructions stored in a memory device and executed by a processor, or other combination of hardware and software, orAttorney Docket No.: 043505.01879 APD10143PCT01 hardware and firmware. Such program modules or computer program instructions can be loaded onto a general purpose computer, a special purpose computer, or another type of programmable data processing apparatus to produce a machine, such that the instructions which execute on the computer or other programmable data processing apparatus create a means for implementing the functionality of disclosed herein.

[0098] The term “article of manufacture” as used herein is intended to encompass a computer program accessible from any computer-readable device, carrier, or media. For example, computer readable media can include but are not limited to magnetic storage devices (e.g., hard drive disk, floppy disk, magnetic strips, or similar), optical discs (e.g., compact disc (CD), digital versatile disc (DVD), blu-ray disc (BD), or similar), smart cards, and flash memory devices (e.g., card, stick, key drive, or similar).

[0099] What has been described above includes examples of one or more aspects of the disclosure. It is, of course, not possible to describe every conceivable combination of components or methodologies for purposes of describing these examples, and it can be recognized that many further combinations and permutations of the present aspects are possible. Accordingly, the aspects disclosed and / or claimed herein are intended to embrace all such alterations, modifications and variations that fall within the spirit and scope of the detailed description and the appended claims. Furthermore, to the extent that one or more of the terms “includes,” “including,” “has,” “have,” or “having” is used in either the detailed description or the claims, such term is intended to be inclusive in a manner similar to the term “comprising” as “comprising” is interpreted when employed as a transitional word in a claim.

Claims

Attorney Docket No.: 043505.01879 APD10143PCT01 CLAIMS What is claimed is:

1. A system, comprising: an impedance measurement device integrated into a cutting apparatus having a cutting tool that is configured to be in contact with tissue of a subject and further configured to cut the tissue; multiple electrodes coupled with the impedance measurement device to measure electrical impedance of the tissue as the tissue is being cut, with at least one of the multiple electrodes being integrated into the cutting tool; and a control device configured to, determine, based on the electrical impedance, an estimate of temperature of the tissue as the tissue is being cut; and cause a feedback device to present an indication of the estimate of the temperature of the tissue as the tissue is being cut, with the indication being based on a deviation of the estimate of temperature of the tissue from a baseline.

2. The system of claim 1, wherein the control device is further configured to, determine that the deviation of the estimate of temperature from the baseline satisfies or exceeds a threshold value; and modify, based on the threshold value, an operation of the cutting tool. The system of any of claim 1 or 2, wherein the feedback device comprises a display device, and wherein to cause the feedback device to present the indication, the control device is configured to cause the display device to present indicia representative of the estimate of the temperature.

4. The system of any of the preceding claims, wherein the feedback device comprises a speaker device, and wherein to cause the feedback device to present the indication, the control device is configured to cause the speaker device to output at least one of an audible tone or an utterance.Attorney Docket No.: 043505.01879 APD10143PCT01 5. The system of any of the preceding claims, wherein the feedback device comprises a wearable device, and wherein to cause the feedback device to present the indication, the control device is configured to cause the wearable device to present haptic indicia.

6. The system of any of the preceding claims, wherein modifying the operation of the cutting tool comprises stopping the cutting tool.

7. The system of any of the preceding claims, wherein the multiple electrodes include a return electrode configured to couple the subject with the impedance measurement device.

8. The system of any of the preceding claims, wherein the return electrode is one of an adhesive pad configured to be mounted to a section of skin of the subject at a location that is distant to a site of the cutting tool, a lip clip, a wrist strap, a bed electrode, or an electrode in an electrocautery system.

9. The system of any of the preceding claims, wherein to determine the estimate of temperature of the tissue, the control device is further configured to evaluate a calibration function based on calibration data and the electrical impedance, with the calibration function being a linear function, a non-linear function, or a parameterized function including data from multiple sources.

10. The system of any of the preceding claims, wherein the calibration data comprises one or more of factory calibrated data, data personalized to the subject, or data generated with a subject-specific calibration.

11. A computing device comprising: one or more processors; one or more memory devices having processor-executable instructions stored thereon that, in response to execution by the one or more processors, individually or in combination, cause the computing device at least to, obtain, as tissue of a subject is being cut using a cutting apparatus having a cutting tool, an impedance measurement signal indicative of electrical impedance of the tissue of the subject;Attorney Docket No.: 043505.01879 APD10143PCT01 determine, based on the electrical impedance, an estimate of temperature of the tissue as the tissue is being cut; and cause a feedback device to present an indication of the estimate of the temperature of the tissue as the tissue is being cut, with the indication being based on a deviation of the estimate of temperature of the tissue from a baseline.

12. The computing device of claim 11, the one or more memory devices having further processor-executable instructions stored thereon that, in response to execution by the one or more processors, individually or in combination, further cause the computing device to, determine that the deviation of the temperature from the baseline satisfies or exceeds a threshold value; and modify, based on the threshold value, an operation of the cutting tool.

13. The computing device of any of claim 11 or 12, wherein the feedback device comprises a display device, and wherein causing the feedback device to present the indication comprises causing the display device to present indicia representative of the estimate of the temperature.

14. The computing device of any of the preceding claims, wherein modifying the operation of the cutting tool comprises stopping the cutting tool.

15. The computing device of any of the preceding claims, wherein determining the estimate of temperature of the tissue comprises evaluating a calibration function based on calibration data and the electrical impedance, with the calibration function being a linear function, a non-linear function, or a parameterized function including data from multiple sources.

16. A method comprising: obtaining, as tissue of a subject is being cut using a cutting apparatus having a cutting tool, an impedance measurement signal indicative of electrical impedance of the tissue of the subject; determining, based on the electrical impedance, an estimate of temperature of the tissue as the tissue is being cut; andAttorney Docket No.: 043505.01879 APD10143PCT01 causing a feedback device to present an indication of the estimate of the temperature of the tissue as the tissue is being cut, with the indication being based on a deviation of the estimate of temperature of the tissue from a baseline.

17. The method of claim 16, further comprising: determining that the deviation of the estimate of temperature from the baseline satisfies or exceeds a threshold value; and modifying, based on the threshold value, an operation of the cutting tool.

18. The method of any of claim 16 or 17, wherein the feedback device comprises a display device, and wherein causing the feedback device to present the indication comprises causing the display device to present indicia representative of the estimate of the temperature.

19. The method of any of the preceding claims, wherein modifying the operation of the cutting tool comprises stopping the cutting tool.

20. The method of any of the preceding claims, wherein determining the estimate of temperature of the tissue comprises evaluating a calibration function based on calibration data and the electrical impedance, with the calibration function being a linear function, a non- linear function, or a parameterized function including data from multiple sources.

Images