Identifying and assessing tissue type and nerve health

Abstract

Provided is a device and a method of assessing anatomy and nerve health, which may include using impedance measurements to distinguish tissue types, locate damaged nerve tissue, and provide information regarding the health of nerve tissue

Description

TITLEIDENTIFYING AND ASSESSING TISSUE TYPE AND NERVE HEALTHCROSS REFERENCE TO RELATED APPLICATIONS

[0001] The application claims priority to U.S. Patent Application No. 63 / 544,981, filed on October 20, 2023, entitled “ASSES SING NERVE HEALTH,” which is incorporated herein by reference in its entirety.TECHNICAL FIELD

[0002] The present disclosure is generally related to devices and methods of detecting nerve health, and more particularly, a device and a method of using measurements of tissue properties such as conduction and complex impedance to detect tissue type and nerve health.BACKGROUND

[0003] Peripheral nerve injuries are diagnosed in upper extremity trauma patients and lower extremity trauma patients in the Unites States. Distinguishing between tissue types and establishing nerve health can be extremely difficult with current tools. The current "gold standard" for assessing nerve injury are Electromyography (EMG), nerve conduction studies (NCS), and physical clinical examination. Electromyography and nerve conduction studies are powerful tools which are often combined with clinical examinations to evaluating nerve health under classifications systems such as Seddon Classification injuries (Neuropraxia, Axonotmesis, Neurotmesis, etc.). However, these measurement techniques each have technical and practical limitations that impact clinical utility and decision making.

[0004] Electromyography can be used to evaluate the function of motor nerves and their innervated muscles, but the measures have limitations in specificity and sensitivity, which impacts the ability to quantify nerve health. These limitations are further confounded by physiologic and neuromotor redundancies, which provide resilience to injury or disease but complicate the direct correlation of an electrodiagnostic measure to functional capacity. Similarly, nerve conduction measures provide insight into if and how well the nerve is conducting an action potential but lacks sensitivity to further differentiate within injury severity. These current techniques provide a snapshot of current nerve and muscle function, providing the most predictive information when serial tests are completed to compare measures over time to track recovery or injury progression. Repeated measures are not always possible, and if done, the additional time delay before intervention further reduces the likelihood of full recovery.

[0005] Traditional electrodiagnostic measures, such as nerve conduction, electromyography, and compound muscle action potentials, are also technologically burdensome requiring complex equipment and training to accurate and reliable measurements. The operative environment further complicates the use of electrodiagnostic measures to identify and evaluate nerves for surgical decision making. These measures are highly susceptible to artifacts and noise, with the operative time constraints reducing the ability to complete multiple measurements for signal averaging. As equipment is located both within and outside of the sterile field, operative use of electrodiagnostic testing requires collaboration and coordination between the technician and the surgeon. These practical and physiologic limitations of current electrodiagnostic techniques, presents an opportunity for new techniques better suited to provide a measure of nerve structure or function to improve surgical decision making.

[0006] As a result, there is a need for devices, systems, and methods that can provide accurate and reliable results for assessing anatomy and nerve health from a patient.SUMMARY

[0007] The following presents a summary of this disclosure to provide a basic understanding of some aspects. This summary is intended to neither identify key or critical elements nor define any limitations of embodiments or claims. Furthermore, this summary may provide a simplified overview of some aspects that may be described in greater detail in other portions of this disclosure. Any of the described aspects may be isolated or combined with other described aspects without limitation to the same effect as if they had been described separately and in every possible combination explicitly.

[0008] The present disclosure relates to a novel method and apparatus measuring electrical complex impedance of a target tissue to information regarding tissue type, structure, and / or function. The electrochemical and physiologic processes of peripheral nerves enable the use of an impedance to provide both a structural and functional measure of the peripheral nerve. This measure of structure and or function can be used to provide insight into the health of the nerve without the need to directly measure a nerve action potential or evoked el ectromy ography .

[0009] Tissue impedance may be expressed as the complex impedance with a magnitude and phase, real and imaginary component, or separate components. The measure may be expressed across a range of testing frequencies or assessed at one or more defined frequencies. These frequencies or ranges of frequencies may be optimized for the specific application or measurement being taken. For example, to aid in locating nerve tissue, the measurement may be conducted at a frequency and other parameters where the nerve tissue measurements are distinct from the measurements of surrounding tissues, such as muscle, adipose, vessels, or scar. Testing frequency may be altered to evaluate different tissue characteristics, such as the underlying nerve structure and function of the nerve.

[0010] The electrochemical processes within a nerve enables the use of electrical impedanceas a measure of both nerve structure and function. Under normal conditions, nerves propagate the action potential using ion channels including sodium and potassium ion channels. These channels actively control the polarization of the nerve, and thus impact the electrical characteristics of the nerve tissue. As a peripheral nerve is comprised of multiple individual axons, impedance can provide a structural measure of the number of axons within a nerve. This structural measurement can be used to quantify internal changes, such as the development of scar tissue within the nerve or the loss of axon continuity when the epineurium continuity is intact. Furthermore, on myelinated axons the myelin sheath acts as an insulator to speed action potential conduction along the axon. Loss of this myelin sheath, which impairs axon function, can be measured by evaluating the tissue impedance to provide a measure of both structure and function. Impedance can be used to track the process of nerve regeneration or repair, quantifying structural and functional changes as the axons reconnect to the target endpoints. Changes in axon conductance due to local demyelination, axon loss, etc., would alter the measured impedance and thus provide insight into nerve structure and function. This measure provides the potential to detect and grade nerve injury severity, such as loss of axonal continuity versus focal demyelination or the number of intact axons within a nerve, and can inform surgical decision making on the optimal surgical intervention.

[0011] Impedance provides advantages over current electrodiagnostic techniques, which makes it well suited for use in the operating room. Since impedance is measured across a target tissue, it does not rely on the direct measurement of an evoked muscle response or nerve action potential. Signal to noise ratio is greatly improved, reducing technological complexity. Removing the need for an observed or measured motor response enables location and assessment of sensory nerves and transected nerves in addition to intact motor nerves. The measurement parameters, e.g. frequency, can be tuned for the structural or functional characteristic being evaluated to improve measurement selectivity and sensitivity. Forexample, the parameters can initially set to optimize nerve localization for the initial part of the procedure then adjusted to optimize nerve assessment.

[0012] Disclosed is a method of using complex impedance measurements to characterize tissue. In an embodiment, the method comprises wherein a complex impedance measurement is presented as relative number compared to a previous measurement. In an embodiment, the method comprises wherein the device presents the measurement as a qualitative indication of complex impedance relative to a previous measurement. In an embodiment, the method comprises using complex impedance measurements to locate damaged nerve tissues. In an embodiment, the method comprises using complex impedance measurements to distinguish tissue types. In an embodiment, the method comprises using complex impedance to measure, assess, and provide information regarding the health of nerve tissue.

[0013] Disclosed is a probe apparatus for conducting Kelvin style complex impedance measurements on a nerve. In an embodiment, the probe circumferentially insulates and constrains the nerve. In an embodiment, the probe includes window or slot to visualize the nerve. In an embodiment, the probe is biased to a closed position to minimize risk to the nerve during movement along the length of the nerve. In an embodiment, the probe comprises individual contacts that are spring loaded. In an embodiment, the contacts are printed on a flexible substrate. In an embodiment, the probe comprises a plurality of contacts used to assess impedance at multiple points on the nerve. In an embodiment, the plurality of contacts may be multiplexed or switched between sourcing and sensing measurement to allow a 4-wire impedance measurement at multiple points on the nerve.

[0014] Disclosed is an implantable electrode. In an embodiment, the electrode comprises an electrode body, a lead connection, and a plurality of contacts for conducting a Kelvin style complex impedance measurement on a nerve. In an embodiment, the plurality of contacts and electrode body are bioabsorbable and the lead connection is retractable percutaneously throughthe skin. In an embodiment, the indication output is via a built in display. In an embodiment, the indication output is via a remote display. In an embodiment, the indication output is via a generation of an audio tone. In an embodiment, the sourcing and sensing electrodes are the same. In an embodiment, the sourcing and sensing electrodes are two distinct pairs. In an embodiment, the sourcing and sensing electrodes are multiplexed across 3 or more electrodes spaced along the axial length of a nerve probe.

[0015] Disclosed is a nerve measurement system. In an embodiment, the system comprises a probe with 2 or more contacts each allocated to a sourcing or sensing functionality, control circuitry generating an excitation signal via designated source electrodes, measurement circuitry connected to a set of sensing electrodes, data storage, an input control for identifying the baseline measurement, and an indication output for indicating the relative measurement.

[0016] A method may comprise measuring complex impedance present in tissue and characterizing health of the tissue from the measuring of complex impedance.

[0017] The method may also comprise a second measuring of complex impedance present in the tissue wherein the second measuring of complex impedance is presented as a relative number compared to the measuring of complex impedance.

[0018] A device may present the second measuring complex impedance as a qualitative indication of complex impedance relative to the measuring complex impedance.

[0019] A method may comprise measuring complex impedance present in tissue and characterizing of the tissue based on the measuring of complex impedance.

[0020] A method may comprise measuring complex impedance present in tissue and characterizing a type of tissue of the tissue from the measuring of complex impedance.

[0021] A probe for conducting Kelvin style complex impedance measurements on a nerve, wherein the probe comprises an arm that circumferentially insulates and constrains the nerve. The probe may also comprise a window or slot to visualize the nerve and / or a second arm,wherein the arm and the second arm are biased to a closed position to minimize risk to the nerve during movement along a length of the nerve, and / or a pair of individual contacts on the arm that are spring loaded, and / or at least one contact printed on a flexible substrate of an arum, and / or a plurality of contacts used to assess impedance at multiple points on the nerve. The plurality of contacts are multiplexed or switched between sourcing and sensing measurement to allow a 4-wire impedance measurement at multiple points on the nerve.

[0022] An implantable electrode may comprise an electrode body, one or more lead connections, and a plurality of contacts for conducting a Kelvin style complex impedance measurement on a nerve. The plurality of contacts and the electrode body are bioabsorbable and the lead connections are retractable percutaneously through skin.

[0023] A nerve measurement system may comprise a probe with two or more contacts each allocated to a sourcing or sensing functionality, control circuitry generating an excitation signal via designated source electrodes, measurement circuitry connected to a set of sensing electrodes and data storage. The nerve measurement system may also comprise an input control for identifying a baseline measurement and an indication output for indicating relative measurement. The nerve measurement system may comprise the indication output is via a built in display, and / or the indication output is via a remote display, and / or the indication output is via a generation of an audio tone, and / or the sourcing and sensing electrodes are the same, and / or the sourcing and sensing electrodes are two distinct pairs, and / or the sourcing and sensing electrodes are multiplexed across three or more electrodes spaced along an axial length of a nerve probe.

[0024] The following description discloses various illustrative aspects. Some improvements and novel aspects may be expressly identified, while others may be apparent from the description and drawings.BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The present teachings may be better understood by reference to the following detailed description taken in connection with the following illustrations, in which like reference characters refer to like parts throughout, wherein:

[0026] FIG. 1 shows an embodiment of a device for identifying and assessing nerve tissue (e.g., by measuring impedance) in accordance with aspects disclosed herein;

[0027] FIG. 2 shows an embodiment of a device for identifying and assessing nerve tissue (e.g., by measuring impedance) in accordance with aspects disclosed herein;

[0028] FIG. 3 shows an embodiment of a distal tip of a device for identifying and assessing nerve tissue (e.g., by measuring impedance) in accordance with aspects disclosed herein;

[0029] FIG. 4 shows an embodiment of a device for identifying and assessing nerve tissue (e.g., by measuring impedance) in accordance with aspects disclosed herein;

[0030] FIGs. 5-8 show an embodiment of a device, and selectively separable components thereof, for identifying and assessing nerve tissue (e.g., by measuring impedance) in accordance with aspects disclosed herein;

[0031] FIG. 9 shows an embodiment of a system including a device for identifying and assessing nerve tissue (e.g., by measuring impedance) relative a patient’s arm in accordance with aspects disclosed herein;

[0032] FIG. 10 shows an schematic representation of a configuration of contacts in a distal tip of a device for measuring impedance in accordance with aspects disclosed herein.

[0033] The invention may be embodied in several forms without departing from its spirit or essential characteristics. The scope of the invention is defined in the appended claims, rather than in the specific description preceding them. All embodiments that fall within the meaning and range of equivalency of the claims are therefore intended to be embraced by the claims.DETAILED DESCRIPTION

[0034] Reference will now be made in detail to exemplary embodiments of the presentdisclosure. It is to be understood that other embodiments may be utilized, and structural and functional changes may be made without departing from the scope of the present disclosure. Moreover, features of the various embodiments may be combined or altered without departing from the scope of the present disclosure. As such, the following description is presented by way of illustration only and should not limit in any way the various alternatives and modifications that may be made to the illustrated embodiments and still be within the spirt and scope of the present disclosure.

[0035] In this disclosure, numerous specific details provide a thorough understanding of the subject disclosure. It should be understood that aspects of this disclosure may be practiced with other embodiments not necessarily including all aspects described herein, etc.

[0036] As used herein, the words “example” and “exemplary” mean an instance, or illustration. The words “example” or “exemplary” do not indicate a key or preferred aspect or embodiment. The word “or” is intended to be inclusive rather an exclusive, unless context suggests otherwise. As an example, the phrase “A employs B or C,” includes any inclusive permutation (e.g., A employs B; A employs C; or A employs both B and C). As another matter, the articles “a” and “an” are generally intended to mean “one or more” unless context suggests otherwise.

[0037] Further, as herein disclosed, the terms “substantially,” “about,” and variations thereof describe features that are equal or approximately equal to a value or characteristic, as desired, reflecting tolerances, conversion factors, rounding off, measurement error, acceptable variation thresholds, and the like. For example, unless context or this disclosure suggests otherwise, the term “substantially” includes values or characteristics that are exact or within 15% of exact (or what is stated), for example within 10% of exact, or within 5% of exact. In another example, unless context or this disclosure suggests otherwise, the term “about” includes values within .5 of a degree to 1 degree of exact (or what is stated).

[0038] Further, unless context or this disclosure suggests otherwise, descriptions of shapes (e.g., circular, rectangular, triangular, etc.) refer to shapes meeting the definition of such shapes and general representation of such shapes. For instance, a triangular shape or generally triangular shape may include a shape that has three sides and three vertices or a shape that generally represents a triangle, such as a shape having three major sides that may or may not have straight edges, triangular like shapes with rounded vertices, etc.

[0039] The present disclosure relates to devices, systems, and methods of using impedance to characterize tissue structure, type, and / or composition. As described herein, impedance can be used as a measure of peripheral nerve structure and function as a means to quantify or assess nerve health. The following description illustrates non-limiting examples of: applications of the disclosed devices, systems, and methods; a sensing model; methods and apparatuses for sensing; methods of sensing nerve health; methods of distinguishing tissue types; example features of the apparatus / device; and the like.

[0040] As described herein, different tissues in the human body vary in composition, and this difference in composition is manifested in different properties of each tissue type including, for example, in the electrical properties of different tissue types (e.g., nerve, muscle, tendon, connective tissue etc.). The devices, systems, and methods of the present disclosure utilize and measure the resulting variations in impedance and complex impedance to distinguish tissue types or changes in the tissue characteristics, which can be used to find and assess nerves and nerve health, for example.

[0041] The devices, systems, and methods of the present disclosure, and measured impedance using the foregoing, can be used to probe different tissue types (e.g., nerve, muscle, tendon, connective tissue etc.), and determine if it is nerve tissue. For example, the devices, systems, and methods of the present disclosure can be used to assess tissue of an unknown type (e.g., unknown to the presence and location of nerve tissue) to identify nerve tissue, if present, anddetermine the location of the nerve tissue. In an embodiment, the devices, systems, and methods of the present disclosure allows the identification of nerve tissue without direct measurement or observation of a motor response or action potential. This is particularly useful during a surgical procedure.

[0042] As such, sensory nerves or transected motor nerves without connection to a target muscle (e.g., by degradation or injury) can be localized and assessed based upon impedance using the devices, systems, and methods of the present disclosure. Differences in the measured impedances determined the devices, systems, and methods of the present disclosure can be used to identify the tissue of interest for confirmation of localization prior to visualization. The disclosed devices, systems, and methods measuring and using impedance as disclosed herein can be used to probe and identify different tissue types (e.g., nerve, muscle, tendon, connective tissue etc.).

[0043] In an embodiment, the impedance value may be directly reported to the user as a number, graphical output, or visualized image or color bar. In an embodiment, the impedance value may be provided to the user on the device or other component of the system, e.g., by integrated visual indicators such as a light, on an integrated display screen, or the like, or the impedance value may be provided to the user on an independent or separate screen or remotely, for example, through wireless connection such as Bluetooth, Wi-Fi, or the like. It is further noted that auditory and other indicators are also herein contemplated and may be used with any of the disclosed devices, systems, and methods. In an embodiment, impedance may be reported as an absolute measured value, or provided as a differential based on a reference value, historical value, or an initial measurement or calibration done on each procedure or surgical site. The measurement range or parameters may be adjustable or adjusted based on the tissue to be identified, e.g. nerve compared to muscle. The devices, systems, and methods of the present disclosure may be used to actively probe and follow the paths of distinct tissuesintraoperatively. Various tissue types including tendon, nerve, vessel, connective tissue and muscle tissue can be measured, categorized, and / or identified to aid health care professionals in surgery using the disclosed devices, systems, and methods.

[0044] The devices, systems, and methods of the present disclosure, and measured impedance using the foregoing, can be used as a measure of nerve structure and function to provide an intraoperative evaluation of nerve health. As the primary function of the nerve is to conduct or transfer action potentials from the cell body to the terminal synapse, changes in impedance (reduction in conductance) would signal altered nerve function. Structural differences in impedance may also reflect loss of axons within the nerve, or changes in axon structure, such as loss of the myelin sheath that helps to speed nerve conduction. By measuring complex impedance using the devices, systems, and methods described herein, the location, severity of nerve injury, and or structural changes may be evaluated intraoperatively.

[0045] In an embodiment, the impedance may be reported as an absolute value, compared to other areas on the same nerve, or compared to other nerve tissue in the same individual. These measurements can be used to quantify structural and functional changes within the nerve as a proxy of nerve health. In an embodiment, impedance can be measured at different point along the nerve to help a surgeon locate and confirm the precise position of a nerve injury. Measures of impedance using the disclosed devices, systems, and methods can be done across areas of the nerve, including across or through an area of suspected nerve injury or damage to evaluate the tissue health or function. This measurement can be compared to reference norms or compared to a relative measurement of impedance of a known healthy or un-injured portion of the nerve. The impedance of the two locations can be compared to provide a measure of structural or functional changes, such as number of axons, myelination of the nerve, etc.

[0046] These measurements taken by the disclosed devices systems and methods may be reported as a value or relative percentage, for example, based on reference data, historical datafor the patient, and the like. In an embodiment, the past and current measurements may be saved locally or transmitted to a server for storage to be reported or displayed to the user. The display can include providing the data in a visual form, including as a graph, table, or bar. In an embodiment, the stored data may be evaluated to provide trends over time (e.g., across different measurements taken of the patient) to assess nerve heath over time.

[0047] Turning to FIGs. 1-10, shown are several embodiments of devices for measuring impedance and identifying and assessing nerve health as described herein. FIG. 9 further shows a system of the present disclosure including an external impedance measuring device that may be used with any of the foregoing embodiments of devices shown in FIGs. 1-10 and described herein. It is noted that the described system may be used with an adaptor to connect to any other device or system as may be suitable or desired for a particular purpose. The following are non-limiting examples of devise, systems, and methods according to the present disclosure.

[0048] For example, shown in FIG. 1 is device or probe 100. As described herein, device 100 may be used to measure impedance of a tissue site and may facilitate the identification of nerve tissue and the assessment of nerve health. In an embodiment, device 100 may generally include a first end or distal end 110 and a second or proximal end 120. Device 100 may further include body 130 between the distal end 110 and the proximal end 120. In an embodiment, the device 100 or body 130 may generally include a first arm 142 and a second arm 152. In an embodiment, the first arm 142 and the second arm 152 may connect to one another and terminate at or form the proximal end 120. The first arm 142 and the second arm 152, and the proximal end 120, may form a point at the proximal end 120. From the proximal end 120, the first arm 142 and the second arm 152 may be angled and extend away from one another. For example, the first arm 142 and the second arm 152 may extend at a 30°, 45°, 60° angle, etc. from one another from the proximal end 120. It is noted that the first arm 142 and the second arm 152 may be positioned at any angle relative one another as may be desired or suitable fora particular purpose, for example, any value or range including and within 15°-70°.

[0049] In an embodiment, device 100 and each arm 142, 152 may further include a point or section 146, 156 where each arm 142, 152 turns inward or toward one another toward the distal end 110 of the device 100. For example, each the first arm 142 and the second arm 152 may extend at a 100°, 120°, 140° angle, etc. at the point or section 146, 156 relative the corresponding section proximal the point or section 146, 156 (e.g., toward the proximal end 120). It is noted that the point or section 146, 156 of the first arm 142 and the second arm 152 respectively may comprise any angle as may be desired or suitable for a particular purpose, for example, any value or range including and within 100°-165°. It is noted that each arm 142, 152 may have the same angled shape or mirrored angle shapes, or each arm 142, 152 may have a different shape, e.g., position of point 146, 156 on arm 142, 152, angles thereof, and the like.

[0050] In an embodiment, distal end 110 may comprise a cuff. The cuff may be formed by planar faces 144, 154 that extend from each corresponding arm 142, 152 respectively. In an embodiment, the first arm 142 and the second arm 152 may cross between the points or sections 146, 156 and the planar faces 144, 154 of the distal end 110. For example, the first arm 142 may comprise a slot 148 formed within the first arm 142 between point or section 146 and planar face 144. The slot 148 may be sized and shaped to selectively receive a corresponding section 158 on the second arm 152 between point or section 156 and planar face 154. For example, section 158 may taper or narrow to slide within slot 148 or slot 148 may increase or widen to receive section 158 therethrough. It is noted that section 158 may contact side walls of slot 148 or section 158 may be narrower so that section 158 does not contact side walls of slot 148. In an embodiment, the second arm 152 may cross through the first arm 142. In an embodiment, section 158 of the second arm 152 may cross through slot 148 of the first arm 142. In an embodiment, the crossing of arms may selectively open and close the planar faces144, 154 and selectively expose the electrical contacts 192 therebetween as described herein.

[0051] As a result, planar face 154 of the second arm 152 may be on an opposite side of the device 100 from the remaining portion of the second arm 152. Similarly, planar face 144 of the first arm 142 may be on an opposite side of the device 100 from the remaining portion of the first arm 142. For example, planar face 154 of second arm 152 may be on the same side of the device 100 as the first arm 142 (e.g., the section of first arm 142 proximal point 146 and excluding the planar face 144 of first arm) and planar face 144 of first arm 142 may be on the same side of the device 100 as the second arm 152 (e.g. the section of second arm 152 proximal point 156 and excluding the planar face 154 of second arm).

[0052] In an embodiment, the first arm 142 and the second arm 152 may be squeezed towards one another by a user, e.g., on the sections proximal the points 146, 156, which may then separate the planar faces 144, 154 from one another or otherwise open the cuff at the distal end 110 of device 100 as the section 158 of the second arm 152 slides through the slot 148 of first arm 142. In an embodiment, the device 100 may be biased toward a closed position of the cuff where the planar faces 144, 154 of each arm 142, 152 are in contact with each other. When force is applied to the device 100, cuff may be opened and the planar faces 144, 154 separated. The device 100 and proximal end 120 thereof may comprise any suitable material such as biocompatible, rigid or semirigid materials such as polypropylene, polycarbonate, acrylonitrile butadiene styrene (ABS), polyamide (nylon), silicone, urethane, etc., as may be desired to allow flexibility and movement when a force is applied thereon and which will return to its shape when the force is removed. In an embodiment, the device 100 may have the tension and movement similar to a tweezer.

[0053] In an embodiment, the distal end 110 or planar faces 144, 154 of device 100 may include electrical contacts or electrodes 192 on an interior side of the faces / cuff When the distal end110 or cuff is in a forced open position with the planar faces 144, 154 separated, electricalcontacts or electrodes 192 on the cuff and the planar faces 144, 154 may be exposed. In an embodiment, when the distal end 110 or cuff is in a forced open position with the planar faces 144, 154 separated, device 100 may be positioned so that tissue may be placed within the distal end 110 or cuff and between the planar faces 144, 154, in contact with the electrical contacts or electrodes 192. The force may be released from the device 100 with the tissue positioned therein so that the electrical contacts or electrodes 192 are in contact with the tissue and the device 100 may generally remain locked in place with the biased tension of the device 100 to a closed position. When the force is reapplied, the device 100 may reopen and be moveable to a different area of tissue. In an embodiment, device 100 may be referred to or function as a resting or biased to closed probe. In an embodiment, one or both planar faces 144, 154 may comprise a window or slot 194 so that tissue positioned in between the planar faces 144, 154 may be visible and to allow visualization of the target tissue.

[0054] In another example, shown in FIG. 2 is device or probe 200. As described herein, device 200 may be used to measure impedance of a tissue site and may facilitate the identification of nerve tissue and the assessment of nerve health. In an embodiment, device 200 may generally include a first end or distal end 210 and a second or proximal end 220. Device 200 may further include body 230 between the distal end 210 and the proximal end 220. In an embodiment, the device 200 or body 230 may generally include a first arm 242 and a second arm 252. In an embodiment, the first arm 242 and the second arm 252 may connect to one another and terminate at or form the proximal end 220. The first arm 242 and the second arm 252, and the proximal end 220, may form a point at the proximal end 220. From the proximal end 220, the first arm 242 and the second arm 252 may be angled and extend away from one another. For example, the first arm 242 and the second arm 252 may extend at a 15°, 30°, 45°, 60° angle, etc. from one another from the proximal end 220. It is noted that the first arm 242 and the second arm 252 may be positioned at any angle relative one another as may be desired orsuitable for a particular purpose, for example, any value or range including and within 5°-70°.

[0055] In an embodiment, device 200 and each arm 242, 252 may widen or curve away from one another at the distal end 210 of the device 200 to provide a cuff formed by curved faces 244, 254 of corresponding arms 242, 252. Compared to device 100, the entire length of the arms 242, 252 of the device 200 may remain on the same side of the device 200, whereas the arms 142, 152 of device 100 crossed and intersected one another. As with device 100, the first arm 242 and the second arm 252 may be squeezed towards one another by a user, e.g., on body 230. But when such force is applied to device 200, with the arms 242, 252 not crossing one another, the curved faces 244, 254 may move towards one another, e.g., until the curved faces 244, 254 come into contact or nearly come into contact.

[0056] In an embodiment, the device 200 may be biased toward an open position of the cuff where the curved faces 244, 254 of each arm 242, 252 are separated from each other. When force is applied to the device 200, cuff may move toward a closed position and the curved faces 244, 254 move in closer proximity to one another. The device 200 and proximal end 120 thereof may comprise any suitable material such as biocompatible, rigid or semirigid materials such as polypropylene, polycarbonate, acrylonitrile butadiene styrene (ABS), polyamide (nylon), etc., as may be desired to allow flexibility and movement when a force is applied thereon and which will return to its shape when the force is removed. In an embodiment, the device 200 may have the tension and movement similar to a tweezer.

[0057] In an embodiment, the distal end 210 or curved faces 244, 254 of device 200 may include electrical contacts or electrodes 292 on an interior side of the faces / cuff When the distal end 210 or cuff is in a resting open position with the curved faces 244, 254 separated, electrical contacts or electrodes 292 on the cuff and the curved faces 244, 254 may be exposed. In an embodiment, when the distal end 210 or cuff is in a resting open position with the curved faces 244, 254 separated, device 200 may be positioned so that tissue may be placed within thedistal end 210 or cuff and between the curved faces 244, 254, in contact with the electrical contacts or electrodes 292. A force may be applied to the device 200 with the tissue positioned therein so that the electrical contacts or electrodes 292 are in close contact with the tissue. When the force is released, the device 200 may reopen with the biased tension of the device 200 to an open position and be moveable to a different area of tissue. In an embodiment, device 300 may be referred to or function as a resting or biased to open probe. In an embodiment, one or both curved faces 244, 254 may comprise a window or slot so that tissue positioned in between the curved faces 244, 254 may be visible and to allow visualization of the target tissue.

[0058] FIG. 2 further shows a device or probe 300. As described herein, device 300 may be used to measure impedance of a tissue site and may facilitate the identification of nerve tissue and the assessment of nerve health. In an embodiment, device 300 may generally include a first end or distal end 310 and a second or proximal end 320 (note that FIG. 3 shows only a portion of the proximal end 320 and that the proximal end 320 may have any shape or configuration as may be desired or suitable for a particular purpose). Device 300 may further include body 330 between the distal end 310 and the proximal end 320. In an embodiment, the device 300 or distal end 310 may generally include a first stationary face 344 and a second stationary face 354. Compared to devices 100, 200, device 300 may not include arms except for the stationary faces 344, 354 and these arms or faces may extend or be located only at the distal end 310 of the device 300 and the body 330 may be a singular elongated form.

[0059] Compared to devices 100, 200, device 300 may include stationary faces 344, 354 that are immovable or stationary and that are provided in an open position so that there is space between the faces 344, 354 forming a cuff. In an embodiment, the faces 344, 354 may be planar. Like devices 100, 200, the distal end 310 or stationary faces 344, 354 of device 300 may include electrical contacts or electrodes 392 on an interior side of the faces / cuff In an embodiment, device 300 may be positioned so that tissue may be placed within the distal end 310 or cuff andbetween the stationary faces 344, 354, in contact with the electrical contacts or electrodes 392. In an embodiment, one or both stationary faces 344, 354 may comprise a window or slot so that tissue positioned in between the stationary faces 344, 354 may be visible and to allow visualization of the target tissue.

[0060] Turning to FIGs. 3-4, shown is a device or probe 400. As described herein, device 400 may be used to measure impedance of a tissue site and may facilitate the identification of nerve tissue and the assessment of nerve health. In an embodiment, device 400 may generally include a first end or distal end 410 and a second or proximal end 420. Device 400 may further include body 430 between the distal end 410 and the proximal end 420. Compared to devices 100, 200, 300, device 400 may not include two faces or arms that face one another and form a space therebetween to provide a cuff. In an embodiment, the device 400 or distal end 410 may generally include a header or protrusion 412. In an embodiment, the device 400 or distal end 410 may generally include a singular header or protrusion 412. In an embodiment, the header or protrusion 412 may be planar. In an embodiment, the header or protrusion 412 may be axial the body 430. In an embodiment, the header or protrusion 412 may be stationary.

[0061] Like devices 100, 200, 300, the distal end 410 of device 400 may include electrical contacts or electrodes 492. Compared to devices 100, 200, 300 where the electrical contacts or electrodes may be positioned on an interior side of the faces / cuff, protrusion 412 on the device 400 may include tip 414 including the electrical contacts or electrodes 492. In an embodiment, device 400 may be positioned so that tissue may be in contact with the distal end 410 or tip 414 and in contact with the electrical contacts or electrodes 492. In an embodiment, the electrical contacts or electrodes 492 may be spring-loaded, see FIG. 4, for example.

[0062] Turning to FIGs. 5-8 shown is device or probe 500, including components lead body 505 and flexible or circuit electrode 555. In an embodiment, the lead body 505 shown in FIGs. 5-6 and the flexible electrode 555 shown in FIG. 7 may be selectively coupled to one another,see FIG. 8. For example, the flexible electrode 555 may be inserted into a corresponding channel 540 of the lead body 505 that is sized and shaped to receive the flexible electrode 555. In an embodiment, the flexible electrode 555 may be held in position within the lead body 505 by friction fit, snap-fit, bayonet attachment, corresponding recesses and protrusions, and the like. In an embodiment, the lead body 505 and the flexible electrode 555 may be axially aligned with one another and form a singular elongated body when selectively and / or electrically coupled to one another.

[0063] As described herein, device 500 may be used to measure impedance of a tissue site and may facilitate the identification of nerve tissue and the assessment of nerve health. In an embodiment, device 500 may generally include a first end or distal end and a second or proximal end. Device 500 may further include body between the distal end and the proximal end. Similarly, each of lead body 505 and flexible electrode 555 may include corresponding distal ends, proximal ends, and bodies, which may generally form or otherwise align with or be in the same orientation as the distal and proximal ends of device 500.

[0064] In an embodiment, lead body 505 may include a distal end 510, a proximal end 520, and an elongated body 530. In an embodiment, the distal end 510 may include a header 513 having a griping protrusion 517 and a retaining protrusion 519. In an embodiment, the gripping protrusion 517 may be curved (e.g., like a spiral or portion of a spiral) and may extend toward a first direction (e.g., to an underside of the lead body 505). In an embodiment, the retaining protrusion 519 may be curved (e.g., like a spiral or portion of a spiral) and may extend toward a second direction (e.g., to a topside of the lead body 505). In an embodiment, the first direction and the second direction may be in opposite or almost opposite directions.

[0065] In an embodiment, the distal end 510 may further include an interior retaining wall 518 that forms a cavity with retaining protrusion 519. Together, the retaining protrusion 519 and the interior retaining wall 518 may hold the desired tissue or nerve therebetween and facilitatecontact with the flexible electrode 555. In an embodiment, the interior retaining wall 518 may also assist in securing the flexible electrode 555 within the lead body 505. In an embodiment, the interior retaining wall 518 may be generally straight and have a free or unconnected distal edge. In an embodiment, the interior retaining wall 518 may be located in or form channel 540, or a portion of channel 540 thereof.

[0066] In an embodiment and as described herein, the lead body 505 may comprise a soft or flexible material, including one or more (or all of) the griping protrusions 517, the interior retaining wall 518 and the retaining protrusions 519 to allow movement away from and toward the lead body 505 to interact with intended tissue.

[0067] For example, the gripping protrusion 517 may facilitate gripping into surrounding tissue when lead body 505 is inserted into a patient. For example, the retaining protrusion 519 may facilitate retaining a portion of tissue or nerve therein to provide contact with and proximity to electrical contacts or electrodes on the flexible electrode 555. As described herein, lead body 505 may further include a retaining channel 540. The retaining channel 540 may be sized and shaped to receive flexible electrode 555.

[0068] In an embodiment, flexible electrode 555 may include a distal end 560, a proximal end 570, and an elongated body 580. The distal end 560 may include electrical contacts or electrodes 562. The proximal end 570 may include a connector 572, e.g., selectively connectable to a handheld device, such as an external impedance measuring device. In an embodiment, the flexible electrode 555 may insert into lead body 505 so that the distal end 560 of the flexible electrode 555 is adjacent, near, or in proximity to the retaining protrusion 519 on the distal end 510 of lead body 505. In an embodiment, tissue may be in contact with and held by retaining protrusion 519 and interior retaining wall 518 so that the tissue is also against electrical contacts or electrodes 562.

[0069] Turning to FIG. 9, shown is a device or probe 600. As described herein, device 600may be used to measure impedance of a tissue site and may facilitate the identification of nerve tissue and the assessment of nerve health. In an embodiment, the device 600 may include a bio- absorbable lead 610, wherein at least a portion of the lead 610 may be bio-absorbable as herein described. The lead 610 may be sized and shaped to contact desired tissue and may be adapted to remain in the patient until absorbed. As described herein, lead 610 may comprise electrically conductive materials, such as magnesium, zinc, and more insulative materials such as chitosan, PLLA, PLGA, etc., that connects to a handheld device making impedance measurements intraoperatively and / or postoperatively. In an embodiment, the device 600 may include a break away wire 620 as herein described. The break away wire 620 may be removed from the lead 610 after measurements are taken, leaving the lead 610 in the patient and around the nerve to allow for later measurements when the break away wire 620 may be reconnected to lead 610.

[0070] As described herein, the lead 610 may be used as part of system 1000. In an embodiment, system 1000 may include an external impedance measuring device 1010, for example. It is noted that any of devices 100, 200, 300, 400, 500, 600 may be used as part of the system 1000 where the system 1000 includes the external impedance measuring device 1010. In an embodiment, system 1000 may be handheld. In an embodiment, system 1000 may be handheld may be contained with a surgical field. In an embodiment, system 1000 may include components that are in the surgical field and components that are outside of the surgical field. For example, a display device and electrical stimulation generation system may be outside of the surgical field, while an adapter, which is attached to the electrical stimulation generation system may be positioned within the surgical field. The adapter may be a handheld adapter that is of a similar configuration to any of devices 100, 200, 300, 400, 500, 600. The components inside and outside the surgical field may comprise system 1000 and may communicate with one another through a wired, wireless, or remote connection network as may be desired orsuitable for a particular purpose.

[0071] The following describes aspects applicable to any of the foregoing devices 100, 200,300, 400, 500, 600. It is noted that the handheld device or measurement device as herein described may refer to any or all devices 100, 200, 300, 400, 500, 600 unless context or this disclosure suggests otherwise. Additionally, reference to any one of a device, system, and methods may further include reference to corresponding devices, systems, and methods. For example, a described method may further relate to and include corresponding devices and systems to facilitate the method as described herein. Moreover, a described device may further related to and include corresponding systems and methods that may relate to use of the device as described herein.

[0072] In an embodiment, a method for characterizing soft tissue comprises using a handheld device or system thereof with 2 or more contact electrodes to deliver a voltage such as 1 Vrms at a desired frequency (20Hz to lOOKHz) and with 2 or more electrodes the complex impedance (Z and 9) or conductance (G and icos) is measured. The handheld device may comprise an integrated device or an electrical stimulation device with an adapter (as part of a system) that includes one or more contact electrodes.

[0073] In an embodiment, the method, and corresponding devices and systems, may use a 2- wire measurement where source and sense functionality are provided through the same wires and electrodes. While wire resistance is very small (only a few ohms per hundreds of feet, depending primarily on the gauge (size) of the wire), if the connecting wires are very long, and / or the component to be measured has a very low resistance, the measurement error introduced by wire resistance may be substantial.

[0074] In an embodiment, the method, and corresponding devices and systems, may use a 4- wire measurement where source and sense functions each have a pair of wires, and source and sense may each have their own electrodes. A four-terminal impedance measurement circuit isutilized to measure impedance of a section of tissue. A current-controlled waveform is applied at a particular frequency or set of frequencies via a pair of force connections (current leads), which generate a voltage drop across the tissue to be measured according to Ohm's law V=IR.

[0075] In an embodiment, the measurement devices, systems, and methods may utilize a probe with more than four contacts to make multiple four-wire measurements across multiple sites simultaneously or in sequence allowing the device to establish and actively compare a baseline measurement to a section of tissue in question.

[0076] In an embodiment, a method for assessing tissue may include the use of comparative measurements taken across a range of locations. For example, impedance measurements may be taken on healthy portions of a nerve and over a damaged portion of nerve (which may be adjacent or near one another). In some embodiments, the measurement of two tissue locations may be taken sequentially where the measurement device may present the impedance of the tissue numerically to establish a baseline based on the healthy tissue and to subsequently compare the damaged tissue to these values. Further, in some embodiments, one measurement may be taken before a surgical procedure and one may be take after the surgical procedure, especially during any kind of nerve surgery or a surgery that is going to occur in proximity to a nerve.

[0077] In one embodiment, the user identifies and remembers a baseline for manual comparison. In another embodiment, comparative impedance measurement may use a memory function on the impedance measurement device (or a device that is wirelessly connected or wired, such as a computer, laptop, smart phone, tablet or a dedicated reader device) to maintain the baseline measurement. The device may then provide feedback to the user regarding the relative health of the damaged tissue, especially in the situation in which the tissue is a nerve or a portion thereof. In an embodiment, the memorized baseline measurement on the impedance measurement device may be reset or updated by the user. In an embodiment, the memorizedbaseline measurement on the impedance measurement device may be dynamically or automatically updated by the impedance measurement device. In an embodiment, the impedance measurement device may log or record measured values. In another embodiment, a method for evaluating the impedance of the tissue may include simultaneous measurement of two tissue areas, for example along the length of the nerve.

[0078] The relative impedance of the tissue may be presented using a qualitative indicator such as a color after identification of a baseline, which may be read using a dedicated display device or a wired or wirelessly connected device, such as a laptop, computer, smart phone or tablet. The relative impedance of the tissue may be presented using a directional or locational indicator when two areas are measured simultaneously. Any of the described indicators may be positioned or located on any part of the described devices, including distal ends, arms, faces, bodies, proximal ends, handles, and the like, or may be positioned on another component of the system or outside of but in communication with the system, for example, on a computer or screen in wireless (or wired) communication with the device and / or system.

[0079] A characteristic impedance for each tissue type is identified. This methodology may require the use of correction factors for tissue hydration, tissue diameter, or other characteristics that vary in a surgical environment. In this situation, the system may utilize artificial intelligence or machine learning to apply the appropriate correction factors. In addition or alternatively, independent sensors may be utilized to determine certain characteristics present in a surgical environment or field. For example, an electronic caliper that is wirelessly connected to the system may determine a tissue diameter. This information can be relayed or otherwise communicated to the system. Then this information can be utilized to create or incorporate a correction factor.

[0080] In an embodiment, the measurement method may use additional measurements of tissue such as hydration, tissue diameter, etc., to normalize or apply a correction factor to improvemeasurement accuracy and to help isolate tissue impedance or the system may include sensor that will automatically make these measurements without the need for human intervention. The information can be utilized by the system to either determine an appropriate correction factor or can be used to determine an already known correction factor and apply such.

[0081] Noise reduction techniques may be utilized in any combination of the following to improve precision and accuracy of the measurement:• Impedance measurement circuit may utilize low noise instrumentation amplifier• Four-Terminal measurement techniques• EMI shielding to improve measurements• Probe design may be implemented to minimize the distance between measurement and impedance measurement circuity

[0082] The methods above, and devices and systems thereof, for assessing the health of nerve tissue may utilize impedance or conductance measurements to distinguish between tissue types and between damaged tissue and healthy tissue. For example the methods, devices and system may be utilized to determine between healthy nerves and damaged nerves. It may also be used to determine the relative health of a nerve. Thus, the impedance measuring device of the present disclosure includes a circuit with the capability of measuring, storing, comparing, logging, assessing, processing, and relaying information about impedance measurements taken through the device’s contacts / electrodes. In an embodiment the impedance measuring device may also include capabilities such as the electrical stimulation device disclosed in U.S. Patent No. 10,470,678 or provide nerve regeneration therapy as disclosed in U.S. Patent Nos. 11,872,401 and 11,766,567, which are each incorporated herein by reference in their entirety. In an embodiment, the impedance measuring device may be a standalone, handheld device with a plurality of electrical contacts.

[0083] As described herein, in an embodiment, the impedance measuring device may be part of an impedance measurement system and may include an impedance measuring device, electrode contacts, and leads.

[0084] In at least one embodiment of the device, it may be desirable to equip the patient contacting portion with at least 2 contacts. In an embodiment those contacts may include a pair of current sourcing contacts and a pair of voltage sensing contacts such that 4 contacts are used. As an example, in this embodiment the voltage sensing contacts are placed between the current sourcing contacts as shown in FIG. 10. It is noted that these configurations of contacts / electrodes may be applied to any or all devices 100, 200, 300, 400, 500, 600.

[0085] In another embodiment, a single pair of contacts may serve as both the current sourcing and sensing contacts, but use a 4-wire cable, analogous to “Kelvin Clips” such that only 2 electrode contacts are used to interface with the tissue.

[0086] In an embodiment, the system may use a plurality of contacts where impedance is measured between a series of contact pairs (by delivering current and measuring voltage across various contact) pairs to assess current along an axis or across a range of areas on the tissue under test. The use of multiple leads can speed placement and use intraoperatively by reducing the need for precise placement over the injury site or enable more precise identification of the zone of injury by testing across different contact pairs. The multiple contacts can also be used to track changes along the length of the nerve, which could indicate injury or disease progression or recovery or regeneration of injured axons.

[0087] In an embodiment the electrical contacts may be stainless steel, platinum, platinum: iridium, etc. In an embodiment the electrical contacts may be coated in gold. In an embodiment, the one or more electrode contacts may be any combination of biocompatible conductors.

[0088] As described herein, in one embodiment a tweezer shaped probe with an integrated cuff may be used to isolate a nerve and take a measurement, such as an impedance measurement, see FIGs. 1-2 and devices 100, 200, 300, for example. It is contemplated that different probe heads may be utilized for different nerve sizes. In this apparatus, a plurality of contacts, with current sourcing or voltage sensing functionality are positioned in the center of the cuff. In anapparatus that constrains the nerve, it may desirable to include a slot or window between the electrical contacts to allow for visualization of the tissue being measured for improved placement or adjustment. As described herein, the tweezers apparatus may be implemented with a resting closed feature such that a nerve and tweezer can be held in place during a measurement, see FIG. 1 and device 100, for example.

[0089] As described herein, a tweezer or probe design may be provided that includes a dip, curve, or non-uniform profile in the electrical contacts to accommodate and improve contact with a nerve or other tissue, see FIG. 2 and devices 200 and 300, for example, including curved shapes. It is noted that other shapes are also herein contemplated, including concave or convex shapes, ribbed shapes, shapes with protrusions or recesses, other patterning, and the like. This embodiment may also be designed with a low closure force enabling a loose grip that maintains contact while still allowing the probe to be slid along the nerve. A low closure force allows the probe to move along the nerve without damaging the tissue to facilitate measurement along the length of the nerve to find the injury. It is noted that such low closure force may be applied to any of the described embodiments herein, including devices 100, 200, 300, 500, etc.

[0090] In another embodiment, a multi-contact probe with electrode contacts protruding from the contact header may be utilized to ensure good connection to tissue. An example of an embodiment would be spring loaded pogo pin type electrodes in a contact header at the end of a handle / handheld device, see FIG. 4, for example.

[0091] In an embodiment the multi-contact probe apparatus may include the impedance measurement and processing circuity within the same housing. In another embodiment, the impedance measurement and processing circuitry may be in a separate device that is wirelessly connected or wired with the multi -contact probe apparatus.

[0092] In an embodiment, flexible or retractable contacts may allow the device to ensure contact between the flexible tissue and all of the multiple contacts simultaneously.

[0093] In an embodiment the multi-contact probe apparatus may connect, physically or remotely, to an external impedance measuring device to process the electrical impedance data.

[0094] In another embodiment, impedance measurement may be performed using a multicontact lead with a soft spiral header design with a retaining feature that ensures good contact with the tissue, see FIGs. 5-8 and device 500, for example. An example of an embodiment would be a flex circuit type lead that connects to a handheld device making impedance measurements.

[0095] An example of an embodiment may include a grip feature to facilitate opening the spiral of the lead to place the lead around the tissue.

[0096] In an embodiment, the flex circuit’s electrode contacts may be raised or textured to provide better contact with the tissue under measurement.

[0097] In another embodiment, an implantable multi-contact bioabsorbable lead with bioabsorbable contacts may be utilized to allow measurement see FIG. 9 and device 600, for example. It is noted that device 600 may have a similar distal tip to device 500 including any or all of a gripping protrusion, retaining protrusion, and / or interior retaining wall. In an embodiment, device 600 may comprise a spiral header. An implantable multi-contact bioabsorbable lead with a soft design that ensures good contact with the tissue while enabling post-operative measurement.

[0098] An example of an embodiment would be a bioabsorbable lead, including the electrode contacts, using electrically conductive materials, such as Magnesium, Zinc, and more insulative materials such as Chitosan, PLLA, PLGA, etc., that connects to a handheld device making impedance measurements intraoperatively and / or postoperatively.

[0099] In an embodiment the breakaway wire portion may then be removed, leaving the electrode body around the nerve to allow for continued measurements to monitor tissue over longer periods of time. In an embodiment the bioabsorbable lead may include the ability toremotely communicate with an external impedance measuring device.

[0100] In an embodiment, the measurement system may utilize a probe with more than four contacts to make multiple four-wire measurements across multiple sites simultaneously or in sequence allows the device to establish and actively compare a baseline measurement to a section of tissue in question.

[0101] The above-described embodiments may comprise an integrated device or may be an adapter attached to a separate electrical stimulation device such as that disclosed in U.S. Patent No. 10,470,678, which is incorporated herein by reference in its entirety.

[0102] The handheld device reads impedance measurements between two or more sense contacts through a unique multi-electrode interface and provides that information back to the user. The device may compare or manipulate both the imaginary and real components of the complex impedance measurements.Z = R + iXZ is the complex impedance, R is the real resistance, i is the imaginary unit, and X is the reactance.

[0103] In embodiments designed to make multiple measurements; it may be desirable for the device to implement functionality to aid in comparison. This functionality may include an input control for designating a measurement as the baseline or as the comparative measurement.

[0104] Using the complex impedance measurements, or another proxy thereof, the device may relay this information to a health care professional to help determine relative health of the nerve tissue being measured.

[0105] Using the complex impedance measurements, or another proxy thereof, the device may relay the characteristic impedance of the tissue to a health care professional to help distinguish various tissues such as nerve, muscle, tendon, connective tissue etc.

[0106] In some embodiments tissue characteristic information may be displayed directly on the device. This display may be via simple digital segmented liquid crystal display, or a more higher resolution pixelated screen.

[0107] In other embodiments tissue characteristic information may be displayed separately, for example on a tablet or other larger display.

[0108] In some embodiments tissue characteristic information may be strictly numeric.

[0109] In other embodiments, the information may be presented as relative change to a baseline using for example color, light intensity, audible pitch.

[0110] Although the embodiments of the present invention have been illustrated in the accompanying drawings and described in the foregoing detailed description, it is to be understood that the present disclosure is not to be limited to just the embodiments disclosed, but that the disclosure described herein is capable of numerous rearrangements, modifications and substitutions without departing from the scope of the claims hereafter. The terms “includes,” “including,” and “include” are inclusive and have the same scope as “comprises,” “comprising,” and “comprise” respectively. The claims as follows are intended to include all modifications and alterations insofar as they come within the scope of the claims or the equivalent thereof.

Claims

CLAIMSWhat is claimed is:

1. A method comprising: measuring complex impedance present in tissue; characterizing health of the tissue from the measuring of complex impedance.

2. The method of claim 1, further comprising a second measuring of complex impedance present in the tissue wherein the second measuring of complex impedance is presented as a relative number compared to the measuring of complex impedance.

3. The method of claim 2 wherein a device presents the second measuring complex impedance as a qualitative indication of complex impedance relative to the measuring complex impedance.

4. A method comprising: measuring complex impedance present in tissue; characterizing of the tissue based on the measuring of complex impedance.

5. A method comprising: measuring complex impedance present in tissue; characterizing a type of tissue of the tissue from the measuring of complex impedance.

6. A probe for conducting Kelvin style complex impedance measurements on a nerve, wherein the probe comprises an arm that circumferentially insulates and constrains the nerve.

7. The probe of claim 6 further comprising a window or slot to visualize the nerve.

8. The probe of claim 6 further comprising a second arm, wherein the arm and the second arm are biased to a closed position to minimize risk to the nerve during movement along a length of the nerve.

9. The probe of claim 6 further comprising a pair of individual contacts on the arm that are spring loaded.

10. The probe of claim 6 further comprising at least one contact printed on a flexible substrate of an arum.

11. The probe of claim 6 further comprising a plurality of contacts used to assess impedance at multiple points on the nerve.

12. The probe of claim 11, wherein the plurality of contacts are multiplexed or switched between sourcing and sensing measurement to allow a 4-wire impedance measurement at multiple points on the nerve.

13. An implantable electrode comprising: an electrode body; one or more lead connections; and a plurality of contacts for conducting a Kelvin style complex impedance measurement on a nerve.

14. The implantable electrode of claim 13, wherein the plurality of contacts and the electrode body are bioabsorbable and the lead connections are retractable percutaneously through skin.

15. A nerve measurement system, comprising: a probe with two or more contacts each allocated to a sourcing or sensing functionality; control circuitry generating an excitation signal via designated source electrodes; measurement circuitry connected to a set of sensing electrodes; data storage; an input control for identifying a baseline measurement; and an indication output for indicating relative measurement.

16. The system of claim 15, wherein the indication output is via a built in display.

17. The system of claim 15, wherein the indication output is via a remote display.

18. The system of claim 15, wherein the indication output is via a generation of an audio tone.

19. The system of claim 15, wherein the sourcing and sensing electrodes are the same.

20. The system of claim 15, wherein the sourcing and sensing electrodes are two distinct pairs.

21. The system of claim 15, wherein the sourcing and sensing electrodes are multiplexed across three or more electrodes spaced along an axial length of a nerve probe.

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