WO2017072768A2

WO2017072768A2 - Systems and methods for locating and optionally treating nerve fibers

Info

Publication number: WO2017072768A2
Application number: PCT/IL2016/051160
Authority: WO
Inventors: Ilan KRYMKA; Assaf Dekel; Dan Rappaport
Original assignee: Tpm Medical Systems Ltd.
Priority date: 2015-10-28
Filing date: 2016-10-27
Publication date: 2017-05-04
Also published as: WO2017072768A3

Abstract

A device for locating nerve fibers in a tissue is provided. The device includes a probe having a distal tip which includes at least one capacitance sensor and a processing unit for collecting data from the at least one capacitive sensor and determining displacement of nerve fibers with respect to the distal tip based on said data. The present invention also encompasses a system for locating and treating nerve fibers.

Description

SYSTEMS AND METHODS FOR LOCATING AND OPTIONALLY TREATING

NERVE FIBERS

FIELD AND BACKGROUND OF THE INVENTION

The present invention relates to a system for locating nerve fibers within a tissue and, more particularly, to a system for locating and ablating nerve fibers such as nociceptive afferents in a body region such as a joint.

Sensory neuronal activity, specifically via nociceptive afferents, is the nervous system's response to certain harmful or potentially harmful stimuli. Nociception triggers a variety of physiological and behavioral responses and usually results in a subjective experience of pain. The most common sources of pain stem from headaches, pain from injury, backaches and joint pain.

Osteoarthritis is the most common cause of joint pain. Osteoarthritis is a degenerative disorder arising from the biochemical breakdown of articular (hyaline) cartilage in the synovial joints. Osteoarthritis affects not only the articular cartilage but also the entire joint organ, including the subchondral bone and synovium. Osteoarthritis predominantly affects the weight-bearing joints, including the knees, hips, cervical and lumbosacral spine, and feet. Other commonly affected joints include the distal interphalangeal (DIP), proximal interphalangeal (PIP), and carpometacarpal (CMC) joints.

Historically, osteoarthritis has been divided into primary and secondary forms, though this division is somewhat artificial. Secondary osteoarthritis is conceptually easier to understand: it refers to disease of the synovial joints that results from some predisposing condition that has adversely altered the joint tissues (e.g., trauma to articular cartilage or subchondral bone). Secondary osteoarthritis can occur in relatively young individuals.

The definition of primary osteoarthritis is more nebulous. Although this form of osteoarthritis is related to the aging process and typically occurs in older individuals, it is, in the broadest sense of the term, an idiopathic phenomenon, occurring in previously intact joints and having no apparent initiating factor.

At present, there is no effective cure for osteoarthritis. However, treatments can help to reduce osteoarthritic pain and maintain joint movement. Osteoarthritis symptoms can be relieved by a variety of medications including oral analgesics and non-steroidal anti-inflammatory agents (NSAIDS) and intraarticular injections of corticosteroids or lubricants such as hyaluronic acid derivatives (Hyalgan, Synvisc).

In more severe cases, bones can be realigned via osteotomy which can shift body weight away from the worn-out part of the knee, or the joint can be replaced via arthroplasty.

Although such treatments can reduce pain associated with osteoarthritis and restore/maintain some joint movement, according to the arthritis foundation two-thirds of people with arthritis have tried alternative therapies.

Thus, there remains a need for an approach that can be used to locate nerve fibers in a tissue and optionally ablate such fibers in order to relieve pain.

SUMMARY OF THE INVENTION

According to one aspect of the present invention there is provided a device for locating nerve fibers in a tissue comprising: (a) a probe including a distal tip having at least one capacitance sensor; and (b) a processing unit for: (i) collecting data from the at least one capacitive sensor; and (ii) determining displacement of nerve fibers with respect to the distal tip based on the data.

According to further features in preferred embodiments of the invention described below, the distal tip is covered with insulative material.

According to still further features in the described preferred embodiments the at least one capacitance sensor includes an array of capacitance sensors.

According to still further features in the described preferred embodiments the processing unit is also configured for determining a type of nerve fibers based on the data.

According to still further features in the described preferred embodiments the device further comprising a user interface for providing feedback relating to a proximity of the nerve fibers to the distal tip.

According to still further features in the described preferred embodiments is effected by comparing the data to known values. According to still further features in the described preferred embodiments the data is derived from a capacitance waveform.

According to still further features in the described preferred embodiments the data includes resonance or impedance data.

According to still further features in the described preferred embodiments the distal tip is configured for intra- articular use.

According to still further features in the described preferred embodiments the device further comprising at least one electrode for electrically stimulating tissue.

According to still further features in the described preferred embodiments the array includes at least two capacitance sensors having directional capacitance sensing capabilities.

According to still further features in the described preferred embodiments n each of the at least two capacitance sensors has a different directional capacitance sensing.

According to still further features in the described preferred embodiments each of the capacitance sensors is shaped as a rectangle, square or circle.

According to still further features in the described preferred embodiments each of the capacitance sensors includes a conducting element coated with a dielectric layer.

According to still further features in the described preferred embodiments the conducting element is composed of at least one metal selected from the group consisting of stainless steel, iron, aluminum, and copper.

According to still further features in the described preferred embodiments the at least one capacitance sensor is 0.5-5 mm thick and 25-250 mm in length.

According to still further features in the described preferred embodiments the capacitance waveform is a digital waveform.

According to another aspect of the present invention there is provided a system comprising the device for locating nerve fibers and a probe for disrupting conductance in the nerve fibers.

According to still further features in the described preferred embodiments the device and the probe are enclosed in a single housing.

According to still further features in the described preferred embodiments n the probe is a cryoablation probe, a chemical ablation probe, an RF probe or a thermal ablation probe. According to still further features in the described preferred embodiments the probe includes a guide for guiding an attachable tissue treatment probe.

According to yet another aspect of the present invention there is provided system for treating neuropathic pain comprising: (a) a device for locating nerve fibers in a tissue; and (b) a probe capable of disrupting conductance in the nerve fibers.

According to still further features in the described preferred embodiments the device is configured for intra articular use.

According to still further features in the described preferred embodiments the nerve fibers are nociceptive afferents.

According to still further features in the described preferred embodiments the probe is a cryoablation probe, a chemical ablation probe, an RF probe or a thermal ablation probe.

According to still further features in the described preferred embodiments the device is configured for determining capacitance of tissue.

According to still further features in the described preferred embodiments the device is configured for determining an electrical field, electroresonance, impedance or capacitance of intra articular tissue.

According to still further features in the described preferred embodiments the system further comprising a processing unit for controlling operation of the probe within the tissue space based on the mapping of the nerve fibers.

According to still further features in the described preferred embodiments the system further comprising a processing unit for providing feedback on quality of disrupting conductance in the nerve fibers.

According to an additional aspect of the present invention there is provided method of treating neuropathic pain comprising: (a) electrically stimulating a tissue; (b) using a capacitance sensor to measure capacitance changes resulting from the electrical stimulation thereby locating nerve fibers in a tissue; and (c) disrupting conductance of the nerve fibers.

According to still further features in the described preferred embodiments the method further comprising assessing conductance of the nerve fibers following (c). The present invention successfully addresses the shortcomings of the presently known configurations by providing a device for mapping nerve fibers in a tissue and a system for using same to map and treat nerve fibers.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, suitable methods and materials are described below. In case of conflict, the patent specification, including definitions, will control. In addition, the materials, methods, and examples are illustrative only and not intended to be limiting.

Implementation of the method and system of the present invention involves performing or completing selected tasks or steps manually, automatically, or a combination thereof. Moreover, according to actual instrumentation and equipment of preferred embodiments of the method and system of the present invention, several selected steps could be implemented by hardware or by software on any operating system of any firmware or a combination thereof. For example, as hardware, selected steps of the invention could be implemented as a chip or a circuit. As software, selected steps of the invention could be implemented as a plurality of software instructions being executed by a computer using any suitable operating system. In any case, selected steps of the method and system of the invention could be described as being performed by a data processor, such as a computing platform for executing a plurality of instructions.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

The invention is herein described, by way of example only, with reference to the accompanying drawings. With specific reference now to the drawings in detail, it is stressed that the particulars shown are by way of example and for purposes of illustrative discussion of the preferred embodiments of the present invention only, and are presented in the cause of providing what is believed to be the most useful and readily understood description of the principles and conceptual aspects of the invention. In this regard, no attempt is made to show structural details of the invention in more detail than is necessary for a fundamental understanding of the invention, the description taken with the drawings making apparent to those skilled in the art how the several forms of the invention may be embodied in practice.

In the drawings:

FIG. 1 illustrates one embodiment of the present device.

FIG. 2 illustrates a capacitance sensor utilizable by the present device.

FIG. 3 is a box diagram of the various functional components of the control unit of the present device.

FIGs. 4A-B illustrate the mapping probe of the present device (Figure 4 A) and the sensor array tip thereof (Figure 4B).

FIGs. 4C-E illustrate the present probe (Figure 4C), a nerve severing needle (Figure 4D) and the probe fitted with the needle (Figure 4E).

FIG. 5 is a flow chart outlining the steps of acquiring and processing capacitance data according to the teachings of the present invention.

FIG. 6A is an image showing the experimental setup.

FIGs. 6B-C are graphs of capacitance data acquired from the experimental setup of Figure 6 A.

FIG. 7 is a flow chart outlining the steps of outputting nerve location and type to a user.

FIGs. 8-9 illustrate a mapping probe having a guide for mounting an ablation probe (Figure 8) and a mapping probe and an ablation probe enclosed within a single housing (Figure 9).

FIG. 10 is an anatomical illustration of a the knee joint and associated tissue structures.

FIG. 11 illustrates a knee procedure using the present system.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention is of a system which can be used to locate nerve fibers within a tissue. Specifically, the present invention can be used to accurately locate nerve fibers such as nociceptive afferents and optionally guide a treatment device such as an ablation probe to the nerve fiber.

The principles and operation of the present invention may be better understood with reference to the drawings and accompanying descriptions. Before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details set forth in the following description or exemplified by the Examples. The invention is capable of other embodiments or of being practiced or carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein is for the purpose of description and should not be regarded as limiting.

Detection of neuronal activity can be carried out via Nerve conduction (NC) studies which utilize electrodes for measuring electrical signals from the skin. Although NC can be used to obtain a measure of neuronal activity it is incapable of precisely locating a nerve fiber in the tissue due to a low signal-to-noise ratio and signal attenuation.

Approaches for more accurately locating a tissue type of interest such as nerve tissue are also known in the art. For example, US20120323134 discloses a probe having electrodes for applying a waveform signal to tissue and measuring the electrical characteristics (e.g., impedance) of the signal transmitted through the tissue.

While approaches for directly measuring electrical signals transmitted through tissue can be effective in mapping nerve fibers, such approaches can produce inaccurate results since some nerve fibers are insulated by a myelin sheath and/or layers of fat tissue.

While reducing the present invention to practice, the present inventors devised a probe which can be used to locate a nerve fiber in tissue without directly measuring an electrical signal transmitted through the tissue.

As is further described herein under, the present probe utilizes one or more capacitance sensors to indirectly detect a change in electrical activity resulting from electrical stimulation of a tissue region.

As is shown in the Examples section, such an approach can be used to locate and map nerve fibers in any tissue region with an accuracy of +/- 2 millimeters.

Thus, according to one aspect of the present invention there is provided a device for locating nerve fibers in a tissue.

As used herein, the term "locating" and the phrase "determining displacement" refer to obtaining actual or relative location of a nerve fiber with respect to a probe tip. Actual location can be a distance in units such as micrometers, millimeters etc. on one or more axis, or a spatial location (X and Y or X, Y and Z coordinates) with respect to the probe tip. Relative location is a measure of decreasing or increasing distance to the probe tip when the latter is moved with respect to the tissue probed.

The device of the present invention includes a probe having a distal tip with at least one capacitance sensor. The number of capacitance sensors mounted on the probe tip determine the type of location data obtained. For example, a single capacitance sensor can be used to obtain actual or relative location along one axis, while three or more capacitance sensors can be used to map the spatial location of a nerve fiber in a tissue.

As is further described hereunder, the present probe can include an array of capacitance sensors (e.g. 3, 4, 5, 6, 7, 8, 9, 10 or more) having directional capacitance- sensing capabilities. Each capacitance sensor can be mounted in the same direction or angled at a unique direction, e.g., the sensing plane of the array can form a flat (same sensing direction) or shaped (different sensing directions) surface. The capacitance sensor can be rectangular, square or round in shape with a thickness of 0.5-5 mm a sensing length (along longest axis) of 250-2000 μιη and a sensing area of 100 2 -40002 μιη. The capacitance sensor can be fabricated from a conducting element composed of stainless steel, iron, aluminum, and/or copper coated with a dielectric layer such as Teflon.

The capacitance sensor and an array including same are further described herein below with reference to the accompanying Figures.

The device of the present invention also includes a processing unit for collecting data from at least one capacitive sensor and determining, based on these data, displacement (actual or relative location) of nerve fibers with respect to the distal tip of the probe. The data can be collected as an analog signal and converted to digital data by the processing unit. The processing unit is also configured for determining a type of nerve fibers based on these data.

The processing unit forms a part of a control unit which provides power, user interface functions (for settings and feedback), signals to and from the probe and to a stimulation electrode (described below) and communication capabilities.

The processing unit can be a computing platform running dedicated software configured for performing the above functions. Such a platform can be, for example, Platform based on TI (Texas Instrument) Chipset, Including FDC22xx, 28bit Capacitance to Digital converter and MSP430 Microcontroller. The FDC device can convert the analog signal to digital signal; the Microcontroller controls the human interface and data acquisition.

The data obtained can be derived from a capacitance waveform and/or it can include resonance or impedance data. Such data can be compared to known values for determining a location or it can be used to identify a peak signal which can be used to determine a relative location by moving the probe tip in the tissue.

The functions of the processing unit of the present device are further described hereinbelow with reference to the accompanying Figures.

The probe can be of any dimensions suitable for probing tissue. A typical probe useful in probing an intrabody region such as a lumen, a tissue or a space (e.g. intraarticular space) can be configured as an elongated body having a length of 20-500 mm and a diameter/width of 1-5 mm. The elongated body can terminate with a tapered probe tip 1-10 mm in length and 1-5 mm in diameter with the sensor array mounted on a surface of the elongated body (preferably at the tip). The probe can be fabricated form a metal, an alloy a ceramic or a polymer using well known approaches. It can be fabricated from, or coated with a biocompatible material and/or provided with a sterile biocompatible sheath for re-use or configured for sterilization. The capacitance sensor array can be removable from the probe tip and be reusable or replaceable. Several types of array can be used with the probe depending on types of tissues probed and types of nerve fibers identified.

The present device can include a mechanism for automatically identifying the array fitted to the probe tip and changing the processing parameters accordingly.

The present device also includes one or more electrodes for stimulating the tissue region probed. The electrode(s) are configured for attachment at an external surface of the tissue region (e.g. skin) and provide an electrical signal (originating from the control unit) to the tissue. This electrical signal is specifically tuned for exciting nerve fiber polarization which is detectable by the capacitance sensors of the probe.

Referring now to the drawings, Figure 1 illustrates one embodiment of the present device which is referred to herein as device 10. Device 10 includes a processing and display unit 12 and a probe 14 (shown separately in Figures 4A-B). Probe 14 can be wired (16) to unit 12 or it can communicate therewith via wireless communication (16). In the latter configuration, power to probe 14 can be provided by an onboard battery or via a wired connection to a separate power source.

Unit 12 includes a nerve stimulator 18 for electrically stimulating tissue. Simulator 18 provides an electrical signal of Current/voltage source 1-20 rectangular pulses 0.1 - 16 millisecond pulse width, 0.1 - 1000 millisecond between pulses, 0.1 - 16 Milliamp amplitude, or coded interval between pulses to a tissue (e.g. skin) through an electrode 20. Electrode 20 can be configured as a tissue contact electrode shaped as a flat disc, a needle or the like. The stimulation signal provided by simulator 18 depolarizes a nerve fiber 19 in the region, this results in tissue capacitance (caused by nerve fiber depolarization) which is detectable by probe 14. Probe 14 includes capacitance sensors 22 (three shown) mounted on elongated body 24 at or near tip 26. Capacitance sensors 22 can be arranged around elongated body 24 (with each sensor covering a 120 degree sector).

A capacitance signal generated by each sensor 22 is collected by a data acquisition component 27 of probe 14 and the collected signals are relayed (via connection 16) to a capacitor to digital unit 28 of processing and display unit 12 for analog to digital conversion.

The resultant digital signals are then processed by data processing and control unit 30 and the processed data is displayed on user interface 32 as actual or relative location of a nerve fiber 19 with respect to a probe tip 26. Figure 5 provide a flow chart outlining the steps of capacitance signal acquisition and processing. The Examples section which follows provides a more detailed description of how a capacitance signal can be processed to provide displacement between probe tip and nerve fiber.

FIG. 2 illustrates capacitance sensor 22 utilizable by probe 14 of device 10. Capacitance sensor 22 includes a metallic sensing plate 40 (Copper) surrounded with a thick layer of insulative material 42 (Polyimide) provided on top of a base plate 44 (FR- 4). A lead 46 (Copper) runs through base plate 42 and connects sensing plate 40 to data acquisition component 27 of probe 14. An optional ground plate 48 (Polyimide) is positioned below base plate 44.

The capacitance sensor of the present invention along with related circuitry forms an RLC circuit capable of measuring an RLC response resulting from Nerve depolarization. Electrical resonance occurs in an electric circuit at a particular resonance frequency when the imaginary parts of impedances or admittances of circuit elements cancel each other. In some circuits this happens when the impedance between the input and output of the circuit is almost zero and the transfer function is close to one. An RLC circuit is an electrical circuit consisting of a resistor (R), an inductor (L), and a capacitor (C), connected in series or in parallel. The circuit forms a harmonic oscillator for current and resonates similarly to an LC circuit. The three circuit elements can be combined in a number of different topologies. All three elements in series or all three elements in parallel are the simplest in concept and the most straightforward to analyze. A resonance sensor detects the depolarization stage of a nerve action potential running through a nerve. Nerve depolarization is characterized by changes in gates surface potential and resistance, i.e. changes in RLC response.

FIG. 3 is a box diagram of the various functional components of control unit 12 of device 10. Capacitance sensors 22 of probe 14 communicate an analog signal to capacitive to digital unit 28 which converts the analog information to digital information. Data processing module 31 of processing unit 30 processes the digital information and CPU unit 33 provides nerve location data to LCD display 37 of interface 32. CPU 33 controls all system function and timing. Keyboard 39 enables a user to input parameters and other functions which can be saved in memory 35.

FIGs. 4A-B illustrate a probe 14 with a three capacitance sensors 22 each configured for covering a 120° degree sector.

FIGs. 4C-E illustrate probe 14 and a needle 15 which can be fitted over elongated body 26 of probe 14. Needle 15 can be used for severing a nerve fiber located by capacitance sensors 22 of probe 14. Probe 14 and needle 15 are further described hereinbelow in context with system 100.

FIG. 5 is a flow chart outlining the steps of acquiring and processing capacitance data. Step A - position an sensor array proximal to anatomical landmark of the required nerve fiber and stimulate the nerve;

Step B - measure the sensor signal and convert each sensor in the array to digital signal;

Step C - combine information from all sensor to calculate relative position and nerve type;

Step D - calculate nerve location relative to nerve; and

Step E - compare data to data base and define nerve type accordingly.

Step A - receive data indicative of nerve fiber displacement with respect to probe tip;

Step B - display direction of nerve fiber with respect to probe tip;

Step C - display depth of nerve fiber with respect to probe tip;

Step D - display distance of nerve fiber with respect to probe tip; and

Step E - display a type of nerve fiber.

Device 10 can be used along with additional sensors (e.g. the capacitance sensors described herein) for facilitating nerve fiber localization. Such external sensors (not a part of the probe of device 10) can be attached directly to the tissue (e.g. skin) and serve to provide a reference signal for the sensors of device 10. For example, by positioning several capacitance sensors around a tissue site and acquiring several signals (following electrical stimulation of the tissue as describe above), a general region of a nerve fiber can be identified. Device 10 can then be used to probe this region thereby facilitating nerve fiber identification.

Device 10 can also be used in conjunction with a tissue treatment device in order to locate and treat a specific nerve fiber. Such treatment can be used to repair damaged nerves and/or restore/enhance nerve function. Alternatively, treatment can be used to diminish or abolish nerve function. The latter can be effected via thermal, cryogenic, radiofrequency (RF), laser or chemical denervation (e.g. ablation) or via mechanical denervation. The treatment device can be used separately from device 10 or it can be operatively combined therewith via a guide mounted on probe 14. One use for such a combined localization and treatment system is in the management of pain, specifically joint-related pain. Joint-related pain (e.g. caused by osteoarthritis) is typically treated via medications or surgery. Alternative approaches for treating joint-related pain have been proposed and include direct disruption of afferent signaling via chemical or mechanical denervation.

For example, WO2004080384 describes a method of denervating or blocking nerve signaling from an axon of the intramedullary canal of a subchondral bone. Denervation is effected by accessing the intramedullary canal and severing endings of at least one axon near the epiphysis (i.e., bone end) using a surgical tool (e.g., scissors, a scalpel, clips, suction aspirator). Although such an approach can be effective in disrupting pain signaling from a joint, it requires surgical access to the intramedullary canal of a bone and carries a risk of osteomyelitis.

The present system combines device 10 for mapping nociceptive afferents of a joint with a probe for chemically or physically ablating mapped nociceptive afferents (also referred to herein as ablation probe). The nociceptive afferents can be intraarticular (in the capsule or other soft tissue or in the bone e.g. intramedullary afferents within the femur, tibia or fibula bones in the case of a knee joint).

Device 10 can be integrated with the ablation probe within a single housing, in which case, the capacitance sensor array can be arranged around, or disposed side by side to, the ablation probe. Alternatively, a guide can be used to attach device 10 to the ablation probe and align the sensor array with the working tip of the ablation probe. Still alternatively, device 10 and the ablation probe can be provided as separately maneuverable instruments. In any case, device 10 and ablation probe can be connected to a central unit for processing sensor signals from device 10 and operating the ablation probe accordingly. The operation of the ablation probe can be controlled by the user or by the control unit according to location data provided by device 10. In the former embodiment, device 10 can be used to map afferents in the joint space and display their position as a spatial 3D image. The tip of ablation probe can be provided with a position marker (optical or electrical) such that the spatial location of ablation probe is displayed to the user within the spatial 3D image thus providing a positional relationship between probe tip and afferents. The user can then selectively ablate afferents using ablation probe. In the latter embodiment, the control unit automatically actuates ablation probe according to mapped data with the user simply maneuvering ablation probe within the joint space. In such an embodiment, the control unit automatically actuates ablation signal (and selects appropriate duty cycle) whenever the ablation probe is adjacent to a nociceptive afferent.

Figures 8-9 illustrate one embodiment of a system which includes nerve fiber location and ablation functions.

This system - referred to herein as system 100, includes probe 12 and a guide 102 or a probe 12 co-housed with a denervation device 104 within a single enclosure 106.

Several types of denervation devices 104 can be used by system 100 An RF probe suitable for use with system 100 can include an RF needle (e.g. Kimberly-Clark Cooled Radiofrequency System) that is capable of delivering a monopolar or bipolar RF signal having a frequency of 300-3,000 kHz and a 5-50% duty cycle. Such a signal can selectively ablate neuronal tissue embedded within soft or hard tissues of the joint.

System 100 can also utilize a cryoprobe such as the D.O.R.C. CryoStar or the Frigitronics Cryo-Plus. The extent and duration of tissue cooling can be selected according to the tissue and effect desired. In the case of system 100, a cryoprobe can cool the tissue to about -40° C for about 1-10 seconds in order to selectively ablate neuronal tissue and minimize damage to surrounding hard or soft tissues. Cryo-Ablation can be performed using 2-5 short cycles of cooling and active thawing for optimal performance.

System 100 can also utilize a thermal ablation probe which utilizes HIFU (Hi Intensity Focused Ultrasound), Microwave, Laser or heated fluid for ablation. The extent and duration of tissue heating can be selected according to the tissue and effect desired. In the case of system 100, a thermal probe can heat the tissue to about 40-100° C for 1-10 seconds in order to selectively ablate neuronal tissue and minimize damage to surrounding hard or soft tissues.

Chemical ablation of a nociceptive afferent can be effected by using a needle (e.g. 18-24 Gauge needle)) to deliver a chemical such as Botulinum Toxin. Chemical ablation can be accompanied by injection of alcohol, a steroid, an anti-rheumatic or the like.

Figures 4C-E illustrate yet another embodiment of system 100 in which probe 14 carries a physical denervation device 104 (needle 15) around elongated body 24 of probe 14. Once a nerve fiber is located by probe 14, needle 15 can be advanced forward over elongated body 24 to sever a nerve fiber located at tip 26 of probe 14.

The present system can be used to treat any painful joint including an osteoarthritis hip, an ankle, a shoulder, a spine facet joint and the like. The present system is particularly suitable for use in the knee joint as is illustrated in the following example.

In a routine arthroscopic setting, utilizing lavage (fluids) or a dry procedure the knee will be examined using a regular scope (camera) introduced through an access port. Anatomical structures such as the meniscus, cruciate ligaments, synovial tissue, cartilage, joint capsule etc. (Figure 10) are identified and mapped. The procedure can also be monitored using ultrasound fluoroscopic or CT guidance or another imaging modality such as magnetic resonance imaging. The mapping sensor is then introduced into the knee through a dedicated port and actuated to map points of nerve endings via capacitance, electroresonance, nerve conduction tests, electrical field detection or optical reflection. The ablation probe introduced with the mapping probe or independently is then activated to automatically or manually ablate nerve endings or nerve stimulation points (Figure 11).

Although device 10 is preferred for mapping nociceptive afferents it will be appreciated that system 100 can alternatively utilize electrical or optical sensors for nerve fiber localization.

Electrical sensors can be configured to detect electroresonance, tissue impedance, nerve conduction or an electrical field. For example, electrical sensors can be configured to detect nerve signal amplitudes that are in the microvolt (μ\ range (range of sensory neurons). Since the signal amplitude for motor neurons are orders of magnitude higher, such detection can distinguish sensory neurons from motor neurons and from non-neuronal tissue. Electrical sensors can also a tissue characterization array such as that described in US20130267821.

Optical sensors can include optic fibers with magnification capabilities in the range of 200-300X for visualizing nerve fibers in the tissue.

As used herein the term "about" refers to ± 10 %. Additional objects, advantages, and novel features of the present invention will become apparent to one ordinarily skilled in the art upon examination of the following examples, which are not intended to be limiting. EXAMPLES

Reference is now made to the following example, which together with the above descriptions, illustrate the invention in a non limiting fashion.

Locating a nerve fiber in goat tissue

Materials and Methods

The experimental setup is shown in Figure 6A. A stimulation electrode was positioned percutaneously next to goat tibial and peroneal nerves (1-2 mm diameter). Two burst of three sinusoidal pulses (6 milliamp, 50 millisecond on/100 millisecond off) were applied through the electrode.

The sensor probe was guided by hand, exploring tissues surrounding the nerve fiber starting at a region about 5 centimeters from the stimulation point.

Results

The goat peroneal nerve was stimulated via Two burst of three sinusoidal pulses (6 milliamp, 50 millisecond on/100 millisecond off). The sensor was placed percutaneously at two locations, first at an estimated nerve fiber location and then approximately two centimeters away from the nerve fiber. When positioned at an estimated nerve fiber location (Figure 6B), the sensor response over time (X axis; capacitance - y axis) appears as a pair of well defined three-peak regions which correlate with the stimulation signal. When positioned 2 centimeters away from the estimated nerve location, the sensor produces two peak regions of low amplitude that correlates with the stimulation signal (Figure 6C). These results indicate that the response of the capacitance sensor of the present invention can be correlated to sensor distance from the nerve fiber.

It is appreciated that certain features of the invention, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the invention, which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable subcombination.

Although the invention has been described in conjunction with specific embodiments thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art. Accordingly, it is intended to embrace all such alternatives, modifications and variations that fall within the spirit and broad scope of the appended claims. All publications, patents and patent applications mentioned in this specification are herein incorporated in their entirety by reference into the specification, to the same extent as if each individual publication, patent or patent application was specifically and individually indicated to be incorporated herein by reference. In addition, citation or identification of any reference in this application shall not be construed as an admission that such reference is available as prior art to the present invention.

Claims

WHAT IS CLAIMED IS:

1. A device for locating nerve fibers in a tissue comprising:

(a) a probe including a distal tip having at least one capacitance sensor; and

(b) a processing unit for:

(i) collecting data from said at least one capacitive sensor; and

(ii) determining displacement of nerve fibers with respect to said distal tip on said data.

2. The device of claim 1, wherein said distal tip is covered with insulative material.

3. The device of claim 1, wherein said at least one capacitance sensor includes an array of capacitance sensors.

4. The device of claim 1, wherein said processing unit is also configured for determining a type of nerve fibers based on said data.

5. The device of claim 1, further comprising a user interface for providing feedback relating to a proximity of the nerve fibers to said distal tip.

6. The device of claim 1, wherein (ii) is effected by comparing said data to known values.

7. The device of claim 1, wherein said data is derived from a capacitance waveform.

8. The device of claim 1, wherein said data includes resonance or impedance data.

9. The device of claim 1, wherein said distal tip is configured for intraarticular use.

10. The device of claim 1, further comprising at least one electrode for electrically stimulating tissue.

11. The device of claim 3, wherein said array includes at least two capacitance sensors having directional capacitance sensing capabilities.

12. The device of claim 3, wherein each of said at least two capacitance sensors has a different directional capacitance sensing.

13. The device of claim 1, wherein each of said capacitance sensors is shaped as a rectangle, square or circle.

14. The device of claim 1, wherein each of said capacitance sensors includes a conducting element coated with a dielectric layer.

15. The device of claim 14, wherein said conducting element is composed of at least one metal selected from the group consisting of stainless steel, iron, aluminum, and copper.

16. The device of claim 1, wherein said at least one capacitance sensor is 0.5- 5 mm thick and 25-250 mm in length.

17. The device of claim 7, wherein said capacitance waveform is a digital waveform.

18. A system comprising the device of claim 1 and a probe for disrupting conductance in the nerve fibers.

19. The system of claim 18, wherein said device and said probe are enclosed in a single housing.

20. The system of claim 18, wherein said probe is a cryoablation probe, a chemical ablation probe, an RF probe or a thermal ablation probe.

21. The system of claim 18, wherein said probe includes a guide for guiding an attachable tissue treatment probe.

22. A system for treating neuropathic pain comprising:

(a) a device for locating nerve fibers in a tissue; and

(b) a probe capable of disrupting conductance in said nerve fibers.

23. The system of claim 22, wherein said device is configured for intraarticular use.

24. The system of claim 22, wherein said nerve fibers are nociceptive afferents.

25. The system of claim 22, wherein said probe is a cryoablation probe, a chemical ablation probe, an RF probe or a thermal ablation probe.

26. The system of claim 22, wherein said device is configured for determining capacitance of tissue.

27. The system of claim 22, wherein said device is configured for determining an electrical field, electroresonance, impedance or capacitance of intraarticular tissue.

28. The system of claim 22, wherein said device and said probe are enclosed in a single housing.

29. The system of claim 22, further comprising a processing unit for controlling operation of said probe within said tissue space based on said mapping of said nerve fibers.

30. The system of claim 22, further comprising a processing unit for providing feedback on quality of disrupting conductance in said nerve fibers.

31. A method of treating neuropathic pain comprising:

(a) electrically stimulating a tissue;

(b) using a capacitance sensor to measure capacitance changes resulting from said electrical stimulation thereby locating nerve fibers in a tissue; and

(c) disrupting conductance of said nerve fibers.

32. The method of claim 31, further comprising assessing conductance of said nerve fibers following (c).