Patent ID: 12226149

DETAILED DESCRIPTION

Reference will now be made in detail to one or more embodiments of the disclosure, examples of the disclosure, examples of which are illustrated in the drawings. Each example and embodiment is provided by way of explanation of the disclosure, and is not meant as a limitation of the disclosure. For example, features illustrated or described as part of one embodiment may be used with another embodiment to yield still a further embodiment. It is intended that the disclosure include these and other modifications and variations as coming within the scope and spirit of the disclosure.

Before explaining at least one embodiment of the disclosure in detail, it is to be understood that the disclosure is not limited in its application to the details of construction and the arrangement of the components set forth in the following description or illustrated in the drawings. The disclosure 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.

For the purposes of this disclosure, a lesion refers to any effect achieved through the application of energy to a tissue in a patient's body, and the disclosure is not intended to be limited in this regard. Furthermore, for the purposes of this description, proximal generally indicates that portion of a device or system next to or nearer to a user (when the device is in use), while the term distal generally indicates a portion further away from the user (when the device is in use).

Referring now to the drawings,FIG.1illustrates a schematic diagram of one embodiment of an ablation system100for treating tissue in a patient's body according to example aspects of the present disclosure. As shown, the ablation system100includes a generator102, a controller120communicatively coupled to the generator102, at least one probe assembly106having a plurality of probes107coupled to the generator, e.g. via cable104, and one or more cooling devices108. More specifically, as shown in the illustrated embodiment, the ablation system100includes four probes107. It should be understood that the ablation system100may include any suitable number of probes107, including one probe up to four probes and more.

In addition, as shown in the illustrated embodiment, the generator102may be a radio frequency (RF) generator, but may optionally be any energy source that may deliver other forms of energy, including but not limited to microwave energy, thermal energy, ultrasound and optical energy. In one embodiment, the generator102is operable to communicate with one more devices, for example with the probes107and the one or more cooling devices108. Such communication may be unidirectional or bidirectional depending on the devices used and the procedure performed. In addition, as shown, the cooling devices108may be coupled to the generator102via a pump cable110. Further, as shown, the ablation system10may also include one or more proximal cooling supply tubes112and one or more proximal cooling return tubes114.

In addition, as shown, a distal region124of the cable104may include a splitter130that divides the cable104into two distal ends136such that the probes107can be connected thereto. A proximal end128of the cable104is connected to the generator102. This connection can be permanent, whereby, for example, the proximal end128of the cable104is embedded within the generator102, or temporary, whereby, for example, the proximal end128of cable104is connected to generator102via an electrical connector. The two distal ends136of the cable104terminate in connectors140operable to couple to the probes107and establish an electrical connection between the probes107and the generator102. In alternate embodiments, the system100may include a separate cable for each probe assembly106being used to couple the probes107to the generator102. Alternatively, the splitter130may include more than two distal ends. Such a connector is useful in embodiments having more than two devices connected to the generator102, for example, if more than two probe assemblies are being used.

The cooling device(s)108may include any means of reducing a temperature of material located at and proximate to one or more of the probes107. For example, the cooling devices108may include one or more peristaltic pumps operable to circulate a fluid from the cooling devices108through one or more proximal cooling supply tubes112, the probes107, one or more proximal cooling return tubes114and back to the one or more cooling devices108. The fluid may be water or any other suitable fluid.

Referring toFIGS.1and2, the controller120is configured for facilitating communication between the various components of the system100. For example, in one embodiment, the controller120facilitates communication between the cooling devices108and the generator102. In this way, feedback control is established between the cooling device(s)108and the generator102. The feedback control may include the generator102, the probes107, and the cooling devices108, although any feedback between any devices is within the scope of the present disclosure. The feedback control may be implemented, for example, in a control module which may be a component of the generator102or separate from the generator102. In such embodiments, the generator102is operable to communicate bi-directionally with the probes107as well as with the cooling devices108. In the context of this disclosure, bi-directional communication refers to the capability of a device to both receive a signal from and send a signal to another device.

Further, as shown particularly inFIG.2, the controller120may include one or more processor(s)200and associated memory device(s)202configured to perform a variety of computer-implemented functions (e.g., performing the methods, steps, calculations and the like and storing relevant data as disclosed herein). Moreover, the memory device(s)202may be configured to store computer-readable instructions that when executed by the one or more processors200cause the one or more processors200to perform operations. For example, in one embodiment, the operations may include detecting a number of probes107connected to the generator102and allocating a portion of its power supply to each of the probes107based on the number of probes detected.

Additionally, the controller120may also include a communications module204to facilitate communications between the controller120and the various components of the system100, e.g. any of the components ofFIG.1. Further, the communications module204may include a sensor interface206(e.g., one or more analog-to-digital converters) to permit signals transmitted from one or more sensors208,210to be converted into signals that can be understood and processed by the processors200. It should be appreciated that the sensors208,210may be communicatively coupled to the sensor interface206using any suitable means. For example, as shown, the sensors208,210may be coupled to the sensor interface206via a wired connection. However, in other embodiments, the sensors208,210may be coupled to the sensor interface206via a wireless connection, such as by using any suitable wireless communications protocol known in the art. As such, the processor200may be configured to receive one or more signals from the sensors208,210.

As used herein, the term “processor” refers not only to integrated circuits referred to in the art as being included in a computer, but also refers to a controller, a microcontroller, a microcomputer, a programmable logic controller (PLC), an application specific integrated circuit, and other programmable circuits. The processor200is also configured to compute advanced control algorithms and communicate to a variety of Ethernet or serial-based protocols (Modbus, OPC, CAN, etc.). Additionally, the memory device(s)202may generally include memory element(s) including, but not limited to, computer readable medium (e.g., random access memory (RAM)), computer readable non-volatile medium (e.g., a flash memory), a floppy disk, a compact disc-read only memory (CD-ROM), a magneto-optical disk (MOD), a digital versatile disc (DVD) and/or other suitable memory elements. Such memory device(s)202may generally be configured to store suitable computer-readable instructions that, when implemented by the processor(s)200, configure the controller120to perform the various functions as described herein.

As an example, the controller120may receive temperature measurements from one or more of the plurality of probes107. Based on the temperature measurements, the controller120may perform some action, such as modulating the power that is sent to the probes107. Thus, the probes107may be individually controlled based on their respective temperature measurements. For example, power to each of the probes107can be increased when a temperature measurement is low or decreased when a measurement is high. This variation of power may be different for each probe assembly. In some cases, the controller120may terminate power to one or more probes107. Thus, the controller120may receive a signal (e.g. temperature measurement) from one or more of probes107, determine the appropriate action, and send a signal (e.g. decreased or increased power) back to one or more of the probes107. Alternatively, the controller120may send a signal to the cooling devices108to either increase or decrease the flow rate or degree of cooling being supplied to one or more of the probes107.

In several embodiments, the cooling devices108may reduce the rate of cooling or disengage depending on the distance between the probes107. For example, when the distance is small enough such that a sufficient current density exists in the region to achieve a desired temperature, little or no cooling may be required. In such an embodiment, energy is preferentially concentrated between the energy delivery devices192through a region of tissue to be treated, thereby creating a strip lesion. A strip lesion is characterized by an oblong volume of heated tissue that is formed when an active electrode is near a return electrode of similar dimensions. This occurs because at a given power, the current density is preferentially concentrated between the electrodes and a rise in temperature results from current density.

The cooling devices108may also communicate with the generator102and/or the controller120to alert the generator102to one or more possible errors and/or anomalies associated with the cooling devices108. For example, if cooling flow is impeded or if a lid of one or more of the cooling devices108is opened. The controller120may then act on the error signal by at least one of alerting a user, aborting the procedure and modifying an action.

Still referring toFIG.1, the proximal cooling supply tubes112may include proximal supply tube connectors116at the distal ends of the one or more proximal cooling supply tubes112. Additionally, the proximal cooling return tubes114may include proximal return tube connectors118at the distal ends of the one or more proximal cooling return tubes114. In one embodiment, the proximal supply tube connectors116are female luer-lock type connectors and the proximal return tube connectors118are male luer-lock type connectors although other connector types are intended to be within the scope of the present disclosure.

In addition, as shown inFIG.1, each of the probes107may include a proximal region160, a handle180, a hollow elongate shaft184, and a distal tip region190that includes the one or more energy delivery devices192. Further, as shown, the proximal region160includes a distal cooling supply tube162, a distal supply tube connector166, a distal cooling return tube164, a distal return tube connector168, a probe assembly cable170, and a probe cable connector172. In such embodiments, the distal cooling supply tube162and distal cooling return tube164are flexible to allow for greater maneuverability of the probes107, but alternate embodiments with rigid tubes are possible.

Further, in several embodiments, the distal supply tube connector166may be a male luer-lock type connector and the distal return tube connector168may be a female luer-lock type connector. Thus, the proximal supply tube connector116may be operable to interlock with the distal supply tube connector166and the proximal return tube connector118may be operable to interlock with the distal return tube connector168.

The probe cable connector172may be located at a proximal end of the probe assembly cable170and may be operable to reversibly couple to one of the connectors140, thus establishing an electrical connection between the generator102and the probe assembly106. The probe assembly cable170may include one or more conductors depending on the specific configuration of the probe assembly106. For example, in one embodiment, the probe assembly cable170may include five conductors allowing probe assembly cable170to transmit RF current from the generator102to the one or more energy delivery devices192as well as to connect multiple temperature sensing devices to the generator102as discussed below.

The energy delivery devices192may include any means of delivering energy to a region of tissue adjacent to the distal tip region190. For example, the energy delivery devices192may include an ultrasonic device, an electrode or any other energy delivery means and the disclosure is not limited in this regard. Similarly, energy delivered via the energy delivery devices192may take several forms including but not limited to thermal energy, ultrasonic energy, radiofrequency energy, microwave energy or any other form of energy. For example, in one embodiment, the energy delivery devices192may include an electrode. The active region of the electrode may be 2 to 20 millimeters (mm) in length and energy delivered by the electrode is electrical energy in the form of current in the RF range. The size of the active region of the electrode can be optimized for placement within an intervertebral disc, however, different sizes of active regions, all of which are within the scope of the present disclosure, may be used depending on the specific procedure being performed. In some embodiments, feedback from the generator102may automatically adjust the exposed area of the energy delivery device192in response to a given measurement such as impedance or temperature. For example, in one embodiment, the energy delivery devices192may maximize energy delivered to the tissue by implementing at least one additional feedback control, such as a rising impedance value.

Referring now toFIG.3, a perspective cut-away view of one embodiment of the distal tip region190of the probe assembly106is illustrated. As shown, the distal tip region190includes one or more temperature sensing elements402which are operable to measure the temperature at and proximate to the one or more energy delivery devices192. The temperature sensing elements402may include one or more thermocouples, thermometers, thermistors, optical fluorescent sensors or any other means of sensing temperature. In one embodiment, the temperature sensing elements402are connected to the generator102via probe assembly cable170and cable104although any means of communication between the temperature sensing elements402and the generator102, including wireless protocols, are included within the scope of the present disclosure. More specifically, as shown, the temperature sensing element(s)402may include a thermocouple junction made by joining a stainless steel hypotube406to a constantan wire410, wherein the constantan wire410is insulated by insulation412. In this embodiment, the junction of hypotube406and the constantan wire410is made by laser welding, although any other means of joining two metals may be used. Furthermore, in this embodiment, the hypotube406and the constantan wire410extend through a lumen of the elongate shaft184and connect to the probe assembly cable170within the handle180.

Further, as shown, the temperature sensing element402of each probe107protrudes beyond the energy delivery device192. Placing the temperature sensing elements402at this location, rather than within a lumen450defined by the energy delivery device192, is beneficial because it allows the temperature sensing element402to provide a more accurate indication of the temperature of tissue proximate to the energy delivery device192. This is due to the fact that, when extended beyond the energy delivery device192, the temperature sensing element402will not be as affected by the cooling fluid flowing within the lumen450as it would be were it located within lumen450. Thus, in such embodiments, the probe assembly106includes a protrusion protruding from the distal region of the probe assembly, whereby the protrusion is a component of the temperature sensing element402.

Referring still toFIG.3, the probes107may further include one or more secondary temperature sensing elements404located within the elongate shaft184at some distance away from the energy delivery device192, and positioned adjacent a wall of the elongate shaft184. The secondary temperature sensing elements404may similarly include one or more thermocouples, thermometers, thermistors, optical fluorescent sensors or any other means of sensing temperature. For example, as shown, the secondary temperature sensing element404is a thermocouple made by joining copper and constantan thermocouple wires, designated as420and422respectively. Further, in certain embodiments, the copper and constantan wires420and422may extend through a lumen of the elongate shaft184and may connect to the probe assembly cable170within the handle180.

In addition, the probes107may further include a thermal insulator430located proximate to any of the temperature sensing elements402,404. As such, the thermal insulator430may be made from any thermally insulating material, for example silicone and may be used to insulate any temperature sensing element from other components of the probe assembly106, so that the temperature sensing element will be able to more accurately measure the temperature of the surrounding tissue. More specifically, as shown, the thermal insulator430is used to insulate the temperature sensing element404from cooling fluid passing through the shaft supply tube302and the shaft return tube304.

In further embodiments, the probes107may also include a radiopaque marker440incorporated somewhere along the elongate shaft184. For example, as shown inFIG.3, an optimal location for a radiopaque marker may be at or proximate to the distal tip region190, adjacent the energy delivery device192. The radiopaque markers are visible on fluoroscopic x-ray images and can be used as visual aids when attempting to place devices accurately within a patient's body. These markers can be made of many different materials, as long as they possess sufficient radiopacity. Suitable materials include, but are not limited to silver, gold, platinum and other high-density metals as well as radiopaque polymeric compounds. Various methods for incorporating radiopaque markers into or onto medical devices may be used, and the present disclosure is not limited in this regard.

Referring now toFIG.4, the ablation system100of the present disclosure may further include one or more introducer tubes802. Generally, introducer tubes may include a proximal end, a distal end, and a longitudinal bore extending therebetween. Thus, the introducer tubes802(when used) are operable to easily and securely couple with the probes107. For example, the proximal end of the introducer tubes802may be fitted with a connector able to mate reversibly with handle180of one of the probes107. An introducer tube802may be used to gain access to a treatment site within a patient's body and a hollow elongate shaft184of a probe107may be introduced to the treatment site through the longitudinal bore of the introducer tube802. The introducer tubes802may be made of various materials, as is known in the art and, if the material is electrically conductive, the introducer tubes may be electrically insulated along all or part of their length, to prevent energy from being conducted to undesirable locations within a patient's body. In some embodiments, the elongate shaft184may be electrically conductive, and an introducer tube802may function to insulate the shaft184leaving the energy delivery device192exposed for treatment.

In additional embodiments, the ablation system100may also include one or more stylets. A stylet may have a beveled tip to facilitate insertion of the one or more introducer tubes into a patient's body. Various forms of stylets are well known in the art and the present disclosure is not limited to include only one specific form. Further, as described above with respect to the introducer tubes, the stylets may be operable to connect to a power source and may therefore form part of an electrical current impedance monitor. In other embodiments, one or more of the probes107may form part of an electrical current impedance monitor. Thus, the controller120may receive impedance measurements from one or more of the stylets, the introducer tubes, and/or the probes107and may perform an action, such as alerting a user to an incorrect placement of an energy delivery device192, based on the impedance measurements.

In one embodiment, the plurality of probes107may be operated in a bipolar mode. For example,FIG.4illustrates one embodiment of two probes107, wherein the distal tip regions190thereof are located within an intervertebral disc800. In such embodiments, electrical energy is delivered to the probes107and this energy is preferentially concentrated therebetween through a region of tissue to be treated (i.e. an area of the intervertebral disc800). The region of tissue to be treated is thus heated by the energy concentrated between the probes107. In other embodiments, the probes107may be operated in a monopolar mode, in which case an additional grounding pad is required on the surface of a body of a patient, as is known in the art. Any combination of bipolar, monopolar, or other suitable treatment procedures may also be used. Further, as mentioned, it should be understood that the system100may include more than two probes107. For example, in some embodiments, three probes107may be used and the probes107may be operated in a triphasic mode, whereby the phase of the current being supplied differs for each probe107.

Referring now toFIG.5, a flow diagram of one embodiment of a method500for treating tissue of a patient's body, such as an intervertebral disc800, using the ablation system100described herein is illustrated. As shown at502, the method500may include providing an energy source and a controller coupled to a probe assembly106. Further, the energy source, e.g. the generator102, has a predetermined power supply. For example, in one embodiment, the predetermined power supply may be up to 80 watts (W).

As shown at504, the method500includes detecting, via the controller120, a number of probes107of the probe assembly106connected to the energy source. As shown506, the method500includes inserting the plurality of probes107into the patient's body. As shown at508, the method500includes positioning the plurality of probes107at or near the tissue of the patient's body to be treated. For example, in one embodiment, with a patient lying on a radiolucent table, fluoroscopic guidance may be used to percutaneously insert an introducer with a stylet to access the posterior of an intervertebral disc800. In addition to fluoroscopy, other aids, including but not limited to impedance monitoring and tactile feedback, may be used to assist a user to position the introducer and/or probes107within the patient's body.

Referring still toFIG.5, as shown at510, the method500may also include allocating, via the energy source102, a portion of the predetermined power supply to each of the probes107based on the number of probes detected of probes107. More specifically, in one embodiment, the predetermined power supply may be equally divided amongst each of the probes107. As such, the independent control and higher power levels allow each probe107to receive an equal amount of power per channel. For example, when two or more probes are connected to the generator102, the power may be evenly divided amongst the probes107at the beginning of a treatment procedure. Therefore, for a two-probe procedure utilizing an 80-watt generator, each probe107may have has access to 40 W. Similarly, for three- and four-probe procedures, each probe107may have access to 27 W and 20 W, respectively.

As shown at512, the method500further includes treating the tissue by controlling the probes107based on the allocated power. For example, in one embodiment, the method500may include operating each of the probes107in an independent state. Thus, individual treatment procedures for each of the probes107may be independently started or stopped without affecting the available power to remaining probes107, thereby avoiding entanglement of temperature feedback control on each probe107. In further embodiments, the ablation system100may cycle through a treatment procedure for one or more of the probes107. More specifically, in certain embodiments, the method500may include activating the individual treatment procedures for each of the probes in a sequential order. In addition, the ablation system100may omit cycling through treatment procedures of probes107that do not have an available power above a certain threshold, thereby maximizing energy availability. This setup eliminates dependencies due to power sharing across active probes. In several embodiments, the ablation system100may control power supplied to each of the probes107as a function of a temperature of that probe.

Referring now toFIG.6, a probe assembly106having four probes107, namely Probe A, Probe B, Probe C, and Probe D, is illustrated to further illustrated example aspects of the present disclosure. The independent states described herein may correspond to a “ready” state, an “on” state, or a “complete” state. Probe A is in the “on” state, whereas Probes B, C, and Dare in the “ready” state. Further, as shown, each probe has access to the RF source102during its respective time slot via, e.g. switches109. Thus, in certain embodiments, the system100may limit power, voltage, or current supplied by the generator102to one or more of the probes107. For example, in one embodiment, the generator102may limit the power supplied to a single probe or probe pair of the probe assembly to 50 watts or less. In such embodiments, the system100can be operated in a bipolar mode (where probes act in pairs instead of individually). As such, a single pair of probes may be limited to 50 W (similar to a single probe situation), whereas two probe pairs may be limited to 40 W each (similar to a two-probe situation).

During the “ready” state, a connected probe107is not active (i.e. the probe107is not delivering energy). As used herein, a connected probe generally refers to a probe for which a valid thermocouple detected. As such, the “ready” state is characterized by low-power impedance measurements on all connected probes107. In addition, one or more bursts of low-voltage output may be provided to the connected probes such that the RF voltage and current can be measured. Thus, the probe impedance and temperature can also be computed during the “ready” state as a function of the measured RF voltage and current. During the “on” state, the connected probe107is active (i.e. the probe107is delivering energy). As used herein, an active probe generally refers to a probe to which RF output is delivered. For a single active probe operating in the “on” state, RF output is delivered continuously under temperature feedback control as described herein and is subject to RF output limits. For multiple probes, RF output is delivered for a certain time period corresponding to each active probe107. In such embodiments, the amplitude of the RF during each time period can be controlled by the temperature feedback loop corresponding to that probe107and is subject to RF output limits. In addition, low-power impedance measurements can continue to be made on all non-active, connected probes107, with one or more bursts of low-voltage output being provided at the beginning of the time period corresponding to the non-active, connected probe(s)107. Thus, the RF voltage and current can be measured and the probe impedance can be computed therefrom. In addition, during the “on” state, the RF power can be measured for each connected probe107. During the “complete” state, the connected probe(s)107is non-active (i.e. RF energy delivery is turned off). As used hereon, a non-active probe generally refers to a connected probe to which no RF output is delivered. In addition, the final measured values are maintained and the system100proceeds to the “ready” state after a certain time period or when the active area corresponding to the probe107is pressed.

During the individual treatment procedures, a treatment protocol such as the cooling supplied to the respective probe107and/or the power transmitted to the probe107may be adjusted and/or controlled to maintain a desirable treatment area shape, size and uniformity. More specifically, the method500may include actively controlling energy delivered to the tissue by controlling both an amount of energy delivered through the energy delivery devices192and individually controlling the flow rate of the cooling devices108. In further embodiments, the generator102may control the energy delivered to the tissue based on the measured temperature measured by the temperature sensing element(s)402and/or impedance sensors.

More specifically, as shown inFIG.7, a block diagram of one embodiment of a treatment procedure for treating a patient's tissues is illustrated. As shown at600, ablation is initialized. As shown at602, the energy dosage may be calculated using simple numerical integration techniques. As shown at604, the calculated energy dosage may then be compared against a preset energy dosage threshold. If the dosage is not satisfied as shown at606, the procedure continues to608to mitigate rising impedance of the internally-cooled probes107during the treatment procedure. More specifically, as shown, one or more procedure parameters are monitored while delivering the energy from the generator102to the tissue through the energy delivery devices192. The procedure parameter(s) described herein may include, for example, a temperature of the tissue, an impedance of the tissue, a power demand of the energy delivery device192, or similar, or combinations thereof. Further, as shown, the procedure parameter(s)608may be fed into a rising impedance detection engine610. As shown at612, the rising impedance detection engine610is configured to determine, e.g. in real-time, whether a rising impedance event is imminent based on the received procedure parameter(s)608. The rising impedance detection engine610can then determine a command for the cooling devices108based on whether the rising impedance event is likely to occur in the predetermined time period.

If not imminent, as shown at614, the cooling rate can be increased, e.g. by increasing pump speed of the cooling devices108as shown at616. After the cooling rate is increased, the ablation600continues. If a rising impedance event is imminent, as shown at618, the cooling rate can be reduced, e.g. by decreasing the pump speed of the cooling devices108as shown at620. Further, as shown, the system operates using closed-loop feedback control634,636.

Once the energy dosage threshold is satisfied, as shown at622, the treatment procedure is configured to check if the thermal dosage threshold has been satisfied as shown at624. If the thermal dosage has not been satisfied, as shown at626, the treatment procedure proceeds through the independent temperature-power feedback control loop as shown at628. More specifically, in certain embodiments, the amount of energy delivered through the energy delivery device192may be controlled by defining a predetermined threshold temperature for treating the tissue, ramping up the temperature of the tissue via the generator102through the energy delivery device192to the predetermined threshold temperature, and maintaining the temperature of the tissue at the predetermined threshold temperature to create a lesion in the tissue. In such embodiments, the temperature of the tissue may be maintained at the predetermined threshold temperature as a function of at least one of a power ramp rate, an impedance level, an impedance ramp rate, and/or a ratio of impedance to power.

Only when the thermal dosage threshold has been satisfied, as shown at630, the procedure terminates as shown at632. Following treatment, energy delivery and cooling may be stopped and the probes107are removed from the introducers, where used. A fluid such as an antibiotic or contrast agent may be injected through the introducers, followed by removal of the introducers. Alternatively, the distal tips of the probes107may be sharp and sufficiently strong to pierce tissue so that introducers may not be required. As mentioned above, positioning the probes107, and more specifically the energy delivery devices192, within the patient's body, may be assisted by various means, including but not limited to fluoroscopic imaging, impedance monitoring and tactile feedback. Additionally, some embodiments of this method may include one or more steps of inserting or removing material into a patient's body.

A system of the present disclosure may be used in various medical procedures where usage of an energy delivery device may prove beneficial. Specifically, the system of the present disclosure is particularly useful for procedures involving treatment of back pain, including but not limited to treatments of tumors, intervertebral discs, facet joint denervation, sacroiliac joint lesioning or intraosseous (within the bone) treatment procedures. Moreover, the system is particularly useful to strengthen the annulus fibrosus, shrink annular fissures and impede them from progressing, cauterize granulation tissue in annular fissures, and denature pain-causing enzymes in nucleus pulposus tissue that has migrated to annular fissures. Additionally, the system may be operated to treat a herniated or internally disrupted disc with a minimally invasive technique that delivers sufficient energy to the annulus fibrosus to breakdown or cause a change in function of selective nerve structures in the intervertebral disc, modify collagen fibrils with predictable accuracy, treat endplates of a disc, and accurately reduce the volume of intervertebral disc tissue. The system is also useful to coagulate blood vessels and increase the production of heat shock proteins.

Using liquid-cooled probes107with an appropriate feedback control system as described herein also contributes to the uniformity of the treatment. The cooling distal tip regions190of the probes107helps to prevent excessively high temperatures in these regions which may lead to tissue adhering to the probes107as well as an increase in the impedance of tissue surrounding the distal tip regions190of the probes107. Thus, by cooling the distal tip regions190of the probes107, higher power can be delivered to tissue with a minimal risk of tissue charring at or immediately surrounding the distal tip regions190. Delivering higher power to energy delivery devices192allows tissue further away from the energy delivery devices192to reach a temperature high enough to create a lesion and thus the lesion will not be limited to a region of tissue immediately surrounding the energy delivery devices192but will rather extend preferentially from a distal tip region190of one probe assembly106to the other.

It should be noted that the term radiopaque marker as used herein denotes any addition or reduction of material that increases or reduces the radiopacity of the device. Furthermore, the terms probe assembly, introducer, stylet etc. are not intended to be limiting and denote any medical and surgical tools that can be used to perform similar functions to those described. In addition, the disclosure is not limited to be used in the clinical applications disclosed herein, and other medical and surgical procedures wherein a device of the present disclosure would be useful are included within the scope of the present disclosure.

It is appreciated that certain features of the disclosure, 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 disclosure, which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable subcombination.

Although the disclosure 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.

This written description uses examples to disclose the disclosure, including the best mode, and also to enable any person skilled in the art to practice the disclosure, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the disclosure is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they include structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.