Skin condition monitor and method for using the same in electrosurgical equipment

Abstract

A skin condition monitoring device is provided, which includes one or more sensors for sensing the energy density applied to a surgical site in real time based on one or more monitored variables. Based on the sensed applied energy density, the applied power level of the cold plasma beam can be adjusted so that the energy density applied to the surgical site remains within a beneficial range for achieving the desired physiological effect on the surgical site. The skin condition monitoring device of the present disclosure can be connected to the distal end of an electrosurgical device capable of generating cold plasma.

Description

[0001] priority

[0002] This application claims priority to U.S. Provisional Patent Application No. 62 / 620,551, filed on January 23, 2018, entitled “SKIN STATUS MONITOR AND METHOD THERE OF FORELECTRO SURGICAL APPARATUSES,” the contents of which are incorporated herein by reference in their entirety. Technical Field

[0003] The present disclosure relates generally to electrosurgery and electrosurgical systems and devices, and more particularly, to skin condition monitoring devices for use with electrosurgical devices in cold plasma applications. Background Art

[0004] High frequency electrical energy has been widely used in surgery. Electrosurgical energy is used to cut tissue and coagulate body fluids.

[0005] Electrosurgical instruments generally include either "monopolar" devices or "bipolar" devices. A monopolar device includes an active electrode on the electrosurgical instrument with a return electrode attached to the patient. In monopolar electrosurgery, electrosurgical energy flows through the patient's body through the active electrode on the instrument to the return electrode. Such monopolar devices are effective in surgical procedures where both cutting and coagulation of tissue are desired and where stray currents do not pose a substantial risk to the patient.

[0006] A bipolar device includes an active electrode and a return electrode on a surgical instrument. In a bipolar electrosurgical device, electrosurgical energy flows through the active electrode to the patient's tissue, through a short distance through the tissue to the return electrode. The electrosurgical effect is substantially confined to a small area of ​​tissue between the two electrodes disposed on the surgical instrument. Bipolar electrosurgical devices have been found to be useful for surgical procedures where stray currents could pose a hazard to the patient, or where other procedural considerations require close proximity of the active and return electrodes. Surgical procedures involving bipolar electrosurgery often require methods and procedures that differ significantly from those involving monopolar electrosurgery.

[0007] Gas plasma is an ionized gas that can conduct electrical energy. Plasma is used in surgical devices to conduct electrosurgical energy to a patient. Plasma conducts energy by providing a relatively low resistance path. The electrosurgical energy will follow through the plasma to cut, coagulate, dry or cauterize the patient's blood or tissue. No physical contact is required between the electrode and the tissue being treated.

[0008] Electrosurgical systems that do not include a source of regulated gas can ionize the ambient air between the active electrode and the patient. The resulting plasma will conduct electrosurgical energy to the patient, although the plasma arc will generally appear more spatially dispersed than in systems with a regulated ionizable gas stream.

[0009] Atmospheric pressure discharge cold plasma applicators have been used in a variety of applications, including surface disinfection, hemostasis, and tumor ablation. In the latter example, the process can be relatively slow, generate large amounts of noxious smoke from vaporized and charred tissue, and can cause collateral damage to surrounding healthy tissue when high-power electrosurgical energy is used. Exact accuracy can also be an issue due to the width of the plasma beam. Summary of the invention

[0010] The present disclosure provides a skin condition monitoring device, which includes one or more sensors for sensing the energy density applied to a surgical site in real time based on one or more monitored variables. The skin condition monitoring device of the present disclosure is connected to the distal tip of an electrosurgical device capable of generating cold plasma. Based on the sensed applied energy density, the applied power level of the cold plasma beam can be adjusted so that the energy density applied to the surgical site remains within a beneficial range for achieving a desired physiological effect on the surgical site.

[0011] In one aspect of the present disclosure, an electrosurgical device is provided, comprising: an applicator including a distal tip, the applicator being configured to generate plasma and eject the generated plasma from the distal tip; and a support device, the support device comprising an applicator receiving portion, at least one post and a base, the at least one post connecting the applicator receiving portion to the base, and the applicator receiving portion being configured to receive the distal portion of the applicator so that when the base contacts the tissue surface, the distal tip of the applicator is disposed at a predetermined fixed distance from the tissue surface through a hole in the applicator receiving portion.

[0012] According to one aspect of the electrosurgical device, the base is configured in an annular shape having a hole, and the distal tip is oriented such that plasma is applied to the tissue surface through the hole of the base.

[0013] According to one aspect of the electrosurgical apparatus, the base includes at least one sensor for monitoring at least one variable associated with the tissue surface when the base contacts the tissue surface.

[0014] According to one aspect of the electrosurgical device, the electrosurgical device also includes at least one controller configured to determine an energy density applied by the plasma to the tissue surface based on the monitored at least one variable and to adjust the applied power level of the plasma based on the determined energy density.

[0015] According to one aspect of the electrosurgical apparatus, the at least one controller is configured to adjust the applied power level of the plasma such that the energy density applied to the tissue surface remains within a predetermined beneficial range to achieve a desired physiological effect.

[0016] According to one aspect of the electrosurgical device, the electrosurgical device further comprises at least one controller configured to determine at least one of a direction and / or a speed of movement of the distal tip of the applicator relative to the tissue surface based on the at least one variable.

[0017] According to one aspect of the electrosurgical device, the at least one sensor is a ring sensor.

[0018] According to one aspect of the electrosurgical apparatus, the at least one sensor comprises a sensor array.

[0019] According to one aspect of the electrosurgical device, the electrosurgical device further comprises circuitry configured to serialize measurement data received from the sensor array and output the measurement data to the at least one controller via a single line.

[0020] According to one aspect of the electrosurgical apparatus, the at least one sensor is a temperature sensor and the at least one variable is the temperature of the tissue surface.

[0021] According to one aspect of the electrosurgical device, the at least one sensor comprises at least first and second contact electrodes.

[0022] According to one aspect of the electrosurgical device, the electrosurgical device also includes a circuit including at least one controller, which is configured to apply a detection signal to the first and second contact electrodes and measure the voltage and current of the first and second contact electrodes, and the at least one controller is configured to determine tissue impedance based on the voltage and current measurement results of the first and second contact electrodes, and adjust the applied power level of the plasma based on the determined tissue impedance.

[0023] According to one aspect of the electrosurgical device, the electrosurgical device further comprises a circuit including at least one controller configured to apply a detection signal to the first and second contact electrodes and to measure a voltage and a current of the first and second contact electrodes, the at least one controller being configured to determine a phase shift between the voltage and the current of the first and second contact electrodes and to adjust an applied power level of the plasma based on the determined phase shift.

[0024] According to one aspect of the electrosurgical device, the at least one sensor includes at least first and second acoustic transducers, and the electrosurgical device also includes a circuit configured to apply electrical oscillations to the first acoustic transducer so that acoustic emissions are emitted from the first acoustic transducer into the tissue surface and are received by the second acoustic transducer, and the circuit is also configured to determine the acoustic impedance of the tissue surface based on the distance between the first and second acoustic transducers and the flight time of the acoustic emissions emitted between the first and second acoustic transducers, and adjust the applied power level of the plasma based on the determined acoustic impedance.

[0025] According to one aspect of the electrosurgical device, the at least one sensor includes at least first and second acoustic transducers, and the electrosurgical device also includes a circuit configured to apply electrical oscillations to the first acoustic transducer so that acoustic emissions are emitted from the first acoustic transducer into the tissue surface and received by the second acoustic transducer, and the circuit is also configured to determine the acoustic absorption of the tissue surface based on the amplitude of the acoustic signal received by the second acoustic transducer, and adjust the applied power level of the plasma based on the determined acoustic impedance.

[0026] According to one aspect of the electrosurgical device, the electrosurgical device further comprises at least one sensor for determining an electrical impedance of the plasma and at least one controller configured to adjust an applied power level of the plasma based on the determined electrical impedance.

[0027] According to one aspect of the electrosurgical device, the electrosurgical device also includes a circuit for determining a phase shift change between a voltage and a current of the plasma and / or a tissue surface, the circuit including at least one controller configured to adjust an applied power level of the plasma based on the determined phase shift change.

[0028] In another aspect of the present disclosure, an electrosurgical device is provided, comprising: an applicator including a distal tip, the applicator being configured to generate plasma and eject the generated plasma from the distal tip onto a tissue surface; an emission collector configured to collect a first type of emission; and at least one controller configured to output a feedback signal to adjust an applied power level of the generated plasma based on the collected emission.

[0029] According to one aspect of the electrosurgical apparatus, a feedback signal is provided to an electrosurgical generator coupled to the applicator.

[0030] According to one aspect of the electrosurgical apparatus, the emission collector is an acoustic tube and the first type of emission is acoustic emission from the plasma.

[0031] According to one aspect of the electrosurgical apparatus, the acoustic tube includes an open end for receiving acoustic emissions, the open end being disposed proximate a distal tip of the applicator.

[0032] According to one aspect of the electrosurgical apparatus, further comprising an acoustic transducer configured to receive the acoustic emissions via the acoustic tube and generate an electrical signal associated with a plasma acoustic emission frequency of the acoustic emissions and provide the electrical signal to the at least one controller.

[0033] According to one aspect of the electrosurgical apparatus, further comprising an amplifier for amplifying the electrical signal provided to the at least one controller and an analog-to-digital converter for digitizing the electrical signal provided to the at least one controller.

[0034] According to one aspect of the electrosurgical apparatus, the at least one controller, amplifier, and analog-to-digital converter are each co-located with the acoustic transducer.

[0035] According to one aspect of the electrosurgical apparatus, the emission collector is an optical fiber and the first type of emission is a spectrum from the plasma.

[0036] According to one aspect of the electrosurgical device, the tip of the optical fiber is disposed proximate to the distal tip of the applicator for collecting the optical spectrum.

[0037] According to one aspect of the electrosurgical apparatus, further comprising an optical interface configured to receive the collected light spectrum and convert the light spectrum into an electrical signal to provide to the at least one controller.

[0038] According to one aspect of the electrosurgical device, it also includes an optical interface configured to receive the collected spectrum, the optical interface including a first bandpass filter and a first light detector, the first bandpass filter is configured to receive the collected spectrum and pass at least one tissue-derived emission component of the spectrum to the first light detector, the first light detector is configured to convert the tissue-derived emission component into a first electrical signal and provide the first electrical signal to the at least one controller.

[0039] According to one aspect of the electrosurgical device, the optical interface also includes a second bandpass filter and a second light detector, the second bandpass filter is configured to receive the collected spectrum and pass at least one emission component associated with the carrier gas of the applicator to the second light detector, and the second light detector is configured to convert the at least one emission component associated with the carrier gas into a second electrical signal and provide the second electrical signal to the at least one controller. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] The above and other aspects, features and advantages of the present disclosure will become more apparent from the following detailed description when considered in conjunction with the accompanying drawings, in which:

[0041] Figure 1 is a diagram of an exemplary monopolar electrosurgical system according to an embodiment of the present disclosure;

[0042] Figure 2A is a schematic diagram of an electrosurgical device according to an embodiment of the present disclosure;

[0043] Figure 2B It is taken along line AA Figure 2A A cross-sectional view of an electrosurgical device is shown;

[0044] Figure 3A is an enlarged cross-sectional view of an electrosurgical device according to an embodiment of the present disclosure;

[0045] Figure 3B The diagram shows a section taken along line BB. Figure 3A A front view of the electrosurgical device shown;

[0046] Figure 4 yes Figure 3A an enlarged cross-sectional view of the electrosurgical device shown with the blade extended;

[0047] Figure 5A FIGURES illustrate tissue heat diffusion distribution generated on a surgical site by a plasma beam with a low energy density distribution according to an embodiment of the present disclosure;

[0048] Figure 5B FIG. 1 illustrates a tissue heat diffusion distribution generated on a surgical site by a plasma beam with a medium energy density distribution according to an embodiment of the present disclosure;

[0049] Figure 5C FIGURES illustrate tissue heat diffusion distribution generated on a surgical site by a plasma beam with a high energy density distribution according to an embodiment of the present disclosure;

[0050] Figure 6 is another illustration of tissue heat diffusion distribution generated by a plasma beam at a surgical site according to an embodiment of the present disclosure;

[0051] Fig. 7A and 7B illustrates a trailing tail of heat dissipation formed by a scanning motion of an electrosurgical device in accordance with an embodiment of the present disclosure;

[0052] Fig. 8A is a side view of a skin condition monitoring device coupled to a distal end of an electrosurgical device according to an embodiment of the present disclosure;

[0053] Figure 8B According to the embodiment of the present disclosure, Fig. 8A a view of a distal end of a skin condition monitoring device;

[0054] Fig. 9 According to the embodiment of the present disclosure Fig. 8A A perspective view of a skin condition monitoring device;

[0055] Fig. 10A The present invention is shown in FIG. Fig. 8A Skin condition monitoring equipment;

[0056] Fig. 10B The present invention is a diagram showing a plurality of separate sensors according to an embodiment of the present invention. Fig. 8A Skin condition monitoring equipment;

[0057] Fig.11A illustrates a plasma beam scan produced by an electrosurgical device having a blade-type electrode according to an embodiment of the present disclosure;

[0058] Fig. 11B is the received plasma beam power observed from a fixed point according to an embodiment of the present disclosure corresponding to Fig.11A Graph of

[0059] Fig. 11C is another illustration of a plasma beam scan produced by an electrosurgical device having a blade-type electrode according to an embodiment of the present disclosure;

[0060] Fig.11D is the received plasma beam power observed from a fixed point according to an embodiment of the present disclosure corresponding to Fig. 11C Graph of

[0061] Fig.12 It is used according to the embodiment of the present disclosure Fig. 8A Circuit block diagram of a skin condition monitoring device;

[0062] Fig.13A illustrates the plasma impedance of a cold plasma beam generated by an electrosurgical device and the tissue impedance of a target tissue site according to an embodiment of the present disclosure;

[0063] Fig. 13B According to the embodiment of the present disclosure Fig.13A Equivalent circuits of plasma impedance and tissue impedance are shown;

[0064] Fig.14 including a graph showing changes in tissue impedance under various electrosurgical conditions according to an embodiment of the present disclosure;

[0065] Fig.15 is a block diagram of a circuit according to an embodiment of the present disclosure;

[0066] Fig.16 illustrates an electrode array disposed on a support base according to an embodiment of the present disclosure;

[0067] Fig.17 is a block diagram of a tissue electrical impedance measurement system according to an embodiment of the present disclosure;

[0068] Fig.18 An array of acoustic transducers disposed on a support base according to an embodiment of the present disclosure is illustrated;

[0069] Fig.19 is a block diagram of an acoustic impedance measurement system according to an embodiment of the present disclosure;

[0070] Fig. 20 is a block diagram of a differential sound absorption measurement system according to an embodiment of the present disclosure;

[0071] Fig.21 An apparatus for measuring plasma acoustic emission according to an embodiment of the present disclosure is illustrated;

[0072] Fig. 22 An apparatus for measuring a plasma emission spectrum according to an embodiment of the present disclosure is illustrated;

[0073] Fig.23 The present invention is illustrated in accordance with an embodiment of the present invention. Fig. 22 An optical interface for use with the apparatus; and

[0074] Fig.24A and Fig. 24B Exemplary tissue-derived light emissions according to embodiments of the present disclosure are illustrated. DETAILED DESCRIPTION

[0075] The preferred embodiments of the present disclosure will be described below with reference to the accompanying drawings. In the following description, well-known functions or structures are not described in detail to avoid obscuring the present disclosure in unnecessary details. In the accompanying drawings and subsequent descriptions, the traditional term "proximal" will refer to the end of a device (such as an instrument, equipment, applicator, handpiece, tweezers, etc.) that is closer to the user, and the term "distal" will refer to the end farther away from the user. In this article, the phrase "connection" is defined as being directly connected to or indirectly connected through one or more intermediate components. Such intermediate components may include hardware- and software-based components.

[0076] Figure 1An exemplary monopolar electrosurgical system 10, generally indicated at 10, is shown, which includes an electrosurgical generator (ESU), generally indicated at 12, for generating energy for the electrosurgical device 10, and a plasma generator 14, generally indicated at 14, for generating a plasma stream 16 and applying it to a surgical site or target area 18 of a patient 20 resting on a conductive plate or support surface 22. The electrosurgical generator 12 includes a transformer 24, generally indicated at 24, which includes a primary and a secondary connected to a power source (not shown) to provide high-frequency electrical energy to the plasma generator 14. Typically, the electrosurgical generator 12 includes an isolated floating potential that is not referenced to any potential. Therefore, current flows between the active electrode and the return electrode. If the output is not isolated, but referenced to "ground", the current can flow to areas with ground potential. If these areas are relatively small in contact area with the patient, undesirable burns may occur.

[0077] The plasma generator 14 includes a handpiece or holder 26 having an electrode 28 disposed at least partially within a fluid flow housing 29 and coupled to a transformer 24 to receive high frequency electrical energy therefrom to at least partially ionize an inert gas fed to the fluid flow housing 29 of the handpiece or holder 26 to generate or produce a plasma stream 16. The high frequency electrical energy is fed from the secondary of the transformer 24 through an active conductor 30 to the electrode 28 (collectively referred to as the active electrode) in the handpiece 26 to produce the plasma stream 16 for application to a surgical site 18 on a patient 20. In addition, a current limiting capacitor 25 is disposed in series with the electrode 28 to limit the amount of current delivered to the patient 20.

[0078] The return path to the electrosurgical generator 12 passes through the tissue and fluids of the patient 20, the conductor plate or support member 22, and the return conductor 32 (collectively referred to as the return electrode) to the secondary of the transformer 24 to complete the isolated floating potential circuit.

[0079] In another embodiment, the electrosurgical generator 12 includes an isolated non-floating potential that is not referenced to any potential. The plasma current flowing back to the electrosurgical generator 12 passes through tissue and body fluids and the patient 20. From there, the return current circuit is completed by a combined external capacitance to the plasma generator handpiece 26, the surgeon, and by displacement current. The capacitance is determined, among other things, by the body size of the patient 20. Such an electrosurgical device and generator are described in co-owned U.S. Patent No. 7,316,682 to Konesky, the entire contents of which are hereby incorporated by reference in their entirety.

[0080] It should be understood that the transformer 24 can be disposed in the plasma generator head 26, as will be described in various embodiments below. In this configuration, other transformers can be provided in the generator 12 to provide appropriate voltage and current to the transformer in the head, such as a step-down transformer, a step-up transformer, or any combination thereof.

[0081] refer to Figure 2A , illustrates an electrosurgical device 100 according to the present disclosure. Generally, the device 100 includes a housing 102 having a proximal end 103 and a distal end 105, and a tube 104 having an open distal end 106 and a proximal end 108 coupled to the distal end 105 of the housing 102. The housing 102 includes a right housing 110 and a left housing 112, and also includes a provision for a button 114 and a slider 116. Activation of the slider 116 will expose a blade 118 at the open distal end 106 of the tube 104. Activation of the button 114 will apply electrosurgical energy to the blade 118, and in some embodiments, enable gas to flow through the flow tube 122, as will be described in detail below.

[0082] In addition, a transformer 120 is disposed on the proximal end 103 of the housing for coupling a source of radio frequency (RF) energy to the device 100. By providing the transformer 120 in the device 100 (as opposed to locating the transformer in the electrosurgical generator), power for the device 100 is generated from a higher voltage and lower current than would be required when the transformer is located away from the generator, which results in a lower thermalizing effect. In contrast, a transformer further back in the generator generates applicator power at a lower voltage, higher current with a greater thermalizing effect. Thus, by providing the transformer 120 in the device 100, collateral damage to tissue at the surgical site is minimized.

[0083] Figure 2B A cross-sectional view along line AA of the device 102 is shown. A flow tube 122 extending along the longitudinal axis of the device 100 is disposed within the housing 102 and the tube 104. At a distal end 124 of the flow tube 122, a blade 118 is retained within the flow tube 122. A proximal end 126 of the flow tube 122 is coupled to a gas source via a tube connector 128 and a flexible tubing 129. The proximal end 126 of the flow tube 122 is also coupled to an RF energy source via a plug 130, which is coupled to the transformer 120. The flow tube 122 is made of a conductive material, preferably stainless steel, so as to conduct RF energy to the blade 118 when used for plasma application or electrosurgical cutting, as described below. The outer tube 104 is constructed of a non-conductive material, such as Lestran. The slide 116 is coupled to the flow tube 122 via a retaining collar 132. A printed circuit board (PCB) 134 is disposed in the housing 102 and controls the application of RF energy from the transformer 120 via a button 114.

[0084] It should be understood that the slide 116 may be freely movable in a linear direction or may include a mechanism for incremental movement (e.g., ratcheting) to prevent an operator of the device 100 from over-extending the blade 118. By employing a mechanism for incremental movement of the blade 118, the operator will have greater control over the length of the blade 118 that is exposed to avoid damage to tissue at the surgical site.

[0085] An enlarged view of the distal end 106 of the outer tube 104 is also provided. Figure 2B Here, the blade 118 is coupled to the flow tube 122, which is held in place in the outer tube 104 by at least one seal 136. The at least one seal 136 prevents gas from flowing back into the tube 104 and the housing 102. A cylindrical ceramic insert 138 is disposed in the distal end of the outer tube 104 to hold the blade along the longitudinal axis of the device 100 and to provide structural support during mechanical cutting when the blade is exposed outside the distal end of the outer tube 104.

[0086] Now refer to Figure 3A and 3B Describes operational aspects of the device 100, wherein Figure 3A shows an enlarged cross section of the device, and Figure 3B The diagram shows a front view of the device.

[0087] refer to Figure 3A , the flow tube 122 is disposed in the outer tube 104, wherein a cylindrical insulator 140 is disposed around the flow tube 122. The slider 116 is coupled to the insulator 140 and is used to extend and retract the blade 118. At the distal end 106 of the outer tube 104, an annular or ring-shaped seal 136 and a cylindrical ceramic insert 138 are disposed around the flow tube 122. As shown in Figure 3B As can be seen in the figure, the generally planar blade 118 is coupled to the inner circumferential portion of the cylindrical flow tube 122 so that two gas passages 142, 144 are formed on either side of the blade 118. When the gas flows through the flow tube 122 from the proximal end 103 of the housing, the gas will flow past the blade 118 and out the distal end of the outer tube 104.

[0088] When the blade is Figure 3A When in the retracted position shown, the device 102 is suitable for generating plasma. In the retracted position, RF energy is conducted from an electrosurgical generator (not shown) to the tip 146 of the blade 118 via the flow tube 122. An inert gas (such as helium or argon) is then supplied to the flow tube from either the electrosurgical generator or an external gas source. When the inert gas flows through the tip 146 of the blade 118, which maintains a high voltage and a high frequency, a cold plasma beam is generated.

[0089] Reference Figure 4, the blade 118 is advanced via the slider 116 so that the tip 146 extends through the distal end 106 of the outer tube 104. In this state, the blade 118 can be used in two cutting modes: mechanical cutting and electrosurgical cutting. In the mechanical cutting mode, RF or electrosurgical energy is not applied to the flow tube 122 or the blade 118, and therefore, the blade 118 is in an off state. In this mode, the blade 118 can remove tissue via mechanical cutting. After the tissue is removed, the blade 118 can be retracted via the slider 116, and electrosurgical energy and gas can be applied via the button 114 to generate a cold plasma beam for cauterization, disinfection and / or hemostasis of the surgical patient site.

[0090] In the electrosurgical cutting mode, the blade 118 is advanced and used while powered and with an inert gas flow. This configuration is similar to the electrosurgical knife method, where the electrosurgical energy performs the cutting. However, with the addition of the inert gas flow, the incision is virtually eschar-free, with very little collateral damage along the sidewalls of the incision. The cutting speed is significantly faster and the mechanical cutting resistance is less than when the blade is not powered (i.e., mechanical cutting mode). Hemostasis is also affected during this process.

[0091] As described above, an electrosurgical device capable of generating cold plasma, such as a plasma generator and device 100 of approximately 14, can be used in electrosurgery to apply electrosurgical energy to a surgical site (e.g., a patient's tissue) via a generated cold plasma beam. As will be described below, the energy density applied to the surgical site may vary (significantly) based on any one of a variety of factors. However, it is critical that the energy density applied to the surgical site is maintained within a narrow beneficial range to achieve the desired physiological effect at the surgical site. The present disclosure provides a skin condition monitoring device that is configured to sense the energy density applied to the surgical site in real time based on one or more factors. Based on the sensed applied energy density, the applied power level of the cold plasma beam can be adjusted so that the energy density applied to the surgical site is maintained within a beneficial range for achieving the desired physiological effect at the surgical site. In one embodiment, the skin condition monitoring device of the present disclosure is configured to be connected to the distal end of an electrosurgical device capable of generating cold plasma. In other embodiments, the electrosurgical device may include an integrated skin condition monitoring component.

[0092] The deposition of energy to a surgical site, for example by using a cold plasma generating device (such as, but not limited to, the apparatus 14 and 100 described above), can affect a variety of surgical procedures. More specifically, a given minimum energy density (e.g., in joules per unit area) must be applied to the surgical site to achieve the desired physiological effect. However, there may be a threshold energy density above which tissue damaging effects will occur at the surgical site. In some cases, the threshold between a beneficial effect and a damaging effect may be very steep, and a relatively small increase in energy density will cross this threshold. In other words, increasing the applied energy density by only a few percent can make the difference between a therapeutic effect and a damaging effect.

[0093] Several factors affect the energy density applied to the surgical site. These factors include, but are not limited to, the application area, the applied power level of the plasma beam, the ability of the application site to absorb energy, any cooling factors that remove energy from the application site, and residence time. In the case of a cold plasma jet applicator, such as the above-mentioned devices 14 and 100, the flow rate of the carrier gas used as an additional coolant also affects the net applied energy density to the operating site.

[0094] Cold plasma is applied to the application portion from the applicator tip of the cold plasma generating device (e.g., such as via the distal end 106 and flow tube 122 of the device 100). The distance from the applicator tip to the application site can play an important role in the energy density applied. This is especially true for optical-based energy applicators, such as lasers. Here, the applied power density is inversely proportional to the distance of the applicator from the application site, and relatively small changes in the applicator distance can have a significant effect on the applied power density. It should be noted that the term applied power density refers to the instantaneous amount of effective power applied to a given area, expressed in power per unit area (e.g., watts / cm 2 The applied energy density is given in units of watts per square meter. The applied energy density is determined by multiplying the applied power density by the duration for which the power density is applied to a given area. This duration is sometimes referred to as the dwell time. The units of applied energy density are energy per unit area, such as watt-seconds / cm 2 or Joule / cm 2 It should be noted that the term "applied" or "effective" is intended to mean the actual power density or energy density absorbed at the surgical site, and takes into account various mechanisms by which power or energy may be removed, such as cooling by air flow, blood flow, and / or evaporative cooling.

[0095] Many procedures require that the applicator beam (i.e., the cold plasma beam ejected from the applicator tip of the cold plasma generating device) be scanned over a given area of ​​the surgical site. The dwell time is then related to the scanning speed of the applicator tip over the operating site. The faster the scanning speed, the shorter the dwell time, and vice versa. Since the applied energy density is the product of the applied power density and the dwell time, all other factors being equal, the faster the scanning speed, the lower the energy density applied to the surgical site, and so on.

[0096] Of the factors that affect applied energy density, scanning speed is the least easily controlled, particularly when the applicator is scanned by hand, as is the case with the above-described devices 14 and 100. Where the threshold between beneficial and damaging applied energy densities is relatively narrow, relatively small changes in applicator scanning speed can cross the threshold and produce undesirable physiological effects at the surgical site.

[0097] According to an embodiment of the present disclosure, a method and apparatus for real-time monitoring of the energy density applied to a surgical site are provided, so that changes in factors affecting the energy density can be compensated, thereby producing a consistent physiological effect on a given area. For example, the applied power level can be adjusted in response to a variable monitored in real time by the device of the present disclosure at the application site. If the monitored variable indicates that the applied energy density is approaching a predetermined damage threshold, the applied power level of the cold plasma beam generated by the applicator can be reduced proportionally to keep the applied energy density within a predetermined beneficial range. Similarly, if the device of the present disclosure determines that the applied energy density has dropped below a predetermined beneficial level or range, the applied power level of the cold plasma beam generated by the applicator can be increased proportionally to keep the applied energy density within a predetermined beneficial range. In the case of compensating for variable scanning speed, if the device of the present disclosure determines that the applicator is moving too slowly instantaneously, the applied power level will be reduced, and if the device of the present disclosure determines that the applicator is moving too fast, the applied power level will be increased. It should be understood that the device of the present disclosure will be described in more detail below.

[0098] Several variables indicating the applied energy density can potentially be monitored. These include tissue surface temperature, tissue electrical impedance and acoustic properties. However, some of these monitored variables may be disturbed by the energy application process. For example, the process of measuring tissue electrical impedance usually utilizes a test signal whose amplitude is on the order of a few millivolts, while the voltage adopted by the cold plasma jet can be on the order of several kilovolts. Fortunately, this cold plasma jet is electrically pulsed, and the quiet inter-pulse period can be used for electrical impedance measurement. For acoustic monitoring, similar arguments can be made, such as using ultrasonic characteristics, where the inter-pulse period can be used for acoustic measurement. Temperature measurement can be achieved by direct tissue surface contact or by using infrared emission. In the latter case, again, the contribution from energy application must be filtered out or otherwise removed. It should be understood that the skin condition monitoring device of the present disclosure (first shown in FIG. 8) can be configured to use these techniques to monitor any of the above variables to filter out any interference of the electrosurgical applicator to the measurement of the monitored variables.

[0099] For a given applied energy density and tissue properties, a temperature distribution is produced both in the depth of the tissue and laterally across the surface of the tissue and away from the point of application. Figures 5A-5C , showing various applied energy density distributions according to the present disclosure and their relative effects on the heat or temperature diffusion distribution generated on the tissue of the surgical site. Figure 5A In the present invention, a low energy density plasma beam or jet 502 is applied by an applicator (e.g., such as the apparatus 14, 100 described above) to an application point 504 on a patient tissue surface 506. The energy density applied to the tissue surface 506 by the plasma beam 502 produces a tissue heat diffusion profile 508 that spreads radially from the application point 504 away from the application point 504 into the depth of the patient tissue and laterally across the tissue surface 506.

[0100] exist Figure 5B Medium, medium energy density (i.e., above Figure 5A A low energy density (applied in) is applied to the patient's tissue surface 506 and Figure 5C In FIG. 5A , a high energy density (i.e., higher than the medium energy density applied in FIG. B ) is applied to the patient's tissue surface 506. Figures 5A-5C Inspection of the 504 shows that as the energy density applied to the point 504 of the tissue surface 506 increases, the tissue heat diffusion profile 508 spreads both laterally across the tissue surface 506 and in tissue penetration depth away from the point 504. In this manner, by measuring certain characteristics of the heat diffusion profile 508 resulting from the application of the plasma beam 502 to the point 504 of the tissue surface 506, the applied energy density profile can be determined.

[0101] For example, refer to Figure 6, the temperature at a fixed distance B from the application point 504 to a point 501 on the tissue surface 506 that is laterally disposed from point 504 can be measured and used to determine the applied energy density and the depth of penetration of the heat affected zone 509 into the tissue. The measured temperature at point 501 can be used to determine both the energy density at point 504 and the penetration depth C of the heat affected zone 509 through the applied energy density at point 504. In principle, the applied energy density can be calculated based on the measured surface temperature at a given distance away from the application point. However, the values ​​of variables such as thermal conductivity, specific heat, and loss mechanisms including conduction, evaporation, and radiation losses may only be approximately known, and their values ​​may also be temperature dependent. In practice, the relationship between the applied energy density and the surface temperature can be determined experimentally and then stored in a lookup table.

[0102] In certain applications, such as skin resurfacing and wrinkle removal, it is important to limit the depth C of the heat affected zone 509 (ie, the volume of tissue defined by the heat diffusion profile 508). During energy deposition, the underlying vascularization must not be damaged.

[0103] An additional complication in the surface temperature measurement is that the radial symmetry of the temperature distribution 508 may be affected by the scanning motion of the applicator. According to the present disclosure, this effect is Fig. 7A When the tip of the applicator is in direction A (such as Fig. 7A As the energy source 504 (indicated in FIG. 5A ) moves over the patient's tissue surface 506, a trailing "tail" 510 of heat dissipation may form in the temperature distribution 508. The temperature measurement in the heat dissipation tail 510 of the energy application point 504 will include both the contribution from the general radial surface heat diffusion 508 and the contribution from the dissipation of the energy deposition itself.

[0104] According to the present disclosure, one of the variables that affects the applied energy density (the distance from the applicator to the tissue surface) can be controlled by using Fig. 8A , 8B 9 and the support device 700 to control and fix. It should be understood that, as will be described below, the support device 700 can be used as the above-mentioned skin condition monitoring device.

[0105] like Fig. 8A , 8BAs shown in Figures 1 and 9, the support 700 can be coupled to the distal portion 602 of the applicator 600. It should be understood that the applicator 600 can represent any of the above-mentioned devices 14, 100, or any other electrosurgical device capable of applying cold plasma to a surgical site. The applicator 600 includes a handle housing 601 and a distal applicator tip or nozzle 604 extending distally from the housing 601. Although not shown, in one embodiment, a shaft or tube couples the housing 601 to the distal tip 604. The cold plasma generated by the applicator 600 is discharged from a hole 606 (such as a nozzle 604) disposed on the distal end 605 of the tip 604. Figure 8B 604) and is applied to the patient's tissue surface 506. It should be understood that the electrode 608 can be disposed within the interior of the tip 604 to ionize the carrier gas provided to the tip 604, thereby generating a cold plasma beam. In one embodiment, the electrode 608 can be retractable and configured as a flat blade in a manner similar to the blade 118 of the above-described device 100. In other embodiments, the electrode 608 can be configured into other suitable shapes, such as a needle, a ball, a wire, or any other type of electrode without departing from the scope of the present disclosure.

[0106] The support 700 includes an applicator receiving portion 702 disposed toward a proximal end 701 of the support 700 and a base 706 disposed toward a distal end 703 of the support 700. The base 706 is coupled to the applicator receiving portion 702 via one or more supports or posts 704 coupled to an outer circumferential portion of the base 706. Fig. 9 As best shown in , receiving portion 702 is configured to receive distal portion 602 of applicator 600 (e.g., in a channel or slot extending from end 701 to surface 705) such that applicator tip 604 is disposed through a hole in surface 705 of support 700. Distal portion 602 may include a distal portion of housing 601, a distal portion of a shaft or tube coupling housing 601 to tip 604, and / or a portion of tip 604. In one embodiment, support 700 may include a securing device (e.g., a clamp or other securing device disposed on end 701) for securing support 700 to tip 604 and / or distal portion 602 when distal portion 602 of applicator 600 is received by receiving portion 702. In one embodiment, base 706 is configured in an annular or ring-like shape such that base 706 includes hole 708 defined by an outer circumferential portion. As shown in FIG. Figure 8B As best shown in FIG. 7 , when the support 700 is coupled to the distal portion 602 of the applicator 600 , the hole 606 of the tip 604 and the hole 708 of the base 706 are coaxially aligned such that when the plasma exits the hole 606 of the tip 604 , the plasma is directed to the hole 708 .

[0107] like Fig. 8AAs shown, the base 706 is disposed away from the receiving portion 702 via the post 704 so that when the base 706 is in contact with the tissue surface 506, the distal end 605 of the tip 604 is maintained at a fixed predetermined distance D from the base 706 / tissue surface 506. In this way, the effect that the distance D from the distal end 605 of the tip 604 to the tissue surface 506 has on the applied energy density remains constant. When the distance D from the distal end 605 of the tip 604 remains constant, the applied energy density is more easily maintained constant, and one can focus on the remaining factors that affect the applied energy density, as will be described below.

[0108] The support base 706 ( Figure 8B ) provides a convenient location for sensor monitoring of tissue status during energy application. In one embodiment, the base 706 includes one or more embedded sensors for monitoring various characteristics or properties (e.g., temperature) of the tissue surface 506 at the surgical site. When the base 706 is in contact with the tissue surface 506 during electrosurgery, the sensors in the base 706 will also contact the tissue surface 506 to obtain the desired measurement results (e.g., in one embodiment, temperature measurements). For example, Fig. 10A and 10B Each of the diagrams includes a view through the distal end 703 of a mount 700 having various sensor configurations implemented with a base 706 according to the present disclosure. Fig. 10A In FIG. 1 , an annular or ring-shaped sensor 720 (eg, a temperature sensor) is shown embedded in the base 706 and in FIG. 1 . Fig. 10B , one or more discrete or separate sensors 720 (i.e., 720A-D) are shown embedded in the base 706. As will be described in more detail below, each sensor 720 can be coupled to one or more components of the holder 700 and / or the applicator 600 (e.g., a controller or processor), wherein any measurements obtained by the sensor 720 can be provided.

[0109] From a cost and complexity perspective, it would be desirable to use the minimum number of sensors 720 possible to achieve the necessary feedback of applicator power level. However, given the potential impact of the thermal dissipation "tail" 510 of the scanning applicator (e.g. Fig. 7A As shown in Figure 1), a single temperature sensor must be radially symmetric to account for the possibility that the applicator can move in any direction. Fig. 10A As shown, the annular sensor 720 includes a necessary radially symmetrical shape. Fig. 10B, an array of at least two temperature sensors 720 may be utilized. It should be understood that any given temperature sensor 720 must have a low thermal mass so that the sensor 720 can quickly respond to any temperature changes measured on the tissue surface 506 and use these measurements in a feedback loop to adjust the applied power level of the plasma beam 502 in a timely manner.

[0110] like Fig. 10B As shown in the embodiment of FIG. 5 , the use of multiple sensors 720 allows the detection of the applicator motion direction because at least one or more sensors 720 will be located in the downstream heat dissipation "tail" 510 generated by the motion of the applicator 600. The measurements obtained by the (one or more) sensors 720 in the downstream heat dissipation "tail" 510 will have a higher temperature relative to the other measurements obtained by the remaining sensors 720 disposed at the application point 504. In this way, the higher temperature measured by the sensors 720 in the heat dissipation "tail" 510 can be used to determine the direction of the "tail" 510. Once the direction of the "tail" 510 is known, the direction of motion of the applicator 600 can also be determined because it will be in the opposite direction of the "tail" 510. For example, if the temperature sensed by temperature sensor 720A is higher than the temperature sensed by temperature sensors 720B-D, it can be determined that the "tail" 510 is oriented in the direction D away from sensor 720A and along the surface 506, and the motion of the applicator 600 is in the direction E (opposite direction D) along the surface 506.

[0111] For a given power setting, the degree of asymmetry between upstream and downstream temperatures (i.e., Fig. 7A 510) can be used to infer the speed of the applicator. For example, if the applicator is moving relatively slowly, then for a given power setting, the energy density applied will be high, and therefore the time required to dissipate the energy will be longer. As a result, the asymmetry will be greater, resulting in a longer "tail" 510, such as Fig. 7A In contrast, if the applicator 600 moves faster, the applied energy density will be lower and the "tail" 510 will be shorter, as shown. Figure 7B shown.

[0112] Including multiple individual sensors 720 also allows for potential compensation for asymmetric energy application distributions. In the case of the cold plasma jet applicator 600, the applicator electrode 608 may be in the form of a blade (as described above) that is wider than it is thick. This produces an elliptical energy application distribution. For example, referring to Fig.11A, a beam footprint 503 of a plasma beam 502 generated by an applicator 600 including a planar blade-shaped electrode 608 on a tissue surface 506 is shown according to the present disclosure. The applicator 600 is being moved so that the beam 502 is scanning the tissue surface 506 in a direction A. As the beam 502 scans the tissue surface 506, along the path scanned by the beam 502, there are treated tissues 505 that the beam 502 has already scanned and untreated tissues 507 that the beam 502 has not yet passed through, but if the beam footprint 503 continues to move in the same direction, the beam 502 will pass through the untreated tissue 507. Fig.11A As shown, if the applicator 600 scans in the direction A along the minor axis 554 of the ellipse of the beam footprint 503, the energy is scanned over a larger area. In addition, as the beam 502 is scanned over the target tissue (i.e., indicated by the footprint 503), the instantaneous dwell time as seen from a given point on the target tissue will be shorter, as shown in FIG. Fig. 11B 550 is shown. This is due to the fact that in the direction of movement A, the length of the axis aligned with the direction of movement A (i.e., the ellipse minor axis 554) is minimized. The wider path and shorter dwell time resulting from the ellipse minor axis 554 being aligned with the direction of movement A of the applicator 600 combine to reduce the overall applied energy density.

[0113] In contrast, if the applicator 600 is scanned in the direction B along the major axis 556 of the ellipse, as Fig. 11B As shown, the energy is on a narrower path (relative to the path generated when scanning on the minor ellipse axis 554, as shown in Fig.11A As shown in Figure 2, the diffusion Fig.11D As indicated by the graph 552 in FIG. 5 , the instantaneous dwell time in this case is longer due to the fact that in the moving direction B, the length of the axis aligned with the moving direction B (i.e., the ellipse major axis 556) is maximized. The narrower path and longer dwell time resulting from the ellipse major axis 556 aligned with the moving direction B of the applicator 600 result in a higher applied energy density, even in Fig.11A and 11B The applied power level and scanning speed are the same in each case depicted as well.A plurality of sensors 720 included in the base 706 of the support 700 allows the two orientations, or orientations between them, to be detected and the applied power level to be adjusted for a constant applied energy density.

[0114] Consider the example of a beam footprint ellipse with a minor axis of 1 mm and a major axis of 2 mm. The individual sensors will have to be spaced close enough to be able to reliably detect the difference between these two axes. In this example, a sensor spacing of at least 0.5 mm will be sufficient. Scanning along the minor axis will produce temperature rise indications on a greater number of sensors because the beam is wider than scanning along the minor axis. Furthermore, scanning along the minor axis will produce a lower temperature rise distribution (i.e., lower applied energy density) in a greater number of sensors than scanning along the minor axis, while scanning along the minor axis will produce a higher temperature rise distribution in a smaller number of sensors, all other things being equal.

[0115] However, using multiple sensors 720 would require a significant increase in the number of interconnecting wires in the cable coupling the applicator 600 and the power generator unit that provides power to the applicator 600. The cost and complexity of such an arrangement is further increased by the need for termination circuits, one for each sensor 720 in the generator unit, to prevent stray high voltage pickup from the power conductors in the cable.

[0116] In one embodiment, the support 700 and / or the applicator 600 include sensor data sampling, A / D conversion and serialization circuitry for the sensor 720 to address the above-described issues. Thus, for any number of sensors 720 included in the support 700, only one wire is required in the cable connecting the power generator unit to the applicator 600.

[0117] For example, refer to Fig.12 , a circuit 750 according to the present disclosure is shown. It should be understood that some or all of the components of the circuit 750 can be disposed in the support 700, in the applicator 600, or in a combination of the devices 600 and 700. The circuit 750 includes a single-wire interface 752, an analog-to-digital (A / D) converter 754, a controller or processor 756, a multiplexer 758, and one or more sensors 720. The controller 756 is coupled to each of the single-wire interface 752, the A / D converter 754, and the multiplexer 758. The A / D converter 754 is also coupled to the single-wire interface 752 and the multiplexer 758. The multiplexer 758 is also coupled to each of the sensor 720 and the A / D converter 754. The circuit 750 is coupled to an external interface (e.g., an electrosurgical generator, such as the ESU 12) via the single-wire interface 752.

[0118] In use, the output from each sensor 720 is sampled by the multiplexer 758, either sequentially or in some other predetermined arrangement. The output of the multiplexer 758 from a given selected sensor 720 is then digitized by the A / D converter 754 and then sent to the single-wire interface 752, which is configured to serialize the received digitized sensor data. The controller 756 is configured to control each component of the circuit 750 based on instructions stored in the controller 756 or in a memory connected to the controller 756. Since the digitized data associated with the measurement results of the sensor 720 are serialized by the single-wire interface 752, only a single additional conductor connected to the single-wire interface 752 is required in the cable connecting the applicator 600 to the generator unit (e.g., ESU 12), and only a single termination circuit is required in the generator unit. If the circuit 750 is included in the support device 700, communication and circuit power can be established through a pair of electrical contacts between the support 700 and the applicator 600. For example, in one embodiment, electrical contacts may be provided or integrated with receiving portion 702 of holder 700 and configured to mate with corresponding contacts on distal portion 602 of applicator 600. Applicator 600 is then configured to provide power to holder 700 and receive communications (e.g., sensor data) from holder 700 via electrical contacts included in applicator 600 and holder 700. Alternatively, holder circuit 700 may be coupled to a separate power source (e.g., a battery) and communicate directly with the generator unit via RF or optical wireless means.

[0119] It should be understood that the sensor data sampled from the sensor 720 can be provided to a controller or processor of the applicator 600 and / or a controller or processor of a generator unit coupled to the applicator 600. As described above, the measurements from the sensor data can be used by the controller and / or generator unit of the applicator 600 to determine the applied energy density of the plasma beam 502 at the application point 504 on the patient's tissue surface 506. Based on the determined applied energy density, the controller and / or generator unit of the applicator 600 can adjust the power level of the plasma beam 502 (i.e., by adjusting the power applied to the electrode 608) to maintain a predetermined applied energy density.

[0120] As described above, the temperature measurements of the temperature on the tissue surface 506 at the application point 504 obtained from the sensor 720 can be used by the controller of the applicator 600 and / or the generator unit coupled to the applicator 600 to determine the energy density applied to the patient's target tissue in real time. The temperature measurements obtained from the sensor 720 can also be used by the controller to determine the shape (e.g., in some embodiments, an elliptical shape) of the beam footprint 503 by the electrodes 608 of the applicator 600, the direction of movement of the tip 604 of the applicator 600 relative to the tissue surface 506, and the speed of movement of the tip 604 of the applicator 600 relative to the tissue surface 506. The determined temperature on the tissue surface 506 at the application point 504 can be used in conjunction with other known properties of the plasma beam 502 (e.g., applied power level, gas flow rate, fixed distance between the distal tip 604 and the tissue surface 506, etc.) and the target tissue to maintain the applied energy density to the target tissue within a beneficial range to produce a desired physiological effect. There are many physical relationships that can be used to obtain temperature data and ultimately calculate the appropriate power setting for the applicator 600 to maintain the desired physiological effect within a beneficial range. However, this computationally intensive approach will require considerable CPU speed, especially since real-time response is essential. A preferred approach is to store the various temperature data / power setting relationships in a lookup table (e.g., stored in a memory of the applicator 600 or ESU 12) to achieve rapid real-time response. The contents of the lookup table can be predetermined offline by computationally intensive methods, experimental data, or some combination thereof.

[0121] For example, if the controller determines that the currently applied energy density has dropped below the beneficial range or a predetermined value or threshold, the controller is configured to transmit a signal to the generator unit to increase the power applied to the plasma beam 502 until the applied energy density increases to the beneficial range. Alternatively, if the controller determines that the currently applied energy density has exceeded the beneficial range, the controller is configured to transmit a signal to the generator unit to reduce the power applied to the plasma beam 502 until the applied energy density decreases to the beneficial range. In this way, the controller is configured to continuously determine the applied energy density in real time, and increase or decrease the applied energy density (by instructing the generator unit to increase or decrease the applied power level of the plasma beam 502) as needed based on the determined applied energy density to keep the applied energy density within the beneficial range. It should be understood that the beneficial range may vary for different procedures and target tissues. The beneficial range for a given procedure and target tissue can be predetermined and stored in the memory of the applicator 600 and / or the generator unit.

[0122] Different methods can be used to monitor the effect of energy deposition on the target tissue site using the cold plasma jet applicator 600 by measuring changes in tissue impedance through the conductive properties of the cold plasma beam 502 itself. This requires measuring the plasma beam voltage and current. Ideally, these measurements can be conveniently performed in the generator unit 12. However, depending on the location and positioning of the cables in the surrounding environment, variable losses in the cable wires 30 and 32 may require plasma beam voltage and current measurements to be performed directly in the applicator 600.

[0123] This principle is Fig.13A and 13B It is shown in Fig.13A shows how the total impedance measured at the applicator tip 604 is the sum of the cold plasma beam impedance and the tissue impedance, and Fig. 13B is an equivalent circuit 770. It should be understood that in one embodiment, the beam impedance is measured or sensed at the applicator tip 604 by one or more sensors (e.g., voltage and / or current sensors) disposed in the applicator tip 604. In another embodiment, the beam impedance is measured or sensed by a sensor in an electrosurgical generator (e.g., ESU 12) coupled to the applicator 600 by sampling the current and voltage output by the electrosurgical generator to the applicator 600. In either case, a potential problem with this approach is that the cold plasma beam impedance is very sensitive to the distance between the applicator tip 604 and the surface 506 of the target tissue site. As this distance decreases, the plasma impedance decreases. However, by using the fixed distance support device 700 of the present disclosure, the distance between the applicator 600 and the tissue also remains fixed and is therefore known. For a given set of conditions of applied power level, carrier gas flow rate, and distance between the distal tip 604 of the applicator 600 and the tissue surface 506, the tissue impedance can be calculated by subtracting the known plasma impedance (e.g., by a controller / processor of the applicator 600 or ESU 12) from the total impedance (the sum of plasma and tissue impedance) measured from the applicator tip 604 or ESU 12.

[0124] refer to Fig.14, graphs 902 and 904 are shown in accordance with the present disclosure. Graphs 902 and 904 show typical changes in tissue impedance under electrosurgical conditions using 80 watts (graph 902) and 40 watts (graph 904). As energy is applied to the target tissue site 506, the tissue gradually dries out and its impedance increases. The controller and / or generator unit of the applicator 600 can use this impedance change to modify the applied power level of the beam 502 to maintain a constant physiological effect, particularly while the applicator 600 is being scanned, or to stop further energy application when a desired physiological endpoint is reached in a stationary applicator mode. For example, as the total calculated impedance increases, the applied power decreases.

[0125] In another embodiment of the present disclosure, another method of using a cold plasma beam to measure subtle tissue changes under applied energy is to monitor the phase shift change between the voltage and current of the plasma beam 502. It should be understood that in one embodiment, the voltage and current of the plasma beam 502 are measured or sensed at the applicator tip 604 by one or more sensors (e.g., voltage and / or current sensors) disposed in the applicator tip 604. In another embodiment, the voltage and current of the plasma beam 502 are measured or sensed by sensors in an electrosurgical generator (e.g., ESU 12) coupled to the applicator 600 by sampling the current and voltage output by the electrosurgical generator to the applicator 600. In either case, the phase shift between the voltage and current of the plasma beam 502 is calculated by a controller of the applicator 600 or the electrosurgical generator based on the collected voltage and current measurements.

[0126] The voltage and current phase relationship of plasma beam 502 depends on the equivalent dielectric constant of the target tissue site. The equivalent dielectric constant will change with the degree of dryness and bulk tissue temperature at the application site. Using a comparison with a predetermined desired phase relationship for a desired physiological effect, the measured phase shift can be used as a feedback signal to adjust the applied power (e.g., by a controller and / or generator unit of applicator 600). Untreated tissue will have a combination of resistance and capacitance components that produce a fixed phase shift, and its actual value will depend on the frequency of the plasma beam. A plasma beam with a lower frequency will make the capacitance component dominant, while a plasma beam with a higher frequency will make the resistance component dominant. This is because the capacitive reactance is inversely proportional to the frequency. At higher frequencies, the capacitive reactance becomes smaller. However, as the tissue dries, the capacitive property becomes stronger and stronger. Therefore, for a given plasma beam frequency, as the tissue dries, the phase shift will increase.

[0127] For example, refer to Fig.15, a block diagram of a circuit 800 according to the present disclosure is shown. The circuit 800 includes a current measurement module 802, a phase comparator 804, a voltage measurement module 806, a plasma beam impedance module 808, a tissue impedance module 810, a data acquisition and analysis module or processor 812, a feedback control module 816, and a cold plasma power supply 814. It should be understood that some or all of the components of the circuit 800 can be provided in the applicator 600, the device 700, and / or a generator unit (e.g., ESU 12) coupled to the applicator 600.

[0128] Power is provided to the applicator 600 via a cold plasma power supply 814 (e.g., an electrosurgical generator) to generate the plasma beam 502. A current measurement module 802 (e.g., a current sensor) and a voltage measurement module (e.g., a voltage sensor) 806 are configured to measure the current and voltage of the plasma beam 502 applied to the tissue site 506, respectively, based on the power provided to the applicator 600 by the cold plasma power supply 814. The voltage and current measurements of the modules 806, 802 are then provided to a phase comparator 804. The phase comparator 804 is configured to determine a phase shift between the voltage and current of the plasma beam 502 and provide the determined phase shift to a data acquisition and analysis module 812. Based on the phase shift data received from the phase comparator 804, the module 812 is configured to determine whether a predetermined phase shift change has occurred between the voltage and current of the plasma beam 502, thereby indicating a change in the applied energy density of the plasma beam 502. If module 812 determines that a predetermined phase shift change has occurred, module 812 provides a signal indicating the phase shift change to feedback controller 816. It should be understood that module 812 can determine the amount by which the power level of plasma beam 502 needs to be changed, that is, the amount by which the power level needs to be increased or decreased to maintain the desired level of applied energy density. The signal provided to feedback control 816 may include this determination of module 812. Based on the signal provided to feedback controller 816, the power provided to applicator 600 by cold plasma power supply 814 can be adjusted to increase or decrease the applied energy density as desired, thereby maintaining the desired physiological effect on the target tissue site. Feedback control module 816 may include a lookup table that converts a specific phase shift value into a change in the applied power level given a specific baseline power setting and gas flow rate. For example, a small phase shift at a low power setting may only require a small adjustment in the applied power, while the same phase shift at a high applied power setting may require a larger adjustment to maintain the desired physiological effect.

[0129] Modules 808 and 810 represent the actual electrical impedance characteristics of the plasma beam and tissue, respectively, and are equivalent to Fig. 13B. Because the phase shift of tissue impedance 810 is measured by plasma beam impedance 808, the total phase shift measured by phase comparator 804 will be the sum of the phase shifts introduced by plasma beam impedance 808 and tissue impedance 810. However, plasma beam 502 is typically operated in a direct discharge, attached beam mode, in which there is a continuous conductive plasma channel between applicator 600 and target tissue site 504. Under such conditions, plasma beam impedance 808 is essentially resistive and introduces little or no additional phase shift itself. In this way, the phase shift measured by phase comparator 804 will be mainly the phase shift of tissue impedance 810. On the other hand, there may be a situation where plasma beam 502 does not operate in direct contact mode and will exhibit both resistive and capacitive components. In addition to the tissue impedance 810 phase shift, this will also introduce a phase shift from plasma beam impedance 808. The phase shift introduced by plasma beam impedance 808 in non-contact mode can be determined experimentally, then stored and subtracted from the measurement provided by phase comparator 804 by data acquisition and analysis 812. The additional phase shift introduced by the non-contact plasma beam remains fixed for a given set of operating conditions (such as power level, gas flow rate, and distance from the applicator to the tissue surface). If these conditions remain fixed, the additional phase shift of the plasma beam can be considered as a fixed offset of the variable phase shift of the drying tissue.

[0130] In another embodiment, electrical tissue impedance may be measured by direct contact electrodes or impedance sensors. Fig.16 An array of electrodes 920 (e.g., electrodes A, B, C, D, E, F, G, H) is shown that can be placed or disposed on a base 906 of a support 900 and that will be in direct contact with the skin. It should be understood that the support 900 is configured in the same manner as the support 700 (e.g., including a receiving portion, a post, and a base). In addition, Fig.16 The typical plasma beam footprint 903 and the associated trajectory of treated tissue 905 as the device scans to the right (as indicated by arrow F) are included. The tissue electrical impedance is determined by selecting a particular pair of electrodes 920. For example, by selecting Fig.16Electrodes A and E in the beam path can also detect the electrical impedance directly below the beam footprint 903, in addition to other tissue along the path. Selecting electrodes C and G will detect both the tissue below the beam footprint 903 plus the treated tissue trajectory 905. Electrode combinations B and C, C and D, or B and D can detect untreated tissue in front of the beam path. Electrodes H and F can only detect treated tissue after the beam has passed through the treated tissue. In this way, the direction and orientation of the applicator can be determined by a controller in the applicator or electrosurgical generator that communicates with electrodes 920. The speed of the applicator can also be derived by the controller using a predetermined relationship between the change in tissue electrical impedance and the applied energy density (e.g., by experiment, by calculation, or both). Since the applied energy density depends on the applied power level and dwell time, and therefore on the applicator speed, knowing the change in electrical impedance and the applied power level, the applicator speed can be, for example, determined by a controller or measurement system 950 (e.g., Fig.17 The controller in the applicator 600 or ESU 12 uses the electrical impedance variation between treated and untreated tissue to correlate it to physiologically beneficial, insufficient, or damaging effects and provides a feedback signal to correct the applied power level to remain within the beneficial effect range.

[0131] Fig.17 A block diagram of a tissue electrical impedance measurement system 950 is shown. A multiplexer 958 selects a pair of electrodes in a skin sensor array, such as electrodes from an electrode array 920. A detection signal from an excitation oscillator 960 is applied to the selected electrode pair through the multiplexer 958, while both current and voltage measurements are performed on the selected electrode pair via a current measurement module 962 and a voltage measurement module 964, respectively. The detection signal is typically on the order of hundreds of millivolts, and the frequency range may be from a few kHz to a few MHZ. The specific excitation voltage amplitude and frequency are selected by a controller 956 and may be adjusted to optimize the probe signal under varying conditions. For example, dry skin will require a higher amplitude, higher frequency probe signal, as will highly dry tissue. If a saline solution is applied to the skin, a lower amplitude, lower frequency will be preferred.

[0132] The voltage and current measurements are digitized by the data acquisition module 966 and fed to the controller 956. The controller 956 calculates tissue impedance as a ratio of voltage to current. By recording the relative timing of the peak voltage and / or the zero crossing of the voltage and current measurements, the controller 956 can determine the phase shift between the two measurements. Using the predetermined relationship between the impedance change and / or phase shift and the physiological effect, the controller 956 generates a feedback signal that is used to adjust the power level generated by the generator and applied to the applicator electrode. For example, if the impedance change determined by the controller 956 is too small, indicating insufficient physiological effect, the controller 956 sends a feedback signal to the generator to increase the power level applied to the applicator 600. If the impedance change determined by the controller 956 is too large, indicating a physiological damaging effect, the controller 956 sends a feedback signal to the generator to reduce the power level applied to the applicator 600. It should be understood that some or all of the components of the circuit 950 may be disposed in the applicator 600, the device 700, and / or a generator unit (eg, the ESU 12) coupled to the applicator 600.

[0133] Acoustic impedance is another form of measurement that can be used to assess the extent of the physiological effects of plasma energy applied to tissue. It causes tissue contraction, which results in increased tissue density, acoustic impedance, and speed of sound propagation. The last parameter, the speed of sound propagation in tissue, is the easiest to measure and is used as a proxy for the extent of the physiological effects.

[0134] Fig.18 A holder device 1000 is illustrated, which includes an arrangement of acoustic transducers 1020 disposed about a base 1006 of the holder 1000, wherein the acoustic transducers 1020 are in direct contact with a tissue surface when the base 1006 of the holder 1000 is in contact with the tissue surface. It should be understood that the holder 1000 is configured in a similar manner to the holder 700 described above (e.g., including a receiving portion, a post, and a base). Fig.18 Also shown is a representative plasma beam footprint 1003 and the associated trajectory of treated tissue 1005 as the applicator scans over the tissue surface (e.g., in the direction of beam motion as shown by arrow G). Electrical pulses or oscillations are applied to a given transducer 1020, causing it to emit acoustic emissions. The acoustic emissions are then received by a second selected transducer 1020, which converts the acoustic emissions back into electrical signals and is then amplified. Knowing the distance between these transducers and the time-of-flight of the acoustic emissions between them, the speed of sound along the path can be calculated by a controller in the applicator 600 or ESU 12. By selecting various transmitter and receiver transducer combinations, different paths through the tissue between them can be acoustically characterized. For example, by selecting Fig.18Transducers A and E in the present invention can characterize the acoustic impedance directly below the beam footprint 1003, in addition to other tissues along the path. Selecting transducers C and G will characterize both the tissue below the beam footprint 1003 plus the treated tissue trajectory 1005. Transducer combinations B and C, C and D, or B and D can characterize the untreated tissue in front of the beam path. Transducers H and F can only detect the treated tissue after the beam has passed through the treated tissue. Similar to the above-mentioned electrical impedance method, in the current acoustic transducer method, the direction and orientation of the applicator can be determined by the controller using the acoustic impedance data collected via the acoustic transducer 1020. The speed of the applicator can also be derived by the controller using a predetermined relationship between the change in tissue acoustic impedance and the applied energy density (e.g., by experiment, by calculation, or both). Since the applied energy density depends on the applied power level and dwell time, and therefore on the applicator speed, knowing the change in acoustic impedance and the applied power level, the applicator speed can be determined. The change in acoustic impedance between treated and untreated tissue is used by the controller to correlate physiologically beneficial, insufficient, or damaging effects and to provide a feedback signal to the generator or ESU 12 to correct the applied power level to keep it within the beneficial effect range.

[0135] In addition to the time-of-flight acoustic properties, the differential acoustic absorption along various acoustic transducer pairs can be used by the controller to assess the physiological state of the tissue along the path. Depending on the extent of the treatment, the treated tissue may have different acoustic absorption properties than the untreated tissue. The acoustic signal sent along a path with higher acoustic absorption will appear weaker at the receiving transducer than the signal sent along a path with lower acoustic absorption. The controller can then use the different degrees of attenuation of this acoustic signal to determine the physiological state of the treated tissue relative to the untreated tissue and generate a feedback signal provided to the ESU 12 to adjust the power level applied by the generator to the applicator 600.

[0136] According to this disclosure, Fig.19 A block diagram of an acoustic impedance measurement system 1050 for use with the mount 1000 is shown in FIG. Under the direction of the controller 1056, a multiplexer 1058 selects a given transmitter and receiver transducer pair from the transducer array 1020, e.g., transducers AH (e.g., Fig.181060 to send a signal to the selected transmitter transducer in the pair, while also starting the time-of-flight measurement module 1062, thereby essentially starting a timer. When the selected receiver transducer in the pair picks up an acoustic emission, the signal is amplified by the receiver amplifier 1064 and then used to stop the time-of-flight timer. The time-of-flight value is then sent to the controller 1056 for use in the time-of-flight measurement module 1062, which then uses a previously determined relationship (e.g., stored in a lookup table) to generate a feedback signal 1066 that is provided to the generator or ESU 12 for the generator to adjust the applied power level (if necessary). It should be understood that some or all of the components of the circuit 1050 can be provided in the applicator 600, the device 700, and / or a generator unit (e.g., ESU 12) coupled to the applicator 600.

[0137] According to this disclosure, Fig. 20 A block diagram of a system 1150 for use with the mount device 1000 to measure differential acoustic absorption is shown in FIG. Under the direction of the controller 1156, the multiplexer 1158 selects a given pair of transmitter and receiver transducers from the transducer array 1120. The controller 1156 then activates the transmit oscillator 1160 to send a signal to the selected transmitter transducer of the pair of transmitter transducers. The selected receiver transducer of the pair has its output amplified by the receiver amplifier 1164, which is then digitized by the A / D converter 1162 and sent to the controller 1156. The controller 1156 selects various transducer pairs to characterize the acoustic absorption of the path between the selected transducer pairs by comparing the amplitude (i.e., intensity) of the received acoustic signal along the path. Based on the different acoustic absorption along the treated and untreated tissue paths, the controller 1156 generates and provides a feedback signal 1166 to the generator or ESU 12 to adjust the applied power level generated by the generator. It should be understood that some or all of the components of the circuit 1150 may be disposed in the applicator 600, the device 700, and / or a generator unit (eg, the ESU 12) coupled to the applicator 600.

[0138] As will be described in more detail below, in other embodiments of the present disclosure, an applicator having an emission collector (e.g., an acoustic tube, an optical fiber, etc.) configured to collect emissions associated with the generated plasma beam and / or the tissue surface (e.g., acoustic emissions, a spectrum, etc.) can be provided. The collected emissions are used by a controller or processor (e.g., disposed in the applicator or an electrosurgical unit coupled to the applicator) to output a feedback signal to the electrosurgical generator to adjust the applied power level of the plasma beam based on the collected emissions.

[0139] For example, in a slightly different approach, the acoustic emissions of the plasma beam itself can be used to assess the physiological state of tissue under the plasma beam, and the frequencies of these acoustic emissions can be used to generate a feedback signal to adjust the applied power level of the generator, and thereby adjust the applied power level of the plasma beam.

[0140] It has been observed that under various conditions of plasma beam power settings, gas flow rates, and the distance of the applicator tip from the application surface, the plasma beam produces acoustic emissions. Under certain conditions, this acoustic emission is audible. In addition, as the distance from the applicator tip to the application surface decreases, the acoustic emission frequency increases. If the applicator distance, power settings, and gas flow rates remain unchanged, the addition of vaporized water and other vaporized tissue components from the tissue being treated will change the frequency of the plasma acoustic emission. This frequency change can be used to monitor the physiological state of the tissue being treated, and can also be used to generate a feedback signal generated by a controller to adjust the power settings of the generator to maintain a beneficial physiological effect.

[0141] Plasma beam acoustic emission can be caused by the flow resistance effect generated by plasma discharge. It has been observed that when only gas flows and no plasma exists, the back pressure of the plasma applicator is low. When the plasma beam is activated, the back pressure can increase by several percent, depending on the power setting. The higher the plasma power setting, the greater the back pressure. The gas packet flowing out of the applicator nozzle can be trapped in the center of the plasma beam due to this back pressure effect, especially close to the target application surface. Usually, the gas flowing out of the applicator nozzle only briefly interacts with the plasma beam before flowing away from the application site. During this elapsed time between the nozzle and the target surface, the gas flowing in the plasma beam only briefly experiences plasma heating. However, if some gas is trapped by plasma confinement, it will continue to heat and expand until the gas expansion pressure equals or exceeds the plasma confinement back pressure. At this point, the trapped gas is discharged through the plasma confinement wall, and acoustic emission is generated in the process. After this back pressure is released, the process can be restarted with a new gas packet, thereby experiencing the same confinement, pressure accumulation and exhaust cycle. This process is called a relaxation oscillator. This repeated cycle periodicity produces a plasma acoustic emission frequency that depends on the strength of the plasma confinement (i.e., the applied power setting) and the gas flow rate (i.e., the trapped gas packet expansion rate). Reducing the distance from the applicator nozzle to the target surface also reduces the plasma beam impedance, thereby heating the trapped gas faster and thereby also increasing the plasma acoustic emission frequency. However, if the applicator distance, the applied power setting, and the gas flow rate remain constant, the plasma acoustic emission frequency is constant due to the relaxation oscillation process of a fixed period.

[0142] If an additional gas source is added to the trapped gas package, the expansion rate increases (i.e., more gas expands), the relaxation period decreases, and therefore the plasma acoustic emission frequency increases. When the plasma beam interacts with the tissue surface, volatile components of the tissue are released, including water vapor, vaporized tissue components, etc. These volatile components serve as an additional gas source to the trapped gas package and cause the plasma acoustic emission frequency to increase. The degree of frequency increase is proportional to the rate of introduction of the volatile components. In this way, changes in the plasma acoustic emission frequency can be used by the controller as an indicator of physiological effects, and are used by the controller to derive feedback signals to adjust the applied power setting of the generator to maintain the beneficial effects.

[0143] Fig.21 An arrangement 1200 is shown in which plasma acoustic emissions can be monitored and used to derive feedback control signals in accordance with the present disclosure. Fig.21 In the arrangement, an applicator 1206 including a nozzle or distal tip 1201, an acoustic transducer 1202, and an acoustic tube 1204 is provided. The acoustic transducer 1202 is configured to convert the plasma acoustic emission frequency of the acoustic emission received via the acoustic tube 1204 into an electrical signal and produce a relatively low level of electrical output, typically on the order of millivolts. In order to minimize interference from the radiated emission of the plasma beam, which is typically operated at a voltage of several hundred to several thousand volts, the non-conductive acoustic tube 1204 connected to the applicator 1206 is used to transmit the plasma acoustic emission from the plasma beam 1208 to the remotely located (i.e., far away from the plasma beam 1208) acoustic transducer 1202. The acoustic tube 1204 and the transducer 1202 may be disposed on and / or integrated with the external portion of the housing, wherein the proximal end of the acoustic tube 1204 has an open end for receiving the acoustic emission, and the distal end of the acoustic tube is coupled to the acoustic transducer 1002. The transducer 1202 may be powered by the applicator 1206 or an independent power source (e.g., a battery, an external power source, etc.). The output from the acoustic transducer 1202 is amplified (e.g., by an amplifier) ​​and digitized (e.g., by an A / D converter), and then used by a controller to generate a feedback signal that is provided to the generator. The amplifier, A / D converter, and controller may be co-located with the acoustic transducer 1202, thereby minimizing the number of additional wires that need to be added to the cable connecting the applicator 1206 to the generator unit.

[0144] In another embodiment, the light emission spectrum from the plasma beam can be used by a controller to generate a feedback signal, which adjusts the applied power level of the generator, and thereby adjusts the applied power level of the plasma beam, so that the physiological effect is kept within a beneficial range. As the plasma beam interacts with the target tissue, and the volatile tissue components are released, some volatile tissue components will interact with the plasma beam and be ionized. When electrons are compounded with these ions, a characteristic spectrum will be generated. In some cases, the presence of only a given spectral component will be sufficient to serve as a signal that the applied energy density is too high. In other cases, the intensity of the emission spectrum derived from the volatile tissue component can be used to derive a feedback signal, to control the applied power level of the generator. For example, if these emission spectra are too weak, the applied power level will increase, and vice versa.

[0145] It is important to choose the selected emission lines so that they will not be confused with emission lines of a carrier gas such as helium or argon, or with emission lines produced by the interaction of the plasma beam with ambient air. These include oxygen species, nitrogen species, oxygen-nitrogen species, hydroxyl radicals, etc.

[0146] Fig. 22 The device 1300 including an applicator 1306 having an applicator nozzle tip 1302 and an optical fiber 1304 according to the present disclosure is illustrated. The optical fiber 1304 includes a tip or end 1307 for collecting an emission spectrum from near the applicator nozzle tip 1302 and providing the emission spectrum to an optical signal processor 1305 in the applicator 1306 or a generator or ESU 12 connected to the applicator 1306. Due to the turbulent effect of the gas flow around the plasma beam 1308, the specific position of the optical fiber tip 1307 of the optical fiber 1304 around the periphery of the nozzle 1302 is not important, because the light emission spectrum originating from the tissue tends to be uniformly distributed in the plasma beam coverage area. However, it is important to make the optical fiber tip 1307 of the optical fiber 1304 close to the outlet of the applicator nozzle 1302 to maximize the light gathering ability of the tip 1307 of the optical fiber 1304. Fig. 22 The optical fiber 1304 in FIG. 1 is shown to be located outside the applicator 1306 (e.g., outside the housing or handle of the applicator 1306), but in some embodiments, the optical fiber 1304 is integrated into the applicator assembly. Because the optical fiber 1304 is non-conductive, it will not interact with the plasma beam or any high voltage components present in the applicator 1306, and will not be subject to stray electrical pickup interference. In one embodiment, the optical fiber 1304 extends from the applicator 1306 to the generator unit and can be embedded in the cable that supplies power and airflow from the generator unit to the applicator 1306.

[0147] In one embodiment, the optical fiber 1304 terminates in a generator unit having an optical interface 1400, such as Fig.23 In one embodiment, the optical interface 1400 obtains an optical signal including a spectrum from the optical fiber 1304 and passes it through a beam splitter 1402, which splits it into two paths 1404 and 1406. One path 1404 is used as a reference signal. The bandpass filter 1408 filters the optical signal received from the beam splitter 1402 and selects at least one emission line or component associated with the carrier gas to be transmitted to the optical detector 1410, wherein Fig.23 Helium is used as an example. The optical detector 1410 then converts the optical reference signal (including the filtered signal with the selected emission line of the carrier gas) into an electrical reference signal. Another optical path 1406 from the beam splitter 1402 passes through a second bandpass filter 1412, which is selected to monitor at least one emission component originating from the tissue and transmits it to the optical detector 1414. The second optical detector 1414 in the path 1406 converts the optical signal (including the filtered signal with the emission line or component originating from the tissue) into an electrical signal. Each electrical signal generated by the detector 1410 is used by a controller or processor (e.g., such as processor 1305) of the interface 1400 to generate a feedback signal to adjust the applied power level. In some cases, the variability of the plasma beam may cause the variability of the emission spectrum originating from the tissue, and may be confused with the changes in the physiological response to the plasma beam. By simultaneously monitoring the carrier gas emission intensity and the emission intensity originating from the tissue, the changes in the plasma beam can be compensated by a controller or processor (such as, processor 1305) in the optical interface 1400.

[0148] In cases where the simple presence of tissue-derived emission lines is sufficient to reduce the applied power level, the beam splitter 1402, reference bandpass filter 1408 and associated photodetector 1410 may be omitted. Only the tissue-derived emission bandpass filter 1412 and its photodetector 1414 are required.

[0149] Fig.23 Not shown are an A / D converter for digitizing the electrical output of the light detector, and a controller or processor that generates a feedback signal based on the compensated intensity of the light emission from the tissue to adjust the applied power level of the generator. The controller or processor may be processor 1305, which may be disposed in or on applicator 1300 or in the generator.

[0150] It should be understood that although the optical interface 1400 is described as being disposed in an electrosurgical generator, in other embodiments, some or all of the components of the optical interface 1400 may be disposed in the applicator 1300 or a device coupled to the applicator 1300 .

[0151] Fig.24A and Fig. 24B An example of light emission from tissue is shown in . A plasma beam using helium flowing at a rate of 4 liters per minute was scanned over the tissue surface at a constant rate of 4 mm per second, with the applicator nozzle tip placed 5 mm above the test tissue (chicken) and set to an applied power level of 20 watts. Fig.24A The observed partial light emission spectrum is shown in Figure 1, which indicates only the strong emission line of helium, centered at approximately 587.5 nanometers. When the applicator scanning speed is reduced to 1 mm per second, the applied energy density increases by a factor of 4, Fig. 24B New tissue-derived emission spectral features are shown to appear. These new features are the so-called sodium "D" lines at approximately 589 and 589.6 nanometers, respectively. If the applicator scan speed is restored to a rate of 4 mm per second, thereby reducing the applied energy density to its previous value, these new features disappear. Using the sodium "D" lines as the light emission spectral features derived from tissue is useful because the presence of sodium chloride (salt) is ubiquitous in most tissue types.

[0152] In the above-described embodiments, noise generated by the plasma discharge may be filtered out at the support 700, applicator 600, or ESU generator 12, either alone or in various combinations. Additionally, as described below, selection of measurement timing periods may provide noise filtering, and may be used alone or in conjunction with filtering at the support 700, applicator 600, or ESU generator 12, again either alone or in various combinations.

[0153] As described above, the energy application process of the applicator 600 can introduce noise into the measurements obtained by the support device 700 and / or the applicator 600 when monitoring the applied energy density during the procedure. When collecting measurements (e.g., temperature on the tissue surface 506, electrical impedance of the beam 502 and the target tissue, etc.) associated with the applied energy density, a controller disposed in the applicator 600 or in a generator unit coupled to the applicator 600 is configured to receive the obtained measurements and filter out noise within the measurements generated by the energy application process. For example, the controller can be configured to use only the electrical impedance or acoustic measurements obtained during the interpulse period of the beam 502, and ignore the measurements obtained outside the interpulse period. It should be understood that the controller may also be configured with other filtering techniques for removing noise from the signal, and such techniques are within the scope of the present disclosure.

[0154] It should be understood that the various features shown and described are interchangeable, ie, features shown in one embodiment may be incorporated in another embodiment.

[0155] While the present disclosure has been shown and described with reference to certain preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made without departing from the spirit and scope of the invention as defined by the following claims.

[0156] Furthermore, while the foregoing text sets forth a detailed description of many embodiments, it should be understood that the legal scope of the invention is defined by the words of the claims set forth at the end of this patent. The detailed description is to be construed as exemplary only and does not describe every possible embodiment because describing every possible embodiment would be impractical, if not impossible. Many alternative embodiments can be implemented using current technology or technology developed after the filing date of this patent that still fall within the scope of the claims.

[0157] It should also be understood that unless the sentence "As used herein, the term "______" is hereby defined to mean ..." or similar sentences are used in this patent, there is no intention to limit the meaning of that term beyond its plain or ordinary meaning, either expressly or by implication, and such terms should not be construed as limited in scope based on any statement made in any part of this patent (except in the language of the claims). To the extent that any term recited in the claims at the end of this patent is cited in this patent in a manner consistent with a single meaning, this is done solely for clarity so as not to confuse the reader, and it is intended that such claim term be limited, by implication or otherwise, to that single meaning.

Claims

1. An electrosurgical device comprising: an applicator including a distal tip, the applicator configured to generate plasma and eject the generated plasma from the distal tip; a mount device comprising an applicator receiving portion, at least one post, and a base, the at least one post coupling the applicator receiving portion to the base, and the applicator receiving portion being configured to receive a distal portion of the applicator such that when the base contacts a tissue surface, the distal tip of the applicator is disposed through an aperture of the applicator receiving portion at a predetermined fixed distance from a tissue surface, wherein the base comprises at least one sensor for monitoring at least one variable associated with the tissue surface when the base contacts the tissue surface, and the sensor is configured to contact the tissue surface when the base contacts the tissue surface; and At least one controller is configured to determine an energy density applied to the tissue surface by the plasma based on the monitored at least one variable and to adjust an applied power level of the plasma based on the determined energy density.

2. An electrosurgical device according to claim 1, wherein The base is configured in an annular shape having an aperture, and the distal tip is oriented such that the plasma is applied to the tissue surface through the aperture of the base.

3. An electrosurgical device according to claim 2, wherein: The base includes an outer circumferential portion defining a bore of the base, and the at least one post is coupled to the outer circumferential portion.

4. The electrosurgical device according to claim 1, wherein: The at least one controller is configured to adjust the applied power level of the plasma such that an applied energy density to the tissue surface remains within a predetermined beneficial range to achieve a desired physiological effect.

5. The electrosurgical device of claim 1 , further comprising at least one controller configured to determine at least one of a direction and / or a speed of movement of the distal tip of the applicator relative to the tissue surface based on the at least one variable.

6. The electrosurgical device according to claim 1, wherein: The at least one sensor is a ring sensor.

7. The electrosurgical device according to claim 1, wherein: The at least one sensor comprises a sensor array.

8. The electrosurgical device of claim 7, further comprising circuitry configured to serialize measurement data received from the sensor array and output the measurement data to the at least one controller via a single wire.

9. The electrosurgical device according to claim 1, wherein: The at least one sensor is a temperature sensor and the at least one variable is the temperature of the tissue surface.

10. The electrosurgical device of claim 1, wherein: The at least one sensor comprises at least first and second contact electrodes.

11. The electrosurgical device of claim 10 , further comprising a circuit including at least one controller configured to apply a probe signal to the first and second contact electrodes and to measure a voltage and a current of the first and second contact electrodes, the at least one controller configured to determine tissue impedance based on the voltage and current measurements of the first and second contact electrodes and to adjust the applied power level of the plasma based on the determined tissue impedance.

12. The electrosurgical device of claim 10 , further comprising at least one controller circuit configured to apply a detection signal to the first and second contact electrodes and measure a voltage and a current of the first and second contact electrodes, the at least one controller configured to determine a phase shift between the voltage and the current of the first and second contact electrodes and to adjust the applied power level of the plasma based on the determined phase shift.

13. The electrosurgical device of claim 1, wherein: The at least one sensor includes at least a first acoustic transducer and a second acoustic transducer, and the electrosurgical device also includes a circuit configured to apply electrical oscillations to the first acoustic transducer so that acoustic emissions are emitted from the first acoustic transducer into the tissue surface and are received by the second acoustic transducer, and the circuit is also configured to determine the acoustic impedance of the tissue surface based on the distance between the first acoustic transducer and the second acoustic transducer and the flight time of the acoustic emissions emitted between the first acoustic transducer and the second acoustic transducer, and adjust the applied power level of the plasma based on the determined acoustic impedance.

14. The electrosurgical device of claim 1, wherein: The at least one sensor includes at least a first acoustic transducer and a second acoustic transducer, and the electrosurgical device also includes a circuit configured to apply electrical oscillations to the first acoustic transducer so that acoustic emissions are emitted from the first acoustic transducer into the tissue surface and received by the second acoustic transducer, and the circuit is further configured to determine acoustic absorption of the tissue surface based on the amplitude of the acoustic signal received by the second acoustic transducer, and adjust the applied power level of the plasma based on the determined acoustic impedance.

15. The electrosurgical device of claim 1, further comprising at least one sensor for determining an electrical impedance of the plasma and at least one controller configured to adjust an applied power level of the plasma based on the determined electrical impedance.

16. The electrosurgical device of claim 1 , further comprising a circuit for determining a phase shift change between a voltage and a current of the plasma and / or the tissue surface, the circuit comprising at least one controller configured to adjust an applied power level of the plasma based on the determined phase shift change.

Images