Electrosurgical instrument calorimeter and method for measuring the electromagnetic power output of an electrosurgical instrument

Abstract

The present invention relates to an electrosurgical instrument calorimeter for measuring the electromagnetic energy output of an electrosurgical instrument powered by a generator, the electrosurgical instrument calorimeter including a calorimeter cell for containing an absorbing material configured to absorb electromagnetic radiation, at least one temperature sensor configured to measure a temperature of the absorbing material, and a support structure configured to hold the electrosurgical instrument in a position such that electromagnetic radiation emitted by the electrosurgical instrument is absorbed by the absorbing material.

Description

[Technical field]

[0001] The present invention relates to an electrosurgical instrument calorimeter for measuring the electromagnetic power output of an electrosurgical instrument powered by a generator.Furthermore, the present invention relates to a method for measuring the electromagnetic power output of an electrosurgical instrument powered by a generator. [Background technology]

[0002] Modern approaches to human surgery include, but are not limited to, the use of microwave power, typically between 10W and 1000W, delivered using an endoscope, laparoscope, or other microwave power source, typified by the Creo Medical Ltd. CROMA™ Generator, often abbreviated to simply "generator", and a surgical instrument, typified by the Creo Medical Ltd. MicroBlate™, often abbreviated to simply "instrument" or "electrosurgical instrument".

[0003] At the surgeon's command, microwave power is delivered by the generator either as continuous wave (CW) or in bursts of short pulses of up to several minutes to affect a clinical outcome at the target site, e.g., cauterization / coagulation or cutting (resection or incision) of tissue. To achieve a consistent surgical effect, it is necessary to know that the amount of power emitted by the instrument complies with its design specifications. While it is possible to dynamically monitor the amount of power delivered by the generator and actually reflected back to the generator by load mismatch or poor connections, etc., there is currently no readily available means of measuring the amount of power emitted at the surgical instrument tip. For example, there may be unknown damage to the electrical coupling of the connecting cable or some other variation. Also, material variations during the manufacture of the instrument may cause the attenuation (loss) of the microwaves built into the instrument to be higher or lower than specified, possibly causing undesired heating of the connecting cable rather than the target tissue. In these cases, the surgical instrument may deliver inconsistent power levels to the target tissue, causing undesired effects for the surgeon. Summary of the Invention [Means for solving the problem]

[0004] Most generally, the present invention provides an electrosurgical instrument calorimeter that can be used to measure the electromagnetic energy output of an electrosurgical instrument powered by a generator. Additionally, the present invention provides a method of measuring the electromagnetic energy output of an electrosurgical instrument using the calorimeter.

[0005] While there is no direct way to detect the power emitted by an instrument during the surgery itself, it is proposed that the microwave surgical instrument calorimeter described herein may be used during manufacturing and verification and validation (V&V) exercises to ensure that the instrument assembly is performing as designed, or is likely to have performed in a post-operative situation.

[0006] While there are many methods available to measure the performance of regular free-space antennas, such as those typically found in commonly used microwave darkroom equipment, the instruments used in microwave electrosurgery rely on instruments that deliver power to an absorbing non-air medium, usually body tissue. Body tissue consists primarily of water and readily absorbs microwave power. This is the principle on which microwave electrosurgery is based. However, total absorption of the emitted power in this lossy medium (water) means that regular free-space antenna pattern measurements do not work. In free space, the instrument tip can present a large impedance mismatch compared to when in tissue, and the emitted power is fundamentally different than when in contact with tissue. Also, in free space, the radiation pattern of the antenna is determined primarily by the far-field pattern, whereas in lossy media, the near-field pattern becomes more significant, especially due to capacitive coupling of power into the medium.

[0007] It is proposed herein to construct a water or other liquid-based calorimeter as a tissue analog to support manufacturing and V&V activities to measure the temperature rise of the liquid when microwave power is applied to an instrument suspended in the liquid for a known duration. By measuring or knowing the duration for which power is delivered to a known mass of liquid and then measuring the temperature rise of the liquid, it is possible to convert this using the specific heat capacity of the liquid to estimate the amount of energy delivered to the liquid, and the average power delivered by the instrument. This facilitates quantitative performance analysis such as, but not limited to: Comparison of simulated performance data with instruments; Improving the instrument by understanding how much power is being lost between the generator and the distal end of the instrument; Batch checks to ensure the reliability of the manufacturing process, Post-operative quality inspection of instruments to measure whether there are any defects while the instruments are in use; Research and development of destructive and non-destructive instruments; General validation and verification, Automated testing of electrosurgical instruments with industry standard and proprietary control protocols, including the Creo Medical Kamaptive™ protocol; Comparative analysis of alternative or competing technologies from other manufacturers; Measurement of devices capable of delivering multiple electromagnetic frequencies, either simultaneously or sequentially; and / or In combination with a heat-sensitive or electromagnetic field-sensitive material around the tip of the instrument to evaluate the amount of power transferred at various points on the surface of the instrument's radiation pattern.

[0008] The different types of calorimeters available on the market are mainly bomb calorimeters and reaction calorimeters. Bomb calorimeters measure the heat content of substances such as food by controlling their combustion and measuring the temperature rise. Reaction calorimeters also measure the power output of a chemical reaction by measuring the temperature change. Neither of these versions of calorimeters are particularly suitable for measuring the power output of electrosurgical instruments. However, electrosurgical instrument calorimeters, which are specially designed for instruments of various types and sizes, take into account the heat absorption by the instrument itself and can be controlled remotely (e.g. by network connection) for automatic testing.

[0009] The electrosurgical instrument calorimeter is provided for measuring the electromagnetic energy and / or power output of an electrosurgical instrument powered by a generator. The electrosurgical instrument calorimeter includes a calorimeter cell, at least one temperature sensor, and a support structure. The calorimeter cell is configured to house an absorbing material, which is configured to absorb electromagnetic radiation emitted by the electrosurgical instrument. The at least one temperature sensor is configured to measure a temperature of the absorbing material, in particular a temporal change of the absorbing material. The support structure is configured to hold the electrosurgical instrument in a position such that the electromagnetic radiation emitted by the electrosurgical instrument is absorbed by the absorbing material. In one embodiment, the position ensures that a majority, all, or a substantial portion of the electromagnetic radiation emitted by the electrosurgical instrument is absorbed by the absorbing material, e.g., all electromagnetic radiation emitted by the electrosurgical instrument is completely absorbed by the absorbing material.

[0010] The electromagnetic energy output corresponds to the energy of the electromagnetic radiation emitted by the electrosurgical instrument. The electromagnetic power output is the power of the electromagnetic radiation emitted by the electrosurgical instrument to treat tissue at a target site. The electromagnetic power output is the electromagnetic energy output divided by the duration of emission of the electromagnetic radiation. The electrosurgical instrument calorimeter may be configured to measure the electromagnetic energy output and / or the electromagnetic power output.

[0011] The electromagnetic radiation may be radio frequency radiation, and / or microwave radiation, mm wave radiation, and / or infrared radiation. The energy of the electromagnetic radiation is generated by a generator and transmitted to the electrosurgical instrument by one or more cables, such as, for example, coaxial cables. Thus, the generator is the power source for generating the electromagnetic force, and the electrosurgical instrument emits the electromagnetic force at the target site. The generator, the electrosurgical instrument, and / or the cables may form an electrosurgical device. As discussed above, the electromagnetic force may be used to coagulate or cut tissue.

[0012] The electrosurgical instrument may be a scope device that can be inserted into a body cavity. In particular, the distal end of the electrosurgical instrument may be inserted into a body cavity to treat a target tissue. In this case, the electrosurgical instrument may include an instrument tip where electromagnetic power is emitted or transmitted into the target tissue at the target site to achieve the desired therapeutic effect. Alternatively, the electrosurgical instrument may include a waveguide having an energy output port that is positioned above the tissue to be treated, such as skin tissue. When the electromagnetic radiation exits the energy output port of the waveguide, it impinges on the tissue to be treated to achieve the desired therapeutic effect.

[0013] An electrosurgical instrument calorimeter is a device for absorbing the electromagnetic radiation emitted by an electrosurgical instrument and converting it into heat, whereby a temperature change is induced and measured, allowing the energy and / or power released by the electrosurgical instrument to be calculated.

[0014] In an optional embodiment, the electrosurgical instrument calorimeter includes a calorimeter base, where, further optionally, the calorimeter cell is attached to the calorimeter base.

[0015] The calorimeter base may include a housing and forms a base structure to which other components of the electrosurgical instrument calorimeter are attached. The housing may be provided on an exterior surface of the electrosurgical instrument calorimeter. The calorimeter base and / or housing may be made from a plastic material or metal.

[0016] The calorimeter cell is configured to receive and contain an absorbing material provided to absorb the electromagnetic radiation emitted by the electrosurgical instrument, the heat capacity of the absorbing material must be known and is used to calculate the electromagnetic power output of the electrosurgical instrument.

[0017] The absorbing material may be or may include a liquid, a powder of solid particles (e.g., granular material), a solid, a gas, and / or a plasma. A liquid may be a preferred embodiment of the absorbing material, as it has good absorption characteristics in the frequency range typically emitted by electrosurgical instruments, and a heat capacity that is beneficial for calorimeter measurements. In the following, for ease of understanding, references to "liquid" will be understood as generally referring to the absorbing material, where applicable.

[0018] For operation at microwave frequencies, the type of liquid may be water of suitable purity. The choice of liquid is not limited to any one type, but should be of a type that is similar to the impedance of the tissue in which the instrument is typically used. If an instrument that delivers infrared energy is used, it may be appropriate to have the cell container filled with a suitable infrared absorbing material rather than pure water, which allows a high degree of penetration of infrared light. Similarly, if the instrument needs to deliver low frequency RF power of around 400 kHz, it may be appropriate to use a conductive saline solution.

[0019] The calorimeter cell may be permanently or releasably fixed to the calorimeter base. For example, the calorimeter cell is disposed within a hole or socket in the housing. The calorimeter cell has an opening through which liquid can be inserted into the calorimeter cell. The overall configuration of the calorimeter cell may be that of a beaker or cup.

[0020] The calorimeter cell may be thermally insulated to reduce heat loss, since heat loss adversely affects the measurement of the electromagnetic power output of the electrosurgical instrument, i.e., the thermal insulation of the calorimeter cell is provided such that the temperature change induced by the absorption of the electromagnetic radiation emitted by the electrosurgical instrument is not significantly distorted by heat loss in the calorimeter cell.

[0021] One or more temperature sensors are provided to measure the temperature of the liquid. The temperature sensor may be in contact with the liquid. A variety of different types of temperature sensors may be used, for example a thermistor or other thermal transducer. The temperature sensor may be configured to continuously measure the temperature of the liquid.

[0022] The support structure is configured to hold and / or support the electrosurgical instrument in a position such that the electromagnetic radiation emitted by the electrosurgical instrument is absorbed by the liquid in the calorimeter cell. Optionally, the electromagnetic radiation emitted by the electrosurgical instrument is completely or nearly completely absorbed by the liquid. For this purpose, the support structure may be configured to releasably hold and / or support the electrosurgical instrument. This means that during the measurement, the electrosurgical instrument is attached to the support structure in a position where the part of the electrosurgical instrument that emits the electromagnetic radiation is positioned in or directly above the liquid. For example, the support structure holds the electrosurgical instrument in such a way that the instrument tip is fully inserted in the liquid. If the electrosurgical instrument includes a waveguide, the energy output port is positioned by the support structure near or in contact with the liquid such that substantially all the electromagnetic radiation emitted at the energy output port impinges on the liquid. The energy output port may be an opening in the waveguide. This waveguide opening may be covered with a cover whose material is transparent to the electromagnetic radiation propagating in the waveguide.

[0023] In an optional embodiment, the calorimeter cell includes a cell housing that is fixedly or permanently attached to the calorimeter base, an attachment configured to be releasably attached to the cell housing, and a cell container configured to receive a liquid and disposed within the cell housing.

[0024] The cell housing, the attachment and the cell container may be concentric with one another so that they can be inserted into one another. In general, the components of the calorimeter cell may be concentric with one another so that they can be inserted coaxially into one another.

[0025] The cell housing serves as a receptacle for holding the attachment. The cell housing may be a blind hole or socket in the housing and may be fluid tight. The cell housing may include attachment means for releasably attaching the attachment to the cell housing. The attachment may also include corresponding attachment means that engage with the attachment means of the cell housing. The cell housing may protrude from a surface of the housing or be flush with the housing.

[0026] The attachment may be permanently fixed to the cell housing such that the attachment and the cell housing form a unitary component. However, the cell housing may be detachable from the attachment. The attachment, including the cell container, may be inserted into the cell housing.

[0027] The attachment and / or the cell container may be formed as a receptacle, beaker or cup, and the cell container is inserted into the attachment such that the free openings of both the attachment and the cell container form a common outer surface. Optionally, the cell container and the attachment define a gap between them, and the connection area between the cell container and the attachment is small to reduce heat transfer through the connection area. For example, the cell container has at its opening an outer collar that engages with an inner collar of the attachment. The inner and outer collars can extend around the entire periphery and form the only connection between the attachment and the cell container. Alternatively, the inner and outer collars extend only over one or more sections along the periphery. For example, the inner and outer collars include two connection means arranged opposite each other.

[0028] The cell container may be permanently installed inside the top of the attachment and holds a known, fixed mass of liquid that is heated by the electrosurgical instrument. The cell container may be low mass to reduce the amount of thermal energy absorbed from the liquid. It may also be waterproof, insulating the liquid and reducing the amount of thermal energy dissipated to the surroundings by radiation. A vacuum flask configuration may be used as well, but a mechanically thin plastic insulating material is preferred for durability, low thermal mass, and rigidity. The attachment and / or cell container may have a reflective inner surface to contain the electromagnetic and / or thermal radiation emitted by the electrosurgical instrument within the calorimeter cell.

[0029] The cell housing and / or attachments may be made from metal and / or lightweight plastic materials.

[0030] In an optional embodiment, the cell housing and / or cell vessel provide liquid thermal insulation.

[0031] Thermal insulation may be provided, for example, by applying a vacuum to the space between the attachment and the cell container, as in the vacuum flask arrangement described above, or alternatively, the space between the cell container and the attachment may be filled with a thermal insulating material.

[0032] A number of different sized cell containers may be provided, each supported by the same attachment. In this way, the size of the cell container may be selected to accommodate a volume of liquid selected for the size and energy discharge of the electrosurgical instrument, and the different sized cell containers may each be inserted into the cell housing by means of an adapter. This simplifies the measurement of various types of electrosurgical instruments.

[0033] In an optional embodiment, at least one temperature sensor is disposed in and / or on the cell container.

[0034] The temperature sensor may be disposed exposed on an inner surface of the cell vessel such that the sensor is in contact with the liquid. Alternatively, the temperature sensor may be supported by the cell vessel such that the temperature sensor is disposed within the liquid. Optionally, two or more temperature sensors are provided distributed within the space defined by the cell vessel. The presence of multiple temperature sensors improves the accuracy of the temperature measurement, since it is possible to detect whether the liquid has a uniform temperature distribution.

[0035] The temperature sensor may be an electrical temperature sensor and may include a wire for providing an electrical connection to the temperature sensor. The wire may extend into the space defined by the cell container and the attachment. For example, the temperature sensor may be disposed within a wall of the cell container such that one side of the temperature sensor is in contact with the liquid and another side of the temperature sensor is connected to the wire and faces the space defined by the cell container and the attachment.

[0036] In an optional embodiment, the calorimeter cell includes a first electrical connector attached to the cell housing and a second electrical connector attached to the attachment and in electrical communication with the at least one temperature sensor, and optionally, insertion of the attachment into the cell housing connects the second electrical connector of the first electrical connector.

[0037] The first electrical connector may be a socket and the second electrical connector may be a plug, or vice versa. The first electrical connector may be disposed in a bottom surface of the cell housing and the second electrical connector may also be disposed in a bottom surface of the attachment. When the attachment is inserted into the cell housing, the second electrical connector is connected to or inserted into the first electrical connector. Optionally, the first electrical connector and the second electrical connector provide a mechanical connection between the cell housing and the attachment, optionally also the only mechanical connection between the cell housing and the attachment.

[0038] A wire may be connected to the first electrical connector to provide an electrical connection between the first electrical connector and a controller, described below. The second electrical connector may be electrically connected to a temperature sensor via one or more wires.

[0039] In an optional embodiment, the calorimeter cell further includes a lid for closing the calorimeter cell, and optionally the lid includes a passage for inserting an electrosurgical instrument into the liquid.

[0040] The lid may be configured to close only the opening of the cell container or the cell container and attachment. For example, the lid may be placed over the cell container or a combination of the cell container and attachment. Preferably, the lid has a base portion and an outer wall, and in the closed position the outer wall surrounds the cell container and / or the attachment and the base portion rests on the cell container and / or the attachment. In this case, the outer wall may (further) rest on the housing and / or the cell housing.

[0041] Optionally, the lid is made of a material with low heat capacity and / or includes a reflective surface. Additionally, the lid may be hollow to enhance the thermal insulation effect. These aspects help to reduce the loss of heat from the calorimeter cell. At least one temperature sensor or several temperature sensors may be supported by the lid, for example, one or more temperature sensors may be directly or indirectly connected to the lid. When the lid is placed on the calorimeter cell, the temperature sensor is immersed in the liquid. This embodiment does not require a first and second electrical connector on the calorimeter cell, since the electronic connection between the at least one temperature sensor and one controller can be routed through the lid. Instead, the first and second electrical connectors may be located on the housing and on the lid. For example, when the lid is placed on the calorimeter cell, the second electrical connector is inserted into the first electrical connector.

[0042] Preferably, the power output of the electrosurgical instrument is measured with a lid on the calorimeter cell. The lid may therefore include a passageway through which the electrosurgical instrument can pass. Optionally, the dimensions of the passageway correspond to the dimensions of the electrosurgical instrument such that there is no or only a small gap between the inner surface of the passageway and the outer surface of the electrosurgical instrument along the way. Multiple lids can be provided, each with a passageway of different size, so that the passageway of each lid can be aligned to the electrosurgical instrument to be measured.

[0043] In an optional embodiment, the electrosurgical calorimeter further comprises a stirrer for stirring the liquid, optionally attached to the lid.

[0044] The stirrer is provided to distribute the heat generated within the liquid evenly. For example, the stirrer distributes the heat generated by the instrument tip around the liquid, preventing the formation of heat pockets. Not only can the stirrer mix the liquid both vertically and horizontally, but it can also be of low mass to reduce the amount of thermal energy it removes from the liquid, and it can be slow enough that the frictional energy imparted to the liquid is insignificant compared to the energy being measured. Through software and calibration, the calorimeter can calibrate and subtract the mechanical frictional energy component imparted to the liquid from the final power and energy results, making the overall measurement more accurate.

[0045] The stirrer may be a stiff helical wire or a small impeller. Other types of stirrers include, but are not limited to, magnetically coupled stirrers or ultrasonic stirrers. In order to minimize the overall thermal mass and frictional kinetic energy imparted to the liquid, a lightweight mechanical stirrer may be used in a preferred embodiment.

[0046] The stirrer may be supported by the lid. Thus, the stirrer may rotate relative to the lid. The lid may include means for rotatably supporting the stirrer, in particular the shaft of the stirrer. The stirrer may be positioned such that it is offset from the passageway but sufficiently close to the passageway so that the stirrer dissipates heat generated by the electrosurgical instrument.

[0047] In an optional embodiment, the electrosurgical instrument calorimeter includes a motor for moving the stirrer.

[0048] The motor may be an electric motor and may generate a rotary motion to rotate the stirrer. The motor may be located in a position such that the heat generated by the motor does not increase the temperature of the liquid. To this end, the motor may be covered with a thermal insulating material.

[0049] In an optional embodiment, the cell housing further includes a motor bracket for supporting the motor.

[0050] The motor bracket may be disposed on an exterior surface of the cell housing. The motor bracket may be any means for mounting an electric motor to the cell housing.

[0051] In an optional embodiment, the lid includes a transmission device for transmitting motion of the motor to the stirrer.

[0052] For example, the transmission device may transmit the rotation of the motor to rotate the stirrer. The transmission device may include one or more gears, cogs, and / or a belt drive for transmitting the rotation of the electric motor to the shaft of the stirrer. Alternatively or additionally, the transmission device includes a magnetic coupling of the motor to the stirrer. The transmission device may magnetically couple the rotation of the motor to the stirrer. The transmission mechanism may be housed within the lid so that the transmission mechanism is not visible from the outside.

[0053] In an optional embodiment, the electrosurgical instrument calorimeter further comprises a stirrer motor configured to move the calorimeter cell to agitate the liquid or powder.

[0054] The stirrer motor may be an electric motor and may be attached to the calorimeter base. In this case, the stirrer motor may rotate and / or move the entire calorimeter cell. In another embodiment, the stirrer motor may be attached to the cell housing and may be configured to rotate the attachment and thus the cell container. In this case, the attachment may be releasably coupled to the stirrer motor. For example, when the attachment is inserted into the cell housing, the attachment is coupled to the stirrer motor, such as to the shaft of the stirrer motor. In another embodiment, a spinning disk is provided that is attached to the shaft of the stirrer motor. The calorimeter cell, attachment, or cell container itself may be (e.g., releasably) attached to the spinning disk. For example, the spinning disk may include one or more fasteners for releasably fastening the calorimeter cell, attachment, or cell container to the spinning disk.

[0055] For example, a stirrer motor can rotate an attachment within a cell housing. However, the stirrer motor may also be configured to shake, stir, or move the calorimeter cell spatially, such as in a back and forth motion. The stirrer motor can generate a linear or rotational force (torque).

[0056] The cell vessel may include stirring means for converting the movement of the cell vessel into a movement of the liquid. The stirring means may include one or more stirring objects that are stationary with respect to the movement of the cell vessel, such that the liquid in the cell vessel is stirred as a result of the movement of the liquid relative to the stirring objects. For example, the stirring objects may be attached to the lid and have the shape of a paddle. The temperature sensor may be located on the stirring objects. Alternatively or additionally, the stirring objects may be attached to the cell vessel. For example, the cell vessel may include a protrusion that protrudes from an inner surface of the cell vessel into the liquid. Further alternatively or additionally, the stirring means is provided by the shape of the cell vessel. For example, the cell vessel may have a rotationally asymmetric shape such that rotation of the cell vessel stirs the liquid. The cell vessel may have a ramp-shaped bottom (e.g. forming a step) that stirs the liquid when the cell vessel is moving.

[0057] The liquid may be agitated by the electrosurgical instrument itself. For this purpose, the electrosurgical instrument is inserted into the liquid and held stationary with respect to the movements of the calorimeter cell, for example by a support structure. In this case, the movements of the calorimeter cell induce a movement of the liquid, which is agitated as it moves relative to the electrosurgical instrument.

[0058] The lid can be attached to the calorimeter base such that the calorimeter cell, particularly the attachments and the cell container, can move (rotate) relative to the lid. The lid may not be in contact with the calorimeter cell, particularly the attachments and the cell container, allowing movement or rotation of the calorimeter cell relative to the lid.

[0059] In an optional embodiment, the support structure is supported by the calorimeter base. Optionally, the entire support structure or portions of the support structure may be permanently fixed to the calorimeter base. Thus, the support structure forms part of the electrosurgical instrument calorimeter. This allows the calorimeter cell to have a fixed relationship between the support structures, simplifying placement of the electrosurgical instrument in or on the liquid. The support structure may be fixed to a housing of the calorimeter base. Alternatively, the support structure may not be fixed to the calorimeter base, or may be releasably fixed to the calorimeter base.

[0060] The support structure may include a robotic arm configured and / or controlled to position and / or support the electrosurgical instrument in or above the liquid in the calorimeter cell.

[0061] In an optional embodiment, an instrument guide clamp is provided to hold the electrosurgical instrument in an upright position.

[0062] An instrument guide clamp is a means for releasably supporting or holding an electrosurgical instrument. The instrument guide clamp may include a clamp or bracket that may be releasably engaged with a portion of the electrosurgical instrument. The instrument guide clamp is provided to maintain the orientation of the electrosurgical instrument and / or to support the electrosurgical instrument during measurements. In particular, the instrument guide clamp of the support structure may be the only mechanical means for holding the electrosurgical instrument in or above the liquid during measurements. Alternatively, while the instrument guide clamp is provided to support the cable or flexible portion of the electrosurgical instrument, the instrument tip may be held by another mechanical means as described below.

[0063] In an optional embodiment, a stand is provided for supporting the instrument guide clamp, optionally the stand being attached to the calorimeter base.

[0064] The stand may be a rod, bar, or pole that projects from the calorimeter base, particularly its housing. The stand may have a vertical orientation. The instrument guide clamp may project horizontally from the stand. The instrument guide clamp may be configured to be releasably secured to the stand. For example, the instrument guide clamp may be attached to the stand at various heights. The stand and the instrument guide clamp may form a boom.

[0065] The instrument guide clamp may include two mounting portions, a first mounting portion for releasably securing an electrosurgical instrument to the instrument guide clamp and a second mounting portion for releasably securing the instrument guide clamp to a stand.

[0066] In an optional embodiment, the electrosurgical instrument calorimeter further comprises a depth gauge mechanism to facilitate repeatable and consistent placement of the instrument tip of the electrosurgical instrument in the liquid.

[0067] The depth gauge mechanism may be used to precisely position the electrosurgical instrument relative to the liquid. Thus, the depth gauge mechanism allows the electrosurgical instrument to be positioned in the same location each time the electrosurgical instrument undergoes a calorimetry measurement. This facilitates comparable measurements of the energy / power output of the electrosurgical instrument. In other words, the depth gauge mechanism facilitates precise positioning of the electrosurgical instrument.

[0068] For example, the depth gauge mechanism allows the electrosurgical instrument to be positioned in such a way that the instrument tip is fully submerged in the liquid while the rest of the electrosurgical instrument is not submerged in the liquid, in other words, the depth gauge mechanism allows the electrosurgical instrument to be positioned such that only the instrument tip is in contact with the liquid.

[0069] In an optional embodiment, the depth gauge mechanism includes a depth gauge clamp that is attachable to the electrosurgical instrument and has an outer diameter that is greater than the inner diameter of the passageway. Optionally, the depth gauge mechanism further includes a depth gauge socket that has a depth that corresponds to the distance between the distal end of the electrosurgical instrument and the top surface of the lid at a repeatable and consistent position of the electrosurgical instrument.

[0070] The depth gauge clamp may be a bracket, cylinder or clamp that can be releasably attached to the electrosurgical instrument. The mechanism for attaching the depth gauge clamp to the electrosurgical instrument may be similar to that of the instrument guide clamp. The depth gauge clamp increases the diameter of the electrosurgical instrument such that the depth gauge clamp abuts the lid when the electrosurgical instrument is inserted into the passageway of the lid.

[0071] The outer diameter and inner diameter may refer to the longest extension in the cross section of the depth gauge clamp and the passageway, respectively. In other words, the outer dimensions of the depth gauge clamp are such that the depth gauge clamp cannot be inserted into the passageway. The depth gauge clamp therefore acts as a stop for the insertion of the electrosurgical instrument into the passageway. Thus, the distance between the distal end of the electrosurgical instrument and the location of the depth gauge clamp attached to the electrosurgical instrument determines how deeply the electrosurgical instrument is inserted into the liquid. In other words, the attachment point of the depth gauge clamp to the electrosurgical instrument determines the insertion depth of the electrosurgical instrument into the liquid.

[0072] The attachment point can be reliably determined by using a depth gauge socket, which may be a blind hole. For this purpose, the distal end of the electrosurgical instrument is inserted into the depth gauge socket until it abuts the bottom surface of the depth gauge socket. The depth gauge clamp is then attached to the electrosurgical instrument in such a way that it abuts the outer surface of the depth gauge socket. That is, the depth of the depth gauge socket (the distance between the bottom surface of the depth gauge socket and the outer surface of the depth gauge socket) corresponds to the distance between the distal end of the electrosurgical instrument and the outer surface of the lid at the exact position of the electrosurgical instrument relative to the liquid.

[0073] Because the instrument tips of different electrosurgical instruments may have different lengths, multiple depth gauge sockets may be provided, with each depth gauge socket indicating the correct positioning of the depth gauge clamp for a particular type of electrosurgical instrument.

[0074] In an optional embodiment, the depth gauge socket is disposed on the calorimeter base. The depth gauge socket may be located within or on the housing of the calorimeter base. Alternatively or additionally, the depth gauge socket may be external to the calorimeter base. For example, multiple depth gauge sockets are provided by drilling various holes in a solid part.

[0075] In an optional embodiment, the electrosurgical instrument calorimeter further comprises a controller configured to calculate an electromagnetic energy output of the electrosurgical instrument based on measurements of the at least one temperature sensor.

[0076] The controller may include one or more microprocessors, one or more memories, and / or additional electrical components for controlling the electrosurgical instrument calorimeter and analyzing the results detected thereby. The controller may be attached to the calorimeter base, and optionally located within the housing of the calorimeter base. However, the controller may also be an external computer connected to the electrosurgical instrument calorimeter.

[0077] The controller may be connected to at least one temperature sensor as described above. Optionally, the electrosurgical instrument calorimeter includes a display and / or a user interface (e.g., one or more buttons, dials, and / or switches) connected to the controller. The controller may control the display and receive input from the user interface. For example, the amount of liquid to be filled into the cell container and the heat capacity of the liquid may be input using the user interface. The display may be used to display the electromagnetic power output of the electrosurgical instrument.

[0078] The user display may be, for example, a 20x4 character alphanumeric or graphical display and may display the device's operating parameters, any measurement results, as well as simple instructions on how to operate the device. The user interface may optionally be incorporated into a touch-sensitive screen depending on aesthetic or operational needs.

[0079] The controller may include microcontrollers and electronic circuitry and controls all aspects of the operation of the calorimeter through software, including but not limited to setting operating parameters, timing power delivery and sequencing temperature measurements, acting on user interface commands, acting on and generating control events to and from the control connector, controlling the timing and speed of the stirrer motor, and converting the format of all information displayed or communicated to the user.

[0080] The controller may be configured to execute a calculation routine, such as a software code, for calculating the electromagnetic power output of the electrosurgical instrument. This calculation may be based on a temperature change of the liquid induced by the absorption of the electromagnetic radiation emitted by the electrosurgical instrument. This temperature change may be measured by a temperature sensor and transferred to the controller. The controller may initiate and / or terminate the temperature measurement by controlling the temperature sensor accordingly. The calculation of the electromagnetic power output may also take into account the amount of liquid in the cell container and the heat capacity of the liquid. Both parameters may be entered using a user interface. Alternatively, these types of information may be transferred electronically to the controller. In yet another embodiment, the amount of liquid in the cell container and the heat capacity of the liquid may be stored in the controller and not changed between different measurements. Details of the calculation are described below.

[0081] In an optional embodiment, the controller is configured to control the motor. For this purpose, a controller may be electrically connected to the motor to control the motion of the electric motor, for example, when the measurement is started, the controller starts the motion of the electric motor, and further, the controller may change the speed of motion of the electric motor.

[0082] In an optional embodiment, the electrosurgical instrument calorimeter includes at least one control connector configured to electrically connect the controller to the generator.

[0083] The control connector can be attached to the housing of the calorimeter base and connected to the controller by one or more wires. The control connector allows for an electrical and / or electronic connection between the controller and the generator. Thus, the generator and the controller can electronically communicate with each other. For example, the controller can obtain the intended electromagnetic power output of the electrosurgical instrument and / or the time span during which electromagnetic radiation is emitted into the liquid by the electrosurgical instrument. The former information can be compared to the electromagnetic power output measured using the electrosurgical instrument calorimeter. The latter information can be used to calculate the electromagnetic power output.

[0084] In an optional embodiment, the electrosurgical instrument calorimeter further comprises an external user interface connectable to the controller and / or generator to initiate the emission of the electromagnetic power output of the electrosurgical instrument and / or the measurement of the temperature of the liquid.

[0085] The external user interface may be a foot switch or other type of switch. The external user interface may be used to start a measurement period. The external user interface may generate a start signal when actuated.

[0086] The external user interface may be connected to the generator and / or the controller, for example via a control connector and / or a further connector. A start signal may be received by the generator, prompting the generation of electromagnetic force, for example for a predefined time span. Alternatively or additionally, a start signal may be received by the controller, prompting the controller to start recording the temperature of the liquid.

[0087] However, it is also possible that the start signal is received by the generator and forwarded to the controller, or that the start signal is received by the controller and forwarded to the generator via the above-mentioned connection between the controller and the generator, i.e. the external user interface can only be connected to either the generator or the controller.

[0088] In a further optional embodiment, an initiation signal generated by an external user interface may be received only by the generator, and upon receipt, generation of the electromagnetic force output is initiated. The controller may be configured to determine a temperature change so that the controller does not require an external initiation signal to measure but can determine operation of the electrosurgical instrument.

[0089] The external user interface provides a simple mechanism for initiating measurements and further allows for adjustment of the operation of the generator and the electrosurgical calorimeter.

[0090] In an optional embodiment, the electrosurgical instrument calorimeter may further include an automatic test equipment system connected to the controller and connectable to the generator, and optionally, the automatic test equipment system is configured to communicate with the controller and / or the generator to perform automatic calorimetric measurements.

[0091] The generator and electrosurgical calorimeter may be connected to an automatic test equipment (ATE) system, for example, by wired Ethernet, Wi-Fi, Bluetooth, USB, or a serial connection supporting a communication protocol, such as the commonly used General Purpose Interface Bus (GPIB) or Standard Commands for Programmable Instruments (SCPI), or a proprietary protocol such as the Creo Medical Kamaptive™ protocol.

[0092] The automated test equipment system may include a computer and / or server that operates the automated calorimetry. For example, the automated test equipment system may repeatedly measure the power output of an electrosurgical instrument, which is one example of automated calorimetry. Additionally, the automated test equipment system may control a robot or robotic system of a support structure that may position different types of electrosurgical instruments in a fluid for calorimetry.

[0093] This mode of operation facilitates unattended programmed measurements that can be used to assess reliability and repeatability, such as in validation and verification studies.

[0094] In an optional embodiment, the electrosurgical instrument calorimeter further includes a return electrode disposed within the cell container and, optionally, electrically grounded.

[0095] Electrosurgical instrument calorimeters can be used with bipolar and monopolar instruments alike. For bipolar instruments, the electrical return path or electromagnetic counterpoise is usually the outer shield of the connecting coaxial cable or a separate electrode within the instrument tip assembly. For monopolar operation, the return electrode can be placed inside the cell container to provide conductive contact between the liquid and the instrument tip. Bipolar instruments can also be used in monopolar mode if a monopolar return electrode is connected in the circuit. The monopolar return electrode may comprise a thin foil such as copper, silver or gold, or may be deposited on the surface of the cell container as a conductive coating.

[0096] Electrical grounding of the return electrode may be accomplished by a wire connected to the return electrode which may be connected to the housing or to the surface on which the calorimeter base is placed, or alternatively, the return electrode may be connected to a ground contact on the power supply line that powers the controller and / or temperature sensor.

[0097] In an optional embodiment, the electrosurgical instrument calorimeter further comprises a radiation detector disposed within the calorimeter cell and configured to detect electromagnetic radiation.

[0098] The radiation detector may be any detector capable of detecting electromagnetic radiation within the bandwidth of the radiation emitted by the electrosurgical instrument. For example, the radiation detector may be configured to detect radio frequency radiation or microwave radiation. The radiation detector may be electrically connected to the controller.

[0099] The radiation detector may be located in the cell housing, in the attachment, or in the cell container. Preferably, the radiation detector is located above the liquid in the cell container.

[0100] A radiation detector is provided to detect whether the radiation emitted by the electrosurgical instrument is completely absorbed by the liquid. For example, if the instrument tip is not fully inserted into the liquid, the radiation is not all absorbed by the liquid and therefore contributes to heating of the liquid. Alternatively or additionally, the electrosurgical instrument may include leakage that emits electromagnetic radiation such that the power of the electromagnetic radiation generated by the generator does not correspond to the power emitted at the instrument tip. Detection of electromagnetic fluctuations therefore indicates a measurement artifact.

[0101] The controller can be configured to discard any measurements where the intensity of radiation detected by the radiation detector exceeds a particular threshold. Alternatively or additionally, the controller can be configured to prevent or stop calorimeter measurements if the intensity of the detected radiation exceeds a particular safety threshold indicating a potential danger to the user from electromagnetic radiation emitted by the electrosurgical instrument.

[0102] In an optional embodiment, the electrosurgical instrument calorimeter further comprises an ambient air temperature sensor configured to measure a temperature surrounding the electrosurgical instrument calorimeter.

[0103] The ambient air temperature sensor may be located on the calorimeter base, particularly on or within the housing thereof. The ambient air temperature sensor may be exposed to the surroundings of the electrosurgical instrument calorimeter.

[0104] The temperature detected by the ambient temperature sensor may make it possible to quantify the energy loss in the liquid due to heat transfer from the liquid to its surroundings. Since this type of heat loss depends on the temperature difference between the temperature of the liquid and the temperature of the surroundings, knowing the temperature of the surroundings may help improve the accuracy of the measurement. To this end, the controller may be configured to calculate the energy or power released by the electrosurgical instrument based on the temperature of the surroundings of the electrosurgical instrument calorimeter. To this end, the ambient air temperature sensor may be electronically connected to the controller. The ambient temperature may be measured continuously or at a specific point in time of the measurement of the liquid temperature.

[0105] The air ambient temperature sensor can capture precise temperature measurements over extended periods of time, demonstrating the ability to record data about the electrosurgical instrument calorimeter's environment. The addition of an ambient air temperature sensor can improve the accuracy of the results by allowing correction factors to be applied throughout or after the measurement process to account for more rapid cooling in a cooler ambient environment.

[0106] In an optional embodiment, the electrosurgical instrument calorimeter may further include a heat sensitive filler material configured to be disposed about the instrument tip of the electrosurgical instrument and configured to locally change physical properties upon exposure to electromagnetic radiation, optionally the heat sensitive filler material configured to locally change physical properties in response to the intensity and / or duration of the electromagnetic radiation.

[0107] The heat sensitive filler material may include a heat sensitive gel, tape, and / or other material indicator that may be placed around the emitting tip of the instrument prior to delivering power to the calorimeter. This may provide information regarding the distribution of the energy profile around the geometry of the instrument, an important feature when using the instrument for therapy.

[0108] The material may be of the type that changes color when heated, or may change from a gel state to a solid state, or vice versa, for example in the case of wax. If such a material is used, the calorimeter calculation may also include an additional term that allows for the specific heat capacity and mass of the material indicator to be taken into account. If the material is thin or lightweight compared to the mass of the calorimeter liquid, it may not be necessary to consider the heating of the additional material indicator.

[0109] The heat sensitive filler material may be formed as a cylinder into which the instrument tip can be inserted such that a sleeve of heat sensitive filler material is disposed around the instrument tip.

[0110] A powder (or granular material) may be used instead of a liquid as the absorbing material. The particle size and / or shape of the particles may be such that the powder can be agitated, for example by using a stirrer and / or by rotating the calorimeter cell. In other words, the powder may have flow properties similar or equivalent to those of a liquid. Examples of powder materials are iron ferrite, conductive carbon black, graphite, carbonyl iron, and / or carbon nanotubes. The average particle size may be between 100 nm and 780 nm, and optionally 100 nm, 240 nm, 400 nm, or 780 nm. In general, the average particle size may be selected to match the wavelength of the electromagnetic radiation emitted by the electrosurgical instrument. Optionally, the powder is a mixture of individual components that may be varied to achieve a preferred load impedance. To obtain a specified impedance or material shaping, a non-lossy radiation transparent material such as ceramic or plastic may also be introduced to keep the particles as a solid.

[0111] The absorbing material in solid form may include a material socket for receiving an instrument tip. For example, multiple solids are provided, each solid formed to be received in the cell container, but including different sized and / or shaped sockets for receiving different types of electrosurgical instruments. If the absorbing material is a solid, no stirrer is provided. Multiple temperature sensors may be provided to precisely measure the temperature change, or optionally the temperature profile / distribution / gradient, within the solid absorbing material. The measured temperature gradient may be used to model / calculate / determine the electromagnetic energy or power received by the solid. In this embodiment, at least one temperature sensor may be disposed within the solid absorbing material to increase the accuracy of the measurement of the temperature distribution within the solid. For this purpose, the solid absorbing material may include a connector for connecting the temperature sensor to a controller. The solid absorbing material may include radiation absorbing materials (RAMs) (e.g., a homogenous mixture of iron ferrite, conductive carbon black, graphite, carbonyl iron, and / or carbon nanotubes) and / or metamaterials, such as those used in microwave attenuators and microwave darkrooms.

[0112] In an optional embodiment, the absorbing material includes a metamaterial and at least one absorber, where the metamaterial is configured to guide electromagnetic radiation to the at least one absorber, and the at least one absorber is configured to absorb the electromagnetic radiation.

[0113] For example, metamaterial structures using periodic structures or split ring resonators can be used to guide or focus electromagnetic radiation into smaller thermal absorbers, which can reduce their mass and thereby advantageously increase their temperature for a given power output, shortening the time required to measure. A further advantage is that metamaterial structures can be fabricated to eliminate the need for intimate contact between the solid absorber and the instrument, which can be beneficial in maintaining a sterile environment.

[0114] The absorber can be made of the same materials as described with respect to the solid absorbent material. The mass and / or volume of the one or more absorbers is less than the mass and / or volume of the metamaterial. The absorber may be disposed within the metamaterial. The outer shape of the metamaterial may be formed to be inserted into the cell container. The metamaterial may include a socket for receiving the instrument tip. By providing the metamaterial, the socket may not be exclusively adapted to a particular type of instrument tip. Rather, the socket may have a shape and size configured to receive a number of different instrument tips. That is, the socket may be larger than the instrument tip such that when the instrument tip is in the socket, the outer surface of the instrument tip is spaced from the inner surface of the socket by at least 1 mm, e.g., at least 2 mm or 5 mm.

[0115] At least one temperature sensor may be disposed within or near the at least one absorbent body, in this manner allowing the temperature sensor to precisely measure temperature changes within the absorbent body.

[0116] Optionally, the absorbing material includes a gas and / or plasma that may be ignited (e.g., an arc may be produced) and / or maintained (e.g., sustained) by electromagnetic radiation emitted by the electrosurgical instrument. The lid may be configured to hermetically seal the calorimeter cell.

[0117] The invention also refers to an assembly comprising an electrosurgical instrument calorimeter as described above and an electrosurgical device as described above.

[0118] A method for measuring the electromagnetic energy and / or power output of an electrosurgical instrument powered by a generator includes the steps of: a) filling a calorimeter cell of an electrosurgical instrument calorimeter with a predetermined amount of absorbing material; b) positioning the electrosurgical instrument in a position such that electromagnetic radiation emitted by the electrosurgical instrument (e.g., a majority, or all, or a substantial portion thereof) is absorbed (e.g., completely absorbed) by the absorbing material; c) operating the electrosurgical instrument over a predetermined time span to radiate electromagnetic radiation into the absorbing material; d) measuring the change in temperature of the absorbing material; and e) calculating the energy and / or power of the electromagnetic radiation emitted by the electrosurgical instrument based on the measured change in temperature, the amount of liquid in the calorimeter cell, and / or the time span over which the electromagnetic radiation occurs.

[0119] The methods described above may be used in conjunction with the electrosurgical instrument calorimeters described above, and in particular the properties, features and / or advantages described in relation to the electrosurgical instrument calorimeters may be equally applicable to the methods for measuring the electromagnetic power output of an electrosurgical instrument.

[0120] As mentioned above, the calculation of the electromagnetic power output of the electrosurgical instrument is based on three main parameters: the temperature change induced and detected by the absorption of electromagnetic radiation by the liquid (this is measured using at least one temperature sensor), the amount of liquid in the calorimeter cell (this can be determined by feeding a fixed amount of liquid and / or by weighing the amount of liquid fed into the calorimeter cell), and the time span during which the electromagnetic radiation is generated and emitted by the electrosurgical instrument (this parameter can be set on the generator). Calculations based on these three main parameters assume that the energy losses in the liquid (such as cooling of the liquid) occur over a significantly longer period compared to the heating of the liquid, and that the total power released by the electrosurgical instrument is completely absorbed by the liquid.

[0121] Some of these parameters may be valid for the short time span of the calorie calorimeter measurement (e.g., energy loss due to cooling may not be significant in the short term), while other parameters can be adjusted by calibrating the calorie measurement.

[0122] In an optional embodiment, step b) includes inserting an instrument tip into the depth gauge socket, attaching the electrosurgical instrument with a depth gauge clamp such that the depth gauge clamp is in contact with an opening in the depth gauge socket, closing the calorimeter cell with a lid, and inserting the instrument tip into the lead passage until the depth gauge clamp abuts the lid.

[0123] Step b) may further include holding the electrosurgical instrument in a fixed relationship relative to the calorimeter cell using a support structure.

[0124] In an optional embodiment, step b) includes positioning an energy output port of a waveguide of the electrosurgical instrument above or near the liquid.

[0125] This step can be performed if the electrosurgical instrument includes a waveguide such that the energy output port is positioned directly above or in the liquid.

[0126] Step c) may be performed only after the temperature of the liquid has reached substantially the equilibrium temperature, and optionally the temperature change with respect to the substantially equilibrium temperature is recorded.

[0127] The equilibrium temperature is preferably the temperature at which the liquid will precipitate after an extended period of time, for example the equilibrium temperature corresponds to the ambient temperature if the ambient air temperature is assumed to be constant.

[0128] The equilibrium temperature can be considered to be substantially reached if the standard deviation of the previously recorded temperatures is below a predefined threshold. Alternatively or additionally, the liquid is determined to be substantially at equilibrium temperature if the difference between the liquid temperature and the ambient air temperature is below a particular threshold.

[0129] The temperature of the liquid may change upon insertion of a stirrer or an electrosurgical instrument. Furthermore, if a sufficient amount of time has passed since the previous calorimeter measurement, the temperature of the liquid may not have reached the substantially equilibrium temperature. The determination of the substantially equilibrium temperature may be replaced by a control in which the calorimeter measurement may be performed only after a predetermined time has passed after insertion of an electrosurgical instrument into the liquid or after the previous calorimeter measurement.

[0130] In an optional embodiment, the method further comprises the step of stirring the liquid in the calorimeter cell. A stirrer as described above may be used for this purpose.

[0131] In a further optional embodiment, steps c) and d) are performed automatically after receiving a start signal, and optionally, the controller and generator of the electrosurgical instrument calorimeter are interconnected, and further optionally, the start signal is generated by an external user interface connected to the controller and / or the generator, or by an automatic test equipment system connected to the controller and / or the generator.

[0132] Alternatively, step d) is used to detect the performance of step c). In this embodiment, detection of a change in temperature of the liquid faster than the change in temperature due to heat loss is used to determine that the electrosurgical instrument has emitted electromagnetic radiation into the liquid. In this embodiment, there is no need to provide a connection between the controller and the generator, as the controller can determine the operation of the electrosurgical instrument.

[0133] In an optional embodiment, the presence of electromagnetic radiation in the calorimeter cell is detected and, if the intensity of the detected electromagnetic radiation is above a predefined threshold, the execution of steps c), d) and / or e) is optionally stopped or inhibited. For this purpose, a radiation detector as described above can be used.

[0134] In an optional embodiment, the calculation in step e) is further based on the temperature surrounding the electrosurgical instrument calorimeter, the energy introduced by a stirrer stirring the liquid in the liquid, and / or the heat absorption of the electrosurgical instrument.

[0135] In an optional embodiment, a heat-sensitive filler material is disposed around the instrument tip of the electrosurgical instrument and the electrosurgical instrument is operated or steps b) and c) are performed such that a radiation pattern of the instrument tip of the electrosurgical instrument is identified by local changes in the physical properties of the heat-sensitive filler material induced by irradiation with electromagnetic radiation emitted by the instrument tip.

[0136] A heat-sensitive filler material can be attached to the instrument tip prior to the calorimeter measurement. The heat-sensitive filler material is used to obtain information about the radiation pattern of the instrument tip, which cannot be determined using a calorimeter measurement that can determine the total energy absorbed by the liquid, i.e. the total energy released by the electrosurgical instrument. On the other hand, the heat-sensitive filler material cannot be used to determine the total energy or power released from the instrument tip. Thus, the heat-sensitive filler material and the electrosurgical instrument calorimeter are complementary measurement tools.

[0137] The calculation step e) may further be based on the specific heat capacity of the heat-sensitive filling material and / or the mass of the heat-sensitive filling material.

[0138] These parameters can be used to determine the amount of energy absorbed by the heat-sensitive filling material, i.e. the amount of energy that does not contribute to the heating of the liquid. This aspect is particularly relevant when the temperature change of the liquid is recorded only for a short period of time, such that equilibrium cannot be reached between the heat of the heat-sensitive filling material and the liquid. However, if the mass of the heat-sensitive filling material is small, this aspect may be neglected.

[0139] The calculation of the energy / power output of the electrosurgical instrument can also include the mass and specific heat capacity of the instrument tip immersed in the liquid. The electrosurgical instrument itself absorbs heat and effectively cools the liquid. Therefore, calorimetry can be made more accurate by taking into account the amount of heat absorbed by the electrosurgical instrument.

[0140] Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings in which: [Brief description of the drawings]

[0141] [Figure 1] 1 shows a perspective view of an electrosurgical device. [Diagram 2] FIG. 1 shows a perspective view of an electrosurgical instrument calorimeter. [Diagram 3] 3 shows a perspective view of the electrosurgical instrument calorimeter of FIG. 2 in combination with an electrosurgical instrument of the electrosurgical apparatus of FIG. 1. [Figure 4] A cross-sectional view (left) and a perspective view of the calorimeter cell of the electrosurgical instrument calorimeter are shown. [Diagram 5] FIG. 2 shows a perspective view of the cell container of the calorimeter cell. [Figure 6] FIG. 13 shows a perspective view of another embodiment of a cell container of a calorimeter cell. [Figure 7] FIG. 2 shows a perspective view of the attachment of the calorimeter cell. [Figure 8] FIG. 1 shows a perspective view of two embodiments of a stirrer for an electrosurgical instrument calorimeter. [Figure 9] FIG. 1 shows a top perspective view of the lid of the electrosurgical instrument calorimeter. [Figure 10] 10 shows a bottom perspective view of the lid of FIG. 9. [Figure 11] A perspective view of the depth gauge socket (left) and the depth gauge clamp (right) attached to an electrosurgical instrument is shown. [Figure 12] FIG. 1 shows a top view of an electrosurgical instrument calorimeter. [Figure 13] 1 shows a perspective view of an electrosurgical device, an electrosurgical instrument calorimeter, an external user interface, and a signal cable. [Figure 14] 1 illustrates a perspective view of an electrosurgical device, an electrosurgical instrument calorimeter, an external user interface, and a signal cable in a second connection configuration. [Figure 15] 13 shows a perspective view of an electrosurgical device, an electrosurgical instrument calorimeter, and an external user interface in a third connection configuration. [Figure 16] 1 shows a perspective view of an electrosurgical device, an electrosurgical instrument calorimeter, and an automated test equipment system. [Figure 17] 1 shows a diagram illustrating the different phases of a calorimetric measurement of the temporal change in temperature of a liquid. [Figure 18] FIG. 1 shows a block diagram of a method for measuring the electromagnetic force output of an electrosurgical instrument. [Figure 19] 13 shows a perspective view of another embodiment of an electrosurgical instrument positioned above liquid in a cell container. [Figure 20] 2 shows a cross-sectional view of a heat sensitive filler material disposed around the instrument tip of the electrosurgical instrument of FIG. 1 before (left) and after (right) irradiation with electromagnetic radiation. [Figure 21] 13 shows an exploded view of another embodiment of an electrosurgical instrument calorimeter. [Figure 22] A cross-sectional view (left) and a perspective view of a solid absorbent material are shown. [Diagram 23] 1 illustrates a cross-sectional view of another embodiment of an absorbent material. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0142] FIG. 1 shows a perspective view of an electrosurgical device 10 including a generator 12, a cable 14, and an electrosurgical instrument 16. The generator 12 is configured to generate an alternating current (AC) voltage in the radio frequency range and / or microwave range. The AC voltage is present at a generator output 18 to which the cable 14 can be connected using a cable connector 20. The generator 12 further includes a generator interface 22 that allows the frequency and / or amplitude of the generated voltage to be set. The generator interface 22 may be a touch screen. The voltage can be generated as a continuous wave (CW) or in bursts of short pulses of duration up to several minutes.

[0143] The electrosurgical instrument 16 may be configured as a scoping device that can be inserted into a body cavity. The electrosurgical instrument 16 shown in FIG. 1 may have an instrument tip 24 that is advanced to a target site within the body. The instrument tip 24 is configured to emit electromagnetic radiation. In other words, the instrument tip 24 emits electromagnetic radiation that corresponds to the voltage generated by the generator 12. The instrument tip 24 may include a monopole antenna and / or a dipole antenna. The electromagnetic radiation emitted by the instrument tip 24 is used to ablate / coagulate or cut (remove or stretch) tissue at a target site within the body.

[0144] Cable 14, which may be a coaxial cable, is provided for connecting electrosurgical instrument 16 to generator 12. To this end, a cable connector 20 may be used to connect cable 14 to electrosurgical instrument 16 and / or generator 12. Cable 14 is configured to transmit an AC voltage / current generated by generator 12. In other words, cable 14 is configured to transmit an AC current having a frequency within the radio frequency range and / or microwave frequency range.

[0145] 2 includes a calorimeter base 32, a calorimeter cell 34, and a support structure 36. Optionally, the electrosurgical instrument calorimeter 30 includes a display 38, a user interface 40, a motor 42, a control connector 44, a depth gauge mechanism 46, a controller 48, a stirrer 50, and / or a lid 52.

[0146] The calorimeter base 32 may include a housing 54 and may include additional components to support the various portions of the electrosurgical instrument calorimeter 30. The calorimeter base 32 may be configured to be placed on a table or flat surface. The calorimeter housing 54 may be of standard construction used in laboratory instruments, such as folding sheet metal with molded plastic instrument faces and panels. The housing 54 may house all of the components of the electrosurgical instrument calorimeter 30 listed below.

[0147] The calorimeter cell 34 may include three concentric components as shown in FIG. 4 , an (outer) cell housing 56, an (inner) cell container 58, and a removable attachment 60 used to mechanically secure the smaller cell container 58 inside the larger cell housing 56 for ease of access, although any or all of the components may be combined into a single component if desired.

[0148] The cell housing 56 may be permanently attached to the calorimeter base 32 and / or housing 54 and serves as a receptacle for holding an attachment 60 that houses a cell container 58. It may also include a first connector 62 for contacting a second connector 64 that fits onto the attachment 60 for at least one temperature sensor 66.

[0149] The cell container 58 may be permanently installed inside the top of the attachment 60 and holds a known, fixed mass of absorbent material 110 that is heated by the electrosurgical instrument 16. The absorbent material 110 may be a liquid, a powder of solid particles (e.g., granular material), a solid, a gas, and / or a plasma. In the following, the description of the embodiments of the invention relates to a liquid as an example of the absorbent material 110. However, the invention is not limited thereto. Instead of a liquid, a powder of solid particles, a solid, a gas, and / or a plasma may be used.

[0150] The cell container 58 may be of low mass to reduce the amount of heat energy absorbed from the liquid, and is waterproof and insulated from the liquid to reduce the amount of heat energy dissipated to the surroundings by radiation. A vacuum flask configuration could be used as well, but a mechanically thin plastic insulating material is preferred for its durability, low thermal mass, and rigidity.

[0151] The cell container 58 includes an arrangement of at least one temperature sensor 66 (see FIGS. 5 and 6), which may include a miniature thermistor or other thermal transducer used to provide multiple temperature measurements of the liquid at different locations. For example, placing separate temperature sensors 66 at opposing ends of the cell container 58 allows the electrosurgical instrument calorimeter 30 to identify whether the liquid is sufficiently mixed to prevent the formation of thermal pockets that may affect the accuracy of the overall power measurement. Note that additional temperature sensors may also be placed inside or outside the calorimeter base 32 or attachment to measure and account for ambient air temperature, which may also contribute to the overall measurement accuracy (described below). It is also possible to use a single temperature sensor 66.

[0152] A removable attachment 60 or carrier is used to provide mechanical support and hold the lightweight cell container 58 and its temperature sensor connection 68. In this manner, the attachment 60 allows for easy removal (from the calorimeter base 32) of the cell container 58 and its contents without the need to exercise caution when handling the potentially fragile cell container 58 and its temperature sensor connection 68. At the bottom of the attachment 60 is a second connector 64 that connects the temperature sensor 66 to the controller 48 in the calorimeter base 32 via a first connector 62 that mates within the cell housing 56. These may be spring-loaded connectors or other easy-to-mate connectors for ease of handling.

[0153] The attachment 60 may further be insulated, made from an insulating material, or may include a heat reflector such as aluminum foil or aluminum coated plastic to retain as much heat as possible within the calorimeter cell 34.

[0154] As seen in FIG. 7, the attachment 60 for the cell container 58 can include a temperature sensor connection 68 , such as one or more wires, and a second connector 64 that mates with the first connector 62 of the cell housing 62 .

[0155] Depending on the need, some surgical procedures require the delivery of small amounts of energy to tissue, while other procedures use larger electrosurgical instruments 16 to deliver larger amounts of energy to tissue. The use of a standardized interface of the attachment 60 and second connector 64 for carrying the cell container 58 facilitates the use of various liquid volumes that can be tailored to suit different electrosurgical instruments 16. Small volumes of liquid may be used for low energy measurements and larger volumes of liquid may be used for high energy measurements.

[0156] The electrosurgical instrument calorimeter 30 can be used with bipolar and monopolar electrosurgical instruments 16 as well. In the case of bipolar electrosurgical instruments 16, the electrical return path or electromagnetic counterpoise is typically the outer shield of the connecting coaxial cable 14 or a separate electrode in the instrument tip 24. For monopolar operation, as shown in FIG. 6, a return electrode 70 is placed inside the calorimeter cell 34 (specifically the cell container 58) and makes conductive contact between the liquid and the instrument tip 24. The bipolar electrosurgical instrument 16 may also be used in monopolar mode, provided that a monopolar return electrode 70 is connected in the circuit. The return electrode 70 may be constructed from a thin foil of copper, silver, or gold, or may be deposited on the surface of the cell container 58 as a conductive coating.

[0157] For normal operation at microwave frequencies, the type of liquid inserted into the cell container 58 may be water of suitable purity. The choice of liquid is not limited to any one type, but should be of a type that is similar to the impedance of the tissue with which the electrosurgical instrument 16 is normally used. When using an electrosurgical instrument 16 that delivers infrared energy, it may be appropriate to have the cell container 58 filled with a suitable infrared absorbing material rather than pure water, which allows for a high degree of infrared light penetration. Similarly, when the electrosurgical instrument 16 is required to deliver low frequency RF power, around 400 kHz, it may be appropriate to use a conductive saline solution. Not all electrosurgical instruments 16 and power frequencies are suitable for use with the same single cell container 58, and the use of the attachment 60 facilitates the use of a variety of suitable cell containers 58 and suitable liquids.

[0158] The stirrer 50 distributes the heat from the instrument tip 24 around the liquid inside the cell vessel 58, preventing the formation of heat pockets. Not only can the stirrer 50 mix the liquid both vertically and horizontally, but it can also be of small mass to reduce the amount of thermal energy it removes from the liquid, and it can be slow enough that the frictional energy imparted to the liquid is insignificant compared to the energy being measured. Through software and / or calibration, the electrosurgical instrument calorimeter 30 can calibrate and subtract the mechanical frictional energy component imparted to the liquid from the final power and energy results, allowing the overall measurement to be more accurate.

[0159] Typical stirrer types are shown in Figure 8. The first type (shown on the left) is a stiff helical wire and the second type (shown on the right) is a small impeller such as found on model boats. Other types may include, but are not limited to, magnetically coupled stirrers or ultrasonic stirrers. With the goal of minimizing the overall thermal mass and frictional kinetic energy imparted to the liquid, a preferred embodiment of the invention may use a simple lightweight mechanical stirrer as shown.

[0160] The lid 52 is removable or movable, one embodiment of which is shown in Figures 9 and 10. The lid 52 sits on top of the cell housing 56 and houses a transmission (not shown in Figures 9 and 10) which may include gears, cogs and / or belt drive components for the motor 42 to rotate the stirrer 50. The stirrer 50 is rotatably attached to the lid 52.

[0161] The lid 52 may be hollow inside, forming an air pocket that helps insulate the cell container 58. The bottom of the lid 52 may function as a top for the cell container 58.

[0162] The lid 52 can include a passageway 72 through which the electrosurgical instrument 16 can be inserted into the liquid. The passageway 72 can have a grommet to help retain the electrosurgical instrument 16 as well as reduce the loss of thermal energy through the passageway 72. A depth gauge clamp 74, described below, can be located on the top of the lid 52 to hold the electrosurgical instrument 16 at the correct depth through the passageway 72. A recess or other element in the lid 52 can fit over the depth gauge clamp 74.

[0163] Motor 42 is an electric motor that may be mounted on a motor bracket 76 that is secured to cell housing 56. Motor 42 is not visible in Figures 2 and 3 because it is disposed within housing 54. Only a motor shaft of motor 42 protrudes from housing 54. The motor shaft is attached to lid 52 and may include a cog and / or belt drive system that rotates stirrer 50, which agitates the liquid.

[0164] An alternative location for the motor 42 could be on the lid 52 itself, but in a preferred embodiment the motor 42 is positioned to one side such that there are no electrical connections outside the housing 54.

[0165] The speed of the motor may be switched or varied to affect the proper mixing speed by current limiting, shaft rotation sensing, and / or precise, stepped angle control. This control may be performed by a controller 48 to which the motor 42 is electrically connected.

[0166] The display 38 may include, for example, a 20 by 4 character alphanumeric or graphical display and may display the operating parameters of the electrosurgical instrument calorimeter 30, any measurement results, and / or simple instructions on how to operate the device.

[0167] At the rear of the housing 54 there may be one or more control connectors 44 that allow the electrosurgical instrument calorimeter 30 to be coupled to an external electronic device such as the generator 12. Various control modes may be implemented whereby the electrosurgical instrument calorimeter 30 (particularly the controller 48) controls the generator 12 or the generator 12 controls and triggers the calorimeter measurement process. Alternatively or additionally, an external user interface 78, such as a foot pedal system as commonly used in electrosurgical systems, may be attached to the generator 12 or the control connector 44 to generate an initiation signal to begin the calorimeter measurement. The control connector 44 may be connected to an automated test equipment system 80 that allows for full or partial remote control of the electrosurgical instrument calorimeter 30 and / or the generator 12. The automated test equipment system 80 may include a server and / or computer housing software for providing automated calorimeter measurements.

[0168] An important aspect of providing flexible control options is allowing the microwave power from the generator 12 to be turned on by the electrosurgical instrument calorimeter 30 rather than operated by the user, thereby reducing human error in timing of measurements. The various control options are further described below. The control connector 44 may be connected to a controller 48 via wires that extend into the housing 54.

[0169] The user interface 40 may include one or more user command keys that may be provided on the front instrument panel alongside the display 38. The user interface 40 allows the user to set and control all parameters of the calorimeter operation. The user interface 40 may optionally incorporate a touch-sensitive screen depending on aesthetic or operational needs.

[0170] The calorimeter base 32 may include a controller 48, which may include a microcontroller and electronic circuitry (not shown), that controls through software one, some, or all aspects of the calorimeter operation, including, but not limited to, setting operating parameters, timing power delivery and sequencing temperature measurements, acting on user interface commands, acting on and generating control events to and from the control connector 44, controlling the timing and speed of the motor 42, and converting the format of any information displayed or communicated to the user. The controller 48 is located within a housing 54 and is therefore not visible from the outside (see dashed lines in Figures 2 and 3).

[0171] The support structure 36 may include a stand 82 and an instrument guide clamp 84. The support structure 36, and in particular the stand 82, may be attached to the calorimeter base 32. However, the support structure 36 may be a separate component from the calorimeter base 32.

[0172] The stand 82 can include a rod-like or other support structure that helps hold the electrosurgical instrument 16 and can also be clamped to the calorimeter base 32 for safety. An instrument guide clamp 84 can be attached near the top of the stand 82. The stand 82 provides both vertical and lateral stability for the electrosurgical instrument 16 and the instrument guide clamp 84.

[0173] The instrument guide clamp 84 in combination with the stand 82 holds the electrosurgical instrument 16 upright, centrally and laterally positioned within the liquid inside the calorimeter cell 34 as shown in FIG. 3. The optional depth gauge clamp 74, and / or an additional clamping mechanism on the electrosurgical instrument 16 itself, can provide additional stability within the passageway 72, if needed, depending on the type of electrosurgical instrument 16 being used. There can also be variations in the structure of the instrument guide clamp 84 to accommodate different instruments. For example, laparoscopic instruments include shorter, larger diameter (5 mm), and stiffer shafts compared to endoscopic instruments (2 mm diameter). The instrument guide clamp 84 and stand 82 can be adjusted to allow the electrosurgical instrument 16 to freely swing to multiple positions on or off the calorimeter base 32, for example, the electrosurgical instrument 16 can be initially aligned to the correct operating depth using the depth gauge mechanism 46.

[0174] A depth gauge mechanism 46 may be provided on the calorimeter base 32 (particularly on the housing 54) to facilitate accurate (repeatable and consistent) vertical placement of the instrument tip 24 inside the cell container 58, and thus within the liquid. Accurate positioning is important to maintain repeatability and to ensure that electromagnetic radiation from the instrument top 24 does not escape the calorimeter cell 34. A preferred embodiment is to use a two-part mechanism, as shown in FIG.

[0175] The first part of the depth gauge mechanism 46 is a calibrated depth gauge socket 86 in the housing 54 which temporarily receives the instrument tip 24 prior to use and has a depth which matches the distance from the top of the lid 52 to the center of the cell container 58.

[0176] The second part of the depth gauge mechanism 46 is the depth gauge clamp 74, which may be a collar, clamp or cylinder that fits around the electrosurgical instrument 16 and is adjusted so that when gripped, the instrument tip 24 projects beyond its base by the depth of the depth gauge socket 86 described above. This maintains a consistent operating depth in the liquid. The depth gauge clamp 74 may be fitted with a tightening mechanism to ensure it does not slip during use. Figure 11 shows the depth gauge socket 86 attached to the housing 54 and the depth gauge clamp 74 attached to the electrosurgical instrument 16.

[0177] Additionally, the depth gauge socket 86 may be spaced from the stand 82 at the same radius as the center of the cell container 58, so that the stand 82 can be twisted back and forth above the passage 72 and the depth gauge socket 86, as shown in FIG. 12.

[0178] Alternatively, alternative depth gauge mechanisms 46 can be used, such as a single part system to create a platform within the cell container 58, or by fully or partially automated methods of robotic tool placement, or by optical or ultrasonic sensors.

[0179] Additionally, the alternative depth gauge mechanism 46 may be incorporated into the instrument guide clamp 84 and the clamping mechanism within the stand 82, meaning that a separate instrument depth gauge clamp 74 is not required.

[0180] A variation of the depth gauge mechanism 46 is one in which it is removable for cleaning or replaceable with a disposable unit to maintain a sterile environment.

[0181] To keep the liquid portion of the electrosurgical instrument calorimeter 30 a safe distance from the mains power source, the electrosurgical instrument calorimeter 30 may be powered from the AC mains power supply by a low voltage power converter. For example, a 240V AC to 9V DC power adapter can be used.

[0182] The option of including an internal rechargeable battery located inside the electrosurgical instrument calorimeter 30 (particularly inside the housing 54) and extending the distance from the liquid to the mains power source is contemplated. This would also allow the device to be more mobile. If battery powered, the electrosurgical instrument calorimeter 30 may include an automatic power off feature that detects periods of inactivity and turns itself off to conserve battery power.

[0183] The electrosurgical instrument calorimeter 30 can be connected to operate in a number of flexible modes which offer the advantage of obtaining various measurement types.

[0184] 13 shows a situation where the electrosurgical instrument calorimeter 30 is triggered by the generator 12. A signal cable 88 is connected from the generator 12 to the electrosurgical instrument calorimeter 30 (particularly to the control connector 44). Additionally, an external user interface 78 is connected to the generator 12. In this mode, the generator 12, in response to a user command (start signal) from the external user interface 78, can send appropriate trigger signals to the electrosurgical instrument calorimeter 30 to start and stop the measurement process. This measurement mode is particularly useful to mimic conditions experienced during surgery.

[0185] In Fig. 14, a signal cable 88 is connected from the electrosurgical instrument calorimeter 30 to the generator 12, and an external user interface 78 is connected to the electrosurgical instrument calorimeter 30. In this mode, the electrosurgical instrument calorimeter 30 can respond to user commands from the external user interface 78 by sending trigger signals to the generator 12 to start and stop the power delivery process. This connection mode may be useful for measuring the response time of power delivery. The generator 12 may also be triggered from the user interface 40 of the electrosurgical instrument calorimeter 30 without the use of the external user interface 78.

[0186] 15, the electrosurgical instrument calorimeter 30 and the generator 12 are not connected at all by any signal cable 88. Here, a feature of the electrosurgical instrument calorimeter 30 is that the controller 48 can be programmed to detect and respond to sudden temperature increases compared to the average temperature level (or substantially equilibrium temperature) and statistical variance. This auto-detection mode of operation is particularly useful for simplicity of use.

[0187] 16, the generator 12 and electrosurgical calorimeter 30 may be connected to an automatic test equipment (ATE) system 80, for example, by wired Ethernet, Wi-Fi, Bluetooth, USB, or a serial connection supporting a communication protocol. This protocol may be, for example, the commonly used General Purpose Interface Bus (GPIB) or Standard Commands for Programmable Instruments (SCPI), or a proprietary protocol such as the Creo Medical Kamaptive™ protocol.

[0188] This mode of operation facilitates unattended programmed measurements that can be used to assess reliability and repeatability, such as in validation and verification studies.

[0189] In an optional embodiment of the present invention, the parameters of the electrosurgical instrument calorimeter 30 may be entered using a self-provisioning system, for example, using a code number entered by a user or by a scanner, such as a radio frequency identification (RFID) or optical barcode scanner, capable of identifying the attached electrosurgical instrument 16. This type of automated operation is beneficial in reducing human error, especially during validation and verification exercises.

[0190] The electrosurgical instrument calorimeter 30 may also include an electromagnetic radiation detector 90, for example, within the calorimeter cell 34. Any high levels of electromagnetic radiation detected by the radiation detector 90 may alert the user and terminate power delivery (if properly connected). The accuracy of the electrosurgical instrument calorimeter 30 relies on near 100% absorption of the power from the instrument tip 24 into the liquid; any power that is not absorbed should be considered to produce inaccurate results.

[0191] A method for outputting electromagnetic force in the electrosurgical instrument 30 will now be described. First, the cell container 58 is filled with liquid to the correct depth or mass. This can be accomplished in a number of ways, for example, by weighing the liquid as it is poured into the engaged and disengaged cell container 58 and attachment 60, or by filling the cell container 58 itself to a level marked. In advanced embodiments, a self-fill valve and inlet / outlet system may be fitted to allow the electrosurgical instrument calorimeter 30 to be supplied and replenished with its liquid from an external source. In another advanced embodiment, electronic or mechanical force gauges can be incorporated into the components of the calorimeter cell 34 to measure the weight of the added liquid.

[0192] In the above embodiment, without advanced features, the user can simply input the liquid mass and liquid type into the setting parameters on the user interface 40 or by network connection commands.

[0193] The user can now introduce the filled cell container 58 and attachment 60 into the cell housing 56 and secure the lid 52 and transfer device onto the top of the calorimeter cell 34 .

[0194] The user can then use the depth gauge clamp 74 and depth clamp socket 86 to ensure that the protruding instrument tip 24 is placed at the correct depth in the cell container 58, as shown in FIG.

[0195] Here, the electrosurgical instrument 16 with the depth gauge clamp 74 attached is placed onto the electrosurgical instrument calorimeter 30 using the stand 82 and the instrument guide clamp 84. The instrument tip 24 is inserted through the passage 72 into the cell container 58 and the depth gauge clamp 74 is positioned in contact with the lid 52.

[0196] If the electrosurgical instrument 16 is subsequently required to be used in a sterile environment, the detachable cell container 58, attachment 60 and lid 52 are considered aids in maintaining sterility as they may be easily replaced with new sterile units.

[0197] After the user sets the appropriate parameters, the present invention is ready to take power and energy measurements.

[0198] 17 shows an exaggerated view of temperature measurements made as microwave power is applied to electrosurgical instrument 16 and how these measurements relate to calculated energy and power. Four distinct phases of operation are shown in the measurement process.

[0199] Settling Period: The stirrer 50 is turned on to mix the liquid and equalize its temperature both between successive samples and from the various temperature sensors 66.

[0200] Ready Period: The electrosurgical instrument calorimeter 30, and in particular the controller 48, detects that the variance in the temperature measurements is low enough and presumes that temperature equilibrium has been reached indicating a reliable starting temperature. A signal is presented to the user that the electrosurgical instrument calorimeter 30 is ready to proceed.

[0201] Power Delivery or Heating Period: Microwave energy is delivered to the electrosurgical instrument 16 and absorbed by the liquid. Power delivery can be continuous, at a fixed level, as a variable level, or in bursts. These details can be set in the generator 12.

[0202] Calculation: Power delivery is stopped either by command or detection by the electrosurgical instrument calorimeter 30 (e.g., using the signal cable 88) and a cooling curve can be established. The calculation takes the form of measuring the temperature rise in a known amount of liquid with a known specific heat capacity in a known time. The cooling curve is primarily of negative exponential form.

[0203] While it is possible to simply use the maximum and minimum temperatures recorded to calculate the temperature rise, the present invention may use more accurate methods. Three curves may be established: a) a linear or negative exponential curve fit to the readiness measurements, b) a near linear slope and intercept of the relatively rapid power delivery measurements, and / or c) a linear or negative exponential curve fit to the calculation period measurements.

[0204] The intersection of these curves with each other and refined with precise time stamps by the controller 48 allows more data to be included in the final calculations and can facilitate calculations by the calorimeter software.

[0205] The following formulas are used as the basis for the calorimeter software to calculate the amount of energy and power delivered by the instrument.

[0206] Q=ΔT×M×C (Formula 1) ΔT is the temperature change in degrees Celsius or Kelvin. M is the mass of the liquid in grams and C is the heat capacity of the liquid in Jkg -1 K -1 Multiplying these gives you the heat energy added in Joules, which you divide by the time span over which the energy was delivered (t in seconds) to get the average power input (P in Watts).

[0207] P=Q / t (Equation 2) Example: Applying electricity to 200g of water for 30 seconds will increase its temperature by 2 degrees Celsius (or Kelvin). 2(K)×0.20(kg)×4184(Jkg -1 K -1)=1673.6(J) (Formula 3) 1673.6(J) / 30(s)=55.787(W) (Formula 4) The prototype control and measurement system may be implemented using an Arduino™ processor and coded in C++. The code is divided into seven different phases, blocks or steps, as shown in Figure 18.

[0208] Step S1 is the start phase where the display 38 is turned on and the motor 42 is tested. Furthermore, in this phase, the mass of the liquid used, the heat capacity of the liquid and the experiment time can be set, making the electrosurgical instrument calorimeter 30 more adaptable and allowing the use of different liquids and their volumes.

[0209] Step S2 is a cooling phase in which the electrosurgical instrument calorimeter 30 can obtain the standard deviation of the previous temperature measurements. Furthermore, the motor 42 is turned on to rotate the stirrer 50 so that the thermal energy is evenly distributed in the liquid.

[0210] In step S3, it is determined whether the standard deviation determined in step S2 is less than or equal to a set value. If yes, the method proceeds to step S4, where it moves to a preparation stage. If the standard deviation is greater than the set value, the process returns to step S2 and is repeated until the standard deviation is less than or equal to the set value.

[0211] Step S4 corresponds to a preparation phase and serves as a pause in the process before moving to the heating phase in step S5. To move to step S5, the user may press the go button and / or activate the external user interface 78.

[0212] In the heating phase, step S5, the generator 12 is turned on and an average of the initial temperature is recorded by at least one temperature sensor 66 along with a start timestamp. The heating phase ends when the set time is reached. If the reset button is held during this phase, the test ends prematurely and the electrosurgical instrument calorimeter 30 returns to the start phase (step S1). The electrosurgical instrument calorimeter 30 averages the initial and final temperatures to try to reduce error.

[0213] During cooling after the set duration, a recording (or calculation) phase is entered at step S6, where the motor 42 is turned off and the total time and average final temperature are recorded.

[0214] In the calculation phase of step S7, the electrosurgical instrument calorimeter 30 uses the recorded data to calculate the power and energy input from the instrument to the water. These values ​​are displayed on the screen. The user can then either repeat the process by pressing GO again (which causes the process to move to step S2) or return to the start screen by pressing RESET (which causes the process to move to step S1).

[0215] The electrosurgical instrument calorimeter 30 is capable of capturing precise temperature measurements over extended periods of time and offers the ability to record data regarding its own environment. The addition of an ambient air temperature sensor 92 can improve the accuracy of the results by allowing a correction factor to be applied throughout or after the measurement process to account for more rapid cooling in a cooler ambient environment. The ambient air temperature sensor 92 may be located exposed around the electrosurgical instrument calorimeter 30 as shown in FIGS. 2 and 3 or may be located inside the housing 54. The ambient air temperature sensor 92 is optionally connected to the controller 48 and may be a temperature sensor similar to the temperature sensor 66.

[0216] The electrosurgical instrument calorimeter 30 can also measure the increase in temperature of the liquid as a function of the mechanical energy provided by the stirrer 50, in particular with various stirrer speeds and stirrer geometries. A correction factor can be formed by estimating the mechanical energy provided by the stirrer 50 during the measurement to improve the accuracy of the result. This approximation can be performed by the controller 48, for example based on an algorithm stored in the controller 48. For this purpose, the controller 48 can read the current motor speed.

[0217] The controller 48 may be instructed to establish a curve that fits the temperature measurements before and after the electrosurgical instrument 16 is introduced into the liquid, allowing an estimate of the amount of thermal energy absorbed by the instrument material of the electrosurgical instrument 16. This may be added to the measurement results to improve their accuracy. Different electrosurgical instruments 16 may require different correction factors, which may be applied automatically, for example after using self-provisioning of parameters (see above).

[0218] Some electrosurgical instruments 16 are capable of delivering more than a single electromagnetic frequency, either simultaneously or sequentially. For example, the Creo Medical CROMA system can simultaneously deliver both up to 60 W of 5.8 GHz microwave power and up to 200 W of RF power. The electrosurgical instrument calorimeter 30 may be able to measure the combined output of all the electromagnetic power delivered through the instrument tip 24 of the electrosurgical instrument 16 to the liquid tissue analog. In this case, an appropriate choice of liquid is saline, which readily absorbs radiant, conductive, and capacitively coupled energy.

[0219] By providing an alternative lid 52, or no lid at all, a variety of larger electrosurgical instruments 16 can be accommodated, such as closed, open ended, or filled, rigid or flexible microwave or mm-wave waveguide applicators 94 that can be used to treat tissue surfaces (see FIG. 19). The waveguide applicator 94 typically presents a larger, flatter surface area than a coaxial cable, and may need to be held on the surface of the calorimeter liquid rather than immersed in the liquid, as shown in FIG. 19. The waveguide applicator 94 may include a waveguide 96 in which an antenna 98 is disposed. The antenna 98 is connected to the cable 14 and emits microwave and / or mm-wave radiation into the waveguide 96. The emitted radiation exits the waveguide 96 at a waveguide opening 100, which is an example of an energy output port. For calorimetry, the waveguide opening 100 is positioned directly above the liquid so that a large portion of the emitted electromagnetic radiation, and preferably all of the emitted electromagnetic radiation, is absorbed by the liquid.

[0220] The electrosurgical instrument calorimeter 30 can also be used in combination with a heat-sensitive filler material 102, such as a heat-sensitive gel, tape, or other material indicator. The heat-sensitive filler material 102 can be placed around the instrument tip 24 prior to delivering power to the electrosurgical instrument calorimeter 30. The heat-sensitive filler material 102 can provide information about the distribution of the energy contour around the geometry of the instrument tip 24, an important feature when using the electrosurgical instrument 16 for treatment. The heat-sensitive filler material 102 can be of a type that changes color when heated, or can change from a gel state to a solid state, or vice versa, for example in the case of wax. If a heat-sensitive filler material 102 is used, the calorimeter calculations can also include an additional term that allows the specific heat capacity and mass of the heat-sensitive filler material 102 to be taken into account. If the material of the heat-sensitive filler material 102 is thin or lightweight compared to the mass of the calorimeter liquid, it may not be necessary to consider the heating of an additional material indicator. FIG. 20 shows an example of using a thermal indicator material to indicate the radiation pattern of a device.

[0221] The electrosurgical instrument calorimeter 30 can have a detachable cell container 58 and attachments 60 that are suitable for operation in a sterile environment. When the performance of an instrument is to be measured by the electrosurgical instrument calorimeter 30 and then used in a sterile environment, such as in vivo operations, the use of a detachable liquid cell 34 and the inclusion of a detachable depth gauge socket 86 and lid 52 facilitates maintaining sterility.

[0222] The electrosurgical instrument calorimeter 30 may include various other mechanical features that may improve its usability or accuracy, including, but not limited to, robotic positioning of the electrosurgical instrument 16, data logging to a memory card or network server, audible alarms including voice output of results and commands, automatic power off when used on battery power or DC / mains power, automatic refilling of liquid that becomes too warm due to a combination of valves, pumps, tubing and heat sinks, remote service and data acquisition via an internet link, a method of measuring the mass of liquid in the calorimeter cell 34, such as an electronic balance, and microswitches for detecting correct positioning of the electrosurgical instrument 16 and lid 52.

[0223] 21 shows a further embodiment of an electrosurgical instrument calorimeter 32 in which agitation of the liquid within the calorimeter cell 34 is achieved in a different manner. All other features of the electrosurgical instrument calorimeter 32 may be the same as those described in connection with the other embodiments unless otherwise stated.

[0224] In this embodiment, the motor 42 for rotating the stirrer 50 may not be present. Alternatively or additionally, a stirrer motor 104 is provided, configured to move the calorimeter cell 34. In the embodiment shown in FIG. 21, the stirrer motor 104 generates a rotary motion for rotating the cell vessel 58. In fact, the stirrer motor 104 can rotate the attachment 60 to which the cell vessel 58 is coupled. For this purpose, a spinning disk 106 is attached to the shaft of the stirrer motor 104. The attachment 60 and / or the cell vessel 58 are placed and releasably attached to the spinning disk 106 for rotating the cell vessel 58. The stirrer motor 104 may include features and / or characteristics similar to those of the motor 42. In particular, the stirrer motor 104 may be controlled by the controller 48. In this embodiment, the lid 52 may not be equipped with a transmission means, so that it may have a simpler configuration.

[0225] A stirring means 108 may be provided to stir the liquid in the cell vessel 58, which does not move with the cell vessel 58. For example, the stirring means 108 may be stationary relative to the calorimeter base 32. The lid 52 may be spaced apart from the calorimeter cell 34, allowing the calorimeter cell 34 to move (rotate) relative to the lid 52. Alternatively, one or more bearing elements may be included that physically couple the lid 52 to the cell 34, but also allow for facilitating relative movement between the lid 52 and the cell 34. The stirring means 108 may be attached to the lid 52. The stirring means 108 may include a paddle. The stirring means 108 moves relative to the liquid moving in the moving cell vessel 58, and the stirring means 108 stirs the liquid. The temperature sensor 66 may also be attached to the lid 52. The electrosurgical instrument 16 is positioned stationary relative to the moving calorimeter cell 32. Thus, the temperature sensor 66 and / or the electrosurgical instrument 16 may also agitate the liquid when the calorimeter cell 32 is moving.

[0226] The embodiment shown in FIG. 22 relates to another embodiment of the absorbing material 110 comprising a solid, e.g., radiation absorbing material (RAM) as used in microwave attenuators and microwave darkrooms. Common materials used in the manufacture of RAM are homogeneous mixtures of iron ferrite, conductive carbon black, graphite, carbonyl iron, or carbon nanotubes. The solid absorbing material 110 has an external shape corresponding to the internal shape of the cell container 58. In particular, one diameter of the solid absorbing material 110 is slightly smaller than the inner diameter of the cell container 58 so that the solid absorbing material 110 can be tightly inserted into the cell container 58.

[0227] The solid absorbent material 110 includes a material socket 112 for receiving the instrument tip 24 of the electrosurgical instrument 12. The shape of the material socket 112 is adapted to the shape of the instrument tip 24. Optionally, multiple solid absorbent materials 110 are provided, each having the same external shape but a different shape of the material socket 112. Each solid absorbent material 110 has a material socket 112 that is adapted to receive a different type of electrosurgical instrument 12.

[0228] Optionally, the solid absorbent material 110 includes at least one temperature sensor 66. Preferably, multiple temperature sensors 66 are provided, allowing measurement of a temperature gradient by the solid absorbent material 110. The temperature gradient is generated by absorption of electromagnetic radiation emitted by the instrument tip 24. The measured temperature change and / or temperature gradient may be used to determine the absorbed electromagnetic energy or power. Furthermore, the temperature gradient allows the radial profile of the instrument tip 24 to be determined.

[0229] The embodiment shown in FIG. 23 relates to another embodiment of the absorbing material 110, which includes a metamaterial 114 and an absorber 116. The metamaterial 114 is configured to guide or focus the electromagnetic radiation emitted by the instrument tip 24 to the absorber 116 (as indicated by the arrows in FIG. 23). When the absorber 116 absorbs the electromagnetic radiation, the absorber 116 heats up. This temperature change is measured using a temperature sensor 66, which may be disposed within the absorber 116. The metamaterial 114 may be shaped to be inserted into the cell container 58 and includes a socket for receiving the instrument tip 24. However, in this embodiment, the socket does not have to be shaped to fit the instrument tip 24. In fact, an air gap may be disposed between the instrument tip 24 and the metamaterial 114. The waveguiding properties of the metamaterial 114 allow for essentially all of the emitted electromagnetic radiation to be directed to the absorber 116.

Claims

1. 1. An electrosurgical instrument calorimeter for measuring the electromagnetic energy output of an electrosurgical instrument powered by a generator, comprising: a calorimeter cell for containing an absorbing material configured to absorb electromagnetic radiation; at least one temperature sensor configured to measure a temperature of the absorbent material; and a support structure configured to hold the electrosurgical instrument in a position such that electromagnetic radiation emitted by the electrosurgical instrument is absorbed by the absorbing material; The electrosurgical instrument calorimeter comprising:

2. The electrosurgical instrument calorimeter of claim 1 , further comprising a calorimeter base, optionally wherein the calorimeter cell is attached to the calorimeter base.

3. 3. The electrosurgical instrument calorimeter of claim 2, wherein the calorimeter cell includes a cell housing attached to the calorimeter base, an attachment configured to be releasably attached to the cell housing, and a cell receptacle configured to receive the absorbent material and be disposed within the cell housing.

4. 4. The electrosurgical instrument calorimeter of claim 3, wherein the cell housing and / or the cell container provide thermal insulation for the absorbent material and / or the at least one temperature sensor is located within and / or on the cell container.

5. 5. The electrosurgical instrument calorimeter of claim 3 or 4, wherein the calorimeter cell includes a first electrical connector attached to the cell housing and a second electrical connector attached to the attachment and in electrical communication with the at least one temperature sensor, and optionally, insertion of the attachment into the cell housing connects the second electrical connector to the first electrical connector.

6. 6. The electrosurgical instrument calorimeter of claim 1, wherein the calorimeter cell further comprises a lid for closing the calorimeter cell, and optionally the lid comprises a passage for inserting the electrosurgical instrument into the absorbent material.

7. 7. The electrosurgical instrument calorimeter of claim 1, wherein the absorbent material is a liquid or a powder, and the electrosurgical instrument calorimeter further comprises a stirrer for stirring the liquid or the powder, optionally the stirrer being attached to the lid.

8. 8. The electrosurgical instrument calorimeter of claim 7, further comprising a motor for moving the stirrer, optionally the cell housing further comprising a motor bracket for supporting the motor, and further optionally the lid including a transmission for transmitting motion of the motor to the stirrer.

9. 7. The electrosurgical instrument calorimeter of claim 1, wherein the absorbent material is a liquid or a powder, and the electrosurgical instrument calorimeter further comprises a stirrer motor configured to move the calorimeter cell to agitate the liquid or the powder.

10. 7. An electrosurgical instrument calorimeter according to any one of claims 1 to 6, wherein the absorbent material is solid, and optionally the at least one temperature sensor is disposed within the solid absorbent material.

11. the support structure being supported by a calorimeter base; Optionally, the support structure comprises: an instrument guide clamp for holding the electrosurgical instrument in an upright position; and a stand for supporting the instrument guide clamp, the stand being attached to the calorimeter base; 11. An electrosurgical instrument calorimeter according to any one of claims 2 to 10, comprising:

12. a depth gauge mechanism for facilitating repeatable and consistent placement of an instrument tip of the electrosurgical instrument within the absorbent material; Optionally, the depth gauge mechanism comprises: a depth gauge clamp attachable to the electrosurgical instrument and having an outer diameter greater than a diameter of the passageway; and a depth gauge socket having a depth corresponding to the distance between a distal end of the electrosurgical instrument and an upper surface of the lid within the repeatably consistent position of the electrosurgical instrument; An electrosurgical instrument calorimeter according to any preceding claim, comprising:

13. The electrosurgical instrument calorimeter of claim 12 , wherein the depth gauge socket is disposed on the calorimeter base.

14. a controller configured to calculate the electromagnetic energy output of the electrosurgical instrument based on measurements of the at least one temperature sensor; Optionally, the controller is further configured to control a motor; and / or 14. The electrosurgical instrument calorimeter of any one of claims 1 to 13, wherein the electrosurgical instrument calorimeter includes at least one control connector configured to provide an electrical connection between the controller and the generator and to provide electronic communication between the controller and the generator.

15. 15. The electrosurgical instrument calorimeter of claim 14, further comprising an external user interface connectable to the controller and / or the generator to control the emission of the electromagnetic energy output of the electrosurgical instrument and / or the measurement of the temperature of the absorbing material.

16. The electrosurgical instrument calorimeter of claim 14, further comprising an automatic test equipment system connectable to the controller and connectable to the generator, optionally configured to communicate with the controller and the generator to perform automatic calorimetric measurements.

17. a return electrode disposed within the cell container, the return electrode being optionally electrically grounded; and / or a radiation detector disposed within the calorimeter cell and configured to detect electromagnetic radiation; and / or an ambient air temperature sensor configured to measure a temperature of the ambient air surrounding the electrosurgical instrument calorimeter; 17. The electrosurgical instrument calorimeter of any preceding claim, further comprising:

18. 18. An electrosurgical instrument calorimeter according to any one of claims 1 to 17, further comprising a heat sensitive filler material configured to be disposed around an instrument tip of the electrosurgical instrument and configured to locally change physical properties upon exposure to electromagnetic radiation, optionally the heat sensitive filler material configured to locally change physical properties depending on the intensity and / or duration of the electromagnetic radiation.

19. 1. A method for measuring electromagnetic energy output of an electrosurgical instrument powered by a generator, comprising: a) filling a volume of an absorbing material into a calorimeter cell of an electrosurgical instrument calorimeter, the absorbing material being configured to absorb electromagnetic radiation; b) positioning the electrosurgical instrument in a position such that electromagnetic radiation emitted by the electrosurgical instrument is absorbed by the absorbing material; c) operating the electrosurgical instrument to emit electromagnetic radiation into the absorbing material for a predetermined time span; d) measuring the change in temperature of the absorbent material; and e) calculating the energy of the electromagnetic radiation emitted by the electrosurgical instrument based on the measured change in temperature; and The method includes the steps of:

20. 20. The method of claim 19, wherein step b) comprises: inserting an instrument tip into a depth gauge socket; attaching the depth gauge clamp to the electrosurgical instrument so that the depth gauge clamp contacts an opening in the depth gauge socket; closing the calorimeter cell with a lid; and inserting the instrument tip into the passage of the lid until the depth gauge clamp abuts the lid.

21. 21. The method of claim 19 or 20, wherein step b) further comprises holding the electrosurgical instrument in a fixed relationship relative to the calorimeter cell using a support structure.

22. 21. The method of claim 19 or 20, wherein step b) comprises positioning an energy output port of a waveguide of the electrosurgical instrument proximate the absorbing material.

23. 23. A method according to any one of claims 19 to 22, wherein step c) is carried out after the temperature of the absorbent material has reached a substantially equilibrium temperature, and optionally the change in temperature is recorded with respect to the substantially equilibrium temperature.

24. 24. The method of any one of claims 19 to 23, wherein the absorbing material is a liquid or a powder, the method further comprising agitating the liquid or powder in the calorimeter cell.

25. 25. The method according to any one of claims 19 to 24, wherein steps c) and d) are performed automatically after receiving a start signal, and optionally, a controller and the generator of the electrosurgical instrument calorimeter are interconnected, and further optionally, the start signal is generated by an external user interface connected to the controller and / or the generator, or by an automatic test equipment system connected to the controller and / or the generator.

26. said step d) being used to detect the execution of said step c); and / or The presence of electromagnetic radiation in the calorimeter cell is detected and, optionally, execution of steps c), d) and / or e) is stopped or prohibited if the intensity of the detected electromagnetic radiation exceeds a predefined threshold; and / or 26. The method according to any one of claims 19 to 25, wherein the calculation in step e) is further based on the temperature of the ambient air around the electrosurgical instrument calorimeter, the energy introduced by a stirrer stirring a liquid or powder, and / or the heat absorption of the electrosurgical instrument.

27. 27. The method according to any one of claims 19 to 26, wherein a heat-sensitive filler material is disposed around an instrument tip of the electrosurgical instrument, the electrosurgical instrument is operated or steps b) and c) are performed, and a radiation pattern of the instrument tip of the electrosurgical instrument is identified by a local change in a physical property of the heat-sensitive filler material induced by irradiation with the electromagnetic radiation emitted by the instrument tip.

28. 28. The method of claim 27, wherein the calculation in step e) is further based on the specific heat capacity of the heat-sensitive filler material and / or the mass of the heat-sensitive filler material.

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