Control device for energy treatment tool, and energy treatment system

A control device is a control device for an energy treatment tool including a first holding member and a second holding member which hold a biological tissue, and a heating element configured to generate heat corresponding to supplied power, thereby heating a holding surface. The control device includes a temperature acquiring section that acquires a temperature of the heating element; and a surface temperature estimating section that estimates, as a surface temperature, a temperature of at least a part of a surface of the first holding member which is different from a portion facing the second holding member, based on a change of the temperature of the heating element after supply of the power is stopped.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a control device for an energy treatment tool, and an energy treatment system.

2. Description of the Related Art

There is known a surgical treatment tool which holds a biological tissue to apply heat energy to the biological tissue, thereby performing a treatment to coagulate or incise the biological tissue. For example, in Jpn. Pat. Appln. KOKAI Publication No. 2005-253789, a surgical treatment tool is disclosed in which a heating element having a resistance heating pattern is disposed in forceps.

In such a treatment tool as mentioned above, it is preferable that in a holding portion holding the biological tissue, a temperature of a holding surface that comes in contact with the biological tissue only rises and a temperature of a portion other than the holding surface does not rise. However, when the treatment to the biological tissue is repeatedly performed, the temperature of the portion other than the holding surface in the holding portion also rises.

BRIEF SUMMARY OF THE INVENTION

According to an aspect of the invention, a control device for an energy treatment tool comprising a first holding member configured so that a holding surface comes in contact with a biological tissue, a second holding member that is configured to open and close relatively to the first holding member to hold the biological tissue between the first holding member and the second holding member, and a heating element configured to generate heat corresponding to supplied power, thereby heating the holding surface, includes a temperature acquiring section that acquires a temperature of the heating element; and a surface temperature estimating section that estimates, as a surface temperature, a temperature of at least a part of a surface of the first holding member which is different from a portion facing the second holding member, based on a change of the temperature of the heating element after supply of the power is stopped.

According to an aspect of the invention, an energy treatment system includes the control device; and an energy treatment tool comprising the first holding member, the second holding member, and the heating element.

DETAILED DESCRIPTION OF THE INVENTION

One embodiment of the present invention will be described with reference to the drawings.FIG. 1shows one example of a configuration example of an energy treatment system according to the present embodiment. An energy treatment system10is a device for use in a medical treatment of a biological tissue. The energy treatment system10applies heat energy to the biological tissue. The energy treatment system10comprises a control device100, an energy treatment tool200, and a foot switch310.

The energy treatment tool200is, for example, a linear type of treatment tool for a surgical treatment which is passed through an abdominal wall to perform a treatment. The energy treatment tool200has a handle250, a shaft240attached to the handle250, and a holding portion210disposed at a distal end of the shaft240. The holding portion210is openable and closable to hold the biological tissue of a treatment target, thereby performing a treatment such as coagulation or incision of the biological tissue. Hereinafter, for the description, a holding portion210side will be referred to as a distal side and a handle250side will be referred to as a proximal side. The handle250comprises operation knobs252to operate the holding portion210. Furthermore, in the handle250, there is disposed an unshown memory to store a proper value or the like concerned with the energy treatment tool200. It is to be noted that needless to say, a shape of the energy treatment tool200mentioned herein is one example, and the tool may have another shape as long as the tool has a similar function.

The handle250is connected to a control device100via a cable260. Here, the cable260is connected to the control device100by a connector265, and this connection is removable. That is, an energy treatment system10is configured so that the energy treatment tool200can be changed every treatment. The control device100is connected to the foot switch310. The foot switch310to be operated by foot may be replaced with a switch to be operated by hand or another switch. An operator operates a pedal of the foot switch310, thereby switching on/off supply of energy from the control device100to the energy treatment tool200.

An outline of a configuration example of the holding portion210will be described with reference toFIG. 2of a configuration view. The holding portion210has a first holding member212and a second holding member214. The first holding member212and the second holding member214are relatively displaced and a biological tissue900is held between the first holding member212and the second holding member214. A surface of the first holding member212which faces the second holding member214and comes in contact with the biological tissue is referred to as a holding surface. Furthermore, a surface opposite to the holding surface of the first holding member212is referred to as a back surface.

A treating portion222made of a metal having a good thermal conductivity, e.g., copper is disposed in the holding surface of the first holding member212. On a back surface side of the treating portion222, a heating element224is disposed. The heating element224includes a resistance pattern that is a lead wire having a high electric resistance, and generates heat when a current flows through the resistance pattern. On a back surface side of the heating element224, there is disposed an insulating member226made of a material having a low thermal conductivity. In the first holding member212, a portion other than the treating portion222, the heating element224and the insulating member226is defined as a holding member main body228.

When power is supplied to the heating element224, the heating element224generates heat. The heat generated by the heating element224is transferred through the treating portion222having a high thermal conductivity to heat the biological tissue900. Furthermore, the heat generated by the heating element224is insulated by the insulating member226having a low thermal conductivity, but a part of the heat is transferred to the back surface of the first holding member212via the insulating member226. For example, the back surface of the first holding member212is a portion having the possibility of coming into contact with a tissue other than the treatment target, when the energy treatment tool200is used. There is a possibility that the tissue other than the treatment target is heated to damage the tissue when a temperature of the back surface becomes a high temperature. Therefore, it is necessary to acquire the temperature of the back surface and maintain the temperature of the back surface at a temperature that is not high. Here, the temperature that is not high is a temperature at which, for example, protein is not denatured.

An outline of a configuration example of the control device100will be described with reference toFIG. 3. The control device100has a control section110, a storage section120, a heating element driving circuit130, a temperature acquiring section140, a surface temperature estimating section150, an input section160, a notification control section170, a display section180, and a speaker190.

The control section110is connected to each section in the control device100, and controls each section of the control device100. The foot switch310is connected to the control section110, and an on-signal indicating that the treatment by the energy treatment tool200is to be performed and an off-signal indicating that the treatment is to be stopped are input from the foot switch310to the control section. The control section110calculates the power to be applied to the heating element224. The control section110causes the heating element driving circuit130to apply the calculated power into the heating element224.

The storage section120includes, for example, a usual semiconductor memory. In the storage section120, various types of programs, data and the like required for an operation of the control device100are stored. The control section110operates in accordance with, for example, the program stored in the storage section120.

The heating element driving circuit130is connected to the energy treatment tool200, and drives the heating element224of the energy treatment tool200under control of the control section110. That is, the heating element driving circuit130supplies the power to the resistance pattern of the heating element224under the control of the control section110.

The temperature acquiring section140has a function of acquiring voltage to be applied from the heating element driving circuit130to the heating element224and current at this time, and acquiring a resistance value of the resistance pattern of the heating element224on the basis of the voltage and the current. The resistance value of the resistance pattern changes in accordance with a temperature of the resistance pattern. The storage section120stores a relation between the temperature and the resistance value of the resistance pattern which is acquired beforehand. The temperature acquiring section140calculates the temperature of the resistance pattern on the basis of the acquired resistance value of the resistance pattern by use of the relation between the temperature and the resistance value of the resistance pattern. The temperature acquiring section140outputs the obtained temperature of the resistance pattern, i.e., the temperature of the heating element224to the surface temperature estimating section150.

The surface temperature estimating section150estimates, as a surface temperature, a temperature of at least a part of the surface of the first holding member212excluding the surface of the first holding member212which faces the second holding member214. Examples of the surface from which the surface temperature is estimated include a back surface and a side surface of the holding member main body228. The surface temperature estimating section150acquires the temperature of the heating element224from the temperature acquiring section140. The surface temperature estimating section150estimates the surface temperature on the basis of characteristics of a temperature decrease of the heating element224after stop of power supply to the heating element224.

The input section160includes a usual input device such as a button, a knob or a keyboard. Various settings and the like of the control section110are input into the input section160. The input section160outputs the input information to the control section110. The notification control section170controls operations of the display section180and the speaker190. The display section180displays various settings and the like of the control section110. The speaker190outputs an alarm sound and the like.

The control section110, the temperature acquiring section140, the surface temperature estimating section150, the notification control section170or the like includes, for example, a central processing unit (CPU) or an application specific integrated circuit (ASIC).

Next, an operation of the energy treatment system10according to the present embodiment will be described. The operator beforehand operates the input section160of the control device100to set output conditions of the energy treatment system10, e.g., a target temperature, a heating time or the like of the heating by heat energy output. In the energy treatment system10, respective values may individually be set, or setting of a set value in accordance with an operation system may be selected.

The holding portion210and the shaft240of the energy treatment tool200are inserted into, for example, an abdominal cavity through the abdominal wall. The operator operates the operation knobs252to open and close the holding portion210and holds the biological tissue of the treatment target by the first holding member212and the second holding member214. At this time, the holding surface of the treating portion222of the first holding member212comes in contact with the biological tissue of the treatment target.

On holding the biological tissue of the treatment target by the holding portion210, the operator operates the foot switch310. When the foot switch310is switched on, the power is supplied from the control device100to the heating element224via the cable260so that a temperature of the holding surface of the first holding member212is the target temperature. Here, the target temperature is, for example, 200° C. The current at this time flows through the resistance pattern of the heating element224from the control device100via the cable260. The resistance pattern of the heating element224generates heat by the current. The heat generated by the resistance pattern is conducted to the treating portion222. As a result, a temperature of the treating portion222rises. Due to the temperature rise of the treating portion222, the biological tissue that is in contact with the treating portion222is burnt out and coagulated. When the biological tissue is heated to coagulate, the output of the heat energy stops. It is to be noted that when the target temperature of the holding surface is, for example, 300° C., the biological tissue is cut at this high temperature. The treatment of the biological tissue is completed as described above.

The operation of the control device100will further be described with reference to a flowchart shown inFIG. 4.

In step S101, the control section110determines whether or not the foot switch310switches on, i.e., whether or not to turn on the heat generation by the heating element224. When it is determined that the heat generation is not turned on processing returns to step S101. That is, the control section110repeats the processing of step S101until the foot switch310switches on. When it is determined in step S101that the heat generation turns on, the processing advances to step S102.

In step S102, the control section110controls an operation of the heating element driving circuit130to supply the power to the heating element224. As a result, the current flows through the heating element224and the heating element224generates heat. The heat generated by the heating element224is transferred to the treating portion222and the biological tissue in contact with the treating portion222is heated. At this time, the control section110executes feedback control of an output from the heating element driving circuit130. That is, the control section110acquires, from, the temperature acquiring section140, the temperature of the heating element224which is calculated on the basis of the resistance value of the resistance pattern, and executes the feedback control of the output from the heating element driving circuit130so that the temperature of the treating portion222becomes the target temperature on the basis of the temperature of the heating element224.

In step S103, the control section110determines whether or not the foot switch310is turned off, i.e., the heat generation by the heating element224should be turned off. When it is determined that the heat generation is not turned off, the processing returns to step S102. That is, the power supply to the heating element224is continued. When it is determined in step S103that the heat generation is turned off, the processing advances to step S104. At this time, the power supply to the heating element224stops.

In step S104, the control section110causes the temperature acquiring section140to acquire the temperature of the heating element224simultaneously with or immediately after the stop of the power supply to the heating element224. That is, the temperature acquiring section140acquires a voltage value of the voltage applied to the heating element224and a current value of the current flowing at this time from the heating element driving circuit130. The temperature acquiring section140calculates the resistance value of the resistance pattern of the heating element224on the basis of the acquired voltage value and current value. The temperature acquiring section140acquires information indicating a relation between the resistance value of the resistance pattern of the heating element224and the temperature of the heating element224which is stored in the storage section120via the control section110, and the temperature acquiring section140calculates the temperature of the heating element224on the basis of the information. The temperature acquiring section140outputs the calculated temperature of the heating element224to the surface temperature estimating section150. Such calculation of the temperature of the heating element224and the output of the temperature to the surface temperature estimating section150are performed at appropriate timings.

In step S105, the control section110causes the surface temperature estimating section150to estimate a temperature of the surface of the first holding member212as the surface temperature. Here, the temperature estimated as the surface temperature is a temperature of a portion different from a portion facing the second holding member214in the surface of the first holding member212, and is, for example, a temperature of a portion of a back surface or a side surface of the first holding member212. The surface temperature is calculated on the basis of the temperature change of the heating element224after the supply of the power to the heating element224is stopped.

FIG. 5Ashows one example of the temperature change of the heating element224to elapsed time. At time T0, the power supply to the heating element224is started. At this time, the temperature of the heating element224rises with the elapsed time. Consequently, when the temperature of the heating element224reaches a first temperature temp1that is the target temperature, the power to be supplied to the heating element224is adjusted by the control section110, and the temperature of the heating element224is maintained at a first temperature temp1. It is defined that the power supply to the heating element224is stopped at time T1. At this time, the temperature of the heating element224decreases with the time. That is, the heat of the heating element224is transferred to the holding member main body228or the like and is radiated to the environment from the surface of the holding member main body228, e.g., the back surface or the side surface of the first holding member212, or the like.

In the example shown inFIG. 5A, the temperature of the heating element224becomes a second temperature temp2at time T2. That is, in the example shown inFIG. 5A, from the time T1to the time T2, the temperature of the heating element224decreases as much as a temperature difference Δtemp1from the first temperature temp1to the second temperature temp2. Here, Δtemp1=temp1−temp2.

FIG. 5Bshows one example of the temperature change of the heating element224to the elapsed time in a case where the surface temperature such as the temperature of the back surface of the first holding member212is higher than that shown inFIG. 5A. Also in the case shown inFIG. 5B, the power supply to the heating element224is started at the time T0, the temperature of the heating element224is maintained at the first temperature temp1, and then at the time T1, the power supply to the heating element224is stopped. In the example shown inFIG. 53, from the time T1to the time T2, the temperature of the heating element224decreases as much as a temperature difference Δtemp2from the first temperature temp1to a third temperature temp3. Here, Δtemp2=temp1−temp3. Δtemp2is smaller than Δtemp1. That is, the higher the surface temperature is, the smaller the temperature decrease of the heating element224after the power supply to the heating element224is stopped per predetermined time becomes. In this way, when the temperature decrease of the heating element224to the elapsed time is measured, for example, the surface temperature of the back surface or the like can be estimated.

Transfer of the heat from a first region to a second region is represented by a heat conduction equation mentioned below. That is, Equation (1) of a quantity of the heat to be transferred per unit is established as follows:
Q/T=KS(Δtemp)/L=KS(tempA=tempB)/L(1),
where Q is a quantity of the heat to be transferred from the first region to the second region, K is a thermal conductivity of a heat transferring member, S is an area of a portion through which the heat transfers, L is a distance along which the heat transfers, T is elapsed time, tempA is a temperature of the first region, tempB is a temperature of the second region, and Δtemp is a temperature difference between the first region and the second region.

Here, the thermal conductivity K, the area S and the distance L of the whole first holding member212are beforehand obtained and stored in, for example, the storage section120. When the temperature of the heating element224is acquired as the temperature tempA of the first region and the quantity Q/T of the heat to be transferred per unit time is acquired as the temperature decrease, for example, the temperature of the back surface can be estimated as the temperature tempB of the second region.

It is to be noted that the information of the thermal conductivity K, the area S and the distance L of the whole first holding member212can be acquired by, for example, experiments. The information of the thermal conductivity K, the area S and the distance L of the whole first holding member212may be stored in a memory disposed in the energy treatment tool200. In this case, the control device100reads the information from the memory disposed in the energy treatment tool200.

The temperature tempB of the second region which is the surface temperature of the first holding member212may be calculated by calculation on the basis of Equation (1) mentioned above. Furthermore, the temperature tempB of the second region may be obtained by referring a relation between the temperature tempB of the second region and each of the temperature tempA of the first region per unit time and the quantity Q/T of the heat to be transferred, which is stored, for example, as a table in the storage section120.

As described above, the surface temperature estimating section150estimates the surface temperature on the basis of the temperature change of the heating element224after the power supply. The surface temperature estimating section150transmits the estimated temperature to the control section110.

In step S106, the control section110determines whether or not the surface temperature estimated by the surface temperature estimating section150is higher than a predetermined threshold value. Here, the predetermined threshold value may be set to any degrees centigrade, but is set to, for example, 60° C. When it is determined that the surface temperature is not more than the predetermined threshold value, the processing advances to step S108. On the other hand, when the surface temperature is higher than the predetermined threshold value, the processing advances to step S107.

In step S107, the control section110performs high temperature processing. In the high temperature processing, the processing is performed so that the surface temperature does not heighten to cause any problems. The high temperature processing will be described later. After the high temperature processing, the processing advances to step S108.

In step S108, the control section110determines whether or not to end the processing. For example, when the input section160inputs an instruction to end the processing, the processing ends. When it is determined that the processing is ended, the processing ends. On the other hand, when it is determined that the processing is not ended, the processing returns to step S101.

One example of the high temperature processing will be described with reference to a flowchart shown inFIG. 6. In the example shown inFIG. 6, the supply of the power to the heating element224is stopped until the surface temperature reaches the predetermined threshold value or less.

In step S201, the control section110causes the notification control section170to notify that the surface temperature is a temperature higher than a predetermined temperature. The notification control section170causes, for example, the display section180to display that the surface temperature is the high temperature and that due to the high temperature, the power is not supplied to the heating element224. Furthermore, the notification control section170may output, from the speaker190, voice indicating that the surface temperature is the high temperature and that due to the high temperature, the power is not supplied to the heating element224. Afterward, the processing advances to step S202.

In step S202, the control section110determines whether or not the surface temperature is higher than the predetermined threshold value. When it is determined that the surface temperature is higher than the predetermined threshold value, the processing returns to step S201. Therefore, while the surface temperature is higher than the predetermined threshold value, it continues to be notified that the surface temperature is the high temperature without supplying the power to the heating element224. When the surface temperature is not more than the predetermined threshold value in step S202, the processing returns to the processing described with reference toFIG. 4.

Another example of the high temperature processing will be described with reference to a flowchart shown inFIG. 7. In the example shown inFIG. 7, the power to be supplied to the heating element224is adjusted into a low level until the surface temperature reaches the predetermined threshold value or less.

In step S301, the control section110determines whether or not the foot switch310switches on and the heat generation is turned on. When it is determined that the heat generation is not turned on, the processing advances to step S307. On the other hand, when it is determined that the heat generation is turned on, the processing advances to step S302.

In step S302, the control section110causes the heating element driving circuit130to supply low power to the heating element224. Here, the power to be supplied to the heating element224by the heating element driving circuit130has a level lower than that of the power supplied to the heating element224by the heating element driving circuit130in step S102of the processing described with reference toFIG. 4. The supplied power is suppressed to the low level, whereby the rise of the surface temperature is suppressed.

In step S303, the control section110causes the notification control section170to notify that the output by the heating element224is the low level. By this notification, the user can know that the current output is the low level.

In step S304, the control section110determines whether or not to turn off the heat generation. When it is determined that the heat generation is not turned off, the processing returns to step S302. As a result, the supply of the low level power to the heating element224is continued. On the other hand, when it is determined that the heat generation is turned off, the processing advances to step S305. At this time, the power supply to the heating element224is stopped.

In step S305, the control section110causes the temperature acquiring section140to acquire the temperature of the heating element224on the basis of the resistance value of the resistance pattern of the heating element224. In step S306, the control section110causes the surface temperature estimating section150to estimate the surface temperature on the basis of the temperature decrease of the heating element224.

In step S307, the control section110determines whether or not the surface temperature is higher than the predetermined threshold value. When it is determined that the surface temperature is higher than the predetermined threshold value, the processing returns to step S301. On the other hand, when it is determined that the surface temperature is not more than the predetermined threshold value, the processing returns to the processing described with reference toFIG. 4.

According to the high temperature processing shown inFIG. 7, while the surface temperature is higher than the predetermined threshold value, the power supplied to the heating element224is suppressed to the low level, and when the surface temperature is not more than the predetermined threshold value, the processing returns to usual processing. It is to be noted that the power supplied in step S302may be a constant power different from the usual supply power, a power obtained by multiplying the usual supply power by a predetermined coefficient, or a power corresponding to the surface temperature. It is preferable that the higher the surface temperature is, the smaller the power to be supplied becomes, so that the surface temperature becomes lower than the predetermined threshold value quickly.

As described above, according to the present embodiment, control is executed so that the surface temperature of the first holding member212does not heighten. In this case, the surface temperature is estimated on the basis of the temperature of the heating element224without being directly measured. Therefore, according to the present embodiment, it is not necessary to dispose a temperature sensor to measure the surface temperature separately from a mechanism to measure the temperature of the heating element. It is to be noted that it is necessary to acquire the temperature of the heating element,224for the control to maintain the temperature of the heating element224at the target temperature.

As described above, according to the present embodiment, the surface temperature can be acquired by a simple method while simplifying the configuration of the first holding member212. Furthermore, by use of the acquired surface temperature, it is possible to avoid bad influences such as a failure of the energy treatment tool200due to the rise of the surface temperature of the first holding member212and a damage of the biological tissue due to the fact that the high-temperature back surface or the like unexpectedly comes in contact with the biological tissue. Furthermore, the estimating of the surface temperature on the basis of the temperature change of the heating element224produces effect in miniaturization of the first holding member212.

It is to be noted that in the present embodiment, the temperature of the heating element224is acquired on the basis of an electric resistance value of the resistance pattern of the heating element224. In this way, when the temperature is acquired on the basis of the resistance value, a temperature sensor is not required separately from the heating element224. This produces effect in the miniaturization of the first holding member212.

As described above, a temperature acquiring method of the heating element224is not limited to a method of acquiring the temperature on the basis of the resistance value of the resistance pattern of the heating element. The temperature sensor may be disposed in the vicinity of the heating element224to acquire temperature information of the heating element224from the temperature sensor.

Furthermore, in the above-mentioned embodiment, when the surface temperature is higher than the predetermined threshold value, the supply of the power to the heating element224may continue as usual, and it may only be notified that the surface temperature is high. The user who can recognize that the surface temperature is high can perform the treatment while being careful so that the back surface or the like does not come in contact with another tissue or the like.

Furthermore, in the above-mentioned embodiment, there has been described the example in which a heat generating mechanism such as the heating element224is only disposed in the first holding member212, but the present invention is not limited to this embodiment, and the heat generating mechanism may also be disposed in the second holding member214in the same manner as in the first holding member212.