Patent Publication Number: US-2017367754-A1

Title: Medical treatment device, method for operating medical treatment device, and treatment method

Description:
CROSS REFERENCES TO RELATED APPLICATIONS 
     This application is a continuation of PCT international application Ser. No. PCT/JP2015/055978, filed on Feb. 27, 2015 which designates the United States, incorporated herein by reference. 
    
    
     BACKGROUND 
     1. Technical Field 
     The disclosure relates to a medical treatment device, a method for operating the medical treatment device, and a treatment method. 
     2. Related Art 
     In recent years, developments of medical treatment devices have been accelerated with which energy is applied to a target to be connected (hereinafter described as a target part) in a body tissue to connect the target part. Such medical treatment devices do not leave a physical object such as a stapler in a body, and therefore have an advantage that there are less adverse effects on a human body. On the other hand, connection strength thereof is weaker than that of the stapler or the like, and there are some target parts which cannot be connected depending on thickness thereof. Therefore, enhancement in connection strength has been demanded. 
     Extracellular matrix (such as collagen or elastin) of a body tissue is constituted by a fibrous tissue. Accordingly, the connection strength is considered to be enhanced by extracting extracellular matrix from a target part and closely tangling the extracellular matrix when connecting the target part. 
     A medical treatment device focused on the extracellular matrix and aimed at enhancement of the connection strength has been proposed (for example, see JP 2012-239899 A). 
     The medical treatment device disclosed in JP 2012-239899 A grasps a target part with a pair of jaws, applies mechanical vibration to the target part (applies ultrasound energy to the target part) via the pair of jaws, thereby enhancing extraction and mixing of the extracellular matrix. 
     SUMMARY 
     In some embodiments, a medical treatment device includes: a pair of holding members configured to grasp a target part to be connected in a body tissue; an energy application portion provided on at least one holding member of the pair of holding members, the energy application portion being configured to contact the target part when the target part is grasped by the pair of holding members to apply energy to the target part; and a processor including hardware. The processor is configured to cause the energy application portion to: apply high-frequency energy to the target part for a first period; apply ultrasound energy to the target part for a second period subsequent to the first period; and apply heat energy to the target part for a third period subsequent to the second period. 
     In some embodiments, a method for operating a medical treatment device includes: after a target part to be connected in a body tissue is grasped by a pair of holding members, applying high-frequency energy to the target part from at least one holding member of the pair of holding members, for a first period; applying ultrasound energy to the target part from at least one holding member of the pair of holding members, for a second period subsequent to the first period; and applying heat energy to the target part from at least one holding member of the pair of holding members, for a third period subsequent to the second period. 
     In some embodiments, a treatment method includes: grasping, by a pair of holding members, a target part to be connected in a body tissue; applying high-frequency energy to the target part from at least one holding member of the pair of holding members, for a first period; applying ultrasound energy to the target part from at least one holding member of the pair of holding members, for a second period subsequent to the first period; and applying heat energy to the target part from at least one holding member of the pair of holding members, for a third period subsequent to the second period. 
     The above and other features, advantages and technical and industrial significance of this invention will be better understood by reading the following detailed description of presently preferred embodiments of the invention, when considered in connection with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a diagram schematically illustrating a medical treatment device according to a first embodiment of the present invention; 
         FIG. 2  is a block diagram illustrating a configuration of a control device illustrated in  FIG. 1 ; 
         FIG. 3  is a flowchart illustrating connection control performed by the control device illustrated in  FIG. 2 ; 
         FIG. 4  is a graph illustrating a behavior of impedance of a target part calculated at Step S 4  or later illustrated in  FIG. 3 ; 
         FIG. 5  is a graph illustrating a behavior of impedance of an ultrasound transducer calculated at Step S 7  or later illustrated in  FIG. 3 ; 
         FIG. 6  is a time chart illustrating types of energy applied, and compression loads applied on a target part, for first to third periods in the connection control illustrated in  FIG. 3 ; 
         FIG. 7  is a chart illustrating a modification of the first embodiment of the present invention; 
         FIG. 8  is a block diagram illustrating a configuration of a medical treatment device according to a second embodiment of the present invention; 
         FIG. 9  is a diagram explaining a function of a lock mechanism illustrated in  FIG. 8 ; and 
         FIG. 10  is a flowchart illustrating connection control performed by a control device illustrated in  FIG. 8 . 
     
    
    
     DETAILED DESCRIPTION 
     Exemplary embodiments of the present invention will be described below with reference to the drawings. The present invention is not limited by the embodiments described below. The same reference signs are used to designate the same elements throughout the drawings. 
     First Embodiment 
     [Schematic Configuration of Medical Treatment Device]  FIG. 1  is a diagram schematically illustrating a medical treatment device  1  according to a first embodiment of the present invention. 
     The medical treatment device  1  applies energy (high-frequency energy, ultrasound energy, and heat energy) to a site as a target (hereinafter described as a target part) of a treatment (connection or anastomosis) in a body tissue to treat the target part. As illustrated in  FIG. 1 , the medical treatment device  1  includes a treatment tool  2 , a control device  3 , and a foot switch  4 . 
     Configuration of Treatment Tool 
     The treatment tool  2  is, for example, a surgical medical treatment tool of a linear type, used for treating a target part through an abdominal wall. As illustrated in  FIG. 1 , the treatment tool  2  includes a handle  5 , a shaft  6 , and a grasping portion  7 . 
     The handle  5  is a portion held by an operator. As illustrated in  FIG. 1 , the handle  5  is provided with an operation knob  51 . 
     The shaft  6  has substantially a cylindrical shape, and one end thereof is connected to the handle  5  ( FIG. 1 ). The grasping portion  7  is attached to another end of the shaft  6 . An opening and closing mechanism  10  (see  FIG. 2 ) is provided inside the shaft  6 . The opening and closing mechanism  10  opens and closes first and second holding members  8  and  9  ( FIG. 1 ) constituting the grasping portion  7  in accordance with an operation of the operation knob  51  by the operator. A motor  11  (see  FIG. 2 ) is provided inside the handle  5 . The motor  11  is connected to the opening and closing mechanism  10 , and when the first and second holding members  8  and  9  grasp a target part, the motor  11  increases a compression load to be applied to the target part from the first and second holding members  8  and  9  by causing the opening and closing mechanism  10  to operate under control of the control device  3 . Furthermore, an electric cable C ( FIG. 1 ) connected to the control device  3  is arranged inside the shaft  6  from one end to the other end thereof via the handle  5 . 
     Configuration of Grasping Portion 
     The grasping portion  7  is a portion for grasping a target part and treating the target part. As illustrated in  FIG. 1 , the grasping portion  7  includes the first holding member  8  and the second holding member  9 . 
     The first and second holding members  8  and  9  are configured to be capable of opening and closing (capable of grasping the target part) in an arrow R 1  ( FIG. 1 ) direction in accordance with an operation of the operation knob  51  by the operator. 
     Specifically, as illustrated in  FIG. 1 , the first holding member  8  is axially supported in a rotatable manner at the other end of the shaft  6 . On the other hand, the second holding member  9  is fixed at the other end of the shaft  6 . In other words, in the first embodiment, the first holding member  8  is configured to be capable of opening and closing with respect to the second holding member  9  in accordance with the operation of the operation knob  51  by the operator. For example, when the operation knob  51  is moved in an arrow R 2  ( FIG. 1 ) direction, the first holding member  8  rotates in a direction close to the second holding member  9 . Alternatively, when the operation knob  51  is moved in an arrow R 3  ( FIG. 1 ) direction, which is opposite to the arrow R 2  direction, the first holding member  8  rotates in a direction away from the second holding member  9 . 
     The first holding member  8  is arranged, in  FIG. 1 , on a side above the second holding member  9 . The first holding member  8  includes a first jaw  81  and a first energy application portion  82 . 
     As illustrated in  FIG. 1 , the first jaw  81  includes an axially supported portion  811  axially supported at the other end of the shaft  6  and a support plate  812  connected to the axially supported portion  811 , and opens and closes in the arrow R 1  direction in accordance with an operation of the operation knob  51  by the operator. 
     The first energy application portion  82  applies high-frequency energy and heat energy to the target part under control of the control device  3 . As illustrated in  FIG. 1 , the first energy application portion  82  includes a heat transfer plate  821  and a heat generation sheet  822 . The heat generation sheet  822  and the heat transfer plate  821  are stacked in this order on a plate surface of the support plate  812  opposite to the second holding member  9 . 
     The heat transfer plate  821  is constituted, for example, by a thin copper plate. 
     When a target part is grasped by the first and second holding members  8  and  9 , a plate surface on a lower side of the heat transfer plate  821  in  FIG. 1  functions as a treatment surface  8211  which contacts the target part. 
     Then, the heat transfer plate  821  transfers heat from the heat generation sheet  822  to the target part from the treatment surface  8211  (applies heat energy to the target part). A high-frequency lead wire C 1  (see  FIG. 2 ) constituting the electric cable C is connected to the heat transfer plate  821 , the control device  3  supplies high-frequency power to between the heat transfer plate  821  and a probe  921  described later via the high-frequency lead wire C 1  and a high-frequency lead wire C 1 ′ (see  FIG. 2 ), and thereby the heat transfer plate  821  applies high-frequency energy to the target part. 
     The heat generation sheet  822  functions as a sheet-type heater. Although specific illustration is omitted, the heat generation sheet  822  has a configuration in which an electric resistance pattern is formed by deposition or the like on a sheet-shaped substrate constituted by an insulating material such as polyimide. 
     The electric resistance pattern is formed along a U-shape following a peripheral shape of the heat generation sheet  822 , and heat-generation lead wires C 2  and C 2 ′ (see  FIG. 2 ) constituting the electric cable C are connected to both ends thereof. Then, the control device  3  applies a voltage to (applies current to) the electric resistance pattern via the heat-generation lead wires C 2  and C 2 ′ to cause the electric resistance pattern to generate heat. 
     Although illustration is omitted in  FIG. 1 , an adhesive sheet is interposed between the heat transfer plate  821  and the heat generation sheet  822  for adhering the heat transfer plate  821  and the heat generation sheet  822  together. The adhesive sheet has high thermal conductivity, withstands high temperatures, and has adhesiveness. The adhesive sheet is formed, for example, by mixing an epoxy resin with ceramics having high thermal conductivity such as alumina, aluminum nitride, or the like. 
     As illustrated in  FIG. 1 , the second holding member  9  includes a second jaw  91  and a second energy application portion  92 . 
     The second jaw  91  is fixed at the other end of the shaft  6 , and has a shape extending along an axial direction of the shaft  6 . 
     The second energy application portion  92  applies ultrasound energy to the target part under control of the control device  3 . The second energy application portion  92  includes the probe  921  ( FIG. 1 ) and an ultrasound transducer  922  (see  FIG. 2 ). 
     The probe  921  is a column constituted by a conductive material, and extending along the axial direction of the shaft  6 . As illustrated in  FIG. 1 , the probe  921  is inserted into the shaft  6  while one end (in  FIG. 1 , a right end) thereof is exposed outside, and the ultrasound transducer  922  is attached to another end thereof. When a target part is grasped by the first and second holding members  8  and  9 , the probe  921  contacts the target part and transmits ultrasound vibration generated by the ultrasound transducer  922  to the target part (applies ultrasound energy to the target part). 
     The ultrasound transducer  922  is configured, for example, by a piezoelectric transducer including a piezoelectric element which extends and contracts by application of an alternating-current voltage. Ultrasound lead wires C 3  and C 3 ′ (see  FIG. 2 ) constituting the electric cable C are connected to the ultrasound transducer  922 , an alternating-current voltage is applied to the ultrasound transducer  922  under control of the control device  3 , and thereby the ultrasound transducer  922  generates ultrasound vibration. 
     Although specific illustration is omitted, a vibration enhancing member such as a horn for enhancing the ultrasound vibration generated by the ultrasound transducer  922  is interposed between the ultrasound transducer  922  and the probe  921 . 
     Here, as a configuration of the second energy application portion  92 , the probe  921  may vibrate longitudinally (vibrate in an axial direction of the probe  921 ), or the probe  921  may vibrate laterally (vibrate in a radial direction of the probe  921 ). 
     Configurations of Control Device and Foot Switch 
       FIG. 2  is a block diagram illustrating a configuration of the control device  3 . 
     In  FIG. 2 , major parts of the present invention are mainly illustrated as the configuration of the control device  3 . 
     The foot switch  4  is operated by a foot of the operator, and outputs an operation signal to the control device  3  in accordance with the operation (ON). Then, the control device  3  starts connection control described later in accordance with the operation signal. 
     Examples of means for starting the connection control include, but are not limited to, the foot switch  4 . A switch operated by a hand, or the like may be employed. 
     The control device  3  integrally controls operations of the treatment tool  2 . As illustrated in  FIG. 2 , the control device  3  includes a high-frequency energy output unit  31 , a first sensor  32 , a heat energy output unit  33 , a transducer driving unit  34 , a second sensor  35 , and a control unit (processor)  36 . 
     The high-frequency energy output unit  31  supplies high-frequency power between the heat transfer plate  821  and the probe  921  via the high-frequency lead wires C 1  and C 1 ′ under control of the control unit  36 . 
     The first sensor  32  detects a voltage and a current supplied to the heat transfer plate  821  and the probe  921  from the high-frequency energy output unit  31 . Then, the first sensor  32  outputs a signal in accordance with the detected voltage and current to the control unit  36 . 
     The heat energy output unit  33  applies a voltage to (applies current to) the heat generation sheet  822  via the heat-generation lead wires C 2  and C 2 ′ under control of the control unit  36 . 
     The transducer driving unit  34  applies an alternating-current voltage to the ultrasound transducer  922  via the ultrasound lead wires C 3  and C 3 ′ under control of the control unit  36 . 
     The second sensor  35  detects a voltage and a current applied to the ultrasound transducer  922  from the transducer driving unit  34 . Then, the second sensor  35  outputs a signal in accordance with the detected voltage and current to the control unit  36 . 
     The control unit  36  is configured to include a central processing unit (CPU) and the like, and executes the connection control in accordance with a predetermined control program when the foot switch  4  is turned ON. As illustrated in  FIG. 2 , the control unit  36  includes an energy controller  361 , a first impedance calculation unit  362 , a second impedance calculation unit  363 , and a load controller  364 . 
     The energy controller  361  controls operations of the high-frequency energy output unit  31 , the heat energy output unit  33 , and the transducer driving unit  34  in accordance with the operation signal from the foot switch  4 , and impedance of a target part and impedance of the ultrasound transducer  922  calculated by the first and second impedance calculation units  362  and  363 , respectively. In other words, the energy controller  361  controls timing for applying high-frequency energy, ultrasound energy, and heat energy to the target part from the first and second energy application portions  82  and  92 . 
     The first impedance calculation unit  362  calculates impedance of the target part when the high-frequency energy is applied to the target part based on the voltage and the current detected by the first sensor  32 . 
     The second impedance calculation unit  363  calculates impedance of the ultrasound transducer  922  when the ultrasound energy is applied to the target part based on the voltage and the current detected by the second sensor  35 . 
     Based on the impedance of the ultrasound transducer  922  calculated by the second impedance calculation unit  363 , the load controller  364  causes the motor  11  to operate, and increases a compression load (force for grasping the target part by the first and second holding members  8  and  9 ) applied to the target part from the first and second holding members  8  and  9 . 
     Operations of Medical Treatment Device 
     Next, operations of the medical treatment device  1  will be described. 
     Here, reference will be made mainly to connection control by the control device  3  as the operations of the medical treatment device  1 . 
       FIG. 3  is a flowchart illustrating the connection control performed by the control device  3 . 
     The operator holds the treatment tool  2 , and inserts a distal end portion (the grasping portion  7  and a part of the shaft  6 ) of the treatment tool  2  into a peritoneal cavity through an abdominal wall, for example, by using a trocar. Then, the operator operates the operation knob  51 , opens and closes the first and second holding members  8  and  9 , and grasps the target part by the first and second holding members  8  and  9  (Step S 1 : grasping step). 
     Then, the operator performs an (ON) operation of the foot switch  4  to cause the control device  3  to start the connection control. 
     When the operation signal from the foot switch  4  is input (the foot switch  4  is turned ON) (Step S 2 : Yes), the energy controller  361  drives the high-frequency energy output unit  31  to start supplying high-frequency power to the heat transfer plate  821  and the probe  921  from the high-frequency energy output unit  31  (start application of high-frequency energy to the target part) (Step S 3 : a first application step). 
     After Step S 3 , the first impedance calculation unit  362  starts calculating impedance of the target part based on the voltage and the current detected by the first sensor  32  (Step S 4 ). 
       FIG. 4  is a graph illustrating a behavior of the impedance of the target part calculated at Step S 4  or later. 
     When high-frequency energy is applied to the target part, the impedance of the target part exhibits the behavior illustrated in  FIG. 4 . 
     As illustrated in  FIG. 4 , the impedance of the target part gradually decreases in an initial time slot (from the start of application of the high-frequency energy to time t 1 ) after applying the high-frequency energy. This is because cell membranes in the target part are disrupted by the applied high-frequency energy and extracellular matrix is extracted from the target part. In other words, the initial time slot is a time slot in which the extracellular matrix is extracted from the target part, so that the viscosity of the target part is decreasing (the target part is in the process of softening). 
     After time t 1  when the impedance of the target part reaches a lowest value VL, the impedance of the target part gradually increases as illustrated in  FIG. 4 . This is because the applied high-frequency energy causes Joule heat to act on the target part to cause the target part itself to generate heat, and thereby moisture in the target part decreases (evaporates). In other words, time slots after time t 1  are time slots in which the extracellular matrix is less and less extracted from the target part and the moisture in the target part evaporates by the generated heat, so that the viscosity of the target part is increasing (the target part is in the process of coagulation). 
     After Step S 4 , the energy controller  361  constantly monitors whether the impedance of the target part calculated by the first impedance calculation unit  362  has reached the lowest value VL (Step S 5 ). 
     When it is determined that the impedance of the target part has reached the lowest value VL (Step S 5 : Yes), the energy controller  361  drives the transducer driving unit  34  to start application of an alternating-current voltage to the ultrasound transducer  922  from the transducer driving unit  34  (start application of ultrasound energy to the target part) (Step S 6 : a second application step). 
     After Step S 6 , the second impedance calculation unit  363  starts calculating impedance of the ultrasound transducer  922  based on the voltage and the current detected by the second sensor  35  (Step S 7 ). 
       FIG. 5  is a graph illustrating a behavior of the impedance of the ultrasound transducer  922  calculated at Step S 7  or later. 
     When ultrasound energy is applied to the target part, the impedance of the ultrasound transducer  922  exhibits the behavior illustrated in  FIG. 5 . 
     The impedance of the ultrasound transducer  922  increases in accordance with a load on the probe  921  when the first and second holding members  8  and  9  grasp the target part. 
     As described above, by the applied high-frequency energy and ultrasound energy, the moisture in the target part evaporates and thus the viscosity thereof increases. Accordingly, after time t 1 , the load on the probe  921  gradually increases since coagulation in the target part proceeds. In other words, the impedance of the ultrasound transducer  922  gradually increases as illustrated in  FIG. 5 . 
     After Step S 7 , the energy controller  361  constantly monitors whether the impedance of the ultrasound transducer  922  calculated by the second impedance calculation unit  363  has reached a predetermined value Th ( FIG. 5 ) (Step S 8 ). 
     When it is determined that the impedance of the ultrasound transducer  922  has reached the predetermined value Th (Step S 8 : Yes), the energy controller  361  stops driving the high-frequency energy output unit  31  and the transducer driving unit  34  (finishes application of the high-frequency energy and the ultrasound energy to the target part) (Step S 9 ). 
     After Step S 9 , the load controller  364  causes the motor  11  to operate to increase a compression load to be applied to the target part from the first and second holding members  8  and  9  (Step S 10 ). 
     After Step S 10 , the energy controller  361  drives the heat energy output unit  33  to start application of a voltage to (application of current to) the heat generation sheet  822  from the heat energy output unit  33  (i.e., start application of heat energy to the target part) (Step S 11 : a third application step). 
     After Step S 11 , the energy controller  361  constantly monitors whether a predetermined time has elapsed after the application of the heat energy in Step S 11  (Step S 12 ). 
     When it is determined that the predetermined time has elapsed (Step S 12 : Yes), the energy controller  361  stops driving the heat energy output unit  33  (finishes application of the heat energy to the target part) (Step S 13 ). 
     Through the above treatments, the target part is connected. 
       FIG. 6  is a time chart illustrating types of energy applied, and compression loads applied on the target part, in first to third periods in the connection control illustrated in  FIG. 3 . 
     Timing for applying each of high-frequency energy, ultrasound energy, and heat energy, and timing for changing a compression load to be applied to the target part are outlined as illustrated in  FIG. 6 . 
     In other words, during the first period T 1  from the foot switch  4  being turned ON to time t 1 , only the high-frequency energy is applied to the target part as illustrated in  FIG. 6 . In the first period T 1 , a compression load applied to the target part from the first and second holding members  8  and  9  is relatively low (for example, about 0.2 MPa). 
     In the second period T 2  which is a period from time t 1  to time t 2 , both of the high-frequency energy and the ultrasound energy are applied to the target part as illustrated in  FIG. 6 . In the second period T 2 , a compression load applied to the target part from the first and second holding members  8  and  9  is the same as that in the first period T 1 . 
     During the third period T 3  from time t 2  until the predetermined time has elapsed, which is determined in Step S 12 , only the heat energy is applied to the target part. In the third period T 3 , a compression load applied to the target part from the first and second holding members  8  and  9  is higher than those in the first and second periods T 1  and T 2 . 
     Here, as described above, in the medical treatment device  1  according to the first embodiment, compression loads applied to the target part from the first and second holding members  8  and  9  when the target part is grasped by the first and second holding members  8  and  9  are adjusted to be higher in the third period T 3  than in the first and second periods T 1  and T 2 . 
     In other words, by adjusting the compression load to be applied to the target part to be higher at coagulation of the extracellular matrix (in the third period T 3 ), tight connection can be achieved. In addition, by adjusting the compression loads applied to the target part to be lower at extraction and stirring of the extracellular matrix (in the first and second periods T 1  and T 2 ), the extracted extracellular matrix can be prevented from flowing out from between the first and second holding members  8  and  9 . In addition, although the higher the compression load applied to the target part at stirring of the extracellular matrix, the more the ultrasound energy (ultrasound vibration) is transmitted to not the target part but the first jaw  81 , by adjusting the compression load to be lower as in the first embodiment, the ultrasound energy (ultrasound vibration) can be efficiently transmitted to the target part. 
     In the medical treatment device  1  according to the first embodiment described above, after a target part is grasped by the first and second holding members  8  and  9 , high-frequency energy is applied for the first period T 1 , ultrasound energy is applied for the second period T 2  subsequent to the first period T 1 , and heat energy is applied for the third period T 3  subsequent to the second period T 2 , to the target part. In other words, cell membranes in the target part are disrupted by the high-frequency energy applied in the first period T 1  to extract extracellular matrix, the extracellular matrix is stirred and closely tangled by the ultrasound energy applied in the second period T 2 , and the extracellular matrix is coagulated by the heat energy applied in the third period T 3 . 
     Therefore, according to the medical treatment device  1  according to the first embodiment, effects can be obtained with which three processes of extraction, stirring, and coagulation of extracellular matrix required to connect a target part can be executed appropriately, and connection strength of the target part can be enhanced. 
     In the medical treatment device  1  according to the first embodiment, the second period T 2  is started and the ultrasound energy is applied to the target part when impedance of the target part reaches the lowest value VL. 
     Accordingly, it is possible to appropriately set the first period T 1  during which the high-frequency energy is applied to the target part to execute a stirring process after extracting a sufficient amount of extracellular matrix from the target part, and as a result, the connection strength of the target part can be further enhanced. 
     In the medical treatment device  1  according to the first embodiment, the third period T 3  is started and the heat energy is applied to the target part when impedance of the ultrasound transducer  922  reaches the predetermined value Th. 
     Accordingly, it is possible to appropriately set the second period T 2  during which the ultrasound energy is applied to the target part to execute a coagulation process after sufficiently stirring the extracellular matrix, and as a result, the connection strength of the target part can be further enhanced. 
     Modification of First Embodiment 
       FIG. 7  is a chart illustrating a modification of the first embodiment of the present invention. Specifically,  FIG. 7  is a flowchart illustrating connection control in the modification. 
     In the first embodiment, the application of the ultrasound energy to the target part is started based on the impedance of the target part and the application of the heat energy to the target part is started based on the impedance of the ultrasound transducer  922  (the compression load to be applied to the target part is increased). Alternatively, the application of each energy described above may be started when a predetermined time has elapsed as in the modification. 
     In other words, in the modification, the first and second sensors  32  and  35  as well as the first and second impedance calculation units  362  and  363  are omitted. In the connection control in the modification, Steps S 4 , S 5 , S 7 , and S 8  are omitted, and Steps S 14  and S 15  are added, as illustrated in  FIG. 7 , to the connection control ( FIG. 3 ) described in the first embodiment. Steps S 4 , S 5 , S 7 , and S 8  relate to calculation of impedance of each of the target part and the ultrasound transducer  922 . 
     Step S 14  is executed after Step S 3 . 
     Specifically, the energy controller  361  constantly monitors in Step S 14  whether a predetermined time has elapsed after the application of the high-frequency energy in Step S 3 . 
     The predetermined time used herein is time set as follows. 
     In other words, each of Steps S 3  to S 5  is executed for a plurality of other body tissues in advance. Then, time taken for impedance of the target part to reach the lowest value VL from the start of the high-frequency energy application is acquired for each body tissue, and an average value of the acquired time is set as the predetermined time to be determined in Step S 14 . 
     When it is determined that the predetermined time has elapsed after the application of the high-frequency energy (Step S 14 : Yes), the control device  3  proceeds to Step S 6 . 
     Step S 15  is executed after Step S 6 . 
     Specifically, the energy controller  361  constantly monitors in Step S 15  whether a predetermined time has elapsed after the application of the ultrasound energy in Step S 6 . 
     The predetermined time used herein is time set as follows. 
     In other words, each of Steps S 3  to S 8  is executed for a plurality of other body tissues in advance. Then, time taken for impedance of the ultrasound transducer  922  to reach the predetermined value Th from the start of the ultrasound energy application is acquired for each body tissue, and an average value of the acquired time is set as the predetermined time to be determined in Step S 15 . 
     When it is determined that the predetermined time has elapsed after the application of the ultrasound energy (Step S 15 : Yes), the control device  3  proceeds to Step S 9 . 
     According to the modification, similar effects to those in the first embodiment can be obtained, and in addition, the configuration can be simplified by omitting the first and second sensors  32  and  35 , as well as the first and second impedance calculation units  362  and  363 . 
     Second Embodiment 
     Next, a second embodiment of the present invention will be described. 
     In the following description, the same reference signs are used to designate the same elements as those in the first embodiment, and detailed descriptions thereof will be omitted or simplified. 
     In the medical treatment device  1  according to the first embodiment, the motor  11  and the load controller  364  are employed to automatically increase a compression load to be applied to the target part at the start of the application of the heat energy. 
     On the contrary, in a medical treatment device according to the second embodiment, a compression load to be applied to a target part at the start of application of heat energy is increased by manual operation. 
     Here, reference will be made to connection control and the configuration of the medical treatment device according to the second embodiment. 
     Configuration of Medical Treatment Device 
       FIG. 8  is a block diagram illustrating a configuration of a medical treatment device  1 A according to the second embodiment of the present invention. 
     In the medical treatment device  1 A according to the second embodiment, the motor  11  and the load controller  364  are omitted as illustrated in  FIG. 8 , in comparison to the medical treatment device  1  ( FIGS. 1 and 2 ) described in the first embodiment. In addition, in the medical treatment device  1 A, a lock mechanism  12  and a lock mechanism driving unit  13  are added and a part of the functions of a control unit  36  is changed, in comparison to the medical treatment device  1  described in the first embodiment. 
       FIG. 9  is a diagram explaining a function of the lock mechanism  12 . Specifically,  FIG. 9  is a diagram illustrating a treatment tool  2 A according to the second embodiment. 
     The lock mechanism  12  is provided inside a handle  5  and is configured to switch an operation knob  51  to a permissive state or to a restrictive state. 
     Specifically, the lock mechanism  12  mechanically connects (locks) the operation knob  51  or an opening and closing mechanism  10  in the restrictive state, thereby restricting movement of the operation knob  51  from a first position P 1  ( FIG. 9 ) to a second position P 2  ( FIG. 9 ). In addition, the lock mechanism  12  mechanically disconnects (unlocks) the operation knob  51  or the opening and closing mechanism  10  in the permissive state, thereby permitting movement of the operation knob  51 . 
     Here, the first position P 1  is a position described below. 
     When the operation knob  51  is moved to the first position P 1  from an initial position (a position of the operation knob  51  illustrated in  FIG. 9 ), a first holding member  8  rotates in a direction close to a second holding member  9 , thereby applying a relatively low compression load (a first compression load (for example, about  0 . 2  MPa)) to a target part grasped between the first holding member  8  and the second holding member  9 . In other words, the first position P 1  is a position where the first compression load is applied to the target part. 
     In addition, the second position P 2  is a position described below. 
     When the operation knob  51  is moved to the second position P 2  from the first position P 1 , the first holding member  8  rotates in a direction closer to the second holding member  9 , thereby applying a second compression load higher than the first compression load to the target part grasped between the first holding member  8  and the second holding member  9 . In other words, the second position P 2  is a position where the second compression load is applied to the target part. 
     In the second embodiment, the lock mechanism  12  is constantly biased by a bias member, such as a spring, so as to mechanically connect (lock) the operation knob  51  or the opening and closing mechanism  10 . 
     The lock mechanism driving unit  13  is provided inside the handle  5 , and is configured to switch the operation knob  51  to the permissive state from the restrictive state by causing the lock mechanism  12  to operate against bias force of the bias member such as a spring under control of a control device  3 A (control unit  36 A). 
     As illustrated in  FIG. 8 , in the control unit  36 A, the load controller  364  is omitted and a lock mechanism controller  365  is added, in comparison to the control unit  36  ( FIG. 2 ) described in the first embodiment. 
     The lock mechanism controller  365  drives the lock mechanism driving unit  13  based on impedance of an ultrasound transducer  922  calculated by a second impedance calculation unit  363  to switch the operation knob  51  to the permissive state from the restrictive state. 
     Connection Control 
     Next, connection control according to the second embodiment will be described. 
       FIG. 10  is a flowchart illustrating connection control performed by the control device  3 A. 
     As illustrated in  FIG. 10 , in the connection control according to the second embodiment, Step S 10  relating to the operation of the motor  11  is omitted, and Steps S 16  and S 17  are added to the connection control ( FIG. 3 ) described in the first embodiment. 
     As described above, in a state where the lock mechanism driving unit  13  is not driven, the lock mechanism  12  is biased by the bias member, such as a spring, so as to mechanically connect the operation knob  51  or the opening and closing mechanism  10  (the operation knob  51  is set to be in the restrictive state). Accordingly, in Step S 1  in the second embodiment, the operator moves the operation knob  51  to the first position P 1  from the initial position, and grasps the target part with the first and second holding members  8  and  9 . In other words, the first compression load is applied to the target part. 
     Step S 16  is executed after Step S 9 . 
     Specifically, the lock mechanism controller  365  drives the lock mechanism driving unit  13  in Step S 16  to switch the operation knob  51  to the permissive state from the restrictive state on condition that it is determined in Step S 8  that the impedance of the ultrasound transducer  922  has reached a predetermined value Th (Step S 8 : Yes). 
     After Step S 16 , the operator moves the operation knob  51  to the second position P 2  from the first position P 1  (Step S 17 ). In other words, the second compression load higher than the first compression load is applied to the target part. 
     After Step S 17 , the control device  3 A proceeds to Step S 11 . 
     According to the second embodiment described above, in addition to similar effects to those in the first embodiment, the following effect can be obtained. 
     In the medical treatment device  1 A according to the second embodiment, the lock mechanism  12  is employed for operation by manual to increase a compression load to be applied to a target part at the start of application of heat energy. 
     Accordingly, the medical treatment device  1 A can be manufactured inexpensively in comparison to the medical treatment device  1  using the motor  11  described in the first embodiment. 
     Modification of Second Embodiment 
     In the second embodiment, application of ultrasound energy or heat energy may be started (the operation knob  51  may be switched from the restrictive state to the permissive state) when a predetermined time has elapsed, as in the modification ( FIG. 7 ) of the first embodiment. 
     In the second embodiment, a notifying unit may be provided to notify the medical treatment device  1 A that the operation knob  51  has been switched from the restrictive state to the permissive state. 
     Examples of the notifying unit include a light emitting diode (LED) for emitting light, a display for displaying messages, and a configuration for producing sound. 
     Other Embodiments 
     Hereinabove, the modes for carrying out the present invention have been described. However, the present invention should not be limited exclusively to the first and second embodiments and the modifications thereof. 
     In the first and second embodiments and the modifications thereof, the first energy application portion  82  is provided on the first holding member  8  and the second energy application portion  92  is provided on the second holding member  9 . Alternatively, an energy application portion for applying energy may be provided on only one of the first and second holding members  8  and  9  as long as high-frequency energy, ultrasound energy, and heat energy can be applied to a target part. Alternatively, each energy application portion may be provided on both of the first and second holding members  8  and  9 . For example, the heat generation sheet  822  and the heat transfer plate  821  may be formed on the probe  921 . 
     In the first and second embodiments and the modifications thereof, the high-frequency energy is applied for the first and second periods T 1  and T 2 , the ultrasound energy is applied for the second period T 2 , and the heat energy is applied for the third period T 3 . Alternatively, two or more types of energy may be simultaneously applied in any period, as with the second period T 2  in the first and second embodiments and the modifications thereof, as long as the high-frequency energy is applied at least for the first period T 1 , the ultrasound energy is applied at least for the second period T 2 , and the heat energy is applied at least for the third period T 3 . 
     In the first and second embodiments and the modifications thereof, the heat generation sheet  822  is employed to apply the heat energy to the target part. Alternatively, a plurality of heat-generating chips may be provided on the heat transfer plate  821 , and current may be applied to the plurality of heat-generating chips to transfer heat of the plurality of heat-generating chips to the target part via the heat transfer plate  821  (for example, regarding the technology, see JP 2013-106909 A). 
     In the first and second embodiments and the modifications thereof, timing for starting application of the ultrasound energy or heat energy, or for increasing a compression load to be applied to the target part is adjusted based on impedance of the target part or the ultrasound transducer  922 , or based on time. Alternatively, the above-described timing may be adjusted based on physical properties such as hardness, thickness, or temperature of the target part. 
     In the first and second embodiments, the application of the ultrasound energy is started when impedance of the target part has reached the lowest value VL. Alternatively, the application of the ultrasound energy may be started at any time after time t 1  when the impedance of the target part reaches the lowest value VL (for example, between time t 1  and time t 1 ′ ( FIG. 4 ) when the impedance reverts to an initial value VI ( FIG. 4 ) at the start of the application of the high-frequency energy). 
     In addition, the flow of the connection control is not limited to the order of processes in flowcharts ( FIGS. 3, 7, and 10 ) described in the first and second embodiments and the modifications thereof, and may be changed without inconsistency. 
     According to some embodiments, it is possible to enhance connection strength of a target part. 
     Additional advantages and modifications will readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details and representative embodiments shown and described herein. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents.