Patent Publication Number: US-2022227017-A1

Title: Method for vibrating handpiece-type high-frequency vibration apparatus

Description:
TECHNICAL FIELD 
     The present invention relates to a method for vibrating a handpiece-type high-frequency vibration apparatus which performs cutting using a tool attached to a distal end portion. 
     BACKGROUND ART 
     A handpiece-type high-frequency vibration apparatus which comprises a handpiece including a vibrating body (vibrator) that ultrasonically vibrates, and cuts an object using a tool (processing unit) attached to a distal end portion is known (for example, Patent Literature 1). 
     In the handpiece-type high-frequency vibration apparatus described in Patent Literature 1, an ultrasonic vibration transmission member for transmitting vibrations at the vibrating body to the tool is provided, and the ultrasonic vibration transmission member is fixedly connected to the vibrating body in an undetachable state. 
     When cutting is performed with the handpiece-type high-frequency vibration apparatus described in Patent Literature 1, since cutting easiness and cutting time vary depending on a frequency of the tool, the frequency of the tool is generally turned to a resonance frequency of the tool. 
     CITATION LIST 
     Patent Literature 
     
         
         Patent Literature 1: Japanese Patent Laid-Open No. 2002-035002 
       
    
     SUMMARY OF INVENTION 
     Technical Problem 
     However, in a case where the frequency of the tool is turned to the resonance frequency of the tool, there is a problem in that heat generated by the tool also becomes high. 
     The present invention is implemented in consideration of the point and has an object to provide a method for vibrating a handpiece-type high-frequency vibration apparatus, which facilitates cutting while suppressing heat increase in a tool. 
     Solution to Problem 
     A method for vibrating a handpiece-type high-frequency vibration apparatus of the present invention is the method for vibrating a handpiece-type high-frequency vibration apparatus which includes a handpiece including a vibrating body that ultrasonically vibrates, and which is capable of attaching two or more kinds of tools to a distal end portion of the handpiece and vibrates the tool by the vibrating body, the method comprising: a vibrating step of vibrating the tool, in a non-contact state where the tool is not in contact with an object, at an added frequency in which a predetermined frequency is added to a resonance frequency of the tool in the non-contact state; and a cutting step of driving the vibrating body, in a cutting state of cutting the object by the tool, such that the resonance frequency of the tool in the cutting state increases and approaches the added frequency. 
     According to the present invention, since the frequency of the tool is turned to the added frequency for which the predetermined frequency is added to the resonance frequency in the non-contact state before the tool cuts the object, compared to the apparatus for which the frequency of the tool is the resonance frequency, cutting energy becomes low and heat generation of the tool in the non-contact state can be suppressed. 
     Further, since the vibrating body is driven such that the resonance frequency of the tool increases and approaches the added frequency in the cutting state of cutting the object by the tool, cutting is facilitated. 
     In addition, it is preferable that the predetermined frequency be variable according to the tool. 
     According to the configuration, the tool can be vibrated at an appropriate frequency according to the tool. 
     Further, it is preferable that the predetermined frequency be selectable. 
     According to the configuration, the frequency of the tool can be set by an operator. Thus, for example, the operator with strong force of pressing the tool to the object when cutting makes the predetermined frequency higher than a threshold and the operator with weak force of pressing the tool to the object when cutting makes the predetermined frequency lower than the threshold, so that the appropriate frequency for facilitating cutting according to a type of the operator can be attained. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is an explanatory diagram relating to a configuration of a handpiece-type high-frequency vibration apparatus as one embodiment of the present invention. 
         FIG. 2  is a graph illustrating cutting energy according to a frequency of a tool in a non-contact state, a contact state and a cutting state. 
     
    
    
     DESCRIPTION OF EMBODIMENT 
     Hereinafter, the embodiment of the present invention will be described with reference to the drawings. 
     As illustrated in  FIG. 1 , a handpiece-type high-frequency vibration apparatus as one embodiment of the present invention comprises a roughly cylindrical housing  10  configuring a handpiece, a holding member  11 , a tool  12 , a controller  20  and an excitation device  21 . 
     The housing  10  is designed in a size to be held in one hand by an ordinary person. The handpiece of a high-frequency vibration-type cutting device is configured by components such as the housing  10  and the holding member  11  at least partially arranged in the internal space, and kinds and specifications of the components may be appropriately selected from a viewpoint of reducing weight of the handpiece for handling convenience. 
     The holding member  11  is attached to the excitation device  21  at the rear end portion, and is supported freely movably in an axial direction to the housing  10  via support portions  112  and  114  fixed to an inner side wall of the housing  10 . The holding member  11  has a function as a horn which increases amplitude. The tool  12  is freely detachably attached to a distal end portion of the holding member  11 . 
     A length of the tool  12  in a direction perpendicular to the axial direction of the holding member  11  is 30-150 [mm]. Examples of the kind of the tool  12  are a curette, a chisel, a surgical knife, a file, a long type and a short type. In addition, as a shape of the tool  12 , an arbitrary shape such as a blade with a straight or circular arcuate distal end, a roughly columnar shape, a spoon shape, or a bent or curved rod shape is adopted. 
     The excitation device  21  is attached to an attaching portion  10   a  of the housing  10 , is configured by a piezoelectric element arranged in the internal space of the housing  10 , and vibrates or reciprocatingly drives the holding member  11  in the axial direction. Electric power is supplied to the excitation device  21  via a cable  24  attached to the rear end portion of the housing  10  and the controller  20  and a conducting wire arranged in the internal space of the housing  10 . 
     Since the excitation device  21  and the holding member  11  are arranged such that respective axes are in common and separated in relation to the respective axial directions, compared to a case where the axes are separated in parallel or arranged in non-parallel, an occupancy space of the excitation device  21  and the holding member  11  in the internal space of the housing  10 , and eventually the housing  10 , can be made compact in relation to the direction perpendicular to the axes. Thus, the high-frequency vibration-type cutting device can be configured as the handpiece for which holding comfortableness and operability are improved. 
     Since force of the excitation device  21  is directly transmitted to the holding member  11  without use of a transmission mechanism, need of lubricant such as grease generally used for the transmission mechanism is eliminated Thus, in the case where the high-frequency vibration-type cutting device as a medical appliance is sterilized by high-pressure steam, a situation where contamination of the medical appliance resulting from presence of the lubricant occurs is avoided. 
     The controller  20  controls an operation of the excitation device  21 . A microcomputer or a processor configuring the controller  20  is arranged in the internal space of the housing  10  together with a substrate on which the microcomputer or the processor is mounted. The controller  20  performs control so that a vibration frequency f 2  in the axial direction of the tool  12  via the holding member  11  by the excitation device  21  is included in a range of 20-60 [kHz]. It is more preferable that the control be performed to be f 2 =25-45 [kHz]. 
     According to the handpiece-type high-frequency vibration apparatus of the configuration described above, by the holding member  11  being reciprocatingly driven in the axial direction, the object is cut by the tool  12  provided on the distal end portion of the holding member  11 . 
     Effects 
     In the case of cutting the object using the handpiece-type high-frequency vibration apparatus, an operator who performs cutting (surgery) attaches the tool  12  to the distal end portion of the holding member  11 . Then, the operator vibrates the holding member  11  (the tool  12 ) in the axial direction before cutting tissue, a bone in an ear, for example, of a patient as the object by the tool  12  (a non-contact state). 
     The controller  20  detects a first resonance frequency fr 1  of the tool  12  in the non-contact state by a detector (not illustrated). Then, the controller  20  drives the excitation device  21  so as to vibrate the tool  12  at an added frequency fp for which a predetermined frequency fs (to be described later in detail) is added to the first resonance frequency fr 1  (energizes a pulse current corresponding to the added frequency fp to the excitation device  21 ) (a vibrating step). 
     Thus, as illustrated by a dotted line in  FIG. 2 , since the tool  12  is vibrated at the added frequency fp higher than the first resonance frequency fr 1  in the non-contact state, in the case where the tool  12  is vibrated at the first resonance frequency fr 1 , a difference from a resonance frequency is generated, so that vibrating energy becomes low and heat quantity generated by the tool  12  can be reduced. Thus, in the case where the tool  12  is brought into contact with biological tissues (the biological tissues in the ear) around the object, deterioration or damage of the biological tissues is suppressed. 
     When the tool  12  is brought into contact with the object (a contact state), as a load applied to the tool  12  increases, a second resonance frequency fr 2  of the tool  12  in the contact state increases and approaches the added frequency fp. That is, since the difference from the resonance frequency of the tool  12  is reduced, the vibrating energy increases. 
     In a cutting state where the tool  12  is in contact with the object by the load that enables cutting of the object by the tool  12 , the controller  20  controls drive of the excitation device  21  such that a third resonance frequency fr 3  of the tool  12  in the cutting state increases and coincides with the added frequency fp (a cutting step). Also in the cutting state, the tool  12  is vibrated at the added frequency fp. In the present embodiment, for the predetermined frequency fs, a frequency that enables the third resonance frequency fr 3  to coincide with the added frequency fp is set. Without being limited to the coincidence, the third resonance frequency fr 3  may be made to approach the added frequency fp. 
     Thus, as illustrated by a solid line in  FIG. 2 , in the cutting state, since the tool  12  can be vibrated at the third resonance frequency fr 3  (added frequency fp), the object can be cut with high cutting energy without causing vibration attenuation by the load to the tool  12  and cutting efficiency is high. 
     Note that the predetermined frequency fs may be settable by the operator. For example, the operator with strong force of pressing the tool  12  to the object when cutting makes the predetermined frequency fs higher than a threshold, and the operator with weak force of pressing the tool  12  to the object when cutting makes the predetermined frequency fs lower than the threshold. Thus, the appropriate predetermined frequency according to a type of the operator can be attained. 
     In the present embodiment, between the contact state and the cutting state, the drive of the excitation device  21  is controlled so as to increase the resonance frequency of the tool  12  according to increase of the load of the tool  12  in contact with the object. That is, the cutting energy increases according to the increase of the force (the force of pressing the tool  12  to the object) applied by the operator. 
     Conventionally, when a bone curette is used, for instance, as the tool  12 , a cutting amount of the bone (object) is controlled by force adjustment of the operator. In the present embodiment, since the cutting energy (oscillation power) increases according to the force adjustment applied by the operator, the force to be applied can be reduced while utilizing a past operator sensation, and delicate work can be supported without stress. 
     In addition, in the case of cutting the object (the bone) in water while securing an operating field using an endoscope, when the cutting energy of the tool  12  is high, since the water around the tool  12  is largely shaken and bone dust and soft tissues are shaken by a water current, a visual field of the endoscope is obstructed, however, according to the present embodiment, workability is improved since the cutting energy is suppressed until right before cutting the bone. 
     The ideal embodiment of the present invention has been described above, however, the present invention is not limited by such an embodiment, and appropriate modifications are possible without departing from the gist of the present invention. 
     For example, while the first resonance frequency fr 1  of the tool  12  in the non-contact state is detected by the detector in the embodiment described above, the first resonance frequency fr 1  of each of the two or more kinds of tools  12  may be stored in a memory (not illustrated) beforehand and the controller  20  may read the first resonance frequency fr 1  from the memory according to the kind of the tool  12  attached to the distal end portion of the holding member  11 . 
     In this case, the handpiece-type high-frequency vibration apparatus further comprises an input interface for making the operator input the kind of the tool  12 . The input interface is configured by a keyboard, touch panel-type button or an operation button or the like, for example. 
     REFERENCE SIGNS LIST 
       10  . . . Housing,  11  . . . Holding member,  12  . . . Tool,  20  . . . Controller,  21  . . . Excitation device