Ultrasonic surgical tool capable of vibrating in multiple modes and drive system that induces non-linear vibrations in tool tip

Abstract

To provide an ultrasonic surgical tool system with a tip capable of simultaneously vibrating in multiple modes.SOLUTION: The system includes a console capable of supplying a drive signal to the tip that includes multiple components. Each component has a frequency characteristic that is based in part on the equivalent current through the mechanical components of the tip. The frequency components are different from each other. Based on the application of the drive signal, the tip undergoes non-linear vibrations.SELECTED DRAWING: Figure 11

Description

[Technical Field]

[0001] This application relates generally to ultrasonically driven surgical handpieces. More particularly, The present invention relates to an ultrasonically driven handpiece having a plurality of vibration modes and a non- and a method for driving the handpiece to linearly oscillate. [Background technology]

[0002] Ultrasonic surgical instruments are useful in performing several medical and surgical procedures. Generally, ultrasonic surgical tools contain at least one piezoelectric driver. The tip is mechanically coupled to a driver, and the driver is disposed The distal end has a head. The head has a It is provided with features (often teeth) sized to perform a specific medical or surgical task. The ultrasonic tool system also includes a control console. When a drive signal is applied to the driver, the driver periodically expands and contracts. The expansion and contraction of the driver occurs within the tip, more specifically the head of the tip. When the tip moves in this way, it is considered to be vibrating. The vibrating head at the tip is used to perform specific surgical or medical tasks. For example, several tip heads are applied to the hard tissue. When this type of tip head vibrates, the teeth at the tip vibrate back and forth. The tip head is configured to saw or remove adjacent hard tissue. Some ultrasonic tools are designed to be applied to soft tissue, and some ultrasonic tools are designed to penetrate the tissue and surrounding area. The tip head removes the tissue by inducing cavitation in the body fluid. As a result of these vibrations, cavitation occurs. Small voids, or cavities, form within the tissue and surrounding fluid. Sinuses are small areas of extremely low pressure. This pressure difference is relatively large, causing the cell wall to burst. The cleft removes, or excises, the cells that make up the tissue.

[0003] Ultrasonic tip heads are often relatively small, with some heads measuring less than 1.0 cm. The ultrasonic tool essentially cuts the tissue adjacent to where the head is placed. Due to the relatively small surface area of ​​the head, ultrasonic handpieces are able to remove hard tissue. It has proven to be a useful tool for precise removal of both hard and soft tissue.

[0004] Most tips vibrate in a single mode when a drive signal is applied. Here, the vibration mode is understood to be the path along which the tip head moves. The majority of the tip is designed to vibrate linearly. This means that the head vibrates along a certain axis. This axis is the length from proximal to distal along the tip. Some tips vibrate, but the head twists and vibrates. This means that when the head is activated and enters a vibrating state, Another tip is designed to flex. This allows the longitudinal axis of the tip to bend back and forth when the tip is actuated. This means that as the tip bends or flexes, the tip head moves.

[0005] Problems can arise if the tip head vibrates only in the longitudinal direction. The movement of the tip head of this type frequently induces cavitation in the tissue along the tip shaft. This is because the tip is in contact with hard tissue very close to soft tissue that should not be removed. This can be problematic when used to remove bone. Types of soft tissue that should not be affected include both blood vessels and tissue that is part of the nervous system. This procedure may result in unwanted removal of this soft tissue, so This causes problems.

[0006] Tips are now available that reduce this undesirable cavitation. These tips are designed to vibrate in two modes: longitudinal and longitudinal. The tip also vibrates in a torsional manner around the longitudinal axis of the tip shaft. One such tip is currently being developed by Stryker Corporation (Kalamazoo, Michigan), assignee of the present application. The Long Micro Claw tip is commercially available from the company (located in Tokyo). The structure is based on the patent no. 6,955,680 "Coupling Vibration Ultrasonic Hand Piece" ", the contents of which are expressly incorporated herein by reference. It shall be.

[0007] When a drive signal is applied to the tip, which can vibrate in different modes, the tip head When driven, the rod undergoes a motion that is the sum of the vibration displacements. The head of the tip, which can vibrate freely, vibrates both longitudinally and rotationally at the same time. This motion at a point on the tip head is shown in Figure 1. As a result of these simultaneous vibrations, the tip head A point on the head moves back and forth along a portion of the spiral. The stator core extends proximally and distally along the longitudinal axis of the stator core and rotates about the longitudinal axis.

[0008] The advantage of vibrating the tip in this way is that the range of vibration of the tip shaft in the longitudinal direction is small. This also results in unwanted removal of tissue adjacent to the shaft. is reduced.

[0009] Although the ultrasonic tool systems described above are useful, they are not without drawbacks. The reason is that for this system to work, the two vibration modes must occur at the same frequency. This means that the tip is specifically designed to vibrate in this mode. This limits the size and shape of the tip. To perform specific tissue removal procedures, the present invention provides a tip that can be applied to the site. Furthermore, the tip must be designed to meet this requirement. In this case, the tip can be relatively expensive to manufacture.

[0010] Furthermore, when the tip head undergoes this type of movement, the individual teeth of the tip head rotate in a helical fashion. This motion spans an orbit that is typically less than 300 microns in length. In reality, the motion of a single tooth is along a line oblique to the longitudinal axis of the distal shaft. As each tooth cuts into the bone, it creates a groove oblique to this axis. As the head reciprocates, the tip encounters resistance that prevents movement of the head in any direction other than the direction of the groove. As each tooth moves within its groove, this resistance can be significant. , hindering the practitioner's ability to direct or position the tip in a desired direction.

[0011] Additionally, any cutting operation may result in the ablated material being in the vicinity of the cutting tool. It creates debris that can be used to remove tissue by ultrasonic surgical tools. This applies to situations where the teeth of an ultrasonic surgical tool move back and forth in a linear path of movement. When teeth move, debris tends to accumulate between them. This debris buildup can be a sign that the teeth are becoming more susceptible to tissue damage. This adversely affects the ability to penetrate and remove Summary of the Invention

[0012] The present invention relates to a new and useful ultrasonic surgical tool system. The system of the present invention includes a tip that vibrates in multiple modes during vibration. a drive system that applies a drive signal to the tip that moves the tip head along a nonlinear travel path; It further has a

[0013] The system of the present invention typically includes a drive system capable of providing superimposed drive signals. This superimposed drive signal is the sum of several different components. There is one component for each vibration mode. In many versions of the invention, each component is This frequency characteristic is at the target frequency of a specific vibration mode of the tip. , or a frequency in the vicinity thereof. Here, the vibration modes are longitudinal, torsional, or The vibration of the tip can be in a single plane in the direction of extension and contraction. The frequency characteristics of the vibration modes are different from each other. Alternatively, the vibration modes may occur simultaneously in two or more planes. Here, the target frequency can be the frequency at which the tip will vibrate. Resonant and anti-resonant frequencies of the tip within the frequency range of the natural frequency range. The frequency is anywhere between the resonant frequency and the anti-resonant frequency of the tip, including

[0014] A further feature of the present invention is the ability to vary the characteristics of each component of the drive signal, i.e., frequency and voltage. During use of the ultrasonic tool, the tip head is subjected to resistance, i.e., mechanical load. This load changes the equivalent impedance of the mechanical elements of the handpiece. This characteristic change in the handpiece occurs in response to the application of a drive signal. This changes how the tip head moves or vibrates. To ensure that the motion desired by the subject is engaged, the system of the present invention generates a drive signal This adjustment of the drive signal is performed by adjusting the characteristics of the components of the drive signal. will be done.

[0015] The above features and advantages of the invention and the invention itself are set forth with particularity in the appended claims. Other features and advantages will be better understood from the following detailed description taken in conjunction with the accompanying drawings. will be done. [Brief explanation of the drawings]

[0016] [Figure 1] 1A and 1B illustrate the oscillatory motion of a tip head operating using a prior art system. [Figure 2] 1 illustrates the basic elements of an ultrasonic tool system incorporating the features of the present invention. [Figure 3]FIG. 1 is a schematic exploded view of the mechanical elements of the tool, namely the handpiece, tip and sleeve of the system. [Figure 4] FIG. 2 is a block diagram showing the electrical components of the handpiece and tip and how they are connected to the control console. [Figure 5] FIG. 10 is a diagram illustrating the types of data stored in memory within the handpiece. [Figure 6] FIG. 10 illustrates the types of data stored in memory integrated with the tool tip. [Figure 7] FIG. 2 is a block diagram of the electrical elements of the control console and handpiece components of the system of the present invention. [Figure 8] FIG. 4 illustrates the waveform of a drive signal applied to a handpiece in accordance with the system of the present invention. [Figure 9A.9B] Figure 9A shows the current flowing through the handpiece, and Figure 9B shows the impedance of different elements of the handpiece. [Figure 10A] 10B, 10C and 10D are flowcharts illustrating the operation of the system of the present invention. [Figure 10B] 10A, 10C and 10D are flowcharts illustrating the operation of the system of the present invention. [Figure 10C] 10A, 10B and 10D are flowcharts illustrating the operation of the system of the present invention. [Figure 10D] 10A, 10B, and 10C are flowcharts illustrating the operation of the system of the present invention. [Figure 11] FIG. 10 is a diagram illustrating the movement of a single point on the head of an ultrasonic tip as the tip is actuated, in accordance with the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0017] [I. System Overview and Hardware] 2 and 3, an ultrasonic tool system 30 incorporating the features of the present invention is shown. The system 30 includes a handpiece 32. The tip 142 is The handpiece 32 is attached to the base 32 and extends distally forward from the handpiece 32. ("Distal" means toward the area where the handpiece is applied, away from the practitioner.) "Proximal" means that the practitioner holding the handpiece is This is understood to mean that the handpiece is away from the patient, i.e., away from the area where the handpiece is applied. The tip 142 is applied to tissue to perform the desired medical or surgical procedure. The system 30 also includes a control console 240. The control console 240 provides the drive signals that are applied to the handpiece 32. In response to application of the signal, the handpiece 32 vibrates the tip 142 .

[0018] The handpiece 32 includes a body or shell 34, which is shown only in Figure 2. Within the shell 34 are disposed one or more vibrating piezoelectric drivers 36 (four are shown). Each driver 36 expands instantaneously when a current is applied to the driver. These expansions and contractions are caused by the longitudinal direction of the driver 36. The force occurs on a directional axis that extends between the proximal and distal faces of the driver. A pair of leads 38 extend away from each driver 36. The leads 38 The stent is attached to the opposing proximal and distal surfaces of the stent. The handpiece 32 includes a disk-shaped driver 36. The driver 36 has abutted ends. The leads 38 are connected together in a single stack. The elements of the system 30 that are applied to the inverter 36 are the insulating disks 40, one of which is shown. 2, the driver 36 and the insulating disk 40 are disposed between adjacent drivers. are shown spaced apart from each other. This is for ease of illustrating the elements. In reality, the driver 36 and the insulating disk 40 are in contact with each other without any gap.

[0019] Posts 44 extend longitudinally through driver 36, leads 38 and insulating disk. The post 44 passes through the driver 36, the lead 38 and the insulating disk 40. The driver 36, the lead 38, and the lead 39 extend along the longitudinal axis of the elements. The through holes in the insulating disk are not visible, but the posts 44 extend through them. The post 44 is connected to the proximal-most driver 36 and the distal-most driver 36. They protrude outward from both sides of the driver.

[0020] A proximal end mass 46 is located on the proximal side of the proximal-most driver 36. The mass 46 is attached to the proximal end portion of the post 44. If the post 44 is threaded, the mass 36 can be a nut.

[0021] Horn 48, shown only in FIG. 3, is located distal to the most distal driver 36. The horn 48 has a diameter approximately equal to the diameter of the driver 36. Extending distally and forward from the driver 36, the horn 48 The exposed distal end face of post 44 is secured to horn 48. In many versions, the post 44 and horn 48 are a one-piece molded unit. The piece 32 includes a driver 36 and a stack of insulating discs connected to the proximal end mass 36 and horn 48. It is configured to be compressed between

[0022] Also located within the handpiece shell 34 is a handpiece memory 56. 6 contains data used to control the operation of handpiece 32 and tip 142. The memory 56 can be in the form of an EPROM, EEPROM, or RFID tag. The structure of the memory is not part of the present invention. For purposes of illustration, the handpiece memory 56 may be an RF The coil 54 is connected to a memory 56. The coil 54 is connected to a control The console 240 reads and writes from and to the handpiece memory 56. , are elements associated with the handpiece.

[0023] Figure 5 shows the types of data stored in handpiece memory 56. These data contains data identifying the handpiece 32, as represented by field 62. These data verify that the console 240 is able to apply a drive signal to the handpiece. The data in field 62 is useful for verifying the You can also indicate the type of information about the handpiece that is presented in the handpiece notes. Other data in library 56 is used to control the supply of drive signals to driver 36. The use of these data will be explained later, but for now, the types of data will be explained. The capacitance C O , i.e., the capacitance of the stack of drivers 36 is The driver capacitance is analyzed during the assembly process of the handpiece 34. In most cases, the sum of the driver capacitances is 50 The field 66 indicates the voltage to be applied to the handpiece 36. Current, which is data on maximum current

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[0024] The handpiece memory 56 also stores the most recent drive signal to be applied to the handpiece 32. Data indicating the minimum and maximum frequencies are also stored. The wave number is usually the minimum frequency of the drive signal that can be supplied by the control console. The maximum frequency of the drive signal stored in field 74 is usually 5 kHz to 100 kHz below the minimum frequency. 40kHzHz high.

[0025] Field 76 is used to filter the control signal output from controller 96. The PID control loop is used to determine the final level of each of these signals. Field 76 contains the coefficients for each of these control loops. The data in 62, 66, 68, 70, 72, 74 and 76 are the data in field 64 Similarly, the handpiece memory 56 stores the I want you to understand that.

[0026] Handpiece memory 56 also includes field 78 as a usage history field. The control console 240 provides a log of the operation of the handpiece 32 while it is in use. To do this, write data into field 128.

[0027] Returning to FIG. 4, it can be seen that within the handpiece 32, two conductors 132 are also shown. Conductor 132 extends from coil 54 to the distal end of the handpiece. 32 is connected to a second coil, coil 134, also located within handpiece 32. will be done.

[0028] The tip 142 extends forward from the handpiece horn 48. The tip 142 The generally cylindrical shaft 144. Some, but not all, of the present invention In John, shaft 144 has multiple sections, each with a different cross-sectional diameter. In the illustrated version of the invention, the distal shaft 144 has a proximal portion 146. The proximal shaft portion 146 has a tip and a handpiece 32 that can be removably coupled to the tip. In one version of the invention, a coupling mechanism is formed that is designed to facilitate The handpiece coupling mechanism is a boss 49 extending forward from the horn 48 . The boss 49 has a threaded outer surface (not shown). A closed-end bore 144 extends inwardly from the proximal end of shaft 144 partially through distal portion 145. 45. The hole 145 has a threaded boss that is integral with the handpiece horn 48. The screw is provided with threads (not shown) designed to engage with the screw.

[0029] In the illustrated version of the invention, shaft 144 extends from shaft proximal portion 146 to The proximal portion 146 has a forwardly extending central portion 150. The central portion 150 has a diameter smaller than that of the proximal portion 146. The illustrated shaft 144 has a distal portion 156. Portion 156 has a diameter smaller than the diameter of central portion 150 .

[0030] The head 158 is the most distal portion of the tip 142. The head 158 is located proximal to the shaft. The head 158 is located adjacent and forward of the lower portion 156. The head 158 may have teeth or grooves. The distal head 158 is assembled to perform the desired procedure. The teeth or grooves are the part of the system 30 that is pressed against the weave. These teeth or grooves are designed to press against the tissue. The teeth or grooves remove the tissue. The geometry of the tip teeth or grooves is not part of the present invention.

[0031] The handpiece 32 as a whole generates a similar vibration in the tip 142 as the driver reciprocates. along the longitudinal axis of the tip, more specifically, the shaft These reciprocating motions are longitudinal vibrations in that they move back and forth along the shaft. The tip of the invention is provided with at least one shaft that is adapted to receive proximal to distal vibrations applied to the proximal end of the shaft. A mechanism for converting the vibration into two different types is also provided. These features include a spiral groove 150 extending inward from the outer surface of the shaft central portion 150. 2. The presence of groove 152 reduces the longitudinal motion applied to the proximal shaft portion. The tip of the groove is vibrated in the longitudinal direction as well as in the rotational direction. The rotational oscillation causes the shaft 144 to rotate in an arc extending about the longitudinal axis of the shaft. This should be understood to mean that the tip and the shaft vibrate.

[0032] The tip 142 incorporated into the system 30 of the present invention has resonant frequencies for multiple vibration modes. In many cases, these resonant frequencies are different from each other. The interval is 200Hz to 2000Hz.

[0033] The sleeve 170 is disposed around the distal shaft 144. The sleeve 170 is The proximal end of the sleeve is formed from a material that allows the sleeve to be attached to the distal end of the handpiece horn 48. A mechanism is provided to facilitate detachable coupling to the distal end of the system. The sleeve is radially spaced from the distal shaft 144 and from the distal head 160. More specifically, the elements are formed to be spaced apart longitudinally. The tip is dimensioned so that it does not contact the sleeve during operation.

[0034] Although not part of the present invention, sleeve 170 often includes a fitting 17 2 is formed. A connecting piece 172 is provided to receive the irrigation line. During use of the system 30, irrigation fluid often enters the sleeve 170. The fluid is forced into the gap between the tip 142 and the sleeve 170. The fluid flows through the handpiece post 44 and exits the open distal end of the sleeve. A series of holes are created in the suction tube (holes not shown). During the procedure, suction is passed through these holes. The suction draws irrigation fluid and the procedure fluid from the area where the tip head 158 is placed. The debris mixed with the fluid is sucked out. The tissue is sucked out toward the tip head 158. This facilitates the cutting of tissue by the tip head.

[0035] Disposed within the sleeve is a tip memory, shown as a dashed rectangle in FIG. 184. Although the memory 184 is located within the sleeve 170, The memory is called tip memory because it is used to control the operation of tip 142. Additionally, the tip 142 and sleeve 170 are typically distributed together in a single package. The tip 142 is typically first coupled to the handpiece 32. After the tip is positioned at this position, the sleeve 170 is fitted onto the handpiece. 184 is typically the same type of memory as handpiece memory 56. In the illustrated version, tip memory 184 is an RFID tag. 70, a coil 182, shown only in FIG. 4, is connected to the input pin of the tip memory 172. The elements forming the system 30 include a sleeve 170 connected to the handpiece 32. When engaged, handpiece coil 134 and coil 182 are inductively coupled to each other. It is designed to allow for involvement.

[0036] FIG. 6 shows the types of data contained within tip memory 184. These data include the tip identification field, as represented by The data in field 188 identifies the tip and stores the handpiece identification information field in the handpiece memory. This is similar to the data identifying the handpiece in field 112. Field 190 contains , the maximum equivalent current flowing through the mechanical elements of the handpiece,

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[0037] Field 206 contains data defining the minimum frequency of the second component of the drive signal. Field 208 contains data that defines the maximum frequency of the second component of the drive signal. The field 210 is connected to a target frequency ω for the second component of the drive signal. TRGT2 Data that defines Field 212 is used to associate a target frequency for the second component of the drive signal. The virtual impedance coefficient m2 is used.

[0038] The PID coefficient field 216 stores the PID coefficient field in the handpiece memory for the tip. Contains filtering coefficients for control signals that may be more detailed than the data in field 76. The tip memory 184 also includes a tip usage history field 218. During operation of the tip 142 control console 240 sets the field 218 Write data to.

[0039] Next, the control console 240 described with respect to FIGS. 2, 4 and 7 is 32, which causes the tip 142 to vibrate. The power supply 242 normally outputs a constant voltage signal of DC 1V to DC 250V. In many versions of the Ming, the maximum potential of the voltage output from the power supply 242 is 150 DC. The voltage generated by the power supply 242 is applied to a variable gain amplifier 244. A control signal, specifically a WAVEFORM_SET (W_S) signal, is applied to the amplifier 244. The WAVEFORM_SET signal adjusts the gain of the signal produced by the amplifier. In many versions of the invention, amplifier 244 defines WAVEFORM_SE This is a variable gain class A amplifier that can output an AC signal according to a T signal. In other words, the amplifier 244 outputs a signal having a frequency of 10 kHz to 100 kHz. In many cases, the signal has a minimum frequency of 20 kHz.

[0040] The output signal from amplifier 244 is fed to transformer 2, which is also part of control console 240. The voltage present across the secondary winding 258 of the transformer 248 is applied to the primary winding 254 of the transformer 248. The voltage is the drive signal applied to the handpiece driver 36. This voltage is typically up to The drive signal is applied in parallel across the driver 36. .

[0041] The transformer 248 includes a tickler coil 256. The voltage present at the regenerative coil 256 is applied to a voltage measurement circuit 262. Based on this, the circuit 262 generates a voltage V S , i.e., the drive signal applied to the handpiece 32 Also located within the control console 72 is a signal representative of the potential and phase of the voltage of the The coil 264 is in close proximity to one of the conductors extending from the secondary winding 258 of the transformer. The signal across the coil 264 is applied to a current measurement circuit 266. 66 is the current i S , i.e., the magnitude and phase of the current of the drive signal flowing through the handpiece Generate a signal representing

[0042] The drive signal present across the transformer secondary winding 258 is integrated into the control console. Two conductive contacts 266 are attached to a socket (socket not shown). It exists.

[0043] The drive signal is transmitted to the handpiece driver by cable 230, which is only visible in FIG. In many configurations of the system 30, the handpiece 30 and the cable 23 0 is a single unit. The cable 230 is connected to the control console where the contacts 266 are located. It is connected to a port socket.

[0044] In versions of the invention where the handpiece 32 and cable 230 are a single unit, The handpiece coil 54 is located in a plug that is integrated with the cable. The complementary coil 268 is placed in the cable socket. When the plug integral with 30 is inserted into the handpiece socket, coils 54 and 2 68 are configured to be able to exchange signals by inductive action.

[0045] Drive signal voltage V S and current i S is provided to the handpiece driver 36, The signal is also applied to a processor 276 located within the control console 240. The socket 240 also includes a memory reader 272. The memory reader 272 has one end connected to a The other end is connected to the source coil 268 and the other end is connected to the processor 276. 72 allows the signal present across the coil 268 to be read by a processor 272. The memory reader 272 also converts the data output from the processor 272 into a data signal. In response to the signal, the coil outputs a signal to the coil 268, which causes the coil to generate a signal and the data is written to the handpiece memory 56 and the tip memory 184. The memory reader 268 structure is complementary to the handpiece memory 102. Therefore, the memory reader can read data stored in the EPROM or EEPROM. It can be an assembly (means, functional part, part, device) that can be or an assembly that can interrogate the RFID and read data from it. It can be said that:

[0046] Processor 272 generates the WAVEFORM_SET signal that is applied to amplifier 244. In this manner, the processor 276 receives the output from the control console 240 and Sets the characteristics of the drive signal applied to handpiece 32. Set by processor 276 The drive signal characteristics to be used are the voltage and frequency of the drive signal. The characteristics of the protrusion 134 are determined according to the characteristics of the handpiece 32 and the characteristics of the distal end 134. The processor 96 operates at a voltage V S and current i S Determine the drive signal depending on the acquired measurement value of do.

[0047] The display 278 is integrated into the control console 240. The image on display 27 is shown as generated by processor 276. The information displayed on the handpiece 32 includes information identifying the handpiece 32 and tip, as well as information identifying the system The display 278 often includes information describing the operating state characteristics of the device. The processor 272 displays images of buttons on the display. By pressing these buttons, the practitioner can select the specific features of the system 30. You can set the desired behavioral characteristics.

[0048] In addition to the buttons presented on the display 278, there are also buttons typically associated with the control console. There is at least one on / off switch. The on-off switch is represented by a foot switch 280. The switch is configured to generate a signal that changes depending on how much the switch is pressed. The signal provided by the foot switch 280 is fed to the processor 280. Based on the state of the tip, the processor 276 determines whether the tip vibrates and the vibration of the tip head. The generation of the drive signal is adjusted to control both the magnitude of

[0049] [II. Basics of movement] The system 30 of the present invention is configured such that the control console 240, as a result of which the tip head 158 is not to output a drive signal that will move along a path of motion that can be considered linear. For purposes of the present invention, a non-linear travel path is defined as a path in which the tip head 158 oscillates back and forth. When moving, the movement of a single point on the head appears to be along two different sets of points in space. The tip head moves outbound in a single motion cycle relative to the starting point. When engaged in the outbound phase, the tip head travels along the first set of points. The inbound phase of the same cycle is when the leading head returns to the starting point. When engaging the tip head, the tip head travels along a second set of points that is different from the first set of points. Furthermore, the set of points that the tip head travels through during the first complete vibration cycle is determined by the set of points that the tip head travels through during the next vibration cycle. During the vibration cycle, the set of points traveled by the tip head may differ from the set of points traveled by the tip head in the circle. The set of points along which the end head travels may not lie in a single plane. It should be understood that a set of points may lie in multiple planes. The set can be rotated around one or more axes.

[0050] FIG. 8 shows how the control console 240 controls the hand to induce the above-described movement of the tip head 158. 1 shows the waveform of the drive signal output to the handpiece driver 36. The drive signal is the sum of two AC signals, called components. Each drive signal component has its own frequency and its own These different components usually have different frequencies. The potentials of the different components of the signal differ from each other.

[0051] A further feature of many versions of the invention is that each component of the drive signal induces a particular vibration of the tip. The frequency is at or near the target frequency of the vibration mode. The mode is vibration of the tip in a single plane, either longitudinal, torsional or extensional. Here, vibration in the longitudinal plane is oriented along the longitudinal axis of the tip 142. It should be understood that the vibration in the torsional plane is a reciprocating motion along the tip head. It is understood that the rotational reciprocating motion of the tip head 158 in a plane perpendicular to the longitudinal axis of the The bending motion is the reciprocating motion of the tip head in the plane in which the longitudinal axis of the tip is located. Therefore, the bending motion is a deflection of the tip around the shaft 144. This bending motion is , may occur in any direction 360 degrees around the shaft. The vibration mode of the portion 42 may be a vibration that is a simultaneous reciprocating motion of the tip in two planes. For example, one vibration mode may be one in which the movement of the tip shaft The longitudinal and torsional directions are along a first line that intersects the longitudinal axis of the The second mode can be a second combined longitudinal mode along a line. and torsional motion. The difference between these two vibration modes is the second The vibration of the first mode is along a line that is different from the line of vibration of the first mode.

[0052] The "target frequency" for a vibration mode according to the present invention is the frequency range at which tip 142 vibrates. The target frequency is usually the resonant frequency for the vibration mode, The anti-resonance frequency for the The resonance frequencies of the vibration modes of the tip are different from each other, so the target frequencies of the vibration modes are also different. Please understand that these are different.

[0053] In many versions of the invention, the potential of each component of the drive signal is The end 142 is provided with a mechanical element that facilitates the flow of a target equivalent current through what is known as the mechanical element. These elements include the driver 36, the post 44, and the proximal It includes the end mass 46, the horn 48, and the tip 152. The sleeve 170 is typically This is because when the sleeve 170 vibrates, the vibration of the sleeve This is because the vibration is caused by the vibration of other elements. , we will simply call it the equivalent current flowing through the mechanical elements of the handpiece. This phrase is Even though the shell 170 can be considered a mechanical element of the handpiece 32, It will be used.

[0054] FIG. 9A shows the drive signal current i S is a schematic diagram showing how it is separated into two components. The first component is the current i O , i.e., the current through the handpiece driver 36 is The second component is the current i M is the equivalent current flowing through the mechanical elements of the handpiece. According to Ohm's law, the current flowing through the driver and the mechanical components of the handpiece The equivalent current flowing through the element is the drive signal voltage V S and the impedance of these elements. In FIG. 9A, Z O is the impedance of the handpiece driver 36. Peedance Z M is the equivalent reactance of the mechanical elements of the handpiece.

[0055] The impedance of the driver 36 is primarily due to its capacitive reactance. Therefore, in the schematic diagram of FIG. 9B, the driver impedance Z O is simply a driver capacitor ance C O For the purposes of the system 30 of the present invention, the driver's capacities are expressed as a function of Persistence C Ois approximately constant. The equivalent impedance of the mechanical elements of the handpiece is It has a resistance component, an inductive reactance component, and a resistance component. Therefore, in FIG. , mechanical equivalent impedance Z M is the resistance R M , capacitance C M and inductance L M In Figure 9B, the mechanical equivalent resistance R M , equivalent capacitance C M and equivalent inductance L M is shown as variable. This means that The properties of the tip 142 change depending on the mechanical resistance that the tip 142 is exposed to when the tip is applied to tissue. This is because.

[0056] At any one time, the equivalent current flowing through the mechanical elements of the handpiece is calculated based on the following formula: It is required based on the

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[0057] As previously mentioned, the system 30 of the present invention is configured such that each component of the drive signal is controlled by the function of the handpiece. Control the drive signal so that it is at a frequency that tracks the target frequency of the mechanical element as closely as possible. The device is further configured to control

[0058] Generally, the relationship between the frequency of the drive signal and the target frequency is determined by the frequency of the drive signal flowing through the handpiece driver 36. First, find the real component of the ratio of the current flowing through the handpiece to the equivalent current flowing through the mechanical elements of the handpiece. This ratio can be calculated by the following formula:

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[0059] The drive signal applied to the handpiece driver of the present invention is composed of multiple components. So the ratio for a single component is:

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[0060] This ratio is compared to a constant target ratio (TR). The target ratio is usually set to 0 and It is a number between 0 and 1, including 1. The aim is to ensure that the component of the drive signal is at the resonant frequency of the vibration mode. If the component of the drive signal is at the anti-resonance frequency of the vibration mode, the target ratio is 0. If the objective is to achieve a desired frequency of the drive signal component, the target ratio is 1. In an embodiment of the present invention, the drive frequency is between the resonant frequency and the anti-resonant frequency of the drive. The number is a fraction between 0 and 1.

[0061] When comparing the ratio of Equation (2A) with the target ratio, it is not enough to simply compare the frequency of the drive signal component with the desired There may be situations where the frequency does not provide a good degree of correlation with the desired target frequency. This may occur as a result of the placement of the tip head 158 relative to the tissue. The unique features of some tip heads allow the tip heads to be positioned to strike the tissue and reduce the load. When the frequency is applied, the mechanical elements of the handpiece Furthermore, sometimes the practitioner may Before actuating the handpiece 32, it is desirable to position the distal head 158 so that it contacts the tissue. When this occurs, the resistance of the equivalent impedance of the mechanical elements of the handpiece The components are the capacitive and inductive reactances of this component of this impedance. In either of these situations, the ratio of Eq. (2A) The step described below involves changing the frequency of the drive signal components so that , does not lead to providing a drive signal having components at frequencies close to the target frequency. There are cases where this happens.

[0062] Thus, a component of the drive signal is adjusted to the target frequency for the vibration mode with which it is associated. To determine whether the frequency is close to the wavenumber, the following modified version of Eq. (2A) is used: Used.

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[0063] [III. Actual Operation] Operation of the system 30 of the present invention begins with coupling the tip 142 to the handpiece 32. A sleeve 170 is fitted over the tip and also attached to the handpiece 32. The cable 230 is attached to the control console 240. At that point, the console The module 240 is ready to be switched on. This constitutes the initial assembly and startup of the control console, i.e., step 302 of FIG. When the power switch 240 is first turned on, the processor 276 and reads the data stored in the handpiece memory 56 and tip memory 184. The processor 276 asserts the appropriate command to the memory reader 272. These data are received.

[0064] Based on the read data, in step 306, the processor Step 306 ensures that the system 30 is properly configured for use. This involves performing several evaluations to determine whether the The handpiece is a handpiece to which the control console 240 can provide a drive signal. and determining whether tip 142 is suitable for actuation by the handpiece. These evaluations include determining whether the tip is a genuine handpiece. The information field 62 and the tip identification information field 188 may be based on data. The processor 276 also processes the handpiece usage history field 78 and the tip usage history field 79. Based on the data read from field 218, handpiece 32 and tip 142 Evaluate whether the product is suitable for use. An example of data to be included is the data that a particular element, i.e., handpiece or tip, is using for that element. Data showing that the product has been used for a number of times or for a total period of time exceeding its design life. do.

[0065] Considering the elements are properly assembled for use as a system, processor 27 Processor 26 presents information regarding this achievement on display 278. 76 to ensure that the vibration of the tip head 158 is the movement desired by the practitioner. Prompts the practitioner to enter information indicating how the system should be configured to All of the above is part of step 306. Receiving the initial setup command from the practitioner is also part of step 306. It is part of 306.

[0066] The data in the handpiece memory 56 and the tip memory 184 and the data entered by the practitioner Based on the command, the processor 276 adjusts the components of the drive signal in step 308. The selected maximum equivalent current i flows through the mechanical elements of the handpiece per SELECTMA X-X This example of the operation of the system is based on the tip 142 of FIG. The tip 142 is configured such that the drive signal is transmitted to the tip in two planes, i.e., the longitudinal direction and the bending direction. The drive signal is designed to produce movement of the head 158. Therefore, the drive signal is made up of two components: That is, the first component is based on a target frequency associated with vibration in the longitudinal plane. The second component is based on a target frequency associated with vibration in the torsional plane. In step 308, the selected maximum equivalent current is calculated for each component of the drive signal using the following formula: It is defined as follows.

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[0067] In the described version of the invention, the drive signal has two components. In step 308, formula (3) is executed twice. The first time the formula is executed, The maximum equivalent current for the drive signal component of 1, i.e., the equivalent current of the maximum current field 192, flow

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[0068] Step 310 is when the processor determines that the practitioner wants to activate the handpiece, i.e., Whether the control has been activated to indicate that the tip head 158 is desired to vibrate In the described embodiment of the present invention, processor 2 76 monitors the signal output by the foot switch 280. When the practitioner wants to activate the tip, the practitioner presses the foot switch 280. The magnitude of vibration of the tip head is controlled by the practitioner when the foot switch 280 is pressed. It is set by controlling the degree.

[0069] The processor 276 receives a signal from the foot switch indicating that the switch has been pressed. When the processor receives the signal, it performs step 312. In step 312, processor 2 72 is the target equivalent current for each component of the drive signal

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[0070] When the console 240 first executes the control loop of FIGS. 10A-10D, i.e. , during the first execution of the loop after the evaluation result of step 310 is positive, processor 27 6 executes step 314. In step 314, initial characteristics of the components of the drive signal are generated. The frequency of each component is called the variable FREQ_COMP-X. The voltage of each component is Each component of the drive signal has an initial frequency and an initial The initial frequency of a component is determined by the initial potential, as read from the tip memory 158. If it is the first component, this is the lowest frequency in memory field 196. If it is the second component, it is the frequency contained in memory field 206. The initial potential is a potential that is less than the maximum potential of the component of the drive signal. In some aspects of the invention, the initial potential is the maximum potential for that component of the drive signal.

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[0071] Next, based on the characteristics of each component of the drive signal, the control console 240 proceeds to step 315 As part of step 315, processor 276 outputs a drive signal. The waveform will have the shape shown in Figure 8. The processor 276 generates a WAVEFORM_SET signal that represents this waveform. The WAVEFORM_SET signal is then applied to the input of amplifier 244, where the gain control signal is provided. is applied to

[0072] In response to receiving the WAVEFORM_SET signal, amplifier 244 The amplifier acts as a modulator to selectively amplify or attenuate the signal from the power supply 242. The transformer 248 is connected to the handheld terminal 252 through a cable 230. A drive signal is output to the piece driver 36. All of the above is part of step 315.

[0073] In response to a drive signal being applied to the handpiece driver 36, the driver periodically The expansion and contraction of the driver is proportional to the potential of the drive signal. , which is proportional to the amplitude of the drive signal and also to the frequency of the drive signal. The distal end 146 amplifies and transmits these expansions and contractions to the proximal portion 146. These vibrations The grooves 152 are aligned along the longitudinal plane of the shaft. These vibrations are converted into vibrations in the plane. The changing potential of these vibrations and the structure of the tip The rod 158 is made to oscillate, and its movement is non-linear as shown in FIG. In Figure 11, immediately to the right of the leftmost equal sign, this movement is shown as a single elliptical progression path. vinegar.

[0074] In the present invention, each component of the drive signal does not have the same frequency, so that two consecutive oscillations The path of travel of the cycle is not the same. As a result, the tip head is not linear and In addition, the single elliptical loop in Figure 11 is actually a closed loop. In Figure 11, the center plot to the right of the center equals sign indicates the path of a point on the tip head after the tip head has engaged in several vibration cycles In Figure 11, the plots to the right of the equal sign indicate that the tip head has undergone more vibration cycles. These plots show the path of the tip head point after engaging with the , a point on the tip head, i.e., a point on the tooth, subtends a surface. Although the surface in Figure 11 appears inherently curved, the surface may be curved around more than one axis. It should be understood that what is implied in this movement of the tip head point is a series of multiple This means that the direction of the path of the point changes during the vibration cycle of the number.

[0075] The system 30 continues to output drive signals to provide the desired movement of the tip head 158. To ensure that the system is operating at its optimum, a feedback control process is involved. To do this, in step 154, processor 272 executes the system The voltage V of the drive signal flowing through the handpiece is S This is the voltage measurement circuit The output signal generated by 262 is monitored by processor 272. As part of its monitoring, the processor monitors the voltage V S is divided into multiple components. Specifically, the voltage V S is divided into one component for each component that makes up the drive signal. Therefore, the drive signal has two components: voltage V S is the potential of the first component

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[0076] As part of the feedback control, in step 318, processor 272 The current i, which is the drive signal current flowing through the end piece S This monitoring is performed by the current measurement circuit. 266. Similar to the drive signal potential, the drive signal current is Therefore, as part of step 318, The processor converts the drive signal current into a first component characteristic current

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[0077] In step 320, the processor determines the equivalent current for each component of the drive signal. The equivalent current of is calculated rather than measured, so it is sometimes called the calculated equivalent current. In step 320, using equation (1A),

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[0078] calculation current

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[0079] Equation (1A) takes into account an additional variable in the handpiece driver 36, namely, the capacitance C 0. The processor 272 uses the handpiece memory field as this capacitance. The driver capacitance read from field 64 is used.

[0080] In step 322, the calculated equivalent current of the first component of the drive signal is If the equivalent current is less than the target equivalent current, the associated The vibrations in the dynamic mode must be of sufficient amplitude to promote the desired movement of the tip head 158. This comparison is made because it is highly unlikely that the mechanical elements of the handpiece will be exposed to equivalent If the current is greater than the target equivalent current, the tip head 158 will operate at a higher amplitude than the practitioner desires. There may be cases where vibrations of large amplitude are being experienced.

[0081] In some versions of the invention, if the calculated equivalent current is within 10% of the target current, In other words, the equivalent current applied to the mechanical parts of the handpiece promotes the desired vibration. Alternatively, if the two currents are within 5% of each other, ideally within 1%, the currents are sufficient. It's the size.

[0082] If the two equivalent currents are approximately equal, the system 30 controls the mechanical elements of the handpiece. The equivalent current that flows is determined by the application of the drive signal at the correct frequency and in the relevant vibration mode. The vibration level is assumed to be sufficient to cause vibration of an appropriate amplitude to the head 52. If system 30 is in this state, processor 96 proceeds to step 326.

[0083] In many cases, the comparison in step 322 is based on a calculated mechanical equivalent current.

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[0084] In step 326, processor 272 determines whether the frequency characteristic of the first component of the drive signal is Determine whether the frequency is at or approximately equal to the target frequency for that component of the drive signal. The cutoff is that the output of the drive signal causes the desired movement of the tip head as a result of the frequency characteristics of the first component. In step 326, the equation (2 This determination is made by comparing the ratio of B) to the target ratio. The variables used in step 318 to calculate the ratio are used to generate this ratio. The remaining variables used to generate this ratio are the target values ​​of the frequency components. , the variable ω in field 202 of tip memory 184 TARGET1 The coefficient m1 is The coefficient field 204 of the tip memory 184. The exponent A modifies the ratio. It is assumed to be constant and identical for all calculations that generate the (ratio modifier). It is within the scope of the present invention that A may vary.

[0085] In some cases, the frequency response may be adjusted to meet the target frequency response if the ratio is within 10% of the target ratio. In yet another version of the invention, if the ratio is within 5% of the target ratio, In some cases, more preferably within 1% of the target ratio, it is considered to be approximately equal.

[0086] The comparison in step 326 determines whether the frequency characteristics of the first component of the drive signal are greater than or equal to the frequency characteristics of that component of the drive signal. This may indicate that the drive signal is at or nearly at the target frequency. 40 expansion and contraction, resulting in the tip head moving in the desired pattern. When system 30 is in this state, processor 272 executes step Proceed to execute 330.

[0087] In step 326, the frequency characteristics of the first component of the drive signal are evaluated to determine whether the tip It is determined that a drive signal output that does not induce a desired pattern of head movement is occurring. If processor 272 makes this determination, then in step 328: The processor adjusts the frequency characteristic FREQ-COMP1 of the component of the drive signal. 2B) is negative, the calculation of step 164 which gives a negative result is At 328, a program is started that indicates that the frequency characteristic of the first component of the drive signal should be increased. If the calculation of step 326 produces a positive result, the If so, the processor 272 converts the results into the probability that the tip head will follow the desired travel path. In order to improve the performance, the handpiece needs to lower the frequency response of the first component. This is interpreted as indicating that

[0088] After performing step 326, or optionally after performing step 328, the processor Step 330 includes calculating the equivalent current of the second component of the drive signal and , and comparing this equivalent current with a target. Step 330 is substantially the same as step 322. The difference between step 322 and step 330 is that in step 330, the calculated

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[0089] If the two values ​​compared in step 330 are not substantially equal, then step At 332, the processor resets the voltage characteristic of the second component of the drive signal. The purpose of step 332 is to reset the voltage characteristic of the first component of the drive signal by performing step 324. As part of step 332, processor 272 , based on an arbitrary reset of the voltage characteristic of the second component of the drive signal, WAVEFORM_SE The T signal is reset, and the drive characteristics change accordingly.

[0090] After step 330 and, if necessary, step 332 are performed, step 3 At 34, the frequency characteristics of the second component of the drive signal are evaluated. The same process as that used in step 326 to estimate the frequency characteristics of the first component In step 334, the variable of the second component of the drive signal is calculated using the formula (2 In this use of equation (2B), the second component of the drive signal has the appropriate frequency response. In order to determine whether or not the ratio has a change component, the tip memory field 210 The target frequency ω TARGET2 is is used as the coefficient of the ratio change component. The coefficient m2 in the field 208 of the memory is used. In some cases, the frequency characteristics of the second component of System 3 are sufficiently equal to the target frequency. When 0 is in this state, the processor determines whether the control unit remains activated. To do so, return to step 310.

[0091] Alternatively, the evaluation in step 334 may be performed to determine whether the frequency characteristic of the second component of the drive signal is consistent with the target frequency. This may indicate that the system 30 is not in this state. At some point, processor 276 resets this frequency characteristic in step 336. .

[0092] After performing step 336, the processor returns to step 310. If the evaluation of step 310 indicates that the on-off switch remains activated, If so, step 312 is executed again. This step is important because the practitioner may enter a command indicating that the The loop is executed again.

[0093] Since the frequency characteristics and voltage characteristics of each component of the drive signal have already been set, the control rule In this execution of the group, step 314 is not performed. Instead, the previously generated Step 315 is executed again based on the set of drive signal component characteristics. If the characteristics of the drive signal components have changed since the last time Processor 276 generates a new WAVEFORM_SET signal. The rule then adjusts accordingly based on the adjustments calculated so far for the characteristics of each component of the drive signal. A new drive signal whose characteristics have been adjusted accordingly is output.

[0094] During subsequent executions of the control loop, the drive signal induces the desired movement of the tip head 158. In order to determine whether or not the reset timing of each component of the drive signal is correct, the variables ω1 and ω2 are used. It should be understood that the frequency characteristics are utilized.

[0095] There will inevitably be a point when the handpiece will stop. The practitioner will need to turn the on / off switch. In step 310, it is determined that this event has occurred. The processor 276 then controls other elements of the console 240 to control the drive to the handpiece. Assert a command to terminate application of the dynamic signal (this step is not shown).

[0096] Although not shown, the waveform_set signal is initialized and subsequently readjusted. In both cases, the processor 272 controls the drive signals to be transmitted to the handpiece memory 56 and the tip memory. This ensures that the data is limited by the boundary characteristics read from both the These limits are based on the maximum drive signal voltage in field 70 of the handpiece memory. and the first component of the drive signal based on the voltage data in field 191 of the tip memory. and a second determination of the drive signal based on the voltage characteristics of the tip and the voltage data in field 193 of the tip memory. component voltage characteristics and the optimum drive signal based on the data in field 66 of the handpiece memory. High current and maximum power consumption of the handpiece based on data in field 68 of the handpiece memory. The equivalent current and the first component of the drive signal based on the data in field 192 of the tip memory. and the second value of the drive signal based on the data in field 194 of the tip memory. This includes limiting the maximum equivalent current for the component.

[0097] The frequency characteristics of the drive signal are also stored in the handpiece memory 56 and the tip memory 184, respectively. In this way, the entire drive signal is set based on the data read out from the The data in fields 72 and 74 of the handpiece memory are used to define the boundaries of The frequency range data in fields 196 and 198 of the tip memory are Defines the frequency range of the frequency response of one component. Fields 206 and 208 of the tip memory The frequency range data defines the frequency range of the frequency characteristics of the first component of the drive signal.

[0098] As previously mentioned, the system 30 of the present invention performs a single oscillation cycle on the tip head. The tip head 158 is vibrated so that a point on the rod does not simply reciprocate along a line. Instead, the point is involved in a non-linear path. When the point on the head strikes the bone and moves, the teeth strike the bone and immediately afterwards grind against it. When the teeth strike the bone, they fracture the bone, leading to the removal of tissue. This removes the newly removed material from the bone. The time between when the bone is removed and when the removed tissue is removed is short. There is only a relatively small amount of debris in the hull. The extent to which the presence of these debris adversely affects the bone resection process is likewise reduced.

[0099] When the system of the present invention drives the teeth of the tip head in a nonlinear motion, In the case of a tooth, essentially the entire circumference of the tooth is pressed against the tissue to which the tip head is applied. This movement of the teeth against the tissue results in the desired tissue abrasion. In a single cycle of movement, essentially the entire surface of the tooth is pressed against the tissue. As the teeth are rotated, each surface is subject to at least some wear. Reduces the degree to which surfaces are subject to apparent uneven wear. Minimizes uneven wear on individual teeth. It is believed that by limiting the amount of tooth removal, the degree to which the tooth removal efficiency is reduced can be similarly reduced. In one procedure, the removal efficiency of the apical tooth set is reduced, resulting in unnecessary replacement of the apical part. This reduces the possibility of deterioration to a level that requires

[0100] Furthermore, essentially every tooth surface is pressed against the tissue during a single movement cycle. During the cycle, a single tooth surface is pressed against the tissue for a long period of time. This prevents the surface from constantly pressing against the tissue over time. This reduces the heating caused by friction on the tooth surface that could occur if the teeth were attached. Even if heat is unavoidably generated, the suppression of heat is to be carried out by limiting the heat generated in the assembly adjacent to the tip head. This reduces the potential for damage to the tissue surrounding the tissue.

[0101] The system 30 vibrates the tip in multiple vibration modes of different frequencies. It should be further understood that multiple tips can be used with this system. When the tip vibrates in the two modes, it vibrates at a common frequency. It is not limited to the vibrating tip. When vibrating in multiple modes, There are significant manufacturing constraints and costs associated with having to provide a vibrating tip. These constraints and costs are usually due to the fact that the system vibrates in multiple modes. This is irrelevant when providing a tip that vibrates at a frequency other than 100 Hz. The system 30 is capable of vibrating simultaneously in different modes, both in terms of manufacturing and economics. This increases the feasibility of providing different tips that can be used.

[0102] A further feature of the present invention is the ability for the practitioner to set a non-linear path for the tip head. More specifically, in response to the setting of this path by the practitioner, processor 276 performs the steps 308, the individual maximum equivalent currents i for each vibration mode SELECTMAX-X Set One current i SELECTMAX-X is set to be relatively large, and the second FlowSELECTMAX-X By setting to be relatively small, the result is The resulting drive signal is generated so that the tip undergoes a first vibration path during a single motion cycle of the tip head. The first vibration path is subjected to a relatively large motion, and the second vibration path is subjected to a relatively small motion. The current i related to the two vibration modes is SELECTMAX-X of By setting them to be approximately equal, the drive signals result in the tip moving in two different directions. motions that can undergo simultaneous motions that are more equal in terms of displacement in different vibration paths. This will result in the following.

[0103] Sometimes, practitioners may need to direct the distal end of the distal shaft to tissue at a large radial distance from the longitudinal axis of the distal shaft. In order to perform a procedure on tissue located in such a way, it may be necessary to apply the tip head to the tissue. , providing a tip with a head positioned asymmetrically relative to the longitudinal axis of the tip shaft This asymmetry inevitably causes the tip head to vibrate in multiple modes. Typically, these vibration modes are at different frequencies. By controlling the vibration in these multiple modes, when the tip head vibrates, , whose movement is along a path that is predictable and results in efficient removal of tissue. This will ensure that the system is up and running smoothly.

[0104] Furthermore, the tip head, which is placed into vibration in accordance with the present invention, moves in a non-linear pattern. Therefore, each tooth tends to push the excised tissue out of its path. Removing these debris from the tooth reduces the efficiency of tissue ablation in subsequent vibration cycles. Reduce the degree to which the value is reduced.

[0105] The above description relates to one version of the system of the present invention. Versions of may have different features than those described above. For example, Some tips of this system may have more than two vibration modes. In the case of a system configuration, the drive signal will have three or more components. It is further understood that the target frequency characteristics for some may be close to each other, even if they are not identical. Similarly, sometimes the equivalent current applied to the mechanical elements of the handpiece is For multiple components of a motion signal, the values ​​may be nearly, but not exactly, identical.

[0106] The structure of the elements of the system may differ from that which has been described. Some versions of the system have internal control units inside the console that operate simultaneously and independently of each other. There are multiple signal generators that operate the signal generators. The processor The processor adjusts the voltage and frequency of the signal generated. More specifically, the processor Each signal generator is controlled so that it outputs a specific component of the drive signal. The components are added together to generate the drive signal that is applied to the handpiece driver 36. can be.

[0107] In some versions of the invention, the assembly that provides the drive signal to the handpiece comprises: It may not include an amplifier that modifies the voltage applied to the console transformer. In these versions, the assembly that provides the signal on which the drive signal is based uses a variable current source. include.

[0108] Therefore, in an alternative version of the invention, the voltage of the drive signal applied to the handpiece The disclosed coil 256 and It should be understood that assemblies other than 264 may be utilized. In this version, one or more resistor networks are used to determine the voltage and current measurements. This can provide a signal on which the signal is based.

[0109] In all versions of the present invention, the driver capacitance is integral with the handpiece. The data does not have to be based on data read from the memory being encoded. In the , the processor outputs drive signals at various frequencies and measures the voltage and current of the drive signals. The capacitance of the driver is determined by measuring

[0110] In some versions of the invention, a processor identifies the resonant and anti-resonant modes for each vibration mode.

[0111] In some configurations of the present invention, the path of travel of a point on the tip head 158 is not intended or intended to be Although the path is nonlinear in its purpose, it is understood that it appears as a linear path. stomach.

[0112] In FIG. 11, the nonlinear path illustrated is considered to be an essentially elliptical path. It should be understood that this is an example and is not limiting. The path may have other shapes. These shapes include essentially circular and essentially crescent shapes. It is further within the scope of the present invention for non-linear paths to include paths that cross each other. The traditional shape of this type of pathway is a figure-eight pathway.

[0113] In some versions of the invention, the potential of one or more of the components of the drive signal is fixed. In these versions of the invention, the mechanical elements of the handpiece may be The equivalent current that is applied is controlled by adjusting the target frequency associated with that component.

[0114] Furthermore, the frequency characteristics of the drive signal components generally differ, but this is always the case. It should be understood that this may not always be the case. Depending on the type of load involved, the frequency characteristics of two or more components of the drive signal may be identical. be.

[0115] Therefore, it is the object of the appended claims to include all such modifications as come within the true spirit and scope of the invention. It is intended to encompass such modifications and variations.

Claims

1. 1. An assembly for vibrating a tip of an ultrasonic surgical tool, comprising: the ultrasonic surgical tool has at least one driver to which an AC drive signal is applied to vibrate the tip, the tip being configured to vibrate in a plurality of vibration modes; an assembly for generating a variable AC drive signal applied to the at least one driver of the ultrasonic surgical tool; Processor and Equipped with The processor: reading data indicative of at least one drive signal characteristic for each of the plurality of vibration modes from a memory associated with the tip; asserting a command to an assembly that generates the AC drive signal, causing the assembly to generate an AC drive signal that includes a component for each vibration mode, the component for each vibration mode being based on the at least one drive signal characteristic indicated by the data read for that vibration mode; assembly.

2. 2. The assembly of claim 1, wherein the at least one drive signal characteristic for each vibration mode indicated by the retrieved data comprises a voltage characteristic for that vibration mode.

3. 3. The assembly of claim 1 or 2, wherein the at least one drive signal characteristic for each vibration mode indicated by the retrieved data includes a frequency characteristic for that vibration mode.

4. The assembly of any one of claims 1 to 3, wherein the processor asserts the command to an assembly that generates the AC drive signal, and the AC drive signal including components of each vibration mode is applied to the at least one driver, causing the tip head to move in a loop.

5. The processor: receiving a movement path set by a surgeon for the distal head of the ultrasonic surgical tool; Based on the movement path set by the practitioner, a target current characteristic for each vibration mode is calculated, asserting the command to the AC drive signal generating assembly to adjust a component of the AC drive signal generated for each vibration mode based on the target current characteristic determined for that vibration mode, whereby the adjusted AC drive signal is applied to the at least one driver to move the tip head in a single vibration cycle along a path of movement set by the practitioner. Assembly according to any one of claims 1 to 4.

6. 6. The assembly of claim 1, wherein the at least one drive signal characteristic for each vibration mode indicated by the retrieved data comprises a maximum equivalent value of electrical current flowing through a mechanical component of the ultrasonic surgical tool for that vibration mode.

7. The processor: determining a target equivalent value of the current flowing through the mechanical component of the ultrasonic surgical tool for each vibration mode based on a command set by a surgeon and a maximum equivalent value of the current flowing through the mechanical component of the ultrasonic surgical tool for each vibration mode indicated by the read data; determining a voltage characteristic for each vibration mode based on the target equivalent value of current through the mechanical component of the ultrasonic surgical tool for that vibration mode; the processor asserts the command to an assembly that generates the AC drive signal, the component of each vibration mode of the AC drive signal being based on a voltage characteristic determined for that vibration mode; 7. The assembly of claim 6.

8. the operator-set command indicates a path of travel for the tip, and the processor determines the target equivalent value of current through the mechanical components of the ultrasonic surgical tool for each vibration mode, whereby the AC drive signal including a component for each vibration mode is applied to the at least one driver, causing the tip head to move in a single vibration cycle along the indicated path of travel.

8. The assembly of claim 7.

9. The processor: determining a coefficient for each vibration mode based on a command set by the practitioner; determining the target equivalent value of the current flowing through the mechanical component of the ultrasonic surgical tool for each vibration mode based on the maximum equivalent value of the current for that vibration mode indicated by the read data and a coefficient for that vibration mode; 9. An assembly according to claim 7 or 8.

10. a foot switch connected to the processor; The processor: determining the amount of depression of the foot switch; determining the target equivalent value of the current flowing through the mechanical part of the ultrasonic surgical tool for each vibration mode based on the maximum equivalent value of the current of the vibration mode indicated by the read data, a coefficient of the vibration mode, and the depression amount of the foot switch; 10. The assembly of claim 9.

11. 1. A sleeve for an ultrasonic surgical tool having a tip and at least one driver to which said tip is connected and to which an AC drive signal is supplied from a control console to vibrate said tip, comprising: the tip is configured to vibrate in a plurality of vibration modes; a body portion disposed around the tip portion and positioned such that the ultrasonic surgical tool can be actuated to vibrate the tip portion, the body having open proximal and distal ends and a flow path for irrigation fluid to flow along the sleeve and out the open distal end during actuation of the ultrasonic surgical tool to vibrate the tip portion; a tip memory disposed in the body portion and storing data indicating at least one drive signal characteristic for each vibration mode for controlling operation of the tip; A sleeve having:

12. The sleeve of claim 11 , wherein the at least one drive signal characteristic for each vibration mode comprises a voltage characteristic for that vibration mode.

13. 13. The sleeve of claim 11 or 12, wherein the at least one drive signal characteristic for each vibration mode includes a frequency characteristic for that vibration mode.

14. A sleeve as described in any one of claims 11 to 13, wherein the at least one drive signal characteristic for each vibration mode includes a maximum equivalent value of current flowing through a mechanical component of the ultrasonic surgical tool associated with that vibration mode.

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