Abstract:
An electrosurgical instrument having a movement sensing device for controlling the electrosurgical output thereof, is disclosed. In one aspect of the present disclosure, the electrosurgical instrument includes an elongated housing, an electrically conductive element supported within the housing and extending distally from the housing, the electrically conductive element connectable to a source of electrosurgical energy, and a sensor disposed within the housing and in electrical connection with the electrosurgical generator. The sensor detects movement of the electrically conductive element and communicates a signal to the electrosurgical generator relating to the movement of the electrically conductive element. The source of electrosurgical energy supplies electrosurgical energy in response to the signal from the sensor.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application is a continuation of U.S. application Ser. No. 10/781,084, filed Feb. 17, 2004, now U.S. Pat. No. 7,235,072, which claims the benefit of and priority to U.S. Provisional Patent Application No. 60/448,520, filed on Feb. 20, 2003, and U.S. Provisional Patent Application No. 60/533,695, filed Jan. 1, 2004, the entire contents of which are incorporated herein by reference. 
    
    
     BACKGROUND 
     1. Technical Field 
     The present disclosure relates generally to an electrosurgical instrument and, more particularly, to an electrosurgical pencil having a motion detector for controlling the electrosurgical output thereof. 
     2. Background of Related Art 
     Electrosurgical instruments have become widely used by surgeons in recent years. Accordingly, a need has developed for equipment that is easy to handle, is easy to operate, and is reliable and safe. By and large, most surgical instruments typically include a variety of hand-held pencils, e.g., electrosurgical pencils, forceps, scissors and the like, and electrosurgical pencils, which transfer energy to a tissue site. The electrosurgical energy is initially transmitted from an electrosurgical generator to an active electrode which, in turn, transmits the electrosurgical energy to the tissue. In a monopolar system, a return electrode pad is positioned under the patient to complete the electrical path to the electrosurgical generator. A smaller return electrode is positioned in bodily contact with or immediately adjacent to the surgical site in a bipolar system configuration. 
     For the purposes herein, the term electrosurgical fulguration includes the application of an electric spark to biological tissue, for example, human flesh or the tissue of internal organs, without significant cutting. The spark is produced by bursts of radio-frequency electrical energy generated from an appropriate electrosurgical generator. Generally, electrosurgical fulguration is used to dehydrate, shrink, necrose or char tissue. As a result, electrosurgical fulguration instruments are primarily used to stop bleeding and oozing of various surgical fluids. These operations are generally embraced by the term “coagulation.” Meanwhile, electrosurgical “cufting” includes the use of the applied electric spark to tissue which produces a cutting effect. By contrast, electrosurgical “sealing” includes utilizing a unique combination of electrosurgical energy, pressure and gap distance between electrodes to melt the tissue collagen into a fused mass. 
     It is known that certain electrosurgical waveforms are preferred for different surgical effects. For example, a continuous (i.e., steady) sinusoidal waveform is preferred to enhance the cutting effect of the electrosurgical blade in an electrosurgical pencil or enhance the cooperative effect of the two opposing jaw members. A series of discontinuous, high energy electrosurgical pulses are preferred to enhance the coagulation of biological tissue. Other types of electrosurgical waveforms are preferred for electrosurgical “blending”, “shorting” or fusing tissue. As can be appreciated, these waveforms are typically regulated by the generator and are generally dependent upon the desired mode of operation manually selected by the surgeon at the onset (or during) the operation. 
     As used herein, the term “electrosurgical pencil” is intended to include instruments which have a handpiece which is attached to an active electrode and are used to coagulate, cut, and seal tissue. The pencil may be operated by a hand-switch (in the form of a depressible button provided on the handpiece itself) or a foot-switch (in the form of a depressible pedal operatively connected to the handpiece). The active electrode is an electrically conducting element which is usually elongated and may be in the form of a thin flat blade with a pointed or rounded distal end. Typically, electrodes of this sort are known in the art as “blade” type. Alternatively, the active electrode may include an elongated narrow cylindrical needle which is solid or hollow with a flat, rounded, pointed or slanted distal end. Typically, electrodes of this sort are known in the art as “loop” or “snare”, “needle” or “ball” type. 
     As mentioned above, the handpiece of the pencil is connected to a suitable electrosurgical source (e.g., generator) which supplies the electrosurgical energy necessary to the conductive element of the electrosurgical pencil. In general, when an operation is performed on a patient with an electrosurgical pencil, energy from the electrosurgical generator is conducted through the active electrode to the tissue at the site of the operation and then through the patient to a return electrode. The return electrode is typically placed at a convenient place on the patient&#39;s body and is attached to the generator by a return cable. 
     During the operation, the surgeon depresses the hand-switch or foot-switch to activate the electrosurgical pencil. Then, depending on the level of radio-frequency electrosurgical energy desired for the particular surgical effect, the surgeon manually adjusts the power level on the electrosurgical generator by, for example, rotating a dial on the electrosurgical instrument. Recently, electrosurgical pencils have been developed which vary the level of electrosurgical energy delivered depending on the amount of drag sensed by the active electrode or by the degree the hand-switch has been depressed by the surgeon. Examples of some of these instruments are described in commonly assigned U.S. Provisional Application Nos. 60/398,620 filed Jul. 25, 2002 and 60/424,352 filed Nov. 5, 2002, the entire contents of which are hereby incorporated by reference. 
     Accordingly, a need exists for an electrosurgical pencil which is activated without the use of hand-switches or foot-switches and which can automatically control the electrosurgical output from the electrosurgical generator without manual intervention by the surgeon. 
     SUMMARY 
     An electrosurgical instrument having a movement sensing device for controlling the electrosurgical output thereof, is disclosed. In one aspect of the present disclosure, the electrosurgical instrument includes an elongated housing, an electrically conductive element supported within the housing and extending distally from the housing, the electrically conductive element being connectable to a source of electrosurgical energy, and a sensor disposed within the housing and in electrical connection with the electrosurgical generator. The sensor detects movement of the electrically conductive element and communicates a signal to the electrosurgical generator relating to the movement of the electrically conductive element. The source of electrosurgical energy supplies electrosurgical energy in response to the signal communicated from the sensor. 
     It is envisioned that the sensor for detecting movement of the electrically conductive element is at least one of force-sensing transducers, accelerometers, optical positioning systems, radiofrequency positioning systems, ultrasonic positioning systems and magnetic field positioning systems. 
     Preferably, the electrically conductive element includes a longitudinal axis defined therethrough and the sensor detects at least one of a axial movement of the electrically conductive element along the longitudinal axis, a transverse movement across the longitudinal axis of the electrically conductive element, and a rotational movement about the longitudinal axis of the electrically conductive element. In one embodiment it is envisioned that the source of electrosurgical energy transmits a dissecting RF energy output in response to the detection of axial movement of the electrically conductive element along the longitudinal axis. In another embodiment it is envisioned that the source of electrosurgical energy transmits a hemostatic RF energy output in response to the detection of transverse movement of the electrically conductive element across the longitudinal axis. 
     It is envisioned that the sensor is at least one of a differential parallel plate accelerometer, a balanced interdigitated comb-finger accelerometer, an offset interdigitated comb-finger accelerometer and a film-type accelerometer. Preferably, the sensor includes a first accelerometer for detecting a movement of the electrically conductive element in an axial direction along the longitudinal axis and a second accelerometer for detecting movement of the electrically conductive element in a transverse direction across the longitudinal axis. It is also envisioned that the sensor may include at least one piezoelectric film. 
     In one embodiment it is contemplated that the first accelerometer is configured and adapted to transmit an output signal to the electrosurgical energy source corresponding to the axial movement of the electrically conductive element, and the second accelerometer is configured and adapted to transmit an output signal to the electrosurgical energy source corresponding to the transverse movement of the electrically conductive element. Preferably, each of the first and second accelerometers is at least one of a differential parallel plate accelerometer, a balanced interdigitated comb-finger accelerometer, an offset interdigitated comb-finger accelerometer and a film-type accelerometer. 
     In certain embodiments it is envisioned that the source of electrosurgical energy ceases supplying electrosurgical energy when the sensor does not detect a movement of the electrosurgical pencil for a predetermined period of time and/or does not detect a movement of the electrosurgical pencil above a predetermined threshold level of movement. 
     It is further envisioned that in certain embodiments the source of electrosurgical energy resumes supplying electrosurgical energy when the sensor detects a movement of the electrosurgical pencil following the predetermined period of time and/or detects a movement of the electrosurgical pencil above the predetermined threshold level of movement. 
     These and other objects will be more clearly illustrated below by the description of the drawings and the detailed description of the preferred embodiments. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings, which are incorporated and constitute a part of this specification, illustrate embodiments of the disclosure and, together with a general description of the disclosure given above, and the detailed description of the embodiments given below, serve to explain the principles of the disclosure. 
         FIG. 1  is a partially broken away side, elevational view of an embodiment of the electrosurgical pencil in accordance with the present disclosure; 
         FIGS. 2A-2C  illustrate three embodiments of accelerometers suitable for in-plane sensing or forcing; 
         FIG. 3  is a partially broken away perspective view of an electrosurgical pencil in accordance with another embodiment of the present disclosure; and 
         FIG. 4  is an enlarged perspective view of the indicated area of  FIG. 3 . 
     
    
    
     DETAILED DESCRIPTION 
     Embodiments of the presently disclosed electrosurgical pencil will now be described in detail with reference to the drawing figures wherein like reference numerals identify similar or identical elements. In the drawings, and in the description which follows, as is traditional, the term “proximal” will refer to the end of the electrosurgical pencil which is closest to the operator, while the term “distal” will refer to the end of the electrosurgical pencil which is furthest from the operator. 
     Acceleration is a physical quality which often must be sensed or measured. Acceleration is defined as the rate of change of velocity with respect to time. For example, acceleration is often sensed to measure force or mass, or to operate some kind of control system. At the center of any acceleration measurement is an acceleration-sensing element, or force-sensing transducer. The transducer is often mechanical or electromechanical element (e.g., a piezo-electric transducer, a piezo-resistive transducer or a strain gauge) which is typically interfaced with an electrical signal or electrical circuits for providing a useful output signal to a generator, computer or other surgical console. Exemplary transducers are described in U.S. Pat. Nos. 5,367,217, 5,339,698, and 5,331,242, the entire contents of which are incorporated herein by reference. An accelerometer is defined as an instrument which measures acceleration or gravitational force capable of imparting acceleration. Another type of force-sensing transducer is an accelerometer. Exemplary accelerometers are described in U.S. Pat. Nos. 5,594,170, 5,501,103, 5,379,639, 5,377,545, 5,456,111, 5,456,110, and 5,005,413, the entire contents of which are incorporated herein by reference. 
     Several types of accelerometers are known. A first type of accelerometer incorporates a bulk-micromachined silicon mass suspended by silicon beams, wherein ion-implanted piezo-resistors on the suspension beams sense the motion of the mass. A second type of accelerometer utilizes a change in capacitance to detect movement of the mass. A third type of accelerometer detects acceleration by measuring a change in a structure&#39;s resonant frequency as a result of a shift in the physical load of the structure. It is envisioned that the accelerometers can include a piezoelectric film sandwiched into a weighted printed flex circuit. It is also envisioned that at least one resistive flex circuit could be used to detect the position and/or orientation of the surgical instrument rather than acceleration. 
     Turning now to  FIG. 1 , there is set forth a partially broken away side, elevational view of an electrosurgical pencil constructed in accordance with an embodiment of the present disclosure and generally referenced by numeral  100 . While the following description will be directed towards electrosurgical pencils, it is envisioned that the features and concepts of the present disclosure can be applied to other electrosurgical instruments, e.g., dissectors, ablation instruments, probes, etc. Electrosurgical pencil  100  includes an elongated housing  102  configured and adapted to support a blade receptacle  104  at a distal end  103  thereof which, in turn, receives an electrocautery blade  106  therein. A distal end  108  of blade  106  extends distally from receptacle  104  while a proximal end  110  of blade  106  is retained within the distal end  103  of housing  102 . Preferably, electrocautery blade  106  is fabricated from a conductive material, e.g., stainless steel or aluminum or is coated with an electrically conductive material. 
     As shown, electrosurgical pencil  100  is coupled to a conventional electrosurgical generator “G” via a cable  112 . Cable  112  includes a transmission wire  114  which electrically interconnects electrosurgical generator “G” with proximal end  110  of electrocautery blade  106 . Cable  112  further includes a control loop  116  which electrically interconnects a movement sensing device  124  (e.g., an accelerometer), supported within housing  102 , with electrosurgical generator “G”. 
     By way of example only, electrosurgical generator “G” may be any one of the following, or equivalents thereof: the “FORCE FX”, “FORCE 2” or “FORCE 4” generators manufactured by Valleylab, Inc., a division of Tyco Healthcare, LP, Boulder, Colo. Preferably, the energy output of electrosurgical generator “G” can be variable in order to provide appropriate electrosurgical signals for tissue cutting (e.g., 1 to 300 watts) and appropriate electrosurgical signals for tissue coagulation (e.g., 1 to 120 watts). One example of a suitable electrosurgical generator “G” is disclosed in commonly-assigned U.S. Pat. No. 6,068,627 to Orszulak, et al., the entire contents of which are incorporated herein by reference. The electrosurgical generator disclosed in the &#39;627 patent includes, inter alia, an identifying circuit and a switch therein. In general, the identification circuit is responsive to the information received from a generator and transmits a verification signal back to the generator. Meanwhile, the switch is connected to the identifying circuit and is responsive to signaling received from the identifying circuit. 
     Electrosurgical pencil  100  further includes an activation button  126  supported on an outer surface of housing  102 . Activation button  126  is operable to control a depressible switch  128  which is used to control the delivery of electrical energy transmitted to electrocautery blade  106 . 
     Turning back to  FIG. 1 , as mentioned above, electrosurgical pencil  100  includes an accelerometer  124  which is supported within housing  102 . Accelerometer  124  is operatively connected to generator “G” which, in turn, controls and transmits an appropriate amount of electrosurgical energy to electrocautery blade  106  and/or controls the waveform output from electrosurgical generator “G”. 
     In use, the surgeon activates electrosurgical pencil  100  by depressing activation button  126  thereby allowing electrical energy to be transmitted to electrocautery blade  106 . With activation button  126  depressed, as the surgeon moves electrosurgical pencil  100  repeatedly along the X axis (i.e., in a stab-like motion), as indicated by double-headed arrow “X” in  FIG. 1 , accelerometer  124  transmits a corresponding signal, through control loop  116 , to generator “G”. Generator “G” then interprets the signal received from accelerometer  124  and, in turn, transmits a corresponding dissecting electrosurgical energy output (i.e., specific power and waveform associated with dissecting), via transmission wire  114 , to electrocautery blade  106 . 
     On the other hand, if the surgeon moves electrosurgical pencil  100  in a direction orthogonal to the X axis, for example, as indicated by double-headed arrow “Z” in  FIG. 1 , accelerator  124  transmits a corresponding signal, through control loop  116 , to generator “G”. Generator “G” then interprets the orthogonal signal received from accelerometer  124  and, in turn, transmits a hemostatic electrosurgical energy output (i.e., specific power and waveform associated with hemostasis), via transmission wire  114 , to electrocautery blade  106 . 
     Accordingly, the electrosurgical pencil of the present disclosure will enable a surgeon to control the type of output and/or the amount of energy delivered to electrocautery blade  106  by simply moving electrosurgical pencil in a particular pattern or direction. In this manner, the surgeon does not have to depress any buttons or switches which are disposed on the electrosurgical pencil  100  in order to produce either a dissecting or hemostasis energy output in electrocautery blade  106 . As can be appreciated, the surgeon does not have to adjust dials or switches on generator “G” in order to produce either the dissecting or hemostasis energy output in electrocautery blade  106 . 
     Accelerometers suitable for position sensing or electrostatic forcing may be formed with fixed and movable electrodes in many configurations. Several embodiments of accelerometers having in-plane motion sensitivity are shown in  FIG. 2 , along with an orthogonal coordinate system. In particular, as seen in  FIGS. 2A-2C , a differential parallel plate accelerometer is shown generally as  150 . Differential parallel plate accelerometer  150  includes an electrode  152 , attached to a proof mass  154 , which is movable along the Y-axis thereby changing the gap between movable electrode  152  and fixed electrodes  156  and  158 . Motion of movable electrode  152 , along the Y-axis, causes opposite changes in capacitance formed by electrode pair  152 ,  156  and  152 ,  158 . In  FIG. 2B , a balanced, interdigitated comb-finger accelerometer is shown generally as  160 . 
     Balanced, interdigitated comb-finger accelerometer  160  includes an electrode  162 , attached to a proof mass  164 , which is movable along the Y-axis thereby changing the overlap area between movable electrode  162  and a fixed wrap-around electrode  166 . In  FIG. 2C , an offset, interdigitated comb-finger accelerometer is shown generally as  170 . Offset, interdigitated comb-finger accelerometer  170  includes an electrode  172 , attached to a proof mass  174 , which is movable along the Y-axis thereby changing gaps between movable electrode  172  and a fixed wrap-around electrode  176 . 
     While a single accelerometer  124  which can measure changes in the acceleration of electrosurgical pencil  100  in the axial (i.e., X-direction), lateral (i.e., Y-direction) and vertical (i.e., Z-direction) directions is preferred, it is envisioned that a pair of identical accelerometers or different accelerometers (i.e., accelerometers  150 ,  160  and  170 ), as shown in  FIGS. 2A-2C , can be used. For example, a first accelerometer, such as, offset interdigitated comb-finger accelerometer  170 , can be mounted within electrosurgical pencil  100  such that a displacement of movable electrode  172  in the Y-direction results in the transmission of dissecting electrosurgical energy by generator “G” to electrocautery blade  106  while a second accelerator, such as, another offset interdigitated comb-finger accelerometer  170 , can be mounted within electrosurgical pencil  100 , orthogonal to the first accelerometer, such that a displacement of movable electrode  172  in the X-direction results in transmission of hemostatic electrosurgical energy by generator “G” to electrocautery blade  106 . 
     It is envisioned that any combination of accelerometers can be provided in electrosurgical pencil  100  in any number of orientations to measure changes in acceleration in any number of directions including rotational acceleration (Y-direction and Z-direction). It is also envisioned that any combination of accelerations in the X-direction, Y-direction and Z-direction can also be detected, measured and calculated to effect the electrosurgical output from Generator “G”. 
     In addition to accelerometers, it is envisioned that many other types of sensors for detecting movement of electrocautery blade  106  can be provided. Other types of force-sensing transducers may be used. Other types, including and not limited to, optical positioning systems, radiofrequency positioning systems, ultrasonic positioning systems and magnetic field positioning systems may be used. 
     While an active electrode in the form of a blade has been shown and described, it is envisioned that any type of tip can be used as the active electrode of electrosurgical pencil  100 . For example, the active electrode can be an elongated narrow cylindrical needle which is solid or hollow with a flat, rounded, pointed or slanted distal end. 
     It is further envisioned that the amount of time required for the transmission of electrosurgical energy from the generator “G” to the electrocautery blade  106 , in response to an output signal received from the accelerometer  124  can be adjusted based on the degree of responsiveness desired by the surgeon. For example, a relatively shorter response time would be considered more responsive than a relatively longer response time. 
     In addition, it is envisioned that the accelerometer  124  be provided with motion detection algorithms which transmit energy cut-off signals to generator “G” if electrosurgical pencil  100  is held motionless or laid down for an extended period of time. It is contemplated that the sensitivity to activation of electrosurgical pencil  100 , in response to an axial, vertical or transverse movement, may be decreased as time lapses from the last time that electrosurgical pencil  100  was used. As such, electrosurgical pencil  100  would be less likely to be inadvertently activated as more time elapses. In addition, the ability to disable the electrosurgical pencil  100  when not in use improves the clinical safety of the device. The motion detection algorithm effectively creates a “virtual holster” which keeps electrosurgical pencil  100  from being inadvertently activated. 
     Turning now to  FIGS. 3 and 4 , there is set forth a partially broken away perspective view of an electrosurgical pencil constructed in accordance with another embodiment of the present disclosure and generally referenced by numeral  200 . Electrosurgical pencil  200  is similar to electrosurgical pencil  100  and will only be discussed in detail to the extent necessary to identify differences in construction and operation. 
     As seen in  FIGS. 3 and 4 , electrosurgical pencil  200  includes a film-type accelerometer or sensor  224  supported in housing  102 . Sensor  224  is preferably includes substrate  226  fabricated from an elastomeric material. Sensor  224  further includes an array of electrodes  228  (in the interest of clarity only four electrodes  228   a - 228   d  have been shown) positioned around the periphery of substrate  226 . Sensor  224  further includes a proof mass  230  electrically connected to each electrode  228  via electrical leads  232 . Proof mass  230  is movable in any direction along axes X, Y and Z thereby changing the gap distance between itself and electrodes  228  and the resistance through leads  232 . 
     Accordingly, motion of proof mass  230 , along the X, Y and/or Z axis results in transmission of a particular signal, through control loop  116 , to generator “G” (see  FIG. 1 ). Generator “G” then interprets the particular signal received from sensor  224  and, in turn, transmits a corresponding distinct electrosurgical energy output (i.e., specific power and/or waveform), via transmission wire  114 , to electrocautery blade  106 . 
     For example, with activation button  126  depressed, movement by the surgeon of electrosurgical pencil  200  is directions along the X axis (i.e., in a stab-like motion), causes sensor  224  to transmit a first characteristic signal to generator “G”. Generator “G” interprets the first characteristic signal and, in turn, transmits a corresponding dissecting electrosurgical energy output (i.e., a specific power and a specific waveform associated with dissecting), to electrocautery blade  106 . 
     In a further example, with activation button  126  depressed, movement by the surgeon of electrosurgical pencil  200  in directions transverse to the X axis, such as, for example, along the Y and/or Z axes, causes sensor  224  to transmit a second characteristic signal to generator “G”. Generator “G” interprets the second characteristic signal and, in turn, transmits a corresponding hemostatic electrosurgical energy output (i.e., a specific power and a specific waveform associated with hemostasis), to electrocautery blade  106 . 
     It is envisioned that substrate  226  has a concave-like configuration. In this manner, when the surgeon holds electrosurgical pencil  200  still, proof mass  230  will have a tendency to return to the bottom of substrate  226  and effectively reset itself automatically. In other words, a concave-like substrate  226  can be self-centering and thus provide electrosurgical pencil  200  with a self-resetting capability. It is also envisioned that other shapes may be used. 
     Accordingly, the electrosurgical energy output of electrosurgical pencils  100 ,  200  will be controlled by the natural movements of the surgeon&#39;s hand and no specific thought is required to change the corresponding energy output from a “dissecting” setting to a “hemostatic” setting and vice-a-versa. 
     It is envisioned that when electrosurgical pencil  100 ,  200  is held motionless for a predetermined amount of time and/or below a predetermined threshold level of movement (i.e., accelerometer  124  and/or sensor  224  do not sense movement of electrosurgical pencil  100  or  200  for a predetermined period of time and/or sense movement which is below a predetermined threshold level), electrosurgical generator “G” does not transmit electrosurgical energy to the electrocautery blade. It is further envisioned that the sensitivity of electrosurgical pencil  100  or  200  can be increased and/or decreased by adjusting the threshold levels of time and movement accordingly. 
     It is further envisioned that electrosurgical generator “G” begins and/or resumes supplying electrosurgical energy to the electrocautery blade when accelerometer  124  and/or sensor  224  detects a movement of electrosurgical pencil  100  or  200  after the predetermined period of time has elapsed and/or after the predetermined threshold level has been surpassed. 
     From the foregoing and with reference to the various figure drawings, those skilled in the art will appreciate that certain modifications can also be made to the present disclosure without departing from the scope of the present disclosure. For example, embodiments of the present disclosure include an electrosurgical pencil having a button for controlling the electrosurgical energy output, in addition to the sensor or sensors discussed above. While embodiments of electrosurgical instruments according to the present disclosure have been described herein, it is not intended that the disclosure be limited there and that the above description should be construed as merely exemplifications of preferred embodiments.