Patent Publication Number: US-2004054364-A1

Title: Ultrasonic surgical instrument

Description:
[0001] This application claims priority to U.S. Provisional Application Serial No. 60/267,251, filed Feb. 8, 2001, which is incorporated herein by reference in its entirety. 
    
    
     
       BACKGROUND  
       [0002] 1. Technical Field  
       [0003] The present disclosure relates generally to ultrasonic surgical instruments. More specifically, the present disclosure relates to ultrasonic surgical instruments having an end effector configured to effect tissue dissection, cutting, coagulation, ligation and/or hemostatis and having a microelectromechanical system incorporated therein (“MEMS”), which instrument can be used in open as well as laparoscopic or endoscopic surgical procedures.  
       [0004] 2. Background of Related Art  
       [0005] Ultrasonic instruments for surgical use are well known and are used in a variety of surgical procedures for dissecting, cutting, ligating, effecting coagulation in, and/or effecting hemostasis in tissue. Typically, ultrasonic surgical instruments include a handpiece for grasping the instrument, a transducer attached to the proximal end of the handpiece, and a vibration coupler extending from the transducer through a body of the instrument to an end effector of the instrument. The transducer generates vibrations in the ultrasonic frequency range which are transmitted from the handpiece of the instrument to the end effector via the vibration coupler. This configuration, although effective in some applications, has several drawbacks. For example, the power of the instrument is attenuated when ultrasonic energy is transmitted from a proximal end of a device to a distal end of the device. Further, power losses are enhanced at couplings and seals of the instrument. As such, a large, heavy transducer is required to operate known surgical instruments. Moreover, contact between the vibration coupler and stationary components of the instrument result in mechanical faults in the instrument. Finally, the vibration coupler acts as a pump which draws bodily fluids from the distal end of the instrument to the proximal end of the instrument thereby making sterilization of the instrument after use difficult.  
       [0006] The use of an elongated vibration coupler also limits the operational features of the instrument available to a surgeon. More specifically, because the vibration coupler transmits vibrations from the transducer to the end effector, the inclusion of an articulation joint into the vibration coupler is difficult and inefficient. Accordingly, known ultrasonic instruments typically do not include articulating end effectors. Moreover, because the vibrations are transmitted from the transducer at the proximal end of the instrument to the distal end of the instrument, along a stiff vibration coupler, e.g. an elongated titanium rod, vibration energy is transmitted primarily along the rod in longitudinal waves. Any transverse vibrations that do occur as the energy is transmitted along the length of the vibration coupler reduces the overall effeciency of the system.  
       SUMMARY  
       [0007] An ultrasonic surgical system is provided which includes a sugical instrument having an end effector with a transducer, a control module and a conductive cable interconnecting the surgical instrument to the control module. The control module is adapted to be connected to a power source, which may include an electrical outlet, an a/c generator, or a battery pack, etc., and includes control circuitry to drive the transducer positioned on the end effector of the instrument at an ultrasonic frequency or multiple ultrasonic frequencies independently or sinultaneously. Alternately, the control circuitry may be incorporated into the power source. The ultrasonic instrument includes a handle assembly, a body portion and an integral or removable end effector configured to effect cutting, dissection, ligation, hemostasis and/or coagulation of tissue. The end effector includes an ultrasonic member which is preferably formed from a silicon composite, e.g., silicon-titanium composite material. The transducer is supported on, within or adjacent the ultrasonic member of the end effector. The ultrasonic member may have a variety of different configurations including different hook configurations, rectangular, circular, square, etc. The end effector may also include a clamp member or shear probe. In one preferred embodiment, the endoscopic body portion of the instrument is rotatable about its longitudinal axis to effect rotation of the end effector about the longitudinal axis of the endoscopic body portion. Alternately, the end effector or ultrasonic member may be rotatable independently of the endoscopic body portion of the instrument.  
       [0008] In another preferred embodiment, the surgical instrument includes an articulation member which can be pivoted about a pivot member positional transverse to the longitudianl axis of the body portion using an articulation link. An end effector preferably including a transducer is secured to the articulation member and pivotable with the articulation member in response to reciprocation of the articulation link to effect articulation of the end effector, i.e., vary the angle of the end effector in relation to the longitudinal axis of the instrument. 
     
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
     [0009] Various preferred embodiments of the presently disclosed ultrasonic surgical instrument are described herein with reference to the drawings, wherein:  
     [0010]FIG. 1 is a schematic representation of one embodiment of the presently disclosed ultrasonic surgical system including a surgical instrument for cutting, dissecting, ligating, coagulating and/or effecting hemostasis in tissue;  
     [0011]FIG. 1A is a side view of one preferred alternate embodiment of the ultrasonic member of the presently disclosed ultrasonic instrument;  
     [0012]FIG. 1B is a side view of another preferred alternate embodiment of the ultrasonic member of the presently disclosed ultrasonic instrument;  
     [0013]FIG. 1C is a side view of another preferred alternate embodiment of the ultrasonic member of the presentlu disclosed ultrasonic instrument;  
     [0014]FIG. 1D is a cross-sectional view taken along section lines X-X in FIG. 1C;  
     [0015]FIG. 1E is a cross-sectional view of an alternate embodiment of the ultrasonic member shown in FIG. 1D as would be seen along section line X-X of FIG. 1C;  
     [0016]FIG. 1F is a cross-sectional view of another alternate embodiment of the ultrasonic member shown in FIG. 1D as would be seen along section line X-X of FIG. 1C;  
     [0017]FIG. 1G is a cross-sectional view of yet another alternate embodiment of the ultrasonic member shown in FIG. 1D as would be seen along section line X-X of FIG. 1.  
     [0018]FIG. 1H is a top view of another alternate embodiment of the presently disclosed ultrasonic member;  
     [0019]FIG. 1I is a side perspective view of another embodiment of the presently disclosed ultrasonic member;  
     [0020]FIG. 1J is a side perspective view of another embodiment of the presently disclosed ultrasonic member;  
     [0021]FIG. 1K is a side view of another embodiment of the presently disclosed ultrasonic member;  
     [0022]FIG. 2 is a schematic top representation of one preferred embodiment of the ultrasonic member of the presently disclosed ultrasonic instrument;  
     [0023]FIG. 3 is a side view with portions broken away of the distal end of another preferred embodiment of the presently disclosed ultrasonic surgical instrument including an articulating end effector;  
     [0024]FIG. 4 is a top view with portions broken away of the distal end of the presently disclosed ultrasonic sugical instument shown in FIG. 3;  
     [0025]FIG. 4a is a top view with portions broken away of the distal end of the ultrasonic instrument shown in FIG. 4 in an articulated position;  
     [0026]FIG. 5 is a top view of a preferred embodiment of an ultrasonic member of the presently disclosed ultrasonic surgical instrument;  
     [0027]FIG. 6 is a side cross-sectional view with portions broken away of a proximal portion of another preferred embodiment of the presently disclosed ultrasonic instrument; and  
     [0028]FIG. 7 is a side cross-sectional view with portions broken away of the distal end of the ultrasonic instrument shown in FIG. 6. 
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS  
     [0029] Preferred embodiments of the presently disclosed ultrasonic surgical instrument will now be described in detail with reference to the drawings, in which like refence numerals designate identical or corresponding elements in each of the several view.  
     [0030]FIG. 1 illustrates a schematic view of an ultrasonic surgical system shown generally as  10 . System  10  includes an ultrasonic instrument  12 , a control module  14  and conductive cable  16  interconnecting instrument  12  to control module  14 . Ultrasonic instrument  12  may be configured for open, endoscopic or laparoscopic sugical procedures and includes a handle assembly  18 , an elongated body  20  and an end effector  22 . Handle assembly  12  may have a pistol grip configuration, althrough other handle configurations are envisioned, e.g., in-line handle, pencil grips, standard scissor grips, new ergonomically designed grips, etc. Rotation knob  13  may be provided to facilitate rotation of elongated body  20  in known manner. End effector  22  includes a pivotable clamp member  24  and a linear ultrasonic member  26 . Alternatively, the ultrasonic member of the end effectors may assume a variety of other configurations including, inter alia, J-hook (FIG. 1A), L-hook (FIG. 1B), shears (FIG. 1C) having a variety of different cross-sectional shapes (FIGS.  1 D- 1 G), spatula (FIG. 1H), arcuate (FIGS. 1I AND 1J) and rectangular (FIG. 1K). The end effector may also be configured to have a curved blade such as the blade disclosed in U.S. Pat. No. 6,024,750, filed on Aug. 14, 1997 and/or an angled blade, such as disclosed in U.S. Pat. No. 6,036,667, filed on Oct. 4, 1996, both of which are incorporated herein in their entirety by reference.  
     [0031] The ultrasonic member may be formed using an etching process, e.g., isotropic etching, deep reactive ion etching, etc. Suitable etching processes are disclosed in U.S. Pat. No. 5,728,089 filed Oct. 31, 1994, which is also incorporated herein in its entirety by reference. Alternately, other known means may be used to form the ultrasonic member including a variety of different mechanical processes.  
     [0032] As illustrated, control module  14  may include a power cord  15  for engagement with an electrical outlet (not shown). Alternately, module  14  may be adapted to receive power from a battery pack or from an a/c generator. It is also envisioned that a generator or other power source may be incorporated into control module  14 .  
     [0033] Module  14  includes electronic control circuitry to drive a transducer (not shown) positioned on instrument  12  at one or more ultrasonic frequencies. Protective circuitry is provided to prevent injury to a patient, a surgeon or system hardware. Module  14  also includes display circuitry and hardware to provide information to and accept information from a user. This information may be obtained from sensors (not shown) positioned on the instrument end effector. The sensors may be provided to monitor the temperature or, ultrasonic or electric impedence, of the tissue being operated on. Feedback circuitry may be provided to interact with any sensors provided to provide more effective ligation, cutting, dissection, coagulation, etc. For example, the feedback circuitry may terminate operation of the system if a sensor indicates that tissue temperature or ultrasonic or electrical impedence has exceeded a predetermined maximum. The ultrasonic impedence increases as tissue hardens due to rising temperatures. Similarly, electrical impedence is reduced when tissue water level is decreased due to overheating. The feedback circuitry may be selectively activated and deactivated and/or controlled or monitored by a surgeon to provide a surgeon more flexibility in operating the instrument. Further, control module  14  may include diagnostic circuitry to aid in testing and/or debugging instrument  12  or its hardware.  
     [0034] It is contemplated that operation of ultrasonic instrument  12  may be automatically controlled through the use of a computer. In one preferred alternative embodiment of the presently disclosed system, a computer  21  receives data from sensors positioned on the end effector of the ultrasonic instrument. As discussed above, sensors may be provided to monitor different characteristics of the tissue being operated upon including, inter alia, temperature and/or ultrasonic or electrical impedance. Computer  21  preferably includes circuitry to process an analogue signal received from the sensor(s) and to convert the analogue signal to a digital signal. This circuitry may include means to amplify and filter the analogue signal. Thereafter, the digital signal can be evaluated and operation of the ultrasonic instrument can be modified to achieve the desired effect in or on the tissue and prevent damage to surrounding tissue. Computer  21  may be incorporated into control module  14  or linked to control module  14  to effect the desired or appropriate modification of the operation of the instrument  12 .  
     [0035]FIG. 2 illustrates a top or side schematic view of ultrasonic member  26  of an end effector  22 . Ultrasonic member  26  includes a body portion  30  which is preferably formed of components made of silicon material. Alternately, materials such as titanium or other metals may be bonded or joined in some manner to the silicon to improve fracture resistance. It is envisioned that materials other than silicon which are suitable for ultrasonic use may be used to form ultrasonic member  26 . A transducer  32 , preferably a piezoelectric transducer, is supported on, or bonded to or within ultrasonic member  26 . Piezoelectric transducer  32  is connected to the power source and control module  14  by an electrical connector, preferably a cable  34 . Cable  34  may extend proximally from transducer  32  through body  20  of instrument  12  (FIG. 1) and exit instrument  12  through an opening (not shown) in the handle assembly  18  of the instrument.  
     [0036] As discussed above, ultrasonic member  26  may assume a variety of different configurations (FIGS.  1 A- 1 K) and may be attached to a distal portion of instrument  12  in any known manner. For example, ultrasonic member  26  may be secured to a substrate or shaft or a mounting member (not shown) supported within a distal end of body  20  of instrument  12  such as by a snap-fit connection, a set screw or crimping or swaging. A threaded shank  40  or other attachment structure formed on or disposed on or in a proximal end of member  26  may be provided for attachment of ultrasonic member  26  to the distal end of instrument  12 .  
     [0037] Transducer  32  can be positioned on or within or adjacent ultrasonic member  26  to effect vibration along any axis, e.g., the x-axis, the y-axis or any axis in between the x and y axis. Ultrasonic member  26  includes an operating surface generally designated  42  configured to effect dissection, cutting, coagulation, ligation and/or to effect hemostasis of tissue. Alternately, ultrasonic member  26  may include multiple operating surfaces to perform different tasks, e.g., cutting and coagulation. System  10 , including instrument  12 , can be used in a variety of surgical applications including general procedures, gynecologic, urologic, thoracic, cardiac and neurologic surgical procedures. Instrument  12  may be configured to perform both endoscopic and open surgical procedures and may be actuated via a finger switch or a foot pedal in a known manner. The actuation device may include wireless transmission circuitry to effect actuation of instrument  12 .  
     [0038] By providing a transducer on, in or adjacent the distal tip of the instrument, the following benefits can be realize: a) the need for an elongated vibration coupler formed of titanium is obviated substantially reducing the cost of the instrument; b) the length of the body portion of the instrument can be changed, e.g., shortened or lengthened, with virtually no consequential change in instrument performance, e.g., since the instrument vibration coupler has been replaced by an electrical conductor, the instrument need not be retuned, at considerable expense, after changes in body length; c) ultrasonic energy can be transferred to a patient more efficiently, thus lowering energy power requirements; d) the portion of the instrument that is disposable can be easily varied and may comprise only the instrument tip with a limited reuse handle, the entire instrument or any degree of disposability therebetween; e) because the handle assembly does not support the transducer, the handle assembly can be more ergonomically configured; and f) the use of a small transducer on, in or adjacent the distal end of the instrument in place of a large transducer on the proximal end of the instrument substantially reduces the weight of the instrument and makes it easy to manage especially during delicate surgical procedures.  
     [0039]FIGS. 3 and 4 illustrate the distal end of another preferred embodiment of the presently disclosed ultrasonic surgical instrument shown generally as  112 . Instrument  112  includes an end effector  122  having an ultrasonic member  126  and a clamping jaw  124 , a body portion  120  defining a hollow throughbore, an articulation member  150  and an articulation link  152  (FIG. 4). Ultrasonic member  126  includes a transducer  132 . Preferably, the transducer is located as close to the distal end of ultrasonic member  112  as possible. A wire  160  interconnects transducer  132  to a power source (not shown). End effector  122  is supported within articulation member  150  and articulation member  150  is pivotably supported by members  154  about projections  154   a  to body portion  120 . Articulation link  152  has a distal end which is pivotably connected to articulation member  150  at a location offset from pivot members  154 . Articulation link  152  is linearly movable within body  120  to pivot member  150  about projections  154  to effect articulation of end effector  122 . Articulation member  150  may be configured to effect articulation over an angle of between 5° and 175° and preferably between 30° and 120°. Because transducer  132  is supported on ultrasonic member  126  of end effector  122 , end effector  122  of ultrasonic instrument  112  can be articulated without interfering with the vibratory operation of the ultrasonic member (See FIG. 4A.)  
     [0040]FIG. 5 illustrates one preferred embodiment of an ultrasonic member, shown generally as  100 , suitable for use in the presently disclosed ultrasonic surgical instrument of ultrasonic surgical system  10 . Ultrasonic member  100  is preferably a piezoelectric laminate structure which includes a frame  102 , a resonant structure  104 , and a transducer  106 . Alternately, other transduction mechanisms, other than piezoelectric may be used including thermal stress, electrostriction, magnetostriction or optical drive mechanisms. Transducer  106  preferably includes a pair of PZT crystals  108  separated by silicon plate  110 . Alternately, it is envisioned that crystals other than PZT crystals may be used to convert electrical power to effect mechanical vibration. An appropriate bonding agent or process, e.g., solder bonding, diffusion bonding, adhesives, etc., is used to fasten crystals  108  to plate  110 . Resonant structure  104  is preferably formed from a silicon or metal resonant structure or a silicon/metal composite. Structure  104  preferably includes first and second resonant members  104   a  and  104   b.  The proximal end of members  104   a  and  104   b  together define a cavity for receiving transducer  106 . Alternately, resonant structure  104  may be monolithically formed from a single piece of material. The mating surfaces of PZT crystals  108  and resonant members  104   a  and  104   b  are fastened together using an appropriate bonding agent or bonding process, e.g., glass binding, adhesives, etc. Frame  102  includes a body  112  which is preferably formed from a rigid material including metals, ceramics, etc. and includes a cavity  114  dimensioned and configured to receive the resonant structure  104  and transducer  106  assembly. A bonding layer or layers  118 , preferably formed of a conductive material, is positioned between the proximal portion of resonant members  104   a  and  104   b  and frame  102  to bond transducer  106  which is movable to frame  102  which is stationary. The proximal end of frame  102  includes a throughbore  120  which is dimensioned to permit passage of an electrical conductor  122 , e.g., a wire or coaxial cable, to provide power to transducer  106 . The electrical conductor is preferably a high-voltage high-frequency Teflon insulator cable, although the use of other conductors is envisioned. The distal end of conductor  122  is connected to plate  110  by a flexible conductive wire  124  which does not restrict relative movement between frame  102  and transducer  106 .  
     [0041] As discussed above, the shape of resonant structure  104  may be different than that shown in FIG. 5. More specifically, distal operating surface  126  resonant sturcture  104  may assume any of the configurations shown in FIGS.  1 A- 1 K or any other configuration not shown herein which may be advantageous for performing a particular surgical procedure. Moreover, a clamp may be provided to facilitate gripping of tissue.  
     [0042] Ultrasonic member  100  can be actuated in both high and low frequency ranges. In the low frequency range, approximately 20-100 KHz, the instrument will cause cavitation in tissue to effect cutting of the tissue. In the high frequency range, greater than 1 MHz, the instrument may be used for heating and coagulation of tissue. The high and low frequency actuation may occur sinultaneously by an electronic power amplifier, capable of generating both frequencies. Providing multiple frequencies may provide improved cutting in tissue with reduced thermal spread and improved coagulation and hemostasis.  
     [0043] As discussed above, power losses and inefficiencies are substantially reduced as compared to conventional ultrasonic instruments by placing the ultrasonic energy generating PZT element adjacent, on or within the ultrasonic member of the end effector. Whereas conventional instruments may require 40-50 watts of electrical power to effect cutting of tissue, it is envisioned that the presently disclosed ultrasonic instrument will require only 20-30 watts of electrical energy to effect the cutting of tissue. Moreover, it is envisioned that the presently disclosed laminated structure of ultrasonic member  100  is operable at higher frequencies than conventional instruments. Because it is believed the use of higher frequencies may speed the rate of coagulation at a given power setting, the power requirements may be further reduced by operation of the instrument at higher frequencies.  
     [0044]FIGS. 6 and 7 illustrate another preferred embodiment of the presently disclosed ultrasonic instrument shown generally  212 . Ultrasonic instrument  212  includes a handle assembly  218  (FIG. 6), an elongated body  220  and an end effector  222  (FIG. 7). Handle assembly  218  includes a stationary handle portion  260  and a pivotable handle portion  262 . Pivotable handle  262  is pivotably mounted to body portion  264  of handle assembly  218  about a pivot member  266  and is movable from a non-actuated position (FIG. 6) to an actuated position by moving handle  262  towards handle  260  against the bias of biasing member  268  in the direction indicated by arrow “A” in FIG. 6. A link  270  translates the pivotable movement of handle  262  to a linear drive member  272 . Link  270  has a first pivotably secured to pivotable handle  262  by a pin  274  and a second end pivotably secured to drive member  272  by a pin  276 . Upon movement of pivotable handle  262  to the actuated position, linear drive member  272  moves in the direction indicated by arrow “B” in FIG. 6.  
     [0045] A flexible clamping rod or link  252  has a proximal end secured to drive member  272 . Clamping link  252  is preferably formed of a shape memory or resilient material and has a distal end connected to a pivotable clamp member  224  (FIG. 7). Clamp member  224  is pivotably secured within a mounting member  250  by a pivot member  278 . The distal end of clamping link  252  is pivotably connected to pivotable clamp member  224  by a pin  280  at a location offset from pivot member  278 . In use, when handle  262  is moved in the direction indicated by arrow “A” (FIG. 6) to move drive member  272  in the direction indicated by arrow “B”, clamp link  270  is advanced distally in a direction indicated by arrow “C” in FIGS. 6 and 7. Distal movement of clamp link  270  pivots clamp member  224  about pivot member  278  in the direction indicated by arrow “D” in FIG. 7 to a clamped position in juxtaposed alignment with ultrasonic member  226 .  
     [0046] As illustrated in FIG. 6, an articulation link  253  is slidably positioned within body portion  264  of handle assembly  218 . Link  253  includes a proximal end  253   a  which extends through a slot  282  formed in body portion  264 . A slide member  284  is secured to proximal end  253   a  of link  253  and is movable along the outer surface of body portion  264  in the direction indicated by arrow “E” to effect distal movement of articulation link  253 .  
     [0047] Referring to FIG. 7, a mounting member  250  is pivotably secured to the distal end of elongated body  220  by pivot members  284 . Pivot members  284  each include first and second projections  284   a  and  284   b,  respectively. Projections  284   a  are pivotably secured to elongated body  220  and projections  284   b  are pivotably secured to mounting member  250  such that mounting member  250  is pivotable with respect to elongated body  220  about a transverse axis Y. The distal end of articulation link  253  is engaged with a projection (not shown) extending outwardly from an inner surface of mounting member  250 . The projection is laterally offset from pivot axis Y. When link  253  is moved distally or proximally, mounting member  250  is pivoted about pivot axis Y to an articulated position. See FIG. 4A. In a preferred embodiment, mounting member  250 , and thus end effector  222 , can be articulated over an arc of about 150°.  
     [0048] End effector  222  includes clamp member  224  and ultrasonic member  226 . Ultrasonic member  224  is secured within mounting member  250  using any known fastening technique including crimping, swaging, screws, etc. Ultrasonic member  224 , although shown schematically, is substantially the same as ultrasonic member  100 , except operating surface  126  includes a blade configuration. As discussed above, when mounting member  250  is pivoted about axis Y by articulation link  253 , end effector  222  including ultrasonic member  224  are also pivoted, i.e., articulated, about transverse axis Y.  
     [0049] It will be understood that various modifications may be made to the embodiments disclosed herein. For example, the configuration of the ultrasonic member of the end effector need not be as shown herein but rather may be modified to suit a particular surgical application. Further, the transducer may be mounted proximally of the ultrasonic member of the end effector in the distal end of the instrument and need not be mounted directly to the ultrasonic member. Therefore, the above description should not be construed as limiting, but merely as exemplifications of preferred embodiments Those skilled in the art will envision other modifications within the scope and spirit of the claims appended hereto.