EP1511536A1

EP1511536A1 - Ultrasonic soft tissue cutting and coagulation systems

Info

Publication number: EP1511536A1
Application number: EP03750129A
Authority: EP
Inventors: Paul Fenton; Francis Harrington; Paul Westhaver
Original assignee: Axya Medical Inc
Current assignee: Axya Medical Inc
Priority date: 2002-05-13
Filing date: 2003-05-13
Publication date: 2005-03-09
Also published as: JP4425782B2; AU2003247365A1; EP1511536A4; JP2005525180A; WO2003095028A1; JP2010005460A

Abstract

The present invention relates to ultrasonic soft tissue cutting or coagulating systems that include an ultrasonic blade member (112) for cutting and/or coagulating tissue, and an opposed clamp member which can be used together with the blade member to compress/clamp the tissue being treated. At least one of the blade member and the clamp member (114) has a substantially curvilinear configuration. This curvilinear configuration can be optimized to improve the coupling of ultrasonic power to the tissue being treated.

Description

ULTRASONIC SOFT TISSUE CUTTING AND COAGULATION SYSTEMS

BACKGROUND OF THE INVENTION

(01) For many years, ultrasonic surgical instruments have been used for soft tissue cutting and coagulation. These ultrasonic instruments include ultrasonic transducers which convert the electric energy supplied by a generator into ultrasonic frequency vibratory energy, which can then be applied to the tissue of a patient. The transducers are typically enclosed within a handpiece or a transducer sheath. Ultrasonic surgical instruments use relatively high-power, low-frequency vibratory energy, typically at a frequency range of about 20 kHz to about 100 kHz.

(02) In general, ultrasonic tissue cutting and coagulation systems include a ultrasonic vibrating member that is coupled to the ultrasonic transducers, and that can be made to vibrate at ultrasonic frequencies. The ultrasonically vibrating member, for example a blade, a probe or a horn, is then applied to the tissue, in order to transmit ultrasonic power to the tissue. In this way, the contacted tissue can be cut or coagulated. Ultrasonic surgical systems offer a number of advantages over conventional surgical systems, for example reduction of bleeding and trauma.

(03) The mechanism through which an ultrasonically vibrating member and the tissue interact, i.e. the physics of ultrasonic soft tissue cutting and coagulation, is not completely understood, however various explanations have been provided by researchers over the years. These explanations include descriptions of mechanical effects and thermal effects. The mechanical viewpoint states that the tip of the ultrasonically vibrating member generates short-range forces and pressures, which are sufficient to dislodge cells in the tissue, and break up the tissue structures. Various types of ferees are postulated as contributing to the rupture of the tissue layer, for example the impact forces resulting from the direct contact of the vibrating tip with tissue, and the shear forces that are the result of the differences in force levels across tissue boundaries. Some energy may be lost due to frictional heating, and due to the heating caused by the absorption of acoustic energy by tissue.

(04) Thermal effects may include frictional heat, generated by the ultrasonically vibrating tip, in an amount sufficient to melt a portion of the contacted tissue. Alternatively, the tissue may absorb the vibratory energy, which it then converts into heat. The generated heat may be used to coagulate a blood vessel, by way of example. Other effects that have been postulated in order to explain the probe-tissue interaction include cavitational effects. The cavitation viewpoint postulates that the coupling of ultrasonic power onto tissue results in the occurrence of cavitation in tissue, namely the formation of gas or vapor-filled cavities or bubbles within the tissue, which may oscillate and propagate. A combination of mechanical, thermal, and cavitational effects may result in the desired surgical outcomes, such as cutting and coagulation.

(05) A number of ultrasonic soft tissue cutting and coagulating systems have been disclosed in the prior art. For example, U.S. Pat. No. 5,322,055 (the '"055 patent"), entitled "Clamp Coagulator / Cutting System For Ultrasonic Surgical Instruments." The '055 patent issued to T.W. Davison et al. on June 21, 1994, and is assigned on its face to Ultracision, Inc.

(06) The '055 patent relates to ultrasonic surgical instruments having a non- vibrating clamp for pressing tissue against an ultrasonically vibrating blade, for cutting, coagulating, and blunt-dissecting of tissue. A handpiece enclosing an ultrasonic transducer is connected to the blade. When ultrasonically activated, the blade undergoes longitudinal mode vibrations, parallel to the blade edge. A clamp accessory, including a clamp member, is releasably connected to the handpiece. The blade is used in conjunction with the clamp member, to apply a compressive force to the tissue in a direction normal to the direction of vibration. In a preferred embodiment of the invention, a clamp member actuation mechanism, for example a scissors-like grip, actuates a pivoted clamp member to compress and bias tissue against the ultrasonic power-carrying blade, in a direction normal to the longitudinal vibratory movement of the blade.

(07) U.S. Pat. No. 6,036,667 (the '"667 patent"), entitled "Ultrasonic Dissection and Coagulation System," issued to R. Manna et al. on March 14, 2000, and is assigned on its face to United States Surgical Corporation and to Misonix Incorporated.

(08) The '667 patent discloses an ultrasonic dissection and coagulation system for surgical use. The ultrasonic system includes a housing, and an elongated body portion extending from the housing. The housing encloses an ultrasonic transducer, which is operatively connected to a cutting blade by a vibration coupler. The cutting blade has a cutting surface which is angled with respect to the longitudinal axis of the elongated body portion, i.e. with respect to the axis of ultrasonic vibration. A clamp member for clamping tissue in conjunction with the blade is movable from an open position in which the operative surface of the clamp is spaced from the cutting surface of the blade, to a clamped position in which the operative surface of the clamp is in close juxtaposed alignment with the cutting surface to clamp tissue therebetween. (09) U.S. Pat. No. 6,056,735 (the "735 patent"), entitled "Ultrasound Treatment System." The '735 patent issued to M. Okada et al. on May 2, 2000, and is assigned on its face to Olympus Optical Co., Ltd.

(10) The '735 patent relates to ultrasonic treatment systems, including endoscopic systems and aspiration systems, for treating living tissue. The '735 patent features an ultrasonic treatment system having a handpiece that encloses ultrasonic transducers, and a probe connected to the transducers and serves as an ultrasonic power conveying member. A treatment unit of the ultrasonic treatment system includes a stationary distal member, to which ultrasonic vibrations are conveyed by the probe, and a movable, holding member. The holding member clamps living tissue, in cooperation with the stationary distal member. A scissors-like manipulating means manipulates the treatment unit to clamp or free living tissue. In a preferred embodiment, a turning mechanism is provided for turning the treatment unit relative to the manipulating means, with the axial direction of the transducers as a center.

(11) The shape and design of the ultrasonically vibrating member, and in pertinent cases the shape and design of the clamp member used to grasp tissue in cooperation with the vibrating member, significantly affect the interaction of an ultrasonic surgical system with tissue.

(12) The prior art ultrasonic systems described above do not disclose ultrasonically vibrating members and/or clamp members which have curvilinear configurations that ensure a substantially uniform delivery of ultrasonic power to the tissue that is in contact with the operative surface of the vibrating member. The prior art ultrasonic systems described above require that the ultrasonically vibrating member be stationary with respect to the clamp or other holding member. Also in the prior art patents discussed above, the ultrasonically vibrating member must cooperate with a clamp or jaw, in order to grasp the tissue that is being treated. In the prior art ultrasonic systems described above, the vibrations of the ultrasonically vibrating element (the component which receives ulfrasonic energy and transmits the ultrasonic energy to the tissue) are limited to longitudinal mode vibrations, i.e. vibrations that are parallel to a longitudinal axis of the vibrating member. In fact, some prior art patents seek to intentionally suppress transverse modes of vibration.

(13) In prior art ultrasonic surgical systems, the constituent parts, such as the ultrasonic transducer, the transducer sheath, the ultrasound transmission coupler, and the ultrasonic surgical blade, are generally precision-cut, and therefore not disposable or replaceable. By way of example, these constituent parts may be precision-cut in order to place a vibratory node (or antinode) of the instrument at the desired or necessary location along the instrument, i.e. in order to tune the vibrations of the ultrasonic instrument at desired frequencies. Using precision-cut component parts allows desired features (for example, the desired frequencies of the ultrasonic vibrations), which are specific to the particular surgical procedure being use or the particular tissue being treated, to be incorporated into the surgical system. However, using precision-cut component parts increases the cost of manufacturing and assembling the ultrasonic surgical instruments.

(14) It is desirable to provide an ultrasonic surgical system which enables soft tissue to be treated evenly across the contact surface, thereby improving the coupling of ultrasonic power to the tissue. It is also desirable to provide an ultrasonic surgical system which enables tissue to be treated according to a desired spatial distribution of ultrasonic power across the contact surface. A moveable ultrasonic vibrating member would also be able to achieve a greater variety of surgical effects. It is also desirable to provide systems having a blade/jaw assembly, in which the ulfrasonically vibrating member can operate (in conjunction with the jaw) without having to perform, by itself, a grasping function. It is desirable to provide a multiple wavelength probe, which enables the simultaneous use of multiple modes of vibration to vibrate a distal probe.

(15) It is also desirable to provide an ultrasonic surgical system having a vibrating element which undergoes vibrational modes that include non-longitudinal modes of vibration, for example transverse, rotational, or flexural modes of vibration, so that a wider variety of surgical effects may be achieved.

(16) In particular, it is desirable to stimulate transverse and rotational modes of vibration, so that the vibrating element can undergo motion perpendicular to the longitudinal axis of the probe.

(17) There is also a need for low cost devices that can be used for ultrasound surgery, and that are formed of inexpensive, disposable, and replaceable component parts, and desirable to provide an improved ultrasonic surgical system that is economical to produce and utilize, and that contains one or more components that is disposable after use.

SUMMARY OF THE INVENTION

(18) The present invention relates to ulfrasonic soft tissue cutting or coagulating systems that include an ulfrasomc blade member for cutting and/or coagulating tissue, and an opposed clamp member which can be used together with the blade member to compress/clamp the tissue being treated. At least one of the blade member and the clamp member has a substantially curvilinear configuration. This curvilinear configuration can be optimized to improve the coupling of ultrasonic power to the tissue being treated.

(19) An ulfrasonic surgical instrument constructed in accordance with one embodiment of the present invention includes one or more ulfrasonic transducers for generating ulfrasonic vibrations. An elongated ultrasonic transmission coupler includes a proximal end and a distal end, and is connected to the ulfrasonic transducer at the proximal end. The transmission coupler receives ulfrasonic vibrations from the transducer, and transmits these ulfrasonic vibrations from its proximal end to its distal end.

(20) An ultrasonic surgical assembly is connected to the distal end of the elongated transmission coupler. In one embodiment, the assembly includes a blade member, and a clamp member. The blade member and the clamp member are movably connected, and cooperate to engage tissue between their respective operative surfaces, hi one embodiment, the blade member is acoustically coupled to the transmission coupler so as to receive ultrasonic power from the coupler. Upon receipt of ultrasonic power, the blade member undergoes vibratory motion. The blade member of the ultrasonic surgical assembly thereby delivers ultrasonic power to contacting tissue, so that desired surgical effects, such as cutting and/or coagulation, can be achieved.

(21) hi another embodiment of the invention, the clamp member may also be acoustically coupled to the fransmission coupler, and undergo vibratory motion upon receipt of ulfrasonic power. In this embodiment, either the blade member or the clamp member, or both, may vibrate ultrasonically. (22) hi the present invention, at least one of the blade member and the clamp member are characterized by a substantially curvilinear configuration. In one embodiment of the invention, the curvilinear configuration of the blade member and/or the clamp member enables ulfrasonic power to be substantially uniformly delivered to the tissue, across the length of the contact surface. In another embodiment of the invention, the curvilinear configuration of the blade member and/or the clamp member permits the delivery of ultrasonic power according to a desired spatial distribution.

(23) In one form of the invention, the blade member is rigidly attached to the fransmission coupler, and the clamp member is movably attached to the coupler, fri this embodiment, the clamp member is movable from an open position in which the blade member and the clamp member are spaced apart, to a closed position in which the blade member and the clamp member are in engagement so as to grasp tissue therebetween, hi an alternative form of the invention, the clamp member is rigidly attached to the transmission coupler, and the blade member is movably attached to the coupler, and is movable from the open position to the closed position, h yet another alternative form of the invention, a scissors-like blade-clamp assembly for an ulfrasonic surgical system has a moveable blade member and a moveable clamp member, in which opposing lateral surfaces of the moveable blade member and the moveable clamp member are adapted for angled interference in response to relative motion therebetween.

(24) h another form of the invention, an ultrasonic soft tissue cutting and coagulation system has a movable ulfrasonic probe member connected to a stationary clamp jaw, an ultrasonic surgical instrument having an ultrasonic transducer for generating ultrasonic vibrations. The probe member is connected to said ultrasonic transducer for receiving ultrasonic vibrations therefrom. The clamp jaw includes a tissue engaging surface. The probe member is movably connected to the clamp jaw. The probe member is movable between an open position spaced from the tissue engaging surface of the clamp jaw, to a clamped position in which the probe member is moved toward the tissue engaging surface so as to capture tissue therebetween. When the surgical instrument is used for cutting tissue, the probe member may include a cutting surface.

(25) In yet another form of the present invention, an ulfrasonic surgical system includes a retractable grasper. The grasper includes a grasping jaw or clamp that is movable in a direction perpendicular to the primary vibratory mode of the ultrasonic blade element. The jaw is preferably hinge-actuated, and is operable to grasp tissue. The jaw is movable between an open, extended position, to a closed position in which the jaw presses against the blade element, in a direction substantially parallel to the direction of vibration of the blade. In this way, tissue is grasped between the jaw and the blade. The grasper allows the ultrasonic blade to be used without need for the blade itself to perform a grasping function.

(26) In yet another form, the invention is directed to ultrasonic soft tissue cutting or coagulating systems in which multiple modes of vibration can be used simultaneously in order to harmonically vibrate an ulfrasonic member. The present invention is further directed to ulfrasonic soft tissue cutting or coagulating systems in which the ultrasonically vibrating elements undergo non-longitudinal modes of vibration, i.e. vibratory modes for which the direction of the vibrational motion includes at least one component that is non-parallel to the longitudinal axis of the vibrating element. (27) An ultrasonic surgical instrument, constructed in accordance with a preferred embodiment of the present invention, includes an ultrasonic transducer for generating ultrasonic vibrations. An elongated ultrasonic coupler extends along a coupler axis. The ulfrasonic coupler has a proximal end connected to the transducer to receive ultrasonic vibrations therefrom, and a distal end. The ultrasonic coupler is adapted to transmit the ulfrasonic vibrations received at the proximal end to the distal end. A vibration element is connected to the distal end of the coupler for receiving ultrasonic vibrations therefrom so as to undergo vibrational motion.

(28) In one form, the vibration element is formed of a flexible, compliant material, for example a polymer. In one embodiment of the invention, the vibration element has a substantially curvilinear configuration.

(29) In one embodiment, the vibration element is configured so that the direction of the vibrational motion of the vibration element includes at least one component non-parallel to the longitudinal axis.

(30) In one embodiment of the invention, the vibration element is configured so that its vibrational motion is a harmonic superposition of multiple, simultaneous modes of vibration, all of which may be excited by a single mode source.

(31) In one embodiment, the plurality of vibratory modes of the vibration element may include, but is not limited to, transverse modes of vibration, rotational modes of vibration, extensional modes of vibration, bending modes of vibration, and flexural modes of vibration.

(32) In one embodiment, the vibration element is configured so as to yield an extensional vibration coupled with a bending mode, both modes being excited by the extensional source, h this configuration, the bending mode is a harmonic of the extensional wave. This configuration yields an elliptical trajectory for each particle along the working edge of the probe. In this configuration, the equation of the curve for the booster portion of the motion profile is: r = 0.0625 + 0.002 (_e ^{6 Q5χ}-⁶-⁴⁵ - 1),

0.5 < x < 1.0,

where r is the radius of the booster in inches, and x is the distance from the tip in inches.

(33) fri one embodiment of the invention, the vibrational element makes periodic transitions from a substantially compressed first state to a decompressed second state to a substantially stretched third state, while undergoing vibrational motion.

(34) In another form, the present invention is directed to ultrasonic surgical systems that are inexpensive to manufacture and utilize, and include at least one disposable and replaceable component. The costs involved in manufacturing and using the ultrasonic surgical systems are lowered, by avoiding precision-cut component parts.

(35) An ultrasonic surgical system constructed in accordance with the present invention includes an ultrasonic fransducer for converting electric signals into ultrasonic vibrations, and an ulfrasonic transmission coupler connected to the transducer so as to receive the ultrasonic vibrations from the transducer. The transmission coupler is preferably elongated, and is adapted to transmit the ultrasonic vibrations from a proximal end thereof to a distal end thereof. An ultrasonic vibration element is coupled to the distal end of the ultrasonic fransmission coupler. The ulfrasonic vibration element may be a surgical blade, for example.

(36) The ultrasonic surgical system may include an ulfrasonic fransducer sheath for enclosing the ultrasonic transducer. The ultrasonic transmission coupler may also be enclosed within an elongated tubular sheath. (37) In the present invention, at least one of the ulfrasonic fransducer, the ultrasonic transmission coupler, the ultrasonic vibration element, the ultrasonic transducer sheath, and the elongated tubular sheath for enclosing the ultrasonic coupler, is disposable.

(38) In one embodiment, the entire ultrasonic surgical system may be disposable, being formed solely from disposable constituent components.

(39) The ulfrasonic surgical system may be characterized by a resonant frequency. The disposable components may be made of constant cross-section material, and be adapted to have lengths that can be varied so that the resulting ultrasonic surgical system achieves a desired resonant frequency.

(40) Suitable materials for a disposable ultrasonic fransducer may include, but are not limited to, piezoelectric materials, piezoceramic materials, and nickel. Suitable materials for a disposable ultrasonic vibration element (for example a disposable ulfrasonic surgical blade) may include, but are not limited to, plastics, ceramics, polymers, polycarbonates, metals, and plastic-metal alloys.

(41) The ultrasonic surgical system may include a control unit for controlling the amplitude of the ultrasonic vibrations generated by the ulfrasomc surgical system. The control unit may also control the frequency and/or duration of the ultrasonic vibrations. Preferably, the control unit is a hand-controlled unit, and may also be disposable.

BRIEF DESCRIPTION OF THE DRAWINGS

(42) The invention can be more fully understood by referring to the following detailed description taken in conjunction with the accompanying drawings, in which: (43) Fig.1 illustrates an overall schematic view of an ultrasonic surgical system, constructed in accordance with the present invention.

(44) Fig. 2 is a schematic illustration of the velocity distribution and the coupling force distribution resulting from curvilinear and dissimilar configurations of an ultrasonically blade member and a clamp member, in which the geometrical configurations are optimized so as to permit a substantially uniform delivery of ultrasonic power to the tissue.

(45) Fig.s 3 A - 3D illustrate one embodiment of an ultrasonic surgical assembly, in which a ulfrasonic blade member and a receiving clamp member have operative surfaces characterized by curvilinear configurations.

(46) Fig.s 4A - 4C illustrate an ulfrasonic surgical assembly in which a stationary blade member has an operative surface that is substantially convex-shaped.

(47) Fig.s 5A - 5C illustrate an ultrasonic surgical assembly in which a movable blade member has an operative surface that is substantially convex-shaped.

(48) Fig.s 6A - 6D illustrate a scissors-like blade-clamp assembly for an ultrasonic surgical system, in which opposing lateral surfaces of a moveable blade member and a moveable clamp member are adapted for angled interference in response to relative motion therebetween.

(49) Fig. 7 illustrates an ulfrasonic surgical assembly in which the blade member and the clamp member have a serrated configuration.

(50) Fig. 8 schematically illustrates the sinusoidal functions that represent the geometrical variations of the operative surfaces of a blade member and a clamp member that have serrated configurations. (51) Fig. 9 schematically illustrates an ultrasonic surgical assembly in accordance with one embodiment of the present invention, in which the blade member is movable toward the clamp member in a direction parallel to the longitudinal vibrations of the blade member, and no scissors-type mechanism is needed.

(52) Fig. 10 illustrates an overall schematic view of an ultrasonic surgical system, constructed in accordance with the present invention.

(53) Fig. 11 illustrates a probe-jaw assembly for an ultrasonic surgical system constructed in accordance with one embodiment of the present invention, in which the probe member has an operative surface that is substantially convex-shaped with respect to a longitudinal axis thereof, and the clamp jaw has an operative surface that is substantially concave-shaped with respect to a longitudinal axis thereof.

(54) Fig. 12 illustrates another embodiment of a probe-jaw assembly for an ultrasonic surgical system constructed in accordance with one embodiment of the present invention, in which the probe member has an operative surface that is substantially concave-shaped with respect to a longitudinal axis thereof, and the clamp jaw has an operative surface that is substantially convex-shaped with respect to a longitudinal axis thereof.

(55) Fig. 13 illustrates a probe-jaw assembly for an ultrasonic surgical system constructed in accordance with another embodiment of the present invention, in which the ultrasonic probe member is movable in a direction parallel to the longitudinal vibrations.

(56) Fig. 14 illustrates a probe-jaw assembly for an ultrasonic surgical system constructed in accordance with another embodiment of the present invention, in which the ultrasonic probe member can be moved rotatably with respect to the fixed jaw. (57) Fig. 15 illustrates a probe-jaw assembly for an ultrasonic surgical system constructed in accordance with another embodiment of the present invention, in which the ultrasonic probe member can be moved so as to pass through a matching orifice in the fixed jaw.

(58) Fig. 16 illustrates an overall schematic view of an ultrasonic surgical system, constructed in accordance with the present invention.

(59) Fig. 17A illustrates a grasper, constructed according to one embodiment of the present invention, and shown in a retracted state.

(60) Fig. 17B illustrates an extended state of the grasper.

(61) Fig. 17C illustrates the hinge-actuated jaw that closes against the ultrasonic blade, so as to grasp tissue.

(62) Fig. 18 illustrates an overall schematic view of an ultrasonic surgical system, constructed in accordance with the present invention.

(63) Fig.s 19A and 19B illustrate ultrasonic surgical instruments having vibration elements that are configured so as to enable vibration motion that includes a superposition of an extensional mode and a bending mode.

(64) Fig. 20 illustrates an instantaneous longitudinal displacement profile for the surface of a vibration element depicted in Fig.s 19A and 19B, and determined by finite element analysis.

(65) Fig. s 21A - 21E illustrate a vibration element, which undergoes vibrational motion characterized by a periodic variation from a substantially compressed state (Fig. 21A) to an uncompressed state (Fig. 21B), then to a substantially sfretched state (Fig. 21C), then back to the uncompressed state (Fig. 2 ID) and the sfretched state

(Fig. 21E). (66) Fig. 22 illustrates another embodiment of a vibration element, which shows a curved tip tuned for ultrasonic transmission.

(67) Fig. 23 illustrates an overall schematic view of an ulfrasonic surgical system, constructed in accordance with one embodiment of the present invention.

(68) Fig. 24 provides a schematic illustration of an ultrasonic surgical system whose resonant frequency is tunable by varying the length of one or more of its constituent disposable components.

(69) Fig. 25 provides a schematic illustration of an ulfrasomc surgical system having a manually controllable confrol unit for controlling the duration and/or frequency and/or amplitude of the ultrasonic vibrations.

DETAILED DESCRIPTION

(70) Fig. 1 illustrates an overall schematic view of an ultrasonic soft tissue cutting and coagulating system 100, constructed in accordance with one embodiment of the present invention. The system include a handpiece 102 that encloses one or more ulfrasonic transducers 104. An ulfrasonic generator is connected to the handpiece 102, and supplies electric energy. The transducers 104 convert the supplied electric energy into ultrasonic frequency vibratory energy. The frequency range at which the system 100 operates is typically between about 20 kHz and about 100 kHz, and the electric power supplied by the ultrasonic generator is typically between about 100 W to about 150 W, although other frequencies and power levels can be used. The ultrasonic transducers 104 may be made of piezoelectric material, or may be made of other materials, such as nickel, that are capable of converting electric energy into vibratory energy. The handpiece 102 may also enclose an amplifier, for example an acoustic horn, which amplifies the mechanical vibrations generated by the ultrasonic transducers 104.

(71) An elongated ultrasonic fransmission coupler 106 is connected to the handpiece 102. one embodiment, the transmission coupler 106 has a proximal end 108 and a distal end 109, and is connected to the handpiece 102 at the proximal end. The ultrasonic transmission coupler 106 transmits the ultrasonic vibratory energy, received from the transducers 104, from its proximal 108 end to its distal end 109.

(72) In the illustrated embodiment, an ultrasonic surgical assembly 110 is connected to the distal end 109 of the elongated fransmission coupler 106, and includes an ultrasonic blade member 112, and a clamp member 114. In a preferred embodiment, the blade member 112 and the clamp member 114 are movably connected to each other, and cooperate to engage tissue between their respective operative surfaces. In the illustrated embodiment, the blade member 112 is acoustically coupled to the fransmission coupler 106, so that the ultrasonic power is transmitted to, and carried by, the blade member 112. The blade member 112 undergoes vibratory motion upon receipt of ultrasonic vibrations from the transducer(s) 104, and thereby delivers ultrasonic power to contacting tissue, so that desired surgical effects, such as cutting and/or coagulation, can be achieved.

(73) In another embodiment of the invention (not shown), the clamp member 114 may also be acoustically coupled to the transmission coupler 106, so that the ulfrasonic power can also be transmitted to, and carried by, the clamp member 114. In this embodiment, either the blade member 112 or the clamp member 114, or both, may vibrate ulfrasonically.

(74) The blade member 112 and the clamp member 114 may be pivotally mounted at the end of the elongated transmission coupler 106, about a pivot point 116, although in other embodiments of the invention (for example the embodiment illustrated in Figure 8 below), other mechanisms for movably connecting the blade member 112 and the clamp member 114 may be used, the illustrated embodiment illustrated in Figure 1, the surgical assembly 110 is activated by a scissors-like clamp activation mechanism 118.

(75) The ulfrasonic system 100 is generally characterized by a resonant frequency, which is determined primarily by the assembled length of its components. The most efficient vibrations occur when the ultrasonic system 100, including the handpiece 102, the transmission coupler 106, and the surgical assembly 100, is vibrated at its intended resonant frequency. In this case, the maximum vibratory motion occurs at the tip 120 of the blade member 112.

(76) The shape and design of the blade member 112, as well as the clamp member 114, significantly affect the interaction of the ultrasonic surgical system 100 with tissue. In the present invention, at least one of the ultrasonic blade member 112 and the receiving clamp member 114 has a substantially curvilinear configuration. The blade member 112 and the clamp member 114 are movable relative to each other, between an open position in which the blade member 112 and the clamp member 114 are spaced apart, and a closed position in which the blade member 112 and the clamp member 114 are in engagement so as to capture tissue between their respective operative surfaces.

(77) hi a preferred embodiment of the invention, the operative surfaces of the blade member 112 and the receiving clamp member 114 are not only curvilinear, but also dissimilar. In other words, at least portions of the respective operative surfaces of the blade member and the clamp are characterized by substantially different curvature rates.

The spacing between the respective surfaces is non-uniform, and varies over portions of, or over all points between, one end of the surgical assembly 110 to the other. In this description, and henceforth in this specification, the word "dissimilar" is used in the sense of the antonym of "similar," as used when saying that two polygons are not "similar," where a "similar" polygon is generally defined as two polygons whose corresponding angles are congruent, and whose corresponding sides are proportional, as can be found in geometry textbooks.

(78) The curvilinear and dissimilar configurations for the blade member 112 and the clamp member 114 result in several advantageous features for the ultrasonic surgical system 100, as compared to prior art ulfrasonic systems that have linear and/or parallel blade member 112 and clamp member 114. For example, a curvilinear configuration for the blade member 112 and/or clamp member 114 can be optimized so as to produce a substantially uniform distribution of the ultrasonic vibratory energy across the operative surface of the blade member 112. In this way, a substantially uniform cutting/coagulation energy can be delivered along the length of the contact surface with the tissue. The curvilinear configuration can also be optimized so as to achieve a desired spatial distribution of ultrasonic power along the length of the contact surface. Finally, a curvilinear clamp member 114 that is offset and dissimilar to the blade member has, in some forms of the invention, a greater tissue-grasping potential as compared to linear or parallel clamp members known in the prior art.

(79) Fig. 2 is a schematic illustration of the velocity distribution, the coupling force distribution, and the ultrasonic power distribution, which result from an ultrasonic blade member and a clamp member that have curvilinear and dissimilar configurations that are optimized so as to permit a substantially uniform delivery of ulfrasonic power to the tissue. In the illustrated embodiment, the blade member 10 and the clamp member 20 are pivotally mounted about a pivot point 12. hi this embodiment, the ultrasonic vibrations of the blade member 10 are characterized by a resonant frequency at which the maximum vibratory motion occurs at a tip 22 of the blade member 10, and at which a vibratory node occurs at the pivot point 12. The distance between the tip 22

and the pivot point 12 is thus given by (l/4)(λ), where λ represents the wavelength of

the ultrasonic vibrations.

(80) Curves A and B in Fig. 2 schematically represent the curvilinear geometrical configurations of the operative surfaces of the blade member 10 and the clamp member 20, respectively. Curve N(x) in Fig. 2 schematically represents the spatial variation of the transverse velocity of the blade member 20, along its operative surface. Curve C(x) in Fig. 2 schematically represents the ulfrasonic coupling to the tissue being treated, i.e. the mechanical compressive force exerted on the tissue by the operative surfaces of the ultrasonically blade member 10 and the clamp member 20. As seen in Fig. 2, the coupling force C(x) is maximum at the pivot point 12 (i.e. the vibratory node), while the velocity N(x) of the blade member 10 is a minimum at the pivot point 12 and a maximum at the tip 22.

(81) In the present invention, it is recognized that the geometrical variations A and B of the operative surfaces of the blade member 10 and the clamp member 20 can be controlled in such a way that the distribution V(x) of the transverse velocity of blade member 10 along the length of its operative surface can be accounted for. In particular, in the illustrated embodiment the geometrical variations A and B of the operative surfaces of the blade member 10 and the clamp member 20 are made in such a way that the product of 1) the transverse velocity V(x) of the blade member 10 and 2) the mechanical coupling force C(x) is constant, at every point x along the contact surface between the blade member 10 and the tissue. In this way, a substantially uniform distribution of ultrasonic power can be achieved along the entire length of the blade member 10, as shown by curve E(x) = constant, which schematically represents the resulting spatial distribution of ulfrasonic power that is delivered to the contacted tissue.

(82) In an alternative embodiment (not shown), the geometrical variations of the operative surfaces of the blade member and the clamp member can be controlled in such a way that the product of the transverse velocity V(x) of the blade member and the coupling force C(x) has a desired and predetermined spatial dependence along the contact surface between the blade member and the tissue, i.e.:

(velocity N(x) of blade member) * (coupling force C(x) ) = fΕ(x), where fβ(x) represents the spatial distribution of the ultrasonic power delivered to the tissue.

(83) Fig.s 3 A - 3D illustrate one embodiment of a surgical assembly for an ultrasonic system in which both a ultrasonic blade member and a receiving clamp member have operative surfaces characterized by curvilinear configurations. Fig. 3 A provides a side view of the surgical assembly, while Fig. 3B provides an end view thereof, hi the illustrated embodiment, the clamp member is pivotally mounted at the end of a tubular support structure, about a pivot point. The pivot point is shown as being disposed at a location remote from the tip of the ultrasonic blade member. A clamp activator, shown schematically in block diagram form in Fig. 3 A, may be provided in order to activate the pivotally connected blade member and the receiving clamp member.

(84) Fig. 3C illustrates an open-clamp configuration, while Fig. 3D illustrates a closed-clamp configuration, for the surgical assembly illustrated in Fig.s 3 A - 3D. As seen from Fig.s 3C and 3D, the blade member and the clamp member are movably connected, h particular, in the illustrated embodiment the blade member is stationary, while the clamp member is movable from an open position (shown in Fig. 3C) in which the clamp member is spaced apart from the blade member, to a closed position (shown in Fig. 3D) in which the contacting tissue is grasped between the operative surfaces of the blade member and the clamp member.

(85) Fig.s 4A - 4C illustrate a surgical assembly which includes an ultrasonically blade member has a curvilinear operative surface that is substantially convex-shaped, and the clamp member has a curvilinear operative surface that is substantially concave-shaped. As in Fig.s 3A - 3C, the ultrasonic blade member is stationary, while the clamp member is movable. Fig. 4A illustrates a neutral position of the surgical assembly, i.e. a position in which the clamp member is neither maximally spaced apart, nor closed and in engagement against the blade member. Fig. 4B illustrates an open position of the movable clamp member, in which the clamp member is positioned at a location spaced apart from the blade member. Fig. 4C illustrates a closed position of the clamp member, in which tissue can be grasped between the respective operative surfaces of the blade member and the clamp member.

(86) h some surgical procedures, it may be desirable for certain sections of the tissue to receive higher energies, as compared to other sections of the tissue. The ultrasonic vibrational mode along the operative surface of the convex-shaped blade member, illustrated in Fig. 4A - 4C, is less uniform, as compared to ultrasonic modes along the operative surface of a linearly shaped blade member. In the convex-shaped blade member, therefore, the ultrasonic vibrational mode can be such that one or more sections of the operative surfaces of the blade member have a higher energy region, for maximum surgical effect. As discussed in conjunction with Fig. 2, this may be accomplished by controlling the geometric variations of the operative surfaces of the blade member and the clamp member in such a way that

V(x) * C(x) = f_E(x), where V(x) is the transverse velocity distribution of the blade member along the operative surface of the blade member, C(x) is the ulfrasonic coupling force distribution, and fΕ(x) is the desired spatial distribution of ultrasonic power along the length of the contact surface between the tissue and the operative surface of the blade member.

(87) Fig.s 5A - 5C illustrate a surgical assembly in which the ultrasonic blade member has an operative surface that is substantially curvilinear, and is dissimilar to the operative surface of a curvilinear clamp member. As in the embodiment illustrated in Fig.s 3A - 3C, the ultrasonic blade member has an operative surface that is substantially convex-shaped, and the clamp member has an operative surface that is substantially concave-shaped.

(88) In the illustrated embodiment, however, the clamp member is not movable, but stationary, in contrast to the embodiments illustrated in Fig.s 3A-3C, and Fig.s 4A-4C. The ultrasonic blade member is movable between an open position (Fig. 4A), a neutral position (Fig. 4B), and a closed position (Fig. 4C) in which the blade member and the clamp member cooperate to engage tissue between their respective operative surfaces.

(89) Fig.s 6A - 6D illustrate a scissors-like blade-clamp assembly for an ulfrasonic surgical system, in which opposing lateral surfaces of a moveable blade member and a moveable clamp member are adapted for angled interference in response to relative motion therebetween, h the illustrated embodiment, the ultrasonically blade member and the clamp member both have curvilinear operative surfaces.

(90) Fig. 6 A illustrates an open position of the movable blade member and the moveable clamp member, in which the clamp member is positioned at a location spaced apart from the blade member, while Fig. 6B provides an end view thereof.

(91) Fig. 6C illustrates a closed position of the blade member and the clamp member, in which tissue can be grasped between the respective operative surfaces of the blade member and the clamp member, while Fig. 6D provides an end view thereof.

(92) Fig. 7 illustrates a surgical assembly in which the respective operative surfaces of the ultrasonic blade member and the clamp member have a serrated, wavelike configuration. In this embodiment, the operative surface of the blade member may be characterized a substantially sinusoidal configuration, represented by a first sinusoidal wave function fl(x). Likewise, the tissue engaging surface of the clamp member may be characterized by a substantially sinusoidal configuration, represented by a second sinusoidal wave function f2(x). The first sinusoidal wave function and the second sinusoidal wave function may be selected so as to enable a substantially uniform delivery of ulfrasonic power to the tissue, or a delivery of ulfrasonic power according to a desired spatial distribution.

(93) Fig. 8 schematically illustrates the sinusoidal functions that represent the geometrical variations of the respective operative surfaces of a blade member and a clamp member having serrated configurations, as discussed in conjunction with Fig. 6. In an exemplary embodiment illustrated in Fig. 8, curve A represents fl(x), i.e. the sinusoidally varying geometric configuration of the operative surface of the blade member. Curve B represents f2(x), i.e. the sinusoidally varying geometric configuration of the operative surface of the clamp member. In this embodiment, fl(x) and f2(x) may be given, by way of example, by: fl(x) = sin(aωx) + sin(ωx), and

f2(x) = [sin(aωx) + sin(ωx) ] * sin(bωx),

where ω represents the angular frequency of the sinusoidal variations fl(x) and f2(x), and a and b are parameters that represent the transverse distance between the respective operative surfaces of the blade member and the clamp member, at selected points along the distance x that is measured from one end of the surgical assembly to another. By varying the parameters a and b, the geometrical configurations of the serrated operative surfaces of the blade member and the clamp member can be optimized, in order to achieve a desired energy distribution profile.

(94) Fig. 9 schematically illustrates one embodiment of the present invention, in which the blade member 212 and the clamp member 214 are movably connected without being pivotally mounted about a pivot point, and without the need of being activated by a scissors-like clamp activation mechanism. In the illustrated embodiment, the blade member 212 and the clamp member 214 are movable relative to each other in a direction parallel to the longitudinal ultrasonic vibrations of the blade member 212. In particular, the movable blade member 212 is connected to the fixed clamp member 214 so that when the blade member 212 is moved in the direction of the longitudinal vibrations, the blade member 212 aligns against the fixed clamp member 214. In this way, tissue disposed between the movable blade member 212 and the fixed clamp member 214 is compressed as the blade member 212 is moved toward the clamp member 214, and the respective opposing surfaces 222 and 224 of the blade member 212 and the clamp member 214 can be used to grasp tissue therebetween. As in the previously discussed embodiments, the operative surfaces 222 and 224 of the blade member 212 and the clamp member 214 are substantially curvilinear. The operative surfaces 222 and 224 of the blade member 212 and the clamp member 214 are also dissimilar, i.e. at least portions of the respective operative surfaces are characterized by substantially different curvature rates.

(95) Although in the illustrated embodiment, the blade member 212 is movable and the clamp member 214 is fixed, in an alternative embodiment (not shown) the blade member 212 may be fixed, and the clamp member 214 may be movable along the direction of the longitudinal ulfrasonic vibrations.

(96) In sum, by providing an ultrasonic blade member and an opposing clamp member that have substantially curvilinear and dissimilar configurations, the present invention enables soft tissue to be treated evenly across the contact surface, or in accordance with a desired energy distribution profile. The coupling of ultrasonic power to tissue is thereby improved.

(97) Fig. 10 illustrates an overall schematic view of an ultrasonic soft tissue cutting and coagulating system 230, constructed in accordance with the present invention. The system include a handpiece 232, an ultrasonic energy fransmission guide (or horn) 238 covered by a sheath 239, and a tip assembly 240 connecting to a ulfrasonic probe-jaw assembly (shown in Fig.s 11-15), extending from the handpiece

232. An ulfrasonic generator is connected to the handpiece 232, and supplies electric energy. The handpiece 232 encloses one or more ulfrasonic transducers 234, which convert the supplied electric energy into ulfrasonic frequency vibratory energy. The frequency range at which the system operates is typically between about 20 kHz and about 100 kHz, and the electric power supplied by the ulfrasonic generator is typically between about 100 W to about 150 W. The ultrasonic fransducers 234 may be made of piezoelectric material, or may be made of other materials, such as nickel, that are capable of converting electric energy into vibratory energy. The handpiece 232 typically also encloses an amplifier, for example an acoustic horn, that amplifies the mechanical vibrations generated by the ultrasonic transducers. The amplified ulfrasonic energy is transmitted by horn 238 to tip assembly 240.

(98) The ulfrasonic system of the present invention is generally characterized by a resonant frequency, which is determined primarily by the assembled length of its components. The most efficient vibrations occur when the handpiece-probe assembly is vibrated at its intended resonant frequency, in which case the maximum vibratory motion occurs at the tip of the probe.

(99) hi a preferred embodiment of the invention, the system undergoes longitudinal vibratory motion, i.e. the vibrational motion is along an axis passing through the center of the ulfrasonic transducer, the amplifier, and the probe member. The shape and design of the probe member significantly affect the interaction of the ultrasonic surgical system with tissue.

(100) In one embodiment, the system includes a clamp assembly for clamping tissue between a clamping jaw and the horn. In particular, the present invention features a clamp assembly in which the ultrasonic probe member is movable, and the clamp jaw is stationary, in contrast to prior art systems which disclose stationary probe members connected to movable clamp jaws.

(101) In one embodiment, the clamp jaw is pivotally mounted at the end of an elongated tube, and is activated by a scissors-like clamp activation mechanism. (102) Figs. 11 A - 1 ID illustrate a probe-jaw assembly for an ulfrasonic surgical system constructed in accordance with one embodiment of the present invention, which includes a moveable probe member having an operative surface that is substantially convex-shaped with respect to a longitudinal axis ("LA") thereof, and a clamp jaw having an operative surface that is substantially concave-shaped with respect to a longitudinal axis ("LA") thereof, whereby the substantially concave-shaped surface of the clamp jaw receives the substantially convex-shaped surface of the probe member when the probe member is at a closed position, hi the illustrated embodiment, a pivot point is provided for the ultrasonic probe member. The pivot point is disposed at a location remote from the tip of the ulfrasonic probe member.

(103) Fig. 11 A illustrates an open position of the movable probe member, in which the probe member is positioned at a location spaced apart from the clamp member. Fig. 1 IB illustrates a neutral position of the surgical assembly, i.e. a position in which the probe member is neither maximally spaced apart, nor closed and in engagement against the clamp member. Fig. 11C illustrates a closed position of the probe member, in which tissue can be grasped between the respective operative surfaces of the blade member and the clamp member.

(104) Fig. 1 ID illustrates the stationary clamp jaw has a tissue engaging surface. The ulfrasonic probe member is movably and pivotally connected to the clamp jaw. The probe member is movable between an open position spaced from the tissue engaging surface of the clamp jaw, to a clamped position in which the probe member is moved toward the tissue engaging surface so as to capture tissue therebetween. When used as a cutting instrument, the probe member may include a cutting surface that can be moved toward the tissue engaging surface of the stationary clamp jaw, so as to grasp tissue therebetween.

(105) Figs. 12A - 12D illustrate another embodiment of a probe-jaw assembly for an ultrasonic surgical system, which includes a moveable probe member having an operative surface that is substantially concave-shaped with respect to a longitudinal axis ("LA") thereof, and a clamp jaw having an operative surface that is substantially convex-shaped with respect to a longitudinal axis ("LA") thereof, whereby the substantially concave-shaped surface of the probe member receives the substantially convex-shaped surface of the clamp jaw when the probe member is at a closed position.

(106) Fig. 12A illustrates an open position of the movable probe member, in which the probe member is positioned at a location spaced apart from the clamp member, while Fig 12B provides an end view thereof

(107) Fig. 12C illustrates a closed position of the moveable probe member, in which tissue can be grasped between the respective operative surfaces of the blade member and the clamp member, while Fig 12D provides an end view thereof.

(108) Fig. 13 illustrates a probe-jaw assembly for an ultrasonic surgical system constructed in accordance with another embodiment of the present invention, in which the ulfrasonic probe member is movable in a direction parallel to the longitudinal vibrations of the probe. The probe member is connected to a fixed clamp jaw so that when the probe member is moved in the direction of longitudinal vibrations, the probe member aligns in compression against the fixed jaw. fri this way, tissue disposed between the movable probe member and the fixed jaw is compressed, when the horn is moved toward the jaw. (109) Fig. 14 illustrates a probe-jaw assembly for an ulfrasonic surgical system constructed in accordance with another embodiment of the present invention, in which the ultrasonic probe member can be moved rotatably with respect to the fixed jaw. In this embodiment, the clamp jaw is stationary, but can be rotated between a plurality of different positions. After rotating the clamp jaw to a desired position, the ultrasonic probe member can be moved so as to be advanced past the tip of the clamp jaw. The probe member can then be rotated over the fixed clamp jaw.

(110) Fig. 15 illustrates a probe-jaw assembly for an ultrasonic surgical system constructed in accordance with another embodiment of the present invention, in which the ultrasonic probe member can be moved so as to pass through a matching orifice in the fixed jaw. Just as in the embodiment illustrated in Fig. 13 the ultrasonic probe member in the embodiment illustrated in Fig. 15 is movable in a direction parallel to the longitudinal vibrations of the probe, so that tissue disposed between the movable probe member and the fixed jaw is compressed, when the horn is moved toward the jaw. In the embodiment illustrated in Fig. 15, a matching orifice is provided in the receiving clamp jaw, so as to allow the movable ulfrasonic probe member to pass through the orifice in the jaw as the probe member is moved toward the jaw.

(111) By providing an ultrasonically vibrating probe member that is movable with respect to a fixed clamp jaw, the present invention provides an ulfrasonic soft tissue cutting and coagulating system that is more versatile than prior art systems. For example, a wider range of ulfrasonic vibrational frequency can be implemented, to achieve more diverse surgical effects.

(112) In another form, the invention is directed to an ultrasonic surgical system having a retractable grasper that allows an ulfrasonically vibrating member to operate in conjunction with a jaw, without requiring the vibrating member itself to perform a grasping function.

(l'l3) Fig. 16 illustrates an overall schematic view of an ultrasonic soft tissue cutting and coagulating system 300, constructed in accordance with one embodiment of the present invention. The system include a handpiece 302 that encloses one or more ultrasonic transducers 304. An ultrasonic generator is connected to the handpiece 302, and supplies electric energy. The transducers 304 convert the supplied electric energy into ultrasonic frequency vibratory energy. The frequency range at which the system 300 operates is typically between about 20 Hz and about 100 kHz, and the electric power supplied by the ultrasonic generator is typically between about 100 W to about 150 W, although other frequencies and power levels can be used. The ulfrasonic fransducers 304 may be made of piezoelectric material, or may be made of other materials, such as nickel, that are capable of converting electric energy into vibratory energy. The handpiece 302 may also enclose an amplifier, for example an acoustic horn, which amplifies the mechanical vibrations generated by the ulfrasonic transducers 304.

(114) An elongated ultrasonic fransmission coupler 306 is connected to the handpiece 302. In one embodiment, the fransmission coupler 306 has a proximal end 308 and a distal end 309, and is connected to the handpiece 302 at the proximal end. The ulfrasonic transmission coupler 306 transmits the ulfrasonic vibratory energy, received from the transducers 304, from its proximal 308 end to its distal end 309. hi one embodiment, a sheath 390 may enclose the transmission coupler 306.

(115) In the illustrated embodiment, an ulfrasonic surgical assembly 310 is connected to the distal end 309 of the elongated transmission coupler 306, and includes an ulfrasonic blade element 312, and a refractable grasper 313. Preferably, the blade element 312 includes an elongated blade edge 397. The blade element 312 is acoustically coupled to the transmission coupler 306, so that the ultrasonic energy is transmitted to, and carried by, the blade element 312.

(116) The blade element 312 undergoes vibratory motion upon receipt of ulfrasonic vibrations from the transducers) 304. The blade element 312 thereby delivers ulfrasonic energy to the contacting tissue, so that desired surgical effects, such as cutting and/or coagulation, can be achieved, h one form of the invention, the blade element undergoes ulfrasonic vibrations characterized by at least one primary vibratory mode. In one embodiment, the primary vibratory mode may be along a longitudinal direction substantially parallel to the blade edge. The retractable grasper 313 includes a grasping jaw 314, which is operable to close against the blade element 312, so as to engage tissue between their respective operative surfaces.

(117) h one embodiment, the present invention is directed to an accessory for an ulfrasonic surgical instrument having an ultrasonic fransducer for generating ultrasonic vibrations, and an elongated ultrasonic transmission coupler connected to the fransducer to receive ultrasonic vibrations therefrom. The accessory includes a clamp assembly connected to the transducer. The clamp assembly includes a blade element, and a retractable clamp jaw movable relative to the blade element. The clamp jaw is movable from an extended position to a closed position in which the blade element and the clamp jaw are in engagement so as to capture tissue therebetween. The clamp jaw is further movable to a retracted position, suitable for storing the accessory.

(118) Fig.s 17A-17C illustrate a grasper 313, constructed according to one embodiment of the present invention. The grasper 313 is refractable and extendable, i.e. the grasping jaw 314 is movable from an extended position to a closed position in which the blade element and the jaw are in engagement so as to capture tissue therebetween, and is further movable to a retracted position.

(119) The retracted position is shown in Fig. 17 A. When the ultrasonic system 300 is not in use, the grasper 313 can be stored in the retracted position. The grasper 313 in an extended state is illustrated in Fig. 17B. In this configuration, the grasping jaw 314 lies along a horizontal direction substantially parallel to the primary longitudinal mode of vibration of the ulfrasonic blade element.

( 120) Preferably, a j aw activating mechanism is provided for moving the j aw relative to the blade element, from the extended position to the closed position, and again to the refracted position. In one embodiment, the jaw activating mechanism is a hinge, this embodiment, the grasping jaw is hinge-actuated, i.e. is pivotable about a pivot point 396 from an open position to a closed position in which the jaw closes against the ultrasonic blade so as to grasp tissue therebetween, and subsequently to a retracted position, for storage. In the extended state, the pivot point 396 is preferably aligned with the elongated edge 397 of the ultrasonic blade, and the grasping jaw 314 extends beyond the elongated edge, along the horizontal direction.

(121) The jaw 314 is operable to move, in a direction substantially perpendicular to the primary vibratory mode of the ulfrasonic blade, from the open, extended position described above to a closed position illustrated in Fig. 17C. Fig. 17C illustrates the hinge-actuated jaw that closes against the ultrasonic blade, so as to grasp tissue. As seen in Fig. 17C, the jaw closes against the blade in a direction substantially parallel to the direction of the ultrasonic vibrations. The tissue being treated is thereby grasped, between the jaw and the blade. In this way, tissue can be grasped, without requiring the ultrasonic blade by itself to perform a grasping function. (122) Another form of the present invention features a "multiple-wavelength" ultrasonic probe, having a vibrational element configured to support vibrational modes that are a superposition of a plurality of different modes of vibration, thereby enabling the simultaneous activation of multiple modes, hi particular, the present invention is directed to intentional stimulation of vibrational motion that is perpendicular to the longitudinal axis of the ulfrasonic probe. By stimulating transverse and/or rotational modes of vibration, the total vibration of the ulfrasonic element is intentionally amplified.

(123) Fig. 18 illustrates an overall schematic view of an ultrasonic surgical system 400, constructed in accordance with the present invention. The system 400 includes at least one ultrasonic transducer 404. An ultrasonic generator is connected to the transducer 404, and supplies electric energy. The ultrasonic transducer 404 converts the supplied electric energy into ulfrasonic frequency vibratory energy. The frequency range at which the system operates is typically between about 20 kHz and about 100 kHz, and the electric power supplied by the ultrasonic generator is typically between about 100 W to about 150 W. The ulfrasonic transducer 404 maybe made of piezoelectric material, or may be made of other materials, such as nickel, that are capable of converting electric energy into vibratory energy. The system may also include an amplifier (for example an acoustic horn), which amplifies the mechanical vibrations generated by the ultrasonic fransducers.

(124) The system includes an elongated ultrasonic fransmission coupler 406 that extends along a coupler axis and has a proximal end 408 and a distal end 409. The ulfrasonic coupler 406 is connected at the proximal end 408 to the fransducer 404 to receive ultrasonic vibrations therefrom. The ultrasonic coupler 406 is adapted to transmit the ulfrasonic vibrations received at the proximal end 408 to the distal end 409.

(125) A vibration element 420 is connected to the distal end of the coupler, and receives ulfrasonic vibrations from the coupler 406 so as to undergo vibrational motion. In an embodiment in which the vibration element 420 is used for cutting tissue, the vibration element 420 may be in the form of a blade, preferably having a blade edge 422 parallel to the coupler axis. In one embodiment of the invention, the vibration element is formed of a flexible, compliant material, for example a polymer. Examples of compliant materials that can be used to make the vibration element include, but are not limited to, polymer materials.

(126) In one form of the invention, the vibration element has a substantially curvilinear configuration.

(127) In the present invention, the vibration element 420 is configured in such a way that the vibrational motion of the vibration element is a superposition of a plurality of vibratory modes. In a preferred embodiment of the invention, the vibration element 420 is configured so as to enable the simultaneous use of multiple modes of vibration to harmonically vibrate the vibration element 420. h one form, these multiple modes of vibration may all be excited by a single mode source. The individual constituent vibratory modes may include, but are not limited to, extensional modes of vibration, bending modes of vibration, flexural modes of vibration, transverse modes of vibration, and rotational modes of vibration.

(128) Preferably, the vibration element 420 is configured so that the direction of the vibrational motion of the vibration element includes at least one component non- parallel to the coupler axis, i.e. the vibratory modes of the vibration element include non- longitudinal modes of vibration.

(129) In a preferred embodiment of the invention, transverse and/or rotational modes of vibration are stimulated. In other words, the plurality of vibratory modes forming the composite mode of vibration of the vibration element includes 1) at least one transverse mode generated by a motion perpendicular to the longitudinal axis of the ultrasonic probe, and 2) at least one rotational mode generated by a rotational motion about the longitudinal axis.

(130) Fig.s 19A and 19B illustrate ulfrasonic surgical systems 500 and 501, which are constructed according to the preferred embodiment of the invention. In the illusfrated embodiment, The vibration elements 520 and 521 are configured so as to amplify total vibration by stimulating transverse and/or rotational motion, h other words, motion of the vibrational element that is either perpendicular to the longitudinal axis (shown in Fig.s 19A and 19B as 530) of the systems 500 and 501, or is rotational about the axis 530, is intentionally stimulated.

(131) The configurations of the vibrational elements in Fig.s 19A and 19B were designed to yield an extensional vibration, coupled with a bending mode. Both modes were excited by a single source, namely the extensional source. In the illusfrated embodiment, the bending modes was not of the same wavelength as the extensional mode, but was a harmonic of the extensional mode. The design shown in the illustrated embodiments results from iterative methods, using finite element modal analysis, h other embodiments of the invention, the designs of the vibrational elements may be accomplished by trial and error, and by testing. As indicated hi Fig.s 19A and 19B, the material from which the surgical systems 400 and 401 are fabricated is a titanium - aluminum alloy, more precisely Ti 6 Al - 4V ELI.

(132) The vibration elements 520 and 521 each include a tip 550 and 551, respectively. The vibration elements 520 and 521 also include at least one operative edge 552 and 553, respectively, along at least one side thereof. In the illustrated embodiment, the equation of the curve for the booster portion of the motion profile was: r = 0.0625 + 0.002 (_e ⁶-^95χ-⁶-⁴⁵ - 1),

0.5 < x < 1.0,

where r is the radius of the booster in inches, and x is the distance from the tip in inches. The resulting trajectory for each particle along the operative edges 552 and 553 of the vibration elements 520 and 521 is an elliptical trajectory.

(133) As seen from Figs. 19A and 19B, the length of both the ulfrasonic surgical systems 500 and 501, as measured from the proximal end 508 of the fransmission coupler 506 to the distal tip of the vibration element, is about 2.800 inches. The vibration element 520 of the surgical system 500 has a booster radius of 0.044 inches, and a 45 degree chamfer at the distal tip of the vibration element. The width of the vibration element is 0.038 inches. The vibration element 521 of the surgical system 501 has a shape similar to a knife blade. The tapered portion of the vibration element 521 has a length of 0.239 inches. The booster radius of the surgical system 501 is 0.277 inches.

(134) In the illusfrated embodiments, transverse and/or rotational vibrational modes were stimulated, so as to develop a multi-dimensional velocity vector on the operative edge of the vibrational element. The resultant vector is time varying, and varies as a function of its position along the operative edge, to yield a time and position dependent velocity profile.

(135) Fig. 20 illustrates velocity and displacement profiles for the surface of a exemplary vibration element that undergoes a vibrational motion consisting of a superposition of a extensional mode and a bending mode, as discussed in conjunction with Fig.19. The curves shown in Fig. 20 were determined by finite element analysis, at a frequency of 75856 Hz.

(136) The solid curve 600 shown in Fig. 20 illustrates the instantaneous longitudinal displacement profile, hence the velocity profile, of the surface of the vibration element depicted as 521 in Fig.s 19A and 19B. The instantaneous longitudinal displacement (not to scale) is shown as a function of the distance from the distal end of the probe, in inches. The instantaneous transverse displacement of the surface of the vibration element 521 is also shown, as a dotted curve 601, also as a function of the distance from the distal end of the probe. The superposition of 600 and 601, which is the resultant magnitude of the instantaneous displacement for the vibration element, is shown as a dashed curve 602, and is indicated in Fig. 20 as "Superposition of Both." The resulting composite surface displacement curve (i.e. the dashed curve 602) is also shown as a function of the distance from the end of the probe. As discussed in conjunction with Fig.s 19A and 19B, the resulting trajectory for each particle along the working edge of the vibration element is an elliptical trajectory.

(137) Figures 21A - 21E illustrates another embodiment of the present invention, in which the vibrating element undergoes vibrational motion characterized by a periodic variation from a substantially compressed state to an uncompressed (or de- compressed) state to a substantially sfretched state of the vibration element, upon receipt of ultrasonic vibrations transmitted through the coupler.

(138) Figure 21A illustrates the initial, substantially compressed state of the vibration element in the embodiment illustrated in Figs. 21 A - 21E. Figure 21B illustrates the subsequent de-compressed state of the vibration element. Figure 21C illustrates the maximum sfretched state of the vibration element. Figure 2 ID illustrates the vibration element returning to an unstretched, and uncompressed state. Figure 2 IE illustrates the final, substantially compressed state of the vibration element.

(139) The modes of vibration illustrated in Fig.s 21 A - 21E may be formed, in one embodiment of the invention, by combimng a longitudinal mode of vibration, with a torsional or twisting mode of vibration. Alternatively, the illustrated modes of vibration may be formed by combining a longitudinal mode of vibration with a flexural mode of vibration. Alternatively, the illustrated modes of vibration may be formed by combining a longitudinal mode of vibration with a rotational mode of vibration.

(140) When the vibration element undergoes longitudinal modes of vibration, the vibration element moves back and forth along the longitudinal axis parallel to the coupler axis. By compounding the longitudinal modes with the torsional, flexural, or rotational modes, the vibration element undergoes the trajectory shown schematically in Fig.s 21 A - 21E as it moves from the substantially compressed state to the decompressed stated to the substantially stretched state, then back to the substantially compressed state.

(141) Fig. 22 illustrates another embodiment of a vibration element, which has a curved tip 622 tuned for ultrasonic transmission. Preferably, the curve is tuned to transmit maximal amplitude vibration at the tip 622. (142) Yet another form of the present invention features ultrasonic surgical systems that include at least one disposable component part. The disposable component parts may include, but are not limited to, an ulfrasonic transducer, an ultrasonic fransmission coupler, an ulfrasonic vibration element (for example an ulfrasonic surgical blade), and an ultrasonic transducer sheath. By using disposable component parts that are replaceable after use, and that are not precision-cut, the ulfrasonic surgical systems of the present invention are much more economical to produce and to utilize, as compared to prior art ulfrasonic surgical systems.

(143) Fig. 23 illustrates an overall schematic view of an ultrasonic surgical system 700, constructed in accordance with one embodiment of the present invention. The system 700 includes an ulfrasonic transducer sheath 702 that encloses one or more ultrasonic transducers 704. An ultrasonic generator is connected to the transducer sheath 702, and supplies electric energy. The transducers 704 convert the supplied electric energy into ultrasonic frequency vibratory energy. The frequency range at which the system 700 operates is typically between about 20 kHz and about 100 kHz, and the electric power supplied by the ulfrasonic generator is typically between about 100 W to about 150 W, although other frequencies and power levels can be used. The ultrasonic fransducers 704 may be made of piezoelectric material, or may be made of other materials, such as nickel, that are capable of converting electric energy into vibratory energy. The fransducer sheath 702 may also enclose an amplifier, for example an acoustic horn, which amplifies the mechanical vibrations generated by the ultrasonic fransducers 704.

(144) An elongated ultrasonic transmission coupler 706 is connected to the fransducer sheath 702. h one embodiment, the fransmission coupler 106 has a proximal end 708 and a distal end 709, and is comiected to the transducer sheath 702 at the proximal end. The ultrasonic transmission coupler 706 transmits the ultrasonic vibratory energy, received from the transducers 704, from its proximal 708 end to its distal end 709. h one embodiment, a tubular sheath 790 may enclose the transmission coupler 706.

(145) hi the illusfrated embodiment, an ulfrasonic vibration element 710 is connected to the distal end 709 of the elongated fransmission coupler 706. The ulfrasonic vibration element 710 has the form and shape of an ultrasonic surgical blade, although in other embodiments of the invention, the ulfrasonic vibration element 710 may take other forms and shapes. The vibration element 710 is acoustically coupled to the transmission coupler 706, so that the ultrasonic energy is transmitted to, and carried by, the vibration element 710. The vibration element 710 undergoes vibratory motion upon receipt of ultrasonic vibrations from the fransducer(s) 704. The vibration element 710 thereby delivers ulfrasonic energy to the contacting tissue, so that desired surgical effects, such as cutting and/or coagulation, can be achieved.

(146) In the present invention, at least one of the ulfrasonic transducer 704, the ulfrasonic fransmission coupler 706, and the ulfrasonic vibration element 710, is disposable. By using inexpensive, disposable component parts, the cost of manufacturing and utilizing the ulfrasonic surgical system 700 is significantly lowered, as compared to prior art devices.

(147) fri some embodiments of the invention, the ulfrasonic transducer sheath, and the tubular sheath enclosing the ultrasonic fransmission coupler, are also disposable.

In one embodiment, the entire ulfrasonic surgical system 700 may be disposable, being composed wholly of disposable parts. In this embodiment, each and every one of the ultrasonic fransducer 704, the ulfrasonic transmission coupler 706, the ulfrasomc vibration element 710, and the ultrasonic transducer sheath, are disposable.

(148) In order to manufacture disposable component parts, the appropriate constituent material must be chosen for each disposable component part. In an embodiment in which the ultrasonic surgical system 700 includes a disposable ulfrasonic fransducer, the ulfrasonic transducer may be made of one of the following materials: piezoelectric materials, piezoceramic materials, and nickel, fri an embodiment in which the ulfrasonic surgical system 700 includes a disposable ulfrasonic vibration element, for example a disposable ultrasonic surgical blade, the materials with which the disposable vibration elements may be formed include the following: plastics, ceramics, polymers, polycarbonates, metals, and plastic-metal alloys.

(149) fri the present invention, the disposable component parts are not precision- cut. Rather, the disposable component parts are press-fit, or "snapped on" to each other, so as to form the final surgical assembly. For example, in an embodiment in which the ultrasonic surgical system includes an ultrasonic transducer sheath, and a disposable ulfrasonic fransducer, the fransducer is adapted to be press-fit within the transducer sheath. Similarly, in an embodiment in which the ultrasonic surgical system includes a tubular sheath for enclosing the ulfrasonic transmission coupler, the fransmission coupler is adapted to be press-fit within the tubular sheath.

(150) Alternatively, the disposable component parts may be threaded, so that each disposable component part can be screwed onto its connecting element. Alternatively, the component parts of the surgical system may be adapted to be connected to each other via a spring mechanism. (151) Because the component parts are disposable, and not precision-cut, the ultrasonic surgical system of the present invention can accommodate a greater tolerance range, as compared to surgical systems having precision-cut components. Rough, rather than precise, tolerances can be accomodated.

(152) An ultrasonic surgical system, such as the system described above in conjunction with Fig. 23, has a resonant frequency that is determined primarily by the assembled length of its components. Although the ultrasonic surgical system 700, which may be viewed as forming an acoustic assembly, may be vibrated at almost any frequency, efficient and useful vibration occurs only when the acoustic assembly is vibrated at its intended resonant frequency, fri this case, maximum vibratory motion occurs at the tip of the vibrating element, with relatively little input power from the ulfrasonic generator.

(153) In the present invention, the resonant frequency of the system can be tuned, by varying the lengths of the disposable components until the desired resonant frequency is reached. Fig. 24 provides a schematic illustration of an ultrasonic surgical system whose resonant frequency is tunable by varying the length of one or more of its constituent disposable components.

(154) h order to keep costs down, no specific features (such as specific desired frequencies of vibration) are incorporated by precision-cutting the components. Rather, a constant cross-section material that is suitable for a disposable component part is chosen, then the ultrasonic system is tuned until the desired resonant frequency for the system is reached.

(155) The ultrasonic surgical system of the present invention may include a confrol unit for controlling the amplitude of the ulfrasonic vibrations. Preferably, the control unit is manually controllable, i.e. is a hand-controlled unit. The control umt may also control the frequency and/or duration of the ultrasonic vibrations. Fig. 25 provides a schematic illustration of an ulfrasonic surgical system having a control unit for controlling the duration and/or frequency and/or amplitude of the ulfrasonic vibrations. As illusfrated in Fig. 25, the control unit is connected to the ultrasonic transducer. In one embodiment, the control unit may also be disposable.

(156) hi sum, the present invention features an inexpensive ultrasonic surgical system that includes one or more disposable and replaceable component parts that are assembled by press- fitting each component to each other.

(157) While the invention has been particularly shown and described with reference to specific preferred embodiments, it should be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims

What is claimed is:

1. An ultrasonic surgical instrument, comprising: a. an ultrasonic transducer for generating ultrasonic vibrations; b. an elongated ulfrasonic transmission coupler having a proximal end and a distal end and connected to said transducer at said proximal end, said coupler being adapted to receive ultrasonic vibrations at said proximal end and transmit said ulfrasonic vibrations to said distal end; c. an ulfrasonic surgical assembly connected to said distal end of said coupler, said ulfrasonic surgical assembly including a blade member and a clamp member movable relative to each other from an open position in which the blade member and the clamp member are spaced apart, to a closed position in which the blade member and the clamp member are in engagement so as to capture tissue therebetween; wherein at least one of said blade member and said clamp member are characterized by a substantially curvilinear configuration.

2. -An ultrasonic surgical instrument according to claim 1, wherein said blade member is acoustically coupled to said ulfrasonic coupler for receiving ultrasonic vibrations therefrom so as to undergo vibratory motion, thereby permitting ulfrasonic power to be delivered to tissue in contact with said blade member.

3. An ultrasonic surgical instrument according to claim 1, wherein said blade member is rigidly attached to said coupler, and said clamp member is movably attached to said coupler and is movable toward said rigidly attached blade member from said open position to said closed position.

4. An ultrasonic surgical instrument according to claim 1, wherein said clamp member is rigidly attached to said coupler, and said blade member is movably attached to said coupler and is movable toward said rigidly attached clamp member from said open position to said closed position.

5. An ultrasonic surgical instrument according to claim 1, wherein said blade member has an operative surface characterized by a first curvature rate, and wherein said clamp member has an operative surface characterized by a second curvature rate.

6. An ulfrasonic surgical instrument according to claim 5, wherein said first curvature rate and said second curvature rate are substantially different.

7. -An ultrasonic surgical instrument according to claim 1, wherein said blade member includes an operative surface characterized a substantially sinusoidal configuration represented by a first sinusoidal wave function; and wherein said operative surface of said clamp member is characterized by a substantially sinusoidal configuration represented by a second sinusoidal wave function.

8. An ultrasonic surgical instrument according to claim 1, wherein opposing lateral surfaces of said blade member and said clamp member are adapted for angled interference in response to relative motion therebetween.

9. An ultrasonic instrument for cutting tissue, comprising: a. an ulfrasonic fransducer for generating ulfrasonic vibrations; b. a probe member coupled to said ultrasonic transducer for receiving ulfrasonic vibrations therefrom; and c. a stationary clamp jaw having a tissue engaging surface; wherein said probe member is movably connected to said clamp jaw; and wherein said probe member includes a cutting surface movable between an open position spaced from the tissue engaging surface of the clamp jaw, to a clamped position in which the cutting surface is moved toward the tissue engaging surface so as to capture tissue therebetween.

10. An ulfrasonic instrument for coagulating tissue, comprising: a. an ulfrasonic fransducer for generating ultrasonic vibrations; b. a probe member connected to said ulfrasonic transducer for receiving ultrasonic vibrations therefrom; and c. a stationary clamp jaw having a tissue engaging surface; wherein said probe member is movably connected to said clamp jaw; and wherein said probe member is movable between an open position spaced from the tissue engaging surface of the clamp jaw, to a clamped position in which the probe member is moved toward the tissue engaging surface so as to capture tissue therebetween.

11. An ultrasonic surgical instrument, comprising: a. an ulfrasonic transducer for generating ultrasonic vibrations; b. a grasper assembly connected to said fransducer, said grasper assembly including: i) a blade element; and ii) a grasping j aw movable relative to said blade element, said j aw being movable from an extended position to a closed position in which the blade element and the jaw are in engagement so as to capture tissue therebetween, said jaw being further movable to a retracted position.

12. An ultrasonic surgical instrument according to claim 11, wherein said blade element has an elongated blade edge.

13. An ultrasonic surgical instrument according to claim 11 , wherein said blade is coupled to said transducer for receiving ulfrasonic vibrations therefrom so as to undergo ulfrasonic vibrations characterized by at least one primary vibratory mode.

14. An ultrasonic surgical instrument according to claim 12, wherein said blade element is coupled to said fransducer for receiving ulfrasonic vibrations therefrom so as to undergo ultrasonic vibrations characterized by at least one primary vibratory mode; and wherein said primary vibratory mode is along a longitudinal direction substantially parallel to said blade edge.

15. An ultrasonic surgical instrument according to claim 14, wherein said jaw is movable relative to said blade element in a direction substantially perpendicular to said primary vibratory mode.

16. An ultrasonic surgical instrument according to claim 11, further comprising a jaw activating mechanism for moving said jaw relative to said blade element from said extended position to said closed position, and from said extended position to said refracted position.

17. An ultrasonic surgical instrument according to claim 16, wherein said jaw activating mechanism comprises a hinge that actuates the motion of the jaw from said extended position to said closed position, and from said extended position to said retracted position.

18. An accessory for an ultrasonic surgical instrument having an ulfrasomc fransducer for generating ultrasonic vibrations, and an elongated ultrasonic transmission coupler connected to said fransducer and adapted to receive ulfrasonic vibrations therefrom and transmit said vibrations from one end of said coupler to the other end, said accessory comprising: a. a clamp assembly connected to said fransducer, said clamp assembly including: i) a blade element; and ii) a retractable clamp jaw movable relative to said blade element, said clamp jaw being movable from an extended position to a closed position in which the blade element and the clamp jaw are in engagement so as to capture tissue therebetween.

19. An ultrasonic surgical instrument, comprising: a. an ulfrasonic fransducer for generating ultrasonic vibrations; b. an ultrasonic transmission coupler extending along a coupler axis and having a proximal end and a distal end, said ultrasonic coupler being connected at said proximal end to said fransducer to receive ultrasonic vibrations therefrom, said ulfrasonic coupler being adapted to fransmit the ulfrasonic vibrations received at said proximal end to said distal end; and c. a surgical assembly connected to said distal end of said coupler, said surgical assembly including a ; wherein said vibration element is configured so that the direction of said vibrational motion of said vibration element includes at least one component non- parallel to said coupler axis.

20. An ultrasonic surgical instrument according to claim 19, wherein said vibrational motion of said vibration element comprises a superposition of a plurality of vibratory modes.

21. An ultrasonic surgical instrument according to claim 19, wherein said plurality of vibratory modes comprises at least one bending mode of vibration.

22. An ulfrasonic surgical instrument according to claim 19, wherein said plurality of vibratory modes comprises at least one extensional mode of vibration.

23. An ultrasonic surgical instrument according to claim 19, wherein said vibration element is formed of a compliant material.

24. An ultrasonic surgical instrument according to claim 19, wherein said compliant material comprises polymeric material.

25. An ultrasonic surgical instrument according to claim 24, wherein said vibrational motion of said vibration element is characterized by a periodic variation in the state of said element from a substantially compressed first state to a substantially stretched second state.

26. -An ultrasonic surgical instrument according to claim 19, wherein said vibration element is characterized by a substantially curvilinear configuration.

27. -An ulfrasonic surgical instrument, comprising: a. an ulfrasonic fransducer for generating ultrasonic vibrations; b. an ultrasonic coupler extending along a longitudinal axis, said coupler having a proximal end connected to said fransducer to receive ultrasonic vibrations therefrom, said coupler being adapted to fransmit the ultrasonic vibrations from said proximal end to a distal end of said coupler; and c. a vibration element connected to said distal end of said coupler for receiving ultrasonic vibrations therefrom so as to undergo vibrational motion; wherein said vibrational motion of said vibration element comprises a superposition of a plurality of vibratory modes; and wherein said plurality of vibratory modes comprises at least one transverse mode that is generated by a motion perpendicular to said longitudinal axis.

28. -An ultrasonic surgical instrument according to claim 27, wherein said plurality of vibratory modes comprises at least one extensional mode and at least one bending mode.

29. An ultrasonic surgical instrument according to claim 28, wherein said bending mode is a harmonic of said extensional mode.

30. -An ultrasonic surgical instrument according to claim 29, wherein said vibration element comprises an operative edge, and wherein the trajectory undertaken by each particle along said operative edge as a result of said vibrational motion of said vibration element is substantially elliptical.

31. An ulfrasonic surgical instrument according to claim 27, wherein said vibration element comprises an operative edge along one side thereof.

32. An ultrasonic surgical instrument according to claim 31, wherein said operative edge is characterized by a velocity profile generated as a result of said vibrational motion.

33. An ulfrasonic surgical instrument according to claim 32, wherein said velocity profile is time dependent.

34. An ulfrasonic surgical instrument according to claim 33, wherein said velocity profile is position dependent.

35. An ulfrasonic surgical instrument according to claim 27, wherein said vibration element comprises a tip.

36. -An ulfrasonic surgical instrument according to claim 27, wherein said vibration element is characterized by a profile whose equation of curve for the booster portion is given by: r = 0.0625 + 0.002 (_e ⁶-^95χ-⁶-⁴⁵ - 1),

0.5 < x ≤ 1.0,

where r is the radius of the booster in inches, and where x is the distance from said tip in inches.

37. An ulfrasonic surgical instrument according to claim 27, wherein the configuration of said vibration element is developed using finite element modal analysis.

38. An ultrasonic surgical instrument, comprising: a. an ultrasonic fransducer for generating ulfrasonic vibrations; b. an ultrasonic coupler extending along a longitudinal axis, said coupler having a proximal end connected to said fransducer to receive ulfrasonic vibrations therefrom, said coupler being adapted to transmit the ulfrasonic vibrations from said proximal end to a distal end of said coupler; and c. a vibration element connected to said distal end of said coupler for receiving ultrasonic vibrations therefrom so as to undergo vibrational motion; wherein said vibrational motion of said vibration element comprises a superposition of a plurality of vibratory modes; and wherein said plurality of vibratory modes comprises at least one rotational mode that is generated by a rotational motion about said longitudinal axis.

39. An ulfrasonic surgical instrmnent according to claim 24, wherein said vibrational motion of said vibration element is characterized by a periodic variation from a substantially compressed first state of said element to a de-compressed second state of said element to a substantially stretched third state of said element.

40. An ultrasonic surgical system, comprising: a. an ultrasonic fransducer for converting electric signals into ulfrasonic vibrations; b. an ultrasonic fransmission coupler connected to said transducer so as to receive said ulfrasonic vibrations therefrom, said coupler being adapted to fransmit said ulfrasonic vibrations from a proximal end thereof to a distal end thereof; c. an ulfrasonic vibration element coupled to said distal end of said ultrasonic transmission coupler; wherein at least one of said ulfrasonic transducer, said ultrasonic transmission coupler, and said ultrasonic vibration element is disposable.

41. An ultrasonic surgical system according to claim 40, wherein said ulfrasonic transducer is disposable, and wherein said ultrasonic fransducer comprises at least one of a piezoelectric material, a piezoceramic material, and nickel.

42. An ulfrasonic surgical system according to claim 41, wherein said ulfrasonic fransducer is adapted to be press-fit onto said ulfrasonic transmission coupler.

43. An ultrasonic surgical system according to claim 40, wherein said ultrasonic vibration element comprises a surgical blade.

44. An ulfrasonic surgical system according to claim 40, wherein said ultrasonic vibration element is disposable, and wherein said ultrasonic vibration element comprises at least one of a plastic material, a ceramic material, a polymer material, a polycarbonate material, a metal, and a plastic-metal alloy.

45. An ulfrasonic surgical system according to claim 44, wherein said ultrasonic surgical system is characterized by a resonant frequency.

46. An ultrasonic surgical system according to claim 40, further comprising an ulfrasonic transducer sheath for enclosing said ultrasonic fransducer.

47. An ulfrasonic surgical system according to claim 46, wherein said ultrasonic transducer sheath is disposable.

48. An ulfrasonic surgical system according to claim 47, wherein said ultrasonic transducer is disposable, and wherein said ultrasonic transducer is adapted to be press-fit onto said ultrasonic fransducer sheath.

49. An ulfrasonic surgical system according to claim 40, further comprising an tubular sheath for enclosing said ulfrasonic transmission coupler.

50. An ulfrasonic surgical system according to claim 49, wherein said tubular sheath is disposable.

51. An ulfrasonic surgical system according to claim 40, further comprising a confrol unit for controlling at least one of the duration, frequency, and amplitude of said ultrasonic vibrations.

52. An ulfrasonic surgical system according to claim 51, wherein said confrol unit is manually controllable.

53. An ultrasonic surgical system according to claim 52, wherein said confrol unit is disposable.

54. An ulfrasonic surgical system according to claim 40, wherein each of said ulfrasonic fransducer, said ultrasonic vibration element, and said ultrasonic fransmission coupler is disposable.

55. An ultrasonic surgical system according to claim 40, wherein at least one of said ultrasonic fransducer, said ultrasonic fransmission coupler, and said ulfrasonic vibration element is a tunable-length device for which the length is adapted to be varied so as to tune said surgical system to a predetermined resonant frequency.

56. An ulfrasonic surgical system according to claim 40, wherein said ulfrasonic vibration element is disposable, and is coupled to the ulfrasonic transmission coupler via a spring mechanism.

57. An ulfrasonic surgical system according to claim 40, wherein at least one of said ulfrasonic fransducer, said ulfrasonic vibration element, and said ultrasonic fransmission coupler is fabricated from a constant cross-section material.