Patent Abstract:
An improved ultrasonic surgical apparatus includes an ultrasonic handpiece. An ultrasonic fragmenting tool is mountable within the handpiece, the tool having a vibratable tip adapted for ultrasonically fragmenting tissue at a surgical site of a patient. A transducer is mounted within the handpiece and coupled to a connector body. The connector body is coupled to the tip for transmitting ultrasonic waves to the tip from the transducer, the tip and the connector body being constructed of titanium or its alloys. An aspirating system is connected to the handpiece for aspirating fluid and tissue fragmented by the tip from the surgical site. An irrigation system is connected to said handpiece for supplying irrigation fluid to the surgical site for suspending fragmented tissue by the tip. Preferred embodiments include operational frequencies of about 36 kHz.

Full Description:
This application claims benefit to U.S. provisional application Ser. No. 60/101,702 filed Sep. 25, 1998. 
    
    
     BACKGROUND 
     1. Technical Field 
     This disclosure relates to surgical systems and, more particularly to an improved ultrasonic surgical apparatus for ultrasonically fragmenting tissue. 
     2. Background of Related Art 
     Devices which effectively utilize ultrasonic energy for a variety of applications are well-known in a number of diverse arts. The application of ultrasonically vibrating surgical devices used to fragment and remove unwanted tissue with significant precision and safety has led to the development of a number of valuable surgical procedures. Accordingly, the use of ultrasonic aspirators for the fragmentation and surgical removal of tissue from a body has become known. Initially, the technique of surgical aspiration was applied for the fragmentation and removal of cataract tissue. Later, such techniques were applied with significant success to neurosurgery and other surgical specialties where the application of ultrasonic technology through a handheld device for selectively removing tissue on a layer-by-layer basis with precise control has proven feasible. 
     Certain devices known in the art characteristically produce continuous vibrations having a substantially constant amplitude at a predetermined frequency (i.e 20-30 kHz). Certain limitations have emerged in attempts to use such devices in a broad spectrum of surgical procedures. For example, the action of a continuously vibrating tip may not have a desired effect in breaking up certain types of body tissue, bone, etc. Because the ultrasonic frequency is limited by the physical characteristics of the handheld device, only the motion available at the tip provides the needed motion to break up a particular tissue. The limited focus of such a device may render it ineffective for certain applications due to the vibrations which may be provided by the handheld device. For certain medical procedures, it may be necessary to use multiple hand held devices or it may be necessary to use the same console for powering different handheld devices. 
     Certain devices known in the art characteristically produce continuous vibrations having a substantially constant amplitude at a frequency of about twenty to about thirty kHz up to about forty to about fifty kHz. The amplitude is inversely proportional to frequency and directly proportional to wavelength. U.S. Pat. Nos. 4,063,557, 4,223,676 and 4,425,115 disclose devices suitable for the removal of soft tissue which are particularly adapted for removing highly compliant elastic tissue mixed with blood. Such devices are adapted to be continuously operated when the surgeon wishes to fragment and remove tissue, and generally is operated by a foot switch. 
     A known instrument for the ultrasonic fragmentation of tissue at an operation site and aspiration of the tissue particles and fluid away from the site is the CUSA model System 200 Ultrasonic Aspirator manufactured and sold by Valleylab, Inc. of Boulder, Colo., a subsidiary of U.S. Surgical Corporation; see also U.S. Pat. No. 4,827,911. When the longitudinally vibrating tip in such an aspirator is brought into contact with tissue it gently, selectively and precisely fragments and removes the tissue. Advantages of this unique surgical instrument include minimal damage to healthy tissue in a tumor removal procedure, skeletoning of blood vessels, prompt healing of tissue, minimal heating or tearing of margins of surrounding tissue, with minimal pulling of healthy tissue, and excellent tactile feedback for selectively controlled tissue fragmentation and removal is provided. 
     In many surgical procedures where ultrasonic fragmentation instruments are employed additional instruments are required for tissue cutting and hemostasis at the operation site. For example, hemostasis is needed in desiccation techniques for deep coagulation to dry out large volumes of tissue and also in fulguration techniques for spray coagulation to dry out the surface of tissues. 
     The apparatus disclosed in U.S. Pat. Nos. 4,931,047 and 5,015,227 provide hemostasis in combination with an ultrasonically vibrating surgical fragmentation instrument and aspirator. The apparatus effectively provide both a coagulation capability and an enhanced ability to fragment and aspirate tissue in a manner which reduces trauma to surrounding tissue. 
     U.S. Pat. No. 4,750,488 and its two continuation Patents, 4,750,901 and 4,922,902 disclose methods and apparatus which utilize a combination of ultrasonic fragmentation, aspiration and cauterization. 
     In an apparatus which fragments tissue by the ultrasonic vibration of a tool tip, it is desirable, for optimum efficiency and energy utilization, that the transducer which provides the ultrasonic vibration should operate at resonant frequency. The transducer design establishes the resonant frequency of the system, while the generator tracks the resonant frequency. The generator produces the electrical driving signal to vibrate the transducer at resonant frequency. However, changes in operational parameters, such as, changes in temperature, thermal expansion and load impedance, result in deviations in the resonant frequency. Accordingly, controlled changes in the frequency of the driving signal are required to track the resonant frequency. This is controlled automatically in the generator. 
     During surgery, fragmentation devices, such as the handpieces described above, are used internally to a patient. A surgeon manipulates the handpiece manually at an operative site, and therefore the handpiece itself may reduce visibility of the operative site. It would therefore be advantageous to provide an apparatus with the above described features with a smaller profile such that a greater field of view is provided for the surgeon at the operative site. 
     SUMMARY 
     An improved ultrasonic surgical apparatus having reduced size includes an ultrasonic handpiece. An ultrasonic fragmenting tool is mounted within the handpiece, the tool having a vibratable tip adapted for ultrasonically fragmenting tissue at a surgical site of a patient. A transducer is mounted within the handpiece and coupled to a connecting body. The connecting body is coupled to the tip for transmitting ultrasonic waves to the tip from the transducer, the tip and the connecting body being constructed of titanium or its alloys. An aspirating system is connected to the handpiece for aspirating fluid and tissue fragmented by the tip from the surgical site. An irrigation system is connected to said handpiece for supplying irrigation fluid to the surgical site for suspending fragmented tissue by the tip. 
     Another improved ultrasonic surgical apparatus having reduced size includes an ultrasonic handpiece. An ultrasonic fragmenting tool is mounted within the handpiece, the tool having a vibratable tip adapted for ultrasonically fragmenting tissue at a surgical site of a patient. A transducer is mounted within the handpiece and coupled to a connecting body. The connecting body is coupled to the tip for transmitting ultrasonic waves to the tip from the transducer, the connecting body is coupled with the tip for transmitting ultrasonic waves at a frequency of at least 35,000 Hz to the tip from the transducer. An aspirating system is connected to the handpiece for aspirating fluid and tissue fragmented by the tip from the surgical site. An irrigation system is connected to said handpiece for supplying irrigation fluid to the surgical site for suspending fragmented tissue by the tip. 
     In alternate embodiments of the ultrasonic surgical apparatus systems described, the transducer may include a stack of magnetostrictive plates longitudinally disposed within the handpiece and responsive to an input frequency for vibrating the tip. The plates can be flat or gusseted and may be fabricated of nickel or alloys thereof. The entire acoustic vibrating assembly (the transducer and its associated components) determines the system frequency. A fluid supply for introducing cooling fluid to the fragmenting tool and/or the transducer may also be provided. The aspiration system may include a detachable aspiration line wherein the aspiration line is removable from the handpiece. The tip may include a cavity formed therein in fluid communication with at least one inlet port positionable at a location adjacent to the surgical site wherein the aspiration system aspirates fluid and tissue fragmented by the tip from the surgical site through the inlet port and the cavity. The handpiece is preferably between about 4.5 and about 6 inches in length, and is preferably cylindrical and between about 0.5 and about 0.7 inches in diameter. The transducer produces standing waves having a wavelength, λ, and the transducer may have a length of about λ/2, the tip have a length of about λ/4 and the connecting body may have a length of about λ/4. 
    
    
     These and other objects, features and advantages of the present disclosure will become apparent from the following detailed description of illustrative embodiments thereof, which is to be read in connection with the accompanying drawings. 
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Various embodiments are described herein with reference to the drawings, wherein: 
     FIG. 1 is a perspective view of an ultrasonic surgical apparatus constructed in accordance with the present disclosure; 
     FIG. 2 is another perspective view of the ultrasonic surgical apparatus of FIG. 1 in accordance with the present disclosure; 
     FIG. 3 is a side cross-sectional view of the surgical apparatus of FIG. 1; 
     FIG. 4 is a top cross-sectional view of the surgical apparatus of FIG. 1; 
     FIG. 5 is a cross-sectional view taken at section line  5 — 5  of FIG. 3 showing a tip and a manifold in operative relationship; 
     FIG. 6 is a cross-sectional view taken at section line  6 — 6  of FIG. 3 showing the tip and the manifold; 
     FIG. 7 is a cross-sectional view taken at section line  7 — 7  of FIG. 3 showing a connector body and an aspiration line; 
     FIG. 8 is a cross-sectional view taken at section line  8 — 8  of FIG. 3 showing the connector body and the aspiration line; 
     FIG. 9 is a cross-sectional view taken at section line  9 — 9  of FIG. 3 showing a stack of plates for an ultrasonic transducer; 
     FIG. 10 is a cross-sectional view taken at section line  10 — 10  of FIG. 3 showing conductors for activating the transducer; 
     FIG. 11 is a cross-sectional view taken at section line  11 — 11  of FIG. 3 showing ports and receptacles for supplying cooling fluid and power, respectively to the apparatus; 
     FIG. 12 is a perspective view with parts separated of a stack assembly; 
     FIG. 13 is a perspective view with parts separated of a transducer coilform assembly; 
     FIG. 14 is a perspective view of a partially assembled transducer coilform assembly; 
     FIG. 15 is a perspective view with parts separated of a handpiece in accordance with the present disclosure; and 
     FIGS. 16 and 17 are perspective views of the surgical apparatus of FIG. 1, mounted in a tip torquing system. 
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     The present disclosure is directed to an apparatus for ultrasonically fragmenting and aspirating tissue in a surgical operation. The apparatus includes a handpiece used by a surgeon to direct fragmentation. The handpiece includes an ultrasonically actuated tip which fragments tissue to be carried away by an aspiration system. An irrigation system which provides cooling fluid to the tip is provided for maintaining temperature within an acceptable range. A cooling system for supplying cooling fluid to the internal active components of the handpiece may also be provided. The handpiece is advantageously reduced in size to permit better maneuverability by a surgeon and to permit a larger field of view during internal surgery through an open incision. 
     Referring now in specific detail to the drawings in which like reference numerals identify similar or identical elements throughout the several views, and initially to FIGS. 1 and 2, one embodiment of an apparatus for ultrasonically fragmenting and aspirating tissue is shown generally as apparatus  10 . Apparatus  10  is embodied in a conveniently held handpiece  12 , a longitudinal cross-sectional view of which is shown in FIG. 3 of the drawings. Handpiece  12  includes a housing  14  which may be a sterilizable plastic or metal, preferably plastic. Housing  14  connects to an irrigation flue  16  at a distal end portion. Flue  16  includes an irrigation port and connection line  18  therein communicating with an opening  20  at a distal end thereof. A tip  22  is shown at a distal end of handpiece  12 . Tip  22  is vibrated to fragment tissue during surgery as will be described in further detail hereinbelow. 
     An aspiration line  24  is shown mounted externally to housing  14 . Aspiration line  24  includes release tabs  26  for dismounting a distal end portion of aspiration line  24 . Further, a tab  28  is included on a proximal end portion of aspiration line  24 . Tabs  26  and  28  secure aspiration line  24  and irrigation line  18  to housing  14  and permit detachment of aspiration line  24  and irrigation line  18  from housing  14 . 
     Handpiece  12  is advantageously significantly reduced in size over known handpieces and provides additional tissue selectivity and better visibility in accordance with the present disclosure. Handpiece  12  is dimensioned at about 4.5 to about 6 in length and about 0.5 to about 0.7 in diameter. This represents at least a 30% reduction in length and width thereby making handpiece more maneuverable and more easily handled by a surgeon during use. 
     Referring to FIGS. 3 and 4, side (FIG. 3) and top (FIG. 4) longitudinal cross-sectional views of handpiece  12  are shown. Housing  14  encloses a resonant vibrator  30  to vibrate in the ultrasonic range, including an aspirating tool vibrating at its tip in the ultrasonic frequency range at a longitudinal amplitude in excess of about 5 mils (0.005 inch). To achieve such an effect in an instrument which can be conveniently held by a surgeon, transmission of excitation to tip  22  is performed at the same time such tip  22  acts as an aspirating inlet to effect the surgical removal of the undesired tissue through cavity  34 . A preaspiration hole or inlet  32  communicates with cavity  34  within tip  22 . During operation, irrigation fluid is supplied through irrigation port  18  into flue  16 . Flue  16  and tip  22  form an annular cavity  36  therebetween. Irrigation fluid is supplied to the distal end of tip  22 , drawn into inlet  32 , and removed by the aspiration system through cavity  34  and aspiration line  24 . Tissue and blood from the surgical site are removed through the distal opening to the cavity  34 . 
     Where highly compliant tissue mixed with blood is aspirated, there is the increased likelihood of occlusion of the aspiration conduit due to the coagulation of the blood. It is therefore desirable to provide as large an aspiration path as possible. In addition, vibration apparently acts to increase the rate of coagulation. It is therefore additionally desirable that the aspiration path or conduit should preferably have minimal changes of direction of flow and where such changes are required, they should be as gentle as possible. 
     Referring now to construction of the resonant vibrator  30 , vibrator  30  functions as a mechanical vibrating system mounted in handpiece  12 . The vibrating system includes a transducer  40  having a magnetostrictive stack  41  preferably composed of a nickel alloy sandwich of flat or gusseted nickel alloy plates responsive to magnetic fields. Electrical oscillating current supplied to a winding of a coil  39  induces mechanical oscillations in transducer  40 , such oscillations preferably being at the resonant frequency and having a maximum practical peak-to-peak stroke (amplitude) of about 0.0002 thousandth of an inch (0.2 mils) at a frequency of about 36 kHz. Due to limitations imposed by the physics of the system, as frequency increases in the ultrasonic range, the stroke that one is able to obtain in the transducer is reduced. 
     However, it is known in the art that if one desires to take the available stroke from the transducer and vary the stroke, an ultrasonic mechanical transformer may be used. The design of such a transformer which is fixedly attached to the transducer magnetostrictive stroke is taught, for instance, in U.S. Pat. No. RE 25,033, incorporated herein by reference. 
     The design of the transformer section must include and yield the preferred characteristics at the output portion of resonant vibrator  30 . In this regard, the output portion of vibrator  30  (the distal end of tool  44 ) may vibrate ultrasonically with a desired stroke (peak to peak) of at least 0.005 to 0.0085 inch (5-8.5 mils). The output portion may also, for surgical requirements, be rather long and slender, while for aspiration purposes it is preferred to have as large a cross-sectional flow area as possible to thereby minimize the possibility of occluding the aspiration conduit. 
     Resonant vibrator  30  further includes a connecting body  42  and a tool  44 . Stack  41 , connecting body  42  and tool  44  function as a three body system. It is therefore advantageous to have lengths of these bodies proportional to the half wavelength of the resonant frequency. The entire system length has a length equal to a multiple of λ/2. An increase in frequency permits a reduction in overall length. (λ=c/frequency). In a preferred embodiment, lengths of stack  41 , connector body  42  and tool  44  are about λ/2,λ/4  and λ/4, respectively. As handpiece  12  is held and manipulated by the surgeon in one of his hands, the size and weight of handpiece  12  is limited by the ability of the hand to delicately grasp and manipulate the instrument. Since handpiece  12  is desirably reduced in size to permit better control by the surgeon and to increase the surgeon&#39;s field of view during surgery, a reduced size apparatus  10  is preferred. A reduction in size of apparatus  10  is difficult to achieve due to physical limitations. Merely downsizing the components of prior art handpieces will result in a design deficient of power (minimal tip displacement) but with high gain (defined as displacement amplitude of a tool over the displacement amplitude of a connector body). 
     Proportionality to resonant wavelength as well as increased frequency due to reduced size are addressed by apparatus  10  by providing a shorter instrument having increased frequency. Advantageously, connecting body  42  and tool  44  are provided having a substantially similar density material which is high in strength. In so doing, power (tip displacement) is increased dramatically for tool  44  at the cost of gain. Surprisingly, gain is still markedly increased in apparatus  10  over the prior art handpieces despite this reduction. Tool  44  includes tip at its distal end portion. Therefore, tip  22  experiences the maximum amplitude of tool  44 . Displacements achieved reached between about 0.005 and about 0.0085 inch. Displacements of this amplitude were achieved for frequencies of about 35 kHz or greater. 
     High strength materials are preferred to handle stress induced in tool  44  and connecting body  42  at the above frequency. Therefore, metals such as titanium and its alloys are preferred. Further, since tool  44  is subjected to high stresses, tool  44  is tapered over most of its length to preferably reduce the stress to which the metal is subjected. Coatings may be applied to tool  44  to improve their characteristics. 
     Tool  44 , in terms of its length and its distributed mass, is a dynamic part of the resonant vibrator  30  which can magnify the 0.0002 inch stroke input induced in the magnetostrictive stack of transducer  40  to in excess of a 0.005 inch output at tip  22 . Connecting body  42  is a unitary structure also dynamically a part of resonant vibrator  30  which serves to connect transducer  40  to tool  44  and, more importantly, to serve to transmit and modify the stroke as it is dynamically transmitted from transducer to tool. 
     A node of motion of resonant vibrator  30  is located in the vicinity of the distal end of connecting body  42  at the interface between the connecting body  42  and the tool  44 . Nodes are locations of high stress and minimal displacement due to the standing waves ultrasonically produced by the transducer. Higher frequencies provide greater tissue selectivity during surgery. Also, power is increased (displacement) by applying increased strain to the materials of tool  44  and connecting body  42 . 
     Power equals force times velocity, and force is proportional to the product of stress and area. Thus, to maximize power of the mechanical resonant structure, the force in the system should be maximized by designing the system components to their endurance strength. The velocity of the resonant structure should also be maximized by maximizing displacement. This can be accomplished by designing as low of a gain vibrator (connecting body  42  and stack  41 ) that still allows for the desired displacement at the distal end of the tool  44 . 
     Handpiece  12  which includes vibrator  30  and connecting body  42  mounted therein may advantageously be reduced in size by using high strength materials having a substantially similar density for both tool  44  and connecting body  42 . A size reduction of about 30% can be achieved in so doing as well as an increased frequency of operation. Such reduction is size permits a surgeon to conveniently hold handpiece  12  in one hand and manipulate it more accurately for improved results during surgery, for example neurosurgery. 
     Connecting body  42  has flange  48  which functions to position the vibrator  30  in handpiece  12 . Flange  48  has O-rings  45  disposed thereabout thereby sealing and separating off a distal end portion of housing  14  for cooling fluid circulation. O-ring  52  engages connecting body  42  and seals irrigation fluid in flue  16 . Tool  44  and stack  41  threadably engage connector body  42  as shown in FIG.  3 . 
     During operation of handpiece  12 , heat is generated. To remove this heat, a transducer housing (coilform)  54  houses stack  41  and includes ports  56  at a proximal end portion for accessing stack with a cooling fluid to lower temperatures therein. Housing  54  further includes access ports  56  for supplying power to circuitry of transducer  40 . 
     FIGS. 5 and 6 are transverse cross-sectional views of tool  44  taken through section lines  5 — 5  and  6 — 6  in FIG. 3, respectively. Tool  44  is substantially circular and disposed within flue  16  (FIG.  5 ). Flue  16  supplies irrigation fluid to an operative site during surgery (FIG.  6 ). Since flue  16  is a hollow member, ridges  57  are included for strength and may contact tool  44 . Ridges  57  help to maintain flue  16  and tool  44  concentric. 
     FIG. 7 is a transverse cross-sectional view through connector body  42  taken at section lines  7 — 7  indicated in FIG.  3 . Aspiration line  24  communicates with cavity  34  of tool  44  by passing through connector body  42 . A space  60  is defined between connector body  42  and a cap  62  which engages flue  16  (FIG. 3) to permit vibrations of the system without contact between cap  62  and connector body  42 . Also, irrigation port  18  is shown. 
     Referring to FIG. 8, a transverse cross-sectional view of connector body  42  is shown section lines  8 — 8  indicated in FIG.  3 . Connecting body  42  is shown spaced apart from transducer housing  54  to permit vibrations therebetween. Aspiration line  24  is shown having a coupling  64  for releasing aspiration line  24  when tabs  26  are depressed. 
     FIG. 9, a cross-sectional view taken along section line  9 — 9  in FIG. 3, illustrates stack  41  having a plurality of magnetostrictive plates  68 . Stack  41  is disposed within transducer housing  54  which is disposed within a tube  70 . Conductors  72  are disposed in grooves  74  formed in transducer housing  54 . A conductive sheet  71  surrounds conductors  72 . Coil  39  is wrapped about transducer housing  54  for extending a magnetic field created by coil  39 . Housing  14  is also shown. 
     Referring to FIG. 10, a proximal end of stack  41  is shown as well as proximal ends of conductors  72 . Engagement pins  76  are shown in cross-section and engage conductors  72  to make an electrical connection thereto. Transducer housing  54  has flanges  77  extending therefrom with openings  78  formed in each flange to receive conductors  72 . A recess  80  formed in housing  14  receives a clip  82  for securing aspiration line  24  to housing  14 . Tab  28  on clip  82  is used to secure the flue tube  18  on the handpiece housing  14 . Clip  82  may be detached from housing  14  by unclipping. 
     As is shown in FIG. 11, engagement pins  76  are dimensioned and configured to receive plugs (not shown) of an electrical connector to supply power to stack  41  through conductors  72  and coil  39  (FIG.  3 ). Two ports  84  are provided for providing access to cavity adjacent to stack  41 . Cooling fluid may be introduced and removed as a heat transfer medium to reduce temperatures of stack  41  during operation. An antirotation block  86  is included to prevent rotation of end cap  73  within housing  14 . Aspiration line  24  includes a larger diameter tube thereon to provide easier maintenance of suction at the operative site. 
     A stack assembly  43  is shown in exploded detail in FIG.  12 . Stack  41  is assembled by stacking and connecting plates  68  and applying a sleeve  90  and an end cap  92  thereto. A threaded end cap  94  connects to a distal end portion of stack  41 . End cap  94  threadedly engages connector body  42 . The elements of stack assembly  43  may be brazed together to prevent separation. 
     Referring to FIGS. 13 and 14, an exploded and assembled view of a transducer housing assembly  88  is shown. Transducer housing (coilform)  54  includes grooves  74  and flanges  77  with openings  78  for receiving conductors  72  therein. Conductive sheet  71  is placed around coilform  54 . Engagement pins  76  are inserted into holes  98  formed in a proximal end portion of transducer housing (coilform)  54 . Pins  76  engage conductors  72  which provide electrical current to and thereby activate coil  39 . Sheet  71  is preferably a high conductivity metal, such as copper. Sheet  71  includes an extended portion  98  for connection to engagement pins  76 . Current is supplied by engagement pins  76  to conductors  72  passed through coil  39  and returned through other conductors  72  and engagement pins  76 . In this way current is directed through the coil  39  to create a magnetic flux. 
     Transducer housing (coilform)  54  is inserted within tube  70  and engages a flange  101  at a proximal end portion of housing  54 . Housing  54  is maintained and sealed within tube  70  by  0 -rings  100 . A fastener  102  further secures transducer housing  54  in tube  70  at its distal end portion by snapping into a groove  103  on the distal end portion of housing  54 . FIG. 14 shows transducer housing  54  partially assembled to show the placement of sheet  71  and conductors  72 . Extended portion  98  engages return pin  99  while the remaining pins  76  engage conductors  72 . 
     FIG. 15 shows assembly of handpiece  12  by threading tool  44  into stack assembly  43  to form the three masses for vibrator  30  (FIG.  3 ). Transducer housing assembly  88  is inserted in housing  14  and stack assembly  43  and transducer housing assembly  88  are attached to housing  14 . The interface between tool  44  and connecting body  42  is positioned near a node. Stack assembly  43  is slid into transducer housing assembly  88  inside housing  14 . At the connection area between stack assembly  43  and housing assembly  88 , O-ring seals  102  are used and secured by a clip  104  within an opening in the distal end portion of housing  14 . Cap  62  is coupled to housing  14  by a bayonet type coupling  106 . An O-ring  101  seals a distal end portion of the connector body  42  to cap  62 . A proximal end portion of cap  62  is sealed off with O-ring  109 . Flue  16  is attached to cap  62 . 
     Guide plates  110  communicate with ports  56  (FIG. 3) and engagement pin  76  locations (FIG. 3) to permit engagement by a plug (not shown) to supply cooling fluid and power to transducer assembly  88 . End cap  73  and a plug  112  fit into distal end portion of housing  14 . An O-ring  114  provides a seal between end cap  73  and housing  14 . 
     Aspiration line  24  is connecting to connecting body  42  in communication with tip  22 . Coupling  64  detachably connects aspiration line  24  to cap  62 . Clip  28  fits into groove  80  of housing  14  for securing aspiration line  24  thereto by connecting to a stepped tube  116 . A larger diameter tube  115  also connects to stepped tube  116 . 
     Referring to FIGS. 16 and 17, apparatus  10  is mounted in a fixture  130  for supporting apparatus  10 . Fixture  130  includes bracket  132  for supporting handpiece  12  at or near node on connecting body  42 . A handle  136  is provided for stabilizing supporting fixture  130  and apparatus  10 . Supporting fixtures facilitates the attachment and/or removal of tools  44 . 
     It will be understood that various modifications may be made to the embodiments disclosed herein. For example, compensation for tissue fragmentation may be provided to maintain the standing wave in apparatus  10 . Further, the compensation may be provided by a compensation circuit which supplies additional current when tip  22  is in contact with tissue to maintain the standing wave. Also, guidance systems may be used to assist a surgeon during surgery, particularly neurosurgery. Therefore, the above description should not be construed as limiting, but merely as exemplifications of preferred embodiments. Those skilled in the art will envision other modifications within the scope and spirit of the claims appended hereto.

Technology Classification (CPC): 0