CA1303448C

CA1303448C - Ultrasonic device for applying cavitation forces

Info

Publication number: CA1303448C
Application number: CA000607261A
Authority: CA
Inventors: Howard M. Alliger; Donald J. Ciervo
Original assignee: Sonic Needle Corp
Current assignee: Sonic Needle Corp
Priority date: 1988-08-05
Filing date: 1989-08-02
Publication date: 1992-06-16
Anticipated expiration: 2009-08-02
Also published as: US4920954A; WO1990001300A1; AU4079689A

Abstract

ABSTRACT OF THE DISCLOSURE
An ultrasonic device for applying cavitation forces to an unwanted material is provided. The device is particularly useful for removing plaque from a human artery wherein a portion of the device can enter all artery and pass through the artery to the vicinity of the plaque. The device includes a solid wire of titanium material, a trandsducer, a generator for providing vibration energy via the transducer, and a handpiece enclosing the transducer and having a tapered end portion with an exponential surface of slightly concave profile. The tapered end portion is fixedly connected to an inner end of the wire. For human applications, the wire has an overall length in the range of about from 5 inches to 40 inches and has a uniform outer diameter in the range of about from 0.015 inches to 0.040 inches. The device includes a catheter assembly having a catheter tube enclosing the wire and includes a container unit mounted on the tapered end portion of the handpiece. The container unit has a fluid chamber for receiving a contrast material, which passes through the chamber, through the catheter tube, to the outer and tip portions of the wire and tube in the area of the plaque to be removed. The container unit also has a coupling funit forming an outer end wall thereof having a fixed portion and a rotatable knob portion for moving the catheter tube axially relative to the wire for adjusting the extension of the outer end tip portion of the wire beyond the outer end tip portion of the catheter tube.

Description

~L3~3~4~3 ULTRASONIC DEVICE FOR APPLYING CAVITATION ~ORCES

~KGROUN OF I~D~IN~TI~l The inventio~ generally relates to a~ ultraso~ic device, and in particular the inventio~ relates to an ultrasonic cavition de~rice ha~ing a ~vire which is composed of a metal haYillg a relatively low modulus of elasticity suchas ~ita~ium. The ~lre has a length and a diame~er dimensioned f~r specific applications of remo~ral of unwanted maleriaL One application, for e~ample, is ~h~ r~moval of plaqua from a human arterg by th~ action of 1uid caYitation.
Another application, for e~ample, is the remo~al of ~ontaminants ~rom o~herwise iDaccessible areas of industrial par~s, such as aerospace parts.
Rela~d U. S. Patsnt Numbers i~clude:
3,352,303, i~uedNoYcmber1~ 67, IS 3,565,062, issued F0bruary 23, 1971, 3,S89,363, ~u~d Jurle 29, 1971 3,618,594, issued November 9, 1571, 3,861,391, issued J~nuary21, 197~, ~,474,180, issued Oetober 2, 1984, a~
4,660,573, issued April 28, 1987.
R~la~d publications i~clude:
I ) "A Critical Appraisal o~ M~thods for Disruptio~ and E~traction of Uri~ary Calculi Especially with Ultrasound", by Harold Lamport asld Herbert F~
Newma~, The Yal~ Journal of Biology and Medicine, Yolume 27, Number 5, JUQe, 1955. ~

L3~13 2) "A Ne~ Me~hcd to Cure Thrombi by Ultr~sonic C~vila~ioll", by U.
Stumpff, R. Pohlman alld G. Trub stein~ Ultrasonics International 197S
Conference Proceedings.

3) '`Prelimi~ary Feasibility Studies Using a~ UltrasonicDe~rice îor 5 Endarterectomy", by Harry L. Finkelstei~. M. D., et al, The Mount Sinai Jour~al Or Medicine. Volume 46, Number 2, M3rch-April, 1979.

4~ Tech~ical Support Pac~age En~itled "Sp~sulation on Ultraso~ic Dlsin~gra~ion of Ar~erial Deposits". Geor~e C. Marshall Space Fli~ht Cetlter, Ma~hall Space Fligh~ Cent~r, Alabama 3S812. ~inter 1983, Volume 8, Numb~r 2.
MFS-25161.
The prior ar~ devices which ha~e ende~vored to ren~o~e un~anted material from the huma~ body or o~her inacces3ible are~s have severe limit~ions. In most of ~hese devices the sonic wa~e guide or aclive probeis shora and rigid. In tho cæe of ureter stones. the activc tube or wir~ is about IS 4S cm lon~ " ), bu~ is still fairly rigid. The urhary duct is straightened by the metal wire ins~rlion. This ca~no~ be the case. however. if on~ is ~o reach the coronary arteries percutaneously by ~tering a blood ~essel al the neclc or armpit. Similarly, it is ~ot possible to thread rigid wire down ~he leg ~hen theastg~ or vein to be cleaned is sinuous. In these inst~nces, the ultraso~ic 20 waveguide or ~ire rlust be long, narrow ~d highly fle~ible i~l osder to pass ~hrough the vessel without causing damage. Further, becaus~ ~here is a sta~di~g soundw~vo i~ the ~ire, th~ metal Gomposi~ion must provide minimum ~enua~ion of t&e sonic energy. In layma~'s terms, ~he metal must be capable of ringing like a bell. Esperime~ats ha~e skow~ that this property is especially25 i~nportans wheh the wire is bent, since bending greatly increases the tendency for e~ergy ln ~he sou~d waYs to be dissipated as he~ a~d a si~r~ifican~
temperature rise would not be tolerable.
The procass of trans~tting sound ~avas illtO arteries of the heart or leg by inserting a wire through the blood vesæls ~as first ~ried in the5 early lg60's~ A~ that time sta~ndard ultrasonic illstrumellts beca~me a~railable for laboratory homoeenizi~g and emulsifying. These devices were portable ultrasonic probes. about 1i2" dia~meter, and had abou~ ~OO times the iDtensity or vibrasion ampli~de of the more common ultrasonic ~ak cleaQers. A long wire could be auached ~o the vibra~ing end of these probes, and the ~rire then la maneuvered through the blood ves~ls. Energizing the proba would in turn activate the wire. Al~hough reachin~ occlusions in tl~e leg by wire was sometimes succ0ssful. the process of plaque ramoval ~ras not. Energy transmitted to the vibfatin~ tip was insufficien~ to produce t~e rlecessary cavi~ion (bubble collapse) for disrup~i~g or llquefyhg plaque. Removal of IS simple blood clots or th~mbi i~ the 1~, a far less demandiQg applica~ion, wasalso unsucc~ssful. For this a~d oth~r raasons, th~ d~Yicc disclo~d jn U. S. Pa~n~
No. 3,3~2.303, 1~7, "Method For Blood Clot Lysis" had si~ni~ica~t limi~ions. Arterial plaque could be remo~r~d by ultrasound as discussed in publicatioll number 3 cited above, but the procedure was p~rformed wi~h a 20 rela~ely shorc rigid probe a~d i~ was necessa~ to completely ope~ the arte~ and e~pose the occlusiYe plaqù~.
The idea of threading a~ ultraso~ic wire i~to blood vessels ~æ
beeQ tried ma~y times in the last 25 yea~s, and ~ith good reason.
Arteriosclerosis is the number one ~iller i~ the ~vester~ ~orld. U~fortuately. a2~ vibra~iQg pereutaneous wire system ne~er showed promi~ iQ treatmeQt of this ~3l~)3~8 .~

disease, nor did it provide data suitable for reporting in t.he scientiNc literature.
When power was i~creased to ~he wire, it overheated, and moreover. tended to vibrate itself apart. Well before reasonable displacement was achieved at Lhe tip, ~e wire bro~e, usually at the at~chment point to the horn.
In publication 4 cited above, ~he authors su~gest tha~ remoYing arterial deposits Sy ul~rasonic disinlegralion would be a~ e~cellen~ idea. After a number of in~res~igations, they concluded ~hat t,his area of ul~rasound was apparently ~irtually une~plored.
U. S~ Patent No. 4,~l7~1,180, 1984, A~aratus_~r Disin~e8rata~g KidneY Stones, attempts lo lncrease the useful life of wire in kidney stone breaking by utilizing a long damper ~ube. This tube closely fits arou~d tlhe wire ~ea~ its aluachmen~ to the horn. a~d reduces u~desir~ble ~ransve~e vibra~ion.
However, a close fil~hg tube placed ~ny~rhere along the ~r~e ~rould li~i~ both lo~gi~udinal as well as lateral motion, a~d thereÇore the tip displaceme~t wouldbe much reduced. A separate ca~heter referred to in the same pate~t, is specifically mad6 loose to avoid such a difficulty. In U. S, Pate~t No. 3,861,391, 1975, AD~a~ratus for D~ te~raSion o~rinarY ~" no mention is made, or suggestio~s offered, ~s to the type of m~tal to be used in this pate~ o~ the previously eited p~tent. 1~ was ~o~ importa~t to t~e inve~tlDr. The same is ~he 2n case for U. S. Pa~e~ No. ~,66~,573, 1987, Ultrasonic Lithotript~ Probe, B0cause o~ its ~reat strength and hi~h proportional limit, stai~less st~el asld other high streng~h steels wes e used as wire or wa~reguides in past blood clot disruption e~periments. These metals are n~ow i~ standard use askidney s~o~e brea~ers, In U. S. Pa~e~t No, 3,56S,062, 1971, Ultrasonic Method and ADpal~atus for Remo~i~g Cholesterol and Other ~eposits rom Blood Vessels ~3~4~3 and the kike, the inve~tor goes into detail as to how and why his device worb;s.l:Ie suggests ~he use of Monel a~d stainless steel as ~raveguides. Similarly in U. S.
Patent No . 3,618,~9~. 1971, Ultraso~is Appara~us fo~ Reti~al Reastachm~
the inven~orsuggests ~he use o Monel for the acti~re probe. Similasly S in U. S. Patent No. 3,352,303, cited above, the invantor sugges~s s~ainless steel or Monel. Also i~ U. S. Pa~ent No. 3,589.363, the vibr~ion transmittihg matsrial is suggested to be Monel metal with only the operaei~e tipcomprising "a~ e~tremely hard. s ;erilizable ma~erial, such as titanium".
One problem with c~rtain prior art ul~rasonic delrice is ~has the wire, ~vhich is rela~ively short and relaSiYely rigid, is not suitable for eQtering i~to a~ ar~sy in ~he armpit or ~ec~ area of ~e human body, a~d for passi~g through ~he artery to the ViCiQity of the heart.
In one ultraso~ic kidney stone device, U. S. Pat~t No. 3,861,391.
cited ~bove, ~he wire is specifically designed to hcreas~ whipping motion a~ theIS tip so ss ~o break ~he s~ones faster. Kidney stones ho~ever, for tho most par~ are no~ brck~n by caYita~ion, or ~he maki~g a~cl brea~ing of bubbl~s, but by poundi~g or a j~cl~hammer ~f~ec~.
In U. S. Paten~ No. 3,565,~6Z, cited abo~e, ~he iD~0~r ~ecognizes that he~t genera~ion is a problem during blood clot remo~al and indicates ~t discr~te pomts on ~e wire wa~eguide will glow red ho~. The inve~tor "solYes"
the problem by constantly changin,~ the frequency so that nodes and anti-nodes o~ the wire physically shift, as well. But unfortuna~ely, the wire. for the most part, will only resonate at ~he fundamental frequency for which it was designed, a~d çhangillg freque~cies is tantamount to turning the apparatus on 2S a~d off.

In publicalion 2 cited ~bove, the wthoss discuss dissolving thrombi utilizing an ultrasonic wa~guide but apparently if no liquid is supplied via the waveguide, the temperalure becomes so high tha~ the ~rall of the vessel can be bur~ed.
Another problem encountered in the percutaneous removalof plaque, or o~er applica~ions Or ehis Icind, is the auachmeni of the wire to the horn. Sinse the horn ~nd ~ire cnnnot be fabrica~ed as one continuous piece, energy losses ~ill occur ~t t~is junction. A similar proble~ arises with devicesfor ~idney stone brealting. Harmonic genera~ion and reflections occur a~ ~he a~achment site, and these a~nua~ the funda~nensal wave a~d cau~e po~rer loss.
~hen the ~ecessary a~ount of power is ~inally delivered to the wire tip, ~he a~c~ment poi~ will usuaLly hea~ up a~d break ir~ a few seconds unless cooli~g water is applied. This is the case wi~h both ~id~ey sto~e brealcirfg ~d cataractremoval, butwould be eve~ more noticeable in the plaque re~oval process ~here a small diameter and longer w~ is ~lece~y and the amplitudes requir~d are higher.
Methods o~ aUachil~g ul~rasonlc wire and ~ubes i~ ~he past include: bsa~ing, welding, threadi~g, epo~ g, a~d cla~pi~g. These were fou~d iDadequate ill pr~ t plaqu~ and blood clot applica~io~ beca~e. e~cept ror threading, each causes too f~uch power loss or hoating. Perhaps 90 7. o~ theapplied energy is wasted i~ kidney stone brea~i~g, alth~ugh th0 high strength me~l used as tra~smittingwir~ or lubes ca~ withs~nd the e~tra stress aud hea~. Furthermore. i~ is no~ dif~lcult to cool ~bLe vibra~i~g ~vire wi~h running water, or sali~e, as a kidney sto~e is behlg so~ica~ed.
2S Bra~ing or solderi~g ma~es a poor bo~d wi~h titanium. Bra~i~e, ~L3~344~

too, tends to anneal stainless steel so that some of the sound wave is damped or re.flected. Weldlng temperatures required for titanium change the grain ~tructure at the heated junation, producing non-linearity as well as weakening the metal. Both epoxy bonding, and attachment hy clamping or thumb screw, result in too much loss and heat. Producing a screw thread on titanlum wire 1 mm in diameter is not possible at present.
In U.S. Patent No. 4,474,180, cited above, an impxoved method of attaching wire to a vibrating ultrasonic horn is described. The wire "life" is prolonged to a little over a minute, rather than the previous time to breakage of 20 seconds.
This performance is clearly not acceptable in our projected blood vessel applications where much longer times will likely be needed to destroy arterial plaque. Noreover~ just the threat of wire breaking during insertion into the hear~ arteries ls unacceptable.
SUMMARY OF THE INVENTION
In accordance with the present invention there is provided an ultrasoni~ devlce for use ln removing an unwanted material from an artery of a human body by cavitation comprising:
a wlre having a fixst end portion and having a second end portion for causing cavitation adjacent to the unwanted material; support means having a handpiece having a tapered horn end portion with a~
integral metal joint fixedly connected to the first end portion of the wire; drive means including a transducer supported by the handpiece for providing ultrasonic vibration through ~he tapered horn end portion to khe wire and for connection to a generatox;
and a catheter as~embly surrounding said wire and moveable relative to the wire to permit the second end portion of the wire ..~

r3~

~303~

7a 72690-8 to be positioned adjacent to ~he unwan~ed material; wherein said catheter assembly has a catheter tube and a container unlt, ~aid contalner uni~ including a peripheral wall and a front end wall portion and a rear end wall portion enclosing a cavity, said catheter ~ube having a Pirst end portion connected ~o the container unit and having a second end portion disposed around the second end portion of the wire; and wherein ~aid peripheral wall o~ said container unit has an annular interior partition projecting into said cavity, said par~ition havin~ an 0-ring member through which the wire passes, said 0-riny member and partition formlng a front sealed chamber and a separate rear chamber in said cavity; and wherein said O~ring member and partition are located at a selective dlstance ~rom the tapered horn end portion, said location of the 0-ring member being at a nodal point o~ a longitudinal wave o~ vibration o~ the wire, thereby minlmizlng transverse move~ent of the wire at the 0-ring member and avolding relatively high stress due to a transverse wave at ~he in~egral metal ~oint~
In accordance with the present invention there is ~urther provided an ultrasonic device for use in removing an unwanted material in a normally inaccessible area by cavitation comprising a relatively long, flexible wire having a first end portion and having a second end portion ior causing cavitation adjacent to the un~anted material; support means having a handpiece wi~h a tapered horn end por~ion having an integral me~al joint fixedly connected to the first end portion of the wire;
drive means including transducer means supported by the handpiece ~31~4~3 7b 72690 8 for providing ultrasonic vibration throuyh the tapered horn end portion of the wire and for connection to a qenerator, catheter assembly means surroundinq sald wire and having portions moveable relative to the wire to permit the second end portion o~ the wire to be positioned adjacent to the unwanted material; and transverse motion damping means disposed within the catheter assembly ~eans and surrounding ~he wire for minimizing transverse motion of the wlre and avoiding rela~ively high stress at khe integral metal joint due to a transverse wave.
We have developed an ultrasonic system which will remove arterial plaque and blood clots and be useful in treatlng other diseases as well. It was ~ound that althouqh a long wire seemed to break easily when sonic power was applled, wire strength, per se, was not the necessary or overriding ~actor. A~ it turned out the modulus of elasticity and the actua:L wire diameter are the key elements. Other findinqs and improvements also aided in this difficult ultrasonic applic~tion.
Collagenous tissues such as bone, cartilaqe, and, in this case blood vessels, are not easily affected by ultrasonic action or cavitation. Therefore ~31~339~4l3 ultrasound transmiued through a wire, if sufficient, can seleGtively disrupt embedded plaque and ~lood clots while leaving the blood vessels intact. During Iysis, the space be~ween ~vire and its catheter sleeve can be used to evacualte debris, if necessary.
According to the present invention, an ultrasonic cavitatior.
device is provided, ~rhich uses c~vitation or microscopic bubble ac~ion to removs plaque fro!n an artery, and which ca~ eQter a~ artery in the armpitorneck areaandQassthrough the artery to ehe vici~ity ofthehea~rt.
The prese~t i~vehtion is suitable for elimi~ion of plaque or any other form of occlusion in blood vessels or bodily organs as well as unwa~nted materi~l in i~accessible areas of other items such as industrial palrts. Such ultraso~ic cavit~tion device includes a solid wîre, ~vhich is composed of a ~netallic material ha~inB ~he characteristics of sitanium metal an,d ~vhich has a~;vire o~erall leng~handhasa~ireou~rdiame~er sui~abl~ for the particula~r applica~ion.
Such de~ric~ a~lso has a ha~dpiece which hals a tapered end portion tha~ is fixedly co~nected to the wire ~r supporting the wire, a tra~nsducer disposed withill the ha~dpiece for vibratillg the ~rire, a~d a generator for energi~ing e transducsr.
By usir,~g the solid wire as descrlbed immedia~ely above, the ultrasonic device accnrding to the invention overcomes the problem of providing a wire suitable for e~teriQg into, for e~mple, a~ artery leadi~g to theocclusion arldforpassing ~hroughtheartesy to theimmediate vici~ityof the occlusion.
The results of our rece~t. e~periments, revealed that the ~34~

stress/strain char~c~eristics of tita~ium alloys were far better for this applica~ion than ~hose of hiBh strength stainless steel or other metal alloys like Monel, Inconel, or piano wire (350,000 psi). Tita~ium is sometimes used as horn or ~ip material on ultrasonic devices because it is chemicallyinert, andits 5 ha~rdness resists cavitation erosion. Tit~ium is also relatively non lossy to sound waves~ These are not the particular physical properties, however.
~hatmake ~ta~ium indespensible as the wire mehl in plaque removal or even difficult kidney stone applications, a~d unSil ~ow tita~iu~n has not been used as a wa~reguide i~ these fields.
Titanium has a moderately hig~ proportional limis but combi~es this characteristic ~ h a low modulus of elasticity. ~e found that titanium alloys with the lowest modulus Or ~lasticity ~d not the highest ssrellgth, worked best. This ~inding israther surprising consideri~g thc emphasisin publication 1, cited above, that a metal ~i~h a high Youllg's modulus would be lS beuer suited to this applica~ion.
At high stress, t~e stress~strain characteristics of tit~nium metal remaia l~ear, but more importa~ltly, provlde reL~ively greac movemen~
(S~aiQ) or displacement, Qluminum has a~ even lower modulus than titanium, which would appear to ma~e i~ more useful iQ this applicatioll. But this metal 20 ~lso ~as a very low proportional Jimit and, there~ore, will bre~k at rela~ive~y low s~ress before lt can attai~ a reasonable tip Yibra~ion or displaceme~t. If one is to aehie~e a pa~ticular strain, or tip movemen~, a lower modulus ( indicated by a more hor~ontal slope ill Fig. 3 ) would permi~ a lo~ver proportional limit. The reverse is no~ so simple in practic~, ho~ever, A higher proportional limit ~5 would allo~r a higher modulus, in theory. But the applied stress or e~ergy in ~303d~

this case is i~ereased to a point which cwæs unwan~ed harmo~ics to appear. As a result. the vrire be~ns to shake a~d vibra~e laterally since it does ~ot transform all the i~reas~d stress into useful longitudinal motioll. Tempera~ur0 rises and caus~s both the fatigue strength and the proportional limitto g~
5 duwn~ Sound transmission characterls~ics may also change. In ~he case of higher proportional limit and higher modulus. there is a greater tendency the~
for ~he wire t~ break, ~o lose power ~ a bend, and to hea~ ~he at~achmen~ point.ConYersely, a lower mndulus has a co~npounding adqantageous eff~ct by aYoiding ul~wanted vibra~ion, due to high stress, and the resulting heal 10 generation. Reducislg losses and heat is particularly important if the sonic w~re is placed in an ar~e~y whero it cannot be easily coolsd by "runni~g water". A
lower modulus pro~rides yet another desirable metal proper~y. The wire can be strained more easily and is less stiff or ~nergy absorbing on bei~g bentor threaded t~rough ~he arteri~ stcm.
lS The property of lower modulus alone, however, was still not enoueh to produce a complet~ly workable ultrasonis syst~m wher~ flesibili~y and ba~din~ was n~cessary. It ~ras found also that a particular wir~ diama~er was required depe~diQg UpOD~ the specific applica~ion. Diameters much larger or smaller th2n jus~ u~der 1 mm wers not useful i~l mos~ blood Yessel 20 applications, for example. At diameters much above 1 mmL, the wire, ~rh~n ben~
~ppeared too s~iff, becam~ energy absorbing, and a graa~ deal of sound energy wasted. Whe~ wire diametar becomss too small. a trans~rersa degr~a of freedom appears allo~i~g th8 wire to vibrale laterally like a plusked string;
This motioll tends to stress t~e wire particularly a~ its poiJl~ of a~tachmen~ to the 25 horn.

13i[~39L48 ln order to achieve high a~ial displacement amplitudes, the method of attachment of the ~ire to the hsrn mus~ be smoo~h a~d symme~rieal so as Meither to absorb nor to reflsct energy, and to minimize tra~sverse waves.Two noYel qvays of wire al~chment ~ere found ~o be successful as will be S e~plalned All unwanted vibraiions or harmonics ~re desrimental because they cause reflec~ioQs a~d generate both hea~ and lateral motion in the wire.
These harmonics awLd transverse (side-to-side) mo~iot~s are not produced, or arenot ~ppare~t, Lll sta~dard labora~ry ultrasonic horns a~d probes, but appear as 10 the probe becomes ~hintler and more wire-like. In th~s present plaque applic~ion as well as in ~idney stone brealcing, ~h~ elestronic genera~or alld the horn feed~ng the ~ire both contribute to this ~oll-linearit~r ~y producing or trans~it~ing o~her ~ha~ a perfectly cle~ ~unda~nell~al waY0. The standasd st~p horn which gives the greates~ amplitude to labora~of~r sonic probes was l5 not the bes~ choice for transmitti~g ~he genera~ed energy into the smaller diameter wire. The conical horn ~as also ~o~ ideal. It was found tha~ a horn ~ith a non-lineas taper, sometimes called an ~ponential horn, worked best for this purpos~. The e~pollential horn ei~her did no~produce unwa~ted frequencies aRd harmonics, ~r a~tenu~ed them sufficiently such tha~
20 less were tra~smitted to the at~ached wire. ~Yhen using a~ expos~eD~tial horn to tra~smit sound ener~y, the wire could be operated a~ove ilS preYiously ma~ium rated a~plitude before breaking.
As mentioned, the attachment point of the ~vire t~ ~he horn is critical because the energy transmitted to the wire and load passesthru this 25 junction, a point which is physically non linear. The desired axi~l standing 131:)3~8 wave produces an antinode here which fortunately is a point of minimum stress. However, all transverse wa~es in the wire produce a node, or point of ma~imum stressa~theattachm~nt. Any tra~nsverse flesing must therefore be stopped or damped since at high power levels i~ will cause the wire to break.
This ~as a~ccomplished by att~ching a rigid tube or sleeve 1~ nodal points on either side of ehe wire/horn attachment, Shus greatly reducillg a~y stress on the wire here.
The foregoing a~d other objects, featu~es a~nd ad~aQtages will be apparen~ from the following description of ~he preferred embodimen~ of the inven~ion as illustraSad in the accompanying drawiQgs~

~,~Q~

Figure I is a perspective vie~r of an ultræonic device being used to remove plaque in a hum~n being according to the invention;
~igur~ 2 is an enlar~ed sectioD. vie~ of the ~ira aUashmeD.
portion of ~igure l;
Figure 3 is a graph o~ stress versus strai~ cus~res of stainless seeel, titaQium a~nd aluminum;
Figure 4 is a~ enlarged perspecti~ra vie~r of the ul~rasoniG
device of Figure 1:
~igure 5 is an enlarged section view of ~ portion of ~igure 4;
Figure 6 is a dis~ssembled perspective view gene;all~ of Figure d 2S ~igures 7 a, b and c are perspective vlews showing YarioUS t~rpes of so~ic horns which tra~smit a~d amplify the ultrasonir wa~re.

.31~34~L~

DESCRIETION ~ XHE P~ M~O~

As illustrated in Figure 1 a human being 8 is being treated by an ultrasonic device 10 of ~he presentinve~tionviaanincisionllinthearmpit 5 area and thence through a coro~ary artery 12 to a plaque deposit 13 thsreiQ.
Artery 12 e~tends to the heart 14~
The ultrasonic devlce 10 has a wire 16 which acts as a ~aveguide that is positionably disposed within a c~heter a~sembly 17. The wire 16 is maneuvered via the incision 11 through the artes y 12 to be proximale the area 10 of plaque 13 for remvval thereof in a m~ner to be e~plained~
Referring now to Figures 1, 2. 4 a~d 5, device 10 also has a handpiece 18, ~hat contains a piezoelectric or magnetostrictive convert~r or traQsducer 19 therein ~hich produces ultraso~ic energy a~d transmits it to the wire 16, and a generator 22 ~hich ellergiz0s the transducer 19. ~andpi0ce 18 15 has an expoQential horn or tapered portion 20, ~hich has a surface21~ hasan e3ponential concave profile. Handpiece 18also has an elongate drilled hole 2~ that receives an il~ner end of ~irs 16. A solder join~
material 25 is present in the region behreen ah inner surface of hole 2~ and an outer surface of wire 16 adjacent there~. The thic~ness of Ihe solder material 20 25 shown in ~igure 2 is exagg0rated for oase of illustration.
In the ~irst novel process of attac~ing tb e wire 16 to the horn 20, the mati~g surfaces of hole 24 and wire 16 are firs~ coatsd with a bra~able material such as nickel or copper by a pla~ing procsss such as electroplating or electrolssspla~ing. With bo~h mating sur~aces now coated, th~ wire 16 2~ can be braeed or soldered by coD.vesl~ional means. resulting in a strorg continuous ~ond to the horn 20. Thus, the wire 16 and tapered portion 20 are i3034A8 joined, so as to pre~rent any rela~ive distortion or deflection thesebetween, and so as to form a co~Ltinuous, non-interrupted metal material for ease of transmission of ~ibra~ion. The joint a~ solder material 25 is long eQollgh to withstand the Yibration energy applied t~erea~ and does not cause any substantial reflection of the waves of vibra~ion passi~g therethrough.
A second alter~ative novel method of attachme~t of the wire 16 to the horn 20 i~ by a friction fit or shri~k fit. IQ ~he process of manufacture, a hole 24 slightly smaller tha~ the diameter of ~he wire 16 is first drilled into the end 73 of ~he horn 20. Tl~e end 7~ of t~e horn 20 is heated ~nd~he wire 16 ~s Gooled. Wit~ the wire 16 held securely, for e~ample in acollet ( not sho~n), ~he horn 20 is slo~ly fotced or tspped onto the wire 16. W~en both wire 16 and hor~ 20 return to the a~bienl leJaperature, Ihe wire 16 e~pands and the metal around the hole 24 co~ts to form a bcnd s~rnng enough to ~i~hsta~d the high energy of vibration.
Wire 16 is composed of litanium metal. The characteristics of ~Ahe ~ire 16 i~cluding the le~gth and diamet~s depelld upon the specific applicatio~. ~or use in the human body, f~r esample, the overall 10ngth of the wire 1$ is in the ra~ge o~ about S inches (12.7 ceQ~iJneters) so 40 i~ches ~101.6ce~timeters) while tho range of effec~ive wire diameters isabout.015 inches ( 0.381 n~illimeters) to 0.040 inches ~1.016 ~illimetes~s). At diameters much below this range, the wire ~ends So break at high intensities since the sou~d wa~ra is more easily div~rted to ~hat seemed to be transverse or ~hippi~g motion. rather than lhe lo~gitudinal motio~ ~vhich produces cavitatioll . At diameters much above 1 mm. the wire, ~vhen bent ~ppeas ed too s~iff, became sound absorbing, and a great d0al Or sou~d en~rgywasted. 11l order to reach and ent0r the coronary arteries, as opposed to leg arteries, a diameter as small as possible or close to 0.020 inches (1~ mm) is advisable.
The sound losses in a bent wire are Losses = K (D~R), 5 where D is the diameter of the wire, R is the radius of the bend and K a co~stant.
The larger the diameter of the wire or smaller the be~d radius, the more ~he sound wa~e difîers in ~he time i~ takes to move from one point t~ anoth~r through the length of the wire. The path leQgth along the inside bend radius is shurt~r t~an that along the outside and this distorts the wave ~ront.
10 FurtherJnore, the stress on the metal also varies between the inAer alld outer circumference; the i~er bei~g under compressio~ and the ou~er under tension. This difference iQ stress alters the density and therefore the speed ofsou~d i3~ the wire. All the above changes produce na~ earity of transmission and result i~ heatiQg, harmonics, a~d lateral motion.
15 Accordingly, the diameter has to be kept as small as possible in order to mi~imi~e these losses.
T~i~ner ~rire, below 1 mm in diameter, although producing îewer losses due to a lower D~R ra~io. beeomes .highly susceptible to transYers0wa~es t~at D.aturall~ appea~, even ~ hout bendiQg or ~igh amplitudesa~ld 20 the ~ire will vibrate laterally. This motio~ ds to s~ress ths ~ire particularly ai its point of a~tachment to ~he horn.
The freque~cy is importa~ iQ th~ the stresses and heat dissipation increase in the wire as the sound frequerlc~r is raised. This is due to ~he grea~er acceleration of the wire molecules. Belowabou~20 Kh~ however, 25 hi~h pitched noise may become objec~ionable. ~or a give~ power level, the lower the ~requency, the higher the cavitatio~ inteQsity.

~303441! 3 ln Figure 3, a conve~tio~al graph of stress versus strain is shown. The graph has a~ upper curve 26 for stainlesssteel~vhich hasa proportional limit poin~ 32 aDd a failure point 33. The graph also h~s a lower cur~e 30 for aluminum which has a proportional limit point 3~ a~d a failure S point35. The graph also hæ a middle curYe 28 Çor tita~ium which hasa proportlo~al limi~ point 36 a~d ~ failure point 37. By observatio~ and compar~son of ~he three cur~res 26. 28. 30, it is concluded tha~ for a gi~lre~
rela~ively high s~ress level, t~e middle curve 2~ ~or titanium mat~rial proYidesthe larges~ rela~ive s~rain. Thus, for a given leng~h of wiro 16 composed of a titanium m~erial, a ma~imum displacement of wire 16 a~ its outer tip portlon would occur, ~h~roby providillg a ma~um amoun~ of cavitation or fluid bubble action for removing plaqua 13 from astery 12.
In Figure 3, the modulus of elastici~y, which is the ratio of the str~ss to the s~ , is iQdica~ted by ~he respective slopes of curves Z6, 28, 30. ~y lS compari~g tha slopes of cusves 26, 28, 30, the cur~,re 28 for ~ iux material is agaul found to be more suitable, than curv~ 26 of stai~less steel material or cur~e30Ofaluminum ~ rial, îor th~ ~pplic~io~ discussad ~erei~ sinco it yields a lar~r stra~ or tip ~o~reme~t for a s~all~r appli~d s~ress or ultsasonic inteQSi~,y.
In Figurc 3, v~rtical li~l8 29 passing through tha proportional limi~ poin~ 36 of cur~o 28 of ti;~iu~ material shows th~ maxhnum strain possible in ~rire 16 of tit~ium ~erial. For a s01ected len~h of ~ire in this embodim~n~, th~ change i~ length oî wire 16~ corrasponding to ~ho StraiQ
al line 29, is about 0.008 inches p~r i~ch.
In Figuro ~. an anlarged Yi~W of g~n~rator 22 is shown.

~L3~
17~

Generator 2~ has an o~-off sqritch 38, a pow~r set~ing contsol knob 40 and a power meter 42. G~nerator 22 also has a power line 44 for inærtio~ in a conventional 110 voll outlet, and a connecting line 46 ~hich e~tendsfrom generator 22 to handpiece 18.
1~ operation, an operator, such as a surgeon, mo~itors the power meter 42 asd applies low power at ~nob 40, during the surgical maneuvering of the outer ~ip end portion of ~ire 16 toward the plaqu~ 13 to be remoYed in artef y 12. UPOQ contact of the outer tip e~d portion of wire 1~ wi~h the plaque13, which is indica~d by an increase iQ the ~eading of meter ~2, ~he operator applies high po~ver a~ knob 40 for g0llerating cavitation adjacen~ to the plaqueor occlusion 13 for removing the plaque or occlusinn. Altern~tively, ~he opera~tor ca~ monitor ~he ~nover~en~ of the outer ~ip e~d portion of wire 16 toward the plaque to be remov0d in ~rt~ry 12 by x-~ay techniques, for example, by using a c~ntrast medium in a manner to be e~plained.
In Figure 5. ca~heter assembly 17 ineludes a catheter tube 48, a container unit S0. a Cl)UpliQ~ UQi~ S4. and a &o.nt~st fit~ 100~ The ca~heter tube 48 may be ~eflo~ or may have a~ inner surfase o~ tefloh or other inert material having a low coef~iiien~ of ~icsion to slip easilq over the wire 16.
~ tain0r 50 includes a peripher~l wall or sleeve 52 al~dacouplingunitS4.
Coupling uni~ 5~, ~vhich is somewha~ similar ~o a couplhg unit for a garden hose, has æ fi~ed portio~L S6 ~hich is fi2edly connected to sleeve 52,and has a rotatable portion or knob por~ion 58 vrhich is rotatable relalive to ~ise portion S6. in order to asially displace gliding sleeve 59 rela~ive to fi~ed portion 56. Knob 58 is a~ached to portlon 56 ~o permit rotation but no a~ial movement 2S therebetween. A~lal movement is i~parted to sleeve 59 by rotation of knob 58.

al3~8 Catheter tube 48 is connscted to co~rast fitting 100 which is connected to portion S~ a~d moves relative to knob S8, for a~ial displacemelllof tub0 48 relative to sleeve S2~ In this way, by rotating k~ob 58, tube 48 is a~ially displaceable relative to wire 16, so th~ the outer tip portion of wire 16 can beS slightly exte~ded, when causiQg cavita~ion, beyond the outer tip por~io~ of tube ~, which is normally flush for passing through artery 12.
Rotatable portio~ 58 has a seal mea~s (not shown) i~ order to preventlea~agefromcoupling54. Fised portio~ 56is fi~edly conn0ctedtothe adjace&~ portio~ of sleeve 52 and has asealmeaQsinlheformof0-ring66to preveht leai~age from coupling 54.
Co~tras~ fitti~g 100 has a hole 60, whi~h receiYes a syring0 62 a~
its tip por~ion. for depositine an ~-ray contrast ~luid or medium from syringe 62 throug~ hole60 into a front cha~ber 68. Sleeve 52 has a~ ner annular projec~ion 6~, ~hich supports the ~r~g nllem~ber 66~ One purpose of the O-r~flg ~ember 66 is ~o seal chamber 68, ~Ivhich co~lains ~he contras~luid. ~ri~B
membsr 66 s~parates îront chamber 68 from ~ chamber 70.
In Figure 5, ~ring member 66 h~ inner hole ~hrough which wire 16 passes. ~rin8 member 66 sealinely engages ~ire 16. The size of such hole ir~ ~rin~ member 66 is e~aggerated hl Figure 5 Çor ease of illus~io~.
~ring member66 is located at anodalpointof wire 16 which is locatedaca seleeted dime~sion 72 ~way from th8 tip end face or attachmentpoi~730 tapered portion 20, as explai~ed hereafter.
Cohtai~er u~i~ Sû also has a sealed conneclion 76 for co~nec~ioQ
~;~ of co~tainer unit 50 to tapered portion 20. Co~ec~ion 76 ma~ includ~ an 0-ring member~o~ sleeve S2 which bears a8ains~ a part of surface 21 of tapered ~31~3~

,9 portion 20. Connection 76 is a~ a nodal point of tapered portion 20which is located a~ a sele~d dimension 74 away from the tip end face 73 of tapered por~ion 20, as explained hereafter.
0-ring membee 66, which is ~ a~ al~ial nodal poin~ of ~ire 16. is 5 able ~o d~npen ~he tr~sverse force on wire 16 at that poiQ~ when ~vire 16 ls vibr~ted by ~he horrl 20. 0-ring member 66 does not substantially dampe~ the longitNdinal vibration waves in wire 16. Thus. severe bendirlg ~I~d relatively high stresses, at the regio~ of ~ira 16 adjacen~ ~he a~tachment point ~o ~he end face 73 of t~e tapered portion 20, is avoided.
The nodal point i~ ~rirc 16 at ~ring member 66 applies to bo~h the transv~rse ~ re and lo~gitudi~al wave of vibra~loQ in wir~ 16. The nodal poin~ has substantially no mov~ment. An allti~ode point be~een ~wo ~odal points has ~ ~imum movemen~. The point o~ wire 16 a~ ~h8 end face of tapered portioQ 20, or the ~rire aUachm~nt poi~, acts as ~n a~tinode poin~ for IS the longitudinal~ve of vibration, and acts as a nodal poinLfor~he u~wanted transverse wave of vibration.
The opera~on o~ de~ice 10 is e~plained hereafter. FL~st, ~he pereutaneous entsy to ~he ~rtery 12 is made in a conventional ma~ner via incision 11. Then, ~ube {~ and wire l6 are passed through arter~ 12 of body 8 to20 the ~ricinity of the plaque 13. The operator, such as the surgeon, adjus~s the ge~erator 22 fol lo~v power Oll control ~nob 40, and watches the reading on meter 42, while passing the tube 48 a~d ~ire 16 toward the heart 14, When the plaque to be removed is contacted slightly, the reading on meter ~2 eha~ges.
The sur~eo~ ~he~ pro~rides high power o~ control knob ~0, there~y causing 25 ca~itation of fluid adjacen~ to the plaque. Tbe surgeon may move the tip of wise ~93~4~3 -~o-16 sligh~ly toward ~he plaque 13 ~s the tissue is liquefied or disper~ed.
Unless there is a tolal occlusion. Ihe blood flow pasl the plaque 13 earries lhe minute par icles of displaced plaque a~way. In ~he case of a lolal occlusion ~he particles can be aspirated ~rou~h ~he ca~heterassembly 17.
5 Based upon in ~itro e~periments, it is e~pected ~hat Ihe sonica~d particles removed from the plaque 13 will be belo~ IS microns ~nd be absorbed or eliminated without 8re~ difficulty by t.he body.
A COQtl'aSI medium is deposited in the fluid in front chambe~ 68 from syri~ge 62. The conlrastmedium passes ~hrough the ca~he~er ~8 lo ~he tip IC of wire 16 at Ihe sile of ~he plaque 13. Convenlional ~-ray equipmenL, or theli~e. ca~ form a picture of $he ~ip of ~ire 16, tAhe ~ip of ~ube ~8, and the adjacenl diseas~d portion of artsry 12 The surgeo~ ca~ make judgmgnts on how to ~o~e the tip of wire 16, and ~here to position the tip of tube ~ d ths lilce, duri~g the remo~ral of the plaque 13.
In ~he case Or removal of a blood clot or o~ber large occlusion, whe~ there is lit~le or no b~ood llow, the same procedure ls followed wi~ some e~cep~io~s. It may be desirable i~o remoYe the particl0s of ~he occlusio~ co~tinuously. The ~yri~ge 52 can be remo~red from hole 60 a~t a con~rentional pump aUached therelo, in order to a~pirate the disperscd par~icles20 of ~h~ occlusio~ rom the site thereof t~rough tube S8~ ~o fron~ chamber 68, and out through ~e pu~qp. Tube 48 has a passage therethrQugh, of circular cross sectio~, for~ned belween the outer surrace o~ wire 16 and fhe inner surrace of tube 48.
For purposes of ~urther e~pla~ation, Fi~ure 6 provides a 2S disassembled perspective view generally of that portioll of ul~rasonic device 10 ~3~

shown ir~ Figure 5. Parts of device lOa, vrhich correspond lo similar parts of device 10, have the same numerals. but with a subscript "a" added thereto.
Device 10a includes a wire 16a. and ~ catheter assembly 17a.
Device lOa has an e~ponential horn or ~apered portion 20a, ~hich has a surface 21a. Wire 15a is fi~edly connected to tapered por~ion 20a by a solder join~ 25a.Wire 16a is composed of a titanium material. Wire 16a is a waveguide for longitudiQal vibr~ion ~vaves from horn portion 20a. The longitudinal vib~ ion waves cause an a~ial movemen~ of the ~ip portion of wire 16a, th~r~by callsing cavita~ion, ~vhich removes pla~ue 13a from açt~ry 12a.
~heter assembly 17a includes a ca~heter tube 48a, and a container or d~mpel~ing unit 50a. Uni~ 50a has a sleeve or peripheral wall 52a and a coupli~g unit 5~a. Unit 5~a is used to a~ially displalc~ ~ire 16a relative to ca~hetel ~ub~ 48a, iQ order to e~t~nd a~ ~d portio~ of ~ir~ 16a, for ~or~ing on plaque 13ainartery12a. Coupli~gullit ~la has afi~ed portion 56a,whieh is fi~edly co~nected ~o sleeve 52a, a~d h~s a rotatable portio~ 58a, which is a~gu~ly movable rel~ive to fised por~ion 561a. for a~ially displaeing ca~eter ~ube 48a.
DeYice 10~ also has a fitli~g lOOa. which is fi~edly eonnected a~
on0 e~d ~hereof lo a tubular member 59a th~ co~necls to rotahble portion 58a, alld which is fi~edly co~nected ~ the other e~d ~hereof to ca~he~er tube 48a.
FiUing 100a has a hole 60a, for receiving a syringe ( Qot show~. A con~rast madium may be added by the syri~e to fluid il~ a~ eloQgate pa~sagew~y of a~nular cross-sectio~, ~hich is Çormed be~wee~ an outer sur~ace of wir~ 16a and an inner surface of catheter ~ube ~8a, in order to hav~ a con~rast m0dium in ~he fluid loca~d ne~t to plaque 13a.

~3~3~

-2~-D~vice lOa also has an 0-ring 66a. which ~s positioned at a select~d d~st~nc~ from the end fac~ 73a of hor~ portion 20a. 0 ri~g 66a is locat~d at a nodal point of the longitudinal vibration wav~ ~rhich defin~s a nodal point of the tr~s~erse vibratio~ wa~e, in order to minhniz~ wire stresses a~ th~ end face5 73a of horn portion 20a. and in ord0r to preveni transverse movement or whipping of wire 16a at ~he location of th~ 0-ring 66a.
Sleeve or dampeni~g uni~ SOa l~as a co~nec~ioD.~to tapered hor~ por~ion 20a for as~mbly thereof.
~ heter tub~ ~18a is compose d of a suitable plas~ic material, such as tefloQ. Fitting 100a is composed of a st:linless steel ~terial. Sl~eve 52a iscomposed of a suitable plas~i~ material. Wire 16a is composed of a tita~ium material. El~ponential horn 20a is ~omposed of a titanium m~rial. Coupling 5~a is composed of a stahlless steel or other sui~able ma~erial.
~ igures 7a, b and c show various configura~io~s of horns. In 1~ ~igure 7a, a standard s~ep horn 110 is show.~ which pro~ides the greates~
amplitude for labora~ory sonic probes bu~ is QO~ the bes~ choic~ Çor transmitli~g energy into wire o~ the diameter used ln the presen~ ~pplication.
In ~igure 7b, a conical shaped horn 111 is showQ which ls also less than ideaL
Ill Fi~ure 7c, ~he esponential horn 112 h~vi~g ~ taper e~~wa~bes~orthe 20 presen~ applica~io~ since unwa~ted frequencies a~d harmo~ics were ~ini~ized and the ~ ium wire d~scribed pro~riously could be operaled abo~e it previousl7 ma~imum sated amplitude beÇore breaking.
There a~re a number of ad~rantages to deYic~ 10 as indica~ed hereafter:
~5 1. Device lû h~ a fle~ible solid wire 16 which has dime~sions alld parameters suit~ble îor en~ering body 8 and then passing through the body ~ to the asterial occlusio~.
2. Wire 16 maintains a s~ding wave, transfers vibra~ioQ
e~er~y, and provides a cavitation or bubbleactiona~thesi~ofocclusionfor 5 disintegra~ion of the obstruction 3. FiUi~g unit 100 provides a means to pass a contræL
medium ~hrough artery 12 to the tip of ~rir~ 16-through tube ~8 for obtaining an x-ray or flouroscopic picture ~hile moving wire 16 asld tube 48.
~ . Wire 16 is a fle~ble solid wire composed of ~i~ium 10 metæl, whereby rela~ive ma~imum displaceme~ oî the tip of wire 16 is obtai~ed resulting in relative masimum cavi~ion. This is due to the unique characteristics of ~he modulus of elastici~y and the stress level possible.
5. Titanium ~ire 16 has bend portions with pronouncod curvatures, saused by ent~y bends aQd ar~ry be~ds, bu~ ~rire 16 avoids 15 corresponding portions of high stress and hea~i~g for longer life.
6. Device 10 has tra~s~er~æ ~ve nodal points a~0-ring member 66, a~d a~ end face 73 of ~apered portio~ ~0, whereby stress a~ the end face 73 is minimi~ed for lo~ger life.
7. Espos~en~ial surface 21 of e~ponential tapered portio~
20 20 mi~hnizes u~aflted frequencies in ~e vibration waves passing to wire 16, thereby a~rolding heating of ~ire 16 especially at end facs 73 alld aYoiding a whippillg of wire 16 ther~by ~i~imi~i~g wir~ fatigu~ ~d wir~ breakage.
There are a number of o~her advantages to device 10. Device 10 is believed to be useful in treatiflg other diseases, as well as plague or blood c~ots.
25 as ~ollows:

~3~3~4~3 1. remo~ calcium from heart valves, 2. dispersing clumps of streptococcus bacter~ on heart Yal~res, 3. arrhythmia control by sonica~ion of asrhy~hmia f~ci 5 i~ ~he heal~ muscle, 4. clearil~g bila ducts, . remo~ g tonsils 6. breaki~gallst3~s, 7. sh~ri~ kid~ey s~nes atld urs~r stones, a~d 8. treating prost~ic hypertrophy or prostate cancer.
Further, for e~ample, deYice 10 can be uæd ~ sonicat~ or eo provide a ~mporary hole i~ the hear~ ~all or septum be~ezn the h~
auricles o~ a newborn infant, ~vhere there is insufficie~Lt o~yge~ated blood a~
birth. Thi~ operation aLlo~s temporary bypass of o~ygen~ted blood in the sigh~
IS auricle to pass to the left auricle. This temporary ultrasonic operation is perrormed prior to a con~e~io~al operation for th0 transposition of th~ main arteries of the n~wborn infant a~d results if~ inimal damage to the hcart co~p~ed with the curre~t techniques. ThLs opsra~io~ ls performed using d~rice lO with the help oî ultrasound scanning to prcvide ~naging at the same 2û time.
Although, ~ inYen~ion has be~ describ~d primarily with respect to the removal oî plaque iQ arteries of hum~n beings, it will be appreciated tha~ un--~ted contamillants can be remo~ed ~rom i~accessible areas i& indus~rial, commercial and eve~ household applical;ions by ~he use of 2S an ultrasonic ca~rita~ion device lO.

~3~)3~8 For e3ample, device 10 could be utili~ed OQ a production li~e for removal of unwa~ed production co~t3minants from inaccessible areas Or fin~shed or semi-finished products.
As another e~ample, devic~ 10 c~ be used as an industrial S instrument, for removing unwanted material. such as the removal of cal~ed gre~se in a minu~ passageway of a small compone~t inside of an a~rospace product of an aircraft, ~ereby avoiding the need for disassembb of the co~po~n~ and product.
While t~e i~ell~ion has been described i~ its pref0rred 10 embodiment, it is ~o be unders~ood that ~he words whieh ha~re been used are words of descrip~ion rather ~ha~ limita~ion and th~ changes m.qy be made ~ithi~ ~he purview o~ the appended claims wi~houl depar~i~g from the true scope and spirit of the i~ver~ion i~ its broader aspects~

Claims

1. An ultrasonic device for use in removing an unwanted material from an artery of a human body by cavitation comprising:
a wire having a first end portion and having a second end portion for causing cavitation adjacent to the unwanted material;
support means having a handpiece having a tapered horn end portion with an integral metal joint fixedly connected to the first end portion of the wire;
drive means including a transducer supported by the handpiece for providing ultrasonic vibration through the tapered horn end portion to the wire and for connection to a generator; and a catheter assembly surrounding said wire and moveable relative to the wire to permit the second end portion of the wire to be positioned adjacent to the unwanted material; wherein said catheter assembly has a catheter tube and a container unit, said container unit including a peripheral wall and a front end wall portion and a rear end wall portion enclosing a cavity, said catheter tube having a first end portion connected to the container unit and having a second end portion disposed around the second end portion of the wire; and wherein said peripheral wall of said container unit has an annular interior partition projecting into said cavity, said partition having an O-ring member through which the wire passes, said O-ring member and partition forming a front sealed chamber and a separate rear chamber in said cavity; and wherein said O-ring member and partition are located at a selective distance from the tapered horn end portion, said location of the O-ring member being at a nodal point of a longitudinal wave of vibration of the wire, thereby minimizing transverse movement of the wire at the O-ring member and avoiding relatively high stress due to a transverse wave at the integral metal joint.

2. The device of claim 1, wherein said wire has an overall length in the range of about 5 inched to 40 inches, and said wire has a uniform diameter in the range of about 0.015 inches to 0.040 inches, and said wire has a length to diameter ratio of a value about up to 2700.

3. The device of claim 1, wherein said wire is composed of a titanium alloy having a low modulus of elasticity.

4. The device of claim 1, wherein said tapered horn end portion has an exponential shaped outer surface.

5. The device of claim 1, wherein said front end wall of said container unit forms a coupling unit, said coupling unit having a fixed portion fixedly connected to said peripheral wall, said coupling having a rotatable portion movable along a longitudinal axis relative to the fixed portion when rotated, said rotatable portion being connected to the first end portion of said catheter tube, whereby the second end portion of said catheter tube can be moved relative to the second end portion of the wire, for extending the wire beyond the catheter tube during cavitation action.

6. The device of claim 5, wherein said rear end wall of said container unit has a fixed connection to the tapered portion of the support means.

7. The device of claim 1, wherein said container unit has a passage means extending from the exterior thereof to the front chamber, for passing an x-ray contrast medium into the fluid in the front chamber, and for passing of the contrast medium from the chamber through the catheter tube to the vicinity of the second end portion of the wire.

8. The device of claim 1, wherein said container unit has a passage means extending from the exterior thereof to the front chamber for aspirating material through said catheter tube.

9. The device of claim 1, wherein said integral metal joint is formed by the mating surfaces being initially coated with a brazable material by a plating process and then brazed or soldered together.

10. The device of claim 1, wherein said integral metal joint is formed by a shrink fit between said wire and said tapered end portion.

11. An ultrasonic device for use in removing an unwanted material in a normally inaccessible area by cavitation comprising a relatively long, flexible wire having a first end portion and having a second end portion for causing cavitation adjacent to the unwanted material;
support means having a handpiece with a tapered horn end portion having an integral metal joint fixedly connected to the first end portion of the wire;
drive means including transducer means supported by the handpiece for providing ultrasonic vibration through the tapered horn end portion of the wire and for connection to a generator, catheter assembly means surrounding said wire and having portions moveable relative to the wire to permit the second end portion of the wire to be positioned adjacent to the unwanted material; and transverse motion damping means disposed within the catheter assembly means and surrounding the wire for minimizing transverse motion of the wire and avoiding relatively high stress at the integral metal joint due to a transverse wave.

12. The device of claim 11, wherein said wire is composed of a titanium alloy having a low modulus of elasticity.

13. The device of claim 12, wherein said wire has an overall length in the range of about 5 to 40 inches and a uniform diameter in the range of about 0.015 to 0.040 inches.

14. The device of claim 11, wherein said tapered horn end portion has an exponential shaped outer surface.