the difficulty in permitting axial movement of the ultrasonic transducer can be removed by replacing the piezo - electric transducer of the prior art with one using a hollow magnetostrictive transducer which requires no direct electrical connection and can safely withstand immersion in aqueous irrigating solutions . kleesattel first disclosed a removable solenoid magnetostrictive transducer ( u . s . pat . no . 3 , 076 , 904 ). his design , elegant in its simplicity and function , was incorporated first into ultrasonic dental handpieces for the removal of plaque from teeth and then into banko and kelman &# 39 ; s apparatus ( u . s . pat . no . 3 , 589 , 363 ), which formed the basis for the now universally practiced medical procedure of phaco - emulsification . it was also used in wuchinich &# 39 ; s ultrasonic surgical aspirator ( u . s . pat . no . 4 , 063 , 557 ; u . s . pat . no . 4 , 223 , 676 ; u . s . pat . no . 4 , 425 , 115 ), which found widespread acceptance in neurosurgery for the removal of brain tumors . however , these designs used a solid slender bar composed of layered thin magnetostrictive sheet material , such as permanickle . broadwin and rose ( u . s . pat . no . 4 , 986 , 808 ) later disclosed a magnetostrictive transducer having a central axial hole . such an opening is desirable to permit passage of a telescope and to provide an aspiration pathway , but their design , using fins of magnetostrictive material radially positioned about the tubular hole , was intended for open site surgical procedures where retraction of the cutting tip is not required and it does not fully utilize the limited space available for transducer material in a resectoscope . as shown in fig1 , which is a cross sectional view of the instrument , a hollow magnetostrictive transducer 9 is attached 22 to a hollow ultrasonic horn 15 , which is attached 20 to a slender tip 17 having an open end for contacting , cutting and aspirating tissue . the attachments 22 and 20 may be made by any of the methods known to the art such as welding , brazing , screw threading , press - fitting or using adhesives . the horn 15 can also be removably attached 20 to a tip . such attachments using screw threads are well known in the art . both the transducer 9 , attached horn 15 and tip 17 slide together within a sleeve 29 made of non - electrically conductive material . a telescope 2 and aspiration tube 21 run from one end of the sleeve 29 through the transducer and the horn 15 . the aspiration tube is press fit or otherwise attached 36 to the opening in the tip 17 while a slot 37 in the horn accommodates passage of the telescope . the telescope then overlies the tip with its objective 12 located near the open end of the tip terminus 38 . power to vibrate the transducer 9 is provided by an electric coil 8 positioned about the outside of the sleeve 29 , which is made of non electrically conductive material . as the energy is transferred to the transducer by the magnetic field produced by the coil , and not by direct electrical contact , as is the case with piezo - electric transducers , this transducer is free to move axially within limits and yet receive power to vibrate . thus the transducer / horn combination can be extended and retracted at will . axial motion is provided by supporting the transducer and horn within the sleeve 29 only at points of little or no ultrasonic motion , known as nodes . this method of support is described by wuchinich in u . s . pat . no . 5 , 176 , 677 and u . s . pat . no . 4 , 750 , 902 for use in ultrasonic surgical instruments and is well known in the art and hereby incorporated herein by reference . the coil spring supports 23 for the transducer and 16 for the horn permit axial movement of the transducer - horn - tip combination while not impeding the flow of irrigation fluid over the tip or about the transducer . this form of support , as described in u . s . pat . no . 3 , 323 , 785 , consists of a coil spring joined to itself to form a toroidal spring stretched over the transducer or horn to elastically support the structures while allowing fluids to pass over the transducer and horn . to provide an electro - cautery current to the tip , a connection 6 is provided for a source of electro - cauterizing current and connected to a sliding electrical contact 7 with the transducer 9 . certain magnetostrictive materials , such as permanickel ( a trademark for a high nickel alloy ), are electrically conductive and will convey such currents . the horn 15 and tip 17 can also be made of electrically conductive material , such as 6a1 - 4v titanium , so that this current can be made available at the tissue - excising open end of the horn . the telescope 2 , releasably fitted and retained within the sleeve 29 utilizing any of the several methods common in the design of endoscopes , is typically of the conventional relay lens type having a typical shaft diameter of 4 millimeters and integral fiber - optic illumination cable . irrigating fluid , supplied from a container positioned above the patient , is admitted through a valve 10 to the inside of the sleeve by conventional lure - lock 11 connection . when the valve is opened the fluid flows through the sleeve and into the surgical site under gravity . the telescope 2 and aspiration tube 21 are equipped with irrigation fluid seals 25 and the seal provided the aspiration tube also permits axial movement of the tube . use of o - rings to provide such sealing and movement is well known in the art . the transducer / horn assembly is moved axially using the aspiration tube 21 to which it is attached 37 . this tube is mechanically fixed 39 to the spring 27 loaded moveable component of an iglesias thumb 39 and finger 4 , 26 mechanism . squeezing the thumb and finger grip together advances the transducer / horn assembly , while releasing the grips alls the spring 27 to retract the assembly . the aspiration tube , terminating at 1 in the vicinity of the grip , is attached to a source of vacuum , commonly available in surgical operating rooms . such simple attachments are well known in the art . this source may also be valved to initiate and terminate applied vacuum upon surgical demand . the sleeve 29 , which encloses the vibration source , horn and tip assembly , is surrounded by a removable metal sheath 14 . this sheath is similar to that used with resectoscopes , attaching to the body of the instrument using a releasable spring catch . it is admitted into the prostatic gland or bladder using an obturator . this device is inserted into the sheath at the commencement of surgery . it contains a moveable tip that can be angled to negotiate the 90 - degree bend in the urethra as it approaches the prostate . once the sheath is in place within the anatomy , the obturator is removed and the instrument , containing all the elements of the invention , is inserted and locked in the sheath at coupling 13 using well - established fixtures intended for this purpose in endoscopy . the use of such devices is well known in endoscopy and in the practice of endo - urology . of particular interest in endosurgery is the circumference of the sheath , as the natural body orifice through which the instrument is introduced must often be dilated to accommodate the sheath . the smaller in circumference the sheath can be made , the less trauma is inflicted upon the tissues forming the orifice during insertion . fig1 shows the invention is in its essential form with all functional components delineated for clarity . it is obvious to practitioners skilled in the art and viewing fig1 that the circumference of sheath 14 can be reduced by changing its diameter just to the right of the joint 20 where the tip 17 is attached to the horn 15 . so done , the sheath then need only enclose the telescope and the tip in that portion of its length that is inserted into the natural orifice , and thereby reduce the needed dilation of the orifice . indeed , it is also obvious that the coupling 13 between the sheath 14 and the sleeve 29 can be moved just to right of joint 20 where the tip 17 attaches to the horn , thereby permitting use of a uniformly sized sheath of reduced size to produce less dilation . none of these modifications alter in any way the operation or function of the instrument . magnetostrictive transducers are known to generate significant heat in converting electrical energy into mechanical vibration and normally require cooling . this heat results both from the mechanical stress of vibration and from eddy currents if the magnetostrictive material is a metal . in the dental prophylactic scaling ultrasonic tool using kleesattel &# 39 ; s solenoid transducer design , cooling was provided by passing the tap water irrigation used for lavage first around the transducer . in wuchinich &# 39 ; s ultrasonic surgical aspirator a separate water circulating cooling supply was provided the transducer . in this invention cooling is provided by the irrigation fluid , which is admitted to entire inner region of the sleeve , both that enclosing the horn 15 and tip 17 and that surrounding the transducer 9 . normally this fluid flows out through the open end of the sleeve into the surgical field . to pass a small portion of this flow in the other direction and about the transducer 9 , an opening 5 , much smaller than the inner diameter of the irrigation tube , is made as shown . as this tube is normally connected to a source of vacuum , some irrigation fluid is drawn through this opening to create a flow to cool the transducer . because the aspiration opening 5 in the irrigation tube is much smaller than the open , tissue - excising , end of the tip the vacuum available for tissue dissection is not significantly diminished . wuchinich in u . s . pat . no . 4 , 493 , 694 discloses this method of redirecting a portion of the irrigating flow in a surgical instrument . to fully utilize the space available for magnetostrictive material , and thus maximize the amount of vibrational power that can be provided in the restricted space of a resectoscope , the transducer is constructed of spirally rolled magnetostrictive sheet or of tubular ferro - ceramic ( ferrite ) material . fig2 illustrates the construction if the magnetostrictive material is a metal , such as permanickel . a thin sheet of the material is required to minimize the heating produced by eddy currents generated in the metal by the magnetic field . the rolled sheet is contained within two hollow end caps 34 , which are attached 32 to the ends of the roll 30 using any of the methods available for making mechanical bonds , such as welding , brazing , soldering and adhesives . these caps , which prevent the spiral roll from unwinding , can be eliminated by just welding , brazing or other otherwise joining the edges of the roll . once contained within the cap closures , the spiral roll 30 is slit axially 33 from its outer to inner surfaces . this slit interrupts circumferential poisson coupled motion in the roll that always accompanies axial motion and ensures that the transducer produces principally axial motion , whose direction 35 is shown , when energized by the surrounding magnetic field . the sliding contact for conducting electro - cautery current to the ultrasonic horn contacts the outer surface of the spirally rolled transducer 30 . if a permanickel sheet is utilized to form the transducer an oxide is normally present on its surface . this oxide layer insulates the adjacent surfaces of the roll and prevents the production of eddy currents from circulating through its entire radial thickness . to establish electrical contact for application of the electro - cauterizing current , a strip of this oxide is removed from the outer roll surface . one face 31 of one of the end caps is mechanically attached to the ultrasonic horn , again using any one of the forms of electrically conductive mechanical attachment , including adhesives , solder , welds , braze , press - fit , screw thread and self - locking luer that are known to those skilled in the practice of the art . this invention discloses a preferred method of generating axially directed mechanical vibration for the purpose of removing tissue in surgical operations that permits independent movement of the ultrasonic components with respect to other elements of the invention , and as such it embraces all forms of providing such motion , including the use of resonantly vibrating component parts of the ultrasonic assembly . for example , the transducer can be designed to resonantly vibrate in the axial direction at a particular frequency and the ultrasonic horn can also be designed to vibrate in the same manner and at the same frequency . methods for producing such designs are well known in the art . furthermore , the horn can be composed of several horns , all joined integrally or releasably coupled together to provide increased length or an increase in vibration in the region of tissue contact . the invention also includes other forms of ultrasonic motion that can be generated by magnetostrictive transducers and conveyed by ultrasonic horns , such as torsional , longitudinal - torsional and flexural motions . although electro - coagulating current is preferred for use in the surgical procedures using this invention , to those skilled in the art it is obvious that electro - cutting current can as well be applied to the horn without altering any elements described and disclosed . it is also well known in the art that the invention also permits the use of laser coagulation by the incorporation within or about the telescope of a fiber optic channel to convey such coagulating illumination such as provided by the co 2 , ktp , pvp or holmium lasers to the operative site .
a surgical instrument comprising a sleeve , a electro - mechanical transducer containing a hollow passage for producing mechanical vibrations in response to a magnetic field , an ultrasonic horn mechanically connected to the transducer , containing a hollow passage communicating with that in the transducer , for amplifying the produced vibration such that dissection of biological tissue is produced and a tip having a hollow passage , mechanically connected to the horn and whose passage communicates with that in the horn , for contacting such tissue , connection of the passage to a source of vacuum and a sheath connected to the instrument and surrounding the tip and horn , with a connection to a source of irrigating fluid and a structure for mounting the transducer and horn within the sleeve permitting retracting and extension of the transducer and horn within and with respect to the sheath . the transducer , horn and tip are immersed in the irrigating solution . the instrument may also include a telescope for viewing the tissue contacting site and provision for electrifying the tip with electro - cauterizing current as well as provision for the use of endo - laser fulguration of the site .