Material Removal Apparatus And Method Employing High Frequency Vibrations

Abstract

An instrument for breaking apart and removal of unwanted material, especially suitable for surgical operations such cataract removal, including a handheld instrument having an operative tip vibrating at a frequency in the ultrasonic range with an amplitude controllable up to several thousandths of an inch. The operative tip is itself hollow and is in turn surrounded by a tubular sleeve to form an annular passage. The handpiece includes transducer means for converting a high frequency alternating current into mechanical vibrations and an impedance transformer for coupling these vibrations to the operative tips. Connections are also provided on the handpiece to a source of treatment fluid and a pump. The treatment fluid may be coupled to either the hollow interior of the tool or the surrounding annular passage, while the pump is coupled to the other. During use, the vibration of the operative tip against the tissue to be removed causes the latter to break apart into small particles which are then dispersed in the fluid flowing over the operative region. Concurrently, the pump withdraws the suspension of the tissue particles in the fluid from the operative site. The fluid flow must be regulated so as to control the pressure within limits at the operative site. The instrument is thus suitable for removing tissue from an enclosed area whereby the opening to permit access to the tissue to be removed need only be large enough to admit the tip of the operative tool.

Description

The present invention relates to material removal devices and methods, and more particularly to an instrument having a working operative tip vibrating at high frequencies and with minute amplitudes for breaking apart and removing material from relatively inaccessible places and techniques for its use. Although by no means limited thereto, the present apparatus is of particular advantage when employed as a surgical instrument for breaking apart and the removal of unwanted tissue.

Vibratory assemblies for the cutting of material have been in use for some time in a wide number of applications. One form of such apparatus employs a slurry formed of particles of abrasive material in a liquid medium in conjunction with an ultrasonically vibrating tool, whereby the vibratory energy imparted to the abrasive particles in the slurry hurl them against the surface to be cut with tremendous accelerations, thereby literally chipping away the material. This technique has been applied with great success to a wide variety of uses, particularly with respect to industrial machine tools.

However, this type of ultrasonic vibratory assembly is ineffective when applied to yielding materials and furthermore, requires a fairly open site whereby the interposition of the slurry between the vibrating tool tip and the work surface can be maintained at all times during the procedure. Moreover, separate means are required for the collection and removal of the spent slurry and debris, and the workpiece generally requires a flushing or washing to clean up the residual abrasive particles tending to adhere to it. U.S. Pats. Nos. 3,075,288, 3,076,904 and 3,213,537 involve high frequency vibratory instruments for particular use in the dental field. The instruments described in these patents do not necessarily require a source of abrasive particles, as described above in respect to industrial equipment. Also, these dental instruments do not have any means for removal of the particles created as a result of the high frequency vibrations, hence would be entirely inapplicable for use in inaccessible places.

The instrument described herein thus lends itself to the performance of delicate surgical procedures in extremely limited areas. One such surgical procedure, for which the instrument has proven especially effective, is the removal of cataracts from the eye. A cataract operation requires total removal of the clouded lens which is usually accomplished by a 180.degree. incision in the cornea, which is then lifted up to remove the clouded lens in one piece. The inventive instrument of this application obviates the need for such an incision requiring only one incision in the form of a small aperture to allow the operative end of the instrument to be inserted within the eye.

The primary object of the present invention is to provide a vibratory instrument and method which are effective to break apart and remove soft, yielding material without the use of an auxiliary cutting medium and which is particularly adapted for use in restricted, enclosed sites, such as are encountered in surgical procedures.

It is a further object of the present invention to provide a vibratory instrument including a portion readily held and controlled by the human hand which is particularly adapted for use in surgical procedures.

Still another object of the present invention is to provide an instrument including a handpiece having an operative tip capable of vibrating at ultrasonic frequencies with minute amplitudes and having both a source of fluid and a pumping line adjacent its working end, whereby particles of the material to be removed are dispersed within the fluid and withdrawn from the operative site through the pumping line as they are produced so that further cleaning is unnecessary.

Another object of the present invention is to provide suitable power and fluid supplies and pumping means for use with such a handpiece, together with switch means for their control.

A further object of the present invention is to provide various operative tip configurations for use with such a handpiece whereby removal of materials from relatively inaccessible locations is facilitated.

Briefly, the present invention comprises an apparatus having a casing in which is mounted a vibratory assembly for converting electrical energy into high frequency mechanical vibrations which are used to break apart the unwanted tissue. Within said casing there is also a first passage for carrying a treatment fluid to the region where the vibrations are applied and a second passage for carrying a suspension of unwanted material in said treatment fluid away from said region which constitutes the above-mentioned inaccessible place. The apparatus also includes a means for supplying electrical energy to said vibratory assembly for the energization thereof and a means for supplying the treatment of fluid to said first passage and a means of withdrawing said suspension from said second passage.

More specifically, the casing is adapted to be held in the hand, and the vibratory assembly includes a transducer, such as of the magnetostrictive or piezoelectric type, a removable operative tip and a connecting body in the form of an acoustic impedance transformer for supporting the operative tip and coupling the high frequency vibrations thereto.

The requisite electrical power together with a supply of coolant for the transducer is connected to the housing at the transducer end. A supply of treatment fluid, such as a liquid providing a dispersion medium for the particles to be removed, is coupled through a first passage provided in the housing to an outlet adjacent the operative tip. A source of suction, provided by a suitable pumping means, is coupled via a second passage within the housing to a point adjacent the operative tip.

In using the instrument, alternating electrical energy is applied to the transducer to set the operative tip in vibratory motion. As the operative tip is applied to the material, the region adjacent the operative site is bathed or flooded with the treatment fluid while the pumping means is activated to withdraw fluid with suspended particles therein from the region.

The high frequency action of the small area output end of the operative tool tip against the material to be removed rapidly breaks it apart into tiny particles, dispersion of which in the fluid medium is enhanced by the vibratory forces engendered in the medium. The pumping means is then effective to withdraw the resultant suspension from the region of operation. The material to be removed is not only broken apart into small particles, but completely withdrawn from its original location. No subsequent flushing or aspiration procedures are necessary.

In order to keep the incision into the cornea as small as possible, the operative tip has a bore through its center forming a part of one of the passages and there is a tubular sleeve coupled to the casing, surrounding a portion of the operative tip to form an annular space thereabout which is part of the other of said passages.

In order to simplify the problem of changing the operative tips during an operation, the front portion of the casing, referred to as a tubular sleeve, is readily removable to provide access to the operative tip which is also removable from the remaining portion of the vibratory assembly. This tubular sleeve includes a sheath which is composed of a plastic material. Since this sheath is quite small in diameter, in order to minimize the size of the incision, it would be very difficult to manufacture it from any metallic substance and maintain the proper tolerances to provide for the annular space between it and the operative tip. Also, the resiliency of plastic is necessary to avoid any substantial dampening effect on the vibratory assembly should the sheath contact the operative tip. The heat resistant nature of the plastic material also avoids the transmission of any heat to the cornea from the sheath.

For proper operation of the instrument it is necessary to have certain valve and switch means for selectively operating the source of electrical energy, withdrawal means and a line to atmospheric pressure. This is particularly important with respect to an operation in the eye, since it is extremely important to be able to maintain the fluid pressure within the eye within certain limits.

Finally, the vibratory assembly must be supported in some manner within the casing and this is effected by the use of resilient sealing means, an example of which are rubber O-rings. These sealing means serve the dual purpose of supporting the vibratory assembly at approximately a node of longitudinal motion so as to have a minimum effect on dampening the motion and also serve to define one of the fluid passages.

The foregoing and other objects, features and advantages of the invention will become apparent from the following more detailed description thereof when taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a pictorial representation of the entire instrument of the invention showing, in perspective, the handpiece and the supporting equipment;

FIG. 2 is an enlarged pictorial representation of the tool tip shown in use, to aid in explaining its action;

FIG. 3 is a view, mostly in cross section, of the handpiece of the invention showing its internal construction;

FIG. 3A is an enlarged cross-sectional view of the tip end of the handpiece of FIG. 3;

FIG. 4 is an enlarged pictorial representation of the top of the handpiece showing the use of the instrument in cataract removal;

FIGS. 5A through 5I show various forms of operative tips for use with the instrument; and

FIG. 6 is a schematic diagram of the foot switch control means for the oscillator and pump valves.

In the ensuing detailed description, the invention will be described in terms of its use as a surgical instrument, particularly as applied to cataract removal. However, it will be understood that the principles of the invention are not so limiting, and the apparatus described is capable of a wide variety of material breaking and removal applications, within and outside the medical field.

Turning now to FIG. 1, the elements of the instrument of the invention include a handpiece indicated generally at 10, which is of a size and weight as to be comfortably held in the hand and easily manipulated by the user. As will be described in connection with FIG. 3, the handpiece 10 includes within its outer housing or casing, transducer means for converting high frequency electrical energy into mechanical vibrations of high frequency and small amplitude. The requisite high frequency alternating current electrical energy is supplied by a conventional oscillator included in the unit indicated generally at 12. Insofar as ability to perform tissue removal is concerned a wide range of frequencies is suitable, for example from 1,000 to 100,000 cycles per second. However, a convenient choice of frequency has been found to be approximately 25,000 cps which permits optimum selection of handpiece components, both with respect to overall size and effectiveness, and also is above the range of human hearing, eliminating annoying audible effects obtained at lower frequencies.

The output of the oscillator in unit 12 is connected by a pair of leads enclosed within the conduit 14 and coupled through the end of the handpiece remote from the operative tip. As indicated on the face of the unit 12, the oscillator is provided with suitable frequency and amplitude controls, whereby the precise frequency of operation may be tuned over a range and the amplitude of the electrical signals also may be varied. These controls enable tuning of the instrument to resonance and adjustment of the vibration amplitude of the operative tip, in accordance with the needs of the user.

The unit 12 also provides a source of cooling water for the handpiece which ordinarily is required to carry away the heat generated by the electrical-to-mechanical energy conversion occurring in the handpiece. For this purpose, the conduit 14 also carries a pair of flexible tubes, one for carrying the coolant into the handpiece end and the other for withdrawing the coolant therefrom. This provides a circulating system for maintaining the temperature of the handpiece at comfortable levels. Unit 12, as illustrated, is provided with a water control valve for adjusting the cooling flow. The coolant may be obtained from a convenient tap or may be incorporated in a closed circulation system having a small pump and a cooling system for the coolant returned from the handpiece.

The supporting equipment for the handpiece further includes a pump 16 (to be referred to as a withdrawal means) and a treatment fluid supply 20. The pump is coupled via conduit 18 and through an opening in the housing of the handpiece to the interior thereof. In addition to providing a source of suction force for the withdrawal of unwanted particles suspended in the treatment fluid, the pump includes valve means whereby the conduit 18 may be selectively coupled to the pump or opened to atmospheric pressure.

The treatment fluid supply 20, which may include a reservoir of a premixed solution of appropriate type and a suitable pump, or mixing means whereby the required solution is prepared on a continuous basis, is connected through conduit 22 and into the interior of the housing of the handpiece. As will be described in greater detail hereinafter, the handpiece includes internal fluid passages coupled to the conduits 18 and 22 whereby, at the operative tip of the instrument, there may be provided both a flow of treatment fluid and a withdrawal of unwanted particles suspended in the treatment fluid.

A switch 24 is provided to enable control of the oscillator and pump during manipulation of the handpiece by the surgeon. The switch 24 may be of any convenient type, preferably resting on the floor and including a control lever 25 adapted to be actuated by the foot selectively between several positions. The switch is coupled via conductors 26 to the oscillator housing 12 and the vacuum pump 16 to control the components thereof, as will be described more fully hereinafter.

The manner in which the instrument is used for tissue removal is illustrated in FIG. 2. In the drawing, 32 indicates a cohesive mass (as distinguished from a collection of discrete particles) of undesired tissue located within a region of healthy tissue 30 below the skin 34. To remove the tissue 32 with the present instrument, a small surgical incision 36 is made through the skin adjacent the mass 32 to enable the operative tip of the handpiece 10 to reach the tissue mass 32. As the tip of the handpiece 10 is inserted through the incision 36 and into contact with the unwanted tissue, the surgeon actuates the foot switch 24 to apply alternating current power to the instrument to set the tip into vibration and also to actuate the pump 16.

At the same time, the treatment fluid supply is turned on, at controlled pressure, so that at the operative tip of the tool which is brought into contact with the mass 32, three conditions simultaneously obtain. Firstly, the operative tip vibrates at a high frequency rate and with small amplitude against the tissue mass 32 and in the process breaks it apart into minute particles. Concurrently, the treatment fluid supply, which preferably is a solution compatible with the animal tissue being treated (such as saline), floods or bathes the region at the tip end which is being subjected to the vibratory action. Finally, the suction source at the operative tip simultaneously withdraws from the operative site the resultant suspension of the small particles of removed tissue in the treatment fluid bathing the area. The unwanted tissue thus separated from the host body is removed as it is broken apart and, at the same time, leakage of the treatment fluid outside of the operative site is minimized. An equilibrium condition thus exists at the operative site between the treatment fluid, the withdrawal means, and the small leakage.

In employing the instrument as shown in FIG. 2, the surgeon manipulates the handpiece 10 until all of the unwanted tissue has been broken apart and removed from the operative site. If necessary, additional small incisions 36 may be made at various other surface points to permit ready access to the mass of unwanted tissue. However, each of these incisions need be only sufficiently large to admit the slender operative tip of the instrument. This reduces trauma and speeds recovery time, as compared to a massive surgical excision by the usual procedures.

Although the exact mechanism occurring at the working end of the operative tip, which results in breaking apart of the tissue mass into minute particles, is not fully understood at present, it is believed to be a composite of a cutting action by the relatively sharp tip and a fracturing resulting from the large number of impacts of the vibrating tip. Regardless of precisely how the tissue is fragmented, it has been found that the instrument of the invention effectively breaks apart tissue into minute particles, sufficiently small to pass readily through an opening in the operative tip less than 1 millimeter in diameter.

The handpiece itself is shown in cross section in FIGS. 3 and 3A. Substantially all of the operative parts of the handpiece are enclosed within a casing indicated at 40, which includes a generally tubular barrel section 40a, a smaller diameter extension section 40b threaded onto the forward end of the barrel 40a, a forward end cap 40c having a small diameter tubular portion extending therefrom (see FIG. 3A) threadedly engaging the forward end of extension 40b, and a rear closure 40d threadedly engaging the rear portion of the barrel 40a. Preferably, all of the portions of the casing 40 are made of a metal such as stainless steel, which is sterilizable and which also provides shielding for the electrical and magnetic components within the handpiece.

The vibratory assembly contained within the casing 40 is composed of a transducer portion 42 and a connecting body 46, the latter preferably in the form of an acoustic impedance transformer. The transducer element 42 may be of any suitable type capable of converting high frequency alternating current signals into corresponding longitudinal mechanism vibrations. In the embodiment illustrated, the transducer is composed of a stack of thin sheets of magnetostrictive material such as nickel, Permendur, or other similar material, insulated from each other and firmly secured together such as by brazing at the ends. As shown, the stack is divided by a lengthwise elongated opening effectively separating the stack into two separate vibratory sections, with the coil 44 wound about each section or leg separately, in such fashion as to produce in phase vibration in both legs.

The forward end of the stack 42 is coupled, such as by a threaded connection as shown or by a permanent bond, to the input end of the connecting body 46. Preferably, a washer 43 is provided between the end of the stack and the input surface of the member 46 to render the transmission of vibratory energy to the member 46 more effective.

As indicated above, the connecting body 46 preferably is in the form of an acoustic impedance transformer whereby the amplitude of the longitudinal vibrations induced in the stack 42 may be increased for application to the operative tip of the handpiece. For this purpose, the member 46 may be of the type shown in U.S. Pat. No. 25,033, assigned to the present assignee, formed of a single piece of vibration transmitting material such as Monel metal, having a relatively massive input section 46a and a relatively slender output section 46b, with a tapered transition region 46c. As described in the aforementioned reissue patent, maximum amplification of longitudinal vibrations in such a member occurs when both the input and output sections of the transformer are equal in length to one-fourth of the wavelength in the material at the frequency of vibration and each of said sections is substantially uniform along its length in cross-sectional area.

However, in many applications, including use in surgical procedures such as described herein, sufficient amplitude of vibration may be obtained under less than maximum amplitude conditions. Accordingly, it will be understood that a relatively wide variation in dimensioning of the impedance transformer 46 is permissible to allow the instrument to perform its intended function effectively. In fact, many different types of connecting bodies may be employed.

As described in the aforementioned patents of the present assignee, optimum energy conversion in the magnetostrictive transducer 42 is obtained when the longitudinal dimension of the stack is equal to a half wavelength in the material at the applied driving frequency. Considering, then, the overall vibrating structure consisting of the stack 42 and the impedance transformer 46, it will be seen that, ideally, the combined length would be equal to a full wavelength at the operating frequency, with each of the stack and transformer being equal to a half wavelength. This would place loops of motion at the free ends of the stack and transformer, as well as the juncture of the two components, where a minimum stress point would therefore occur.

At the same time, nodes of longitudinal motion would occur approximately midway along the length of the stack 42 and approximately at the junction of the input section 46a and output section 46b of the transformer. The effects of the high stresses at the junction are minimized by providing the tapered transition 46c.

As described in the aforesaid patents, support of such a vibratory structure is best achieved by mounting means located approximately at a node of longitudinal motion whereby minimum damping of such motion results. In FIG. 3, such mounting means are provided in the form of a pair of resilient rings, generally referred to as "O" rings, located in a pair of spaced grooves extending circumferentially around the input section 46a of the transformer, as close as possible to the transition region where the nodal plane would be located. The rings 48 and 50 are of such diameter that they effect a fluidtight seal between the surface of the transformer input section 46a and the inner wall of the housing barrel 40a.

In addition to the spaced sealing rings 48 and 50, a plurality of screws 52 are provided angularly disposed about the axis of the casing, for the purpose of preventing longitudinal or rotational movement of the vibratory structure within the casing and also for radially centering the vibratory structure within the casing. By adjusting the several screws, concentricity of the interior elements of the handpiece and the casing sections may be obtained.

The sealing rings 48 and 50 divide the interior volume of the housing 40 into three independent fluid chambers. The ring 48 in conjunction with the end closure means to be described hereinafter will form a first chamber in which are disposed the magnetostrictive stack 42 and a portion of the transformer input section 46a. An annular chamber of relatively short axial dimension is formed between the two O-rings 48 and 50, and a third chamber is formed forwardly of the ring 50 including the free space within the casing extension 40b.

The rear portion of the casing barrel 40 is sealed off by means of a grommet 55 which is press fitted into the end of the barrel to form a watertight seal therewith. The grommet is provided with openings through which the electrical leads 45 pass from the conduit 14 to the coil 44. In addition, a coolant fluid inlet tube 54 passes through the grommet 52 and extends within the barrel 40a to a point adjacent the forward end of the stack 42. Fluid outlet tube 56 is also passed through the grommet 52 and into the conduit 14 along with the tube 54. The cooling water supply continually flows into the chamber enclosing the magnetostrictive element from the tube 54, and is withdrawn through the outlet tube 56 after passing over the heat producing elements. It will be understood that the leads 45 and conduits 54 and 56 pass through the grommet 52 in fluid tight relationship.

To provide strain relief for the conduit 14 and minimize entanglement, a wire coil 15 may be wrapped around the portion of the conduit 14 adjacent the handpiece, in place of the plastic tubing enclosing the remainder of the conduit. The coil 15 engages a helical groove provided internally of a retaining element 41. The latter element is compressed about the coil 15 and firmly retained against movement by the threaded cap 40d.

The impedance transformer 46 is provided with an axial bore 47 extending from the free or forward end of the output section 46b and into the input section 46a, to a point between the two sealing rings 48, 50. A radial bore 47a connects the bore 47 to the periphery of the transformer 46 and into the annular chamber between the sealing rings. Nipple 56 is connected to the periphery of the handpiece barrel 40a and is provided with an internal bore extending through the casing and communicating with the annular chamber between the rings 48 and 50 and thus with the bore 47 via the radial bore 47a.

A second nipple 58 is connected to the casing extension 40b at a point near its threaded coupling to the barrel 40a. The latter nipple includes an internal passage communicating with the annular chamber extending forwardly of the sealing ring 50 and including the space between the impedance transformer 46 and the inner walls of the casing sections. As shown best in FIG. 3A, this latter chamber extends past the free end of the output section of the connecting body 46b and through the cap 40c.

The operative tool or tip which actually comes into contact with the material to be broken apart and removed is designated by the numeral 60. Referring to FIG. 5A, the tip 60 is elongated and provided with a thickened shank portion 60a which preferably is formed with at least a pair of flats to accommodate a wrench for tightening. A threaded connection portion 60d is formed integrally with the base portion 60a, and a washer 60c, of efficient vibration-transmitting material, is disposed adjacent the shoulder between the portion 60a and 60b. The other end of the tip 60 is shaped in a manner dependent upon the particular type of material or tissue to be broken apart and removed and the shape of the portion to be removed or its surrounding material. In FIG. 5A an acute-angled taper is provided to leave a relatively sharp, rounded edge 60d. An axial bore 60e extends completely through the tip 60 to provide a fluid passage from threaded end 60b to the outer or working end of the tip.

Referring back now to FIG. 3A, the bore 47 in the transformer 46 is provided at the free end of the output section with internal threads adapted to receive the threaded portion 60b of the tip 60. To attach the tip 60, or to replace one already in position, the end cap 40c is threadedly disengaged from the casing extension 40b and slid backover and away from the tip 60. A small wrench may be used to engage the flats on the base section 60a to remove a tip already in place or to snugly insert a new tip. The end cap 40c is then replaced and the tool is assembled for use.

The operative tip 60, being firmly coupled to the output end of the impedance transformer 46, will be longitudinally vibrated thereby at the operating frequency and essentially with the amplitude available at the end of the output section 46b. The operative tip 60 preferably is formed of an extremely hard, sterilizable material, such as titanium, and for most surgical applications is made of extremely small dimension. For example, in the instrument as used for cataract removal operations, the operative tip had an outside diameter of approximately 1 millimeter. Since this is the only portion of the instrument that is brought into contact with the tissue to be broken apart and removed, it will be evident that only a very short incision need to made in the outer surface to permit access of the tip.

Where the material to be broken apart and removed is relatively deep below the surface, it is undesirable for the shank of the operating tip to be brought into contact with the surrounding tissue, especially if that tissue is healthy and not to be removed. Since the tip 60 is vibrating at a high frequency, heat will be developed due to the rubbing action and damage to delicate tissues can result.

To avoid this possibility, a sheath 64 of a strong, heat-resistant and inert material, such as the plastic known as "Teflon", is provided. As shown best in FIG. 3A, the sheath 64 is provided with an axial bore of a diameter somewhat greater than the outer diameter of the tip 60 and has a base section with a counterbore that snugly engages the tubular portion extending from the forward end of the end cap 40c. The fit between the latter two parts is made such that the sheath 64 may be secured to the end cap 40c with manual pressure but will not shake loose under normal usage.

The barrel of the sheath 64 extends along a considerable length of the operative tip 60 and has an outer diameter of sufficient thickness to provide the necessary structural rigidity. Preferably, it is slightly tapered, as shown. The annular clearance between the inner surface of the sheath 64 and the outer surface of the operative tip 60 serves as an extension of the fluid passage formed between the transformer section 46b and the casing extension 40b.

As will be explained in greater detail in connection with FIG. 6, alternating current electrical energy having a superimposed direct voltage bias thereon is coupled from the unit 12 and via conductors 45 to the coil on the transducer 42. The vibratory structure is thereby set into longitudinal vibration at the oscillator frequency, with the consequent vibration of the operative tip 60. For purposes of example, the amplitude of the alternating current supply may be set such that the working end of the tip 60 has a stroke amplitude of approximately 0.003 inch. At the same time, of course, a coolant supply is circulating in the chamber housing the transducer structure.

As the operative tip is brought into contact with the material to be broken apart and removed, treatment fluid from the supply 20 is provided through the conduit 22 and the nipple 58 to the passage formed between the connecting body 46 and the casing extension 40b and thence through the annular space between the cap 40c, sheath 64, and the tip 60. The tissue adjacent the operating tip is thereby bathed with the treatment fluid.

The treatment fluid serves two purposes. In addition to maintaining the operative tip relatively cool during use, thereby reducing possible harm to healthy tissue, it provides a dispersion medium in which particles of tissue are suspended as they are broken away from the tissue mass. It will of course be realized that the treatment fluid is being brought into direct contact with delicate tissue and accordingly must be of a neutral nature. In the case of cataract removal, for example, a balanced isotonic saline solution is suitable for this purpose.

Withdrawal of the suspension of the tissue particles in the treatment fluid is effected through the hollow operative tip, the bore 47 in the transformer 46, the connecting passage 47a and nipple 56, through the conduit 18 and to the withdrawal means, for example a pump 16. During the operative procedure, the volume of treatment fluid supply is controlled, along with the pump operation, so that a proper amount of treatment fluid is maintained at the operative site and overflow is minimized.

The use of the instrument of the invention as applied to cataract removal is illustrated in FIG. 4. A portion of a simplified cross section of a human eye is shown to illustrate the manner in which the device is employed. The opaque lens or cataract which is to be broken apart and removed to is designated by the numeral 72 and is encased in a membrane including an outer portion 72a known as the anterior capsule and a rear portion 72b known as the posterior capsule. The iris is designated by the numeral 74 and the major gel-filled portion of the eye, or vitreous, is shown at 76. The cornea, the transparent outer surface of the eye, is shown at 70.

To avoid having to pierce or cut the iris, suitable drugs are administered to dilate the iris to its maximum extent, so that as much of the anterior capsule 72a is exposed as is possible. A small incision 78 is then made in the transparent cornea fluid as far as possible from the center of the pupil area. This incision need only be about 1 to 3 mm. in length to provide proper access for the operative tip of the vibratory assembly.

The anterior capsule 72a is penetrated, first, either by the operative tip of the vibrating assembly or with a surgical instrument. Once an opening in the anterior capsule has been made, such as indicated in FIG. 4, the operative tip is inserted into the body of the cataract 72, whereby the lens tissue mass is broken apart into minute particles. During this portion of the operation, the transducer is energized and the pump is activated to provide suction force at the operative tip, along with a supply of treatment fluid.

In the space of a few minutes, all of the cataract tissue 72 is broken apart and the particles, together with the fluid in which they are suspended, withdrawn by the instrument. Thereafter, the remnants of the anterior capsule and the posterior capsule are withdrawn with capsule forceps. This completes the cataract removal. The small incision 78 is subsequently sutured to conclude the surgical procedure. As compared to the conventional cataract removal, which requires a 180.degree. incision around the cornea, trauma to the patient and recovery time are substantially reduced.

In FIG. 4, the operative tip of the vibratory assembly is illustrated as inserted into the eye with the plastic sheath 64 in place. As the surgeon maneuvers the instrument to reach all of the cataract tissue, any contact that occurs between the instrument and the other parts of the eye is on the sheath, which is not vibrating and therefore cannot damage any of the delicate tissue. In this instance, the sheath also serves to discharge the treatment fluid more directly at the operative site. It will be understood of course, that the sleeve 64 may be removed and the operative tip employed without it where operative conditions permit.

In the cataract removal procedure, the treatment fluid supply serves a purpose in addition to providing a dispersion medium for the particles of unwanted tissue and a coolant for the operative tip, by serving to maintain sufficient pressure within the anterior chamber of the eye, between the anterior capsule 72a and the cornea 70, whereby collapse of the latter is avoided.

The operative tip 60 shown in detail in FIG. 5A is but one of a number of different forms of operative tip that may be employed with the instrument of the present invention. When used for cataract removal, it will be seen that the straight tapered tip shown in FIG. 5A will not be able to reach all of the lens tissue within the lens membrane without incurring the danger of piercing the vitreous. To clean out the portions of the lens tissue clinging to relatively inaccessible corners of the lens membrane, operative tips having other shapes are employed. Several possible configurations for this and other purposes are shown in FIGS. 5B to 5I.

FIGS. 5B and 5C illustrate, respectively, a symmetrically straight tapered tip end and a symmetrically rounded taper tip end. FIGS. 5D and 5E are two views of a tip having a relatively blunt end and an opening angled to the axis of the main portion of the tip to provide a spoon shape. Such a tip is used to reach the inaccessible corners of the lens capsule without risking damage to or possible puncture of the vitreous.

FIGS. 5F and 5G and FIGS. 5H and 5I show two additional forms of operative tips, each of which incorporates a sharp projection such as might be used for puncturing the anterior capsule of the eye.

The forgoing tip designs represent but a few of the many possible variations which may be employed in the large number of tissue breaking apart and removal applications that can be accomplished with the present instrument.

A suitable switch control a arrangement for the oscillator and coolant supply 12 and the pump 16 (FIG. 1) is shown in FIG. 6. The pump 16 includes two input lines, 80 and 82, and a discharge line 92 to a drain or waste line. The pump preferably is of the continuous acting type and therefore is either pumping fluid from a sump or reservoir through input line 80 or from the operative site through the handpiece and conduits 18 and 82. Control of the conduits 80 and 82 is effected by solenoid valves 86 and 88 respectively, so that the pump is pulling fluid through one or the other at any given time.

Under certain conditions, during the course of surgical procedures, it may be desired not to withdraw fluid from the operative site, but merely to maintain a static pressure condition thereat. For this purpose, an additional conduit 84 is coupled to in the input line 82 under control of an additional solenoid valve 90.

The switch 24, having a foot-actuated control arm 25, not only controls the operation of the pump 16 but also the application of energy from the oscillator in unit 12 to the coil on the handpiece transducer. As shown in FIG. 6, the switch has three positions, A, B, and C, the position A having a pair of spaced contacts 94, the position B having a pair of spaced contacts 96, and position C having two pairs of spaced contacts 98 and 100. The switch arm 25 is pivoted at one end and includes a pair of spaced conductive segments 25a and 25b, separated by insulating material. When in position C, as shown in the drawing, the segment 25a bridges the contact pair 98 while the segment 25b bridges the contact pair 100. In positions A and B, the segment 25a bridges the contact pairs 94 and 96 respectively.

A source of operating voltage 102 is coupled to one contact of each of the contact pairs 94, 96 and 98. The other contact of contact pair 94 is coupled to the inputs of both solenoid valves 86 and 90. The other contacts of pairs 96 and 98 are connected in common to the control input of solenoid valve 88. The contact pair 100 interrupts a lead from the oscillator 12 to the handpiece whereby energy is delivered to the latter only when the segment 25b bridges the contact 100, as shown.

The switch arm 25 is spring urged, such as by a coil spring 104, so that its normal position is in position A, bridging contacts 94. Each of the solenoid valves 86, 88 and 90 are normally in their closed position, that is, with no electrical power supplied to their control inputs, they close the channels in which they are interposed.

With the switch are in position A, the contacts 94 are bridged, permitting connection of the source 102 to both valves 86 and 90. These two valves are thus opened, connecting the pump input to the reservoir or sump and opening the conduit 18 to atmospheric pressure. The valve 88 remains closed.

With the switch arm in position B, bridging contacts 96, valve 88 is opened while valves 86 and 90 remain closed. The pump 16 then is coupled directly to the conduit 18 and thus provides a suction force at the tip of the handpiece. It will be noted, that in both positions A and B, the output of the oscillator 12 is not connected to the handpiece and consequently, the operative tip 60 is not set into vibratory motion.

With the switch arm in position C as shown, valve 88 is opened, valves 86 and 90 are closed and the biassed alternating current output of the oscillator is coupled to the handpiece. This establishes the full operative condition of the handpiece, i.e., high frequency vibration of the operative tip and the establishment of a suction force to withdraw fluid from the operative site.

During the operative procedure, control of the treatment fluid supply will be maintained preferably by an assistant to the operating surgeon. Depending upon his needs at the moment, the surgeon will direct the assistant to control the pressure of the fluid supply, between an "Off" or no supply position and a "High" condition, under which maximum flow into the operative site is obtained. (See FIG. 1). At the same time, the amplitude of the oscillator output will be controlled to produce the proper stroke amplitude at the operative tip. Adjustment of the latter is desirable to permit both removal in gross of unwanted tissue as well as the cleaning up of small bits of material where care must be exercised to avoid damaging surrounding tissue.

It will be apparent from the foregoing, that a novel, improved form of material breaking apart and removal apparatus has been disclosed, by means of which unwanted material, such as animal tissue, may be broken apart into minute particles and removed rapidly and with a minimum of damage to surrounding materials. By virtue of the controlled fluid supply and pump, material may be removed from the operative site as it is broken apart thereby eliminating the necessity for subsequent cleansing operations and minimizing obscuring of the operative site during the procedure.

It will also be recognized that many variations of the particular apparatus disclosed will occur to those skilled in the art, without departing from the spirit of the invention. For example, the flow passages for the treatment fluid supply to the operative site and the withdrawal of the suspension from the operative site may be interchanged, such that the fluid is transmitted through the hollow operative tip and withdrawn through the annular space between the tip and the sleeve 64. Moreover, more sophisticated control arrangements for the oscillator pump and treatment fluid supply may be employed and various other tip shapes are possible, within the teaching of the present invention. Accordingly, the invention is to be deemed limited only by the scope of the appended claims.

Claims

We claim:

1. Apparatus for the breaking apart and removal of animal tissue from an enclosed area, an elongated working tip adapted to have one end placed directly against the tissue and capable of supporting ultrasonic vibrations, means for applying ultrasonic vibrations of variable amplitude and duration to said working tip, means for supplying a treatment fluid to bathe said tissue in the region adjacent said working tip, and pumping means adjacent said working tip for withdrawing the suspension of particles of said tissue of said fluid resulting from ultrasonic vibration of said working tip.

2. Apparatus for the breaking apart and removal of animal tissue and the like comprising, an elongated, hollow working tip adapted to have one end placed against the tissue to be removed and capable of supporting ultrasonic vibrations, means for applying ultrasonic vibrations to said working tip, means including a tubular sleeve surrounding a portion of said working tip for providing a first fluid passage between said tip and a point remote therefrom, means coupled to said tip for providing a second fluid passage between the hollow interior of said tip and a point remote therefrom, means for supplying a fluid to one of said passages and means for applying a suction force to the other of s aid passages.

3. A surgical instrument adapted to be held in the hand and moved freely during operative use comprising, a casing of size and configuration comfortable to the hand, transducer means within said casing for generating high frequency mechanical vibrations upon excitation with a high frequency alternating current electrical signal, an operative tool external of said casing and coupled to said transducer means to be vibrated thereby, a first fluid passage extending through said casing and in surrounding relation to at least a portion of said operative tool, and a second passage formed in part internally of said operative tool and extending into said casing, one of said passages being adapted to conduct a fluid to said operative tool and the other of said passages being adapted to withdraw fluid from the region adjacent said operative tool.

4. Apparatus according to claim 3 above wherein said operative tool is elongated and formed with an axial bore providing a part of said passage.

5. Apparatus according to claim 3 above wherein said casing includes an extension surrounding and spaced from the peripheral surface of a portion of said tool, the space between the inner surface of said casing extension and said peripheral surface of said took providing a part of said first passage.

6. Apparatus according to claim 3 wherein said transducer means includes an acoustic impedance transformer having a relatively massive input section and a relatively slender output section, said output section extending within said casing extension and being coupled at its free end to said tool, said output section having a cross-sectional area smaller than the internal cross-sectional area of said casing extension, the spacing therebetween forming a continuation of said first passage, said transformer further having an axial bore extending from the free end of said output section to a point within said input section, and a radial bore from said axial bore to the periphery of said input section, said axial and radial bores forming a continuation of said second passage.

7. Apparatus according to claim 6 above further comprising a pair of spaced-apart resilient sealing means around said input section of said transformer within said casing, each of said sealing means providing a circumferential fluidtight seal between said input section and said casing, the peripheral opening of said radial bore being between said sealing means.

8. Apparatus according to claim 6 above further comprising a first opening in said casing located between said sealing means, a second opening in said casing located between said casing extension and the sealing means closest to the output section of said transformer, and means mounted exteriorly of said casing adjacent each of said openings adapted to be connected to a fluid conduit.

9. A surgical instrument for breaking apart and removing unwanted material comprising, a handpiece including transducer means for converting high frequency alternating current into high frequency mechanical vibrations, an operative tip coupled to said transducer means to be vibrated thereby, said tip having an axial bore therethrough defining a first passage sleeve means surrounding and spaced from said tip defining a second passage, a source of high frequency alternating current coupled to said transducer, a source of treatment fluid coupled to one of said passages, pumping means coupled to the other passage for withdrawing a suspension of unwanted material in said treatment fluid, and switch means for controlling the application of said alternating current and the suction force provided by said pumping means to said handpiece.

10. The apparatus of claim 9 further comprising valve means interposed between said pumping means and said handpiece, and control means for said valve means for selectively coupling the axial bore in said tip to said pumping means or to atmospheric pressure.

11. The apparatus of claim 10 wherein said switch means includes a control member selectively movable between a first position in which no alternating current is supplied to said transducer means and said valve control means couples the axial bore in said tip to atmospheric pressure, a second position in which no alternating current is supplied to said transducer means and said valve control means couples the axial bore in said tip to said pumping means, and a third position in which alternating current is supplied to said transducer means and said valve control means couples the axial bore in said tip to said pumping means.

12. The apparatus of claim 9 wherein said sleeve means includes a readily removable sheath extending to a point closely adjacent the free end of said operative said sheath being formed of a relatively hard, heat resistant, plastic material.

13. The apparatus of claim 3 wherein said casing is formed of a material providing a magnetic and electrical shield for the components enclosed therein.

14. The apparatus of claim 9 wherein said source of fluid includes control means for maintaining the pressure of said fluid at a level such that an equilibrium condition between supply and removal of fluid at the operative site may be maintained.

15. Method for the breaking apart and removal of a cohesive mass of unwanted material from an enclosed area comprising the simultaneous steps of, applying high frequency vibrations directly to the unwanted material to reduce said mass of material to small particles, bathing the material in the region in which said vibrations are applies with a treatment fluid, and withdrawing the resulting suspension of particles in said treatment fluid.

16. Method for the breaking apart and removal of animal tissue and the like from an enclosed area, employing an elongated working tip comprising the simultaneous steps of, applying ultrasonic vibrations of variable amplitude and duration to said working tip in contact with said tissue, supplying a treatment fluid to bathe said tissue in the region adjacent said working tip, and withdrawing the suspension of particles of said tissue in said fluid so that the pressure within the enclosed area is controlled.