PHACO-EMULSIFICATION APPARATUS AND METHOD

Abstract: An apparatus for phaco-emulsification and extraction of cataractous lens (L) tissue includes a hollow probe (18) having at its proximal end a connection to a laser source (16), the radiation passing through focussing (22) and collimating (24) lenses and passing non-axially into the probe (18). Inlets and outlets at the proximal end of the probe (18) are connected to separate metering infusion (30) and extraction (50) pumping systems. Laser radiation is applied to the tissue through a bubble or sphere (S) of saline solution formed at the distal end of the probe (18). A method in which a measured amount of saline solution is caused to form a small sphere (S) within tissue, ablative laser energy is applied to the adjacent tissue through the sphere (S) to effect phaco-emulsification, the emulsified tissue and solution being then extracted.

Description: PHACO-EMULSIFICATION APPARATUS AND METHOD BACKGROUND OF THE INVENTION This invention relates to a method and apparatus for the emulsification of tissue, such as a cataractous lens, by the application of laser energy, and the extraction of emulsified tissue. The lenses of the human eye are subject to a deterioration known as cataracts, which obstructs the vision. Correction of this condition has been by removal of the lenses, and the providing of auxiliary lenses such as eye glasses, contact lenses, and/or implanted lenses following lens extraction. An early method of lens extraction was the freezing of the lens, and its removal as a substantially unitary and solid body. This method has generally been replaced by phaco-emulsification, in which a small needle-like probe is introduced into the lens, and vibrated to change the lens to an emulsion of sufficiently gel or fluid character that it can be extracted through a hollow probe having very small internal and external diameters. Typically, the same probe which is vibrated to cause emulsification is used for extraction of the emulsified lens. There are disclosed in the prior art a number of applications of laser energy to cataract tissue. L'Esperanσe, Jr. U.S. Patent 3,982,541 provides an instrument in which laser energy from a carbon dioxide laser is applied to the surface of cataract tissue, which is vaporized by the laser beam, with smoke and vaporized portions of the tissue being withdrawn by vacuum pump. Eisenberg U.S. Patent 4,559,942 points out defects of phaco-emulsification by ultrasonic vibration, and reports on intra-ocular photo-coagulation methods involving an argon laser system and a Xenon arc. Eisenberg teaches using a carbon dioxide laser and a hollow probe, and injecting a controlled volume of air through the probe to form a small air bubble, with a pulse of radiation being passed through the probe and the air bubble to the adjacent tissue. The purposes are to achieve photo-coagulation such as the production of a lesion on the retina, the apparatus also being used for photo-cauterization and photo-incision, as well as for cataract emulsification. The provision of an air bubble results in undesirable optical discontinuities, with consequent scattering of the radiation and a cutting action which is less effective than is desirable. Further, since air is compressible, the quantity of air and therefore the size of the bubble is difficult to control, and no indication is given in Eisenberg f s disclosure how the size of the air bubble is established by the apparatus broadly disclosed. The utilization of a Neodymium YAG carbon dioxide laser, or its equivalent, due to low absorption in tissue might enable the radiation to penetrate through the lens and possibly onto other parts of the eye; apparently to diminish that risk, in one embodiment. Eisenberg provides a shield to protect the cornea from the radiation. This increases the complexity of the instrument and its handling. Where the injection of a saline solution is contemplated, a multiple tube probe is required, thereby necessitating a larger probe than otherwise, which is undesirable. Further, the Eisenberg apparatus contemplates flushing with air, which has no significant effect on the temperature of the tissue which has received the laser radiation. SUMMARY OF THE INVENTION There are provided a method and apparatus for phaco-emulsification of the lens of an eye. A hollow probe is connected to an excimer laser of short wavelength. The probe is also connected to apparatus for introducing and removing precise amounts of liquid, i.e. saline solution, into the lens through the probe, sufficient to form a small bubble of that liquid at the distal end of the probe. This apparatus preferably takes the form of an infusion and an extraction liquid pumping and metering system, each including a solenoid operated piston and solenoid operated inlet and outlet valves. The sequencing of the pistons and valves and the laser is controlled by or through a computer for effecting the steps of infusing liquid, firing the laser, and extracting the liquid. The sequence may be varied. For example, after infusion of the liquid to form the bubble, the laser is fired and the fluid is removed, or the sequence may include plural flushing steps between each or selected radiation steps, or in some instances, the instrument may be used without any laser radiation delivered to the site. The laser radiation is directed through the liquid in the hollow probe and through the liquid sphere or bubble at the distal end of the probe. A method of phaco-emulsification is provided by forming a small bubble or sphere of liquid within and engaging human tissue, such as a lens, applying excimer ablative laser radiation to the tissue through the bubble or sphere, extracting the bubble or sphere, together with liquified lens tissue mixed with the liquid, the amounts of liquid introduced into and removed from the tissue being precisely controlled. The washing of a site is achieved by multiple steps of liquid infusion and extraction, with or without the application of laser energy to the site between successive infusion and extraction steps. Emulsification of tissue is effected by applying ablative laser radiation to the tissue, through a body of liquid adjacent to and engaging at least a portion of the tissue, followed by extraction of the ablated tissue and liquid, and including repetition of the steps. Among the objects of the present invention are the provision of a thin, easily manipulable hollow probe for phaco-emulsification by the application of laser radiation, including provision for infusion and extraction of fluid and the application of laser energy to tissue through the same probe passage. Another object of the invention is the provision of a probe and attendant method in which laser energy is delivered through a liquid bubble or sphere which engages tissue to achieve superior coupling and sharp focussing. A still further object is to provide phaco-emulsification apparatus in which excimer laser pulse energy is applied to human tissue, particularly lens tissue. Another object of the invention is the provision of an apparatus and method in which laser energy is applied to tissue and is of a character which will permit high absorption and localized effect. Yet another object of the invention is the provision of apparatus and method in which a precise amount of liquid is infused into a lens, and extracted from a lens, and in which there is removal of heat from the lens due to the application of laser energy by heat exchange with fluid infused into and extracted from the lens before and after the application of laser energy. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic view, with parts removed, of a liquid conduit laser surgical probe in accordance with the present invention, and related apparatus. Fig. 2 is a cross-sectional view, partly schematic, of a liquid conduit laser surgical probe and related apparatus in accordance with the present invention. Fig. 3 is a schematic view of a computer forming a part of the present invention. Fig. 4 is a view illustrating the use of the liquid conduit laser surgical probe apparatus of the present invention. Figs. 5-10 are schematic views illustrating successive steps in the use of the liquid conduit laser surgical probe apparatus of the present invention, and the related method. DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings, wherein like or corresponding reference numerals are used to designate like or corresponding parts throughout the several views, there is shown in Fig. 1 a liquid conduit laser surgical apparatus 10 in accordance with the present invention which includes a handpiece 12 connected in known manner to an articulated arm system 14, the arm system 14 being operatively connected to a laser 16. The articulated arm system 14 may be of a known type, or of an advanced type which is the subject of a separate patent application thereon (Attorney Docket No. Y-0337). Laser 16 is an excimer laser such as an ArF, which generates ablative laser energy. The wavelength of the generated laser beam is short, being 193 nm. The laser beam is delivered in pulses, in known manner, through the articulated arm system 14 to the handpiece 12, for delivery to the operative site. The handpiece 12 includes a hollow probe 18, the distal end of which, as shown, enters the eye E and penetrates into the tissue of the lens. In Fig. 2 there is shown, partly schematically and partly in section, the probe 18 of the handpiece 12. Probe 18 will be seen to be a single hollow tube, and is typically a metal channel of the characteristic wall thickness and diameter of a No. 21 or No. 24 syringe needle. The inside surface of the hollow probe 18 is polished or otherwise made reflective. At the proximal end of the hollow probe 18 are an optical coupler apparatus generally designated 20, and a chamber 44. Coupler apparatus 20 includes a focussing lens 22 for focussing the laser beam B, directing it to a collimating lens 24 and from thence the beam B passes through an optical window wedge 26 which serves to change the axis of the beam so that it will strike at a glancing angle the interior surface of the hollow probe 18 and be reflected to the distal end. An infusion pumping and metering apparatus 30 is provided, which includes a solenoid operated piston 32 within a cylinder 34, a T-shaped conduit 36 being connected to the single inlet port of cylinder 34. Solenoid operated valves 38 and 40 control the entry into and discharge from the cylinder 34 of a saline solution or other suitable liquid. The inlet solenoid valve 38 is also connected to inlet conduit 42 which is connected to a source (not shown) of saline solution. The outlet of solenoid valve 40 is connected to an arm of the chamber 44 at the proximal end of the hollow probe 18. An extraction pumping and metering apparatus 50 is provided, being generally similar to the apparatus 30. It will be seen to include a solenoid operated piston 52 within a cylinder 54, the inlet to cylinder 54 being connected to a T-shaped conduit 56 having an inlet solenoid operated valve 58 and an outlet solenoid operated valve 60, inlet solenoid operated valve 58 being connected to the arm of the chamber 44 and the outlet solenoid operated valve 60 being connected to an extraction conduit 62. If desired, an aspirator (not shown) may be connected to the conduit 62. A timing and actuating signal generator 66 is shown in Fig. 3, and is connected in known manner to cause firing of the laser 16, as well as the supplying of signals to the solenoids of the pistons 32 and 52 and to the solenoid operated valves 38, 40, 58 and 60. In Fig. 4, there is shown the probe 18 entering into the tissue forming the lens L of an eye E, in known fashion. There is shown also a sphere S, greatly enlarged for purposes of clarity, formed of liquid which has been introduced into the lens L through the hollow probe 18. Referring now to Fig. 5, there is shown a first step in the operation of the phaco-emulsification apparatus 10, after the probe 12 has been inserted into the lens L. Although not illustrated in Fig. 5 for purposes of clarity, before insertion of probe 18 into the lens L, the chamber 44, probe 18 and the extraction pumping and metering apparatus 50 will have been filled with liquid. Signal generator 66, upon actuation, will cause the inlet valve 38 to be opened, with the other three valves closed: the solenoid for the piston 32 is energized, causing piston 32 to rise and to thereby draw in a predetermined, precise amount of saline solution. In the next step, as shown in Fig. 6, inlet valve 38 is closed and outlet valve 40 is opened, thereby communicating the cylinder 34 with chamber 44 and probe 18, the piston 32 being caused to descend to pump a precise measured volume of saline solution into the chamber 44 and probe 18. By careful control of the volumes of the spaces involved, including cylinder 34, conduit 36, chamber 44 and probe 18, a sphere S of liquid saline solution is caused to form at and about the distal end of the hollow probe 18. Sphere S is a liquid saline body, of generally spherical configuration, having a diameter of .5 mm, for example. Optionally, as shown in Fig. 7, at the end of the downstroke of the piston 32, the valves 58 and 60 may be momentarily opened, to permit a very small quantity of fluid to wash across the surface of the optical window wedge 26 to clear it of any debris which may be in front of it from previous operational steps. The chamber 44 will be seen to have two arms, which extend along an axis which is transverse to the axis of the window 26 and the probe 18. The infusion pumping and metering apparatus 30 and the extraction pumping and metering apparatus 50 are consequently positioned, by the construction of the chamber 44, to cause liquid to flow across the window 26 so as to remove ablated tissue from the optical path adjacent window 26. If the washing step illustrated in Fig. 7 is utilized, it will be understood that the valves 58 and 60 will be opened only momentarily, so that only an extremely small quantity of liquid will pass through them. In Fig. 8, there is shown the laser firing step, in which all valves 38, 40, 58 and 60 are closed, and the pistons 32 and 52 are at rest. The pulse of laser, indicated by the beam B, passes through the focussing lens 22, collimating lens 24 and the optical window wedge 26, striking the interior surface of the hollow probe 18, passing through the saline solution within the chamber 44 and probe 18, and through the liquid sphere S at the distal end of the probe 18 within the lens L. The laser energy will pass to the surrounding lens tissue through the effectively coupled and sharply focussed interface between the liquid forming the sphere S and the lens L. There will thereby result a very high absorption of the laser energy in the target tissue within the capsule of the lens L. Since the excimer laser 16 generates only short wavelength radiation, localization of the effect of the radiation within the lens tissue is achieved, thereby avoiding harm to other tissue, such as the cornea and retina. Fig. 9 illustrates the extraction step, in which the valves 38 and 40 are closed, the inlet valve 58 of the extraction pumping and metering apparatus 50 being open and outlet valve 60 remaining closed, and the piston 52 being raised to extract a predetermined quantity of liquid. This withdraws from the eye E the liquid forming the sphere S, together with any portions of the tissue which have entered into or mixed with the liquid forming sphere S, so that it is extracted with that liquid. Fig. 10 shows the discharge step in which the valves 38 and 40 are closed, as well as the valve 58, the valve 60 now being open, and the piston 52 descending to eject the liquid from within cylinder 54 through the discharge conduit 62. Various changes in the sequencing of the steps above described may be made. For example, there may be a series of infusion and extraction steps without an intermediate radiation step. Alternatively, the laser radiation step may take place following each infusion step. Further, in some instances, the probe 18, together with the infusion pumping and metering system 30 and the extraction pumping and metering system 50 may be used without laser energy application, as for irrigation washing of specific sites. The volumes of the hollow probe 18, chamber 44, and the pumping and metering systems 30 and 50 are very small, so that the total volume of liquid displaced in a single cycle is in the order of 0.008 cc for modest sizes of probes in the order above indicated. Because of the exceptionally small volume, there are negligible pressure fluctuations in the lens capsule, and this, together with the small dimensions of the probe 18, allow cataract surgery to be performed within the lens capsule with the least perturbation. In the use of the apparatus herein disclosed, the energy from the laser will traverse the liquid in the hollow probe 18 and the bubble or sphere S, acting through the smooth interface of sphere S with the surrounding tissue to deliver the short wavelength radiation to that tissue, to ablate it. There is emulsification or liquification, as a result, of the tissue which is immediately adjacent to the sphere. The distal end of the probe, therefore, will be located within the capsule to engage the tissue and cause emulsification or liquification, through the application of laser energy to different portions of the lens tissue until it has all been emulsified or liquified, and extracted. While the mass of liquid at the distal end of the probe 18 is stated to be a sphere, it may not be spherical, but may be of other shapes: it is a contiguous mass bounded by tissue, so that "sphere" is used herein in this context. The withdrawal of saline solution and liquified lens tissue is effected by withdrawing only a small part of the lens tissue at a time. The volume previously occupied by the lens tissue is replaced by saline solution which is left in the lens capsule during the procedure. There has been provided a method and apparatus for achieving phaco-emulsification by application of laser energy through a generally spherical or contiguous mass of saline solution or other liquid which is in engagement with the lens tissue. The apparatus herein described is highly effective, being relatively thin, and using a single passage within a hollow probe to conduct laser energy and to infuse and extract liquid into the lens capsule. Through use of an excimer ablative laser as above described, there is high absorption of the laser energy in the target tissue, thereby minimizing risk of harmful radiation delivery to other tissue, such as cornea and retina. This is due to the short wavelength of the laser radiation, resulting in a localized effect of the radiation on the lens tissue. Further, there is no air introduced into the capsule with the method and apparatus of the present invention, and as will be appreciated, the exchange of liquid, by infusion and extraction, serves to remove heat from tissues which have been subjected to radiation, thereby avoiding tissue damage. It will be obvious to one skilled in the art that various changes may be made without departure from the spirit of the invention, and therefore the invention is not limited to that shown in the drawings, and described in the specification, but only as indicated in the appended claims.

Claims: WHAT IS CLAIMED IS: 1. Apparatus for emulsification of tissue such as cataractous lens tissue and extraction thereof comprising: (a) a hollow probe, (b) means for generating ablative laser energy, (c) means for delivering laser energy from said generating means into said hollow probe, (d) means for infusing a measured quantity of liquid into said hollow probe, and (e) means for extracting a measured quantity of liquid from said hollow probe. 2. The apparatus of claim 1, wherein said hollow probe is of generally cylindrical configuration having reflective internal walls and said delivery means comprises means for delivering laser energy non-axially into said probe. 3. The apparatus of claim 1, wherein said means for generating ablative laser energy comprises an excimer laser. 4. The apparatus of claim 3, wherein said generating means is a laser for generating laser energy of a wavelength of approximately 193 ran. 5. The apparatus of claim 1, wherein said means for delivering laser energy comprises a focussing lens. 6. The apparatus of claim 5, wherein said means for delivering laser energy further comprises a collimating lens positioned to receive laser energy from said focussing lens. 7. The apparatus of claim 6, wherein said means for delivering laser energy further comprises an optical wedge. 8. The apparatus of claim 1, wherein said means for delivering laser energy further comprises an optical wedge. 9. The apparatus of claim 1, wherein said means for infusing liquid comprises means for introducing an amount of liquid sufficient to form a sphere of said liquid at the distal end of said probe. 10. The apparatus of claim 9, wherein said means for delivering laser energy comprises means for delivering said laser energy to said probe when there is present said sphere of liquid at the distal end of said probe. 11. The apparatus of claim 1, wherein said means for infusing liquid comprises an inlet conduit, a metering pump fluid connected to said inlet conduit, and valve means for controlling fluid flow to and from said metering pump. 12. The apparatus of claim 11, said apparatus further comprising means for automatically operating said valve means. 13. The phaco-emulsification apparatus of claim 12, wherein said last mentioned means comprises a computer. 14. The apparatus of claim 1, wherein said means for extracting a measured quantity of liquid comprises a discharge conduit, a metering pump fluid connected to said outlet conduit, and valve means for controlling fluid flow to and from said metering pump. 15. The apparatus of claim 14, said apparatus further comprising means for automatically operating said first and second valve means. 16. The apparatus of claim 15, wherein said last mentioned means comprises a computer. 17. The apparatus of claim 1, wherein said means for infusing liquid and said means for extracting liquid each comprises a metering pump and valve means for controlling fluid flow to and from said metering pump, said apparatus further comprising means for automatically operating said valves and said pumps. 18. The apparatus of claim 17, wherein said last mentioned means comprises a computer. 19. The apparatus of claim 1, wherein said means for delivering laser energy comprises a window through which said laser energy is introduced into said hollow probe, said infusion and extraction means positioned to cause liquid flow across said window from said infusion means to said extraction means, and wherein said operating means causes said infusion means to introduce a quantity of fluid sufficient to form a sphere of fluid at the distal end of said probe, and thereafter causes fluid to flow from said infusion means to said extraction means. 20. The apparatus of claim 19, the distal end of said probe is connected to a chamber having an inlet and an outlet positioned on a common axis, and the axis of said window is transversely of said axis. 21. Apparatus for washing a site within a body comprising: (a) a hollow probe, (b) means for introducing a measured quantity of liquid into said body through said probe, and (c) means for withdrawing a measured quantity of liquid from said body through said hollow probe. 22. The apparatus of claim 21, wherein at least one of said means comprises a metering pump and valve means for controlling fluid flow to and from said metering pump. 23. A method for the emulsification and extraction of tissue comprising: (a) engaging tissue with a mass of liquid, (b) emulsifying tissue by applying ablative laser radiation thereto, through said liquid, and (c) extracting liquid with emulsified tissue therein. 24. The method for the emulsification and extraction of tissue of claim 23, and further comprising: providing an excimer laser for generating the applied ablative laser radiation. 25. The method for the emulsification and extraction of tissue of claim 23, wherein said placing is of a generally spherical mass of liquid. 26. The method for the emulsification and extraction of tissue of claim 25, wherein said extraction is by removing a mixture of said liquid and emulsified tissue. 27. The method for the emulsification and extraction of tissue of claim 26, and further comprising, after said extraction of said mixture of liquid and emulsified tissue, infusing additional liquid to form a further generally spherical mass of liquid engaging said tissue, and thereafter applying ablative laser radiation to tissue through said second mass of liquid. 28. The method for the emulsification and extraction of tissue of claim 27, and further comprising, after an application of ablative laser radiation at one site, and the extraction of liquid and emulsified tissue, an additional generally spherical mass of liquid is placed at a different site prior to a further application of ablative laser radiation to tissue, whereby tissue at a different site is emulsified and extracted. 29. A method of washing or irrigating a site within a human body comprising: (a) infusing a measured quantity of liquid into said body, and (b) extracting said measured quantity of liquid, together with any material mixed therewith, from said body. 30. The method of claim 29, wherein the infusion is of a quantity which forms a generally spherical mass. 31. The method of claim 29, wherein the infusion is of a measured amount which forms a substantially contiguous mass bounded by tissue within said body.

Inventors: POIRIER ROBERT H, TABOADA JOHN, POIRIER, ROBERT, H., TABOADA, JOHN
Applicants: REFRACTIVE LASER RES & DEV, REFRACTIVE LASER RESEARCH & DEVELOPMENT PROGRAM, L
Application year: 1989
Main classification: A61F9
IPC codes: A61B18, A61F9, A61M1