KR20030036158A - Method and apparatus for thermal emulsification - Google Patents

Abstract

The present invention relates to a medical device capable of emulsifying tissue with heated fluid. The device includes an active heating element located inside an internal channel at the end of the cannula. The cannula is adapted to be inserted into tissue such as the cornea. The active heating element supplies heat to the fluid flowing through the inner channel. The heat is transferred to a fluid bolus that is periodically generated by the pump. The heated bolus is then directed onto the tissue.

Description

Thermal emulsification method and apparatus {Method and apparatus for thermal emulsification}

The development of medical treatments, commonly called phaco emulsification ("Paco") of cataracted lenses, has continued. Paco treatment generally involves making an incision in the cornea and inserting an ultrasonically guided tip that breaks the lens. The tip extends from the handpiece held by the doctor. The handpiece is paired with an irrigation line and a suction system. The washing line supplies an irrigation fluid to the chamber in front of the cornea. The suction system draws in the wash fluid and the emulsified tissue from the cornea.

Pacoemulsification with an ultrasonic tip generally requires breaking the lens into relatively large pieces before emulsifying the debris to be cleaned. Breaking the lens can be time consuming and complicate the process. It is known that lens tissue can be emulsified by heated liquid. The heated liquid must enter the cornea without burning surrounding corneal tissue, such as epithelium. Burning the capsular tissue can impair the vision of the speaker.

U. S. Patent No. 5,865, 790 discloses an apparatus capable of emulsifying the lens with a heated fluid. The device includes a cannula that can be inserted into the cornea. The cannula has internal channels that mate with the cleaning system. A passive heating element is located inside the inner channel at the end of the cannula. The passive heating element generates heat inside the fluid under an isenthalpic process. The heat generation takes place inside the anterior chamber of the cornea at a location away from the encapsulation. The heat generated by the passive heating element disclosed in the above patent No. 790 goes through a continuous process. It is desirable to provide a discontinuous process. For example, it is desirable to produce a continuous stream of heated fluid slugs facing the lens or a continuous stream of heated and unheated fluid slugs.

The amount of heat generated by the passive device is a function of the pressure drop across the device. The pressure drop is a function of the velocity of the fluid. The temperature of the wash fluid used to emulsify the tissue with the generated heat can be varied by varying the flow rate of the fluid through the cannula. Unfortunately, the flow rate change occurs upstream from the end of the cannula. The upstream flow change causes a time delay between the command change and the reaction of the system. Basically, it is desirable to change the temperature immediately. Accordingly, it is desirable to provide a hydro-emulsifier capable of producing discontinuous slugs of heated fluid and capable of rapidly changing the temperature of the heated slugs.

The present invention relates to a medical device capable of removing tissue with a heated fluid bolus.

1 is a side view showing the cannula end according to the first embodiment of the present invention.

FIG. 2 is a sectional view showing an active heating element located inside an inner channel of the cannula, taken by line 2-2 of FIG.

Figure 3 is a side view showing the cannula end according to a second embodiment of the present invention.

4 is a schematic diagram illustrating a medical system for supplying fluid and energy to each of the cannula and active heating element.

Fig. 5 is a sectional view showing a cannula having an optical heating element according to a third embodiment of the present invention.

Fig. 6 is a sectional view showing a cannula having a radio frequency heating element according to a fourth embodiment of the present invention.

7 is a sectional view showing a cannula having an ultrasonic heating element according to a fifth embodiment of the present invention.

* Description of the main parts of the drawings

10, 100, 120, 140: cannula 12, 16, 20: sleeve

14, 18: internal channel 22: cornea

26 active heating element 56 drive circuit

60: bolus generator 102: light source

122: radio frequency generator 142: ultrasonic generator

One embodiment of the invention includes a medical device capable of emulsifying tissue using a heated fluid. The device has an active heating element located inside the inner channel at the end of the cannula. The cannula is adapted to be inserted into tissue such as the cornea. The active heating element provides heat to the fluid flowing through the inner channel.

Referring to the drawings in more detail by reference numerals, Figures 1 and 2 show the cannula of the present invention. The cannula 10 ejects the heated fluid to emulsify the tissue. For example, the cannula 10 may be inserted into the cornea, and the heated fluid may emulsify a cataracteous lens.

However, explaining the use in an ophthalmic procedure, the cannula 10 can emulsify other tissues. For example, the present invention can be used in a "liposuction" process.

The cannula 10 may include a first sleeve 12 positioned inside an inner channel of the second sleeve 16. The second sleeve 16 may be located inside the internal channel 18 of the third sleeve 20. The diameter of the third sleeve 20 is approximately 1.5 mm and small enough to be inserted through the incision of the cornea 22. The sleeves 12, 16, and 20 may each be formed of a metal or plastic material that does not collapse under the pressure of the cornea. An irrigation fluid may flow through the inner channel 18 of the third sleeve 920. The washing fluid and the emulsified tissue are sucked through the inner channel 14 of the second sleeve 16.

The cleaning fluid may also flow through the inner channel 24 of the first sleeve 12. The active heating element may be located inside the internal channel 24 at the end of the sleeve 12. The heating element 26 transfers heat to the washing fluid flowing through the inner channel 24 to raise the temperature of the washing fluid. The fluid is generally heated to a temperature capable of emulsifying the tissue. By way of example, the fluid can be heated to 180 ° F.

In one embodiment, the heating element may be an electrical resistance member connected to a current source (not shown) by a pair of wires 28, 30. One wire 28 may extend through the inner channel 24. The other wire 30 extends along the outer surface 32 of the first sleeve 12 and extends through the opening 34 to the active heating element 27. However, Figure 2 illustrates one type of wire arrangement, which will be understood that the wires 28 and 30 can be routed in other ways. For example, each wire 28, 30 may extend along the outer surface 32 of the first sleeve 12. If the first sleeve 12 is formed of a metal material, the wires 28 and 30 may be coated with an insulating material. If the first sleeve 12 is formed of a dielectric material such as plastic, the wires 28, 30 are plated on the sleeve 12 by known sheet metal techniques.

The active heating element 26 changes the current into heat which is then transferred to the fluid. Since the heating element 26 is porous, the cleaning fluid can flow therethrough, where it functions as a micro heat exchanger. Positioning the heating element 26 at the end of the sleeve 12 provides a hydro-emulsifying device capable of heating the fluid downstream of the corneal tissue. This reduces the amount of heat transferred to the cornea at the incision point.

For example, the heating element 26 may be formed of sintered stainless steel UNS 316. Since the sintered steel has a porosity, it can filter out fine particles of the washing fluid. In another embodiment, the heating element 26 is made of a resistance element having no porosity smaller than the diameter of the inner sleeve 26 so that the cleaning fluid can flow through the element 26.

The cannula 10 includes an orifice 36 having an internal channel 38 and a tapered outlet 40 for producing a flow in the same direction as the heated wash fluid. The orifice 36 may concentrate the washing fluid on emulsified tissue.

The orifice 36 is separated from the heating element 26 by a space 42. The space 42 forms a volume or bolus of heated water directed by the orifice 36 to the tissue. In another embodiment, the cannula 10 is provided with a filter in the position of the heating element 26 and the heating element 26 inside the space 42, so that the cleaning fluid is the orifice 36 Allow it to be filtered and heated before flowing through it.

FIG. 3 shows another embodiment of the cannula 10 in which both the first sleeve 12 and the second sleeve 16 are located inside the inner channel 18 of the third sleeve 20. It is. The cannula 10 may also have a fiber optic cable 44 for transmitting light to illuminate the surgical site. The cannula 10 may also include a temperature sensor 46 for sensing the temperature of the cleaning fluid at the ends of the sleeves.

4 illustrates one embodiment of a medical system 50. The system 50 includes a handpiece 52 having a cannula 10 or 10 '. The handpiece 52 may be gripped by a doctor performing a surgical procedure, for example, removing a cataract. The handpiece 52 is connected to a console 54. The console 54 may include a driver circuit 56 connected to the handpiece 52 by an electrical cable 58. The drive circuit 56 may supply a current to the active heating element 26 shown in FIG. The drive circuit 56 may include a power supply device for periodically supplying a power pulse to the active heating element. By way of example, the drive circuit 56 can supply enough power to heat a 5-500 microliter cleaning fluid at 100 ° F. in one second. To achieve this result, the power supply can supply pulses that are 3-6 volts and have a current of 0.5 to 10 amps and last for 0.1 to 100 milliseconds.

The console 54 may also include a bolus generator 60 paired with an inner channel of the first sleeve by a tube 62. The generating device 60 generates a bolus or pulse of fluid flowing into the first sleeve or across the active heating element. The drive circuit 56 operates simultaneously with the bolus generator 60 so that power is supplied to the active heating element when the bolus of the fluid reaches the heating element.

The tube is preferably formed of a material that does not significantly expand when the increase in pressure is caused by the generation of the fluid bolus by the generating device 60. For example, the tube 62 may be made of polyether ether kethone (P.E.E.K) stacked with a Kevlar material or a metal material.

The bolus generator 60 may include a diaphragm pump 64 operated by the solenoid 66. The pump 64 may be in fluid communication with a reservoir 68 of flushing fluid. The solenoid 66 is actuated by a solenoid drive circuit 70. The drive circuit 70 expands and contracts the pump chamber inside the pump 64 to periodically operate and deactivate the solenoid 66. When the pump chamber expands, the washing fluid flows into the chamber through the one-way valve 72. When the pump chamber contracts, the cleaning fluid is discharged from the chamber through the one-way valve 74 and flows into the cannula 10 or 10 '. The flow of fluid from the fluid source 68 to the pump can be controlled by a pinch valve. Although solenoids are shown and described, the pump 64 may be driven by other means, such as piezoelectric transducers or magneto-strictive transducers.

The fluid source 68 may also be paired with an inner channel of the third sleeve by a tube 78 and a pinch valve 80. The inner channel of the second sleeve may be paired with a pump 82 that is linked by a tube 84. The pump 84 sucks wash fluid and emulsified tissue through the second sleeve. The drive circuit 56, solenoid drive circuit 70, and / or pump 82 allow the pedal 86 to allow the surgeon to vary the rate of inflow of fluid supplied from the cannula and / or fluid pulses per hour. Paired with

1, 2 and 4, during surgery, the surgeon inserts the cannula 10 or 10 'through a tissue such as the cornea into a cataractous lens. The washing fluid may flow through the inner channel 18 of the third sleeve 24. The bolus generating device 60 may periodically generate a fluid bolus flowing into the inner channel 24 of the first sleeve 12. The bolus is heated by the heating element 26 and directed by orifices 36 onto or into the tissue. The heated fluid bolus collides with the tissue to emulsify the tissue. Thereafter, the washing fluid and emulsified tissue are sucked through the inner channel 14 of the second sleeve 16 by the peristaltic pump 82. In one embodiment, the system 50 produces a heated bolus followed by an unheated fluid bolus. Continuous heated and unheated boluses can be repeated many times.

5 is another embodiment of a cannula 100 that includes an optical heating element. The cannula 100 includes a light source 102 paired with an optical fiber 104 extending through the inner channel 106 of the first sleeve 108. The light source 102 emits light transmitted to the orifice 110 by the fiber 104. The wavelength of the light and the material of the orifice 110 are selected to allow the orifice material to absorb light. The absorbed light heats the orifice 110. The heated heat is transferred to the fluid flowing through the opening 112 in the orifice 110. For example, the light source 102 may be made of a xenon flash lamp or a laser.

6 is another embodiment of a cannula 120 including a radio frequency heating element. The cannula 120 includes a radio frequency (RF) generator 122 connected with the coil 124. The coil 124 is positioned adjacent to the orifice 126 at the end of the sleeve 128. The generator 122 provides an alternating current to the coil 124 that generates an electric field. The orifice 126 provides a resistance to the electric field from which heat is generated. The heat is transferred to the fluid flowing through the opening 130 at the orifice 126.

7 is another embodiment of a cannula 140 including an ultrasonic heating element. The cannula 140 includes an ultrasonic generator 142 paired with a sleeve 144. The generator 142 drives the sleeve 144 by ultrasonic waves. The cannula 140 has an orifice 146 that generates an acoustic impedance that causes heat generation in the orifice 146. The heat is transferred to the fluid flowing through the opening 148 of the orifice 146. Ultrasonic movement of the sleeve 144 also helps to emulsify tissue.

The present invention described above is not limited to the above-described embodiment and the accompanying drawings, and it is common in the field of the present invention that various substitutions, modifications, and changes can be made without departing from the technical spirit of the present invention. It will be evident to those who have knowledge of.

Claims (24)

A first sleeve having an internal channel for receiving a fluid and adapted to be inserted into the tissue; And An active heating element located inside the inner channel and capable of heating the fluid Medical device that can be inserted into the tissue comprising a. The method of claim 1, The active heating element includes an electrical resistance member Medical devices. The method of claim 2, The active heating element has a porous Medical devices. The method of claim 1, With an orifice in the inner channel Medical devices. The method of claim 4, wherein The orifice is separated by a space from the active heating element. Medical devices. The method of claim 1, A second sleeve having an inner channel, wherein the first sleeve is located inside an inner channel of the second sleeve; Medical devices. The method of claim 1, Further comprising a third sleeve having an inner channel, wherein the second sleeve is located inside the inner channel of the third sleeve Medical devices. The method of claim 1, The active heating element has a light source Medical devices. The method of claim 1, The active heating element has a radio frequency generator Medical devices. The method of claim 1, The active heating element is provided with an ultrasonic generator Medical devices. A handpiece having a first sleeve having an inner channel and a cannula having an active heating element positioned inside the inner channel; A fluid subsystem for supplying fluid to the internal channel; And Drive circuit for supplying current to the active heating element Medical system comprising a. The method of claim 11, The active heating element has a porosity Medical systems. The method of claim 11, Further provided with an orifice located inside the inner channel Medical systems. The method of claim 13, The orifice is separated by the active heating element and a space Medical systems. The method of claim 11, Further comprising a second sleeve having an inner channel, wherein the first sleeve is located inside the inner channel of the second sleeve Medical systems. The method of claim 15, Further comprising a third sleeve having an inner channel, the second sleeve is located inside the inner channel of the third sleeve Medical systems. The method of claim 11, The fluid subsystem includes a bolus generating device for generating a fluid bolus flowing across the active heating element, wherein the drive circuit supplies current to the active heating element so that heat is generated in the active heating element. Generated in and delivered to the fluid bolus Medical systems. The method of claim 15, Further comprising a cleaning subassembly (subassembly) to mate with the inner channel of the third sleeve Medical systems. The method of claim 15, Further comprising a suction subassembly mating with the inner channel of the second sleeve Medical systems. The method of claim 17, And a control device coupled to the bolus generator and the drive circuit. Medical systems. The method of claim 19, The control device has a pedal Medical systems. Positioning the first sleeve adjacent to the tissue; Introducing a fluid through the sleeve; And Generating heat inside the active heating element such that heat is transferred to the fluid at the end of the first sleeve, wherein the heated fluid can emulsify the tissue Tissue emulsifying method comprising a. The method of claim 22, Washing the heated fluid and emulsified tissue further; Tissue emulsification method. The method of claim 22, Generating a fluid bolus introduced through the sleeve; Tissue emulsification method.