CA1237482A

CA1237482A - Catheter for effecting removal of obstructions from a biological duct

Info

Publication number: CA1237482A
Application number: CA000449331A
Authority: CA
Inventors: Frank B. Stiles
Original assignee: Individual
Current assignee: Individual
Priority date: 1984-03-09
Filing date: 1984-03-09
Publication date: 1988-05-31
Also published as: US4692139A

Abstract

ABSTRACT

A catheter for insertion into a biological duct such as an artery, comprised of a flexible aspiration tube disposed within a delivery sleeve and connected at one end to a source of vacuum for providing suction within the duct in the vicinity of a biological obstruction, such as a blood clot. An injection tube extends through the aspiration tube for injecting medication into the duct, and an ultrasonic energy source also extends through the aspiration tube for transmitting ultrasound in the vicinity of the obstruction. The transmitted ultrasound and injected medication cooperate to emulsify and fragment the obstruction, and the fragmented obstruction is removed through the aspiration tube in response to suction being applied thereto. The catheter is compact and easily manipulable, providing substantial surgical accuracy.

Description

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01 This invention relates in general to 02 surgical instruments, and in particular to a 03 catheter for insertion into a biological duct in 04 order to effect removal of obstructions therefrom.
05 Prior art surgical devices are well 06 known for disintegrating obstructions such as stones 07 or concretions from the urinary track as well as 08 plaque and sclerotic clots in other human ducts such 09 as arteries. Canadian patent number 866,946 entitled I~STRUME~T FOR CRUSHING STONES I~ THE
11 URINARY BLADDER, issued March 23, 1971 to Balaev et 12 al teaches an electrical device for discharging 13 electrical pulses in a gap between a pair of 14 electrodes surrounding an obstruction. The impact of the electrical discharge causes the obstruction 16 to disintegrate. However, no means are taught for 17 removing the fragmented obstruction. Also, it has 18 been found that such electrical discharges can burn 19 or otherwise damage surrounding biotissue.
Likewise, Canadian patent number 21 1,078,925 entitled CALCULI DISI~TEGRATING APPRATUS, 22 issued June 3, 1980 to Calculus Instruments Limited, 23 teaches a surgical device having positive and 24 negative electrodes for effecting an electrical discharge in conjunction with application of a 26 liquid, in order to disintegrate an obstruction via 27 hydro-electric action. l'he Calculus Instruments 28 device utilizes a harp distender for distending the 29 duct walls to reduce burning and shock damage to the skin as a result of the electric discharge.
31 Notwithstanding utilization of the harp distender, 32 it has been found that prior art electric discharge 33 devices sucll as those disclosed in the Balaev et al 34 and Calculus Instruments patents, produce considerable trauma in the human body.
36 Surgical instruments are also well known 37 for aspirating speci~ic regions of a body cavity in 7~

01 order to remove residual matter. One such device is 02 described in Canadian patent number 1,006,231 issued 03 March 1, 1977 to Durden, which teaches the use of a 04 suction tube in a cauterizing instrument.
05 ~dvances in the surgical arts have led 06 to the use of ultrasound for fragmenting 07 obstructions, which has been found to be 08 substantially less traumatic to the human body than 09 prior art electrical discharge apparatus. In order to enhance the obstruction disintegration properties 11 of ultrasound, it has been contemplated that 12 medication, such as an enzyme, may be simultaneously 13 injected in the vicinity of the obstruction. A
14 device utilizing ultrasound is described in Canadian patent 1,092,657 entitled DEVICE ~ND METHOD FOR
16 APPLYING PRECISE IRRIG~TION, ASPIRATION, MED~CATION, 18 SURGER~ AND TREATMENT issued December 30, 1980 to 19 Fibra-Sonics, Inc. The Fibra-Sonics device utili~es two separate ducts disposed in two separate needles 21 for providing irrigation and aspiration in 22 conjunction with ultrasound. According to the 23 Fibra-Sonics device an irrigation needle is inserted 24 directly into the human body by applying ultrasound to the needle in order to make an incision in the 26 immediate vicinity of the obstruction. The forceul 27 injection of dissolvents by means of the inserted 28 needle in conjunction with bursts of ultrasound 29 transmitted through the needle results in rapid emulsification of the obstruction. A separate 31 aspiration needle is also inserted into the body in 32 the vicinity of the obstruction, via a separate 33 incision, in order to remove the fragmented 34 obstruction and any residual medication. In the event the area surrounding the obstruction is not 36 adequately aspirated, fragments and residual 37 medication can migrate through the circulatory ~23~

01 system which may lead ko a critical situation in the 02 event the medication is an enzyme for dissolving 03 blood clots, since the enzyme would damage heart 04 tissue if not immediately removed. However, since 05 two incisions are made the fragments and residual 06 medication are not confined to within the biological 07 duct (such as an artery) but may inadvertently spill 08 out from the duct through one or both of the 09 incisions. Thus, great care must be taken when utilizing the Fibra-Sonics device to ensure adequate 11 aspiration. Thus, while it is known to use 12 aspiration in surgery (as taught by either Durden or 13 Fibra-Sonics) and irrigation with ultrasound, to 14 fragment or dissolve obstructions (as taught by Fibra-Sonics) it has not hitherto been known to 16 simultaneously incorporate irrigation, aspiration 17 and ultrasound in a single unitary surgical 18 instrument. As discussed in the Fibra-Sonics 19 patent, it was believed that incorporation of all three functions in a single instrument, requiring at 21 least two adjacent ducts (one for aspiration and one 22 for medication), would result in severe trauma, 23 since a large incision would be required.
24 According to the preseNt invention, a device is provided for integrating the functions of 26 aspiration, irrigation and ultrasound application 27 within a single catheter, for insertion into a 28 biological duct via a single incision remote from 29 the vicinity of the obstruction and moved in~o 3~ position within the duct. Thus, irrigation, 31 ultrasound generation and aspiration occur within 32 the confines of the biological duct and are 33 localized in the vicinity of the obstruction.
3~ Hence, fragments and residual medication are immediately and easily removed without risk of 36 spreading to o~her parts of the body through the ~3~

01 circulatory system. Thus, the present inven-tion 02 overcomes the disadvantages of Calculus Instruments 03 and Balaev et al which required traumatic electro 04 shock treatment to disintegrate obstruct.ions, yet 05 also overcomes the disadvantage of Fibra-Sonics or 06 Durden which require incisions to be made in the 07 human body.
08 In general, the invention is a catheter 09 for effecting removal of obstructions from a biological duct, comprising a flex.ible aspiration 11 for insertion into the duct such that a first end 12 thereof is disposed in the vicinity of the 13 obstruction and on opposite end thereof is 14 connectable to a source of vacuum for providing suction within the duct at the first end in the 16 vicinity of the obstruction, an injection tube 17 disposed within the aspiration tube for injecting 18 medication into the duct in the vicinity of the 19 obstruction, and an ultrasonic energy source ~or transmitting ultrasound through the aspiration tube 21 in the vicinity of the obstruction. The ultrasound 22 and medication cooperate to emulsify and fragment 23 the obstruction, and the emulsified ar~d fragmented 24 obstruction is removPd from the duct through the aspiration tube in response to suction being 26 provided.
27 The invention is also a method of 28 fragmenting and removing obstructions from a 29 biological duct, comprising the steps of inserting a catheter into the duct, deploying an aspiration tube 31 housed within the catheter and including a 32 medication tube and ultrasonic energy source, to a 33 position externally of an open end of the catheter 3~ in the vicinity of the obstruction, and injecting medication and transmitting ultrasonic energy via 36 the medication tube and ultrasonic energy source 37 respectively in the vicinity of the obstruction for 01 emulsifying and fragmenting the obstruction, and 02 simultaneously vacuuming the vicinity to remove 03 emulsified fragmenks of the obstruction and residual 04 medication via the aspiration tube.
05 A better understanding of the present 06 invention will be obtained with re~erence to the 07 detailed description below in conjunction with the 08 following drawings, in which:
09 Figure 1 is a longitudinal cross sectional view of a catheter according to the 11 present invention, taken along the line 1-1 shown in 12 Figure 2, 13 Figure 2 is an end view of the catheter 14 according to the present invention, Figure 3 is a longitudinal cross 16 sectional view of the catheter in a deployed 17 position, taken along the line 1-1 in Figure 2, and 18 Figures 4A and 4B are longitudinal cross 19 sectional views of apparatus for coupling an opposite end of the catheter to a source of vacuum.
21 With reference to Figure 1 a catheter is 22 shown comprised of a flexible delivery sleeve 1 23 having a threaded inner wall 2. Disposed within the 24 delivery sleeve is an aspiration tube 3 having a fine gauge male thread on an outer wall thereof, 26 matching the fine gauge female -thread 2.
27 By turning the aspiration tube 3 28 clockwise within the delivery sleeve 1, the 29 aspiration tube 3 is caused to move towards an open end of the delivery sleeve 1, due to the action of 31 the cooperating threads. An inner blocking ring 4 32 is located at the open end of the delivery sleeve 1 33 for limiting the movement of the aspiration tube 3 34 to an optimum position at the open end of the delivery sleeve.
36 Mounted on a remote end of aspiration 37 tube 3 is a folded soft springy rubber shield 5.

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01 The shield 5 is shown in a collapsed retracted 02 position within the flexible deliver~v sleeve 1. An 03 ultrasound probe 6 and medication injection tube 7 04 are disposed within the aspiration tube 3 and have 05 remote ends thereof located at the open end of 06 delivery sleeve 1.
07 Turning to Figure 2, the position of 08 medication injection tube 7 and ultrasound probe 6 09 disposed within aspiration tube 3, is shown in greater detail.
11 In Figure 3, the aspiration tube 3 is 12 shown in a deployed position, having been turned 13 cloc~wise within delivery sleeve 1 to a position in 14 abutment with blocking ring 4. In this position, medication injection tube 7 and ultrasound probe 6 16 extend beyond the open end of the delivery sleeve 1, 17 and shield 5 is shown in an expanded deployed 18 position. The shield 5 opens and closes between the 19 deployed and retracted positions with an action similar to that of opening and closing an umbrella.
21 Referring to Figure 4, a base end of the 22 aspiration tube 3 extends from the base end of 23 delivery sleeve 1, and has fine gauge male threads

2~ disposed on an outer wall thereof for coupling with fine gauge female threads disposed within an inner 26 wall of a sealed coupler 9 for coupling the 27 aspiration tube 3 to a source of vacuum, tnot shown) 28 such as a well known variable range AC/DC powered 29 vacuum pump including rate controls, foot pedal action controls and a sterile container for 31 receiving the removed fragments in order to 32 facilitate biopsy analysis.
33 A sealed junction 11 projects from the 34 outer wall of aspiration tube 3, and the ultrasonic probe 6 and medication injection tube 7 extend 36 therethrough for connection to an external 37 ultrasound energy source and a source of medication, ~23~

01 respectively.
02 The source of medication is preferably 03 an injector syringe, automatic AC/DC peristaltic 0~ pump or other device for propelling medication, such 05 as an enzyme, through the injection tube 7 at a 06 predetermined rate and pressure, which preferably 07 can be either steady or pulsating.
08 The ultrasonic energy source is 09 preferably a well known adjustable, multi-high range frequency AC/DC resonator or oscillator.
11 The delivery sleeve 1, aspiration tube 3 12 and medication injection tube 7 are preferably 13 fabricated from high quality surgical plastic.
14 In order to emulsify and fragment an obstruction such as a blood clot blocking the 16 coronary artery or other artery chambers of the 17 heart, the delivery sleeve 1 is preferably inserted 18 into an appropriate leg artery according to well 19 known surgical techniques, and is fed through the artery to a position within the coronary artery or 21 artery chamber in close proximity to the 22 obstruction~
23 With the delivery sleeve in place, and 24 the base end thereof projecting outwardly from the leg artery, the aspiration tube 3 is turned 26 clockwise at the base end. In response, the 27 aspiration tube 3 moves to the deployed position as 28 illustrated by Figure 3, wherein the blocking ring 4 29 prevents the aspiration tube 3 from extending beyond the end of the delivery sleeve 1. The rubber shield 31 5 expands and the ultrasonic probe 6 and medication 32 injection tube 7 extend from the end of the sleeve 1 33 so as to be preferably in close proximity to the 34 obstruction.
The aspiration tube 3 is then coupled at 36 the base end via coupling 9 by rotating the coupling 37 such that the mutual threads of the coupling 9 and ~3~

01 aspiration tube 3 cooperate to draw the tube into 02 air-tight engagement with the source of vacuum.
03 As discussed above, the ultrasonic probe 04 6 extending outwardly from junction 11, is connected 05 to the source of ultrasonic energy, which preerably 06 has a foot control pedal for controlling the 07 frequency and intensity of the energy, and 08 preferably generates signals having frequencies of 09 at least 60 kilohertz.
The medication injection tube 7 11 extending from junction 11 is then connected to the 12 source of medication such as the aforementioned 13 automatic adjustable injection pump. As discussed 14 above, the pump is preferably capable o accommodating multiple rate Eixed, steady or 16 pulsating action for propelling controlled volumes 17 of medication such as enzymes in an oxygen enriched 18 saline solution, or otherwise, down the tube 7 at a 19 predetermined rate of fixed, steady or pulsating volume, concentration, speed and pressure.
21 According to a preferred use of the 22 present invention for emulsifying blood clots, an 23 enzyme such as streptokinase, t-PA, etc., with or 24 without a blood plasma or saline carrier, is in]ected into the coronary artery for causing the 26 blood clot to emulisfy and fragment.
27 The accompanying ultrasonic energy 28 transmitted via ultrasound probe 6 serves to 29 accelerate the emulsifying and fragmenting action caused by application of -the enzyme, and with the 31 source of vacuum set a-t a predetermined rate above 32 normal blood flow pressure, the fragments and 33 residual enzymes are collected and removed via 34 aspiration tube 3. The shield 5 serves to direct the movement o the ragments and r~sidual enzymes 36 into the aspiration tube 3. Clot dissolving enzymes 37 can cause damage to heart tissues, and it has been ~, 01 found that by aspirating the area surrounding the 02 fragmented clot so as to remove the residual enzymes 03 and prevent them from passing through the general 04 vascular blood stream of the patient, such damage is 05 substantial]y eliminated. Thus, higher 06 concentration enzymes and other medication may be 07 used in the present invention than in prior art 08 devices since the highly efficient aspiration 09 process ensures that the residual medication does not spread to other parts of the body.
11 Once the clot has been removed, the 12 ultrasonic probe 6, injection tube 7 and aspiration 13 tube 3 are disconnected at the base end and the 14 aspiration tube 3 is turned counter-clockwise so as to move the shield 5, probe 6 and tube 7 into a 16 retracted position within the delivery sleeve 1, as 17 illustrated by Figure 1. The delivery sleeve 1 is 18 then withdrawn from the patient's body in a straight 19 forward well known manner.
According to the present invention, it 21 has been found that a blood clot will emulsify, 22 fragment and be removed in approximately no more 23 than two and one-half minutes. Because speed is of 24 the essence when removing a blood clot or in the event of a heart attack, the present invention has 26 been found to be a unique improvement over prior art 27 devices. Also, by removing blood clot fragments by 28 aspiration, the fragments are prevented from 29 travelling through the patient's circulatory system to the lungs or brain which otherwise could cause 31 brain damage or stroke, etc. Further, as a result 32 of integrating the aspiration tube, medica~ion 33 irrigation tube, ultrasound probe and shield in a 34 single catheter, stronger and more effective enzymes may be applied in the vicinity of an obstruction 36 which, in the absence of efficient aspiration, would 37 overthin a patient's blood which can be dangerous in 38 _ 9 _ . .

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01 the event of imminent surgery. By fragmen-ting and 02 removing obstructions in such a rapid and eEfective 03 manner oxygen is rapidly restored to the heart 04 muscles and related tissues, thereby preventing 05 irreversible heart damage, etc.
06 A person skilled in the art 07 understanding the present invention may conceive of 08 further embodiments or variations using the 09 principles disclosed herein. For instance, by slightly modifying the dimensions of the present 11 device, it can be used to remove cataracts from the 12 eyes, bladder stones from -~he urinary system, and 13 other obstructions from various internal biological 14 ducts without requiring major surgery. ~lso, while ultrasonic probe 6 has been shown in the drawings 16 (Figure 2) as being of circular cross section, it 17 can alternatively be made of square cross section.
18 All these and other modifications or 19 variations are considered to be within the sphere and scope of this invention as defined in the claims 21 appended hereto.

Claims

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A catheter for effecting removal of obstructions from a biological duct, comprising a flexible aspiration tube for insertion into said duct such that a first end thereof is disposed in the vicinity of said obstruction and an opposite end thereof is connectable to a source of vacuum for providing suction within said duct at said first end in the vicinity of said obstruction, an injection tube disposed within said aspiration tube for injecting medication into said duct in the vicinity of said obstruction, and an ultrasonic energy source for transmitting ultrasound through said aspiration tube to the vicinity of said obstruction, whereby said ultrasonic energy and medication cooperate to emulsify and fragment said obstruction and the emulsified and fragmented obstruction is removed from said duct through the aspiration tube in response to suction being provided by said source of vacuum.

20 A catheter as defined in claim 1, further including a flexible delivery sleeve enveloping said aspiration tube and coupled thereto at said first end by mutual threading, said aspiration tube being movable between extended and retracted positions relative to said sleeve by rotation therein.

3. A catheter as defined in claim 2, further including a collapsible shield connected to said first end of the aspiration tube, said shield being movable between a collapsed position within said delivery tube and a deployed position externally of said delivery tube in response to said aspiration tube being moved between said retracted and extended positions respectively, whereby in said deployed position the shield directs removal of said fragmented matter from said vicinity into the aspiration tube.

4. A catheter as defined in claim 2 or 3 further including a blocking ring disposed on an inner surface of said delivery sleeve at said first end, for limiting movement of said aspiration tube between said retracted position and a predetermined optimum extended position.

5. A catheter as defined in claim 3 wherein said shield is fabricated from flexible rubber.

6. A catheter as defined in claim 1, 2 or 3 wherein said ultrasonic energy source is comprised of a variable frequency ultrasonic oscillator connected at said opposite end of the aspiration tube to an ultrasonic probe extending therethrough and terminating at said first end.

7. A catheter as defined in claim 1, 2 or 3 wherein said ultrasonic energy source is comprised of a variable frequency ultrasonic oscillator connected at said opposite end of the aspiration tube to an ultrasonic probe having substantially square cross section and extending through said aspiration tube and terminating at said first end.

8. A catheter as defined in claim 1, 2 or 3 wherein said source of vacuum is a vacuum pump.

9. A catheter as defined in claim 1, 2 or 3 wherein said source of vacuum is a vacuum pump and said aspiration tube is connected at said opposite end thereto via mutual threading disposed within an air-tight sealed coupler.

10. A catheter as defined in claim 1, 2 or 3 wherein said injection tube is connected at said opposite end to an injector syringe.

11. A catheter as defined in claim 1, 2 or 3 wherein said injection tube is connected at said opposite end to an automatic AC/DC pump.

12. A catheter as defined in claim 1, 2 or 3 wherein said injection tube is connected at said opposite end to means for propelling medication therethrough at one of either a steady speed and pressure or a pulsating speed and pressure.

13. A catheter as defined in claim 2 or 3 wherein said delivery sleeve and aspiration tube are fabricated from surgical plastic.

14. A catheter as defined in claim 1, 2 or 3 wherein said source of vacuum is a variable range AC/DC powered vacuum pump including rate controls, foot pedal action controls and a sterile container for receiving said removed fragments in order to facilitate biopsy analysis.

15. A catheter as defined in claim 1, 2 or 3 wherein said ultrasonic energy source is comprised of an AC/DC powered multi-variable range frequency resonator for generating ultrasonic frequency signals of at least 60 kilohertz frequency.