US3927675A

US3927675A - Device for fragmenting urinary calculus

Info

Publication number: US3927675A
Application number: US413864A
Authority: US
Inventors: Reimar Pohlman; Manfred Cichos
Original assignee: Individual
Current assignee: Individual
Priority date: 1972-11-16
Filing date: 1973-11-08
Publication date: 1975-12-23
Anticipated expiration: 1992-12-23
Also published as: DE2256127A1

Abstract

A device for the bloodless removal of urinary calculus by fragmenting the calculus by ultrasound and extracting the fragments with a catheter comprises a liquid-tight, flexible metal spiral tubular probe slidably mounted in a cystoscope. A flexible, elongate sound conductor such as a wire or a capillary tube having a rebound or impact element on its end is slidably mounted in the tubular probe. The conductor is oscillated by an ultrasonic transducer such as a piezo electric compound oscillator. The tubular probe is encased in a thin sheath and the forward end is turned in and liquid tightly joined to the rebound or impact element in such manner that enables said element to be extended out of the end of the probe, whilst in a retracted position it surrounds and protects the element. A fluid medium, such as a gas, may be introduced into the sheath. If the sound conductor is made of magneto strictive material and the tubular probe is made of copper a high frequency current may be fed to the spiral corresponding to the natural frequency of the conductor thereby obviating the necessity for providing a separate ultrasonic transducer.

Description

United States Patent [191 Pohlman et al.

[ Dec. 23, 1975 1 DEVICE FOR FRAGMENTING URINARY CALCULUS [22] Filed: Nov. 8, 1973 [21] Appl. No.: 413,864

[30] Foreign Application Priority Data Nov. 16, 1972 Germany 2256127 [52] US. CL. 128/328; 128/356 [51] Int. Cl. A6113 17/00 [58] Field of Search 128/328, 305, 24 A, 311, 128/356; 175/405- [56] References Cited UNITED STATES PATENTS 2,334,453 11/1943 Swofford 175/405 3,509,953 5/1970 Becker 175/405 3,543,757 12/1970 Balaev 128/328 3,557,793 1/1971 Ediny..... 128/328 3,673,475 6/1972 Britton 128/24 A 3,693,613 9/1972 Kelman 128/24 A 3,792,701 2/1974 Kloz 128/328 FOREIGN PATENTS OR APPLICATIONS 1,509,011 11/1966 France 128/328 Primary Examiner-Richard A. Gaudet Assistant ExaminerI-Ienry J. Recia Attorney, Agent, or FirmWolf, Greenfield & Sacks [5 7] ABSTRACT A device for the bloodless removal of urinary calculus by fragmenting the calculus by ultrasound and extracting the fragments with a catheter comprises a liquidtight, flexible metal spiral tubular probe slidably mounted in a cystoscope. A flexible, elongate sound conductor such as a wire or a capillary tube having a rebound or impact element on its end is slidably mounted in the tubular probe. The conductor is oscillated by an ultrasonic transducer such as a piezo electric compound oscillator. The tubular probe is encased in'a thin sheath and the forward end is turned in and liquid tightly joined to the rebound or impact element in such manner that enables said element to be extended out of the end of the probe, whilst in a retracted position'it surrounds and protects the element. A fluid medium, such as a gas, may be introduced into the sheath. If the sound conductor is made of magneto strictive material and the tubular probe is made of copper a high frequency current may be fed to the spiral corresponding to the natural frequency of the conductor thereby obviating the necessity for providing a separate ultrasonic transducer.

, 21 Claims, 4 Drawing Figures DEVICE FOR FRAGMENTING URINARY CALCULUS BACKGROUND OF THE INVENTION This invention relates to a device for effecting the bloodless removal of urinary calculus, particularly in the ureter, by fragmenting the calculus by ultrasound and extracting the fragments with a catheter.

Urinary calculus is the term applied to compact solid precipitations in the kidney, ureter, bladder and urethra. Urinary calculus can be removed by operation or bloodless removal can be effected by mechanical means. Chemical dissolution seldom succeeds.

For the bloodless mechanical removal of stones various methods have been developed, in which the stones are either comminuted in the respective organ (for example the bladder) and then removed, or in which the stones are simply extracted with the aid of loops (for example in the ureter or urethra). While urinary calculus in the bladder (vesical stones) can already be fragmented by ultrasound as a' matter of routine (US. patent application Ser. No. 351,140 filed Apr. 16, 1973') difficult accessibility in the ureter and the great tenderness of the wall of the ureter have hitherto made it impossible to perform the same fragmentation process on urinary stones wedged in the ureter. This problem is particularly difficult because on the one hand the particularly sensitive ureter wall immediately adjoining the stone must not be damaged, but on the other hand sufficient amounts of energy must be transmitted to enable stone-hard eoncretions to be fragmented. Furthermore the anatomical path from the urethra to the ureter stone through the bladder by way of the ostium entails numerous fairly sharp curves along which ultrasonic waves can be transmitted only with great difficulty. The self-suggesting idea of effecting the ultrasonic transmission through numerous thin wires guided parallel to one another was found impracticable because such thin wires tend to perform buckling vibrations, so that practically the entire ultrasonic power introduced is consumed in heat on the way to the stone. A single stiff wire on the other hand cannot be introduced into the sensitive ureter by way of the anatomical curves referred to and furthermore would give up its entire sonic power by radiation through the urine surrounding it on the relatively long path to the ureter stone.

SUMMARY OF THE INVENTION The present invention aims at obviating the foregoing disadvantages and to this end consists in a device for fragmenting urinary calculus, comprising a liquid-tight flexible metal spiral tubular probe slidably mounted in a cystoscope, a flexible, elongate sound conductor having a somewhat loosely coupled rebound element disposed at its end slidably mounted in said tubular probe, and means for oscillating said conductor ultrasonically.

BRIEF DESCRIPTION OF THE DRAWINGS In order that the invention may be more readily un derstood, reference is made to the accompanying drawings which illustrate diagrammatically and by way of example, one embodiment thereof and in which:

FIG. I is a general view of the device with a cystoscope;

FIG. 2 shows the spiral tubular probe which is to be inserted into the ureter;

FIG. 3 shows on a much enlarged scale details of construction of the working tip of the spiral tubular probe; and

FIG. 4 is a cross-section through the drilling prongs of the rebound element.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS The device shown in FIG. I is for the introduction and manipulation of the probe 2. The device consists of a spiral tubular probe 2 with an inner sound conductor 17 (see FIG. 2), which, in order to increase the amplitude of movement is fastened in the proximity of a movement node at the outlet of a longitudinally bored sonic transducer 3, for example a piezoelectric sonic transducer. For the purpose of further amplitude transformation the sonic transducer itself is stepped. Through these two measures relativelyshort and therefore convenient supersonic transducers can be used.

The probe 2 can be pushed through the element 1 and must always be moved in the longitudinal direction so that, for example, it can be introduced under visual supervision by way of the optical system 6 into the ostium (ureteric orifice into the bladder) and in the ureter itself can be brought up to the urinary calculus under X-ray supervision. It is also possible to take the probe under normal vision up to a cystic or urethral calculus and to crush these by means of this arrangement.

The sound conductor 17 which is connected to the transducer 3 can likewise be moved in the longitudinal direction in the interior of the probe 2 by moving the transducer. Not until the sound conductor 17 meets the rebound element 18 are impacts transmitted to the calculus. The transducer 3 and the connected sound conductor 17 are withdrawn by a eounterpressure spring 10 when the operator releases the transducer.

The ultrasonic transducer 3 is connected by way of connections 12 to a high frequency generator with automatic frequency control and amplitude limitation, so that on the one hand the transducer-probe system always vibrates at the optimum frequency and on the other hand the destruction of the probe in the unloaded condition is avoided.

To use the instrument only the stem 5 should at first be introduced through the urethra into the urinary bladder, without the instrument 1. Then theinstrumcnt 1, with the optical system 4 and 6 and with the transducer 3 but without the probe 2 and without the sound conductor 17, is fixed to the stem 5 by means of a bayonet connection 8. The probe 2 is passed through the instrument 1 and, with the assistance of the cystoseope optical system 6 and 4, introduced through the ostium into the ureter. Finally the sound conductor 17 is pushed into the probe 2 and screwed on to the transducer 3. The bladder liquid is replenished and regulated by way of a connection 9, likewise through the stem 5. Light (cold light) is supplied in the usual manner by way of light guide cable connection 7.

For anatomical reasons, stones in the ureter can be fragmented only with the aid of thin, very flexible probes. As shown in FIG. 2, the sound conductor accordingly consists of a thin wire with a maximum diameter of 1 mm. or of a capillary tube 17, which is loosely guided in a liquid-tight metal spiral tube 20. In addition to the longitudinal oscillation the sound conductor can therefore also perform bending oscillations, which are only slightly damped even when the spiral tube is sharply bent, since the metal sound conductor comes into contact only with the metal parts of the spiral tube. The spiral tube must however be liquid-tightly closed, as otherwise the oscillation will be considerably damped. The spiral tube is therefore surrounded by a thin sheath 16. The end of the spiral tube is closed by a loosely coupled rebound element 18, details of the construction of which can be seen from FIG. 3.

Here the ureter is designated 21 and the urinary calculus which is to be fragmented is designated 22. 17 is the sound conductor which is here shown as a cannula and is held loosely in the spiral tube 20. The rebound element 18 is held by means of a binding or an adhesive bonding 23 inside the sheath 16, which at the point 19 is turned over inwardly so that the rebound element can be moved in axial direction. In addition, the rebound element is encircled by the last turn 24 of the spiral 20, so that even when subjected to a heavy pull it cannot slip out of the thin sheath and, for example, remain in the ureter. On its end face the rebound element 18 has drilling prongs 25, the length of which is greater than the diameter of the probe. In the interior of the drilling prongs a cavity 26 is provided to receive the compact core of the stone.

The mode of operation of the device is as follows. During use the very flexible drilling probe 2, is first introduced without the sound conductor 17 through the urethra and the bladder into the ureter. The rebound element 18 is pushed back into the tip of the probe and cannot injure the ureter. Only when the tip of the probe has been brought up to the stone (under X-ray control) is the sound conductor 17 introduced. The sound conductor 17 pushes the rebound element 18 slightly forward, so that it comes into contact with the stone which is to be fragmented and can transmit the necessary impact forces.

The interposition of a loosely coupled rebound element provides the advantage that it is possible to obtain particularly high impact forces while at the same time the wall of the ureter cannot be burned even by direct contact with the tip of the probe over a long period of time, because the energy is converted in the loosely coupled rebound body into low frequency mechanical blows and there can be no lengthy concentrated energy flux which could lead to local burning and possibly to cavitation damage.

The rebound impact forces of the rebound element which are produced by ultrasonic waves, force the drilling prongs into the stone 22 and strip off its outer shell, which requires particularly low mechanical forces because the outer layers of a stone of this kind have been shown by experience to splinter and pulverise easily. The compact core of the stone on the other hand can be accommodated, without being destroyed, in the cavity 26 between the drilling prongs.

As a rule, particularly in the case of smaller stones, the entire process is thus completed, because the outer shell of the stones is pulverised or fragmented and the core of the stone is now enclosed in the cavity 26 and can be extracted together with the entire probe. If however the ureter should have sharp bends at the point in question, the drilling prongs 25, which were extended during the drilling operation, might possibly injure the ureter wall 21. If this danger should exist, a wire (not shown) provided at its front end with a screw thread can be inserted through the longitudinally cored transducer 3 and through the interior 27 of the cannula l7 and can easily be screwed into a thread 28 provided for this purpose on the rebound element 18 and can pull the latter back into the inverted end 19 of the protective sheath 16.

If the stone is large and in addition has sharp edges and if it should not be possible to remove its outer layers completely by the above-described drilling operation, a fluid medium (for example air) is injected into the sheath 16 before the rebound element 18 is pulled back in the above-described manner. Since the turnedin sheath is supported on the inside against the rebound element 18 or the drilling prongs 25, it thus widens the ureter in the direction in which the pull is applied. In the case of a larger stone the length of the drilling prongs 25 may be insufficient to drill completely through the stone, nevertheless the core which has entered the cavity 26 is still integral with the remainder of the stone and the latter can be pulled out together with the probe, because the sheath, which always slides ahead of it, effects the necessary widening of the ureter.

The procedure is particularly advantageous if the impact movements produced by the rebound element are further assisted by suitable pulse modulation of the high frequency generator required for operating the device. It has been found particularly advantageous to provide the pulse operation necessary for this purpose with the steepest possible transient flank. In addition, the disturbing heating which otherwise can readily occur with continuous sound waves can in this way be substantially reduced.

A particularly simple arrangement can be produced if the sound conductor 17 is made of a magnetostrietive material and the spiral tube 20 situated in the interior of the sheath 16 is made of copper. If the spiral tube is used at the same time as a current conducting coil and is fed with a frequency which corresponds to the natural frequency of the longitudinal oscillation of the magnetostrietive sound conductor 17, the latter will itself perform magnetostrietive natural oscillations and will no longer require external excitation. The ultrasonic transducer 3 (FIG. 1) can then be dispensed with. Although the ultrasonic powers which can be achieved with this latter arrangement are not so high as in the caseof external excitation, they are nevertheless sufficient in most cases when the urinary stones are small.

We claim:

1. A device for fragmenting urinary calculus in combination with a cystoscope and comprising a liquidtight flexible tubular probe means, said cystoscope having guide means for accommodating the probe means, said probe means slidably mounted in the cystoscope, a flexible, elongate sound conductor extending through the probe means from one end to the other end of the probe means, a rebound element disposed at the other end of the probe means having at least one cutting edge and loosely mounted in relationship to the conductor, said probe means including means at the other end of the probe means for slidably receiving said rebound element, and means for oscillating said sound conductor ultrasonically whereby said rebound element in response to the conductor is cyclically slidable and independently movable of the conductor to contact and fragment the urinary calculus.

2. A device as claimed in claim 1, wherein the sound conductor includes a readily flexible wire.

3. A device as claimed in claim 1, wherein the spiral tubular probe is liquid-tightly closed at its working end by the rebound body of which the end projecting out of the probe is provided with drilling prongs the length of which is greater than the diameter of the probe to be fragmented.

4. A device as claimed in claim 1, wherein the sound conductor is made of a magnetostrictive material and the spiral tubular probe is made of copper, and the spiral probe is fed with a high frequency current the frequency of which corresponds to the natural frequency of the sound conductor.

5. A device as claimed in claim 1 wherein the sound conductor includes a flexible capillary tube through which the fluid may pass.

6. A device as claimed in claim 1 including a loop of wire surrounding the middle of the rebound element, which loop is secured to the probe means and prevents the rebound element from being removed from the probe.

7. A device as claimed in claim 1 wherein said conductor is movable in the probe means independently of the rebound element whereas the rebound element is movable with the probe means.

8. A device as claimed in claim 7 wherein the rebound element and conductor are separate parts and there is an absence of any permanent connection therebetween.

9. A device as claimed in claim 1 wherein the probe means includes means for preventing the rebound element from disengaging therewith while the sound conductor is slidable in the probe means.

10. A device as claimed in claim 9 wherein the rebound element is limited in longitudinal movement and the conductor is spaced therefrom until operation is to occur.

11. A device as claimed in claim 1, wherein for the purpose of transforming the movement amplitude the sound conductor is connected to an ultrasonic transducer in the proximity of a movement node.

12. A device as claimed in claim 11, wherein the ultrasonic transducer is a piezoelectric compound oscillator which is stepped in itself in order to increase the output amplitude.

13. A device as claimed in claim 12, wherein the ultrasonic transducer in pulse operation works with a steep transient flank.

14. A device as claimed in claim 12 wherein the piezoelectric transducer is with an axial hole and is fixed but slidable along the sound conductor.

15. A device as claimed in claim 1, wherein the spiral tubular probe is encased in a flexible sheath.

16. A device as claimed in claim 15 wherein the sheath has an end adjacent the rebound element that is folded inwardly and including means for fastening said end to the central portion of the rebound element whereby the rebound element can be pushed out of the hose by the sound conductor, while in the retracted state the element is covered by the sheath.

17. A device as claimed in claim 15, wherein at its front end the sheath surrounding the spiral tube is turned in and includes means for liquid-tightly joining the sheath to the rebound element in such a manner that it enables the rebound element to be extended by contact with the conductor, while in the retracted condition it surrounds and protects the rebound element.

18. A device as claimed in claim 17, including means for introducing a fluid into the sheath to cause expansion thereof at the area of the turned-in portion of the sheath.

19. A device as claimed in claim 15 wherein said sheath is flexible and includes a major portion which surrounds the spiral tube and at least a part of the rebound element and a reverse turned portion.

20. A device as claimed in claim 19 wherein said reverse turned portion of the sheath defines an end of the sheath and means for liquid-tightly joining the said end of the sheath to the rebound element, said sheath being flexible enough to permit the rebound element to extend from the sheath when the device is operated, while permitting the sheath to surround the rebound element in its retracted position.

21. A device as claimed in claim 20 including means for introducing a fluid into the sheath to cause expansion of the sheath in the area between at least a section of the major portion and the reverse turned portion.

Claims

1. A device for fragmenting urinary calculus in combination with a cystoscope and comprising a liquid-tight flexible tubular probe means, said cystoscope having guide means for accommodating the probe means, said probe means slidably mounted in the cystoscope, a flexible, elongate sound conductor extending through the probe means from one end to the other end of the probe means, a rebound element disposed at the other end of the probe means having at least one cutting edge and loosely mounted in relationship to the conductor, said probe means including means at the other end of the probe means for slidably receiving said rebound element, and means for oscillating said sound conductor ultrasonically whereby said rebound element in response to the conductor is cyclically slidable and independently movable of the conductor to contact and fragment the urinary calculus.