JPH0349575B2 - - Google Patents

Abstract

An arrangement, for surgical or medicinal use, involving a spiral spring (l) together with a device through which this can be made to expand from a first position (fig.3; 5) with a certain diameter, to a second position (fig.2; 4) with a larger diameter and vice versa; whereby the device (4l, 42b, 43) is designed , whilst keeping the same length (L) on the spring (1; 36) , to turn the spring's ends (38, 39) relative to each other so that the transition from said first position to said second position takes place through a reduction in the number of turns in the spring within said length (L) and a corresponding increase in the spring's ascent (s) or, in order to supply further spring material (B) for a given length (L4) of the spring (1), on at least one end of the spring's (1) said length (L4) so that the transition from said first position to said second position takes place independently of the extension and the number of turns of the spring within said length (L4).<IMAGE>

Description

TECHNICAL FIELD The present invention relates to a device that can be applied, for example, inside a blood vessel in the body of a living animal or a living human being. The device includes a helical coil spring that can be expanded from a first state of a predetermined diameter to a second state of a larger diameter and vice versa.

The present invention is particularly useful for mechanical transluminal implantation with expanding devices for blood vessels, airways, or similar sites. With this device of the invention, the inner walls of damaged blood vessels or other organs can also be lined with artificial tissue, which can be porous.

In surgical technology and other medical technology,
For example, it is often necessary to insert and dilate a blood vessel, urinary tract, or other inaccessible site, the function of which is to widen said blood vessel, urinary tract, etc., and where the device is left in place to provide permanent dilation.

The device according to the invention can be used in a number of mechanical applications, and examples include: to different forms of aneurysms brought about by certain forms of blood vessel dilation or vice versa narrowing, including blood vessel constriction. The use of More specifically, therefore, the present invention supports and preserves ostitized vessels of the venous system, supports vascular graft elements, closes sites of pathological vascular disruption, and prevents pathological vascular hypertrophy. and can be used to bridge fracture sites in the inner walls of blood vessels or to stabilize bronchial tubes or bronchi. The present invention can also be designed to act as a thrombotic filter to prevent pulmonary embolism formation, for example by application to the inferior vena cava. However, the present invention is not limited to the above-mentioned applications;
These applications must be considered as examples only.

[Background technology]

US Pat. No. 3,868,956 describes a device that can be expanded after being inserted into a blood vessel, for example. The working part of this device is based on the use of metal alloys with a so-called "memory effect", ie substances that return to their initial form when heated. In this prior art, the heating of the material is carried out by electrical heating, and the device is inserted at critical locations. However, this known technique has the fundamental disadvantage that electrical resistance heating has to be carried out in conjunction with surrounding sensitive tissue, which may be damaged during heating. Indeed, the above-mentioned US patent specification (see column 3, lines 42-48) states that the patient's blood vessels are used as a cooling medium when the device is inserted into the blood vessels, but blood also serves as a cooling medium. It is also a heat-sensitive material that produces undesirable coagulation when heated.

[Summary of the invention]

It is an object of the invention to provide an expansion device that avoids the deficiencies of the known technology.

The invention is based on the use of a device with a helical coil spring that can be expanded and contracted. The invention is based on the principle that a spring can be given a smaller or larger diameter by means of a suitable mechanical device. This can be done in two main different ways, all within the framework of the same basic inventive concept. Below, these methods will be described for two examples.

The first method is to rotate the ends of the spring relative to each other while keeping the length of the spring constant, thereby reducing the number of turns of the spring within said fixed length and increasing the pitch of the spring accordingly. This consists in causing a transition from a small diameter to a large diameter of the spring to occur. A second method of changing the diameter of a spring is to remove a portion of the spring material from a length of spring at at least one end of the length so that the change from a larger diameter to a smaller diameter is achieved within said length. The purpose is to make this occur regardless of the pitch of the spring and the number of turns. To expand the spring in any of the other ways described above, the reverse operation is, of course, performed. That is, additional spring material is supplied to said length of spring. This second method of changing the diameter of the spring can be accomplished, if desired, by maintaining the pitch and number of turns of the spring within the aforementioned lengths.

Of course, both of the above methods can be used to change the coil spring from a larger diameter condition to a smaller diameter condition and vice versa.

In a preferred embodiment of the device according to the invention, the larger diameter corresponds to a greater extent to the unloaded state of the coil spring. This means that the contraction of the spring occurs against its spring resistance, while its expansion occurs when the tension is removed to an unloaded state.

While using the first method outlined above of expanding and contracting a spring, one end of the spring can be attached to a shaft located centrally inside the spring, while the other end surrounds said shaft. connected to a sleeve. By relative rotation of the shaft and/or sleeve, the diameter of the spring can be increased or decreased. The shaft and sleeve can be removably connected to the spring to allow the coil spring to be removed after being applied in a location.

When using a coil spring with smaller dimensions for the spring material, it is important to note that in connection with applying and expanding the spring in the intended location, the turns of the spring of another material may be biased to one side. Sometimes a problem arises in that the desired support effect is not achieved. To eliminate or reduce the possibility of such spring collapse, an axially extending guide bar can be placed around the circumference of the spring. The guide bar is displaceably disposed around the circumference of the spring so that the spring material can move tangentially in relation to expansion and contraction of the spring.

In a further embodiment according to the invention, an axially extending support device can be arranged around the circumference of the spring carrying the fixed guide device. Via this fixed guide device, the spring material can be moved tangentially in relation to the expansion and contraction of the spring.

In some cases, for example in the case of a hernia or tissue rupture, it may be desirable to apply a spring with greater density between the turns of the spring over a limited portion of its length. This can in principle be done in two different ways. Another method is based on distributing the fixed guide means described above in such a way that a greater winding density is obtained over a given length of the spring. A second alternative method consists in manufacturing the spring initially in one or several parts with a higher winding density. Of course, a combination of these two other methods can also be used in practice.

In view of the aforementioned crushing risks, the spring material should be manufactured in a flattened form or in the form of a band, and the larger dimensions of the material should be chosen to be arranged in an axially extending cross section. It is particularly preferred to design the spring to have an essentially rectangular cross section.

In one particularly preferred embodiment of the invention,
A cylindrical tubular carrier body is disposed within the coil spring and has a central portion and end portions at each end of the spring that pivot relative to each other, the ends of the spring being connected to the respective end portions. The device further comprises means with the aid of which the end parts can be rotated relative to each other in order to expand and contract the spring. The means for rotating said terminal section preferably comprises a coaxial cable connected to one terminal section, the internal coaxial element of said coaxial cable extending through the carrier body and having its end connected to the other terminal section. A rotor is disposed at the outer free end of the coaxial cable to connect the sections and to provide the desired relative movement between the terminal sections.

In connection with this latter embodiment of the device according to the invention, the terminal parts of the carrier body can be axially displaced relative to the central part, so that the distance between the central part and the respective terminal part is The end of the spring can be releasably mounted. In this case, it is preferable to arrange at least one end of the case so that it can be displaced in the axial direction by a member arranged at the free end of the coaxial cable. A member located at the free end of the coaxial cable is adapted to optionally serve the dual function of rotating and axially displacing the second terminal portion.

In one particularly preferred embodiment according to the invention, an axially extending support element is arranged around the spring. A spring is attached to one end of the support member, and a fixed guide member is provided at the other end. Spring material can be moved through this guide member in connection with expansion and contraction of the spring.

Alternatively, fixed guide means can be arranged at both ends of the support member, through which the spring material can be moved. In this embodiment, the spring material can be fed simultaneously in both directions at both ends of the spring.

According to another embodiment, the apparatus of the invention comprises: an elongated carrier body around which a spring is disposed; a cassette housing disposed at one end of said carrier body including a cylindrical cassette housing;
and a feed cylinder eccentrically mounted within the cassette housing, the feed cylinder having a peripheral portion thereof engaged with the inside of the cassette housing. This device can be used to move the spring to expand and contract within the nip between the cassette housing and the feed cylinder by rotating the feed cylinder in one direction or the other. In this embodiment, a trapezoidal thread can be provided on the inside of the cassette housing, in which the spring can slide. In addition, it is advantageous to provide the outer surface of the feed cylinder with a friction coating, for example of rubber or plastic.

In surgical procedures for transplanting artificial blood vessels, it is often desirable to provide porous tissue inside the blood vessel for certain reasons, for example. In this connection, according to the invention it is possible to provide a porous stocking on the outside or inside of the spring,
The stockings can be implanted with springs in the desired position. The stockings can be adjusted to the diameter of the spring by virtue of the elasticity of the porous tissue or by folding overlappingly.

Regarding the selection of the materials of the components included in the device according to the invention, what is critical in this respect is first of all the helical spring. As the spring material, a pharmaceutically acceptable material should be selected, for example stainless steel or other metal alloys or similarly used plastics.

Other features and further embodiments will be apparent from the following description and from the claims.

A further fundamental advantage of the technique of the present invention over that described, for example, in the above-mentioned U.S. Pat. and then, before releasing the spring from the other parts of the device, the position and fixation of the spring can be inspected, for example by X-rays, for acceptability;
The spring can then be released and the remaining part of the device removed from the application position. This possibility is not available at all with the device according to the US patent just mentioned, since it is not possible to reverse the expansion operation initiated in this known technology.

〔example〕

The invention will now be explained in more detail by way of example embodiments in conjunction with the accompanying drawings, in which: FIG. It should be noted that these embodiments are intended merely to illustrate the invention and not to limit its scope, which is defined by the claims. The following figures are illustrated in the accompanying drawings.

1 shows a perspective view of a coil spring for use in a device according to the invention; FIG. 2 shows a side view of the coil spring housing the carrier body and shows the spring in an expanded state; FIG. 2 shows the same device as that shown in FIG. 2, but showing the spring in a contracted state; FIGS. 4 to 7 schematically illustrate the principle of removing spring material from a coil spring according to the invention; 8 and 9 show a variant embodiment based on the same principle as that according to FIGS. 4 to 7, and FIG. 10 diagrammatically shows the possible performance of a coil spring under the action of an external force. 11 shows details of a coil spring using a guide device, FIG. 12 shows an enlarged view of the device of FIG. 11, and FIG. 13 shows a detailed view of FIG. 12 cut along the - line. 13A schematically shows a spring with a support member and a fixed guide member, FIG. 13B shows a detail of the embodiment of FIG. 13A, and FIG. 14 shows a spring with a support member and a fixed guide member. 15 shows a detail of another guide element, FIG. 16 shows the guide element according to FIG. 15 as seen from above, and FIG. 17 shows an arrangement of the device according to the invention. FIG. 18 schematically shows a general view of an embodiment of the invention, FIG. 19 shows an enlarged detail of a further embodiment of the device according to the invention, and FIG. 20 shows a side view of the detail shown in FIG. 19, FIG. 21 shows a device according to the invention for applying a porous tissue, and FIG. 22 shows a flat spring material with recesses. 23 shows an embodiment designed as a ladder-like double spring, and FIGS. 24 and 25 show an embodiment using a coil with adjacent windings that can overlap. 26 shows a variant embodiment of the spring of this device, the spring shown has an overload, and FIG. 27 shows the spring covered with a porous tissue. 3 shows another embodiment.

In the following description, the device according to the invention is used on a blood vessel containing a defect location, where the blood vessel has a relatively large diameter, while at the location where the device is introduced into the blood vessel. It is assumed that the blood vessels have a smaller diameter. However, the device according to the invention is also useful when the device is inserted into a blood vessel having a relatively constant diameter, thereby avoiding damage to the internal vessel wall associated with insertion of the device for transfer to the site of application. can also be used.

The device according to the invention therefore allows the coiled spring of the device to be maintained in a contracted state by mechanical means, said contracted state being small or smaller than the diameter of the blood vessel at the insertion point so that the blood vessel in question is It has a relatively small diameter and can be inserted at an easily accessible location. The device with the coiled spring is then inserted into the blood vessel and moved to the defect location. At the defect location, the coil spring is mechanically expanded until the outer diameter of the spring is equal to or slightly larger than the diameter of the blood vessel at the defect location. The coil spring can then be advantageously released from the other parts of the device according to the invention and left in the defect position to perform its supporting function from the medial side after removal of the remaining parts of the device. If the unloaded diameter of the spring is selected to be slightly larger than the inner diameter of the blood vessel, the spring will engage the inner wall of the blood vessel with a certain pressure and fix the blood vessel. The magnitude of this particular pressure can be calculated in advance and thus chosen as desired.

1, 2 and 3 of the accompanying drawings,
It is shown in principle how the diameter of a helical coil spring according to an embodiment of the invention can be varied. FIG. 1 shows the longitudinal axis 2 schematically.
FIG. The ends of the spring are labeled 3 and 4. 1st
The coil spring in the figure shows the shape when it is not receiving any external force (hereinafter referred to as the "rest position"). If the ends 3, 4 of the spring are caused to rotate about the longitudinal axis 2 in the direction of the arrows 5, 6 by the action of an external force, the diameter of the spring decreases and the number of turns of the spring increases accordingly. do. FIG. 2 shows the coil spring 1 in a side view in the rest position. In Figure 3,
1, the same spring 1 is shown in a reduced diameter state. The spring 1 is given a diameter d3 in the position of FIG. 3, which is 1/3 of the diameter d2 of FIG. 2, and the number of turns of the spring is three times the number of turns in the rest position. . Since the length L of the spring remains unchanged, the pitch s3 of the coil spring in the position according to FIG. 3 is 1/3 of the pitch s2 in the rest position according to FIG.

In FIGS. 2 and 3, a cylindrical central body 7 is shown in dashed lines, the function of which is to stabilize the spring 1 in the contracted state according to FIG.

4 to 7 illustrate the principle of another embodiment according to the invention. According to this embodiment, the diameter of the coil spring is such that it occurs without changing the pitch of the spring. The coil spring 1 in the rest position according to FIG. 4 has a diameter b4, a length L4 and a pitch s4. In FIG. 5, the same spring is shown, but with a diameter d5 reduced to about half the diameter d4 according to FIG. However, in this state the spring has two parts A and B of different pitches. Part A is the length L4 and pitch s that the spring has in its rest position.
4, while part B has lengths L5 and s significantly smaller than L4.
It has a pitch s5 which is considerably smaller than 4.
The reduction in diameter from the rest position according to FIG. 4 to the position according to FIG. 5 is obtained by rotating the ends of the spring in the same manner as shown in FIGS. 1 to 3. In this way, the division of the contracted spring into two regions of different pitch can be achieved by suitable mechanical means.

FIG. 6 shows the same spring 1 as in FIG. 4, but with a diameter d6 reduced to approximately half of the diameter d4. This spring has two parts C and D. Portion C has the same length and pitch as the length L4 and pitch that the spring has in its rest position. In part D, the spring 1 forms a concentric flat helical spring.

FIG. 7 shows an end view of the helical spring according to FIG. 6, from which the appearance of section D is clearly visible. Therefore, in this embodiment, the overall length L4 and pitch s4 of the spring are the same as the overall length and pitch of the spring in its rest position. The change from the rest position of the spring 1 to the state according to FIGS. 6 and 7 can be effected by suitable mechanical devices.

1 to 7 it has been shown how the diameter of a helical coil spring according to the invention can be varied, for example to enable surgical operations. In the following, different practical solutions will be described to enable the coil spring to expand and contract as desired.

Part B of the embodiment according to FIG. 5 can also be considered as a storage part of the coiled spring material, which supplies part A of the spring material in the expanded state. 8 and 9 show side and end views, respectively, of an apparatus in which the principles just described are applied. In the storage part B, the helical turns are arranged closely together. Figures 8 and 9 are 2
Feeding takes place through a nip formed between two oppositely rotating small feed rollers 15 and 16, whereby the helical material is fed progressively in the direction of arrow 18 and is delivered at the nip end 17 of the rollers. This diagram schematically shows a mode in which the control is performed so that the Figures 8 and 9 show portion A of the coil spring after it has been expanded to its rest position.

For the application of a coil spring with the device according to the invention, it is of course also possible to change the length of the spring as required by external manipulation after application in order to adapt it to different situations. Thus, the spring can be axially compressed before, during, and after expansion, thereby allowing it to subsequently expand axially, e.g., to a neutral, unloaded state, and even beyond the neutral state to an expanded state. I can do it. In this latter case, the spring can be made even more stable in terms of the tension stored in the spring.

When applying the technique according to the invention to human surgery, it is preferred that the diameter of the coil spring in the contracted or reduced state is not greater than 8 mm to 10 mm. The diameter of the spring in the expanded state may range from 12 mm to 30 mm. For a coil spring made of stainless steel wire with a thickness of about 0.3 mm, for example from 8 mm to
Expansion up to 12mm, i.e. 50% expansion or
An expansion number of 1.5 (12/8=1.5) is obtained. It has been found that using this wire material it is not possible to produce a coil spring with a diameter of approximately 30 mm in the expanded state in the rest position. Investigations revealed a relationship between material thickness and expansion number for all spring materials involved. This relationship depends on the material, but
Generally, the higher the desired expansion number, the thinner the line material should be selected. As an example, to go from a contracted state with a diameter of 8 mm to a rest position with a diameter of 30 mm, i.e. to obtain an expansion number of 3.8, a steel band of stainless steel material with a width of 1 mm and a thickness of approximately 0.15 mm is required. You could say that. Quite generally, a suitable spacing in terms of line or band thickness is about 0.08 mm to 0.30 mm. Regarding the width of the band material, a preferred spacing is about 0.3 mm to 2 mm. In other words, this means that in order to use the technique according to the invention for surgical purposes, thin materials in the form of wires or bands must be used to manufacture coil springs in large and low cases. There is. However, coil springs based on such materials support blood vessels quite satisfactorily, for example when applied to a defective blood vessel.

In practice, it has been found that coil springs made of thin materials have a tendency to become mechanically unstable in the expanded state. This therefore causes the spring to tilt and collapse after application. FIG. 10 schematically shows the manner in which a coil spring 1 made of thin material is unstable due to instability in the expanded state after application. The dart line shows the wall of the blood vessel with an internal spring expansion. Such instability of coil springs is often unacceptable. This is because the coil spring is unable to perform its intended function of eliminating the aforementioned defects, but rather acts to restrict blood flow.

According to the invention, the possibility of such a collapse of the spring occurring can be eliminated or at least essentially prevented by providing the helical spring with a locking device that acts on the helical spring both in the contracted state and in the expanded state. be able to. 11th
Figures 12 and 13 illustrate one embodiment of the device according to the invention with such a fixing device. FIG. 11 diagrammatically shows a portion of the coil spring whose contracted state is indicated by 21 and whose expanded state is indicated by 21a. In this figure, three guide members 22 for the coil springs are shown. As is clear from FIG. 11, the guide member 22
are arranged on a common flexible but relatively rigid line 23 at a distance s12 between them.
12 shows a detail of the device of FIG. 11 on an enlarged scale, and FIG. 13 shows a cross-section of FIG. 12 taken along the - line. Figure 12 and 1
3, the coil spring 21 extends through a hole or opening 24 in the guide member 22, while the thread 23 extends through a hole 25 in the guide member 22.

The embodiment illustrated in FIGS. 5 and 6 is preferably constructed so that the guide member 23 is fixedly attached to the line 23. In this way, the pitch s12 is maintained in a contracted state as well as in an expanded state, all consistent with the foregoing description with respect to FIGS. 5 and 6.

FIG. 13A shows an embodiment of a coil spring stabilized by a fixed guide member in the expanded state. A coil spring 21, preferably made of a thin metal band, is fixedly attached at its end 21a to an axial support member 23a. The support member 23a preferably consists of one or two flexible bands attached to each other. The other end 21b of the coil spring 21 is connected to the support member 23a by a single fixed guide member 22a in the form of a loop with a rectangular opening. It has surprisingly been found that it is sufficient that the spring 21 in this embodiment is sufficiently stable for practical use and that the ends of the spring 21 are stabilized and interconnected by the support member 23a. An advantage of this embodiment with a single guide member is that the spring only needs to be threaded through a single guide member, making it easier to expand and contract the spring.

Figure 13B shows an enlarged view of the preferred design of guide member 22a and its connection to support member 23a. The guide member 22a is formed using a band having a loop-shaped protrusion, and this band, together with the support member 23a, has a rectangular recess 22a.
is formed. The spring band 21 can easily slide into the recess 22a and be stabilized at the same time.

In addition, as another aspect, FIG. 13A and FIG.
The last described embodiment according to FIG. 3B can be modified by arranging fixed guide members at each end of the support member 23a. In this way,
The spring band material can be fed into or out of the ends of the spring 21;
This is also advantageous in large expansion numbers when, at the same time, a longer length of spring band material must be stored at both ends of the spring in connection with the contraction of the spring.

For this embodiment, if the fixed point 21a
and 22a is greater than the normal length of the spring in the neutral unloaded state, the spring can be better stabilized in the expanded state.

However, in the embodiment according to FIGS. 2 and 3, the guide member 22 is arranged such that it can be displaced on the line 23, so that the pitch of the coil spring can be varied in accordance with the above-mentioned considerations.

FIG. 14 diagrammatically shows a side view of the coil spring stabilized in this way in the extended rest position.

It has been mentioned above that the material of the helical spring is preferably in the form of a wire (thread) or band, that is to say that the material of the helical spring has a circular or flattened shape in axial cross section. It has been found that coil springs made of material in the form of bands are more stable and less prone to tipping or collapsing. However, generally the width of the band is 1mm or more for medical reasons.
It should not exceed 1.5mm. Increasing this width further impedes tissue growth, resulting in lower specific engagement pressures and therefore less fixation. A higher specific engagement pressure is preferred since it provides better fixation, which is essential for application of the spring into the blood vessel, resulting in axial displacement of the applied spring with a pulse rhythm.
One way to improve the locking of the spring is to roughen the outer surface of the spring material, for example by blast finishing. The spring material can also be formed with outwardly extending protrusions by stamping, or alternatively, the band material can be perforated, for example by stamping or by using a laser, thereby Good fixation is obtained and tissue growth is facilitated in the area where the spring is applied.

FIG. 15 shows an enlarged view of an embodiment of the guide member which provides good spring stability even at large expansion numbers. The guide member 27 is provided with a rectangular recess 28 for guiding a band-shaped coil spring 29, as shown in cross section. Preferably, the dimensions of the recess 28 are selected such that the coil spring member 29 can easily slide through the recess when the spring is expanded and contracted.
At the same time, the tilting of the coil spring is prevented, so that the tilting force is absorbed by the guide member and the wire associated with the guide member arranged in the hole 25.

Figure 16 shows the corresponding guide member 3 seen from above.
Indicates 0. The dart line 31 indicates a recess with a rectangular cross section, and the dart line 32 corresponds to the hole 25 in FIG. As is clear from this figure, center lines 33 and 34 intersect each other at 90° different angles. Thereby, the guide member can be adjusted to the pitch angle of the coil spring with respect to the line, and in this way the movement of the coil spring is facilitated when changing the diameter of the spring.

FIG. 17 shows an embodiment of the device according to the invention in the form of an instrument 35 for performing a surgical operation.

A coil spring 36 is arranged around a cylindrical carrier body 37 in a contracted state. The carrier body 37 has a tubular central portion 47 and end portions 40,41. Terminal part 40, 4
1 can be rotated relative to each other by a rotating ring 45 and can be displaced in the axial direction with respect to the central part 47. At one end of the carrier body 37, a flexible coaxial cable 42 is connected to one end portion 41i. This coaxial cable 4
2 comprises an outer tubular portion 42b and an inner element 42a. The inner element 42a extends through the end portion 41 and all the way through the central portion 47 of the carrier body 37 to the second end portion 40 and is rigidly attached to the second end portion 40.

A head member 4 is attached to the free end of the coaxial cable 42.
3 and 44, one of which, the head member 43, is connected to the outer portion 42b of the coaxial cable 42.
while the other head member 44 is connected to the inner element 42a of the coaxial cable 42.

One end 38 of the coil spring 36 is connected to the terminal portion 4
By displacing the carrier body 37 in the axial direction, it can be clamped in a slit 46 formed between the central part 47 and the end part 40 of the carrier body 37. The other end 39 of the coil spring 36 can likewise be clamped in a slit 48 formed between the end part 41 and the rotating ring 45 by axially displacing the end part 41.

The clamping of the ends 38, 39 of the coil spring 36 in the slits 46 and 48, respectively, and the release of the ends 38, 39 from the slits 46, 48 are performed by operating the head member 44 inside the coaxial cable 42. This can be done by an axial displacement of the element 49. The head member is also manipulated to produce axial displacement. Both ends 38 of the coil spring 36, according to the principle illustrated in FIGS.
The relative rotation of the head members 43 and 44 can be performed by rotating the head members 43 and 44 relative to each other.

In the device shown in FIG. 17, the central through passage 49
is formed. Channel 49 allows control fluids and other instruments for medical investigations to be injected and inserted into the blood vessel.

The functions of the illustrated device are briefly described as follows. In the state shown in FIG. 17, that is, the state in which the coil spring 36 is contracted, the coil spring 3 attached to each slit 46, 48 is
6 is inserted into an easily accessible location of the blood vessel in question and quickly inserted into the defect location having a larger diameter. Expansion of the coil spring 36 is obtained by rotating the head members 43, 44 relative to each other. coil spring 36
has expanded to a tension-free or substantially tension-free state, the ends 38,3
9 is released by axially displacing the head members 43, 44 relative to each other and widening the slits 46, 48. In this way, both ends 38, 39 of the coil spring 36 are released, and then the coaxial cable 4
2 and a supporting body 3 attached to the cable.
7 can be removed from the blood vessel.

FIG. 18 shows another embodiment of the device according to the invention in the form of an instrument, generally designated 51, for performing a surgical procedure. This device is the fifth
It is based on the illustrated spring principle and relates to the embodiment shown in FIGS. 13A and 13B. In FIG. 18, spring 52 is shown in a contracted state. An axially extending support means 53 of the spring 52 is rigidly attached to one end 54 of the spring, while the end of the spring 52 is movable through a guide member 55 arranged on the support member 53. The spring 52 and support member 53 are attached to a cylindrical resilient hollow body 56 by latches (not shown), one at each end of the support means 53. These latches are connected to the support member 5 by, for example, each wire extending inside a hollow body 56 and a coaxial cable 57 connected thereto.
3 can be released from both ends and thus can be controlled from the outside in this way.

Between the coaxial cable 57 and the end 55 of the support member 53, a spring is wound relatively closely around the carrier body 56 as shown at 58. An end 62 of spring 52 adjacent coaxial cable 57 is releasably connected to sleeve 59. The sleeve 59 surrounds the cylindrical carrier body 56 and can be rotated and moved axially by a flexible tube arranged concentrically within the coaxial cable 57.

Expansion of the spring 52 is effected by rotating the sleeve 59, so that the extra portion of the spring stored adjacent to the sleeve 59 expands simultaneously with the spring 52 moving through the guide device 55. During expansion of spring 52, sleeve 59 is gradually moved forward by axial movement of the flexible tube.

The overall length of spring 52 is preadjusted so that only a short length of spring material is disposed outside guide member 55 when expansion of the spring is blocked by the surrounding inner wall of the blood vessel. When the surgeon confirms that the spring 52 is in its correct position, the spring 52 is released by releasing the latch and the attachment portion of the end 60 along with the carrier member 53. If the length of the spring selected for the application of this device proves to be inadequate and needs to be replaced, this change can be made by rotating the sleeve 59 in the opposite direction to remove the latch and end 60. Spring 52 before releasing
This can be done by shrinking . Thereby, the device can be removed and spring 52 replaced with another spring having a suitable overall length.

According to another embodiment of the invention, the hollow body 56
An extra portion 58 of the spring, wound closely on the outside of the
) can be fed out of the sleeve through the sleeve. This embodiment is shown in axial and radial section in FIGS. 19 and 20, respectively.

According to this embodiment, the feed cylinder 63 is mounted eccentrically within the cylindrical housing 61. Inside the housing 61, the cam 66 is cut to form a trapezoidal internal thread 67. The outside of the feed cylinder 63 is covered with a rubber layer 64.

When using this device, a coiled spring band material 72 is placed inside the trapezoidal screw 67 and a rubber layer 64 provided on top of the feed cylinder 63.
presses into engagement with band material 72 along distances 68-69 (FIG. 20). Now, if the feed cylinder 63 is rotated in the direction of the arrow 71, the spring band 72 will cause the guide member 55 (first
8) and at the same time the spring expands. Feed cylinder 6 with rubber layer 64
3 engages the inside of the trapezoidal screw 67 along its entire length.
If is rotated in the opposite direction, the spring band 72 can be retracted rearward, causing the coil spring to contract.

The advantage of storing the extra portion of spring material in the casing according to FIGS. 19 and 20 is significant. Therefore, the expansion and contraction of the coil spring does not disturb or irritate the surrounding tissues in any way in view of the extra portion of the spring being enclosed within the casing. Moreover, the terminal guide member 55
The feeding mechanism and guidance of the spring through (FIG. 18) provides a very uniform and controlled expansion of the spring along its entire length. This latter fact means that the implantation of the spring becomes considerably easier.

In some cases, it may be desirable to line the inner wall of a damaged blood vessel or other organ with, for example, a porous synthetic tissue, for example, to prevent rupture of the blood vessel. All such linings can be applied using the device according to the invention.

FIG. 21 diagrammatically shows a cross-section of the spring 21 according to FIG. 13A in the retracted state with support member 23A. A porous tissue in the form of a cylindrical stocking 73 is disposed around the spring 21 and attached by thin wires 24 to the carrier member 23A. This tissue 73 is folded overlappingly at fold positions 75 and 76 to tightly surround the contracted spring 21. The stocking 73 is held in this position by an axially extending thin metal wire 77 located at the bending position 75.

After the spring 21, together with the stocking 73 surrounding it, has been inserted into the injury site, for example by means of an instrument according to FIG. 17, the metal wire 77 is removed, thereby expanding the spring 21. During the expansion of the spring 21, the stocking 73 is fully opened and eventually tightly engaged inside the injured area of, for example, a blood vessel.

As an alternative to the embodiments described above, the cylindrical stockings can of course be made of elastic material. The stretchable material can be stretched to an expanded state without double-folding the material in conjunction with the expansion of the spring. As such materials it is possible to use, for example, fine mesh articles of the tricot type, for example round sewn or round braided. Such alternative embodiments may, of course, be used, for example, when a device with a spring in a contracted state is inserted into a blood vessel of relatively constant diameter, and the internal surface of the blood vessel associated with insertion of the device into the blood vessel. It is particularly useful at smaller dilatation numbers where some degree of constriction is required relative to the internal diameter of the vessel to avoid damage.

It should be understood that the invention is not limited to the embodiments described above, which are intended merely to illustrate the invention. Thus, instead of the eccentrically mounted feed cylinder 63, the housing shown in FIGS. 19 and 20 may house any suitable feed device capable of moving the spring in and out of the casing 61. can. Possible alternatives include a concentrically arranged spring that is moved axially in connection with the retraction of the spring and rotated back into the housing 61 after completion of spring feeding and before removing the device from the application site. For example, a feed roller or a feed screw may be mentioned.

Additionally, the embodiment described with respect to FIGS. 13A and 13B using a guide member fixed to each end of the spring for simultaneous feeding at both ends of the spring allows the midpoint position of the spring to carry member 23A. It can be designed to be firmly attached to the

In the embodiment shown in FIG. 22, the spring consists of a band-shaped material 78 with an elongated opening 79. The opening 79 is formed, for example, by punching. In this way, the spring is formed in the shape of a ladder. Spring 78, which can be expanded like the spring of FIG. 1, exhibits very good stability and eliminates the possibility of spring tilting in the manner shown in FIG. By suitably selecting the thickness of the band and the width of the stepped remainder of the band, it is possible to combine good stability with high expandability from small to large diameters.

By another aspect other than punching out the opening, the 22nd
A spring can be manufactured with good stability similar to the spring shown in the figure. Accordingly, FIG. 23 shows a ladder-shaped spring made from round wire instead of a flat band. In this case, the spring is manufactured by first forming a ladder-shaped section by attaching two adjacent parallel wires 80 and 81 by transverse elements 82. This device can also be viewed as a double spring consisting of two unitary springs 80 and 81.

As previously mentioned, it is often necessary to line the interior walls of damaged organs with some tissue. In FIG. 23, a device for introducing such tissue into a damaged organ is shown. It should be noted that although this device is illustrated with respect to the particular spring shown in FIG. 23, this device is of course applicable to all types of coil springs.

The spring of FIG. 23 is surrounded by a stocking 95 of some porous material. stockings 95
is attached to a longitudinally extending rod or rigid wire 94 by stitches or the like indicated at 97. Wire 94 is then attached to springs 80, 81 at intersection 96 in a suitable manner, for example by spot welding, glue gluing or similar means.

This configuration allows the spring to serve as a graft, for example in implantation in a blood vessel;
And because the stocking 95 is secured to the axially extending wire 94, the stocking 95 is fixed in place during the entire application operation, so that after application into the blood vessel, the entire stocking 95 is attached to the spring 8.
0,81 to form an artificial tissue in the blood vessel.

Stockings 95 are preferably made from some stretchable porous material that is capable of following the spring material as it expands in conjunction with application at the intended location. Accordingly, the stockings 95 may be constructed of any knitted or sewn material of the tricot type or some type of crepe product having the required elasticity. An alternative material is a stretchable plastic film, ie an elastic body of silicone resin, for example.

The embodiment shown in FIGS. 22 and 23 is an alternative to the embodiment just described, in which porous materials,
For example, it can be used as a carrier for the tissue illustrated in FIG.

A ladder spring 83, designed for example like the spring of FIG. 22 or 23, is coated with a porous material 84. However, in order to obtain the desired density between the turns of the spring, a double support is provided in that a lateral step of the ladder corresponding to element 82 in FIG. 23 is configured in step 85. The spring has been slightly modified. In this way, the turns of the spring can overlap each other to obtain the desired density. FIG. 25 shows an enlarged axial cross-section of two adjacent turns of the spring of FIG. 24. As can be seen from FIG. 25, the transverse element 82
has a shoulder portion 86. This spring is covered with a porous tissue 84.

As is clear from FIGS. 24 and 25,
For example, a seal can be obtained even if the spring moves axially. This is important if it is desired to use, for example, the device according to FIG. 17 to expand the spring. Since the distance between members 38 and 39 is constant, the pitch of the spring is changed when these members 38, 39 are rotated relative to each other. The use of the embodiment of FIGS. 24 and 25 allows pitch changes by rotation of members 38, 39 while maintaining a seal in view of the transverse elements 82 sliding axially relative to each other. For example, the overlap of the turns of the spring is relatively large when the spring is installed in the device according to FIG. A spring according to FIG. 24 can be designed.

If it is desired to maintain the same pitch in the contracted and expanded states of the spring according to, for example, FIGS. This can be done by modifying the apparatus of Figure 17 to move axially towards or away from each other. In this way, the pitch can be maintained relatively constant, which is particularly important with respect to the embodiment of FIGS. 22-25.

In some cases, it may be advantageous to design the porous tissue in the form of a semi-permeable section of band-like material, rather than attaching it to the outside of a ladder-shaped device. Therefore,
In this case, the opening 79 in FIG. 22 can be replaced by a thinly formed body of band material;
Also, very fine holes are formed so that the same perforation surface can be obtained when forming thinly. Also in this case the transverse elements 78 provide the necessary fixation.

A further advantage of the device according to FIG. 24 is that the porous material does not necessarily have to be elastic in order to participate in the expansion of the spring.

FIG. 26 shows a variant of the design of the device according to the invention. The modified spring shown in Figure 26, generally designated 90, is designed as a conventional spring having a constant diameter over most of its length, while at its upper end 91 it is designed to have a reduced diameter. 26, so that spring 90 has the configuration shown in FIG. 26 in the unloaded state. To facilitate the following description of the function of the spring, the lower free end of the spring 90 is designated 92, while its upper free end is designated 93.

With respect to the contraction or expansion of spring 90 when applied to its intended position, the function of the spring shown in FIG. 26 is the same as that of the springs of the previously described embodiments. However, in view of the fact that spring 90 is provided with a reduced diameter end 91, some modification of the instrument to be used to actuate the spring may be desirable. For example, the apparatus shown in FIG. 17 removes the end portion 40 and inserts a lateral end portion 40 intended to accommodate and retain the upper free end 93 of the spring 90 in the end inner element 42a extending through the carrier body 37. It can be modified to accommodate a spring according to FIG. 26 by providing a groove. Then the other end 92 of the spring 90
can be held at the other end of the carrier body 37 connected to the terminal portion 41 in the same manner as described with respect to FIG. This allows the spring 90 to be compressed.

When the spring 90 is in the contracted state, the spring 90 can be applied to a desired location within a blood vessel, such as the inferior vena cava for the purpose of preventing pulmonary embolism. Previously known filter devices intended to be applied inside a blood vessel for the purpose of trapping blood clots are those in which such a device is permanently attached within the blood vessel by points or hooks or similar means. This has the disadvantage that it is impossible to modify the position or remove the filter. An example of such a device is described in US Pat. No. 3,540,431.

However, by using a device according to the invention as illustrated in FIG. 23, these deficiencies can be avoided and substantial advantages are obtained. These essential benefits include:

1. A hyperfunctional spring is automatically attached to the inner wall of a blood vessel by non-damagingly engaging the inner wall.

2. The position of the spring can be modified and the spring can be removed.

3 This device only slightly reduces blood flow through the blood vessel cross section.

4. Intravascular application of the device is significantly easier than that of prior art devices.

To prevent blockage of the reduced diameter end 91 of the spring 90 by clotted blood clots, the distance between the spring turns of the reduced diameter portion of the spring is approximately 3 mm. Using such a distance avoids the passage of larger thrombi and prevents premature occlusion of one reduced diameter end.

For the embodiment of FIG. 26, and for other embodiments of the spring of the device of the invention, for example, a spring inserted and applied into a blood vessel can be removed in the manner described below. A flexible tube of diameter adjusted to the blood vessel is inserted into the spring 90 up to the end 92 or further to the other end 93, after which the end of the spring is gripped in a suitable position by the gripping member and its As a result, the spring can be retracted through the tube without damaging surrounding tissue. This technique can be advantageously used when the spring occupies or reaches an incorrect position in the blood vessel.

FIG. 27 shows a variant embodiment of the device according to FIG. 24 or 25, with which the inner wall of a damaged organ can be lined with porous tissue. This embodiment includes a spring of the type illustrated in FIGS. 22 and 23, and the reference number in this figure is
The symbols are the same as those used in Figure 3. According to FIG. 27, the double springs 80-82 are covered by a stocking 83 of porous tissue surrounding the separate turns of the spring along its entire length. Stockings 83 extend laterally to the outside of the spring so that the insides of adjacent turns of the spring overlap as seen in FIG. Also in this case, a seal is obtained if the spring is moved axially and, for example, a device according to FIG. 17 is used to expand the spring.

In other respects, the device according to the invention includes the following features singly or in any combination:

(a) The other conditions mentioned above (FIGS. 2 and 4) substantially correspond to the unloaded condition of the coil springs 1, 36.

(b) shaft 42a and sleeve 42b are releasably connected to coil spring 36;

(c) an axially extending guide bar 23 is disposed around the spring, on which at least one guide member is displaceably disposed, and through which the spring material is guided by the contraction of the spring; or that it can be moved tangentially in relation to expansion.

(d) a fixed guide member 22 is arranged around the spring on a support member 23 distributed over said predetermined length of the spring and extending in the axial direction, the spring material 2
1 moves tangentially through said fixed guide member in conjunction with the expansion or contraction of the spring.

(e) Terminal portion of carrier 37 or portion 4 thereof;
0,41 are axially displaceable with respect to the central portion 47, so that the distances 46,4 between the central portion 47 and the respective end portions 40,41
8 in which the ends 38, 39 of the spring can be releasably mounted.

(f) At least one of the terminal portions 40, 41 is axially displaceable by a member 44 disposed at the free end of the coaxial cable 42.

(g) The support member 23a extending in the axial direction is the spring 21.
One end 21a of the spring 21 is attached to the support member 23a, and the other end 21b of the spring 21 is provided with a fixed guide member 22a, through which the spring material is guided by the contraction of the spring 21. or be able to move in connection with expansion.

(h) an axially extending support member is disposed around the spring, and a fixed guide arrangement is arranged at each end of the support member, through which the material of the spring can move in relation to expansion and contraction of the spring; It's becoming like that.

(i) a spring 52 around an elongated carrier body 56;
A cassette magazine is disposed at one end of the carrier body 56 and includes a cylindrical cassette housing 61 and a feed member 63 rotatably disposed within the cassette housing 61. be able to move to extend or contract the spring by rotating it in one direction or the other.

(j) The feeding member consists of a feeding cylinder 63 mounted eccentrically in the cassette housing 61 and a cylinder 63 whose peripheral portion engages with the inner side of the cassette housing 61.

(k) A trapezoidal thread is formed inside the cassette housing 61 within which the spring 52 can slide.

(l) The feed cylinder 63 is provided on its outside with a friction coating 64, for example of rubber or plastic.

(m) Spring 5 around elongated carrier body 56
2 is disposed and one end of the carrier body 56 is fitted with one end of a spring, and a magazine portion 58 extends from the other end of the carrier body surrounded by a spring carrying a rotating sleeve 59 at its outer end; A spring is releasably attached to the other end of the rotating sleeve 59 and a device is provided for rotating and axially displacing the rotating sleeve 59 relative to the carrier body 56.

(n) The ability of the stocking 73 to accommodate the expansion of the spring and the associated spring diameter due to the elasticity of the porous tissue.

(o) Bent part 7 where stockings 73 overlap
5,76 to accommodate the expansion of the spring and the associated spring diameter.

(p) The stockings 73 are attached to the spring 21, for example by sewing with thread.

In the present disclosure, the term "coil spring" refers to a conventional type of helical spring. However, the material used in the device of the invention need not necessarily have a constant diameter or a constant pitch. However, a common shape is that of a helical wire.

The invention is also useful in certain kidney diseases where so-called hemodialysis is performed. In this operation, a needle or cannula is applied to the patient's arm whereby the patient's blood is extracted from the body and returned to the patient's body after dialysis in the dialysis machine. Because dialysis must be repeated at least once a week, problems arise with the patient's blood vessels. This problem can be solved by creating a so-called bypass, which constitutes a permanent connection between the artery and vein of the patient's arm. This connection can for example consist of a prosthesis or a so-called "solkograft", a vein taken from the calf. The advantage of using such a bypass is that the high blood pressure from the artery allows the connecting vein to dilate the connecting artery and make it easier to access during cannula insertion. Moreover, multiple dialysis runs can be performed before replacing the coupling part. Connecting conduits are usually placed subcutaneously and attached to arteries and veins with sutures.

However, the connections that have been used in the past pose certain problems. When the artificial blood vessel is pulled out from under the skin during operation, the artificial blood vessel can be bent and occluded. After the dialysis cannula is removed, the connecting graft must be compressed to prevent significant blood loss. then,
The artificial vein can be easily collapsed and subsequent blood circulation can be prevented from being obstructed.
It has also been found that so-called stenosis occurs when the connecting part is attached to a vein.

It has now been found that the disadvantages associated with the connecting conduits or vascular grafts described above can be eliminated by using the device of the invention in the following manner.

A coil spring having a suitable diameter and a suitable number of turns is attached to a device according to the invention, such as that illustrated in FIG. 17. In FIG. 17, the spring is in a contracted state.

One end of the artificial blood vessel, such as a Solcograft, is attached to the patient's vein with several stitches. A device according to the invention containing a spring is then inserted into the graft so that the outer end of the device along with the corresponding end of the spring reaches a position approximately 2 cm inside the vein. The spring is then expanded inside the vascular graft and released from the device. The device is then removed from the vascular graft.

A subcutaneous incision allows the free end of the graft to be routed to the artery opening and attached to the artery.

It has been found that the above device has significant advantages.

1. The graft does not collapse due to spring action when implanted.

2. The connecting conduit, i.e. the artificial blood vessel, can be safely compressed or tightened after removal of the cannula to reduce blood loss, and the conduit immediately returns to its maximum diameter under the action of a spring.

3. It is easy to find the subcutaneous artificial blood vessel, and therefore it is easy to make a hole for the conduit.

4 It was found that the risk of stenosis formation in veins was reduced. When using conventional techniques, the connection site must be changed and relocated at least once a year because of stenosis.

In addition to the applications of the invention as described above, there are other important areas in which the device of the invention can be used. Currently, it is difficult to carry out studies on animals, for example dogs, in which case it is desirable to inject the drug, for example several times a day, in order to study the effects of long-term studies. Such experiments have not been possible to date because, inter alia, the motion is prone to rapid stenosis.

By using the device described above, e.g.
Long-term testing can be performed on dogs with a single permanent connection.

[Brief explanation of drawings]

1 shows a perspective view of a coil spring for use in a device according to the invention; FIG. 2 shows a side view of the coil spring housing the carrier body and shows the spring in an expanded state; FIG. 2 shows the same device as that shown in FIG. 2, but showing the spring in a contracted state; FIGS. 4 to 7 schematically illustrate the principle of removing spring material from a coil spring according to the invention; 8 and 9 show a variant embodiment based on the same principle as that according to FIGS. 4 to 7, and FIG. 10 diagrammatically shows the possible performance of a coil spring under the action of an external force. 11 shows details of a coil spring using a guide device, FIG. 12 shows an enlarged view of the device of FIG. 11, and FIG. 13 shows a detailed view of FIG. 12 cut along the - line. 13A schematically shows a spring with a support member and a fixed guide member, FIG. 13B shows a detail of the embodiment of FIG. 13A, and FIG. 14 shows a spring with a support member and a fixed guide member. 15 shows a detail of another guide element, FIG. 16 shows the guide element according to FIG. 15 as seen from above, and FIG. 17 shows an arrangement of the device according to the invention. FIG. 18 schematically shows a general view of an embodiment of the invention, FIG. 19 shows an enlarged detail of a further embodiment of the device according to the invention, and FIG. 20 shows a side view of the detail shown in FIG. 19, FIG. 21 shows a device according to the invention for applying a porous tissue, and FIG. 22 shows a flat spring material with recesses. 23 shows an embodiment designed as a ladder-like double spring, and FIGS. 24 and 25 show an embodiment using a coil with adjacent windings that can overlap. 26 shows a variant embodiment of the spring of this device, the spring shown has an overload, and FIG. 27 shows the spring covered with a porous tissue. 3 shows another embodiment.

Claims (1)

Claims: 1. A helical spring having a predetermined length and pitch having first and second ends, and expanding the spring from a first state of a predetermined diameter to a second state of a larger diameter; A tube expansion device comprising an expansion means for conversely contracting the spring, the expansion means causing the ends of the spring to be moved relative to each other by mechanical action of the expansion means while maintaining the predetermined length of the spring. 1. A tube expansion device characterized by having a structure in which the number of windings of a spring is decreased in the length direction of the spring and at the same time the pitch of the spring is increased by rotating the spring vertically. 2. One end 38 of the spring 36 is attached to a shaft 42a located centrally inside the spring, and the other end 39 of the spring is connected to a sleeve 42b surrounding the shaft 42a, thereby 2. A device according to claim 1, wherein the diameter of the spring 36 is increased or decreased by mutual relative rotation. 3. Device according to claim 1, in which the spring material 29 has a radially flattened shape when viewed in axial cross section, in order to reduce the risk of the spring collapsing. 4. Radially oriented shoulders 85, 86 in which the transverse portions or transverse members 82 are centrally located to allow adjacent turns of the spring to overlap.
4. A device according to claim 3, comprising: 5 Porous tissue stockings 84 connect helical elements 78, 80 over substantially the entire length of the spring material.
5. The device of claim 4, enclosing ~82 individual windings. 6. Device according to claim 1, comprising a stocking 73 of elastic tissue surrounding the spring, intended to be implanted with the spring. 7. The spring material 78 is provided with a plurality of radially extending recesses 79 between which axial and transverse micro-sections are formed, thereby increasing the elasticity of the spring. Apparatus according to claim 1. 8 The spring consists of a double helical spring extending in the same plane, the helical elements 80, 81 being tangentially distributed and connected by an axially extending transverse member 82. Equipment described in Section. 9. A stocking 83 of porous tissue surrounds the individual turns 80, 81 of the helical element over substantially the entire length of the spring material and extends laterally on the outside of the helical material, thereby forming a helical shape. 9. The apparatus of claim 8, wherein the helical material is overlapped within adjacent turns of material. 10 Spring 90 has a reduced diameter portion at at least one end thereof, so that
Device according to claim 1, which is designed to act as a filter after its application. 11. The device of claim 1, wherein the reduced end 91 of the spring 90 forming the flow path has a distance between turns of about 3 mm. 12 an axially extending elongate member 94 occupying a peripheral portion of the spring and having one end 96 attached to the spring;
2. A device according to claim 1, comprising an elastic stocking 95 surrounding the spring, which is attached to and intended to be implanted with the spring. 13 comprises a cylindrical tubular carrier body 37 disposed inside the coil spring 36, the carrier body 3
7 has a central portion 47 and an end portion 3 of the spring.
end portions 40, 41 rotatable relative to each other at 8, 39, the ends 38, 39 of the spring 36 being connected to the respective end portions 40, 41, further comprising means 42, 43, 44, means 42; ,43,
4. A device as claimed in claim 1, in which the end portions 40, 41 can be rotated relative to each other by means of 44 to expand and contract the spring 36. 14. said means comprises a coaxial member 42 connected to one end portion 41, an inner element 42a of said member;
extends through the carrier body 37 and is connected at its end to the other end portion 40 and is connected to the coaxial member 4
2. Device according to claim 1, in which rotors 43, 44 are arranged at the outer free ends of 2.