DE19964093B4 - A sling for use with a catheter for retrieving debris from vessels or body cavities - Google Patents

Abstract

A sling for use with a catheter for retrieving debris from vessels or body cavities having an elongated proximal portion (1) and a distal portion (2) in the form of a sling, wherein
the elongated proximal section (1) merges into the distal section (2),
the loop consists of a flexible superelastic material with shape memory,
the distal portion (2) in the fully unfolded state in side view a semicircle ( 1 ) and in plan view assumes a circular to transverse oval shape,
the largest diameter of the transverse oval shape extends transversely to the imaginary axis of the proximal section (1) ( 8a -c)
and wherein, depending on how far the sling is pushed out of the catheter, a variable looping diameter is achieved up to the maximum diameter.

Description

The The present invention relates to a fishing loop in a new particular Shape, with variable diameter, with the foreign body out the human body can be removed again.

at interventional therapy of vascular malformations and others Hollow organs or organ can Parts of catheters or guidewires accidentally be separated. In the interventional closure of vascular shunt connections with Embolisaten can accidentally placed in an inappropriate place or by the blood flow taken to other vessels be there and unintentionally vessels there close.

Also in interventional therapy to keep open coronary stenoses By balloon dilatation of endoprostheses (stents), these can when pushing forward from the balloon or during dilatation unfold only imperfectly. A stay of these misplaced or imperfectly unfolded prostheses can lead to immediate vascular occlusion the consequence of a life-threatening acute myocardial infarction.

After this first only the possibility Surgical removal of foreign bodies were the same since 1954 also from the vascular system with various gripping tools, such as stone extraction baskets, hooks, Removed biopsy forceps or wire loops.

An advancement of the simple wire loop represents in the US 5,171,233 A and J. Yedlicka et al. This snare consists proximally of a straight stem and a round or oval loop of "shape memory" elastic material. The distal loop-shaped part has a rigid angle to the shaft of preferably 90 °. The disadvantage of this sling is that its catching cross-section is limited and with it only foreign body can be optimally detected, which are approximately parallel to its proximal end and thus parallel to the catheter through which the sling is inserted. Also, the delivery catheter is often on the side of the vessel wall, which in a loop formation adversely affects the capture of a guidewire by extended capture times and extended X-ray fluoroscopy times. If the loop diameter chosen is too large, this loop can not unfold in a small vessel, which is a great disadvantage especially in the risk of salvaging stents in the narrow coronary arteries, and if the diameter chosen is too small, the foreign body can not be grasped.

In the patent DE 195 14 534 C2 a loop with variable opening angle is described. This has the disadvantage that it unfolds only after pushing far out of the catheter to the maximum cross-sectional area for trapping debris. However, this much space is not available in all vessel situations.

Of the The present invention is therefore based on the problem of an interventional Instrument with a variable loop size to create, with the foreign body in different positions from body vessels too with smaller diameter, as in coronary arteries and others Body cavities easily can be recovered and does not have the disadvantages of the previously known instruments.

The Problem is solved by a catching loop with the features of claim 1.

By different pushing out of the catch loop from the catheter can have a variable loop diameter up to the maximum diameter be achieved.

preferred embodiments The present invention is described in the subclaims.

The Instrument according to the invention preferably consists of a wire in the distal part of a Sling forms and its ends in the proximal part of the shaft run parallel. The parallel pieces of wire can in proximal section be interconnected to displacements of the wire ends against each other to avoid and to increase the stiffness.

The Connection can, for example, with an adhesive or by a Twisting of the two wire ends done. The two pieces of wire of the proximal section can but also each with a friction-reducing hydrophilic layer, z. B. Teflon, or provided with a shrink tube made of Teflon be targeted to the two wire ends each independently to be able to move.

By moving the wire ends against each other, the shape of the loop is changed, and the catch cross section can be increased. Of the Wire may have a variable diameter; For example, the wire of the proximal section may be made thicker to increase torsional stiffness, while the loop may be thinner and thus more flexible and atraumatic.

At the transition in the distal part the pieces of wire run apart and form the noose. If you think of the distal one section not bent, but lying in one plane, so is the noose preferably either approximate circular or transversely oval with the larger diameter, transverse to the imaginary axis of the shaft.

Essential for the Invention, however, is that in the Side view of the loop describes a semi-circular shape. That's how it works depending on the length the pushed out proximal part of the loop a different small or big Forming a sling, which is especially useful in maneuvers of Stents in small vessels like a great one to the coronary arteries Advantage is.

The Sling is preferably made of a contiguous corresponding piece of wire. It is advantageous if the distal section has a small blunt nose to introduce the to facilitate collapsed loop in the catheter.

In another embodiment The loop can also be formed from two correspondingly shaped wires which are connected at their top. The wire ends can For example, be connected by a socket, in by soldering, Welding, Gluing or beading be held. To avoid vascular injury is the socket rounded at its distal end. The rounding can except by Loops also z. B. by a clamped, -welded or soldered mushroom-shaped Rotary part can be achieved. The two wires can be at their distal end also be soldered or welded into a small atraumatic ball. At the same time, the sphere serves as an orientation aid in fluoroscopy.

It is particularly advantageous if the sling is not a simple one Wire but from a wrapped wire strand or a wrapped wire consists.

The Using a strand of wire reduces the risk of perforation due to its greater flexibility the snare tip when pushing out of the catheter. Also is When a wire fiber breaks, the functionality of the loop is not impaired. The noose may also be a combination of one or more Be built wire cores or one or more wire strands.

It It is also possible to use a variable diameter wire for the sling. It is particularly advantageous, the loop in the nose area of the snare head to stiffen and to choose the nose angle dull, so that the sling already at Pushing out of the catheter even at small radii an approximately circular loop forms. This stiffening can according to the invention by introducing a Spring element in the form of a short, second piece of wire or take a strand. This spring element can in addition to the usual circular Cross section also has a cross section in the form of a rectangle or an oval and, for example, conical on both sides rejuvenate. A rectangular profile has the advantage that the rigidity is mainly in one level up becomes.

The Distal, the loop-forming section can be made any flexible superelastic material which allows the loop to exit from the catheter returns to its original shape. suitable Materials for this are for example steels with spring properties, such as surgical steel, or Co-Cr-Mo alloys. However, particularly suitable are Ni-Ti alloys with shape memory, for example nitinol. With Nitinol the form of the noose can pass through a suitable heat treatment imprinted become.

to increase the radiopacity Can the sling in addition be coated with gold or platinum, or with a gold or Be wound around platinum or tungsten wire, and also the tungsten wire can be gold plated. The radiopaque Wire can also be woven into the wire strand.

Even though It is easiest in terms of production technology, the loop and the Shaft made of a continuous wire or a strand can also both cuts be made of different materials, based on several materials Way can be connected. So, for example a loop of a flexible super-elastic material a jack with a common one Core wire that is not made of a super elastic Material must exist. The Connection of the flexible loop made of a super-elastic material with a common core wire through a socket can by soldering, Gluing, welding or terminals. In another embodiment, the snare wire or the strand only on one length from 5 to 20 cm braided around the distal conically tapered core wire be and with a shrink tube made of, for example Teflon through a warming force fit get connected.

The proximal section can also only from a normal or teflonized wire helix to or sheathed to hold the pieces of wire of the proximal section together and reduce friction when passing through the catheter. The friction reduction can also be achieved by teflonizing the shaft or by coating with a hydrophilic sliding layer.

At the proximal end of the shaft, a Torquer can be screwed on. With that you can on the one hand the wire ends are held together and on the other hand The instrument can be advanced through the catheter and with the help of The torquers are easily rotated and moved to catch a foreign body.

The Instrument according to the invention preferably has a length from the distal to the proximal end of 20 cm up to 450 cm, wherein the oval transverse diameter of the loop has a value of 2 to 150 mm can have. The diameter of the snare wire, or the wire strand is usually at least 0.05 mm and a maximum of 0.5 mm.

Around a foreign body out of the body to remove, the instrument of the present invention is like follows applied: First, a catheter is up to the desired location introduced. When the distal end of the catheter is in front of the foreign body to be rescued, The distal folded end is preceded by the nose in the Catheter introduced and pushed through to the distal side of the catheter Loop comes out again. Depending on how far they pushed out is, are formed differently sized capture cross sections. The displacement of the instrument through the catheter is preferably carried out with a Torquer or a handle, which at the proximal end of the Schlingenschafts is fixed.

In the phase B can already during the pushing out of the half "folded" loop length the catheter has a smaller loop with a diameter about half the diameter be formed, as in phase A, when the loop unfolds completely is.

By different pushing out of the folded loop can be any number of intermediate sizes of the loop diameter between the phase A and B generate, which is a significant advantage compared to US 5,171,233 A each having only a fixed diameter and a right angle loop angle, which is a serious drawback when retrieving coronary stents in narrow vessels having previously not exactly measurable vessel diameters. So z. B. unfolded at a too large loop diameter, the stretched loop with the risk of vascular injury. If the loop diameter chosen is too small, for example, the stent which is not or only partly expanded may not be securely gripped and thus not recovered. These disadvantages, the inventively proposed loop does not have.

The Variation of the loop diameter allows foreign matter in Vessels with Different diameters are optimally taken and recovered can.

With The instrument according to the invention may foreign matter from Vessels and Salvaged body cavities become. In particular, it is suitable for the removal of foreign bodies, especially of Stents, vessels, urinary tract and bile and respiratory tracts and the gastrointestinal tract or for use in laparoscopic surgery.

The Invention will now be further illustrated with reference to some figures become.

1 is a side view of an instrument according to the invention with a Torquer in a catheter in phase A.

2 is a view of the instrument 1 from the front.

3 is a view of the instrument 1 from above.

4 is a side view of an instrument according to the invention with a Torquer in a catheter in phase B.

5 is a view of the instrument 4 from the front.

6 is a view of the instrument 4 from above.

7 shows an enlarged section in the nose area of 2 ,

8a - 8c show an embodiment of the instrument, which is formed of a continuous wire.

9a - 9c show an embodiment of the instrument with a proximal portion of a core wire with spiral helix.

The in the 1 to 6 reproduced embodiment of the instrument according to the invention consists of a bent wire 3 whose ends 9 parallel and the proximal section 1 form. In the distal section 2 forms the wire 3 a noose 2 ,

The pictures show the instrument in a catheter 8th , A nose 4 at the top of the distal section 2 facilitates the folding of the loop 2 and insertion into the catheter 8th ,

The 1 to 3 show the instrument according to the invention in a catheter 8th in phase A, ie with fully worn loop 2 with maximum diameter of the catch loop.

The 4 to 6 show the instrument according to the invention in a catheter 8th in phase B, ie with only partially worn loop 2 with a smaller diameter of the catch loop.

With a goal cross 7 The instrument can be relative to the catheter 8th be moved and thus different sized loop diameter can be formed, as in 3 and 6 is illustrated.

In 7 becomes an inventive embodiment of the catching loop with an enlarged section of the distal part 2 the noose of 2 shown. With an additional spring element 5 , For example, from a piece of wire with both ends conically tapered wire ends, the formation of the nose shape of the wire 3 and thus the opening of the catheter 8th folded loop 2 after leaving the catheter 8th significantly supported.

To improve the radiopacity, the distal section is 2 the noose 2 with a wire coil 6 wrapped in radiopaque metal.

8a to c represent three views (from the side, from the front and from above) of a possible manufacturing form of the invention, in which the instrument in the proximal part 1 and in the distal part 2 from a single continuous wire 3 is made. To more spring tension to unfold the loop 2 in the nose area 4 To obtain, the loop has a distance between the two proximal sections 1 on, like in 8b visible and a U-shaped shape of the distal portion 2 , as in 8c becomes apparent.

9a to c show three views of a further embodiment of the invention in which the loop 2 from a flexible super elastic wire 3 with a shaped nose 4 at its distal end and the proximal section 1 from an ordinary core wire 11 is formed with a wire helix. The loop 2 is with the possibly conical core wire 11 through a socket 10 connected by soldering, welding, gluing or clamping.

1

proximal section

2

distal Section, loop

3

wire

4

nose

5

spring element

6

wire helix

7

Torque Device

8th

catheter

9

wire ends

10

Rifle

11

core wire with spiral helix

Claims (17)

A sling for use with a catheter for retrieving debris from vessels or body cavities with an elongate proximal portion ( 1 ) and a distal portion ( 2 ) in the form of a sling, wherein the elongate proximal portion ( 1 ) into the distal section ( 2 ), the loop consists of a flexible super elastic material with shape memory, the distal part ( 2 ) in fully unfolded state in side view a semicircle ( 1 ) and in plan view assumes a circular to transverse oval shape, the largest diameter of the transverse oval shape transverse to the imaginary axis of the proximal portion ( 1 ) runs ( 8a C) and, depending on how far the sling is pushed out of the catheter, a variable looping diameter is achieved up to the maximum diameter. A sling according to claim 1, characterized that the noose is formed from a wire or a strand of wire is. A sling according to claim 1 or 2, characterized in that the sling at its distal end the shape of a nose ( 4 ) having. A sling according to claim 3, characterized in that the sling at its distal end in the region of the nose with a spring element ( 5 ) is stiffened. Catching sling according to claim 4, characterized in that the spring element ( 5 ) has a rectangular, square, round, oval or semicircular shape. A sling according to claim 5, characterized in that the spring element ( 5 ) consists of a strand. Catching loop according to one of claims 4 to 6, characterized in that the spring element ( 5 ) is conically tapered at both ends. A sling according to claim 3, characterized in that the sling consists of two wires which, at their distal end, the nose ( 4 ), held together by a socket with a rounded end or a ball. Catching sling according to one of claims 1 to 8, characterized in that the proximal portion ( 1 ) is surrounded by a spiral helix. Catching sling according to one of claims 1 to 8, characterized in that the proximal portion ( 1 ) has a friction-reducing sheathing. Catching sling according to one of claims 1 to 10, characterized in that the superelastic material is a Nickel-titanium alloy is. Catching sling according to one of claims 1 to 11, characterized in that the loop with gold or platinum coated and / or one or more radiopaque threads Gold, platinum, tungsten or gold-plated tungsten or with a wire coil of one of these metals is wrapped. Catching sling according to one of claims 1 to 12, characterized in that it comprises a wire which forms the loop in the distal section and whose parallel ends ( 9 . 8b ) the proximal section ( 1 ) train. Catching loop according to one of claims 2 to 13, characterized in that the wire has a variable diameter Has. Catching sling according to one of claims 1 to 14, characterized in that the loop of a combination one or more wire cores and one or more wire strands consists. Catching loop according to one of claims 2 to 15, characterized in that the wire has a round, oval, semicircular or rectangular cross-section. Catching sling according to one of claims 2 to 16, characterized in that the wire at the distal end of the proximal portion ( 1 ) is conically tapered.