JP4417013B2 - Occlusion prevention catheter - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a fluid management apparatus that minimizes the risk of blocking a catheter hole, and more specifically, to a fluid management apparatus having a catheter having a coil portion having a plurality of holes on the inner surface of the coil. .
[0002]
[Prior art]
Cerebral edema is a disease of the nervous system that results from abnormal deposition of cerebrospinal fluid (CSF) within the ventricle or brain cavity. CSF is a colorless and transparent fluid that is made primarily by the choroid plexus and surrounds the brain and spinal cord. CSF constantly circulates through the ventricular system and is eventually absorbed into the bloodstream. CSF helps protect the brain and spinal cord. Since CSF keeps the brain and spinal cord in a floating state, it acts as a protective cushion or “shock absorber” that prevents damage to the central nervous system.
[0003]
Cerebral edema is a disease that affects both children and adults, and occurs when normal drainage of CSF in the brain is hindered for some reason. Such interference is caused by a number of factors including, for example, genetic predisposition, intraventricular or intracranial hemorrhage, infections such as meningitis, head trauma, and the like. When CSF flow is interrupted, an imbalance between the amount of CSF formed by the choroid plexus and the proportion of CSF absorbed into the bloodstream results, increasing the pressure in the brain, Swelling is caused.
[0004]
Cerebral edema is most often treated by surgically inserting a flow diverter that directs CSF flow from the ventricle to other areas of the body where CSF is absorbed as part of the circulatory system. . Shunt devices are sold in various forms and typically share similar functional components. These components include a ventricular catheter that is inserted through a burr hole in the skull and implanted in the patient's ventricle, a drainage catheter that carries the CSF to the final drainage location, and the CSF from the ventricle to the drainage location. Any flow control mechanism that controls unidirectional flow to maintain normal pressure in the ventricle, such as a diversion valve, is included. Ventricular catheters are generally provided along the length of the ventricle catheter and have a number of holes or holes that allow the CSF to flow into the flow diverter. To facilitate catheter insertion, a removable rigid stylet is provided in the lumen of the ventricular catheter and is used to guide the catheter to the desired target location. Alternatively or in addition, a rounded brain cannula and peel-away sheath have been used to assist in catheter placement.
[0005]
[Problems to be solved by the invention]
Although diversion is considered one of the basic neurosurgical procedures, it is most likely to cause complications. The most frequent complication of diversion is obstruction of the diversion device. Occlusion can occur anywhere in the diverter, but most often occurs at the ventricular end of the diverter. There may be several processes leading to the occlusion of the ventricular catheter, but occlusion typically occurs when tissue, such as the choroid plexus, grows around the catheter and within its pores. Ventricular catheter holes can also be blocked by debris, bacteria, or blood clogged inside the catheter hole. In addition, problems with ventricular catheters may occur due to excessive draining of CSF, which causes the ventricular wall to collapse on the catheter and block the holes in the catheter wall, thereby draining the CSF. to disturb.
[0006]
Some of these problems can be handled by backflushing. This backflushing is a method of removing occlusive substances using CSF present in the flow dividing device. However, this method may be useless because of the small size of the ventricular catheter hole and the small amount of wash solution that can be used in the diverter. Other shunting devices are designed to include a mechanism for washing the shunting device. For example, some flow dividing devices include a pump device in the device, and the device is washed by flowing the liquid in the device at a considerable pressure and speed. Even in the backflush method, when the flow dividing device is washed using a built-in mechanism, the blockage may not be released depending on factors such as the size of the hole, the degree of blockage, and the range of the hole.
[0007]
An occluded ventricular catheter can be recovered by cauterizing the catheter to remove the occluded tissue and reopening the existing occluded hole. Alternatively, a new hole may be formed in the catheter. However, even with such a recovery, the obstruction may not be removed from the ventricular catheter depending on the position of the obstructed hole. In addition, depending on the extent of tissue growth in and around the catheter, it may not be possible to form additional holes, for example, in situations where tissue growth covers a significant portion of the ventricular catheter. Sometimes. Another drawback of restoring a blocked ventricular catheter by forming a new hole is that the risk of repeated occlusions cannot be avoided or reduced by this method.
[0008]
Because attempts to wash or recover an obstructed ventricular catheter are often wasted or rendered ineffective, it is often done to treat the occlusion by replacing the catheter. This can be achieved simply by removing the occluded catheter from the ventricle, but the growth of the choroid plexus and other tissues around the catheter and inside the hole impedes removal or replacement of the catheter. There is. Care must be taken to avoid damage to the choroid plexus that can cause serious injury to the patient, such as bleeding. These methods not only present a significant risk of damaging the patient, but can also be very expensive, particularly when shunting of the diversion is a recurring problem.
[0009]
Accordingly, there is a need for a flow diverter that minimizes or eliminates the risk of clogging the catheter hole and reduces the need for repeated repairs and / or replacements.
[0010]
[Means for Solving the Problems]
The present invention overcomes the disadvantages that were unavoidable with prior art fluid management devices by providing an implantable catheter with a coiled end having holes located on opposing surfaces inside the coil. . The fluid management device of the present invention includes a long and substantially cylindrical base, a distal end capable of taking at least one coil shape, and a conduit having a flow path extending between the distal end and the proximal end. According to the present invention, the coil shape at the tip may have one or more turns. When tension is applied to the catheter, the coiled tip is unwound and both the base and tip of the conduit are substantially straight. When the tension is released, the tip becomes the coil shape again. The coils of the catheter are preferably closed together to minimize the growth of the choroid plexus or other tissue at the implantation site into and around the catheter.
[0011]
The fluid enters the conduit flow path through one or more openings, also known as holes in the coiled portion of the conduit tip. At least one hole is disposed on the inner surface of the coil of the catheter of the present invention. Therefore, at least one hole does not exist in the vicinity of the tissue at the implantation site, and is protected from the tissue by winding the coil. In the present invention, the conduit may have almost any number of holes, and the holes may have almost any size and shape.
[0012]
Further features of the invention, its nature and various advantages will be more apparent from the accompanying drawings and the description of the preferred embodiments.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
The implantable fluid management device according to the present invention facilitates fluid removal or fluid flow into the treatment site. As an example, the tip of the device is implanted in the ventricle to drain excess fluid from the ventricle and guide it elsewhere in the patient's body. The fluid management device according to the present invention is advantageous in that the fluid can be discharged while minimizing the possibility that the discharge catheter is blocked.
[0014]
As shown in FIG. 1, the implantable fluid management device 10 includes a catheter 12 having a base 14, a tip 16, and a flow path extending therebetween. The base 14 of the catheter 12 includes a first end (open end) 18, a transition end 20, and a lumen 30 (FIGS. 2A, 3A and 3A) connecting these two ends. 3 (B)). The distal end 16 of the catheter 12 is defined by an outer wall 44 (see FIGS. 4 and 5), and includes a first end (connection end) 22, a second end (front end) 24, It has a lumen 40 (see FIGS. 3B and 4) extending between the two. The distal end 16 of the catheter 12 has at least one fluid inlet 42 (see FIG. 4). The fluid inlet 42 is disposed on the outer wall 44 of the catheter 12 and allows fluid to flow into the lumen 40 of the distal end portion 16. As shown in FIGS. 1 to 3A and 4, the normal shape of the distal end portion 16 of the catheter 12 is a coil shape having a spiral structure of at least one turn. Preferably, the fluid inlet (hole) 42 is located in this spiral or coil inner portion 48 (see FIGS. 4 and 5).
[0015]
In use, at least a portion of the distal end 16 and base 14 of the catheter 12 is implanted in a location within the patient's body where fluid is to be drained, such as the ventricle 26. Then, the fluid is discharged from the ventricle 26, guided to the first end (open end) 18 through the catheter 12, and the fluid is absorbed into the blood flow from the first end (open end) 18. To other parts of the body, such as the peritoneum or heart atrium. The first end (open end) 18 can also be connected to a diversion valve 28 that is effective to regulate the flow of fluid through the implantable fluid management device 10. In other embodiments, the fluid management device 10 may be used to deliver fluids and / or chemicals to a processing site, so that the first end (open end) 18 is fluid and / or Alternatively, it may be connected to a medicine delivery source.
[0016]
The base 14 of the catheter 12 is shown in more detail in FIGS. 2A-3B and may have almost any shape, but is preferably a long, generally cylindrical member. As shown in FIGS. 2A-3B, the base 14 is defined by an outer wall 32 and extends between the first end (open end) 18 and the transition end 20. 30. The first end (open end) 18 of the base 14 is open and communicates with the lumen 30 so that fluid can flow through the base 14. The transition end 20 of the base 14 is attached to the distal end 16 of the catheter 12 as shown in FIGS. 2 (A), 3 (A), and 3 (B).
[0017]
As shown in FIGS. 2B to 3B, the base 14 of the catheter 12 has an outer diameter D.₁Have As used herein, the term “outer diameter D of base 14”₁"Is defined as the distance between any two points located on the outer surface 34 (see Fig. 2B) of the outer wall 32 connected by a straight line passing through the center of the base 14. The lumen 30 of the base 14 has a lumen diameter D as shown in FIG.₂Have As used herein, the term “lumen diameter D of base 14₂"Is defined as the distance between any two points located on the inner surface 36 of the outer wall 32 connected by a straight line passing through the center of the base 14.
[0018]
The base 14 of the catheter 12 may have almost any length, but preferably the length of the base 14 is in the range of about 30 mm to 100 mm. As shown in FIGS. 2A to 3B, the outer diameter D of the base 14 of the catheter 12₁May vary, but outer diameter D₁Is preferably sized in harmony with the target embedding location. More preferably, the outer diameter D of the base 14 of the catheter 12₁Is in the range of about 2 mm to 4 mm. Lumen diameter D of the base 14 of the catheter 12₂May vary, but the lumen diameter D₂Is preferably sufficient to allow fluid flow through the lumen 30 of the base 14. More preferably, the lumen diameter D₂Is in the range of about 0.5 mm to 2 mm.
[0019]
As shown in FIGS. 2 (A) to 3 (B), the distal end portion 16 of the catheter 12 has a first end portion (connection end portion) 22, and the first end portion (connection end). Part) 22 is open, and fluid can flow into the inner cavity 30 of the base 14 so that fluid can flow into and out of the distal end portion 16. . The second end portion (the most distal end portion) 24 of the distal end portion 16 may be opened so as to allow fluid to flow into the lumen 40 of the distal end portion 16. Alternatively, the second end portion (the most distal end portion) 24 may be closed or sealed so that fluid does not flow through the inside. The lumen 40 extending between the first end (connecting end) 22 and the second end (leading end) 24 may have almost any shape, but is preferably shown in FIG. It is almost cylindrical. The lumen 40 of the distal end portion 16 has a lumen diameter D._ThreeHave As used herein, the term “lumen diameter D of tip 16”_Three"Is defined as the distance between any two points located on the inner surface 46 of the outer wall 44 connected by a straight line passing through the center of the lumen 40 of the tip 16.
[0020]
As shown in FIGS. 2A to 4, the distal end portion 16 of the catheter 12 may have almost any shape, but is preferably a long and substantially cylindrical member that forms a helix. It is distorted into a coil shape (pre-formed). The spiral or coil shape of the tip 16 defines a region 45 (see FIG. 5) that is inward with respect to the spiral or coil. Further, the tip end portion 16 has a coil inner surface (inner portion) 48 and a coil outer surface 50 as shown in FIGS. 4 and 5. As used herein, the coil inner surface 48 refers to the surface of the coil that faces the spiral region of the tip 16, i.e., the region 45 that is surrounded by the coil shape. As used herein, the coil outer surface 50 refers to the surface of the coil that faces the outer region 47 (see FIG. 5) opposite the region 45.
[0021]
The helical or coil shape of the distal end 16 of the catheter 12 may have almost any number of turns. As used herein, “winding” refers to one revolution around the coil, ie, one revolution starting from any part of the coil and 360 ° around the central longitudinal axis (L) of the coil. Preferably, the distal end portion 16 of the catheter 12 has one or more turns, more preferably the number of turns is in the range of about 1-10. As an example, which is not intended to be limiting, FIG. 2 (A) illustrates an embodiment with a five turn spiral. The spacing S (see FIG. 4) between adjacent turns of the spiral shape or coil shape may vary, but this spacing S will allow the tissue to grow between adjacent turns of the spiral shape or coil shape. Preferably it is sufficient to prevent. More preferably, the spacing S between adjacent turns is in the range of about 0 mm to 2 mm.
[0022]
As shown in FIG. 3A, FIG. 4 and FIG._FourHave As long as it is used here, the outer diameter D of the spiral shape of the tip 16, that is, the coil shape._FourIs defined as the distance between any two points located on the coil outer face 50 connected by a straight line passing through the central longitudinal axis of the coil shape, ie, the coil shape. A person skilled in the art will know that the outer diameter D of the spiral shape of the tip portion 16, that is, the coil shape._FourIt will be appreciated that the dimensions of can vary depending on the intended application. As an example, a catheter 12 designed for use with infants or children has an outer diameter D of a spiral or coil shape of the tip 16 than a catheter 12 designed for use with an adult._FourIs small. Preferably, the outer diameter D of the spiral shape of the tip portion 16, that is, the coil shape._FourIs the outer diameter D of the base 14₁(Refer to FIG. 2 (B) to FIG. 3 (B)) or the outer diameter D₁4 times or less. More preferably, the outer diameter D of the coil shape_FourIs in the range of about 4 mm to 9 mm. If it is an expert, the outer diameter D of the coil shape of the front-end | tip part 16 will be shown._FourIs the outer diameter D of the base 14₁It will be appreciated that a catheter 12 that is approximately the same as or less than is advantageous for minimizing damage that may occur during implantation of the fluid management device 10.
[0023]
As shown in FIG. 4, the distal end 16 of the catheter 12 further has at least one fluid inlet (hole) 42. The fluid inlet 42 extends through the outer wall 44 of the tip 16 and communicates with the lumen 40 of the tip 16 so that fluid can flow. Preferably, the hole is located on the coil inner surface 48 in a concealed or protected manner by a helical or coil-shaped winding of the tip 16. The coil inner surface 48 may have any number of fluid inlets 42, but the number of fluid inlets 42 located on the coil inner surface 48 is preferably in the range of about 4-40.
[0024]
Those skilled in the art will appreciate that each fluid inlet 42 may have almost any size, shape, or position on the coil inner surface 48. The dimensions of each fluid inlet 42 may vary, but the area of each fluid inlet 42 is approximately 0.05 mm.²To 1mm²It is preferable to be in the range. Each fluid inlet 42 may have almost any shape, such as circular, oval, rectangular, square, or combinations thereof. Each fluid inlet 42 may be disposed almost anywhere on the coil inner surface 48 and the spacing between adjacent fluid inlets 42 may vary. For example, the interval between the fluid inlets 42 may be constant, indefinite, or a combination of both. By way of example, and not by way of limitation, FIG. 4 illustrates equally spaced fluid inlets 42 aligned along the longitudinal axis L of the tip 16 spiral or coil shape.
[0025]
In one embodiment of the present invention, the base 14 and tip 16 of the catheter 12 may be integrally formed. Alternatively, the base portion 14 and the tip portion 16 may be composed of two separate members connected to each other. Various connection techniques known to those skilled in the art may be used to connect the base 14 and tip 16. By way of non-limiting example, the tip 16 may be welded, ultrasonically bonded, glued, or mechanically connected to the base 14 of the catheter 12.
[0026]
The base 14 and tip 16 of the catheter 12 may be formed from any biocompatible material. Preferably, at least the tip 16 of the catheter 12 is a flexible material that is coiled (pre-formed), such as silicone, a silicone-like material, a shape memory material, polyurethane Or a polymer to which barium sulfate is added so that X-ray detection is possible. In some embodiments, at least the distal end 16 of the catheter 12 may be formed of a shape memory material, or at least the distal end 16 of the catheter 12 contains a shape memory material embedded in the outer wall 44. Also good.
[0027]
In use, the distal end portion 16 of the catheter 12 is in the first state (normal state) in the spiral shape, that is, the coil shape shown in FIG. 3 (A), and in the first state shown in FIG. 3 (B). It is possible to deform between the two states (substantially stretched state). The ability of the tip 16 to be able to deform between these two conditions facilitates insertion and effective operation of the catheter 12 at the treatment site. In one embodiment, a catheter 12 containing or formed from a shape memory material, such as polyurethane with shape memory quality, is prepared in a substantially straight or stretched state. 12 is embedded in this state. When the catheter 12 is placed in the presence of an external stimulus, such as body temperature or fluid, the distal end 16 of the catheter 12 is normally placed as shown in FIGS. 2 (A) and 3 (A). The spiral shape, that is, the coil shape.
Alternatively, the catheter 12 has a stylet 60 suitable for providing rigidity to the catheter 12 inserted into the fluid management device 10 through the first end (open end) 18 of the base 14 of the catheter 12. Later, it may be inserted into the patient's body. The stylet 60 can be extended to pass through the base 14 and the distal end 16 of the catheter 12, so that the distal end 16 of the catheter 12 is in a substantially extended state as shown in FIG. . When the catheter 12 is implanted at the treatment site, the stylet 60 is removed. When the stylet 60 is removed, the distal end portion 16 of the catheter 12 again becomes its normal spiral shape, that is, a coil shape (see FIGS. 2A, 3A, and 4).
[0028]
In other embodiments, the catheter 12 may be housed within a sheath (not shown) prior to insertion into the patient's body. This sheath may be, for example, a plastic tube, and is suitable for the distal end portion 16 of the catheter 12 to be in the substantially extended state shown in FIG. This sheath may be placed around the body of the catheter 12 during manufacture of the catheter 12, or the sheath may be manually applied to the body of the catheter 12 at a point prior to insertion. After the catheter 12 is implanted at the treatment site, the sheath may be removed. When the sheath is removed, the distal end portion 16 of the catheter 12 again becomes its normal spiral shape, that is, a coil shape (see FIGS. 2A, 3A, and 4).
[0029]
One skilled in the art will appreciate further features and advantages of the invention based on the above-described embodiments. Accordingly, the invention is not limited to what has been particularly shown and described, except as noted in the claims. All publications and references cited herein are expressly incorporated herein in their entirety by reference.
[0030]
  Specific embodiments of the present invention are as follows.
(A) comprising a catheter, a coiled region, and at least one fluid inlet;
The catheter has a base, a tip, and an outer wall defining a lumen extending between the base and the tip.
The coiled region is formed at the tip, and the coiled region forms at least one spiral.
The at least one fluid inlet is formed in an inner portion of the coiled region, the at least one fluid inlet being in fluid communication with the lumen of the catheter. Fluid management device.
  (1) The lumen of the distal end portion of the catheter has an outer diameter smaller than the outer diameter of the lumen of the base portion of the catheter.Embodiment (A)The device described in 1.
  (2) The outer diameter measured in a direction across the spiral of the coiled region is equal to the outer diameter of the base of the catheter,Embodiment (A)The device described in 1.
  (3) The outer diameter measured in the direction across the spiral of the coiled region is not more than four times the outer diameter of the base of the catheter.Embodiment (A)The device described in 1.
  (4) The outer diameter measured in a direction across the spiral of the coiled region is less than about 10 mm.Embodiment (A)The device described in 1.
  (5) The length of the helix formed in the coiled region of the catheter is in the range of about 30 mm to 100 mm when measured from the first end to the second end.Embodiment (A)The device described in 1.
[0031]
  (6) The device according to embodiment (5), wherein the number of turns of the spiral formed in the coiled region of the catheter is about 1 to 10.
  (7) It further includes a fluid inlet formed at the forefront of the distal end of the catheter and communicating with the lumen of the catheter so that fluid can flow.Embodiment (A)The device described in 1.
  (8) the number of the at least one fluid inlet is in the range of about 1 to 40;Embodiment (A)The device described in 1.
  (9) The shape of the at least one fluid inlet is selected from the group consisting of a circle, an ellipse, and a polygon.Embodiment (A)The device described in 1.
  (10) The catheter has a plurality of fluid inlets, and the fluid inlets have a combination of various shapes.Embodiment (A)The device described in 1.
[0032]
  (11) The area of the at least one fluid inlet is about 0.05 mm.² To 1mm² In the range ofEmbodiment (A)The device described in 1.
  (12) The catheter has a plurality of fluid inlets, and the fluid inlets have a combination of various shapes.Embodiment (A)The device described in 1.
  (13) The coiled region of the distal end portion of the catheter is formed of a flexible material, and the spiral disappears when tension is applied, but when the tension is released, the coil returns at least once.Embodiment (A)The device described in 1.
  (14) The coiled region of the catheter is selected from the group consisting of silicone, materials similar to silicone, shape memory materials, polyurethane, and polymers doped with barium sulfate. The device according to embodiment (13), wherein the device is formed from a material.
  (15) The embodiment of claim (14), wherein at least a portion of the tip of the catheter is formed from a shape memory material, and when exposed to an external stimulus, the tip forms a spiral with at least one turn. apparatus.
[0033]
  (16) At least a part of the outer wall of the distal end portion of the catheter contains a shape memory material therein, and when exposed to an external stimulus, the distal end portion forms a spiral having at least one turn. An apparatus according to embodiment (14).
  (17) The distal end portion and the base portion of the catheter are formed of separate members of the catheter, and the distal end portion is welded, ultrasonically bonded, adhered with an adhesive, or mechanically connected to the base portion. Connected by a technology selected from the group consisting of:Embodiment (A)The device described in 1.
[0034]
【The invention's effect】
As described above, according to the present invention, the risk of blocking the catheter hole can be minimized or eliminated, and the need for repeated repairs and / or replacements can be reduced. it can.
[Brief description of the drawings]
FIG. 1 is a translucent perspective view showing a fluid management device according to the present invention embedded in an object.
2A is a perspective view of a catheter of the fluid management device of FIG. 1 according to one embodiment of the present invention. FIG. (B) is an expanded sectional view of the distal end portion of the catheter viewed along line 2B-2B in (A).
3A is a perspective view of a catheter of the fluid management device of FIG. 1 according to another embodiment of the present invention. FIG. (B) is a perspective view of the catheter of (A) according to the present invention in which a rigid stylet is inserted.
4 is an enlarged cross-sectional view of the distal end portion of the catheter as viewed along line 4-4 in FIG. 3 (A). FIG.
5 is an enlarged cross-sectional view of the distal end portion of the catheter as viewed along line 5-5 in FIG.
[Explanation of symbols]
10 Implantable fluid management device
12 Catheter
14 base
16 Tip
18 First end (open end)
20 Transition end
22 First end (connection end)
24 Second end (leading edge)
26 ventricle
28 Diverging valve
30 lumens
32 Exterior wall
34 Exterior
36 Inside
40 lumens
42 Fluid inlet
44 Exterior wall
45 areas
46 Inside
47 Outer area
48 Coil inner surface (inner part)
50 Coil outer surface
60 Stylet

Claims (15)

Comprising a catheter, a coiled region, and at least one fluid inlet;
The catheter has a base, a tip, and an outer wall defining a lumen extending between the base and the tip.
The coiled region is formed at the tip, and the coiled region forms at least one spiral.
The at least one fluid inlet is formed in an inner portion of the coiled region, the at least one fluid inlet is in fluid communication with the lumen of the catheter;
An implantable fluid management device, wherein an outer diameter measured in a direction across the spiral of the coiled region is equal to or smaller than the outer diameter of the base of the catheter. The apparatus of claim 1 , wherein an outer diameter measured in a direction across the spiral of the coiled region is less than 10 mm. The length of the helix formed in the coil-shaped region of the catheter is measured from the first end to the second end, it is in the range of 30mm to 100 mm, according to claim 1 or 2 apparatus. The apparatus according to claim 3 , wherein the number of turns of the spiral formed in the coiled region of the catheter is 1 to 10. The apparatus according to any one of claims 1 to 4 , further comprising a fluid inlet formed at the forefront of the tip of the catheter and in fluid communication with the lumen of the catheter. The apparatus according to any one of claims 1 to 5 , wherein the number of the at least one fluid inlet is in the range of 1 to 40. The apparatus according to any one of claims 1 to 6 , wherein the shape of the at least one fluid inlet is selected from the group consisting of a circle, an ellipse and a polygon. The apparatus according to any one of claims 1 to 7 , wherein the catheter has a plurality of fluid inlets, the fluid inlets having a combination of various shapes. It said at least one fluid inlet area is in the range of 0.05 mm ² to 1 mm ^2, according to any one of claims 1 to 8. The catheter has a plurality of fluid inlets, the fluid inlet comprises a combination of various shapes, according to any one of claims 1-9. The coiled region of the tip of the catheter is formed from a flexible material, but the helical disappears by the application of tension, the coil is returned at least one turn when releasing the tension of claims 1 to 10 The device according to any one of the above. The coiled region of the catheter is formed from a flexible material selected from the group consisting of silicone, silicone-like materials, shape memory materials, polyurethane, and polymers doped with barium sulfate. Item 12. The apparatus according to Item 11 . 13. The device of claim 12 , wherein at least a portion of the tip of the catheter is formed from a shape memory material, and the tip forms a spiral with at least one turn when exposed to an external stimulus. At least a portion of the outer wall of the tip portion of the catheter is contained a shape memory material inside the distal end portion when exposed to external stimulation forms a spiral having at least one turn, claim 12 The device described in 1.   The distal end portion and the base portion of the catheter are made of separate members of the catheter, and the distal end portion is made of a group consisting of welding, ultrasonic bonding, adhesion with an adhesive, or mechanical connection to the base portion. The apparatus of claim 1 connected by a selected technique.

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