CN1859941B - Guidewire with curved segment - Google Patents

Abstract

A guidewire is shown and described that includes a continuous, unitary guidewire having a first segment, a second segment, and a third segment. The third segment has a bending moment of inertia that is less than the bending moment of inertia of the first and second segments. The guidewire can be used to advance a medical device in a body lumen.

Description

guide wire with curved section

This patent application is incorporated by reference into U.S. Patent Application No. 10/409,270, filed April 8, 2003, entitled "Guidewire Structure for Insertion into an Tracked medical device and method of use" US Patent Application 10/406,020.

technical field

The present invention generally relates to a guidewire structure. In one embodiment, the present invention relates to a guidewire structure capable of being inserted into an interior space of a human or animal body, such as a patient's gastrointestinal (GI) tract.

Background technique

Physicians typically use long, flexible endoscopes to access and view tissue within a patient's gastrointestinal (GI) tract. For the upper GI, doctors may insert a gastroscope into a sedated patient's mouth to examine and treat tissue in the esophagus, stomach, and proximal duodenum. For the lower GI, doctors may insert a colonoscope through the anus of a sedated patient to examine the rectum and colon. Some endoscopes have a working channel, typically about 2.5-3.5 mm in diameter, that extends from a port on the handpiece to the distal tip of the flexible shaft. A physician may insert a medical instrument into the working channel to aid in the diagnosis or treatment of tissue in the patient's body. Physicians typically use flexible biopsy forceps to obtain tissue biopsy samples from the mucosal layer of the GI tract through the working channel of the endoscope.

Insertion of a flexible endoscope, especially into the colon, can be a very time-consuming and uncomfortable procedure for the patient, even when sedated with medication. It often takes several minutes for the physician to advance the flexible endoscope through the spiraling, descending, transverse and ascending portions of the colon. Physicians can diagnose and/or treat tissue within the colon during insertion or removal of the endoscope. A flexible endoscope may "loop" in the colon (eg, in the sigmoid colon or at the splenic flexure of the colon), making it difficult to advance the endoscope further along the colon. As the "loop" forms, the force applied to push the speculum stretches the mesentery and causes pain to the patient. Depending on the patient's anatomy and the skill level of the physician operating the flexible endoscope, some parts of the colon may not be examined, increasing the risk of undiagnosed disease.

Guidewires have been used to aid in the introduction of catheters and other instruments into many parts of the body. Many medical applications and specialized designs of guidewires have been used for cardiovascular use. However, as opposed to the vasculature, there are specific challenges related to the use of guidewires in the GI tract. Because the intestine is more tortuous, soft and usually has a larger diameter. Also, in the case of the small intestine and colon, they are longer than most arteries or veins.

Contents of the invention

In one embodiment, the present invention provides a guidewire structure for use with a medical device inserted into a body cavity, such as the GI tract. The guidewire structure includes a continuous integral guidewire at least including a first section, a second section and a third section disposed between the first and second sections. The bending moment of inertia of the third segment is smaller than that of the first segment and smaller than that of the second segment. The third segment can provide a flexible hinge for bending the integral guidewire. The phrase "continuous integral guidewire" means that the portion of the guidewire associated with the third segment and adjacent portions of the first and second segments does not include any joints, joints, or other connecting parts (such as welds, brass joints, or soldered joint), although the end of the guidewire may include a joint or connecting portion for attaching the guidewire to a handle or for other purposes. In one embodiment, the guidewire is made of only one material, such as a superelastic material. One suitable material that can be used to make the guide wire is Nitinol.

In one embodiment, the cross-sectional area of the third segment is less than the cross-sectional area of the first and second segments. The reduced cross-sectional area of the third section may be formed by grinding the outer diameter of the guidewire, thereby forming a first section of reduced cross-sectional area between the first and second sections of substantially constant cross-sectional area. Three sections. The guidewire may have a circular cross-section, or alternatively may have a non-circular cross-section. A generally tapered transition section may extend from each end of the third section to connect the third section with the first and second sections.

Description of drawings

The present invention is further described below with reference to the accompanying drawings, in which:

Figure 1a shows one embodiment of a guidewire structure as disclosed in U.S. Patent Application 10/409,270;

Figure 1b shows the structure of Figure 1a when one of the guidewires is advanced to the right and the other guidewire does not;

Figure 1c shows the structure of Figure 1a after advancing one guidewire further to the right;

Figure 2 shows an embodiment of the pattern of markers provided on the guide wire to indicate their relative positions to the physician;

Figures 3a to 3c show a guidewire structure advanced in the colon;

Figure 4 schematically shows the handle used to control the movement of the guide wire;

Figures 5a and 5b show successive stages in use of a guidewire structure in combination with a bias tube;

Figures 6a and 6b show successive stages of achieving coaptation between two guidewires using a cutting catheter;

Figure 7 shows two guidewire structures arranged in parallel;

Figures 8a to 8c schematically illustrate the use of guidewire structures with pivoting joint sections;

Figure 9 shows another guidewire configuration described in US application 10/409,270;

Figure 10 shows an embodiment of the invention in which the guidewire cross-section varies along the guidewire length so as to have a reduced cross-section at a location spaced from the end of the guidewire, such as at or proximate to the midpoint of the guidewire length. cross section;

Figure 11 illustrates bending the guidewire shown in Figure 10 into a generally U-shaped configuration for entry into a lumen such as the GI tract;

Figures 12a, b and c show alternative embodiments using different cross-sections;

Figure 13 shows an embodiment of the guidewire of the present invention wherein the guidewire is advanced from the distal end of the medical device to form a loop in front of the distal end of the medical device.

Detailed ways

Figures 1 through 9 show the guidewire structure disclosed in US Patent Application 10/409,270, which is hereby incorporated by reference. Figures 10 to 13 show guidewire structures according to the present invention.

The structure of FIG. 1 a includes a first guide wire 1 and a second guide wire 2 , and the guide wires 1 , 2 are connected to each other by a joint 3 formed at the front end of the guide wires 1 , 2 . Although the joint 3 is shown at the front end, it could alternatively be close to said front end. The joint need not be longer than necessary to securely hold the front ends together side-by-side. Depending on the nature of the joint, lengths as small as 5-10 mm may be sufficient, although greater lengths are sometimes preferred.

The guide wires 1, 2 may be made of materials conventionally used for guide wires, such as straight stainless steel wires, coiled stainless steel wires, glass fibres, plastic materials or nitinol. Typically, the guidewire has a soft tip, ie, a tip portion, having a length of 4-5 cm, which is more flexible than the rest of the guidewire in order to reduce the impact of the tip of the guidewire on which it is passing. risk of injury to the walls of the cavity. When two such conventional guidewires are joined together to form the guidewire structure in Figure 1, it is of course the soft ends, or parts thereof, that are joined together. The length of the joint may be less than the length of the soft end such that a length of soft material remains unaffected by the joint.

All or part of each guidewire can be coated to reduce its coefficient of friction, as is done for conventional guidewires. For example, the guidewire may be coated with a low friction material such as silicone, or with a hydrophilic material that becomes slippery when used in a patient, or both. material and a hydrophilic material applied to the low friction material.

Joint 3 may be formed in any desired manner as long as the leading end of the resulting guidewire structure does not damage the walls of the GI tract or other body cavity and does not cause undue pain when contacting said walls. For example, the joint can be made by gluing or welding the front end parts together and then covering these parts with heat shrink tubing. Alternatively, the ends are held together by a metal strap crimped over the ends (where the metal strap may optionally be wrapped by a casing made of a softer material).

It is not necessary for all guidewires, or both guidewires as the case may be, to consist of materials that are generally regarded as guidewire materials. For example, where the guidewire structure consists of only two guidewires, one of the guidewires may be made of a wire that is connected to the other guidewire by being tied to the other guidewire .

Yet another possibility is to start with a single guidewire that is twice as long as needed, and fold this single guidewire back sharply in half, for example by crimping the folded wire close to the fold, so that it effectively Become a pair of guidewires connected at the fold. A wire structure with an even number of n wires greater than 2 can be obtained by folding the wires by half the number of said numbers.

The working principle of the guidewire structure can be understood by comparing Figures 1b and 1c with Figure 1a. Figure 1b shows the result obtained by advancing the guidewire 1 to the right as indicated by the arrow while keeping the other guidewire 2 stationary. As shown in Figure 1b, this results in the distal region of the guidewire structure bending in one direction such that the advancing guidewire 1 is outside the bend and the stationary guidewire 2 is inside the bend . The guide wire 1 continues to advance beyond the position shown in FIG. 1 b while continuing to hold the guide wire 2 immobile, resulting in the formation of a loop in the end region of the guide wire 1 . This is shown in FIG. 1 c , where the loop is denoted by reference numeral 4 .

In order to enable the doctor to easily advance one of the guide wires while keeping the other stationary, the guide wires are housed in a handle at their ends remote from the joint 3, when advancing the guide wires and When retracted, the handle can move the guidewire up and down. The handle should allow precise adjustment of the relative lengths of the two guidewires. It should also allow the introduction of the various catheters, imagers and other auxiliary equipment discussed in detail below, giving precise information about their relationship to the joint 3 . The handle may have a reversible electric drive enabling the two guidewires to be driven. The motorized drive itself may provide data to enable the user to monitor the length of guidewire that has been advanced.

An example of a handle is shown in FIG. 4 . The illustrated handle 40 comprises a pistol grip 41 in which are mounted a pair of electric motors 42 (one of which is shown) powered by batteries 43 or mains 44 . The motors are controlled by respective finger controls 45, one for each motor, and each control has a forward position, a reverse position and a stop position. Each motor provides drive via a corresponding gear (schematically indicated by reference numeral 46) to a corresponding belt or chain drive 47, each of which drives a corresponding guidewire 48 forward (or backward) . A switch 47a is provided to move the belt or chain away from the guide wire, allowing the guide wire to be unwinded eg at the end of the procedure. A locking mechanism 49 is provided to secure the handle 40 to the catheter or to the receiving channel of the endoscope through which the guide wire is driven. The guidewires may be stored in crimped plastic tubes 50, either two guidewires side by side in a single tube or each guidewire in a separate tube. This has the advantage of keeping the wires clean and avoiding the danger of them being dragged across the floor. In some cases this storage facility can be omitted.

The combined effect of the forms of action shown in Figures 1b and 1c enables the guidewire configuration to be performed in a very advantageous manner. Thus, causing the structure to bend as shown in Figure Ib enables the physician to maneuver the front end of the structure around the bend in the lumen through which the structure is being advanced. As shown in Figure 1c, the ability to form loops allows the guidewire structure to adopt a configuration in which it can be safely advanced along the lumen without excessive strain on the patient. discomfort.

In addition, the presence of the loop at the front of the construct rather than at the end of a single guidewire makes it easier for the construct to follow the main course of the lumen and is less likely to accidentally enter a branch that deviates from the main course . Thus, in the case of the bowel, the tendency to enter, for example, a diverticulum or the ostium of the appendix will be greatly reduced. However, the fact that the loops are not permanent and can be eliminated by arranging the structure in the configuration shown in Figure 1a means that the structure can easily be passed along very narrow channels, and Will not cause damage to itself. Thus, it can, for example, be passed along the channel of an endoscope or down a catheter, as will be explained further below. Also, when the guidewire structure is not in the endoscope or catheter, but directly along the lumen of the patient when doing so, it is not always required to have a loop in front when advancing (eg when it has to go through a small opening) . In such a situation, the guidewire structure is allowed to return to the straight form as shown in Figure Ia, and the two guidewires are advanced in alignment and in unison.

3a-3c schematically show, by way of example, successive stages in advancing the guidewire structure of the invention along the colon 30. FIG. The guidewire structure is shown being introduced in conjunction with a catheter 31 in which the entire guidewire structure is slidably housed. The individual guidewires are represented by _w1 and _w2 . Advances are made by alternately doing the following:

(a) advancing one guidewire while holding the other guidewire stationary; and

(b) Pushing the catheter forward as far as the position shown in Figure 3c, or even a little further.

It would be desirable to avoid, or at least reduce, the use of X-ray imaging to monitor what is happening during endoscopy. With this in mind, each guidewire is preferably provided with a pattern of markers distributed along the length of the guidewire to indicate how far each individual guidewire has been inserted. One such pattern is shown in Figure 2. As shown in the figure, a barcode-like marking pattern of a given color is spaced along a first length (L ₁ ) and then repeated along successive lengths (only L ₂ is shown), with each repetition having a different s color. Each of said lengths may suitably be around 10 cm. This provides a means by which the doctor can easily see which wire has been advanced farther and by how much, and enables him, for example, to equalize the lengths inserted and thereby eliminate any bends (Fig. 1b) or rings (Fig. 1c). Of course, many other indicia patterns, such as numbers or letters, could be used instead of the patterns shown in the figures which are given by way of example only.

Additionally or alternatively, the guidewire structure may be provided with other forms of position indication. It is known to provide a conventional guidewire with a series of miniature conductive coils surrounding the guidewire and spaced along its length, the coils being connected to a current source whereby each coil becomes miniature electromagnet. Such coils may be provided on a guidewire used to form the guidewire structure shown. A detection device outside the patient's body is used to detect the position of the coil inside the patient and thereby determine the position of the guide wire.

The path of the guide wire structure can be influenced by the use of a catheter which can accommodate either or both of the two guide wires when there are exactly two guide wires, and when more than two guide wires are present, One, some or all of the guidewires may be placed. In one embodiment, the catheter has a curved end that allows the application of torque to bias the forward movement of the one or more guidewires, thereby imparting the guidewires in any given direction. The use of a catheter in this manner is shown in Figures 5a and 5b. Figures 5a and 5b show a pair of guidewires 51 and 52 connected at joint 53. The guide wire 51 is received in a catheter 54, referred to herein as a bias tube, such that the front end portion of the bias tube is formed, ie has a curvature thereon. Both guidewire 51 and guidewire 52 with bias tubes are housed in outer catheter 55 . The ends of the catheters 51 , 52 remote from their ends emerge from the catheter 55 to allow their selective advancement and retraction. The end of the bias tube 54 remote from its bent end emerges from the outer conduit 55 at the user's end. By comparing the state shown in Figure 5a with the subsequent state shown in Figure 5b when advancing both guidewires, but advancing guidewire 51 more than the guidewires, the bias tube helps ensure that The combined wire structure bends in the desired direction. If it is desired to cause the structure to advance in other directions, this can be achieved by twisting the catheter 55 about its longitudinal axis, thereby changing the position of the guidewires relative to the lumen through which they are being advanced.

As its name indicates, the purpose of a guidewire is to act as a guide for some other element. Thus, when the guidewire structure is in place, some other element is then passed through it, or pushed or advanced along the guidewire.

As in the case of a catheter used to affect the path of a guidewire structure during passage of a guidewire structure along the lumen, when there are exactly two guidewires, the subsequently introduced catheter may pass between the two guidewires One or two of the guide wires, when there are more than two guide wires, may pass through one, some or all of the guide wires. As the catheter passes over both or all guide wires, once the tip of the catheter reaches the tip of the wire structure, the tip of the catheter will freely protrude beyond the tip of the wire structure, as the case may be. If the catheter does not pass over two or both guidewires, for example if the catheter passes only one of two interconnecting guidewires, the tip of the catheter will generally not be able to protrude beyond the connection between the guidewires. This may be desirable in order to ensure that the leading end of the catheter can be brought to a position pre-defined by the leading end of the guidewire structure. However, if the guidewire structure is pulled back, it also has the consequence that the catheter must be pulled back with it.

If it is desired to enable the leading end of the catheter to protrude beyond the end of the guide wire it is traveling over, or to keep the catheter in place after the guide wire has been pulled back, this can be achieved by providing the catheter with a cutting device. realized at the front end. The use of such a catheter is illustrated in Figures 6a and 6b. 6a and 6b show guidewires 61 , 62 connected by a joint 63 and extending in an outer catheter 65 . A cutting catheter 64 surrounds one of the guide wires, in this case guide wire 61 . Catheter 64 has a cutting tip (not visible in FIG. 6 a ) which cuts joint 63 when catheter 64 is advanced over guidewire 61 . Figure 6b shows the cutting operation being partially completed.

The cutting catheter comprises a cylindrical cutting member 66 with a circular cutting portion 67 formed at its front end (visible in FIG. 6b but not in FIG. 6a ). When not in use, the cutting portion is protected by a generally cylindrical sheath 68 which is biased to a forward protected position by a compression spring 69 located at the rear end of the sheath 68 and a stopper 70 secured to the end of the conduit. When the cutting catheter is pushed forward against the force of the spring 69 , as shown in FIG. 6 b , the cutting portion 67 emerges from the sheath 68 and severes the joint 63 . Once the severing is complete, the spring automatically causes the sheath 68 to move forward, covering the cutting portion 67 and preventing it from injuring the patient.

Once, for example, a sufficiently large loop of guide wire is formed in the intestine, it becomes possible to draw the intestine back to some extent by means of friction between the loop and the intestinal wall. To do this, both guidewires are pulled back synchronously. This provides a means of straightening the bowel, which in turn makes advancing the guidewire structure further, or indeed other structures such as an endoscope, easier and less painful for the procedure, The pain is primarily caused by pulling on nerve endings in the mesentery.

The above concept of using a guide wire loop to straighten a passage such as the intestine can utilize two guide wire structures operating in parallel. An example of such an embodiment is shown in FIG. 7 . This example comprises two parallel conduits 72a, 72b, preferably connected side by side in such a way as to allow each to move longitudinally relative to each other. In the embodiment shown, the connection is provided by a T-shaped key 73 formed in conduit 72a, which is slidable in a correspondingly shaped channel 74 formed in conduit 72b. and extending longitudinally along the conduit. There may be a single keyblock, or multiple keyblocks spaced along the length of conduit 72a, or there may be a continuous keyblock extending all or part of the length of conduit 72a. Catheter 72a receives a first guidewire structure 75a comprising a pair of guidewires _w1 and _w2 connected at joint 76a. Catheter 72b receives a guidewire structure 75b comprising a pair of guidewires _w3 and _w4 connected at joint 76b.

The embodiment shown in Figure 7 can be used in a process employing the following steps:

1. Push the combination of catheters 72a and 72b into an appropriate opening (such as the anus in the case of the colon) as far as they will go.

2. Advance the guidewire _w3 as long as the loop it forms can be advanced (this is basically the configuration shown in Figure 7).

3. Pull both catheters back so that the loops in the wire structure 75b straighten the bowel.

4. Advance wire structure 75a in its unlooped form (ie wires _w1 and _w2 ) through catheter 72a to where it will go (it should pass the loop in wire structure 75b).

5. Advance catheter 72a over _w1 and _w2 so that catheter 72a leads catheter 72b while catheter 72b and the loop extending from it hold the bowel in place.

6. Advance guide wire w ₁ or guide wire w ₂ forming a loop in guide wire structure 75a and advancing it in the intestinal tract.

7. Retract the farther advanced of the two guidewires _w3 and _w4 in order to eliminate the loop in the guidewire structure 75b.

8. Advance catheter 72b so that it catches up with catheter 72a.

The cycle described above is then repeated until the desired degree of advancement has been achieved.

A similar cycle of steps can be achieved by a modification of the embodiment shown in Figure 7 in which one or each of the two conduits 72a, 72b is replaced by a suction conduit. A suction catheter may be used to achieve the bowel straightening described above by pulling the bowel back while applying suction. Said suction is only performed during the straightening step. Yet another modification replaces one of the wire structures with a soft balloon that can be inflated to engage the bowel wall and then pulled back to straighten the bowel.

Many different devices can be passed through the wire structure, some examples are given below.

(a) A small imager (such as a CCD or CMOS chip) located on the catheter can be delivered to the tip along one or more guide wires. This can optionally be advanced along the guidewire by a water jet or some other tip advancement means, thereby reducing the force that must be applied externally to the patient. It is also possible to introduce white light or colored light sources by the same means. The light source may take the form of a light emitting diode or fiber optics may be used. One of the guidewires may optionally be formed from a fiber optic bundle. It allows for easier acquisition of optical signals through lightweight insulated wires that can be incorporated into the guide wire or incorporated into the catheter with a separate wire. The imager can then convert the optical information into radio waves or microwaves, which transmit the information to an antenna attached to or near the outside of the patient.

(b) A separate soft catheter can be run over the guide wire to the tip and this can be used to introduce air from a controlled pump to inflate the viscera. Water for flushing purposes can be passed through this conduit from the water pump or through other conduits.

(c) A catheter can be passed over one of the guide wires, which catheter can provide a channel through which a biopsy can be performed. This is preferably performed after the imager mentioned in (a) has been placed in place so that the biopsy process can be observed with said imager. The catheter may have a tip angle feature.

(d) A dual lumen catheter may be passed over the dual guide wire which may allow the introduction of another guide wire which is stiffer or another guide wire with a crimped end to allow the device to be oriented in the desired direction sports.

Once the guide wire and the imager mentioned above in (a) have reached the desired location, an overtube can be delivered eg to the cecum. The guidewire and imager can then be pulled back and a conventional endoscope can be passed through the overtube to perform treatment, such as removal of polyps or malignancies.

Can be introduced into the body cavity by passing a conventional endoscope over a guide wire structure. However, conventional endoscopes may be too rigid for this to be possible, but the guide wire structure effectively offers the possibility of placing the endoscope inside the patient. To achieve this, a plurality of catheters, each providing one or more useful settings commonly used in conventional endoscopes, are passed successively through one or more of the guide wires, resulting in these The different elements are assembled inside the patient. A particular advantage of such a procedure is that the force required to advance each individual catheter is substantially less than the force required to advance an entire conventional endoscope (e.g., a colonoscope or enteroscope), which is stiffer and has Greater mass. Therefore, it is easier for the doctor, more comfortable for the patient and less likely to cause harm to the patient. Also, since the endoscope is then assembled element by element, the endoscope can have those devices that are needed by a particular patient. Or just those devices that are needed so that the endoscope is customized to the requirements of the medical procedure being performed. It will be appreciated that in order to allow "in situ" assembly of the catheter, the guidewire structure should preferably comprise more than two guidewires, such as three or four guidewires.

While a structure with more than two guidewires is particularly useful for the purposes of assembling an endoscope in situ discussed above, it can also be of value for procedures used to introduce guidewire structures into lumens. This is because the structure of the two guidewires shown in Figures 1a-1c only allows bending in one plane so that manipulating the structure in three dimensions requires the user to twist about its longitudinal axis, for example by using a catheter that can apply the necessary torque. the structure. However, if more than two guide wires are provided, it is possible to bend the structure in any plane; three guide wires are sufficient for this purpose.

Attention is now drawn to FIGS. 8 a - 8c , which illustrate the use of a guidewire structure 80 comprising two guidewires 81 , 82 connected by a joint portion 83 . It can be seen that the joint portion 83 is pivotable about an axis located at the proximal end of said portion 83 so that, as shown in FIG. Parts lay flat. This is advantageous because it makes it possible or easier to move the portion 83 within the conduit 84 not only in the absence of a loop (as shown in FIG. 8c ), but also in the presence of a loop. Below (shown in Figure 8a) are both. In this regard, it should be understood that the diameter of conduit 84 may actually be significantly larger than that shown in these Figures. It will also be appreciated that instead of being connected by a relatively long joint portion 83 as shown, the guidewire could alternatively be connected by a joint of substantially no length, i. A joint connection formed by a pivot point.

Figure 9 shows yet another guidewire configuration in which a similar pivoting action can be achieved. The structure comprises guide wires 91 , 92 having respective soft end portions 91 a , 92 a connected to each other by wires or highly flexible wires 93 . The thread or wire may be inserted into portions 91a and 92a or attached to their surfaces.

Figures 10 to 13 show guidewire structures according to the present invention. The guidewire structure includes a continuous one-piece guidewire having a section (which may generally be located in the middle portion of the guidewire) that has a bending moment of inertia that is less than the bending moment of inertia of an adjacent guidewire section. For example, the guidewire may change cross-sectional shape or size at non-terminal locations so as to form a bending hinge.

The bending moment of inertia of a circular cross-section can be calculated as πr ⁴ /4, where r is the radius of the cross-section. The bending moment of inertia of a rectangular cross-section can be calculated as bh ³ /12, where b is the length of the base of the rectangle and h is the height. "Mechanics of Materials" (ACUgural, McGraw Hill Press, 1991) is hereby incorporated by reference for its disclosure relating to bending of cross-sections.

Figure 10 illustrates one embodiment of a guidewire structure according to the present invention comprising a continuous unitary guidewire 100 having a varying cross-sectional area along a portion of its length. In this embodiment, the guidewire 100 can have a first segment 121 having a generally circular cross-section with a nominal diameter D 101 and a length L 101 , a second segment 122 and a third segment 123. The second section 122 has a generally circular cross-section with a nominal diameter D102 and a length L102, and the third section 133 has a generally circular cross-section with a nominal diameter D103 and a length L103. Guidewire 100 may include a tapered transition section 110 having a conical shape and a length L104 extending between sections 121 and 123, and a tapered transition section 112 having a length L105. Extends between segment 123 and segment 122 .

The reduced diameter D103 of the third segment 123 relative to the diameters D101 and D102 provides the third segment 123 with a bending moment of inertia that is less than the bending moments of inertia of the segments 121 and 122 . Accordingly, guidewire 100 is capable of bending at third segment 123 to form a hinge, which may include a portion or all of length L103 of third segment 123 and lengths L104 and L105 of segments 110 and 112 . In one embodiment, the hinge so formed is an elastic hinge.

Guidewire 100 with an associated hinge is used in the embodiments described below and in the methods disclosed with reference to FIGS. 1-9 without the need to secure or otherwise connect the two guidewires or use different materials.

In one embodiment, diameters D101 and D102 may be between about 0.010 inches and about 0.035 inches, more particularly between about 0.016 inches and about 0.020 inches. Third segment 123 can have a diameter D103 of between 0.005 inches and about 0.010 inches, and in one embodiment, D103 can be about 0.007 inches.

Each of L101 and L102 is at least about 3 feet, and may be between about 6 feet and about 12 feet. The combined lengths L101, L102, L103, L014, and L105 may be between about 7 feet and about 25 feet. In one embodiment, lengths L101 and L102 can be approximately equal, and their combined length can be at least about 20 feet. The length L103 of the third segment may be between about 0.100 inches and about 0.500 inches, and in one embodiment may be about 0.300 inches. Length L104 and length L105 may be approximately equal, and each may be approximately 2 inches. Modification of the cross-section of the guidewire 100 at a location intermediate the ends may be accomplished by any suitable process, such as by grinding, drawing or stamping the guidewire 100 .

In one embodiment, the reduced cross-section of third segment 123 may be formed by centerless grinding. The reduced cross-section can be formed using a grinder such as the TF-9CPG System 2000 Guidewire Profile Grinder available from the Glebar Company of Flanklin Lakes, NY.

Guidewire 100 is encapsulated in one or more low friction and/or lubricated sheaths. In FIG. 11 , first wire segment 121 is encapsulated in sleeve 155 , second wire segment 122 is encapsulated in sleeve 159 , and the third segment and the transition segment are encapsulated in sleeve 157 . Sleeves 155, 157 and 159 may be formed from a low friction material such as PTFE or polyester. Indicators may be associated with the first and second wire segments 121 and 122 so that the wire segments can be distinguished when viewed through a video camera or other optical device associated with an endoscope or other medical device. For example, the indicator is visible and can use different colors. In one embodiment, sleeves 155 and 159 can be formed in different colors and/or have different marking patterns. In FIG. 13, sleeve 155 has a heavy diagonally beveled marking pattern, while sleeve 159 has a light, non-sloping marking pattern. The color of the indicia and/or the background color of the cannula can be different to distinguish cannula 155 from cannula 159 . Alternating bands of different colors may also be used to distinguish sleeve 155 from sleeve 159 , and thus segments 121 and 121 , when viewed through visual means. Sleeve 157 may have another color or pattern of colors to provide a visual indication as to the location of third section 123 .

Figure 11 shows guidewire 100 bent at third section 123 to form a narrow guidewire loop for guidance into a body lumen. In FIG. 11 , the guide wire 100 is shown having a generally U-shaped bend 150 with a radius R110 so that the guide wire does not kink when placed through the working channel of the colonoscope and does not form a kinked joint when placed in the body cavity. Sharp points that damage tissue, preferably substantially without plastic deformation. In one embodiment, radius R110 may be about 0.75 mm to about 1.5 mm, especially about 1 mm.

Suitable biocompatible materials of construction for such a guidewire include those mentioned above from which the guidewire of FIGS. 1-9 can be formed, including but not limited to superelastic materials such as Nitinol. Other materials such as steel and alloys may also be used. One suitable material from which guidewire 100 can be formed is Nitinol NDCSE508 available from Nitinol Devices and Components, a Johnson & Johnson Company of Frement, California.

Figure 12 shows an alternative embodiment in which the cross-section with shortened length 103 is not round. Different cross-sectional shapes can be formed, for example, the circular guide wire can be changed into a flat rectangular cross-section in FIG. 12a, an elliptical cross-section in FIG. 12b, or a square cross-section in FIG. 12c. Other cross-sectional shapes may also be used, such as triangular, hexagonal or other polygonal shapes. A preferred curved plane with a specific cross-sectional shape can be used to guide the U-shaped loop of the guidewire. For example, rectangular, elliptical or triangular cross-sections can be used to guide bending about a particular axis.

The guidewire configuration with guidewire 100 of the present invention can be used in place of the guidewire configurations shown in FIGS. , that application is included here by reference. FIG. 13 is a schematic illustration of a guidewire configuration with guidewire 100 for use with medical device 300 . In general, the medical device 300 may be a flexible endoscope, such as a flexible colonoscope, or a device as shown in the patent application cited above.

The medical device 300 can include a handle 310 external to the patient, an elongated flexible body portion 330, and a distal end 320 that can be placed inside the patient (e.g., within the patient's GI tract), the distal end 320 being sized and shaped Be set up to be able to progress within the GI tract. The medical device may also include a working channel 350 extending through body portion 330 and opening at distal end 320 of device 300, camera 360, light source 370, camera lens cleaning nozzle/rinse nozzle 380, light source 392, and light source 394. Suction may be provided through working channel 350 if desired.

The guidewire structure of the present invention with guidewire 100 can be positioned in working channel 350 such that the U-shaped bend in third section 123 is positioned within the patient and the end of the guidewire extends through handle 310 import and export. In FIG. 13 , the ends of the guide wire are indicated by reference numeral 221 (associated with first segment 121 ) and reference numeral 222 (associated with second segment 122 ).

A guidewire configuration with guidewire 100 as shown in FIGS. 3A-3C may generally be used to advance a device into a body lumen, such as the gastrointestinal tract. In FIG. 13 , after the U-shaped bend within third section 123 has advanced through working channel 350, first section 121 is advanced through the working channel relative to second section 122 such that first section 121 assumes a radius of curvature greater than the radius of curvature of R110, as shown in Figure 13. To advance distal end 320 further into the patient, the operator may pull end 220 proximally to move third section 123 rearwardly into working channel 350, thereby leaving the first section 121 within the body lumen. A loop having a relatively large radius of curvature extends from the distal end of the device 300. End 222 may then be held fixed and end 221 may be advanced distally toward handle 310 so that the remaining length of first section 121 is advanced distally out of working channel 350, thereby allowing a relatively greater curvature The loop of radius is advanced distally into the gastrointestinal tract. Then, while keeping end 222 fixed relative to handle 310, end 221 can be tensioned (proximally) and simultaneously push the elongated body portion distally along guidewire segments 121 and 122 within working channel 350 330, thereby bringing the distal end 350 forward (distal) into the gastrointestinal tract. Thus, guidewire segments 121 and 122 may serve as a kind of track along which distal end 350 of device 300 may be advanced.

While the present invention has been described by the description of several embodiments, it is not the applicant's intention that the spirit and scope of the invention appended hereto be constrained or limited to such specific scope. Various modifications, changes and substitutions may be made by those skilled in the art without departing from the scope of the present invention. Also, the structure of each element associated with the present invention can alternatively be described as a means for providing the function performed by the element. It is to be understood that the foregoing description is given by way of example, and that other modifications may be made by one of ordinary skill in the art without departing from the spirit and scope of the appended claims.

Claims (23)

1. A guide wire structure for introducing a catheter or other instrument into an interior space defined by walls, the guide wire structure comprising a continuous integral guide wire having a first segment, a second segment and A third section disposed between the first section and the second section, wherein the bending moment of inertia of the third section is smaller than the bending moment of inertia of the first section and smaller than the bending moment of inertia of the second section, the guide wire is suitable for Three sections are bent to form a guide wire loop for guiding into the inner space. 2. The guide wire structure according to claim 1, wherein the cross-sectional area of the third segment is smaller than the cross-sectional areas of the first segment and the second segment. 3. The guidewire structure of claim 1, wherein at least one of the first, second, and third segments has a circular cross-section. 4. The guidewire structure of claim 1, wherein at least one of the first, second, and third segments has a non-circular cross-section. 5. The guidewire structure of claim 1, wherein the guidewire is formed of Nitinol. 6. The guidewire structure of claim 1, further comprising an indicator associated with at least one segment for distinguishing the segments. 7. The guidewire structure of claim 6, wherein the indicator comprises a visual indicator. 8. The guidewire structure of claim 7, wherein the indicator comprises a marker associated with at least one segment. 9. The guidewire structure of claim 1, comprising a sleeve surrounding at least one of the first and second segments. 10. The guidewire structure of claim 1 including a sleeve surrounding each of the first and second segments. 11. The guidewire structure of claim 1, comprising a sleeve surrounding the first segment and a sleeve surrounding the second segment, wherein the first and second sleeves are visually distinguishable. 12. The guidewire structure of claim 1, wherein the combined length of the first, second, and third segments is at least 7 feet. 13. The guidewire structure of claim 1, wherein the combined length of the first, second, and third segments is between 7 feet and 25 feet. 14. The guidewire structure of claim 1, wherein the combined length of the first, second, and third segments is at least 20 feet. 15. The guidewire structure of claim 1, wherein the first segment has a length of at least 6 feet and a substantially circular cross-section with a diameter between 0.011 inches and 0.035 inches. 16. The guidewire structure of claim 15, wherein the diameter of the third section is between 0.005 inches and 0.010 inches. 17. The guidewire structure of claim 1 , wherein the length of the first section is at least 6 feet, the first section has a maximum cross-sectional dimension of no greater than 0.035 inches, and the third section has a length of no greater than 0.035 inches. 0.010 inch maximum cross-sectional dimension. 18. The guidewire structure of claim 1, wherein the third section is curved. 19. The guidewire structure of claim 1, wherein the third section provides a resilient hinge. 20. A guidewire structure for introducing a catheter or other instrument into an interior space defined by a wall, comprising: a first section having a substantially constant diameter; a second section having a substantially constant diameter; a third section having a substantially constant diameter that is less than the diameters of the first and second sections; a tapered section having a gradually decreasing diameter extending from the first section to the third section; and a tapered section having a gradually decreasing diameter extending from the second section to a third section, wherein the guidewire structure is adapted to bend at the third section to form a guidewire for guiding into the interior space ring. 21. A method of using a guide wire comprising the steps of: A guide wire is provided, the guide wire includes a continuous integral guide wire, the guide wire has a first segment, a second segment and a third segment disposed between the first segment and the second segment, wherein the third segment The bending moment of inertia is less than the bending moment of inertia of the first section and less than the bending moment of inertia of the second section, the guidewire is adapted to bend at the third section to form a guidewire loop for guiding into the inner space ; providing a medical device with access; bending the guidewire at a location with a reduced bending moment of inertia; and The curved portion of the guidewire is inserted into the channel of the medical device. 22. The method of claim 21, further comprising the step of passing the bend in the guidewire through the distal end of the medical device. 23. The method of claim 21, further comprising the step of advancing the medical device over a guide wire.

Images