U.S. patent application number 10/729754 was filed with the patent office on 2004-10-07 for guide wire having bending segment.
Invention is credited to Bakos, Gregory J., Gee, Kevin K., Long, Gary L., Swain, Christopher Paul, Tierney, Scott J..
Application Number | 20040199088 10/729754 |
Document ID | / |
Family ID | 9956120 |
Filed Date | 2004-10-07 |
United States Patent
Application |
20040199088 |
Kind Code |
A1 |
Bakos, Gregory J. ; et
al. |
October 7, 2004 |
Guide wire having bending segment
Abstract
A guide wire including a continuous, unitary wire having a first
segment, a second segment, and a third segment is shown and
described. The third segment has a bending moment of inertia less
than the bending moment of inertia of the first and second
segments. The guide wire can be used to advance a medical device
within a body lumen.
Inventors: |
Bakos, Gregory J.; (Mason,
OH) ; Gee, Kevin K.; (Scituate, MA) ; Tierney,
Scott J.; (Taunton, MA) ; Swain, Christopher
Paul; (London, GB) ; Long, Gary L.; (Gerrards
Cross, GB) |
Correspondence
Address: |
PHILIP S. JOHNSON
JOHNSON & JOHNSON
ONE JOHNSON & JOHNSON PLAZA
NEW BRUNSWICK
NJ
08933-7003
US
|
Family ID: |
9956120 |
Appl. No.: |
10/729754 |
Filed: |
December 5, 2003 |
Current U.S.
Class: |
600/585 |
Current CPC
Class: |
A61B 1/31 20130101; A61B
2017/003 20130101; A61M 25/09 20130101; A61M 25/09025 20130101;
A61M 2025/09133 20130101; A61M 2025/09175 20130101 |
Class at
Publication: |
600/585 |
International
Class: |
A61B 005/00 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 3, 2003 |
GB |
0307715.3 |
Claims
What is claimed:
1. A guide wire structure for insertion into an interior space
defined by a wall, the guide wire comprising a continuous, unitary
wire comprising a first segment, a second segment, and a third
segment disposed intermediate the first and second segments,
wherein the third segment has a bending moment of inertia less than
a bending moment of inertia of the first segment and less than a
bending moment of inertia of the second segment.
2. The guide wire structure of claim 1 wherein the third segment
has a cross-sectional area less than the cross sectional areas of
the first segment and the second segment.
3. The guide wire structure of claim 1 wherein at least one of the
first, second, and third segments have circular cross sections.
4. The guide wire structure of claim 1 wherein at least one of the
first, second and third segments have non-circular
cross-sections.
5. The guide wire structure of claim 1 wherein the wire is formed
of Nitinol.
6. The guide wire structure of claim 1 further comprising an
indicator associated with at least one of the segments for
differentiating the segments.
7. The guide wire structure of claim 7 wherein the indicator
comprises a visual indicator.
8. The guide wire structure of claim 7 wherein the indicator
comprises a marking associated with at least one of the
segments.
9. The guide wire structure of claim 1 comprising a sleeve
encircling at least one of the first and second segments.
10. The guide wire structure of claim 1 comprising a sleeve
encircling each of the first and second segments.
11. The guide wire structure of claim 1 comprising a sleeve
encircling the first segment and a sleeve encircling the second
segment, wherein the first and second sleeves are visually
distinguishable.
12. The guide wire structure of claim 1 wherein the combined length
of the first segment, the second segment, and the third segment is
at least about 7 feet.
13. The guide wire structure of claim 1 wherein the combined length
of the first segment, the second segment, and the third segment is
between about 7 feet and about 25 feet.
14. The guide wire structure of claim 1 wherein the combined length
of the first segment, the second segment, and the third segment is
at least about 20 feet.
15. The guide wire structure of claim 1 wherein the first segment
has a length of at least about 6 feet, and a generally circular
cross-section having a diameter of between about 0.011 inch to
about 0.035 inch.
16. The guide wire structure of claim 15 wherein the third segment
has a diameter of between about 0.005 inch and about 0.010
inch.
17. The guide wire structure of claim 1 wherein the first segment
has a length of at least about 6 feet, wherein the first segment
has maximum cross-sectional dimension of no more than about 0.035
inch, and wherein the third segment has a maximum cross-sectional
dimension of no more than about 0.010 inch.
18. The guide wire structure of claim 1 wherein the third segment
is bent.
19. The guide wire structure of claim 1 wherein the third segment
provides an elastic hinge.
20. A guide wire structure comprising: a first segment of a
generally constant diameter; a second segment of generally constant
diameter; a third segment having a generally constant diameter less
than that of the first and second segment diameters; a tapered
segment of decreasing diameter extending from the first segment to
the third segment; and a tapered segment of decreasing diameter
extending from the second segment to the third segment.
21. A method of using a guide wire comprising the steps of:
providing a guide wire comprising a unitary wire having reduced
bending moment of inertia at a position spaced from the ends of the
guide wire; providing a medical device having a channel; bending
the wire at the position of the reduced bending moment of inertia;
and inserting the bend in the wire into the channel of the medical
device.
22. The method of claim 21 further comprising the step of passing
the bend in the wire through a distal end of the medical
device.
23. The method of claim 21 further comprising the step of advancing
the medical device along the wire.
Description
[0001] This patent application incorporates by reference U.S.
patent application Ser. No. 10/409,270 "Guide Wire Structure for
Insertion into an Internal Space" filed Apr. 8, 2003, and U.S.
patent application Ser. No. 10/406,020 "Medical Device with Track
and Method for Use" filed Apr. 3, 2003
FIELD OF THE INVENTION
[0002] The present invention is related generally to a guide wire
structure. In one embodiment, the invention is directed to a guide
wire structure which can be inserted into an interior space within
a human or animal body, such as the gastrointestinal (GI) tract of
a human patient.
BACKGROUND OF THE INVENTION
[0003] A physician typically accesses and visualizes tissue within
a patient's gastrointestinal (GI) tract with a long, flexible
endoscope. For the upper GI, a physician may insert a gastroscope
into the sedated patient's mouth to examine and treat tissue in the
esophagus, stomach, and proximal duodenum. For the lower GI, a
physician may insert a colonoscope through the sedated patient's
anus to examine the rectum and colon. Some endoscopes have a
working channel, typically about 2.5-3.5 mm in diameter, extending
from a port in the handpiece to the distal top of the flexible
shaft. A physician may insert medical instruments into the working
channel to help diagnose or treat tissues within the patient.
Physicians commonly take tissue biopsies from the mucosal lining of
the GI tract using a flexible, biopsy forceps through the working
channel of the endoscope.
[0004] Insertion of a flexible endoscope, especially into the
colon, can be very time-consuming and uncomfortable procedure for
the patient, even when sedated with drugs. A physician often needs
several minutes to push a flexible endoscope through the convoluted
sigmoid, descending, transverse, and ascending portions of the
colon. The physician may diagnose and/or treat tissues within the
colon either during insertion or removal of the endoscope. The
flexible endoscope may "loop" within the colon, such as at the
sigmoid colon or at the splenic flexure of the colon, so that it
becomes difficult to further advance the endoscope along the colon.
When a loop is formed, the force exerted to push the scope
stretches the mesentery and causes pain for the patient. Depending
on the anatomy of the patient and the skill of the physician in
manipulating the flexible endoscope, some portions of the colon may
be unexamined, thus increasing the risk of undiagnosed disease.
[0005] Guide wires have been used to aid the introduction of
catheters and other instruments into many sites in the human body.
Many medical applications and specific designs of guide wires have
been for cardiovascular use. There are, however, specific
challenges relates to the use of guide wires in the GI tract, as
opposed to the vascular system. Thus, the bowel is more tortuous,
softer and generally of larger diameter. Furthermore, in the case
of the small intestine and the colon, these are longer than most
arteries or veins.
SUMMARY OF THE INVENTION
[0006] In one embodiment, the present invention provides a guide
wire structure for use with a medical device for insertion into a
body lumen, such as the GI tract. The guide wire structure
comprises a continuous, unitary wire comprising at least a first
segment, a second segment, and a third segment disposed
intermediate the first and second segments. The third segment has a
bending moment of inertia less than a bending moment of inertia of
the first segment and less than a bending moment of inertia of the
second segment. The third segment can provide a flexible hinge for
bending of the unitary wire. By the phrase "continuous, unitary
wire" it is meant the portion of the wire associated with the third
segment and adjacent portions of the first and second segments do
not include any joints, junctures, or other connections (such as
for instance welds, braze joints, or solder joints), although the
ends of the wire may include a joint or connection for connecting
the wire to a handle or for other purposes. In one embodiment the
wire is formed of a single material, such as a superelastic
material. One suitable material from which the wire may be formed
is Nitinol.
[0007] In one embodiment, the third segment has a cross-sectional
area less than the cross sectional areas of the first segment and
the second segment. The reduced cross-sectonal area of the third
segment can be formed by grinding the outer diameter of the wire to
form a reduced cross-sectional area third segment between first and
second segments having a generally constant cross sectional area.
The wire can have a circular cross-section, or alternatively,
non-circular cross-sections. A generally conical transistion
segment can extend from each end of the third segment to connect
the third segment to the first and second segments.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] The invention is described further below with reference to
the accompanying drawings, in which:
[0009] FIG. 1a shows an embodiment of guide wire structure as
disclosed in U.S. patent application Ser. No. 10/409,270;
[0010] FIG. 1b shows the structure of FIG. 1a when one of its guide
wires is advanced rightwardly and the other is held steady;
[0011] FIG. 1c shows the structure of FIG. 1a after further
righthand advance of one of the guide wires;
[0012] FIG. 2 shows an example of a pattern of markings which may
be provided on the guide wires to indicate their relative position
to a physician;
[0013] FIG. 3a to 3c show a guide wire structure advancing into the
colon;
[0014] FIG. 4 shows diagrammatically a handle for use in
controlling movement of guide wires;
[0015] FIGS. 5a and 5b show successive stages in the use of a guide
wire structure in conjunction with a bias tube;
[0016] FIGS. 6a and 6b show successive stages in the use of a
cutting catheter to sever the junction between two guide wires;
[0017] FIG. 7 shows two guide wire structures arranged in
parallel;
[0018] FIGS. 8a to 8c illustrate diagrammatically the use of a
guide wire structure which has a pivotal junction portion;
[0019] FIG. 9 shows another guide wire structure described in U.S.
application Ser. No. 10/409,270.
[0020] FIG. 10 illustrates an embodiment of the present invention
in which a guidewire cross section is varied along its length to
have a reduced cross section at a location spaced from the ends of
the wire, such as at or close to the midpoint of length of the
guide wire.
[0021] FIG. 11 shows the guide wire of FIG. 10 bent into a
generally U-shaped configuration for passage into a lumen such as
the GI tract.
[0022] FIGS. 12a, b, and c show alternative embodiments in which
different cross-sections are employed.
[0023] FIG. 13 illustrates an embodiment of the guide wire of the
present invention being advanced from the distal end of a medical
device to form a loop forward of the distal end of the medical
device.
DETAILED DESCRIPTION
[0024] FIGS. 1-9 illustrate guide wire structures disclosed in U.S.
patent application Ser. No. 10/409,270, incorporated herein by
reference. FIGS. 10-13 illustrate a guide wire structure according
to the present invention.
[0025] The structure of FIG. 1a comprises a first guide wire 1 and
a second guide wire 2, the wires 1 and 2 being connected to one
another by a junction 3 formed at the leading ends of the wires 1
and 2. Although the junction 3 is shown as being at the leading
ends, it could alternatively be adjacent the leading ends. The
length of the junction need be no more than is necessary to hold
the leading ends securely together side by side. Depending on the
nature of the junction, a length of as little as 5-10 mm may be
sufficient, though a greater length may sometimes be
preferable.
[0026] The guide wires 2 and 3 can be made of the materials
conventionally used for guide wires, for example straight stainless
steel wire, coiled stainless steel wire, glass fiber, a plastics
material, or nitinol. Conveniently, a guide wire has a floppy tip,
i.e. a leading end portion, typically 4-5 cm in length, of greater
flexibility than the remainder of the guide wire, in order to
reduce the risk of the leading end of the guide wire causing damage
to the wall of the lumen through which it is passing. Where two
such conventional guide wires are joined together to produce the
guide wire structure of FIG. 1, it can be these floppy tips, or
parts thereof, which are joined together. The length of the
junction can be less than the length of the floppy tips, so that
some length of floppy material remains which is unaffected by the
junction.
[0027] The whole or part of each of the guide wires may be coated
to reduce its coefficient of friction, as is done with conventional
guide wires. For example, guide wires can be coated with a low
friction material such as silicone, or with a hydrophilic material
which becomes slippery in use in a patient, or with both a low
friction material such as silicone and hydrophilic material applied
over the low friction material.
[0028] The junction 3 can be formed in any desired manner, provided
the resulting leading end of the guide wire structure is not such
as to damage the wall of the GI tract or other body lumen, nor
cause undue pain when in contact therewith. For example, the
junction can be made by gluing or welding the leading end portions
together and then covering those portions with heat shrink tubing.
Alternatively, the end portions could be held together by having a
metal band crimped on to them, optionally enclosed by a cover made
of a softer material.
[0029] It is not essential for all the guide wires, or both the
guide wires, as the case may be, to be of material which would
normally be regarded as guide wire material. For example, in the
case of a guide wire structure consisting of just two guide wires,
one of the guide wires may be made of a thread, which is joined to
the other guide wire by being tied to it.
[0030] Another possibility would be to start with a single guide
wire of twice the required length and fold it sharply back on
itself, for example by crimping the folded wire adjacent the fold,
so that it became, in effect, a pair of guide wires joined at the
fold. A guide wire structure having an even number n of guide wires
greater than two could be formed by folding half that number of
guide wires.
[0031] The principle of operation of the guide wire structure can
be seen by comparing FIGS. 1b and 1c with FIG. 1a. FIG. 1b shows
the result of advancing the guide wire 1 rightwardly, as indicated
by the arrow, whilst holding the guide wire 2 still. As indicated
in FIG. 1b, this causes the distal region of the guide wire
structure to curve in a direction so that the advanced guide wire 1
is on the outside of the curve and the still guide wire 2 is on the
inside of the curve. Continued advancement of guide wire 1 beyond
the position illustrated in FIG. 1b, whilst continuing to hold
guide wire 2 steady, results in the formation of a loop in an end
region of guide wire 1. This is illustrated in FIG. 1c, where the
loop is denoted by reference numeral 4.
[0032] To enable the physician to easily advance one of the guide
wires while keeping the other still, the guide wires can be
received, at their ends remote from the junction 3, in a handle
which can be moved up and down the guide wires as they are advanced
and retracted. The handle should allow precise regulation of the
relative lengths of the two guide wires. It should also allow the
introduction of the various catheters, imagers and other
accessories, discussed in more detail below, giving accurate
information on their relationship to the junction 3. The handle may
be provided with a reversible motor drive which enables both guide
wires to be driven. The motor drive itself may provide data to
enable the user to monitor the lengths of the guide wires which
have been fed forward.
[0033] An example of a handle is illustrated in FIG. 4. The
illustrated handle 40 comprises a pistol grip 41 within which is
mounted a pair of electric motors 42 (of which one is shown)
powered either by a battery 43 or a mains supply 44. The motors are
controlled by respective finger controls 45, one for each motor,
each control having forward, reverse and stop positions. Each motor
provides drive, via a respective gear, shown diagrammatically at
46, to a respective belt or chain drive 47, each of which propels a
respective guide wire 48 forwardly (or backwardly). A switch 47a is
provided to cause the driving belts or chains to move away from the
wires, to allow the wires to be released, for example at the
conclusion of a procedure. A lock mechanism 49 is provided to
attach the handle 40 to a catheter or to an accepting channel of an
endoscope, through which the guide wire is to be driven. The guide
wires are stored in a coiled plastics tube 50, either with both
wires side by side in a single tube or each in its own tube. This
has the benefit of keeping the guide wires clean, and avoiding the
risk of their trailing on to the floor. Under some conditions this
storage facility may be omitted.
[0034] The combined effect of the forms of behaviour illustrated in
FIGS. 1b and 1c enables the guide wire structure to perform in a
highly advantageous manner. Thus, causing the structure to become
curved, as shown in FIG. 1b, enables the physician to steer the
leading end of the structure round bends in the lumen through which
the structure is being advanced. The ability to form a loop, as
illustrated in FIG. 1c, enables the guide wire structure to adopt
as configuration in which it can be safely advanced along the
lumen, without undue discomfort for the patient.
[0035] Furthermore, the presence of a loop at the leading end of
the structure rather than the tip of a single wire, makes the
structure more likely to follow the main course of the lumen, and
less likely to inadvertently enter branches off it. Thus, in the
case of the gut, there will be a much reduced tendency to enter,
for example, diverticulae or the orifice of the appendix. However,
the fact that the loop is not permanently present, and can be
eliminated by putting the structure into the configuration shown in
FIG. 1a, means that the structure can easily, and without damage to
itself, be passed along a very narrow passageway. It can therefore
be passed, for example, along a channel of an endoscope or down a
catheter, as is described further below. Also, when the guide wire
structure is not in an endoscope or catheter, but is advancing
directly along a patient lumen, it is not always desirable to do so
with a loop at the front (for example if it has to pass through a
small opening). Under such circumstances the guide wire structure
is allowed to revert to the straight form shown in FIG. 1a with
both guidewires being advanced aligned and in unison.
[0036] FIGS. 3a to 3c show diagrammatically, and by way of example,
successive stages in advancing the guide wire structure along a
colon 30. It is shown being introduced in conjunction with a
catheter 31 within which the whole guide wire structure is slidably
received. The individual guide wires are denoted as w.sub.1 and
w.sub.2. Advancement takes place by alternately:
[0037] (a) pushing one wire forward while holding the other still;
and
[0038] (b) pushing the catheter forwards as far as the position
shows in FIG. 3c, or even somewhat further.
[0039] It is desirable in endoscopic procedures to avoid, or at
least reduce, the use of X-ray imaging to monitor what is taking
place. With this in mind, the guide wires are preferably each
provided with a pattern of markings, distributed along their
length, to indicate how far each individual guide wire has been
inserted. One such pattern in shown in FIG. 2. As shown there, a
pattern of markings in a given colour, and similar in nature to a
bar code, is spaced along a first length (L.sub.1), and then
repeated along successive lengths (of which only L.sub.2 is shown)
each time in a different colour. Each of the lengths could
conveniently be of the order of 10 cm. This provides a method by
which the physician can easily see which of the guide wires is the
further advanced, and by how much, and enable him, for example, to
make the inserted lengths equal and thus eliminate any curve (FIG.
1b) or loop (FIG. 1c). Of course, many other patterns of marking,
for example numerals or letters, could be used instead of that
illustrated, which is given only as an example.
[0040] Additionally, or instead, the guide wire structure can be
provided with other forms of position indication. It is known to
provide a conventional guide wire with a series of miniature
electrically conductive coils which surrounded the guide wire and
are spaced along its length, the coils being connected to a source
of electrical current, whereby each coil becomes a miniature
electromagnet. Such coils can be provided on the guide wires used
to form the guide wire structure shown. A sensing device outside
the patient is used to detect the position of the coils within the
patient, and thereby determine the location of the guide wires.
[0041] The path of the guide wire structure can be influenced by
the use of a catheter, which can be passed over one or both of the
two guide wires, when there are precisely two, or over one, some,
or all of the guide wires, when there are more than two. In one
embodiment the catheter has a curved tip, which allows the
application of torque to bias the forward motion of the guide wire
(or wires) over which it passes in any given direction. The use of
a catheter in this way is illustrated in FIGS. 5a and 5b. FIGS. 5a
and 5b show a pair of guide wires 51 and 52 joined at a junction
53. Guide wire 51 is received within a catheter 54, referred to
herein as a bias tube, the leading end portion of which is so
formed as to have a curvature in it. The guide wire 51 with the
bias tube, and the guide wire 52, are both received within an outer
catheter 55. The ends of the catheters 51 and 52 remote from their
tips emerge from the catheter 55 to allow them to selectively
advance and retract. The end of the bias tube 54 remote from the
curved end thereof emerges from the outer catheter 55 at the user's
end. As can be seen by comparing the state shown in FIG. 5a with
the subsequent state shown in FIG. 5b, in advancing both the guide
wires, but advancing guide wire 51 more than guide wire 52, the
bias tube helps to ensure that the combined guide wire structure
curves in the desired direction. If it were desired to cause the
structure to advance in some other direction, this could be
achieved by twisting the catheter 55 about its longitudinal axis,
thus altering the positions of the guide wires relative to the
lumen in which they are being advanced.
[0042] The purpose of the guide wire is, as its name indicates, to
act as a guide for some other element. Accordingly, when the guide
wire structure is in place some other element is then passed over
it, or otherwise pushed or advanced along the guide wire.
[0043] As in the case of a catheter used to influence the path of a
guide wire structure during passage of the guide wire structure
along a lumen, a catheter introduced subsequently can pass over one
or both of the guide wires, when there are precisely two, or over
one, some, or all of the guide wires, when there are more than two.
When the catheter is passed over both, or all, the guide wires, as
the case may be, the leading end of the catheter will be free to
pass beyond the leading end of the guide wire structure once it
reaches that point. If the catheter is not passed over both, or
all, the guide wires, for example if it is passed over only one of
two interconnected guide wires, the leading end of the catheter
will normally be unable to pass beyond the connection between the
guide wires. That may be desirable, for the purpose of ensuring
that the leading end of the catheter can be brought to a position
previously defined by the leading end of the guide wire structure.
It also has the result, however, that if the guide wire structure
is withdrawn, the catheter must be withdrawn with it.
[0044] If it is desired to enable the leading end of the catheter
to pass beyond the end of the guide wire over which it is
traveling, or to enable the catheter to remain in position after
the guide wire has been withdrawn, this can be achieved by
providing the leading end of the catheter with a cutting device.
The use of such a catheter is illustrated in FIGS. 6a and 6b. FIGS.
6a and 6b show guide wires 61 and 62 connected by a junction 63 and
extending within an outer catheter 65. A cutting catheter 64
surrounds one of the guide wires, in this case the guide wire 61.
The catheter 64 has a cutting tip (not visible in FIG. 6a) which,
when the catheter 64 is advanced over the guide wire 61, severs the
junction 63. FIG. 6b shows the severing operation partly
completed.
[0045] The cutting catheter comprises a cylindrical cutting member
66 with a circular cutting edge 67 (visible in FIG. 6b but not in
FIG. 6a) formed at its leading end. When not in use the cutting
edge is shielded by a generally cylindrical sheath 68 which is
biased to a forward protecting position by a compression spring 69
located between the rearward end of the sheath 68 and a stop 70
fixed to the end of the catheter. When the cutting catheter is
pushed forwards, against the force of the spring 69, as it is in
FIG. 6b, the cutting edge 67 emerges from the sheath 68 and severs
the junction 63. As soon as severing is completed the spring
automatically causes the sheath 68 to move forwards, covering the
cutting edge 67 and preventing it from harming the patient.
[0046] Once a sufficiently large guide wire loop has been formed
in, say, the gut, it becomes possible to pull the gut backwards to
some extent, using the friction between the loop and the wall of
the gut. To do this, both guide wires are pulled backwards in
synchronism. This provides a means for straightening the gut, and
this in turn makes it easier to advance the guide wire structure
further or, indeed, to advance other structures (e.g. endoscopes),
and reduces the pain of the procedure, which is mainly caused by
stretching nerve endings in the mesentery.
[0047] The above described concept of using a guide wire loop to
straighten a passageway, e.g. the gut, can employ two guide wire
structures operating in parallel. An example of such an embodiment
is shown in FIG. 7. This comprises two parallel catheters 72a and
72b, which are preferably connected together side by side in such a
way as to allow each to move longitudinally with respect to the
other. In the illustrated embodiment the connection is provided by
a T-shaped stud 73 formed on catheter 72a which is slidable in a
correspondingly shaped passageway 74 formed in catheter 72b and
running longitudinally along it. A single stud may be provided, or
a plurality of studs spaced along the length of catheter 72a, or
there may be a continuous stud running along all or part of the
length of catheter 72a. Catheter 72a receives a first guide wire
structure 75a, comprising a pair of wires w.sub.1 and w.sub.2
joined at a junction 76a. Catheter 72b receives a guide wire
structure 75b, comprising a pair of wires W.sub.3 and W.sub.4
joined at a junction 76b.
[0048] The embodiment shown in FIG. 7 can be used in a procedure
which employs the following steps:
[0049] 1. Push the combination of catheters 72a and 72b into an
appropriate orifice, e.g. the anus in the case of the colon, as far
as they will go.
[0050] 2. Advance wire W.sub.3 as far as the loop which it forms is
able to travel (this is substantially the configuration shown in
FIG. 7).
[0051] 3. Pull back on both catheters so that the loop in guide
wire structure 75b straightens the gut.
[0052] 4. Advance guide wire structure 75a in its unlooped form,
i.e. wires w.sub.1 and w.sub.2, through the catheter 72a as far as
it will go (which should be past the loop in guide wire structure
75b).
[0053] 5. Advance catheter 72a over w.sub.1 and w.sub.2 so that it
is ahead of catheter 72b, while catheter 72a, and the loop
extending from the catheter, hold the gut in position.
[0054] 6. Advance guide wire w.sub.1 or guide wire w.sub.2 so that
a loop is formed in guide wire structure 75a and advances in the
gut.
[0055] 7. Withdraw whichever of wires W.sub.3 and W.sub.4 is the
more forward of the two, so as to eliminate the loop in guide wire
structure 75b.
[0056] 8. Advance catheter 72b so that it catches up with catheter
72a.
[0057] The above cycle is then repeated until the desired degree of
advancement has been achieved.
[0058] A similar cycle of steps can be achieved by a modified form
of the embodiment of FIG. 7, in which one or each of the two
catheters 72a and 72b is replaced by a suction catheter. A suction
catheter can be used to effect the above described straightening of
the gut by pulling back on it while suction is being applied. The
suction is only applied during the straightening step. Yet another
modification is to replace one of the guide wire structures by a
soft balloon, which can be inflated to engage the gut wall, and
then pulled back to straighten the gut.
[0059] Many different devices can be passed over the guide wire
structure, and some examples will now be given.
[0060] (a) A small imager (for example a CCD or CMOS chip) on a
catheter could be passed along the guide wire or guide wires to the
tip. This could optionally be propelled along the guide wire by a
water jet or some other means of tip propulsion to reduce the force
that has to be exerted outside the patient. A source of white or
coloured light could be also introduced by the same means. This
source could be in the form of light emitting diodes or could use
fibre-optics. One of the wires could be optionally formed out of a
fiberoptic bundle. It would be easier to take the optical signal
through a light-weight insulated wire which could be incorporated
into the guide wire or via a separate wire in a catheter. The
imager could then convert the optical information to radiowaves or
microwaves, to send the information to an aerial attached to, or
adjacent to, the exterior of the patient.
[0061] (b) A separate soft catheter could be run over the guide
wire to the tip and this could be used to introduce air from a
controlled pump to inflate the viscus. Water for rinsing purposes
could be passed through this catheter or through some other from a
water pump.
[0062] (c) A catheter could be passed over one of the guide wires,
which would provide a channel through which biopsies could be
performed. This is preferably done after the imager referred to in
(a) above has been placed in position, so that the imager can be
used to view the biopsy procedure. This catheter might have tip
angulation properties.
[0063] (d) A double lumen catheter could be passed over the double
wire, which might allow the introduction of another wire of greater
stiffness or with a curled tip to allow the movement of the device
in a desired direction.
[0064] Once the guide wire, and the imager referred to in (a)
above, have reached the desired location, an overtube could be
passed, for example to the cecum. The guide wire and the imager
could then be withdrawn and a conventional endoscope could be
passed through the overtube to deliver therapy, for example
removing a polyp or cancer.
[0065] A conventional endoscope could be introduced into a body
lumen by passing it over the guide wire structure. However, a
conventional endoscope may be too stiff for this to be possible,
and the guide wire structure offers the possibility of, in effect,
constructing an endoscope within a patient. To achieve this, a
number of catheters, each providing one or more of the utilities
normally provided a conventional endoscope, are successively passed
over one or more of the guide wires, so that result is an
assemblage of these various elements within the patient. A
particular advantage of proceeding in this way is that the force
required to advance each of the individual catheters is
substantially less than that required to advance a complete
conventional endoscope (e.g. a colonoscope or an enteroscope),
since the latter is much stiffer and has much greater mass. It is
therefore easier for the physician, and less uncomfortable for the
patient, and is less likely to cause injury to the patient. Also,
since the endoscope is then assembled element by element, the
endoscope can have those facilities which are required for the
particular patient, and, only those facilities, so that the
endoscope is tailored to the requirements of the medical procedure
being carried out. It will be understood that, for the purpose of
allowing in situ assembly of a catheter, the guide wire structure
should preferably comprise more than two guide wires, for example
three or four guide wires.
[0066] Although a structure having more than two guide wires is
particularly useful for the purpose discussed above of assembling
an endoscope in situ, it may also have value in relation to the
procedure for introducing the guide wire structure into a lumen.
This is because the two-guide wire structure shown in FIGS. 1a to
1c allows curvature in only one plane, so that steering the
structure in three dimensions requires the user to twist the
structure about its longitudinal axis, for example by using a
catheter to which the necessary torque can be applied. However, if
more than two guide wires are provided it is possible to curve the
structure in any plane; three guide wires are sufficient for this
purpose.
[0067] Attention is now directed to FIGS. 8a to 8c, which
illustrate the use of a guide wire structure 80 which comprises two
guide wires 81 and 82 connected by a junction portion 83. As can be
seen, the junction portion 83 is pivotal about an axis located at
the proximal end of the portion 83, so that, as shown in FIG. 8a,
it can pivot to such an extent that it lies flat along the distal
end portion of guide wire 81. This is advantageous in that it makes
possible, or makes easier, movement of the portion 83 within a
catheter 84, not only where there is no loop present (as in FIG.
8c) but also when there is (as shown in FIG. 8a). In this
connection it is to be understood that the diameter of the catheter
84 would actually be substantially greater than that shown in these
Figures. It is also to be understood that instead of being joined
by a junction portion 83 of significant length, as illustrated, the
guide wires could alternatively be joined by a junction of
substantially no length, i.e. the ends of the guide wires could be
connected by a junction consisting, at least in substance of just a
pivot point.
[0068] FIG. 9 shows yet another guide wire structure in which a
similar pivoting action can be achieved. This comprises guide wires
91 and 92, having respective floppy tip portions 91a and 92a
connected to one another by a thread or highly flexible wire 93.
This thread or wire can be inserted into the portions 91a and 92a,
or attached to their surfaces.
[0069] FIGS. 10-13 illustrate a guide wire structure according to
the present invention. The guide wire structure includes a
continuous, unitary wire having a segment (which can be positioned
generally in the middle portion of the wire), which segment has a
bending moment of inertia which is lower than the bending moment of
inertia of the adjacent wire segments. For instance, the wire can
change in cross sectional shape or dimension at a location that is
not a terminal end, so as to provide a bending hinge.
[0070] The bending moment of inertia for a circular cross-section
can be calculated as .pi.r.sup.4/4, where r is the radius of the
cross-section. The bending moment of inertia for a rectangular
cross-section can be calculated as bh.sup.3/12, where b is the base
of the rectangle and h is the height. "Mechanics of Materials", A.
C. Ugural, 1991, McGraw Hill is incorporated herein by reference
for its disclosure related to bending of cross-sections.
[0071] FIG. 10 shows an embodiment of guide wire structure of the
present invention comprising a continuous, unitary wire 100 that
has varying cross sectional area along a portion of its length. In
this embodiment, the wire 100 can have a first segment 121 having a
generally circular cross section of nominal diameter D101 and a
length L101, a second segment 122 having a generally circular
cross-section of nominal diameter D102 and a length L102, and a
third segment 123 having a generally circular cross-section of
nominal diameter D103 and length L103. The wire 100 can also
include a tapered transition segment 110 having a conical shape and
a length L104 and extending between segment 121 and segment 123,
and a tapered transition segment 112 having a length L105 and
extending between segment 123 and segment 122.
[0072] The reduced diameter D103 of the third segment 123 relative
to the diameter D101 and the diameter D102 provides the third
segment 123 with a bending moment of inertia which is lower than
that of the segments 121 and 122. Accordingly, the wire 100 can
bend at the third segment 123 to provide a hinge, which hinge can
encompass the length L103 of third segment 123, as well as some or
all of the lengths L104 and L105 of segments 110 and 112. In one
embodiment, the hinge so formed can be an elastic hinge.
[0073] The wire 100 with it's associated hinge can be used in the
embodiment as described below, as well as in those methods
disclosed with reference to FIGS. 1-9 above, without the need for
attaching or otherwise joining two wires or using different
materials.
[0074] In one embodiment, the diameters D101 and D102 can be
between about 0.010 inch to about 0.035 inch, and more particularly
about 0.016 inch to about 0.020 inch. The third segment 123 can
have a diameter D103 of between 0.005 inch and about 0.010 inch,
and in one embodiment D 103 can be about 0.007 inch.
[0075] Each of L101 and L102 can be at least about 3 feet, and can
be between about 6 feet and about 12 feet. The combined length
lengths L101, L102, L103, L104, and L105 can be between about 7
feet and about 25 feet. In one embodiment, the lengths L101 and
L102 can be about equal, and their combined length can be at least
about 20 feet. Length L103 of the third segment can be between
about 0.100 inch to about 0.500 inch, and in one embodiment can be
about 0.300 inch. The length L104 and Length 105 can be about
equal, and can each be about 2 inches. Modification of the cross
section of the wire 100 at a location intermediate the ends may be
accomplished by any suitable process, such as by grinding, drawing,
or stamping wire 100.
[0076] In one embodiment, the reduced cross-section of the third
segment 123 can be formed by centerless grinding. A reduced
cross-section can be formed using a grinding machine such as a
TF-9CPG System 2000 Guide Wire Profile Grinder available from
Glebar Company of Franklin Lakes, N.J.
[0077] The wire 100 can be enclosed in one or more low friction
and/or lubricous sleeves. In FIG. 11, the first wire segment 121 is
enclosed in a sleeve 155, second wire segment 122 is enclosed in a
sleeve 159, and the third segment and the transition segments are
enclosed in a sleeve 157. The sleeves 155, 157, and 159 can be
formed of a low friction material, such as PTFE or polyester.
Indicators can be associated with the first and second wire
segments 121 and 122 so that the wire segments can be distinguished
when viewed through a camera or other optical device associated
with an endoscope or other medical device. For instance, the
indicators can be visual, and can employ different colors. In one
embodiment, the sleeves 155 and 159 can be provided in different
colors and/or with different patterns of markings. In FIG. 13,
sleeve 155 has a pattern of heavy, diagonally slanted marks, while
sleeve 159 has a pattern of lighter, non-slanted markings. The
marking colors and/or the background color of the sleeves can be
different to distinguish sleeve 155 from sleeve 159. Alternating
stripes of different colors can also be used to distinguish sleeve
155 from sleeve 159, and thus segment 121 from 122 as viewed
through a visualization device. Sleeve 157 can have yet another
color or pattern of colors to provide a visual indication of the
location of the third segment 123.
[0078] FIG. 11 illustrates the wire 100 bent at the third segment
123 to form a narrow wire loop for introduction into a body cavity.
In FIG. 11, the wire 100 is illustrated with a generally U-shaped
bend 150 with a radius R110 so that the wire does not kink upon
placement through a colonoscope working channel, does not form a
sharp point that can damage tissue upon placement in a body lumen,
and preferably does not substantially plastically deform. In one
embodiment, the radius R110 can be about 0.75 mm to about 1.5 mm,
and more particularly about 1 mm.
[0079] Suitable biocompatible materials from which such a wire can
be constructed include those mentioned from which the wires of
FIGS. 1-9 can be formed, including without limitation a
superelastic material such as nitinol. Other materials, such as
steel and alloys can also be used. One suitable material from which
wire 100 can be formed is Nitinol NDC SE508 available from Nitinol
Devices and Components, a Johnson & Johnson Company of Fremont,
Calif.
[0080] FIG. 12 illustrates alternative embodiments in which the
cross-section of the narrowed length 103 is not round. Different
cross sectional shapes may be formed, such as changing a round wire
to a flat rectangular cross section in FIG. 12a, an oval cross
section in FIG. 12b, or a square cross section in FIG. 12c. Other
cross-sectional shapes, such as triangular, hexangonal, or other
polygonal shapes may be employed. Preferential bending planes of
certain cross sectional shapes can be used for the purposes of
directing the U-loop of the wire. For instance, a rectangular,
oval, or triangular cross-section can be employed to direct bending
about a particular axis.
[0081] The guide wire structure with wire 100 of the present
invention can be used in place of the wire configurations shown in
FIGS. 1-9, as well as with the device illustrated in U.S. patent
application Ser. No. 10/406,020 filed Apr. 3, 2003, which
application is incorporated by reference herein. FIG. 13 is a
schematic illustration of the guide wire structure with wire 100 in
use with a medical device 300. Generally, medical device 300 can be
a flexible endoscope, such as a flexible colonosocope, or a device
such as is shown in the above referenced patent application.
[0082] Medical device 300 can include a handle 310, which is
positioned outside a patient, an elongate flexible body portion
330, and a distal end 320 which can be positioned in a patient,
such as in a patient's GI tract, with distal end 320 sized and
shaped to be advanced in the GI tract. The medical device can also
include a working channel 350 extending through the body portion
330 and opening at the distal end 320 of the device 300, a camera
360, light source 370, a camera lens wash nozzle/irrigation nozzle
380, a light source 392, and a light source 394. Suction can be
provided through working channel 350, if desired.
[0083] The guide wire with wire 100 of the present invention can be
positioned within the working channel 350 such that the U shaped
bend in third segment 123 is positioned in the patient's body, and
the ends of the guide wire extend through an access opening of the
handle 310. In FIG. 13, the ends of the guide wire are indicated by
numeral 221 (associated with first segment 121) and numeral 222
(associated with second segment 122).
[0084] The guide wire with wire 100 can be used generally as shown
in FIGS. 3A-3C to advance a device into a body lumen, such as the
GI tract. In FIG. 13, after the U shaped bend in the third segment
123 has been advanced through the working channel 350, the first
segment 121 is advanced through the working channel relative to
second segment 122, so that the first segment 121 takes on a
curvature having a radius of curvature greater than Radius of
curvature R110, as shown in FIG. 13. To advance the distal end 320
further into the patient, the operator can pull proximally on end
222 to move third segment 123 back into the working channel 350,
thereby leaving the relatively large radius of curvature loop in
first segment 121 in the body lumen and extending from the distal
end of the device 300. End 222 can then be held fixed, and end 221
can be advanced distally toward handle 310 so that additional
length of the first segment 121 is advanced distally out of working
channel 350, thereby advancing the relatively large radius of
curvature loop distally in the GI tract. Then, while holding end
222 stationary with respect to handle 310, end 221 can be pulled in
tension (proximally) while simultaneously pushing (distally) the
elongate body portion 330 distally along wire segments 121 and 122
in working channel 350, so that the distal end 350 moves forward
(distally) into the GI tract. Accordingly, the wire segments 121
and 122 serve as a track upon which the distal end 350 of device
300 can be advanced.
[0085] While the present invention has been illustrated by
description of several embodiments, it is not the intention of the
applicant to restrict or limit the spirit and scope of the appended
claims to such detail. Numerous other variations, changes, and
substitutions will occur to those skilled in the art without
departing from the scope of the invention. Moreover, the structure
of each element associated with the present invention can be
alternatively described as a means for providing the function
performed by the element. It will be understood that the foregoing
description is provided by way of example, and that other
modifications may occur to those skilled in the art without
departing from the scope and spirit of the appended claims.
* * * * *