U.S. patent application number 11/475840 was filed with the patent office on 2007-01-25 for method of and apparatus for navigating medical devices in body lumens.
Invention is credited to Walter M. Blume, Jeffrey M. Garibaldi.
Application Number | 20070021731 11/475840 |
Document ID | / |
Family ID | 36600387 |
Filed Date | 2007-01-25 |
United States Patent
Application |
20070021731 |
Kind Code |
A1 |
Garibaldi; Jeffrey M. ; et
al. |
January 25, 2007 |
Method of and apparatus for navigating medical devices in body
lumens
Abstract
A guide wire combined with a catheter or medical device for
moving through a body lumen to a desired position in the body with
the aid of an applied magnetic field. The guide wire is provided
with a magnet on its distal end that can be oriented or oriented
and moved by the application of a magnetic field to the magnet. A
catheter or other medical device can be advanced over the guide
wire. Once the medical device is in its desired position, the
magnet can be withdrawn through the lumen of the catheter.
Alternatively, a guide wire with a magnet on its distal end can be
docked at the distal end of a catheter or medical device and can be
oriented, or oriented and moved by the application of a magnetic
field.
Inventors: |
Garibaldi; Jeffrey M.; (St.
Louis, MO) ; Blume; Walter M.; (Webster Groves,
MO) |
Correspondence
Address: |
HARNESS, DICKEY, & PIERCE, P.L.C
7700 BONHOMME, STE 400
ST. LOUIS
MO
63105
US
|
Family ID: |
36600387 |
Appl. No.: |
11/475840 |
Filed: |
June 27, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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09200055 |
Nov 25, 1998 |
7066924 |
|
|
11475840 |
Jun 27, 2006 |
|
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PCT/US98/02835 |
Feb 17, 1998 |
|
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|
11475840 |
Jun 27, 2006 |
|
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|
08969165 |
Nov 12, 1997 |
5931818 |
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11475840 |
Jun 27, 2006 |
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Current U.S.
Class: |
604/510 ;
600/585; 604/164.13 |
Current CPC
Class: |
A61M 25/0127 20130101;
A61M 2025/09075 20130101; A61M 25/09 20130101; A61M 2025/09083
20130101 |
Class at
Publication: |
604/510 ;
604/164.13; 600/585 |
International
Class: |
A61M 31/00 20060101
A61M031/00; A61M 5/178 20060101 A61M005/178; A61M 25/00 20060101
A61M025/00 |
Claims
1.-20. (canceled)
21. A method of navigating a medical device having a proximal end
portion, a distal end portion, and a magnetically responsive
element disposed on the distal end portion of the medical device,
the method comprising: introducing the distal end portion of the
medical device having the magnetically responsive element into a
subject's body; applying a magnetic field to the area of the
subject in which the medical device is located, the magnetic field
being effective for orienting the magnetically responsive element
on the distal end portion of the medical device with the magnetic
field, wherein the application of the magnetic field is controlled
to allow an operator to guide the distal end portion of the medical
device in a desired direction; and applying a subsequent magnetic
field to the area of the subject in which the medical device is
located, the subsequent magnetic field being effective for pulling
the magnetically responsive element on the distal end portion of
the medical device to advance the medical device in the desired
direction.
22. The method of claim 21 further comprising the steps of
iteratively applying a magnetic field effective for orienting the
magnetically responsive element on the distal end portion of the
medical device with the magnetic field to re-orient the distal end
in a desired direction, and a subsequent magnetic field effective
for pulling the magnetically responsive element on the distal end
portion of the medical device to advance the medical device in the
desired direction, to incrementally guide the medical device to a
desired location within a subject's body.
23. The method of claim 21 further comprising the steps of
advancing a catheter over the medical device, the catheter having a
passage therethrough in which the medical device is received, such
that the catheter may be advanced over the medical device to guide
the catheter to where the distal end portion of the medical device
is located within the subject's body.
24. The method of claim 21 further comprising the steps of
advancing an endoscope over the medical device, the catheter having
a passage therethrough in which the medical device is received,
such that the endoscope may be advanced over the medical device to
guide the endoscope to where the distal end portion of the medical
device is located within the subject's body.
25. The method of claim 21 further comprising the step of pushing
the proximal end portion of the medical device to assist in
advancing the medical device in the desired direction.
26. The method of claim 23 further comprising the step of
retracting the medical device from the catheter once the catheter
has been guided to a desired location within the subject's
body.
27. The method of claim 24 further comprising the step of
retracting the medical device from the endoscope once the endoscope
has been guided to a desired location within the subject's
body.
28. The method of claim 22 wherein the medical device is inserted
within the vasculature of a subject's body.
29. The method of claim 22 wherein the magnetic field is applied
from a location external to the subject.
30. A method of navigating a catheter device having a passageway
therein through a subject's body, the method comprising:
introducing the distal end portion of the catheter device into a
subject's body; introducing the distal end portion of a medical
device into the passage in the catheter device, the medical device
having a proximal end portion, a distal end portion, and a
magnetically responsive element disposed on the distal end portion
of the medical device; applying a magnetic field to the area of the
subject in which the medical device is located, the magnetic field
being effective for orienting the magnetically responsive element
on the distal end portion of the medical device with the magnetic
field, wherein the application of the magnetic field is controlled
to allow an operator to guide the distal end portion of the medical
device in a desired direction; applying a subsequent magnetic field
to the area of the subject in which the medical device is located,
the subsequent magnetic field being effective for pulling the
magnetically responsive element on the distal end portion of the
medical device to advance the medical device in the desired
direction; and advancing the catheter device, if necessary, over
the medical device received within the passage in the catheter
device.
31. The method of claim 30 further comprising the steps of
iteratively applying a magnetic field effective for orienting the
magnetically responsive element on the distal end portion of the
medical device with the magnetic field to re-orient the distal end
in a desired direction, and a subsequent magnetic field effective
for pulling the magnetically responsive element on the distal end
portion of the medical device to advance the medical device in the
desired direction, to incrementally guide the medical device to a
desired location within a subject's body.
32. The method of claim 30 further comprising the step of pushing
the proximal end portion of the medical device to assist the
subsequent magnetic field in advancing the medical device in the
desired direction.
33. The method of claim 30 wherein the catheter device is advanced
over the medical device by pushing the proximal end portion of the
catheter device to advance the catheter device towards the distal
end portion of the medical device.
34. The method of claim 31 further comprising the step of
retracting the medical device from the catheter once the catheter
device has been guided to a desired location within the subject's
body.
35. The method of claim 30 wherein the medical device is inserted
within the vasculature of a subject's body.
36. The method of claim 34 wherein the medical device comprises a
guide wire having a distal end portion including a core wire on
which the magnetically responsive element is disposed, the distal
end portion being sufficiently flexible adjacent the magnetically
responsive element to allow the wire to flex in response to a
magnetic field applied to the magnetically responsive element.
37. The method of claim 30 wherein the magnetic field is applied
from a location external to the subject.
38. A method of navigating a medical device having a proximal end
portion, a distal end portion, and a magnetically responsive
element disposed on the distal end portion of the medical device,
the method comprising: introducing the distal end portion of the
medical device having the magnetically responsive element into a
subject's body; applying a magnetic field to the area of the
subject in which the medical device is located, the magnetic field
being effective for orienting the magnetically responsive element
on the distal end portion of the medical device with the magnetic
field, wherein the application of the magnetic field is controlled
to allow an operator to guide the distal end portion of the medical
device in a desired direction; and pushing the proximal end of the
medical device, while the magnetic field is being applied to orient
the magnetically responsive element on the distal end portion of
the medical device with the magnetic field, to advance the medical
device in the desired direction.
39. The method of claim 38 further comprising the steps of
iteratively applying a magnetic field effective for orienting the
magnetically responsive element on the distal end portion of the
medical device with the magnetic field to re-orient the distal end
in a desired direction, and pushing the proximal end of the medical
device to advance the medical device in the desired direction, to
incrementally guide the medical device to a desired location within
a subject's body.
40. The method of claim 39 further comprising the steps of
advancing a catheter over the medical device, the catheter having a
passage therethrough in which the medical device is received, such
that the catheter may be advanced over the medical device to guide
the catheter to where the distal end portion of the medical device
is located within the subject's body.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application is a continuation in part of PCT
application Serial No. PCT/US98/02835 filed Feb. 17, 1998.
FIELD OF THE INVENTION
[0002] This invention relates to a method of, and apparatus for,
navigating medical devices in body lumens, such as in blood
vessels, the trachea, the gastrointestinal tract, or the urinary
tract.
BACKGROUND OF THE INVENTION
[0003] Many diagnostic and therapeutic medical procedures require
navigating a medical device to a particular location through lumens
in the body. For example, procedures such as cardiac
catheterizations and interventional neuroradiology procedures
involve the introduction of medical devices through the arteries;
bronchoscopies involve the introduction of medical devices through
the trachea; endoscopies and colonoscopies involve the introduction
of instruments through the gastrointestinal tract; and
urethroscopies involve the introduction of medical devices through
the urinary tract.
[0004] Numerous methods and apparatus have been developed for
introducing medical devices in the body. Many of these methods
employ guide wires for remotely controlling the orientation of the
tip of the medical device as it is advanced in the body lumen.
These guide wires typically have a bend in their distal ends, the
tip is rotated until the tip is properly oriented, and the wire is
then advanced. It is a difficult and tedious process to steer a
medical device remotely with a guide wire since the orientation of
the guide wire is difficult to control. Thus, these procedures can
be prolonged, which increases the risk to the patient and fatigues
the physician.
[0005] It has been proposed to guide medical devices in the body
with magnets, see Yodh, Pierce, Weggel, and Montgomery, A New
Magnetic System, for `Intravascular Navigation`, Medical &
Biological Engineering, Vol. 6, No. 2, pp. 143-147 (March 1968),
incorporated herein by reference. This article proposes a
magnetically tipped catheter that is steered within the body by an
externally applied magnetic field. However, the magnet in this
proposed device is attached to the catheter which can impair the
ability to control the magnet. Moreover, there is no provision for
removing the magnet and leaving the catheter or other medical
device in place. Thus, only one such catheter can be directed to a
given position because the magnetic field acting on one magnet will
also act on the other magnets in the vicinity.
SUMMARY OF THE INVENTION
[0006] The methods and apparatuses of the present invention involve
magnetically guiding a medical device through a lumen in the body.
Generally, according to the method of this invention, a magnet is
provided on the end of a guide wire and an externally applied
magnetic field orients the magnet in the body lumen. The magnet can
be advanced through the body lumen by manipulating the magnetic
field or by pushing the guide wire.
[0007] According to a first embodiment of this invention, a
catheter may be disposed over a guide wire having a magnet on its
distal end. The guide wire and catheter combination is introduced
into a body lumen through a natural or surgically formed opening.
Once in the body the guide wire and catheter combination is
navigated through the body lumen by applying a magnetic field,
which acts on the distal end of the guide wire, orienting it.
Typically, the guide wire is advanced slightly ahead of the
catheter at a branch in the body lumen, and a magnetic field is
applied to orient the tip of the guide wire, and the guide wire is
advanced in the direction of the tip which is oriented into the
selected branch. The guide wire can be advanced by the application
of the magnetic field, by pushing at the proximal end, or by both.
The catheter is then advanced over the guide wire. This process is
repeated until the distal end of the catheter is at its desired
location. Once the distal end of the catheter is in the desired
position, the magnet can be withdrawn through the lumen of the
catheter by pulling on the tether. Treatment, such as drug therapy
or embolizing agents, can then be passed through the catheter.
[0008] According to a second embodiment of this invention, a guide
wire with a magnet on the tip may be docked at the distal end of
the lumen inside a catheter or other medical device. The guide wire
and catheter combination is introduced into a body lumen through a
natural or surgically formed opening. Once in the body lumen, the
guide wire and catheter combination is navigated through the body
lumen by applying a magnetic field, which acts upon the
magnet-tipped guide wire in the catheter, orienting it. The
catheter is advanced by pushing the guide wire. Once the distal end
of the catheter is in the desired location, the guide wire can be
withdrawn through the lumen of the catheter by pulling on the guide
wire. Treatment, such as drug therapy or embolizing agents, can
then be passed through the catheter.
[0009] The methods of the various embodiments of this invention,
and the guide wire of the various embodiments of this invention,
facilitate quick, easy and accurate positioning of a catheter or
other medical device via a body lumen. Once the catheter is
properly positioned, it can be used during a diagnostic or
therapeutic procedure, either directly or as a passage for other
medical devices.
[0010] These and other features and advantages will be in part
apparent and in part pointed out hereinafter.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 is a longitudinal cross-sectional view of a guide
wire and catheter combination constructed according to the
principles of a first embodiment this invention;
[0012] FIG. 2 is a plan view of the guide wire of the first
embodiment;
[0013] FIG. 3 is an enlarged cross-sectional view of the distal tip
of the guide wire;
[0014] FIG. 4 is an enlarged cross sectional view the distal end of
a first alternate construction of the guide wire of the first
embodiment, using a socket to secure the magnet;
[0015] FIG. 5 is an enlarged cross sectional view of the distal end
of a second alternate construction of the guide wire of the first
embodiment, using a collar to secure the magnet.
[0016] FIG. 6 is an enlarged cross-sectional view of a third
alternate construction of the distal section of the guide wire;
[0017] FIG. 7 is an enlarged cross-sectional view of a fourth
alternate construction of the distal section of the guide wire;
[0018] FIG. 8 is a side elevation view of the distal section of a
fifth alternate construction of the guide wire of the first
embodiment with a portion broken away to show details of the
construction;
[0019] FIG. 9 is a side elevation view of the distal end section of
a sixth alternate construction of the guide wire of the first
embodiment;
[0020] FIG. 10 is a side elevation view of the distal end section
of a seventh alternate construction of the guide wire of the first
embodiment;
[0021] FIG. 11 is a side elevation view of the distal section of an
eighth alternate construction of the guide wire of the first
embodiment;
[0022] FIG. 11a is an enlarged side elevation view of the eighth
alternate construction of the distal end section, with a portion
broken away to show details of the construction;
[0023] FIG. 12 is a side elevation view of the distal section of a
ninth alternate construction of the guide wire of the first
embodiment;
[0024] FIG. 12a is a side elevation view of the distal section of
the third alternate construction of the guide wire, in a magnetic
field;
[0025] FIG. 13 is a side elevation view of a tenth alternate
construction of the distal section of the guide wire;
[0026] FIG. 13a is a side elevation view of a tenth alternate
construction of the distal tip of the guide wire, in a magnetic
field;
[0027] FIG. 14 is a longitudinal cross-sectional view of the guide
wire and endoscope combination constructed according to the
principles of the first embodiment of this invention;
[0028] FIG. 15 is a longitudinal cross-sectional view of a guide
wire and catheter combination according a second embodiment of this
invention;
[0029] FIG. 16 is a longitudinal cross-sectional view of a guide
wire and catheter combination with the guide wire partially
withdrawn from the lumen of the catheter; and
[0030] FIG. 17 is a side elevation view of a guide wire and biopsy
device according to the principles of the present invention.
[0031] Corresponding reference numbers indicate corresponding parts
throughout the several views of the drawings.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0032] A guide wire and magnet combination constructed according to
the principles of a first embodiment of this invention is indicated
generally as 20 in FIG. 1. The guide wire and catheter combination
20 comprises a guide wire 22 and a catheter 24. The guide wire 22
comprises a wire 26, which is preferably made of nitinol, which is
highly flexible and resists kinking, although the guide wire could
be made of some other suitable material. A magnet 28 is mounted on
the distal end 30 of the wire 26. This magnet may either be a
permanent magnet or a permeable magnetic material. A permanent
magnet is easier to orient under the application of a magnetic
field, as described below, but a permeable magnetic material is
easier to pull under the application of a magnetic field.
[0033] In the preferred embodiment, the magnet 28 is made of NdFeB
(neodymium-iron-boron) or samarium cobalt and is sized to respond
to the magnetic field that will be applied to orient the guide wire
22 in the body lumen and to be retracted through the catheter 24.
The magnet 28 is preferably elongate so that it can orient the tip
of the guide wire 22 in the presence of an applied magnetic field.
Magnets of about 0.3 mm (0.02 inches) to about 0.7 mm (0.03 inches)
in diameter, and about 1 mm (0.04 inches) to 1.5 mm (0.06 inches)
long are sufficiently large for use in navigating a guide wire.
[0034] As shown in FIGS. 2 and 3, the magnet 28 is preferably a
cylindrical body 34 with an axial bore 36 therethrough. The distal
end of the wire 26 extends through the bore 36, and is secured with
a bead 38 of adhesive on the distal side of the magnet 28. The bead
38 also provides a rounded head on the distal end 30 of the guide
wire 22.
[0035] A first alternate construction of the guide wire 22 of the
first embodiment is indicated generally as 40 in FIG. 4. The guide
wire 40 is similar in construction to guide wire 22, comprising
wire 42, having a proximal end (not shown) and a distal end 44. A
mounting body 46, having a socket 48 therein, is attached to the
distal end 44 of the wire. A magnet 50 is mounted in the mounting
body. The magnet can be secured in the mounting body with adhesive,
or the socket 48 can be crimped to secure the proximal end of the
magnet 50 in the socket 48.
[0036] A second alternate construction of the guide wire 22 of the
first embodiment is indicated generally as 60 in FIG. 5. The guide
wire 60 is similar in construction to guide 22, comprising a wire
62 having a proximal end (not shown) and a distal end 64. A
mounting collar 66 is attached to the distal end 64 of the wire 62.
A magnet 68 is mounted on the mounting collar 66. The magnet 68 can
be secured to the mounting collar 66 by adhesive or by fusion.
[0037] A third alternate construction of the guide wire 22 is
indicated generally as 70 in FIG. 6. The guide wire 70 is similar
in construction to guide 22, comprising a wire 72 having a proximal
end (not shown) and a distal end 74, and a magnet 76 mounted on the
distal end of the wire 72. The magnet 76 is preferably a
cylindrical body with an axial bore 78 therethrough. The distal end
of the wire 24 extends through the bore 78, and is secured with a
bead 80 of adhesive on the distal side of the magnet 76. The bead
80 also provides a rounded head on the distal end of the guide wire
22. There is a tapering collar 82 on the wire 26 proximal to the
magnet 76. The collar 82 facilitates withdrawing the magnet 76
through the distal end of the catheter 24. The collar can be made
of a platinum or some other non-magnetic radio opaque material so
that the position of the end of the guide wire can be easily
located with x-ray or fluoroscopic imaging equipment.
[0038] A fourth alternative construction of a guide wire 22 is
indicated generally as 90 in FIG. 7. The guide wire 90 is similar
in construction to guide wire 22, comprising a wire 92 having a
proximal end (not shown) and a distal end 94, and a magnet 96 on
the distal end of the wire 92. The magnet 96 is preferably a
cylindrical body with an axial bore 98 therethrough. The distal end
of the wire 24 extends through the bore 98, and is secured with a
bead 100 of adhesive on the distal side of the magnet 96. The bead
100 also provides a rounded head on the distal end of the guide
wire 90. The guide wire 90 includes a sheath 102, made of flexible
polyurethane tubing, extending over the wire 92. The sheath 102
preferably has the same outside diameter as the magnet 96, to
smoothly slide in the lumen of the catheter, and to help prevent
excessive movement of the guide wire 90 within the lumen. The
sheath 102 is preferably secured to the proximal end of the magnet
96 with an adhesive, such as SICOMET 40 available from Tracon.
[0039] A fifth alternate construction of the guide wire of the
first embodiment is indicated generally as 110 in FIG. 8. Guide
wire 110 comprises a wire 112 having a proximal end (not shown) and
a distal end 114. The wire 112 is preferably made of nitinol, which
is highly flexible and resists kinking, although it could be made
of some other suitable material. A magnet 116, which can either be
a permeable magnet or a permanent magnet, is secured on the distal
end 114. A permanent magnet is easier to orient under the
application of a magnetic field, as described below, but a
permeable magnetic material is easier to pull under the application
of a magnetic field.
[0040] The magnet 116 is preferably made of NdFeB
(neodymium-iron-boron) or samarium cobalt and is sized to respond
to the magnetic field that will be applied to orient the distal tip
of the guide wire 110 in the body lumen and to be retracted through
the lumen of the catheter or other medical device. The magnet 116
is preferably elongate so that it can orient the distal tip of the
guide wire 110 in the presence of an applied magnetic field.
Magnets of about 0.3 mm (0.02 inches) to about 0.7 mm (0.03 inches)
in diameter, and about 1 mm (0.04 inches) to 1.5 mm (0.06 inches)
long are sufficiently large for use in navigating a guide wire.
[0041] As shown in FIG. 8, the magnet 116 is preferably a
cylindrical body. A magnetic or non-magnetic sleeve 118, made of a
suitable sheet material or wire, covers the magnet 76 and extends
over the distal end 114 of the guide wire 110, securing the magnet
on the wire. In this preferred embodiment shown in FIG. 8 the
sleeve 118 is made from a thin plastic tube, which is can be
secured over the magnet and the distal end of the guide wire, with
an adhesive, or more preferably, by heat shrinking.
[0042] A sixth alternate construction of the guide wire of the
first embodiment is indicated generally as 120 in FIG. 9. Guide
wire 120 comprises a wire 122 having a proximal end (not shown) and
a distal end 124. The wire 122 is preferably made of nitinol, which
is highly flexible and resists kinking, although it could be made
of some other suitable material. A magnet 126, which can either be
a permeable magnet or a permanent magnet, is secured on the distal
end 124, for example with adhesive. A permanent magnet is easier to
orient under the application of a magnetic field, as described
below, but a permeable magnetic material is easier to pull under
the application of a magnetic field.
[0043] The magnet 126 is preferably made of NdFeB
(neodymium-iron-boron) or samarium cobalt and is sized to respond
to the magnetic field that will be applied to orient the distal tip
guide wire 120 in the body lumen and to be retracted through the
lumen of the catheter or other medical device. The magnet 126 is
preferably elongate so that it can orient the distal tip of the
guide wire 120 in the presence of an applied magnetic field.
Magnets of about 0.3 mm (0.02 inches) to about 0.7 mm (0.03 inches)
in diameter, and about 1 mm (0.04 inches) to 1.5 mm (0.06 inches)
long are sufficiently large for use in navigating a guide wire.
[0044] As shown in FIG. 9, the magnet 126 is preferably a
cylindrical body. A sleeve 128, made of wire, covers the magnet 126
and extends over the distal end 124 of the wire 122, helping to
secure the magnet on the wire. In this preferred embodiment shown
in FIG. 9, the sleeve 128 is a coil of platinum wire, the proximal
end of which is secured to the wire 122 proximal to the distal end
124, and the distal end of which is secured to the magnet 126. The
coil improves the axial stiffness of the distal end while leaving
the guide wire flexible in other directions to permit magnetic
navigation. The coil also improves the radiopacity of the end of
the guide wire so that it can be seen on x-ray and fluoroscopic
images. The coil is secured to the wire 122 and to the magnet 126
with adhesive. The adhesive preferably fills the spaces between the
turns of the coil around the magnet 126, so that the surface is
smooth.
[0045] A seventh alternate construction of the guide wire of the
first embodiment is indicated generally as 130 in FIG. 10. Guide
wire 130 comprises a wire 132 having a proximal end (not shown) and
a distal end 134. The wire 132 is preferably made of nitinol, which
is highly flexible and resists kinking, although it could be made
of some other suitable material. A magnet 136, which can either be
a permeable magnet or a permanent magnet, is secured on the distal
end 132, for example with adhesive. A permanent magnet is easier to
orient under the application of a magnetic field, as described
below, but a permeable magnetic material is easier to pull under
the application of a magnetic field.
[0046] The magnet 136 is preferably made of NdFeB
(neodymium-iron-boron) or samarium cobalt and is sized to respond
to the magnetic field that will be applied to orient the distal tip
guide wire 130 in the body lumen and to be retracted through the
lumen of the catheter or other medical device. The magnet 136 is
preferably elongate so that it can orient the distal tip of the
guide wire 130 in the presence of an applied magnetic field.
Magnets of about 0.3 mm (0.02 inches) to about 0.7 mm (0.03 inches)
in diameter, and about 1 mm (0.04 inches) to 1.5 mm (0.06 inches)
long are sufficiently large for use in navigating a guide wire.
[0047] As shown in FIG. 10, the magnet 136 is preferably a
cylindrical body. A coil 138 of platinum wire is disposed over the
distal end portion of the wire 132. The proximal end of the coil is
attached to the wire 132 proximal to the distal end, and the distal
end of the coil is attached to the proximal end of the magnet 136.
The coil improves the axial stiffness of the distal end while
leaving the guide wire flexible in other directions to permit
magnetic navigation. The coil also improves the radiopacity of the
end of the guide wire so that it can be seen on x-ray and
fluoroscopic images. The coil 98 is secured to the wire 92 and to
the magnet 96 with adhesive. A sleeve covers the magnet 136 and
extends over the coil 138 an the distal end 134 of the wire 130,
helping to secure the magnet and the coil on the wire. In this
preferred embodiment shown in FIG. 10, the sleeve 140 is a tube of
a flexible plastic material, that is secured with an adhesive, or
more preferably by heat shrinking.
[0048] An eighth alternate construction of the guide wire of the
first embodiment is indicated generally as 150 in FIGS. 11 and 11a.
Guide wire 150 comprises a wire 152, having a proximal end (not
shown) and a distal end 154. The wire 152 is preferably made of
nitinol, which is highly flexible and resists kinking, although it
could be made of some other suitable material. The wire 152 tapers
toward the distal end 154. The portion of the wire 152 adjacent the
distal end is surrounded by a magnetic coil 156.
[0049] A ninth alternate construction of the first embodiment of a
guide wire according to the principles of this invention is
indicated generally as 160 in FIGS. 12 and 12a. Guide wire 160
comprises a wire 162 having a proximal end (not shown) and a distal
end 164. Instead of a single magnet on the distal end of the wire,
as in the first embodiment, guide wire 160 has a series of spaced
magnets 166 on the distal end portion 168 of the wire 162. The
magnets 166 each preferably have a generally cylindrical body, with
an axial bore 170 extending therethrough. The distal portion 54 of
the wire 56 extends through the bores 60, and the magnets 52 are
secured to the wire 56 in spaced apart relation with adhesive.
[0050] The magnets 166 are preferably made from NdFeB, and have a
diameter of 2 mm (0.08 inches) and are 4 mm (0.16 inches) long. The
magnets 166 are preferably spaced over the distal 5 cm (2 inches)
of the guide wire 160, and are spaced 1 cm (0.4 inches) on center.
Of course some other size magnets and/or different magnet spacing
could be used. Moreover the spacing of the magnets does not have to
be equal. This third alternate construction is particularly useful
for an electrophysiology catheter where the magnetic fields could
pull or shape the guide wire 160 to the heart wall, thereby guiding
the electrophysiology catheter over the guide wire against the
heart wall.
[0051] As shown in FIG. 12a, upon the application of a magnetic
field, the magnets 166 on the distal end portion 164 of the guide
wire 160 cause the guide wire to assume a particular shape dictated
by the field. Thus by controlling the applied magnetic field, the
shape of the distal portion of the guide wire can be controlled,
facilitating the navigation through, or shaping to, the body lumen.
The guide wire 160 can be advanced by pulling with a magnetic force
on the magnets 166, or the proximal end can be manually pushed. A
magnetic pulling force could also be used to hold the catheter with
guide wire to the wall of a body lumen.
[0052] A tenth alternate construction of the first embodiment of a
guide wire constructed according to the principles of the present
invention is indicated generally as 180 in FIGS. 13 and 13a. The
guide wire 180 comprises a wire 182, having a proximal end (not
shown) and a distal end 184. Instead of the single magnet on the
distal end of the wire, or a plurality of magnets on the distal end
portion of the wire, the distal end portion 186 of guide wire 180
is made from a magnetic material.
[0053] The distal end portion 186 is preferably about 0.25 mm (0.01
inches) in diameter, and about 1 cm (0.4 inches) long. The distal
end portion can be made of a permeable magnetic material such as a
steel or a magnetic stainless steel wire, or a steel or a magnetic
stainless steel braid.
[0054] As shown in FIG. 13a, upon the application of a magnetic
field, the distal end portion 186 of the guide wire 180 assumes a
particular orientation dictated by the field. Thus by controlling
the applied magnetic field, the orientation and/or shape of the
distal portion 186 of the guide wire 180 can be controlled,
facilitating the navigation through the body lumen. The guide wire
180 can be advanced by magnet force on the distal end portion 186,
or the proximal end can be pushed. The magnetic field can also
function to selectively stiffen the distal end portion 186 of the
guide wire, to facilitate navigation through the body lumen. This
allows the guide wire 182 to be designed with the minimum amount of
stiffness to overcome static friction when applying an axial
pushing force on at the proximal end. Sufficient stiffness for
navigation can be provided by applying a magnetic field to the
distal tip.
[0055] As shown in FIG. 1, the catheter 24 is preferably of
conventional construction, having a proximal end 100, a distal end
202, and a lumen 204 extending therebetween. The catheter 24 can be
made of polyurethane tubing, or some other suitable material. The
size of the catheter 24 depends upon where in the body it will be
introduced, and how it will be used. For example, for use in the
blood vessels in the brain, the catheter might have an outside
diameter of about 0.7 mm (0.03 inches), an inside diameter of about
0.6 mm (0.02 inches), and a length of about 2 m (6.6 feet). Of
course, medical devices other than catheters can be used with the
guide wire, for example an endoscope where the guide wire is
inserted through its working channel. These devices would typically
include a lumen extending all or partly along the length of the
device that passes over the guide wire so that the device follows
the guide wire. One of the guide wires of the present invention can
be introduced into a body lumen, such as a blood vessel, and
navigated to its desired location by the controlled application of
magnetic fields. The application of a magnetic field allows the
operator to steer the distal end of the guide wire by orienting the
distal end of the guide wire to the desired direction of travel.
The guide wire can be advanced using the magnetic field to pull the
magnet on the distal end of the guide wire, or the guide wire can
be advanced by pushing the proximal end. As the guide wire
advances, the catheter 24 or other medical device can be advanced
over the guide wire, until the catheter or medical device is in its
desired location.
[0056] Once the distal end 202 of the catheter 24 has been placed
in its desired location, the guide wire can be left in place, or if
the magnet is sufficiently small, the guide wire can be withdrawn
through the lumen 204 of the catheter and out the proximal end
200.
[0057] The magnetic articulation of the distal end of the guide
wire eliminates the need to provide a permanent bend in the guide
wire in order to navigate through branches in body lumens. The
straight configuration of the guide wires permitted by the present
invention permits faster and easier navigation in straight sections
of the body lumen and reduces unintentional diversion down branches
of the lumen.
[0058] As shown in FIG. 14, one of the guide wires of this
invention can be used to navigate an endoscope 300 through a body
lumen, such as a colon. The endoscope 300 has a lumen 302 extending
therethrough. A magnetic field is applied to orient the magnet on
the distal end of the guide wire with the magnetic field. The
endoscope 300 can then be advanced over the guide wire, the lumen
302 sliding over the guide wire. The guide wire is preferably
incrementally advanced, and the endoscope is then advanced over the
guide wire, until the distal end of the endoscope 300 reaches its
desired location.
[0059] A guide wire and catheter combination constructed according
to a second embodiment of this invention is indicated generally as
400 in FIGS. 15 and 16. The guide wire and catheter combination 400
comprises guide wire 402 and catheter 404. The guide wire 402
comprises a wire 406, preferably made of nitinol, which is highly
flexible and resists kinking, although the guide wire could be made
of some other suitable material. A magnet 408 is mounted on the
distal end 410 of the wire 406. This magnet may either be a
permanent magnet or a permeable magnetic material. A permanent
magnet is easier to orient under the application of a magnetic
field, as described below, but a permeable magnetic material is
easier to pull under the application of a magnetic field.
[0060] In the preferred embodiment, the magnet 408 is made of NdFeB
(neodymium-iron-boron) or samarium cobalt and is sized to respond
to the magnetic field that will be applied to move the guide wire
402 through the body lumen. The magnet 408 is preferably elongate
so that it can orient the tip of the guide wire 402 in the presence
of an applied magnetic field. Magnets of about 0.3 mm (0.02 inches)
to about 0.7 mm (0.03 inches) in diameter, and about 1 mm (0.04
inches) to 1.5 mm (0.06 inches) long are sufficiently large for use
in navigating a guide wire.
[0061] As shown in FIG. 16, the magnet is preferably a cylindrical
body with an axial bore 412 therethrough. The distal end of the
wire 410 extends through the bore 412, and is secured with a bead
414 of adhesive on the distal side of the magnet 408. The bead 414
also provides a rounded head on the distal end of the guide wire
402. Of course instead of magnet 408, the guide wire 402 could have
a plurality of spaced magnets on the distal end portion similar to
guide wire 160, described above, or the distal end portion of the
guide wire could be made of a flexible magnetic material similar to
guide wire 180.
[0062] The catheter 404 is preferably of conventional construction,
having a proximal end 416, a distal end 418, and a lumen 420
extending therebetween. The catheter 404 can be made of
polyurethane tubing, or some other suitable material. The size of
the catheter 404 depends upon where in the body it will be
introduced, and how it will be used. For example, for use in the
blood vessels in the brain, the catheter might have an outside
diameter of about 0.7 mm (0.13 inches), an inside diameter of about
0.6 mm (0.11 inches), and a length of about 2 m (6.5 feet).
[0063] The guide wire 402 is adapted to fit inside the lumen 420,
and "dock" with the catheter 404. To facilitate this, the distal
end of the lumen 420 has a restriction or stricture 422 for
engaging the distal end of the guide wire 422. This restriction or
stricture is preferably formed by a annular flange 924 on ring 426
provided on the distal end of the catheter, although it could be
some other reduction in the lumen that can be engaged by the guide
wire. The ring 426 can be made of tantalum.
[0064] The guide wire and catheter combination 400 can be
introduced into a body lumen, such as a blood vessel, and navigated
to its desired position by the controlled application of magnetic
fields. The application of a magnetic field allows the operator to
steer the distal end of the guide wire 402 by orienting the distal
end of the guide wire to the desired direction of travel. The guide
wire 402 can be advanced using the magnetic field to pull the
magnets on the distal end or the guide wire can be advanced by
pushing the proximal end. As the guide wire 402 advances, the
catheter 404 can be advanced.
[0065] Once the distal end 418 of the catheter 404 has been placed
in its desired location, the guide wire 402 can be withdrawn
through the lumen 420, and out the proximal end 416.
[0066] As shown in FIG. 17, the guide wire 412 can be used to
navigate a biopsy tool 428 through a body lumen such as a kidney.
The biopsy tool 428 has a lumen 430 therein. The distal end of the
guide wire 402 is adapted to fit into the lumen 430 and "dock" with
the biopsy tool. A magnetic field is applied to orient the magnet
408 inside the lumen 430 of the biopsy tool 428. The biopsy tool
428 can then be advanced, in the desired direction either by
pushing the proximal end of the guide wire 402, or pulling the
distal end of the guide wire with the magnetic field. When the
biopsy tool 428 has been advanced to its desired location, the
guide wire 402 can be withdrawn.
[0067] The guide wires of either embodiment can be used to deliver
catheter or other medical devices to locations within the body
accessible via a body lumen. For example the guide wire could be
used to navigate a device for retrieval of man made objects stents,
or body made objects e.g. stones. The high degree of articulation
of the tip provides the control needed to capture and recover such
objects.
Operation
[0068] In operation, one of the guide wires 22, 40, 50, 60, 70, 90,
110, 120, 130, 150, 160, or 180 of the first embodiment and an
associated catheter or other medical device is introduced through a
natural or surgically formed opening in a body lumen. A magnetic
field is applied to orient the distal tip within the body lumen.
The magnetic field can also be used to advance the distal tip of
the guide wire, or the guide wire can be pushed to advance the
guide wire in the body lumen. As the guide wire is incrementally
advanced the catheter can be advanced over the guide wire. Once the
distal end of the catheter is in its desired position, the magnet
is removed from the catheter by pulling the guide wire to withdraw
the magnet through the lumen of the catheter.
[0069] Because the magnet on the guide wire can be removed from the
treatment site, multiple catheters can be directed in the same
general area to facilitate a medical procedure with independent
control of the catheters.
[0070] In operation, the guide wire 402 is inserted into the lumen
of the catheter 404 (or other medical device) and the guide wire
and catheter combination 400 of the second embodiment is introduced
through an opening in a natural or surgically formed opening in a
body lumen. A magnetic field is applied to orient the magnet 408 on
the proximal end of the guide wire 402, inside the catheter 404.
The guide wire and catheter are then advanced, either by applying a
magnetic field, or by pushing the distal end of the guide wire.
Once the distal end 418 of the catheter is in its desired position,
the guide wire 402 is removed from the catheter 404 by pulling the
guide wire 402 to withdraw it from the lumen 420 of the
catheter.
[0071] Once the catheter 24 or 404 is in position it can be used
for the administration of drug therapy or to perform a medical
procedure or it can be used as a guide to insert medical devices to
the area surrounding the distal end of the catheter to perform a
medical procedure.
[0072] Because the magnet on the guide wire can be removed from the
treatment site, multiple catheters can be directed in the same
general area to facilitate a medical procedure with independent
control of the catheters. Of course, the magnet could be left in
place within the catheter, if desired.
* * * * *