U.S. patent number 5,386,828 [Application Number 08/108,177] was granted by the patent office on 1995-02-07 for guide wire apparatus with location sensing member.
This patent grant is currently assigned to SIMS Deltec, Inc.. Invention is credited to Theodore A. Johnson, Robert C. Owens.
United States Patent |
5,386,828 |
Owens , et al. |
February 7, 1995 |
Guide wire apparatus with location sensing member
Abstract
The invention is directed to a guide wire apparatus and a method
for detecting the location of a guide wire within the body of a
patient. The apparatus includes a guide wire with an
internally-housed sensing member. The guide wire assembly is
structured to provide the response, maneuverability and tactile
feel comparable to conventional guide wire devices. The apparatus
is useful in medical treatments and diagnoses such as angioplasty
or catheterization procedures, for detecting obstructions within a
blood vessel of a patient, and the like.
Inventors: |
Owens; Robert C. (Forest Lake,
MN), Johnson; Theodore A. (St. Paul, MN) |
Assignee: |
SIMS Deltec, Inc. (St. Paul,
MN)
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Family
ID: |
25213652 |
Appl.
No.: |
08/108,177 |
Filed: |
August 17, 1993 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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813881 |
Dec 23, 1991 |
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Current U.S.
Class: |
600/585; 600/13;
600/424; 604/164.13; 604/526 |
Current CPC
Class: |
A61B
5/06 (20130101); A61M 25/0127 (20130101); A61M
25/09 (20130101); A61B 5/062 (20130101); A61M
2025/09083 (20130101) |
Current International
Class: |
A61B
5/06 (20060101); A61M 25/01 (20060101); A61B
005/05 () |
Field of
Search: |
;128/772,657,658,737,653.1 ;604/158,164,280,282,166,170
;600/13 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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091577 |
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Oct 1983 |
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EP |
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320623 |
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Jun 1989 |
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EP |
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0355996 |
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Feb 1990 |
|
EP |
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WO88/00810 |
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Feb 1988 |
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WO |
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Primary Examiner: Pellegrino; Stephen C.
Assistant Examiner: Tucker; Guy V.
Attorney, Agent or Firm: Merchant, Gould, Smith, Edell,
Welter & Schmidt
Parent Case Text
This application is a continuation application of Ser. No.
07/813,881, filed Dec. 23, 1991, now abandoned.
Claims
What is claimed is:
1. A system suitable for invasive use and location determination in
a patient, comprising:
a guide wire having proximal, center and distal portions, and a
lumen therethrough;
a sensing member capable of detecting an externally-generated
electromagnetic energy field, the sensing member including a metal
core having distal, center and proximal sections, each section of
the metal core further having an associated cross section, with at
least a part of the associated cross section of the center section
being of smaller dimension than the associated cross section of the
distal and proximal sections, wherein said sensing member is housed
within the lumen of the guide wire, the center section of the metal
core is proximate to the center of the guide wire, and a current
conducting wire is wound in a first layer around said distal end of
said metal core to form a sensor element, and said sensor element
is located near the distal portion of the guide wire;
an externally-located means for generating a current within the
sensor element; and,
an externally-located means for detecting a current within the
sensor element which is adapted for electrical connection with the
sensor element.
2. A system according to claim 1, wherein the smaller dimension of
the center section of the metal core provides a resiliency which
mimics a resiliency of a guide wire without an internal sensor when
invasively used with a patient.
3. A system according to claim 1, wherein at least part of the
metal core comprises a stainless steel.
4. A system according to claim 3, wherein the metal core further
comprises iron.
5. A system according to claim 1, wherein the conducting wire is a
material selected from the group consisting of copper, palladium,
silver, gold, platinum, or any combination thereof.
6. A system according to claim 1, wherein the sensor element
further comprises a second layer of wire overlying said first
layer.
7. A system according to claim 1, wherein the sensing member is
coated with a flexible, non-toxic insulating material.
8. A system according to claim 7, wherein the sensing member is
coated with a polymer material.
9. A system according to claim 8, wherein the polymer material is a
polyester.
10. A system according to claim 8, wherein the polymer material is
polyethylene, polyurethane, polyvinyl chloride, polyamide or
tetrafluoroethylene.
11. A system according to claim 1, wherein the guide wire comprises
a coiled wire.
12. A system according to claim 1, wherein the detecting means
measures the amplitude of the signal generated in the sensor
element.
13. A system according to claim 1, wherein the detecting means
determines a phase transition of the signal generated in the sensor
element.
14. A method of locating a guide wire apparatus in the body of a
patient, comprising:
(a) inserting a guide wire apparatus into the body, said apparatus
being a combination of
(i) a guide wire having proximal, center and distal portions, and a
lumen therethrough; and
(ii) a sensing member housed within said lumen of the guide wire,
the sensing member including a metal core having distal, center and
proximal sections, each section of the metal core further having an
associated cross section, with at least a part of the associated
cross section of the center section being of smaller dimension than
the associated cross section of the distal and proximal sections,
wherein the center section of the metal core is proximate to the
center of the guide wire, and a current conducting wire is wound in
a first layer around said distal end of said metal core to form a
sensing element; said sensor element located near the distal
portion of the guide wire;
(b) advancing the guide wire apparatus to a location within the
body
(c) determining the location of the sensor element within the body
of the patient by generating and detecting a current within the
sensor element through application of an external magnetic
field.
15. A method according to claim 14, wherein the smaller dimension
of the center section of the metal core provides a resiliency for
the guide wire housing the sensing member which mimics a resiliency
of a guide wire without an internal sensor when inserted into the
patient.
16. A method according to claim 14, comprising the additional step
of sensing, by tactile response of the guide wire apparatus, the
physical character of a portion of the body into which the guide
wire apparatus is inserted, the tactile response being determined
in part by the construction of the sensing member.
17. A method according to claim 16, wherein the sensing step
includes locating an obstruction in a blood vessel of the
patient.
18. A guide device suitable for invasive use in a patient,
comprising:
a guide wire having proximal, center, and distal portions and a
lumen therethrough; and
a sensing member housed within the lumen of the guide wire, and
having distal, center and proximal sections, said center section of
said sensing member proximate said center portion of said guide
wire, each of said sections having an associated cross section, and
a current conductor sensor element means which is located on the
distal section for interacting with an externally-generated
electromagnetic field so as to provide a current in the current
conducting sensor element means, the associated cross section of
the center section having at least in part a smaller dimension than
the associated cross section of the distal and proximal
sections.
19. A guide device according to claim 18 wherein the smaller
dimension of the center section member is capable of providing at
least in part to the guide device a tactile response and
maneuverability comparable to that of a guide wire without an
internal sensor when invasively used in a patient.
20. A guide device according to claim 18 wherein the sensing member
comprises a metal core having distal, center and proximal sections;
and
a current conducting wire wound in a first layer around a part of
the distal section of the metal core to form the current conducting
sensor element means.
Description
BACKGROUND OF THE INVENTION
Catheters are used in conjunction with various procedures to
diagnose and treat systems of the body, particularly the vascular
system. Guide wires are used to aid in the insertion of catheters
into the body and to evaluate the vessel along which the catheter
will travel. In general, a guide wire is inserted into a body
system such as a blood vessel and the vessel is probed with the
guide wire. The catheter is slipped over the guide wire and the
guide wire is withdrawn. The catheter is then eased through the
vessel to the desired location.
For proper manipulation and control of the guide wire during
insertion, the operator must be able to tactilely feel the end of
the guide wire within the vessel. For selectively placing a guide
wire in a particular corridor of a body system such as a blood
vessel, guide wires with flexible end portions are employed.
J-shaped guide wires are particularly useful for maneuvering
through curves and junctures of branched portions of a body
system.
To position the guide wire at a particular location within the
body, it is useful to have a means of detecting the location of the
tip of the guide wire. To this end, guide wires may be marked at
intervals along their length, wound with a dense metal such as
platinum, gold or tungsten to provide radiopacity for detection by
fluoroscopy, or other such marking technique. At present, however,
there are no guide wires with self-contained sensor components that
would permit determination of the location of the guide wire tip
after it has been inserted into the patient without the use of
fluoroscopy.
It would be desirable to have a guide wire with an
internally-housed sensor for locating the distal section of the
guide wire within the body. It would also be desirable to design
such a guide wire to have the tactile response to enable the
operator to manipulate and sense the progress of the leading end of
the guide wire during insertion and placement in the body,
particularly through branched channels of a the cardiovascular
system.
Therefore, an object of the invention is to provide a guide wire
apparatus with an internally-housed sensor element for detection of
the guide wire position in the body, a further object is to provide
a guide wire with a sensor that has the tactile response of a
conventional non-sensor guide wire. Another object is to provide a
method of using the guide wire apparatus for detecting obstructions
in the body, as for example, the vascular system.
SUMMARY OF THE INVENTION
These and other goals are achieved by the present invention which
is directed to a guide wire apparatus which will allow
determination of its location when it is inserted within the body
of a patient, and a method for its use.
The guide wire apparatus of the invention includes a guide wire and
sensing member for detecting the location of the guide wire distal
end position in the body. The guide wire has a channel or lumen
extending at least part of its length, and proximal, center and
distal portions. The lumen of the guide wire is dimensioned to
facilitate insertion and housing of the sensing member.
The sensing member is an elongate metal core with proximal, center
and distal sections, and a sensor element. Preferably, the metal
core is tapered at the center section such that the diameter of
about the midpoint of the center section is narrower than both the
distal and proximal sections. The sensor element is formed by a
current conducting wire wrapped around at least part of the metal
core distal section. The sensing member may be coated with a
protective covering material.
The construction of the guide wire, the sensing member, or both,
provides the guide wire apparatus with a flexibility factor such
that the combination of the guide wire and sensing member results
in a guide wire apparatus with a tactile feel, response and
maneuverability within the body of a patient, particularly the
vascular system, comparable to that of conventional guide wires
without internally-housed sensors. Preferably, the desired tactile
response and maneuverability of the guide wire apparatus may be
provided by constructing the sensing member with a tapered area at
the center section of the metal core.
The invention may further include a means for generating and
measuring an electromagnetic current in the sensor element. The
generation is accomplished by an external means for producing an
electromagnetic energy field. The measurement is accomplished by an
electronic controller which measures the sensor current generated
by the field. The apparatus may further include means for
transmitting current (e.g., alternating current) to the
electromagnetic energy field generating means. In one embodiment,
the electronic controller may measure the intensity or amplitude of
the current in the sensor element. With this embodiment, the
location of the distal section of the guide wire within the body is
determined by detecting the strength or magnitude of the sensor
current as the external means for generating the field is moved
over the body (see, for example, U.S. Pat. No. 4,173,228 to Van
Steenwyk, the disclosure of which is incorporated herein by
reference). In an alternative embodiment, the electronic controller
may be designed to detect a phase transition of the sensor current
as the external means for generating the field is moved over the
approximate location of the guide wire distal section within the
body (see, for example, U.S. Pat. No. 4,905,698 to Strohl et al.,
incorporated by reference herein (issued Mar. 6, 1990), subject of
a Reexamination issued Oct. 1, 1991.
The invention further includes a method of detecting the location
of a guide wire and/or an obstruction in the body of a patient
using the guide wire apparatus described herein. The method
includes inserting the guide wire apparatus into the body of the
patient, advancing the apparatus to the desired site within the
body, and detecting the location of the sensor element of the guide
wire apparatus. An obstruction is sensed by the tactile response of
the guide wire as it is advanced within the body. The location of
the obstruction is determined by detecting the location of the
sensor element.
BRIEF DESCRIPTION OF THE DRAWINGS
Throughout the following views, reference numerals will be used on
the drawings, and the same reference numerals will be used
throughout the several views and in the description to indicate
same or like parts of the inventions.
FIG. 1 illustrates a fragmentary, cross-sectional side view of a
guide wire assembly in accordance with the present invention.
FIG. 2 is a fragmentary, cross-sectional view of the sensor element
illustrated in FIG. 1.
FIG. 3 is a depiction of the guide wire apparatus in use.
FIG. 4 is a fragmentary, cross-sectional side view of an
alternative guide wire assembly in accordance with the present
invention.
DETAILED DESCRIPTION OF THE INVENTION
The guide wire apparatus of the invention is made of a guide wire
portion, and a sensing member for locating the distal end of the
guide wire in the body.
The guide wire has proximal, center and distal portions, and a
lumen extending at least part of the length of the guide wire.
Preferably, the guide wire is a helically coiled wire with elongate
proximal and center portions, and a shorter distal portion. In the
coiled configuration, the guide wire may include an internal safety
wire, with a diameter of about 0.05 to 0.5 mm, preferably about
0.08 to 0.2 mm, extending the length of the guide wire and coupled
at the distal and proximal ends of the guide wire to prevent
longitudinal elongation of the coiled wire.
The distal portion of the guide wire is the leading end of the
guide wire and is constructed to be easily flexed. The distal
portion is the end of the guide wire to be inserted into the body
of a patient. Consequently, when the guide wire apparatus is
advanced within the body and encounters a peritoneal blood vessel,
the tip of the guide wire does not cause puncture or perforation of
the blood vessel wall. Preferably, the tip of the guide wire is
rounded. The resiliency of the distal portion also allows the guide
wire apparatus to be readily maneuvered through curves and branches
within the body system in which the apparatus is used. The proximal
and center portions of the guide wire are capable of flexing but
are comparatively stiffer than the distal portion. To provide these
differing levels of stiffness, the proximal and center portions of
the guide wire may be formed, for example, of more tightly coiled
wire than the distal portion, of wire that has less flexibility
than that forming the distal portion, or wire that has a larger
diameter than that of the distal portion.
Although there is no precise juncture between the proximal and
center portions, in general, these two portions of the guide wire
are approximately equal in length. The proximal and center portions
have a combined length effective for the distal portion of the
guide wire to reach a desired site within the body system being
examined. Preferably, the combined length of the proximal and
center portions is about 70 to 80 cm, more preferably about 75 cm.
The juncture between the center and distal portions of the guide
wire may be gradual or abrupt. The distal portion of the guide wire
has a length effective to facilitate maneuvering of the guide wire
by the operator through curves and branches of a body system. The
length of the distal portion of the guide wire is preferably about
0.5 to 3 cm long, more preferably about 1 to 2 cm long.
The distal or leading end of the guide wire may be of any shape
suitable to allow the guide wire to be inserted into the body of
the patient and advanced within the body system to the desired
site. The distal end may have a configuration that is straight,
J-shaped, L-shaped, and the like, with a J-shaped configuration
being preferred.
The sensing member of the guide wire apparatus includes a sensor
element formed of a current conducting wire wound around a metal
core. The metal core has a proximal, central and distal section. In
cross-section, the metal core may be flat, round, octagonal, or
other shape, and may be solid or hollow. Preferably, the metal core
is a solid wire.
The metal core of the sensing member may be made of any suitable
magnetically permeable metal material which will interact with the
electromagnetic field flux to cause a strong generated current
within the sensor element. Examples of suitable materials for the
metal core include iron, nickel, cobalt, manganese, chromium,
stainless steel, and the like, alone or in combination. Preferably,
the metal core is composed of a stainless steel that has magnetic
properties as a result of the presence of ferritic particles. A
suitable example would be an American Iron and Steel Institute
(AISI) 400 series stainless steel. The stainless steel core may
also be covered with an outer layer of iron to further enhance its
magnetic properties. In another embodiment, the metal core may have
a distal section formed of an iron core that is bonded to a
stainless steel core forming the center and proximal sections.
When the sensing member is assembled into the lumen of the guide
wire, the resulting guide wire apparatus possesses a level of
flexibility yet stiffness comparable to the response,
maneuverability and tactile feel of a guide wire without an
internal sensor housed therein, like those of the traditional or
conventional guide wire devices used in diagnostic and treatment
procedures. In particular, the guide wire apparatus has an
appropriate combination of stiffness and bendability to provide the
desired control and flexibility for use in medical applications,
such as angioplasty or catheterization procedures, for detecting
obstructions within a channel of a body organ such as a blood
vessel of a patient.
It is preferred that the desired tactile response and
maneuverability is provided in part by the construction of the
guide wire, the sensing member, or both. Preferably, the metal core
of the sensing member is constructed to provide the guide wire
apparatus with the desired flexibility. For example, the center
section of the metal core of the sensing member may be tapered so
that the diameter of about its mid-point is less than the diameter
of either the distal or proximal sections of the metal core. The
tapered configuration of the metal core provides the sensing member
with a flexibility or bendability factor to provide, at least in
part, the desired level of flexibility and stiffness in the guide
wire apparatus.
A current conducting wire is preferably wound around the distal
section of the metal core in one or more overlying layers,
preferably two layers, to form the sensor element. The current
conducting wire is composed of a fine wire with a diameter of about
0.04 to 0.08 mm, with about 0.05 mm being preferred. The distal
section of the metal core is of a length suitable to accommodate an
effective amount of the conducting wire to form the sensor element.
In a preferred embodiment, the sensor element includes about
250-300 winds, more preferably about 280 winds, of the conducting
wire in a double layer over the distal section. The current
conducting wire may be composed of any suitable material capable of
conducting a current, as for example, the noble metals such as
copper, silver, gold, platinum, palladium, or other like material,
copper being most preferred. The ends of the current conducting
wire are connected by two lead wires to the electronic controller.
Preferably, the ends of the current conducting wire extend along
the length of the metal core and connect with the lead wires at the
proximal end of the apparatus.
To protect the sensor element from damage, the sensing member may
be coated with a protective covering material, preferably a
flexible, non-toxic, insulating material. Suitable coating
materials include polymer materials such as polyurethane,
polyethylene, polyvinyl chloride, nylon (polyamide), teflon
(Tetrafluoroethylene (TFE) fluorocarbon polymers, an example of
which is polytetrafluoroethylene (trademarked as Teflon, a
registered mark of The du Pont Company, Wilmington, Del.
(polyperfluorolefin), or a polyester material. The polymer material
may be applied by any suitable method which will provide a thin
covering layer, preferably about 0.05 to 0.2 mm thick, more
preferably about 0.1 to 0.15 mm thick, on the surface of the
sensing member without altering or damaging the sensor element.
The diameters of the proximal, center and distal sections of the
metal core are adapted to fit the sensing member having an applied
coating layer within the lumen of the guide wire. In a preferred
embodiment, the diameter of the distal section of metal core with a
layer of conducting wire is about 0.3 to 1 mm, more preferably
about 0.5 to 0.8 mm; and the diameter of the proximal core section
is about 0.2 to 0.8 mm, more preferably about 0.3 to 0.5 mm. In a
preferred embodiment of the sensing member, the diameter of the
mid-point of the center core section of the metal core is about 0.1
to 0.4 mm, more preferably about 0.2 to 0.3 mm.
The sensing member is housed within the lumen of the guide wire,
preferably with the proximal end of the sensing member co-terminus
with the proximal end of the guide wire. The lengths of the metal
core and of the lumen of the guide wire are sufficient to place the
sensor element in the area of the center portion of the guide wire
at or near the adjoining distal portion.
A first embodiment of the guide wire assembly in accordance with
the invention is illustrated in FIGS. 1 through 3, and designated
generally by the numeral 100. In general, the guide wire assembly
100 includes a J-shaped guide wire 110 and an internally-housed
sensing member 120.
Referring to FIG. 1, guide wire 110 includes a proximal portion
114, a center portion 116, and a distal portion 118, a proximal end
115, a distal end 117. Guidewire 110 also includes a lumen 112 into
which sensing member 120 is inserted. As shown in FIG. 2, sensing
member 120 includes a metal core 122 that has a proximal section
124, a center section 126, and a distal section 128. As depicted,
sensor element 132 is formed of a current conducting wire 134 wound
around distal section 128 of metal core 122 in a double layer. As
further illustrated, protective coating layer 135 covers sensing
member 120 to protect sensor element 132 from damage. It is
understood, however, that sensing member 120 need not be covered
with protective coating layer 135.
Sensing member 120 is located within guide wire 110 so that distal
section 128 with sensor element 132 are positioned in the area of
center portion 116 at or near adjoining distal portion 118 of guide
wire 110. A safety wire 113 may be housed within lumen 112 and
attached to guide wire 110 at proximal end 115 and distal end
117.
In the first embodiment depicted in FIGS. 1 and 2, center section
126 of metal core 122 is tapered so that the diameter of about its
mid-point 130 is less than the diameter of either distal section
128 or proximal section 124 of the metal core 122. As illustrated
in FIG. 4, in a second embodiment of a guide wire assembly,
designated generally by the numeral 200, metal core 222 of sensing
member 220 is not constricted at center section 226. Center section
226 provides a gradation in diameter from distal section 228 to
proximal section 224 of metal core 222.
In use, as depicted in FIG. 3, guide wire apparatus 100 is inserted
into the body of a patient 150, and advanced according to standard
placement procedures to a desired location 152 where sensor element
132 may be detected. For example, guide wire apparatus 100 may be
inserted into a blood vessel and advanced until an obstruction or
constriction is sensed by touch, and the location of distal portion
118 of guide wire 110 detected. As depicted, current conducting
wire 134 is connected by two lead wires 136, 137 to an electronic
controller 140. To detect sensor element 132 of guide wire
apparatus 100 in situ in the body, electronic controller 140 is
activated to generate an alternating current to external field
generator 146, positioned against the skin 154 of patient 150,
which produces an electromagnetic (electromagnetic) energy field.
The intersection of the electromagnetic energy field and sensor
element 132 may be determined by measurement of the variation of
signal amplitude as the field generator 146 nears the location of
sensor element 132. The construction and arrangement of the
electromagnetic energy field relative to sensor element 132, and
the function for the signal amplitude determination follow the
methods of Van Steenwyk in U.S. Pat. No. 4,173,228, the disclosure
of which is incorporated herein by reference.
The interaction of the electromagnetic energy field and sensor
element 132 may alternatively be determined by measurement of the
phase transition of the current generated in sensor element 132 as
the electromagnetic energy field moves over sensor element 132. In
this embodiment, the construction and arrangement of the
electromagnetic energy field relative to sensor element 132 and the
function of the phase transition follow the method of Strohl et al.
in U.S. Pat. No. 4,905,698 to Strohl et al.), the disclosure of
which is incorporated by reference herein. Briefly, when field
generator 146 is positioned to produce an electromagnetic energy
field perpendicular to the long axis of sensor element 132, phase
transition can be measured. As field generator 146 approaches
sensor element 132, a voltage of a certain phase is produced in
sensor element 132 by field generator 146. When field generator 146
is directly above sensor element 132, a phase transition occurs
whereby no voltage is momentarily produced. As field generator 146
passes beyond sensor element 132, voltage is again produced but is
completely out of phase with the earlier voltage or with the
alternating current operating field generator 146. The phase
transition produces a series of visual and/or audio signals to
indicate location.
The construction of guide wire 110 and/or sensing element 132,
advantageously provides a guide wire apparatus 100 that can
internally house a location sensing device yet retain the
flexibility and tactile response needed for maneuvering within
branched systems, such as the vascular system, within the body of a
patient similar to traditional guide wires. The guide wire
apparatus of the invention, in general, is particularly useful in
angioplasty or catheterization procedures, for detecting
obstructions within a branched channels of a body system such as a
blood vessel of a patient, and determining the location of the
obstruction and distal end portion of the guide wire within such a
body system.
The invention has been described with reference to various specific
and preferred embodiments and techniques. However, it should be
understood that many variations and modifications may be made while
remaining within the spirit and scope of the invention.
* * * * *