U.S. patent number RE34,502 [Application Number 07/848,827] was granted by the patent office on 1994-01-11 for steerable catheter.
Invention is credited to Wilton W. Webster, Jr..
United States Patent |
RE34,502 |
Webster, Jr. |
January 11, 1994 |
Steerable catheter
Abstract
A catheter, which is adapted to be inserted into a body lumen,
comprises a symmetrical cylindrical control handle, an elongate
tubular catheter body, and a flexible catheter tip having a lumen
offset from the axis of the catheter tip. The control handle
comprises a housing having a piston chamber at its distal end. A
piston is mounted in the piston chamber and is afforded lengthwise
movement. The proximal end of the catheter body is fixedly attached
to the distal end of the piston. A puller wire is attached to the
housing and extends through the piston, through and coaxial with
the catheter body and into the offset lumen of the catheter tip
where it is attached to the wall of the catheter tip. Lengthwise
movement of the piston relative to the housing results in
deflection of the catheter tip.
Inventors: |
Webster, Jr.; Wilton W.
(Baldwin Park, CA) |
Family
ID: |
23042325 |
Appl.
No.: |
07/848,827 |
Filed: |
March 11, 1992 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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Reissue of: |
273048 |
Nov 18, 1988 |
04960134 |
Oct 2, 1990 |
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Current U.S.
Class: |
607/125;
607/145 |
Current CPC
Class: |
A61M
25/0147 (20130101); A61N 1/056 (20130101); A61M
2025/015 (20130101) |
Current International
Class: |
A61M
25/01 (20060101); A61N 1/05 (20060101); A61N
001/05 () |
Field of
Search: |
;128/783,784,785,786,642,800,772,790 ;603/95 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Kamm; William E.
Assistant Examiner: Getzow; Scott M.
Attorney, Agent or Firm: Christie, Parker & Hale
Claims
What is claimed is:
1. A steerable catheter comprising:
a flexible elongated catheter body having proximal and distal ends
and a first lumen;
a flexible catheter tip fixedly attached to the distal end of the
catheter body, said tip comprising a second lumen, the axis of the
second lumen being offset from the axis of the tip;
a control handle at the proximal end of the catheter body, said
control handle comprising:
a housing having proximal and distal ends and a piston chamber at
its distal end;
a piston having proximal and distal ends and a longitudinal bore
therethrough mounted in the piston chamber of the housing and
moveable longitudinally within the piston chamber, wherein the
proximal end of the catheter body is fixedly attached to the distal
end of the piston; and
means proximal to the piston, for securing the proximal end of a
puller wire to the housing;
an elongated puller wire having a proximal end fixedly attached to
the securing means at a location proximal to the piston chamber,
said puller wire extending through the bore of the piston, the
first lumen of the catheter body and into the second lumen of the
catheter tip, said puller wire further comprising a distal end
fixedly attached to the catheter tip; and
whereby longitudinal movement of the piston relative to the housing
results in deflection of the catheter tip.
2. A catheter as claimed in claim 1 wherein the puller wire is
generally coaxial with the catheter body.
3. A catheter as claimed in claim 1 wherein the distal end of the
piston extends out of the distal end of the housing and comprises a
thumbrest to facilitate manual movement of the piston relative to
the housing.
4. A catheter as claimed in claim 1 wherein the piston comprises a
circumferential notch along its length, and the control handle
comprises an O-ring positioned within the notch for forming a
generally water-tight seal between the piston and the housing.
5. A catheter as claimed in claim 1 wherein the piston comprises a
slot along a portion of its length, and the control handle
comprises a pin which extends from the housing into the slot.
6. A catheter as claimed in claim 1 wherein the housing comprises a
transversely extending bore proximal to the piston, and the
securing means comprises an anchor positioned within the bore, said
anchor having a hole through which the puller wire extends, and
wherein the anchor is rotatable to thereby wedge and secure the
proximal end of the puller wire between the anchor and the
housing.
7. A steerable electrode catheter comprising:
a flexible, elongated catheter body having proximal and distal ends
and a lumen;
a flexible catheter tip fixedly attached to the distal end of the
catheter body, said tip comprising at least one electrode and at
least one lumen having an axis offset from the axis of the tip;
a control handle at the proximal end of the catheter body, said
control handle comprising:
a housing having proximal and distal ends and a piston chamber at
its distal end and a connector chamber at its proximal end;
a rotary connector attached to the proximal end of the housing, the
rotary connector comprising:
a male plug having a terminal for electrical connection with each
electrode; and
a contact which extends into the connector chamber electrically
connected to each terminal;
a piston having proximal and distal ends and a longitudinal bore
therethrough mounted in the piston chamber of the housing and
moveable longitudinally within the piston chamber, wherein the
proximal end of the catheter body is fixedly attached to the distal
end of the piston; and
means proximal to the piston, for securing the proximal end of a
puller wire to the housing;
an elongated puller wire having a proximal end secured to the
securing means, said puller wire extending through the bore of the
piston, through the first lumen of the catheter body in generally
coaxial relation to the catheter body and into the offset lumen of
the catheter tip, said puller wire further comprising a distal end
fixedly attached to the catheter tip whereby longitudinal movement
of the piston relative to the housing results in deflection of the
catheter tip; and
an electrode lead associated with each electrode, each electrode
lead having a distal end attached to an electrode and extending
through the catheter tip, catheter body, and piston and into the
connector chamber of the housing wherein the electrode lead is
attached to a contact of the rotary connecter.
8. A catheter as claimed in claim 7 wherein the distal end of the
piston extends out of the distal end of the housing and comprises a
thumbrest to facilitate manual movement of the piston relative to
the housing.
9. A catheter as claimed in claim 7 wherein the piston comprises a
circumferential notch along its length and the control handle
comprises an O-ring positioned within the notch for forming a
generally water-tight seal between the piston and the housing.
10. A catheter as claimed in claim 7 wherein the piston comprises a
slot along a portion of its length and the control handle comprises
a pin which extends from the housing into the slot.
11. A catheter as claimed in claim 7 wherein the housing comprises
a transversely extending bore proximal to the piston and the
securing means comprises an anchor positioned within the bore, said
anchor having a hole through which the puller wire extends, and
wherein the anchor is rotatable to thereby wedge and secure the
proximal end of the puller wire between the anchor and housing.
12. A catheter as claimed in claim 7 wherein the rotary connector
comprises a flexible core between the contacts and the male plug.
.Iadd.
13. A steerable catheter comprising:
a flexible, elongated catheter body having proximal and distal ends
and a first lumen formed therein in coaxial relation with the
catheter body;
a flexible catheter tip portion fixedly attached to the distal end
of the catheter body, said tip portion having proximal and distal
ends and a second lumen wherein the axis of the second lumen is
offset from the axis of the tip portion;
an elongated puller wire having a proximal end located at the
proximal end of the catheter body and a distal end at the catheter
tip portion, the puller wire being disposed in and extending
through the first lumen in coaxial relation with the catheter body
and into the second lumen, the distal end of the puller wire being
secured to the catheter tip portion, wherein the catheter further
comprises means for supporting the puller wire in the first lumen
in coaxial relation with the catheter body, whereby longitudinal
movement of the puller wire results in deflection of the catheter
tip portion; and
means located at the proximal end of the catheter body for
controlling longitudinal movement of the puller wire. .Iaddend.
.Iadd.
14. A catheter as claimed in claim 13, wherein the means for
supporting the puller wire in the first lumen such that the puller
wire is coaxial with the catheter body comprises a sheath around
the puller wire, said sheath further providing lubricity for the
puller wire in the first lumen. .Iaddend.
Description
FIELD OF THE INVENTION
This invention relates to steerable catheters for use in a body
lumen, and more specifically to a rotatable electrode catheter
having a steerable tip.
BACKGROUND OF THE INVENTION
Catheters have been in common use in medical practice for many
years. They are used to probe locations inside a body lumen which
are otherwise unreachable without surgery. A catheter is first
inserted into a major vein or artery, or other body lumen which is
near the body surface. The catheter is then guided to the area of
concern by further inserting it into the body lumen. As medical
knowledge increases, catheterizations have become more complicated
and more exacting. In many situations the ability to control the
exact position and orientation of the catheter tip largely
determines how useful the catheter is.
The body of a catheter is long and tubular. The problem of control
over such a device has resulted in catheters which are generally
rigid and preformed into specific shapes. This is exemplified by U.
S. Pat. No. 3,485,234 to Stevens, which describes a method for
making a catheter is any desired shape. However, given the
complexity of body lumens, each preformed catheter can only reach
certain areas. Thus, for many examinations, multiple catheters are
needed, either inserted together or each one in turn. In either
case, this greatly adds to the complexity of the procedure and
create additional risk for the patient.
Flexible catheters having steerable tips are also known. Such
catheters have control handles at their proximal ends controlling
the tips. U. S. Pat. No. 4,586,923 to Gould describes many of
these. The mechanisms described involve control handles which are
asymmetrical. This results in the control handle being less
effective when it is rotated, as the controls are no longer in a
convenient position to use. Control of the catheter is therefore
limited, as the user is not free to rotate the device without
losing some control over it.
A catheter often has probes of some kind, e.g., electrodes, on its
tip in order to deliver stimuli and/or take measurements within he
body lumen. In such a catheter, the probe is electrically connected
to an instrument capable of generating the stimuli or recording
and/or interpreting signals received by the probes. The connection
to this additional instrument generally involves the use of
multiple wires which plug into separate sockets, as shown in U. S.
Pat. No. 4,603,705 to Speicher, or the use of a single multiple pin
plug which fits into a corresponding multiple pin socket. In either
case, if the catheter is rotated, the connections must be unplugged
and reset, since they otherwise restrict the movement of the
catheter. This problem further increases the risks mentioned above
in regards to multiple catheters. Each catheter has its own
connections, all of which will need to be reset as the catheters
are manipulated. The additional loss of data flow and increased
procedure length further increase the risk to the patient.
SUMMARY OF INVENTION
This invention therefore provides a steerable catheter having a
symmetrical control handle which can be rotated freely while in
use. The catheter comprises an elongated catheter body having a
first lumen which extends through the catheter body. The catheter
tip is fixedly attached to the distal end of the catheter body. The
catheter tip comprises a lumen which is offset from the axis of the
catheter tip.
A control handle is attached to the proximal end of the catheter
body. The control handle comprises a generally symmetrical housing
having a piston chamber at its distal end. A piston having a
longitudinal and preferably axial bore is mounted within the
chamber and is manually movable lengthwise within the chamber. The
proximal end of the catheter body is fixedly attached to the distal
end of the piston.
An elongated puller wire is fixedly attached to the control handle
housing at a location proximal to the piston and extends through
the bore of the piston, through and preferably coaxial with the
lumen of the catheter body and into the off-axis lumen of the
catheter tip. The distal end of the puller wire is fixedly attached
to the wall of the catheter tip. In such an arrangement, movement
of the piston relative to the housing causes movement of the puller
wire relative to the catheter body and the catheter tip, resulting
in deflection of the catheter tip.
In a preferred embodiment of the invention, the catheter tip
comprises one or more electrodes. Lead wires extend from the
control handle through the lumen of the catheter body, preferably
through a lumen in the catheter tip, and preferably a second
off-axis lumen, and are there electrically connected to the
electrodes.
In the control handle, the electrode leads extend through the bore
of the piston and through the housing of the control handle to an
electrical connector for connecting the leads to a electrical
stimulator and/or recorder. In such an embodiment, it is preferred
that the connector is a rotary connector to afford rotatable
movement to the control handle and catheter without breaking
electrical contact with the stimulator and/or recorder.
BRIEF DESCRIPTION OF THE DRAWINGS
These and other features and advantages of the present invention
will be better understood by reference to the following detailed
description when considered in conjunction with the accompanying
drawings wherein:
FIG. 1 is a longitudinal cross-sectional external view of a
preferred electrode catheter constructed in accordance with the
present invention;
FIG. 2 is an enlarged view of the junction of the catheter body and
the catheter tip;
FIG. 3 is an enlarged cross-sectional view of the catheter tip
showing the attachment of the puller wire; and
FIG. 4 is an enlarged longitudinal cross-sectional view of the
control handle.
DETAILED DESCRIPTION
FIG. 1 illustrates a preferred electrode catheter constructed in
accordance with the present invention. The electrode catheter 10
comprises an elongated catheter body 11 having proximal and distal
ends, a catheter tip 12 at the distal end of the catheter body 11,
and a control handle 13 at the proximal end of the catheter body
11.
The catheter body 11 comprises an elongated tubular construction
section having a single lumen 15. The catheter body 11 is flexible,
i.e., bendable, but substantially non-compressible along its
length. The catheter body 11 may be of any suitable construction
and made of any suitable material. A presently preferred
construction comprises a nylon tube surrounded by braided stainless
steel with a polyurethane coating.
The length and diameter of the catheter body 11 are not critical
and may vary according to the application. For the electrode
catheter shown in the accompanying drawing, a length of about 48
inches, an outer diameter of about 0.09 inch, and an inner
diameter, i.e. lumen diameter, of about 0.03 to about 0.04 inches
is presently preferred.
The catheter tip 12 comprises a short section of flexible tubing 16
having a pair of nonoverlapping, e.g., side-by-side first and
second lumens 17 and 18 which are off-axis, i.e., are not coaxial
with catheter tip 12. The tubing 16, may be made of any suitable
materials, and is preferably more flexible than the catheter body.
A presently preferred material for the catheter tip is polyurethane
having a D55 hardness.
The diameter of the catheter tip 12 is not critical, but is
preferably about the same as, or slightly smaller, than the
diameter of the catheter body 11. The length of the catheter tip 12
is likewise not critical. The embodiment shown, the length of the
catheter tip 12 is about two inches.
Along the length of the flexible tubing 16, there are a plurality
of electrodes 21. The electrodes 21 are in the form of metal rings,
the outer diameter of the electrodes 21 being about the same as the
outer diameter of the flexible tubing 16 so that the electrodes 21
form a smooth, continuous surface with the outer surface of the
flexible tubing 16. A rounded end electrode 22 is positioned at the
distal end of the catheter tip 12.
A preferred means for attaching the catheter tip 12 to the catheter
body 11 is shown in FIG. 2. The proximal end of the catheter tip 12
comprises an outer circumferential notch 26 and the distal end of
the catheter body 11 comprises an inner circumferential notch 27.
The notches 26 and 27 are sized to allow the notched proximal end
of the catheter tip 12 to be snugly inserted into the notched
distal end of the catheter body 11. The catheter tip 12 is then
fixedly attached to the distal end of the catheter body 11 by glue
or the like. As shown, the lumen 15 of the catheter body 11 is in
communication with both off-axis lumens 17 and 18 of the catheter
tip 12.
A puller wire 30, preferably made of stainless steel, extends from
the control handle 13 through the lumen 15 of the catheter body 11
and into the first lumen 17 of the catheter tip 12. The puller wire
30 extends into the first lumen 17 of the catheter tip 12 to a
position near the distal end of the catheter tip 12 and is fixedly
attached to the wall of the flexible tubing 16. The puller wire 30
is preferably surrounded by a teflon sheath 31 or the like for
lubricity and to keep the puller wire 30 generally coaxial with the
catheter body 11. In the first lumen, the sheath 31 is swaged,
i.e., thinned to smaller wall thickness to accommodate the smaller
first lumen 17 of the catheter tip 12.
A preferred means for attaching the puller wire 30 to the wall of
the catheter tip is shown in FIG. 3 and comprises a short piece of
tubular stainless steel 32, e.g., hypodermic stock, which is fitted
over the distal end of the puller wire 30 and crimped to fixedly
secure the puller wire 30. The distal end of the tubular stainless
steel 32 is fixedly attached, e.g., by welding, to a stainless
steel crosspiece 33 such as stainless steel ribbon or the like. The
crosspiece 33 sits within a notch 34 in the wall of the flexible
tubing 16 which extends into the first lumen 17. This provides an
opening through the wall of the flexible tubing 16 into the first
lumen 17. The stainless steel crosspiece 34 is larger than the
opening and, therefore, cannot be pulled through the opening. The
portion of the notch 34 not filled by the crosspiece 33 is filled
with glue or the like, preferably a polyurethane glue harder than
the material of the flexible tubing 16. Rough edges, if any, of the
crosspiece 34 are polished to provide a smooth, continuous surface
with the outer surface of the flexible tubing 16.
Electrode lead wires 36 extend from the control handle 13 through
the lumen 15 of the catheter body 11 and into the second lumen 18
of the catheter tip 12. The lead wires 36 are attached to the
electrodes 21 and 22 by any conventional technique.
With reference to FIG. 4, the control handle 13 comprises a
generally cylindrical housing 40 having open chambers at each end.
A piston chamber 41 is at the distal end of the housing 40, and a
connector chamber 42 is at the proximal end of the housing 40.
There is an axial passageway 43 and an offset passageway 44 leading
from the piston chamber 41 to the connector chamber 42. The housing
is generally symmetrical about its longitudinal axis. This allows
the control handle to be freely rotated without altering
convenience or quality of control.
A cylindrical piston 46 is slidably disposed within and generally
coaxial with the piston chamber 41. The piston 46 comprises a
circumferential O-ring notch 47 which carries an O-ring 48 to
provide a snug, watertight fit between the piston 46 and the wall
of the piston chamber 41.
The piston 46 further comprises a slot 49 extending along a portion
of its length proximal to the O-ring notch 47. When the piston 46
is disposed within the piston chamber 41, a pin 51, e.g. a set
screw, extends from the wall of the housing 40 into the slot 49.
The piston 46 can slide distally until the pin 51 engages the
proximal end of the slot 49 and proximally until the pin 51 engages
the distal end of the slot 49. Thus, the pin 51 and slot 49 limit
lengthwise movement of the piston 46 within the piston chamber 41
and prevent the piston 46 from being pushed out of the piston
chamber 41.
The piston 46 has an axial bore 52 along its length. The diameter
of the axial bore 52 is about the same as the outer diameter of the
catheter body 11. The catheter body extends into the axial bore 52
and is fixedly attached, e.g. by glue, to the piston 46.
The distal end of the piston 46 extends beyond the distal end of
the housing 40, in order that it may be manually controlled by the
user. An annular thumbrest 54 is attached to the distal end of the
piston 46 to facilitate lengthwise movement of the piston 46.
The puller wire 30 extends through the axial bore 52 of the piston
46 and is fixedly attached to the housing 40 by means of an anchor
56. The anchor 56 extends into a transverse hole in the portion of
the housing 40 between the connector chamber 42 and piston chamber
41. The anchor 56 blocks the axial passageway 43, but not the
offset passageway 44. The anchor 56 is rotatable within the hole,
but fits snugly so that it does not rotate freely.
The anchor 56 comprises a transversely extending hole 57 which can
be rotated into alignment with the axial passageway 43. To secure
the puller wire 30 to the anchor 56, the puller wire 30 is passed
through the axial passageway 43 and transversely extending hole 57
in the anchor 56 and the anchor 56 is rotated to wedge the puller
wire 30 between the anchor 56 and the wall of the housing 40.
Tension on the puller wire 30 can be adjusted by rotation of the
anchor 56.
In use, the catheter tip can be curved or bent to steer the tip
into a branching lumen, e.g., a branching blood vessel, by gripping
the control handle housing and moving the piston distally out of
the piston chamber by pushing outwardly on the thumbrest. Because
the catheter body is attached to the piston and the puller wire is
attached to the housing, this action causes movement of the puller
wire relative to the catheter body and tip, effectively pulling the
catheter tip proximally toward the catheter handle. Because the
puller wire is offset from the axis of the tip, the tip bends in
the direction of the offset, as shown in FIG. 1, to accommodate the
force exerted on it.
In use, catheters are often rotated slowly as the catheter is
passed through a body lumen, e.g. artery. The rotation facilitates
passage around bends in the body lumen. The symmetrical design of
the handle provides the unique advantage of allowing the handle to
be rotated without affecting or altering the manner in which the
handle is gripped and manipulated by the physician. Such a design
thus facilitates the smooth manipulation of the catheter.
Another unique advantage is provided by maintaining the puller wire
in coaxial relation with the catheter body. Often a catheter is
inserted into a body lumen and is bent or curved because the body
lumen curves or bends. In such a situation, a puller wire which is
offset from the axis of the catheter body tends to predispose the
catheter in a curved shape wherein the puller wire lies on the
inside of the curve. Such a catheter acts like a preformed
catheter, i.e. a catheter having a preformed shape, and resists
rotation. This is because in such an arrangement, the length of the
puller wire is less than the on-axis length of the catheter. This
means that rotation of the catheter one-half turn requires the
puller wire to move to the outside of the curve. To do this,
however, the on-axis length of the catheter must be compressed or
reduced relative to the length of the puller wire, Thus, before the
tip rotates, the handle must be rotated sufficiently to build
sufficient torque to supply the energy required to compress the
catheter body. The result is that rotation of the tip lags far
behind rotation of the handle which makes control of the tip
difficult.
By maintaining the puller wire in coaxial relation with the
catheter body in accordance with the present invention, the length
of the puller wire and on-axis length of the catheter body are the
same, whether the catheter body extends around a curve or not. In
this arrangement, less energy is required for rotation of the
catheter tip. This allows the tip to be more responsive to rotation
of the handle and therefore more easily controlled.
The electrode lead wires 36 extend from the catheter body 11
proximally through the axial bore 52 of the piston 46, the piston
chamber 41, the offset passageway 44 between the piston and
connector chambers 41 and 42, and into the connector chamber 42. A
teflon sheath 59 surrounds and protects the electrode lead wires 36
in the piston chamber 41, offset passageway 44 and connector
chamber 42. Within the piston chamber 41, or more preferably the
connector chamber 42, the lead wires 36 and sheath 59 are bowed or
looped to provide slack as the catheter is manipulated.
In the connector chamber 42, the lead wires 36 are connected to a
rotary connector 60. The rotary connector 60 comprises a
cylindrical male plug 61 extending proximally from the control
handle housing 40 coaxially with the housing 40. The plug 61 is of
conventional design and has a series of electrical contacts or
terminals 62 along its length, each of which is electrically
connected to a separate lead 62, and, therefore, a separate lead
wire 36, within the connector chamber 42. These terminals operate
independently to allow separate electrical signals to be
transmitted through the connector 60 simultaneously. The plug may
be inserted directly with a stimulator/recorder or other electrical
device or more preferably, connected to the female end to a
floating extension cable which in turn has a node plugged to its
opposite end which can be plugged into the electrical device.
In the embodiment shown, the catheter tip 12 carries four
electrodes and the rotary has four terminals. It is understood that
the number of electrodes and terminals may vary as required. Due to
its symmetry, the rotary connector 60 can continuously convey
electrical signals while the control handle 13 is rotated. This
allows greater freedom of movement of the catheter and particularly
the control handle without needing to reset the electrical
connections and risk losing data.
An annular flange 64 secures the rotary connector 60 to the housing
40 and seals the proximal end of the connector chamber 42.
Preferably, there is a vent 66 leading from the connector chamber
42. The vent 66 can be through the housing wall, flange 64 or
through the plug 61 of the rotary connector as shown.
The preceding description has presented with reference to a
presently preferred embodiment of the invention shown in the
drawings. Workers skilled in the art and technology to which this
invention pertains will appreciate that alterations and changes in
the described structures can be practiced without meaningfully
departing from the principal, spirit, and scope of this
invention.
For example, it is apparent that the invention is applicable to
catheters other than electrode catheters. In such other
embodiments, there may be no need for an electrical connector at
the proximal end of the control handle. Such other catheters may be
designed, for example, to deliver medications, or the like, to a
particular location in a body lumen or to take fluid samples from a
particular location. In such an embodiment, a continuous lumen may
extend through the housing, piston, catheter body, and catheter
tip. Other catheters to which this invention is applicable may
include, for example, an optic fiber for viewing the lumen or for
delivering laser irradiation to the lumen, e.g. to remove plaque in
a blood vessel.
It is also apparent that, if the catheter is an electrode catheter,
the number, size and location of the electrodes may vary. Moreover,
the rotary connector may, for convenience, include a cord extending
between the control handle housing and the male plug of the
connector. Such an embodiment is preferred if it is desired that
the handle not be adjacent the stimulator and/or recorder.
The design for the catheter may vary in other respects. For
example, the number of lumens in the catheter body and/or catheter
tip may vary as desired. It is preferred that the puller wire be
coaxial with the catheter body. To facilitate this, the electrode
lead wires may be wrapped around the puller wire sheath rather than
extending to one side as shown in the drawing.
While it is preferred that the handle be symmetrical about its
longitudinal axis to enable easy manipulation of the handle while
being rotated, it is understood that nonsymmetrical variations may
be used if desired. Likewise, it is understood that any suitable
method for attaching the puller wire to the catheter tip and to the
control handle housing may be used.
Accordingly, the foregoing description should not be read as
pertaining only to the precise structures described and shown in
the accompanying drawings, but rather should be read consistent
with and as support to the following claims which are to have their
fullest and fair scope.
* * * * *