 |
Claims  |
|
|
I claim:
1. A method for treating intravascular stenosis in a blood vessel utilizing
an intravascular expandable device comprising: an elongate tubular body
having a proximal end, a distal end and a central bore therethrough;
expandable pressure applying means including a flexible tubular member
extending from said distal end of said tubular body and a mechanical
mechanism within said flexible tubular member capable of engaging and
expanding said tubular member radially outwardly only; a tip member
connected to the distal end of said flexible tubular member; said
mechanism including a nut with an axis coaxial with the axis of said
tubular member, a plurality of curved-in-cross-section elongate baffles, a
plurality of linkages, each baffle being pivotally connected by one of
said linkages to said nut, said nut having threads therein, a threaded rod
extending axially through said bore and being journaled to said tubular
body or to said tip member, being received through said nut and being
capable of causing axial movement of said nut when rotated to cause each
linkage to move one of said baffles outwardly to expand said tubular
member, a bushing on said threaded rod adjacent the distal end thereof for
limiting axial movement of said nut on said threaded rod, each linkage
including an arm pivotally connected at one end to said nut and pivotally
connected at the other end to the underside of one of said baffles, and a
strut pivotally connected to said bushing and to one of said arms
intermediate the ends thereof, and expansion and retraction control means
coupled to said mechanical mechanism for causing said mechanism to expand
said flexible tubular member, to maintain said flexible tubular member
expanded and to allow said flexible tubular member to retract within a
stenotic area in a blood vessel, comprising the steps of: inserting the
expandable device into and through the lumen of a blood vessel;
positioning the expandable pressure applying means of the device within a
surrounding area of vascular stenosis; mechanically expanding the
expandable pressure applying means to cause same to bear against the
surrounding area of intravascular stenosis; providing passage means
bypassing the pressure applying means to allow blood to flow through or
around the pressure applying means while it is expanded; and maintaining
the mechanical pressure of the expanded pressure applying means against
the vessel wall for a predetermined time period of from one to five
minutes in order to dilate the stenoic stricture and restore the vessel to
its normal diameter.
2. The method of claim 1 further including the steps of: introducing
contrast material into the blood vessel; fluoroscopically monitoring the
contrast material through the area of stenosis to determine the extent of
stenotic reduction; and subsequently retracting and removing the
expandable pressure applying means from the vessel.
3. The method of claim 2 wherein the expandable pressure applying means are
removed when the flow of contrast material indicates uninterrupted blood
flow through the formerly stenotic area.
4. An intravascular expandable device adapted to be inserted within and
through the lumen of a blood vessel and manipulatable therethrough to a
stenotic area where it can be operated for re-establishing desired blood
flow through the blood vessel, said device comprising: an elongate tubular
body having a proximal end, a distal end and a central bore therethrough,
expandable pressure applying means including a flexible tubular member
extending from said distal end of said tubular body and a mechanical
mechanism within said flexible tubular member capable of engaging and
expanding said tubular member radially outwardly only; a tip member
connected to the distal end of said flexible tubular member; said
mechanism including a nut with an axis coaxial with the axis of said
tubular member, a plurality of curved-in-cross-section elongate baffles, a
plurality of linkages, each baffle being pivotally connected by one of
said linkages to said nut, said nut having threads therein, a threaded rod
extending axially through said bore and being journaled to said tubular
body or to said tip member, being received through said nut and being
capable of causing axial movement of said nut when rotated to cause each
linkage to move one of said baffles outwardly to expand said tubular
member, a bushing on said threaded rod adjacent the distal end thereof for
limiting axial movement of said nut on said threaded rod, each linkage
including an arm pivotally connected at one end to said nut and pivotally
connected at the other end to the underside of one of said baffles, and a
strut pivotally connected to said bushing and to one of said arms
intermediate the ends thereof, and expansion and retraction control means
coupled to said mechanical mechanism for causing said mechanism to expand
said flexible tubular member, to maintain said flexible tubular member
expanded and to allow said flexible tubular member to retract within a
stenotic area.
5. The device of claim 4 wherein said tip member, said expandable pressure
applying means and the distal end of said tubular body have passage means
for facilitating flow of blood through the device and back into the blood
vessel.
6. The device of claim 5 wherein said tip member and the distal end of said
tubular body are hollow and said passage means include at least one port
in the wall of said tip member and at least one port in the wall of said
tubular body at the distal end thereof to permit liquid flow through said
tip member, said flexible expandable tubular member and said tubular body
while a stenotic area is being dilated by said expandable pressure
applying means.
7. The device of claim 4 wherein said expansion and retraction control
means include a flexible rotatable shaft within said central bore of said
tubular body.
8. The device of claim 4 wherein said control means include a flexible
shaft within said tubular body coupled at its distal end to said threaded
rod and at its proximal end to a control knob.
9. The device of claim 8 wherein said flexible shaft has a knob mounted on
the proximal end thereof.
10. The device of claim 9 wherein the proximal end of said tubular body or
said knob has calibration markings and said knob or said proximal end of
said tubular body has an indicator relative to the calibration marking
indicating the extent of expansion of said flexible expandable tubular
member.
11. The device of claim 4 wherein said mechanism includes a hub mounted
within the hollow distal end of said tubular body, and the proximal end of
said threaded portion of said rod is journalled in said hub.
12. The device of claim 10 wherein said threaded rod is journalled at its
distal end to a bracket in said tip member.
13. The device of claim 4 wherein said tubular body has a diameter
approximately one-third the diameter of a blood vessel in which it is
received.
14. The device of claim 4 wherein said tubular body has a diameter between
approximately 1 mm and 3 mm.
15. The device of claim 14 wherein said tubular body has a diameter of
approximately 1.35 mm.
16. The device of claim 4 wherein said flexible expandable tubular member
is expandable from a diameter between 1 mm and 4.0 mm to a diameter
between 2.3 mm and 9.0 mm when expanded.
17. The device of claim 16 wherein said non-expanded diameter of said
flexible expandable tubular member is approximately 1.35 mm.
18. The device of claim 16 wherein said non-expanded diameter of said
flexible expandable tubular member is approximately 2.3 mm.
19. The device of claim 4 wherein said flexible expandable tubular member
is made of a biocompatible polymer.
20. The device of claim 19 wherein said polymer is polyurethane.
21. The device of claim 19 wherein said flexible expandable tubular member
has a wall thickness of approximately 0.002 mm.
22. The device of claim 7 wherein said tubular body is thick walled with a
lumen therethrough of sufficient cross section to receive said flexible
rotatable shaft therein. |
|
 |
|
 |
Claims |
|
|
|
Description |
|
|
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a pressure applying device and method for
using the device for treating intravascular stenosis within a blood vessel
in order to restore necessary blood flow therethrough. The device includes
an expandable intravascular pressure applying mechanism which is
positionable in an area of surrounding intravascular stenosis within a
blood vessel and operable to apply surface pressure against the inner wall
of the stenotic blood vessel in order to dilate the vessel and restore it
to a diameter closer to its normal diameter.
2. Description of the Prior Art
Heretofore various expandable devices have been proposed such as a
so-called balloon catheter having a balloon mounted to the distal end of
the catheter. The balloon is inserted into a vessel and inflated to a high
pressure with the infusion of liquid. As a result once a balloon has been
inflated in a vessel, flow of blood through the vessel is stopped.
Since vessels vary in thickness, a balloon catheter having a balloon of one
size may require multiple balloons for one procedure. Also, the balloon
itself may not be smooth when deflated and thus difficult to remove from
or insert into a blood vessel.
Another system for dilating an area of intravascular stenosis includes two
catheters, one slidably received over the other. In use, the smaller
catheter is inserted into the vessel. Then the longer catheter is slid
over the smaller catheter and, when it reaches the area of intravascular
stenosis, it forces the stenotic area outwardly thereby to dilate the
vessel in the area of intravascular stenosis.
Other such devices also have been proposed which have expanding splines or
ribs which extend outwardly from the surface of a catheter. Examples of
such previously proposed devices are disclosed in the following U.S.
Patents:
______________________________________
U.S. Pat. No. PATENTEE
______________________________________
2,649,092 Wallace
3,397,699 Kahl
3,568,659 Karnegis
4,228,802 Trott
4,362,150 Lombardi, Jr. et al
4,364,392 Strother et al
______________________________________
The Wallace U.S. Pat. No. 2,649,092 discloses a catheter which is adapted
to be employed in various urological procedures and which has
circumferentially spaced longitudinal slots adjacent the forward end
thereof. The portions of the catheter between the extremities of the slots
are flexible and outwardly distortable when the forward end of the
catheter is retracted with respect to the rearward end by means of a
flexible member anchored to the forward end to cause such portions to
exert pressure against the inner surface of a urethra in which the
catheter has been inserted.
The Kahl U.S. Pat. No. 3,397,699 discloses a bladder catheter having a
plurality of longitudinal slits distributed about a circumferential zone
adjacent to an aperture at a distal end of the catheter. The longitudinal
slits define therebetween a plurality of outwardly foldable wing elements
formed when the proximal and distal ends of the circumferential zone or
cylindrical envelope are drawn together by means of some resilient elastic
means, such as rubber elements, located on the interior wall of the
catheter and spanning the wing elements longitudinally. The catheter is
adapted to receive therein a stylet which is inserted through an open
proximal end of the catheter and is manipulated to draw the wing elements
inward for insertion and removal of the catheter. When the catheter is
positioned in a body cavity, particularly the bladder, the stylet is
withdrawn allowing the wing elements to fold outwardly, retaining the
expanded circumferential zone of the catheter in position.
The Karnegis U.S. Pat. No. 3,568,659 discloses an intercardiac heart pump
comprising a catheter having on its extremity an expandable and
contractable member. The catheter has a series of resilient, flexible ribs
spaced about the catheter and parallel to the catheter's axis. One end of
each rib is secured to the catheter adjacent the catheter tip, while the
other end of each rib is anchored to a ring connected to a reciprocating
member within the catheter which is slidably supported on the catheter.
The ribs are encircled by a resilient tube which is anchored to the
catheter beyond the ends of the ribs. When the reciprocating member is
moved forward in the catheter, the flexible ribs are caused to bow
outwardly, expanding the resilient tube which encircles the ribs. The
expandable part of the catheter can be positioned within the left
ventricle. When the ribs are flexed from a position generally parallel to
the catheter in an outwardly bowed position, the resilient tube can be
expanded to more or less fill the left ventricle.
The Trott U.S. Pat. No. 4,228,802 discloses a bladder catheter with a
mechanical expanding device near the distal end thereof which can be
operated by an actuator near the proximal external end thereof. The
catheter comprises a pair of tubes, one within the other, forming a pair
of interior lumina. The inner cylindrical lumen serves as a drainage
channel and the second outer lumen formed by the cross sectional space
between the two tubes provides a passage for irrigating fluids. Adjacent
the distal end of the outer tube are a plurality of traversely notched
splines on the inside of the outer tube extending longitudinally. parallel
to the axis of the catheter. The outer tube can be moved rearward relative
to the inner tube, thereby causing the splines to flex outwardly and
expanding the outer tube in the area of the splines.
The outer tube is moved by means of a threaded advancing nut assembly
including an annular flange formed on the proximal end of the outer tube,
a screw threaded portion along the length of the inner tube, and an
internally threaded nut which threadably engages the threaded portion on
the inner tube and frictionally engages the annular flange on the outer
tube. Rotation of the nut moves the outer tube rearwardly, flexing the
splines outwardly and expanding the outer tube.
In the expanded position, the catheter is retained in position in the
bladder. The inner tube also contains an auger-like spiral screw to
prevent blood clots and debris from blocking the drainage.
The Lombardi, Jr., et al. U.S. Pat. No. 4,362,150 discloses an intra-aortic
balloon pump attached to the end of a catheter. The proximal end of the
balloon is bonded to the distal end of the catheter while the distal end
of the balloon is bonded to the distal end of a rotatable tube within and
extending the length of the catheter. The rotatable tube is longitudinally
flexible and circumferentially rigid so that when a torque is applied to
the proximal end, the torque is transmitted the length of the tube to the
balloon. When the tube is rotated, the balloon is wrapped for insertion
into the aorta and unwrapped for pumping, then rewrapped for removal, the
balloon itself being pumped in a conventional manner via a lumen within
the catheter.
The Strother et al U.S. Pat. No. 4,364,392 discloses a method and apparatus
for providing therapeutic occlusions to blood vessels using an inflatable
balloon mounted at the end of a catheter.
As will be described in greater detail hereinafter, the device for treating
intravascular stenosis of the present invention differs from the devices
previously proposed by having therein a catheter with an expandable
pressure applying mechanism. The pressure applying mechanism is screw
activated and provides a number of advantages, such as providing a variety
of expansion sizes to accommodate varying sizes of blood vessels. An
expanding mechanism that cannot burst like a balloon, and a mechanism
which can be collapsed to conform closely to the diameter of the catheter
to minimize trauma upon insertion and withdrawal of the device into and
from a blood vessel.
Further, there is provided in the device passageways which allow the flow
of blood into, through and around the expandable pressure applying
mechanism for an extended period of time while the blood vessel is being
dilated by the device so that the flow of blood is not interrupted.
SUMMARY OF THE INVENTION
According to the invention there is provided a method for treating
intravascular stenosis in a blood vessel utilizing an intravascular
expandable device comprising: an elongate tubular body having a proximal
end, a distal end and a central bore therethrough; expandable pressure
applying means including a flexible tubular member extending from said
distal end of said tubular body and a mechanical mechanism within said
flexible tubular member capable of engaging and expanding said tubular
member radially outwardly only; a tip member connected to the distal end
of said flexible tubular member; said mechanism including a nut with an
axis coaxial with the axis of said tubular member, a plurality of
curved-in-cross-section elongate baffles, a plurality of linkages, each
baffle being pivotally connected by one of said linkages to said nut, said
nut having threads therein, a threaded rod extending axially through said
bore and being journaled to said tubular body or to said tip member, being
received through said nut and being capable of causing axial movement of
said nut when rotated to cause each linkage to move one of said baffles
outwardly to expand said tubular member, a rotatable bushing on said
threaded rod adjacent the distal end thereof for limiting axial movement
of said nut on said threaded rod, each linkage including an arm pivotally
connected at one end to said hub and pivotally connected at the other end
to the underside of one of said baffles, and a strut pivotally connected
to said bushing and to one of said arms intermediate the ends thereof, and
expansion and retraction control means coupled to said mechanical
mechanism for causing said mechanism to expand said flexible tubular
member, to maintain said flexible tubular member expanded and to allow
said flexible tubular member to retract within a stenotic area in a blood
vessel, comprising the steps of: inserting the expandable device into and
through the lumen of a blood vessel; positioning the expandable pressure
applying means of the device within a surrounding area of vascular
stenosis; mechanically expanding the expandable pressure applying means to
cause same to bear against the surrounding area of intravascular stenosis;
providing passage means bypassing the pressure applying means to allow
blood to flow through or around the pressure applying means while it is
expanded; and maintaining the mechanical pressure of the expanded pressure
applying means against the vessel wall for a predetermined time period of
from one to five minutes in order to dilate the stenoic stricture and
restore the vessel to its normal diameter.
Further according to the invention, there is provided an intravascular
expandable device adapted to be inserted within and through the lumen of a
blood vessel and manipulatable therethrough to a stenotic area where it
can be operated for re-establishing desired blood flow through the blood
vessel, said device comprising: an elongate tubular body having a proximal
end, a distal end and a central bore therethrough, expandable pressure
applying means including a flexible tubular member extending from said
distal end of said tubular body and a mechanical mechanism within said
flexible tubular member capable of engaging and expanding said tubular
member radially outwardly only; a tip member connected to the distal end
of said flexible tubular member; said mechanism including a nut with an
axis coaxial with the axis of said tubular member, a plurality of
curved-in-cross-section elongate baffles, a plurality of linkages, each
baffle being pivotally connected by one of said linkages to said nut, said
nut having threads therein, a threaded rod extending axially through said
bore and being journaled to said tubular body or to said tip member, being
received through said nut and being capable of causing axial movement of
said nut when rotated to cause each linkage to move one of said baffles
outwardly to expand said tubular member, a rotatable bushing on said
threaded rod adjacent the distal end thereof for limiting axial movement
of said nut on said threaded rod, each linkage including an arm pivotally
connected at one end to said hub and pivotally connected at the other end
to the underside of one of said baffles, and a strut pivotally connected
to said bushing and to one of said arms intermediate the ends thereof, and
expansion and retraction control means coupled to said mechanical
mechanism for causing said mechanism to expand said flexible tubular
member, to maintain said flexible tubular member expanded and to allow
said flexible tubular member to retract within a stenotic area.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a plan view of the intravascular expandable device of the present
invention and shows portions thereof broken away to a flexible shaft
extending through the tubular body of the device.
FIG. 2 is a vertical sectional view of the distal end of the intravascular
expandable device of FIG. 1 positioned in a blood vessel in an area of
surrounding intravascular stenosis and shows an expandable pressure
applying mechanism of the device retracted.
FIG. 3 is a vertical sectional view of the distal end of the intravascular
expandable device and shows the expandable pressure applying mechanism
expanded and bearing against the stenotic area of the blood vessel.
FIG. 4 is a cross sectional view of the intravascular expandable device
through the expandable pressure applying mechanism and is taken along line
4--4 of FIG. 2.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to FIG. 1, there is illustrated therein an intravascular
expansion device of the present invention generally identified by
reference numeral 10. According to the teachings of the present invention,
the device 10 is adapted to be inserted into and through the lumen of a
blood vessel and manipulatable therethrough to a position within an area
of intravascular stenosis. Then an expandable pressure applying mechanism
11 (FIG. 2) can be operated to dilate the stenotic vessel.
The device 10 also includes an elongate thick walled tubular body or
catheter 12, a hollow conical tip member 14, and an expandable, flexible
tubular member 16 which is mounted therebetween and which forms part of
the pressure applying mechanism 11. The tip member 14 and the tubular body
12 are made of a material that is relatively rigid relative to the
expandable flexible tubular member 16 and yet flexible enough to allow the
device 10 to be manipulated through a blood vessel.
The expandable pressure applying mechanism 11 (FIG. 2) is mounted within a
hollow distal end portion 17 of the tubular body 12 and within the
flexible tubular member 16 and includes four curved in cross-section,
elongate baffles 20 (FIG. 2) which define a generally cylindrical envelope
(FIG. 4). The baffles 20 extend approximately the length of the expandable
tubular member 16.
The expandable pressure applying mechanism 11 also includes and is
controlled by a flexible shaft or stylet 26 which extends through the
tubular body 12 through a bore 28 therein. A control knob 30 is connected
to the proximal end of the shaft 26. The knob 30 and shaft 26 define a
control mechanism for the pressure applying mechanism 11.
The tip member 14 has a plurality of, e.g., four, ports 32 and the tubular
body 12 has a plurality of, e.g., four, ports 34 in the hollow distal end
portion 17 which facilitate the flow of blood around or through the
pressure applying mechanism 11 and through the vessel when the pressure
applying mechanism 11 is expanded in the vessel. This construction permits
the pressure applying mechanism 11 to be expanded in a blood vessel
without interrupting the flow of blood so that a physician, or whoever is
operating the pressure applying mechanism 11, may maintain the pressure
applying mechanism 11 expanded in the blood vessel for an extended period
of time, if necessary, without interrupting the flow of blood.
Referring now to FIG. 2, the expandable pressure applying mechanism 11 of
the device 10 is shown positioned in an area of intravascular stenosis 35
in a blood vessel 36, with baffles 20 in a retracted position.
The pressure applying mechanism 11 includes a hub 38 having an annular base
40 circumferentially mounted to an inner wall 42 of the tubular body 12 in
the hollow distal end portion 17 thereof.
The hub 38 further includes a collar 44 and four legs 48 between the base
40 and collar 44. A threaded rod 50 is rotatably mounted or journalled
within the collar 44 and the distal end of the flexible shaft 26 is fixed
to the proximal end of the threaded rod 50 which is journalled in the
collar 44. At the proximal end of hollow distal end portion 17 a seal 52
is provided between shaft 26 and bore 28.
The expandable pressure applying mechanism 11 further includes a barrel or
nut 56 which is threadedly mounted on a rod 50. The threaded rod 50 has a
bushing 58 journalled on the distal end thereof for limiting axial
movement of the nut 56 thereon. If desired, the rod 50 can extend past or
beyond the bushing 58 and be journalled in a bracket, not shown, fixed
within tip member 14. Four arms 60 are pivotably connected to the nut 56
and pivotably connected to the underside of one of the baffles 20. Also
four restraining struts 62 are provided, each being pivoted at one end to
one of the arms 60 approximately midway between the ends thereof and at
the other end to rotatable bushing 58. Each arm 60 and strut 62 forms a
movable linkage 63.
The flexible tubular expandable member 16 is fixed to a shoulder 64 at the
proximal end of the conical tip member 14 and to a shoulder 65 at the
distal end of tubular body 12 with a continuous, smooth outer surface then
being provided on the periphery of the device 10 when the expandable
member 16 is collapsed. The expandable member 16 is made from a material
which is easily expandable beyond the diameter of the tip member 14 and
the tubular body 12. In this respect, the member 16 can be a tubular
section of approximately 0.002 mm thick silicone rubber, polyurethane or
other suitable biocompatible polymer.
In operating the device 10, the expandable mechanism 11 is first positioned
in a stenotic area 35. Then, the control know 30 is rotated to rotate
shaft 36 and threaded rod 50 thereby to advance the nut 56 to cause the
rods 60 to move outwardly and force the baffles 24 against the flexible
tubular member 16 to increase the diameter thereof. As the threaded nut 56
traverses the threaded rod 50, the arms 60 extend further outwardly and
finally to a position perpendicular to the threaded rod 50 to dilate a
stenotic stricture 66 in the stenotic area 35.
In order to obtain the desired dilation of the stenotic stricture 66 to
restore the vessel 36 to its normal inner diameter, various diameters of
the expandable member 16 can be utilized, depending upon the particular
vessel being treated and dependent upon what is shown by fluoroscopy or
other imaging technique employed. Also, the knob 30 will have calibration
markings or an indicator thereon relative to an indicator or calibration
markings on an adjacent block or sleeve 70 on the distal end of the
tubular body 12 to indicate to a user the amount of dilation for a
fractional rotation of the knob 30.
For example, a coronary vessel requires the device 10 to have an unexpanded
diameter of preferably no more than 1.35 mm and be expandable up to
approximately 4.00 mm in diameter. On the other hand, periphery vessels
require the device 10 to have an unexpanded diameter of preferably no more
than 2.3 mm and be expandable up to approximately 8 mm in diameter.
Typically, the tubular body or catheter 12 has a diameter approximately
one-third the diameter of the blood vessel into which it is inserted. Such
a diameter will typically be between 1 mm and 3 mm and one preferred
diameter is 1.35 mm. Another preferred diameter is 2.3 mm.
After a predetermined period of time, the expandable pressure applying
mechanism 11 is withdrawn from the stenotic area 35 and a contrast medium
can be introduced into the blood vessel 36 in order to determine whether
or not the stenotic stricture 66 has been reduced as a result of the
dilation of the blood vessel 36. The contrast medium is typically a
fluoroscopically detectable material which is radiographically monitored
by monitoring the flow of blood through the area 35 of stenosis. Once it
has been determined that the stenosis 35 has been reduced and blood flow
therethrough has returned to normal, the device 10 is removed from the
vessel 36.
Another technique for determining the extent of dilation of the stenotic
area in the blood vessel is by measuring the pressure on each side of the
formerly restricted intervascular stenotic area. This is accomplished with
a pressure sensing catheter device which is inserted in the vessel and
which is then utilized to measure pressure upstream and downstream of the
area where the intravascular stenosis was located. Small or no differences
in pressure then indicate effective dilation of the stenotic area.
Typically the holding time of the expandable mechanism 11 in a blood vessel
is 1 to 5 minutes.
From the foregoing description it will be apparent that the device 10 of
the present invention provides a number of advantages, some of which have
been described above and others of which are inherent in the invention. In
particular, the expandable pressure applying mechanism 11 will not burst
and can collapse to conform closely to the diameter of the device 10
rendering insertion and withdrawal less traumatic.
Further the expandable pressure applying mechanism 11 can accommodate
various diameter blood vessels because of the screw-activated adjustment
which may vary from 1.35 mm to 8.0 mm, depending upon the size of the
vessel being treated.
Still further, ports 32 and 34 provide means through which blood may flow
to permit the device 10 to be positioned in the stenotic area for an
extended period of time for maintaining the stenotic stricture 66 dilated
without interfering with the flow of blood therethrough.
Also it will be apparent to those skilled in the art that modifications can
be made to the device 10 of the present invention without departing from
the teachings of the invention.
Accordingly, the scope of the invention is only to be limited as
necessitated by the accompanying claims.
* * * * *
|
|
|
|
|
|
|
Description |
|
