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Description  |
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FIELD OF INVENTION
The Transluminal Lysing Device relates mainly to the group of art in
surgical instruments used for the removal of stenotic and occlusive
lesions from the vascular lumens of living mammals (thrombectomy,
atherectomy, endarterectomy).
BACKGROUND OF INVENTION
Due to the serious and debilitating nature of arteriosclerosis and its
prevalence among the United States population many devices have recently
been proposed and clinically tested that in some way relieve the
detrimental effects of stenotic and occlusive lesions in the vascular
system.
The "Transluminal Lysing Device" more specifically relates to surgical
instruments capable of excising and removing from the body the biological
material that makes up stenotic or occlusive lesions of biological lumens
and are also operable from a location outside of the lumen or location
outside of the body.
The following are prior art inventions having one or more similar
characteristics or physical appearance attributes, or a similar resultant
action to the invention described herein.
U.S. Pat. No. 4,030,503 Clark "Embolectomy Catheter" shows an open coil of
round or half round wire and a central core wire used for support, but
shows no method for enclosing material for removal from the body. Although
its appearance is similar to the Transluminal Lysing Device, it does not
perform the excision and removal process described by the invention
herein.
U.S. Pat. No. 3,683,891 Eskridge et al., "Tissue Auger" shows an open coil
of sharply disposed flat wire but shows no means for retaining tissue for
removal other than friction along the smooth inner walls of the retainment
chamber.
U.S. Pat. No. 4,653,496 Bundy et al., "Transluminal Lysing System" shows a
flexible variably spaced coil of specially shaped and sharpened wire and a
co-acting cutting cannula. Although some of the elements of the
Transluminal Lysing Device are similar to those elements found in the
"Transluminal Lysing System" the co-action of the elements work together
in a very different manner to cause a different resultant action (i.e. the
cutting mode) to achieve the same objectives of arterial patency and flow
improvement.
Several U.S. Patents, (i.e. Banko, Kerfoot, Royce, et al.) show devices
that remove tissue with an auger or auger and slot type arrangement. The
baffle plate in the distal end of the Transluminal Lysing Device might be
considered to operate in the fashion of an auger during engagement of the
lesion material The auger type devices as a whole are inflexible and might
not negotiate the tortuous blood vessels that need to be traversed to
excise atherosclerotic and other lesions. The cutting action of most of
these devices is that of a high speed rotary chipper or mill that creates
small particles for removal through the auger. The creation of a large
number of small particles in a blood vessel increases the chances for one
of these particles to escape into the distal flow to cause embolic
phenomenon, and is contrary to the objectives of this invention.
Technical and clinical information concerning a device called the Simpson
Shaver was disseminated at the Texas Heart Institute Annual Interventional
Cardiology Meeting in 1986 in Houston, Texas. The device has an inflexible
tip that acts as a receiver for a rotating bolt or blade that has a sharp
edge. Material is cut from the vessel wall and stored inside the end of
the receiver. This tool is more selective than the Transluminal Lysing
Device shown here. The selectivity is due to limitations of its
construction in that it cannot remove material located directly in front
of its distal end and is therefore incapable of removing total
obstructions. Also due to the small portion of the tool's total volume
that is used for material storage, several trips must be made to unload
the storage compartment.
Although the above mentioned prior art shows one or more similar attributes
in appearance or action to the Transluminal Lysing Device described
herein. No prior art shows the unique cutting action or operational
method, or material enclosure technique as shown in this invention.
The primary advantages of the present invention with respect to the prior
art are brought about by its unique construction and method of operation
The open coils of the Transluminal Lysing Device allow fast engagement
with little torsional resistance since all cutting does not take place
during rotation This also allows for deeper penetration. The lesion
material which is still firmly attached to the lumen wall during
engagement is more efficiently loaded relatively into the retainment
chamber for subsequent excision and removal than in the prior art. Since
the forces required for operating the tool are applied from outside the
lumen, a large amount of energy can be expended and larger cutting forces
applied during the excision process than is possible with similar prior
art. The method described herein allows the excision process to be divided
into discrete incremental parts engagement and excision. Energy for the
former applied by torsional forces in the transport structure and energy
for the latter applied by tensile and compressive forces in the core guide
wire and support structure respectively. Another useful advantage is the
high volumetric efficiency of this device. Through compression and
containment during excision, the tool can clear a volume of material
almost as large as its own closed volume. The device also clears a volume
proportional to its length in one operation or trip (an operation
involving the insertion and/or removal of a tool from a hole or shaft).
Other advantages of the invention will be apparent in the following
specifications.
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FIELD OF SEARCH
United States Classifications: 604/22, 46,47,49,52,53,164
264,266,267,274,281; 128/305,305F,310,751,753,754,755.
References:
______________________________________
2,850,007
"Biopsy Device" Lingley
3,082,805
"Tissue Macerator" Royce
3,683,891
"Tissue Auger" Eskridge
3,732,858
"Apparatus for removing Banko
blood clots . . . "
3,749,085
"Vascular Tissue Removing
Willson
Device"
3,945,375
"Rotatable Surgical Instrument"
Banko
3,976,077
"Eye Surgery Device" Kerfoot
4,030,503
"Embolectomy Catheter"
Clark
4,177,797
"Rotary Biopsy Device
Baylis
and Method . . . "
4,512,344
"Arthroscopic Surgery
Barber
Dissecting Apparatus"
4,653,496
"Transluminal Lysing System"
Bundy
______________________________________
OBJECTS OF THE INVENTION
The primary objective of this Invention is the removal of stenotic and
occlusive lesions from vascular lumina by the least invasive and least
traumatic means possible. Ideally this involves a peripheral percutaneous
transluminal approach to the site of the lesion, its excision and
subsequent improvement in blood flow parameters while the patient is
conscious.
It is a further object of this invention to introduce a new and unique
cutting method for use in the removal of stenotic and occlusive lesions.
It is a further object of this invention to entrap and enclose excised
lesion material for removal from the lumen, drastically reducing the
possibility of distal embolization of fragmented lesion material.
It is also an object of this invention to reduce morbidity and mortality in
procedures for the removal or circumvention of stenotic and occlusive
lesions and to reduce the need for traumatic alternative procedures such
as a vascular bypass grafting surgery.
It is a further object of this invention to reduce the cost of treatment of
vascular diseases that cause the formation of stenotic and occlusive
lesions in the vascular system.
Further objects and advantages of the new and unique concept described
herein will be more apparent after a study of the following drawings,
descriptions, and operational examples.
DETAILED DESCRIPTION OF DRAWINGS FIG. 1 is an enlarged 30 degree isometric
projection of the
Transluminal Lysing Device with an operational core
and guidance wire; FIG. 2 is an enlarged 30 degree oblique projection of
the
baffle plate, shown prior to installation and welding; FIG. 3 is an
enlarged cross section view of the Transluminal
Lysing Device revealing the core guidance wire, shown
just prior to engagement of a vascular lesion. FIG. 4 is an enlarged cross
section view of the Transluminal
Lysing Device revealing the core guidance wire, shown
just after rotational engagement of a vascular lesion. FIG. 5 is an
enlarged cross section view of the Transluminal
Lysing Device revealing the core guidance wire, shown
after excision and during removal of excised lesion
material from a vascular lumen;
DETAILED PHYSICAL DESCRIPTION OF THE DRAWINGS
Referring to FIG. 1 of the drawings The Transluminal Lysing Device cutting
helix 10 is formed by coiling specially shaped and sharpened wire around a
mandrel in the manner of a spring as shown in the prior art, however the
adjacent coils of the Transluminal Lysing Device are placed spacedly at an
axial pitch distance that approximates 2 or more times the width of the
wire over the working length 15 of the tool.
The non working length 11 being that part where the coil is bonded or other
wise connects with its support and transport structure 12 where axial
pitch has no particular importance.
The cylindrically shaped coil thus formed is the cutting helix 10 which has
a proximal and distal end. The proximal end is so disposed as to be bonded
on a support and transport means 12. The support and transport means 12 is
a generally cylindrical support but can be of any otherwise useful
configuration. The last distal coil or entrance tip 13 is sharpened at its
distal extremity so as to initially pierce and engage lesion material upon
rotation into a lesion or other material. Further rotation causes lesion
material to move relatively between the edges of adjacent coils and
between the vertical walls formed by the baffle plate 14.
The baffle plate 14 acts as a trap door and is located at the distal end of
the cutting helix providing an entry way for material into the central
space within the cutting helix 10, when the tool is rotated into lesion
material. When the working length 15 is contracted by use of the
core-guidance wire 16 or other means, the baffle plate 14 deforms into a
disk shaped obstruction blocking off the entry way for material at the
distal end of the cutting helix 10 and entrapping lesion material inside
the Transluminal Lysing Device. During this contraction, the sharp edges
at the outer diameter of the cutting helix coils along the working length
15 impinge upon the engaged tissue and sever this tissue from the lumen
wall, as the sharp edges of adjacent coils come into contact with each
other. FIG. 2 shows in more detail the preferred embodiment of the baffle
plate 14 showing a wire clearance passageway 19, a sharpened leading edge
20, and an attachment groove 21. The baffle plate 14 is attached to the
distal end or entrance tip 13 of the cutting helix 10 by electron beam
welding, lasing, brazing, chemical bonding, or other known means. During
lesion engagement, the baffle plate 14 acts in a manner analogous to an
earth boring auger or a single flight of a material transport auger.
Contraction of the working length 15 of the tool body to operate the
cutting and entrapping mechanism can be accomplished by means other than a
core guide wire. Temperature sensitive phase change or shape memory alloys
could be employed to form the cutting helix, and various means such as
lasing, electric resistance, or fluid circulation to alter the alloy's
temperature to cause contraction or expansion could be facilitated. These
emerging technologies are expensive and since one of the primary
objectives of the invention is the reduction of treatment costs the
preferred embodiment will show a core guidance wire used as a means for
effecting contraction and closure of the Transluminal Lysing Device.
The trap door function of the baffle plate 14 could be carried out by
various other means having other advantages such as multiple flights for
better sealing, special edge configurations to aid in the process of
bonding the plate to the coil or special guides to keep the core wire from
becoming entangled or otherwise interfering with the devices operation.
The core guidance wire 16 shown in FIG. 1 used to contract the cutting
helix length has what is known in the art as a floppy radiopaque tip 17 to
aid in guidance but has an added ability to engage itself by means of wire
stop 18 with the baffle plate 14 and is of sufficient tensile strength to
apply contact forces to the baffle plate necessary to effect closure of
the cutting helix body 10 along the working length 15 and deformation of
the baffle plate 14.
To ease operation of the device some sort of take up device or racheting
mechanism can be applied to the core wire with respect to the cutting
helix support structure so as to hold the cutting helix in its contracted
mode and prevent the accidental opening of the device once it has been
loaded.
OPERATIONAL DESCRIPTION
Methods for pre-treatment, access, and visualization as used in
intraluminal procedures of this nature are known in the art, but to
clarify, we reiterate that the procedure is carried out by operators
acting from a location outside of the afflicted lumen or outside of the
body containing the affected lumen.
After pre-treatment, access and visual localization, the core-guidance wire
16 is inserted into the lumen 22 shown in FIG. 3 and is then translated
flexibly to the site of the lesion 23 and across it. The cutting helix 10
is then inserted into the lumen and translated using an over the wire
technique to the site of lesion and in such a manner that the entrance tip
13 abutts the lesion material. Other useful delivery systems such as
sheaths or external guiding catheters such as known in the art could be
used to facilitate locating the device at the desired location.
Referring to FIG. 4, the cutting helix 10 is then rotated to engage and
lyse its way through the lesion 23. Due to the helical nature of the
cutting helix 10, rotation causes the tool to translate itself across the
lesion relative to the position of the lesion, or you may say it is self
advancing during rotational engagement.
Due to the uniform spacing between adjacent coils of the cutting helix 10,
no material is completely dislodged from the vessel wall during engagement
or rotationally induced translation. The material that is still attached
and supported by the lumen wall is well suited to pass between the opening
in the baffle plate 14 and progress toward the rear or proximal portion of
the cutting helix 10. When the distal end of the lesion 23 is reached by
the distal entrance tip 13, engagement is complete. It is noted here that
although the length of the tool is not a parameter of primary importance,
the length of the tool should be sufficient to totally engage over its
working length the lesion chosen for removal and not so long as to cause
tearing actions as might be encountered during contraction of an overly
long cutting helix 10.
Referring now to FIG. 5, the core wire 16 is then retracted sliding through
the center of the cutting helix 10 until the wire stop 18 contacts the
baffle plate 14. Further retraction of the core wire 16 then causes the
contraction of the cutting helix 10 and deformation of the baffle plate 14
so as to complete the excision of the remaining lesion material from the
lumen wall by the cutting helix 10 entrapping the excised material in an
area within the cutting helix and behind the baffle plate 14 and thereby
binding the volume of excised material within the cutting helix 10 along
the contracted working length 15. At this time, lesion material 24 has
been excised and stored within the tool and is ready for removal from the
lumen 22. It is important to note the simplicity and ease of operation
during removal of the lesion. This is important because of the fact that
during engagement of the lesion and prior to its removal; the lumen is
obstructed by the lesion, the device, the core wire, and transport
catheter. These obstructions restrict the flow of blood along the distal
path of the lumen. The shorter the time interval that blood flow is
restricted, the less likely ischemic complications to the patient will
occur. Visualization of the lumen after lesion removal will then
demonstrate whether patency or dynamic flow improvements have been
effected.
In Transluminal Lysing Devices of larger diameter the core-guidance wire
could take the form of a tube that would allow the in process measurement
of distal hemodynamic pressure in such a manner that the system's effects
on flow parameters could be monitored.
While the embodiment of the device herein described is especially suited
for operation in the vascular system, the inventive concepts and
constructions disclosed are capable of many other uses in biological
lumens or industrial lumens and should not be construed as a limiting set
of circumstances.
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