U.S. patent application number 10/779250 was filed with the patent office on 2004-08-19 for apparatus and method for an ultrasonic medical device to treat deep vein thrombosis.
This patent application is currently assigned to OmniSonics Medical Technologies, Inc.. Invention is credited to Hare, Bradley A., Rabiner, Robert A..
Application Number | 20040162571 10/779250 |
Document ID | / |
Family ID | 34435330 |
Filed Date | 2004-08-19 |
United States Patent
Application |
20040162571 |
Kind Code |
A1 |
Rabiner, Robert A. ; et
al. |
August 19, 2004 |
Apparatus and method for an ultrasonic medical device to treat deep
vein thrombosis
Abstract
An apparatus and method for an ultrasonic medical device to
treat deep vein thrombosis. The ultrasonic medical device comprises
an ultrasonic probe having a proximal end, a distal end and a
longitudinal axis therebetween. The ultrasonic probe is inserted
into a deep vein of a leg, navigated adjacent to a thrombus in the
deep vein and placed in communication with the thrombus. An
ultrasonic energy source is activated to generate a transverse
ultrasonic vibration along at least a portion of the longitudinal
axis of the ultrasonic probe. The transverse ultrasonic vibration
creates a plurality of transverse nodes and a plurality of
transverse anti-nodes along the longitudinal axis of the ultrasonic
probe, generating cavitation in a medium surrounding the ultrasonic
probe to ablate the thrombus and treat deep vein thrombosis.
Inventors: |
Rabiner, Robert A.; (North
Reading, MA) ; Hare, Bradley A.; (Chelmsford,
MA) |
Correspondence
Address: |
PALMER & DODGE, LLP
RICHARD B. SMITH
111 HUNTINGTON AVENUE
BOSTON
MA
02199
US
|
Assignee: |
OmniSonics Medical Technologies,
Inc.
|
Family ID: |
34435330 |
Appl. No.: |
10/779250 |
Filed: |
February 13, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10779250 |
Feb 13, 2004 |
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10665445 |
Sep 19, 2003 |
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10665445 |
Sep 19, 2003 |
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09776015 |
Feb 2, 2001 |
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6652547 |
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09776015 |
Feb 2, 2001 |
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09618352 |
Jul 19, 2000 |
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6551337 |
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60178901 |
Jan 28, 2000 |
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60157824 |
Oct 5, 1999 |
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Current U.S.
Class: |
606/159 ;
606/169 |
Current CPC
Class: |
A61N 7/022 20130101;
A61B 2217/007 20130101; A61B 2017/320084 20130101; A61B 2017/22008
20130101; A61B 2017/22051 20130101; A61B 2017/32007 20170801; A61B
2017/00778 20130101; A61B 2217/005 20130101; A61B 2018/00547
20130101; A61B 2018/00982 20130101; A61B 17/22012 20130101; A61B
2017/22081 20130101; A61M 1/85 20210501; A61B 2017/22018 20130101;
A61B 2017/00137 20130101; A61B 2017/22007 20130101; A61B 2017/00274
20130101; A61B 2017/22028 20130101; A61B 2017/22015 20130101; A61B
17/22004 20130101; A61B 2017/320089 20170801 |
Class at
Publication: |
606/159 ;
606/169 |
International
Class: |
A61B 017/22 |
Claims
What is claimed is:
1. An ultrasonic medical device for treating deep vein thrombosis
comprising: a flexible, ultrasonic probe having a proximal end, a
distal end and a longitudinal axis therebetween; a transducer
creating a transverse ultrasonic vibration along at least a portion
of the longitudinal axis of the flexible, ultrasonic probe; a
coupling engaging the proximal end of the flexible, ultrasonic
probe to a distal end of the transducer; an ultrasonic energy
source engaged to the transducer that produces an ultrasonic
energy, wherein the transverse ultrasonic vibration generates a
plurality of transverse nodes and a plurality of transverse
anti-nodes along at least a portion of the longitudinal axis of the
flexible, ultrasonic probe, creating cavitation in a medium
surrounding the flexible, ultrasonic probe to ablate a thrombus and
treat deep vein thrombosis.
2. The ultrasonic medical device of claim 1 wherein the flexible,
ultrasonic probe comprises a material that allows the flexible,
ultrasonic probe to be bent, deflected and flexed.
3. The ultrasonic medical device of claim 1 wherein the flexible,
ultrasonic probe comprises a diameter that enables insertion into a
vein.
4. The ultrasonic medical device of claim 1 wherein a diameter of
the flexible, ultrasonic probe has a uniform diameter from the
proximal end to the distal end.
5. The ultrasonic medical device of claim 1 wherein a diameter of
the flexible, ultrasonic probe varies from the proximal end to the
distal end.
6. The ultrasonic medical device of claim 1 wherein a cross section
of the flexible, ultrasonic probe is approximately circular.
7. The ultrasonic medical device of claim 1 wherein the transverse
ultrasonic vibration generates acoustic energy in a medium
surrounding the flexible, ultrasonic probe.
8. The ultrasonic medical device of claim 1 wherein the ultrasonic
energy source delivers ultrasonic energy in a frequencey range from
about 10 kHz to about 100 kHz.
9. The ultrasonic medical device of claim 1 wherein the ultrasonic
energy source provides an electrical energy to the transducer at a
resonant frequency of the transducer by finding the resonant
frequency of the transducer.
10. The ultrasonic medical device of claim 1 wherein the flexible,
ultrasonic probe is disposable.
11. An ultrasonic medical device for treating deep vein thrombosis
comprising: an ultrasonic probe having a proximal end, a distal end
terminating in a probe tip and a longitudinal axis between the
proximal end and the distal end; a transducer that converts
electrical energy into mechanical energy, creating a transverse
ultrasonic vibration along the longitudinal axis of the ultrasonic
probe; and a coupling engaging the proximal end of the ultrasonic
probe to a distal end of the transducer, wherein the transverse
ultrasonic vibration produces a plurality of transverse nodes and a
plurality of transverse anti-nodes along a portion of the
longitudinal axis of the ultrasonic probe.
12. The ultrasonic medical device of claim 11 wherein the
ultrasonic probe supports the transverse ultrasonic vibration when
flexed.
13. The ultrasonic medical device of claim 11 wherein the
ultrasonic probe has a flexibility allowing the ultrasonic probe to
be deflected and articulated.
14. The ultrasonic medical device of claim 11 wherein a transverse
wave from the transverse ultrasonic vibration is transmitted along
the longitudinal axis of the ultrasonic probe, creating an
interaction of a surface of the ultrasonic probe with a medium
surrounding the ultrasonic probe to create an acoustic wave in the
medium.
15. The ultrasonic medical device of claim 11 wherein the
transverse ultrasonic vibration of the ultrasonic probe produces
cavitation in a medium surrounding the ultrasonic probe to ablate a
thrombus to treat deep vein thrombosis.
16. The ultrasonic medical device of claim 11 wherein an ultrasonic
energy source is engaged to the transducer and provides the
electrical energy to the transducer.
17. A method of resolving deep vein thrombosis comprising:
providing an ultrasonic medical device comprising an ultrasonic
probe having a proximal end, a distal end and a longitudinal axis
therebetween; navigating the ultrasonic probe adjacent to a
thrombus; placing the ultrasonic probe in communication with the
thrombus; activating an ultrasonic energy source engaged to the
ultrasonic probe to generate a transverse ultrasonic vibration
along at least a portion of the longitudinal axis of the ultrasonic
probe, wherein the transverse ultrasonic vibration creates a
plurality of transverse nodes and a plurality of transverse
anti-nodes along a portion of the longitudinal axis of the
ultrasonic probe.
18. The method of claim 17 further comprising generating acoustic
energy in a medium surrounding the ultrasonic probe through the
transverse ultrasonic vibration of the ultrasonic probe.
19. The method of claim 17 further comprising sweeping the
ultrasonic probe along the thrombus.
20. The method of claim 17 further comprising moving the ultrasonic
probe back and forth along the thrombus.
21. The method of claim 17 further comprising rotating the
ultrasonic probe along the thrombus.
22. The method of claim 17 further comprising providing an
electrical energy to a transducer at a resonant frequency of the
transducer by the ultrasonic energy source determining the resonant
frequency of the transducer.
23. The method of claim 17 further comprising delivering ultrasonic
energy in a frequency range from about 10 kHz to about 100 kHz by
the ultrasonic energy source.
24. The method of claim 17 further comprising providing the
ultrasonic probe having a flexibility allowing the ultrasonic probe
to be deflected and articulated.
25. A method of ablating a thrombus in a deep vein of a body
comprising: providing an ultrasonic medical device comprising an
ultrasonic probe having a proximal end, a distal end terminating in
a probe tip, and a longitudinal axis between the proximal end and
the distal end; inserting the ultrasonic probe in an insertion
point of the deep vein; moving the ultrasonic probe to place the
ultrasonic probe in communication with the thrombus; activating an
ultrasonic energy source engaged to the ultrasonic probe to produce
an electric signal that drives a transducer of the ultrasonic
medical device to produce a transverse ultrasonic vibration of the
ultrasonic probe, wherein the transverse ultrasonic vibration
produces cavitation in a medium surrounding the ultrasonic probe to
ablate the thrombus.
26. The method of claim 25 further comprising transmitting a
transverse wave from the transverse ultrasonic vibration along the
longitudinal axis of the ultrasonic probe to create an acoustic
wave in the medium surrounding the ultrasonic probe.
27. The method of claim 25 further comprising producing a plurality
of transverse nodes and a plurality of transverse anti-nodes along
a portion of the longitudinal axis of the ultrasonic probe by the
transverse ultrasonic vibration.
28. The method of claim 27 wherein the plurality transverse nodes
are points of a minimum transverse ultrasonic vibration.
29. The method of claim 27 wherein the plurality of transverse
anti-nodes are points of a maximum transverse ultrasonic
vibration.
30. The method of claim 25 wherein the ultrasonic probe is for a
single use on a single patient.
31. The method of claim 25 further comprising delivering ultrasonic
energy in a frequency range of about 10 kHz to about 100 kHz by the
ultrasonic energy source.
Description
RELATED APPLICATIONS
[0001] This application is a continuation-in-part of application
Ser. No. 10/665,445, filed Sep. 19, 2003, which is a continuation
of application Ser. No. 09/776,015, filed Feb. 2, 2001, now U.S.
Pat. No. 6,652,547, which is a continuation-in-part of application
Ser. No. 09/618,352, filed Jul. 19, 2000, now U.S. Pat. No.
6,551,337, which claims benefit of Provisional Application Serial
No. 60/178,901, filed Jan. 28, 2000, and claims benefit of
Provisional Application Serial No. 60/157,824, filed Oct. 5, 1999,
the entirety of all these applications are hereby incorporated
herein by reference.
FIELD OF THE INVENTION
[0002] The present invention relates to medical devices, and more
importantly to an apparatus and a method for an ultrasonic medical
device to treat deep vein thrombosis.
BACKGROUND OF THE INVENTION
[0003] The formation of a blood clot or a thrombus in a deep vein
of a body, a condition known as deep vein thrombosis (DVT),
presents many problems to the individual suffering from the
condition. The blood clot or thrombus can lead to various
complications, including decreased blood flow and death. The
thrombus in the deep vein interferes with blood circulation in the
area of the thrombus and can break away and travel in the vein,
ultimately blocking a blood vessel in the lungs, brain, heart or
other critical areas of the body, a condition known as pulmonary
embolism (PE). DVT can also damage the valves in the vein by
inhibiting upward flow of blood, causing the blood to pool in the
leg. DVT most commonly occurs in the lower leg, upper leg and thigh
area.
[0004] DVT is a condition characterized by a reduction in blood
flow, with several factors increasing the susceptibility of
developing DVT. A person who has had a previous DVT condition is
more likely to have a subsequent DVT condition. Immobility, such as
prolonged sitting, long travel, surgical procedures or the
subsequent bed rest recovery from a surgical procedure, increases
the probability of developing DVT. The probability of a DVT
condition is increased by pregnancy, childbirth and the use of
medications such as estrogen and birth control pills. People
undergoing cancer treatments or having a history of polycythemia
vera, malignant tumors and inherited or acquired hypercoagulability
have a higher probability of developing DVT. The incidence of DVT
is more common in people over 40 years of age in addition to
individuals who are obese.
[0005] Many scientific studies have analyzed DVT. A study of
passengers who took a long haul flights over a six week period was
performed by New Zealand researchers. Subjects traveled for at
least ten hours per flight and each subject flew an average of
about thirty-nine hours over the study. The results of the study
showed that nine of the nearly nine hundred passengers developed a
blood clot. (Hughes et al., (Dec. 20, 2003) The Lancet, 362:
2039-2044). In a separate case, a twenty-eight year old female
British passenger on a twenty hour flight from Australia to London
died as a result of the DVT condition. A separate study in the
United Kingdom found that approximately one in two thousand people
develop DVT per year.
[0006] The prior art has discussed various ways of preventing and
treating DVT and pulmonary embolism. Prior art attempts to prevent
and treat DVT have used intermittent pressure on a leg of a patient
to help blood circulation. Through the application of intermittent
pressure to the leg, blood flow is directed through the leg and
into the torso.
[0007] U.S. Pat. No. 6,615,080 to Unsworth et al. discloses a
single channel neuromuscular electrical stimulation device for the
prevention of deep vein thrombosis, pulmonary embolism, lower
extremity edema and other associated conditions by electrical
stimulation of the muscles of the foot. Surface electrodes
positioned over the foot muscles are attached to a stimulator that
stimulates the foot muscles to reduce pooling of the blood in the
soleal veins of the calf. The Unsworth et al. disclosure is limited
to the soleal veins of the calf. The Unsworth et al. device does
not engage the area of the blood clot or thrombus, but rather
relies on electrical stimulation of the muscles to prevent DVT,
pulmonary embolism and lower extremity edema.
[0008] U.S. Pat. No. 6,290,662 to Morris et al. discloses an
apparatus for deep vein thrombosis prophylaxis and other conditions
comprising an inflatable/deflatable bladder disposed against an
extremity such as the upper calf, foot or hand of a patient. An
inelastic member of the Morris et al. device fully encloses the
bladder and body part while compressive forces are directed against
the body part when the bladder expands. The Morris et al. device
does not directly engage the area of the blood clot or thrombus,
but relies on the compressive forces to increase blood circulation
and translate to the problematic area of the blood clot or
thrombus. The Morris et al. device relies on a range of pressures
that may be too high or too low depending on the patient and may
not directly translate to increased blood flow.
[0009] The prior art does not provide a solution for preventing and
treating deep vein thrombosis in a safe, effective and time
efficient manner. The prior art does not provide a solution for
engaging the blood clot or the thrombus. Prior art instruments are
limited in that they rely upon electrical stimulation of the
muscles and transmission of the electrical simulation to the area
of the blood clot or thrombus. Prior art instruments use high
compressive forces to attempt to increase blood circulation.
Therefore, there remains a need in the art for an apparatus and a
method for an apparatus and a method of preventing and treating
deep vein thrombosis that engages the blood clot or thrombus while
not compromising the health of the patient.
SUMMARY OF THE INVENTION
[0010] The present invention provides an apparatus and a method for
an ultrasonic medical device to treat deep vein thrombosis. The
present invention is an ultrasonic medical device comprising a
flexible, ultrasonic probe having a proximal end, a distal end and
a longitudinal axis therebetween. The ultrasonic medical device
includes a transducer for creating a transverse ultrasonic
vibration along at least a portion of the longitudinal axis of the
flexible, ultrasonic probe. A coupling engages the proximal end of
the flexible, ultrasonic probe to a distal end of the transducer.
An ultrasonic energy source engaged to the transducer produces an
ultrasonic energy. The transverse ultrasonic vibration generates a
plurality of transverse nodes and a plurality of transverse
anti-nodes along at least a portion of the longitudinal axis of the
flexible, ultrasonic probe, creating cavitation in a medium
surrounding the flexible, ultrasonic probe to ablate a thrombus and
treat deep vein thrombosis.
[0011] The present invention is an ultrasonic medical device for
treating deep vein thrombosis comprising an ultrasonic probe having
a proximal end, a distal end terminating in a probe tip and a
longitudinal axis between the proximal end and the distal end. The
ultrasonic medical device includes a transducer that converts
electrical energy into mechanical energy, creating a transverse
ultrasonic vibration along the longitudinal axis of the ultrasonic
probe. A coupling engages the proximal end of the ultrasonic probe
to the distal end of the transducer. The transverse ultrasonic
vibration produces a plurality of transverse nodes and a plurality
of transverse anti-nodes along a portion of the longitudinal axis
of the ultrasonic probe.
[0012] The present invention is a method of resolving deep vein
thrombosis comprising: providing an ultrasonic medical device
comprising an ultrasonic probe having a proximal end, a distal end
and a longitudinal axis therebetween; navigating the ultrasonic
probe adjacent to a thrombus; placing the ultrasonic probe in
communication with the thrombus; and activating an ultrasonic
energy source engaged to the ultrasonic probe to generate a
transverse ultrasonic vibration along at least a portion of the
longitudinal axis of the ultrasonic probe, wherein the transverse
ultrasonic vibration creates a plurality of transverse nodes and a
plurality of transverse anti-nodes along a portion of the
longitudinal axis of the ultrasonic probe.
[0013] The present invention is a method of ablating a thrombus in
a deep vein of a body comprising providing an ultrasonic medical
device comprising an ultrasonic probe having a proximal end, a
distal end terminating in a probe tip and a longitudinal axis
between the proximal end and the distal end. The ultrasonic probe
is inserted into an insertion point in the deep vein and moved to
place the ultrasonic probe in communication with the thrombus. An
ultrasonic energy source engaged to the ultrasonic probe is
activated to produce an electric signal to drive a transducer of
the ultrasonic medical device to generate a transverse ultrasonic
vibration of the ultrasonic probe. The transverse ultrasonic
vibration produces cavitation in a medium surrounding the
ultrasonic probe to ablate the thrombus.
[0014] The present invention provides an apparatus and a method for
an ultrasonic medical device to treat deep vein thrombosis. An
ultrasonic probe is used to ablate a thrombus in a deep vein of the
leg, preventing the thrombus, or a portion of the thrombus, from
being carried with the blood to the heart and obstructing the flow
of blood to one or more arteries in the lungs. The present
invention provides an ultrasonic medical device that is simple,
user-friendly, time efficient, reliable and cost effective.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] The present invention will be further explained with
reference to the attached drawings, wherein like structures are
referred to by like numerals throughout the several views. The
drawings shown are not necessarily to scale, with emphasis instead
generally being placed upon illustrating the principles of the
present invention.
[0016] FIG. 1A is a side plan view of an ultrasonic probe of the
present invention inserted into a tibial deep vein of a leg where
the probe is moving toward a thrombus in the tibial vein.
[0017] FIG. 1B is a side plan view of an ultrasonic probe of the
present invention inserted into a popliteal deep vein of a leg
where the probe is moving toward a thrombus in the popliteal
vein.
[0018] FIG. 2 is a side plan view of an ultrasonic medical device
of the present invention capable of ablating a thrombus to treat
deep vein thrombosis.
[0019] FIG. 3 is a side plan view of an ultrasonic probe of the
present invention having an approximately uniform diameter from a
proximal end of the ultrasonic probe to the distal end of the
ultrasonic probe.
[0020] FIG. 4 is a view of a leg of a patient with deep veins,
superficial veins and short veins.
[0021] FIG. 5 is a view of a thrombus in a deep vein of a leg of a
patient.
[0022] FIG. 6 is a perspective view of an ultrasonic probe of the
present invention inserted in a deep vein of a leg and being moved
toward a thrombus in the deep vein.
[0023] FIG. 7 is an enlarged view of an ultrasonic probe of the
present invention in communication with a thrombus in a deep vein
of a body.
[0024] FIG. 8 is a view of an ultrasonic probe of the present
invention showing a plurality of transverse nodes and a plurality
of transverse anti-nodes while in communication with a thrombus in
a deep vein of a body.
[0025] While the above-identified drawings set forth preferred
embodiments of the present invention, other embodiments of the
present invention are also contemplated, as noted in the
discussion. This disclosure presents illustrative embodiments of
the present invention by way of representation and not limitation.
Numerous other modifications and embodiments can be devised by
those skilled in the art which fall within the scope and spirit of
the principles of the present invention.
DETAILED DESCRIPTION
[0026] The present invention provides an apparatus and a method for
using an ultrasonic medical device to ablate a thrombus to treat
deep vein thrombosis. The ultrasonic medical device comprises an
ultrasonic probe, a transducer, a coupling engaging a proximal end
of the ultrasonic probe to a distal end of the transducer and an
ultrasonic energy source engaged to the transducer. The ultrasonic
probe is inserted into a deep vein and placed in communication with
the thrombus. The ultrasonic energy source produces an ultrasonic
energy that is transmitted to the transducer, where the transducer
creates a transverse ultrasonic vibration along the ultrasonic
probe. The transverse ultrasonic vibration creates a plurality of
transverse nodes and a plurality of transverse anti-nodes along the
longitudinal axis of the ultrasonic probe, creating cavitation
along a portion of the longitudinal axis of the ultrasonic probe to
ablate the thrombus and treat deep vein thrombosis. By ablating the
thrombus in the deep vein, the thrombus or a portion of the
thrombus is not carried with the blood to the heart or the arteries
of the lungs where a pulmonary embolism can occur.
[0027] The following terms and definitions are used herein:
[0028] "Ablate" as used herein refers to removing, clearing,
destroying or taking away a thrombus. "Ablation" as used herein
refers to a removal, clearance, destruction, or taking away of the
thrombus.
[0029] "Anti-node" as used herein refers to a region of a maximum
energy emitted by an ultrasonic probe at or proximal to a specific
location along a longitudinal axis of the ultrasonic probe.
[0030] "Node" as used herein refers to a region of a minimum energy
emitted by an ultrasonic probe at or proximal to a specific
location along a longitudinal axis of the ultrasonic probe.
[0031] "Probe" as used herein refers to a device capable of
propagating an energy emitted by the ultrasonic energy source along
a longitudinal axis of the probe, resolving the energy into an
effective cavitational energy at a specific resonance (defined by a
plurality of nodes and a plurality of anti-nodes along an "active
area" of the probe) and is capable of an acoustic impedance
transformation of electrical energy to a mechanical energy.
[0032] "Thrombus" as used herein refers to a collection of a matter
including, but not limited to, a group of similar cells,
intravascular blood clots, occlusions, plaque, biological material,
fibrin, calcified plaque, calcium deposits, occlusional deposits,
atherosclerotic plaque, fatty deposits, adipose tissues,
atherosclerotic cholesterol buildup, fibrous material buildup,
arterial stenoses, minerals, high water content tissues, platelets,
cellular debris, wastes and other occlusive materials.
[0033] "Transverse" as used herein refers to a vibration of a probe
not parallel to a longitudinal axis of the probe. A "transverse
wave" as used herein is a wave propagated along the probe in which
a direction of a disturbance at a plurality of points of a medium
is not parallel to a wave vector.
[0034] An ultrasonic probe of an ultrasonic medical device of the
present invention capable of ablating a thrombus 80 to treat deep
vein thrombus is illustrated generally at 15 in FIG. 1A and FIG.
1B. FIG. 1A shows the ultrasonic probe 15 inserted at a lower calf
of a leg 74 into a deep vein 75 of the leg 74 and adjacent to the
thrombus 80 in the deep vein 75. In FIG. 1A, the ultrasonic probe
15 is inserted into a popliteal vein 72 in the lower calf area of
the leg 74. A flexibility of the ultrasonic probe allows the
ultrasonic probe 15 to be navigated within the deep vein 75.
[0035] FIG. 1B shows the ultrasonic probe 15 inserted at a calf
area into the deep vein 75 of the leg 74 and adjacent to the
thrombus 80 in the deep vein 75. In FIG. 1B, the ultrasonic probe
15 is inserted into the tibial vein 72.
[0036] FIG. 2 shows an ultrasonic medical device capable of
ablating a thrombus to treat deep vein thrombosis and prevent the
thrombus from obstructing a vasculature in the body. In a preferred
embodiment of the present invention, the ultrasonic probe 15 is
used to ablate a thrombus in a deep vein of a leg or a deep vein of
a pelvis. The ultrasonic medical device 11 includes an ultrasonic
probe 15 which is coupled to an ultrasonic energy source or
generator 99 for the production of an ultrasonic energy. A handle,
88, comprising a proximal end 87 and a distal end 86, surrounds a
transducer within the handle 88. The transducer, having a proximal
end engaging the ultrasonic energy source 99 and a distal end
coupled to a proximal end 31 of the ultrasonic probe 15, transmits
the ultrasonic energy to the ultrasonic probe 15. A connector 93
and a connecting wire 98 engage the ultrasonic energy source 99 to
the transducer. The ultrasonic probe 15 includes the proximal end
31, a distal end 24 that ends in a probe tip 9 and a longitudinal
axis between the proximal end 31 and the distal end 24. In a
preferred embodiment of the present invention shown in FIG. 2, a
diameter of the ultrasonic probe decreases from a first defined
interval 26 to a second defined interval 28 along the longitudinal
axis of the ultrasonic probe 15 over a transition 82. A coupling 33
that engages the proximal end 31 of the ultrasonic probe 15 to the
transducer within the handle 88 is illustrated generally in FIG. 2.
In a preferred embodiment of the present invention, the coupling is
a quick attachment-detachment system. An ultrasonic medical device
with a quick attachment-detachment system is described in the
Assignee's co-pending patent applications U.S. Ser. No. 09/975,725;
U.S. Ser. No. 10/268,487 and U.S. Ser. No. 10/268,843, and the
entirety of all these applications are hereby incorporated herein
by reference.
[0037] FIG. 3 shows an alternative embodiment of the ultrasonic
probe 15 of the present invention. In the embodiment of the present
invention shown in FIG. 3, the diameter of the ultrasonic probe 15
is approximately uniform from the proximal end 31 of the ultrasonic
probe 15 to the distal end 24 of the ultrasonic probe 15.
[0038] In a preferred embodiment of the present invention, the
ultrasonic probe 15 is a wire. In an embodiment of the present
invention, the ultrasonic probe 15 is elongated. In an embodiment
of the present invention, the diameter of the ultrasonic probe 15
changes at greater than two defined intervals. In an embodiment of
the present invention, the transitions 82 of the ultrasonic probe
15 are tapered to gradually change the diameter from the proximal
end 31 to the distal end 24 along the longitudinal axis of the
ultrasonic probe 15. In another embodiment of the present
invention, the transitions 82 of the ultrasonic probe 15 are
stepwise to change the diameter from the proximal end 31 to the
distal end 24 along the longitudinal axis of the ultrasonic probe
15. Those skilled in the art will recognize there can be any number
of defined intervals and transitions, and the transitions can be of
any shape known in the art and be within the spirit and scope of
the present invention.
[0039] In an embodiment of the present invention, the gradual
change of the diameter from the proximal end 31 to the distal end
24 occurs over the at least one transition 82, with each transition
82 having an approximately equal length. In another embodiment of
the present invention, the gradual change of the diameter from the
proximal end 31 to the distal end 24 occurs over a plurality of
transitions 82 with each transition 82 having a varying length. The
transition 82 refers to a section where the diameter varies from a
first diameter to a second diameter.
[0040] In a preferred embodiment of the present invention, the
ultrasonic probe 15 has a small diameter. In a preferred embodiment
of the present invention, the cross section of the ultrasonic probe
is approximately circular. In an embodiment of the present
invention, the diameter of the distal end 24 of the ultrasonic
probe 15 is about 0.004 inches. In another embodiment of the
present invention, the diameter of the distal end 24 of the
ultrasonic probe 15 is about 0.015 inches. In other embodiments of
the present invention, the diameter of the distal end 24 of the
ultrasonic probe 15 varies between about 0.003 inches and about
0.025 inches. Those skilled in the art will recognize an ultrasonic
probe 15 can have a diameter at the distal end 24 smaller than
about 0.003 inches, larger than about 0.025 inches, and between
about 0.003 inches and about 0.025 inches and be within the spirit
and scope of the present invention.
[0041] In an embodiment of the present invention, the diameter of
the proximal end 31 of the ultrasonic probe 15 is about 0.012
inches. In another embodiment of the present invention, the
diameter of the proximal end 31 of the ultrasonic probe 15 is about
0.025 inches. In other embodiments of the present invention, the
diameter of the proximal end 31 of the ultrasonic probe 15 varies
between about 0.003 inches and about 0.025 inches. Those skilled in
the art will recognize the ultrasonic probe 15 can have a diameter
at the proximal end 31 smaller than about 0.003 inches, larger than
about 0.025 inches, and between about 0.003 inches and about 0.025
inches and be within the spirit and scope of the present
invention.
[0042] The probe tip 9 can be any shape including, but not limited
to, rounded, bent, a ball or larger shapes. In a preferred
embodiment of the present invention, the probe tip 9 is smooth to
prevent damage to the deep veins 75 and the valves in the deep
veins 75. In one embodiment of the present invention, the
ultrasonic energy source 99 is a physical part of the ultrasonic
medical device 11. In another embodiment of the present invention,
the ultrasonic energy source 99 is not an integral part of the
ultrasonic medical device 11. The ultrasonic probe 15 is used to
ablate a thrombus and may be disposed of after use. In a preferred
embodiment of the present invention, the ultrasonic probe 15 is for
a single use and on a single patient., In a preferred embodiment of
the present invention, the ultrasonic probe 15 is disposable. In
another embodiment of the present invention, the ultrasonic probe
15 can be used multiple times.
[0043] The ultrasonic probe 15 is designed, constructed and
comprised of a material to not dampen the transverse ultrasonic
vibration, and thereby supports a transverse vibration when flexed.
In a preferred embodiment of the present invention, the ultrasonic
probe 15 comprises titanium or a titanium alloy. In a preferred
embodiment of the present invention, the ultrasonic probe 15
comprises titanium alloy Ti-6Al-4V. The elements comprising
Ti-6Al-4V and the representative elemental weight percentages of
Ti-6Al-4V are titanium (about 90%), aluminum (about 6%), vanadium
(about 4%), iron (maximum about 0.25%) and oxygen (maximum about
0.2%). Titanium is a strong, flexible, low density, low radiopacity
and easily fabricated metal that is used as a structural material.
Titanium and its alloys have excellent corrosion resistance in many
environments and have good elevated temperature properties. In
another embodiment of the present invention, the ultrasonic probe
15 comprises stainless steel. In another embodiment of the present
invention, the ultrasonic probe 15 comprises an alloy of stainless
steel. In another embodiment of the present invention, the
ultrasonic probe 15 comprises aluminum. In another embodiment of
the present invention, the ultrasonic probe 15 comprises an alloy
of aluminum. In another embodiment of the present invention, the
ultrasonic probe 15 comprises a combination of titanium and
stainless steel. Those skilled in the art will recognize that the
ultrasonic probe can be comprised of many other materials known in
the art and be within the spirit and scope of the present
invention.
[0044] The physical properties (i.e., length, cross sectional
shape, dimensions, etc.) and material properties (i.e., yield
strength, modulus, etc.) of the ultrasonic probe 15 are selected
for operation of the ultrasonic probe 15 in the transverse mode.
The length of the ultrasonic probe 15 of the present invention is
chosen to be resonant in a transverse mode. In an embodiment of the
present invention, the ultrasonic probe 15 is between about 30
centimeters and about 300 centimeters in length. Those skilled in
the art will recognize an ultrasonic probe can have a length
shorter than about 30 centimeters, a length longer than about 300
centimeters and a length between about 30 centimeters and about 300
centimeters and be within the spirit and scope of the present
invention.
[0045] The handle 88 surrounds the transducer located between the
proximal end 31 of the ultrasonic probe 15 and the connector 93. In
a preferred embodiment of the present invention, the transducer
includes, but is not limited to, a horn, an electrode, an
insulator, a backnut, a washer, a piezo microphone, and a piezo
drive. The transducer converts electrical energy provided by the
ultrasonic energy source 99 to mechanical energy and sets the
operating frequency of the ultrasonic medical device 11. The
transducer is capable of engaging the ultrasonic probe 15 at the
proximal end 31 with sufficient restraint to form an acoustical
mass that can propagate the ultrasonic energy provided by the
ultrasonic energy source 99.
[0046] FIG. 4 shows the main veins in the leg 74 including deep
veins 75, superficial veins 76 and short veins 77. The deep veins
75 of the leg 74 pass through the center of the leg 74 and are
surrounded by muscles. The superficial veins 76 of the leg 74 are
located in a fatty layer underneath the skin. The short veins 77 of
the leg 74, also known as connecting veins, link the deep veins 75
and the superficial veins 76.
[0047] The deep veins 75 of the leg 74 are important for the upward
flow of blood to the heart. The deep veins 75 comprise one way
valves that prevent the blood from flowing backward. The deep veins
75 lie deep within the muscle and carry most of the blood out of
the leg 74 and to the heart for oxygenation. Muscles surrounding
the deep veins 75, including the quadriceps, thigh muscles,
gastrocnemius, soleus, abductors, peroneus muscles, plantaris
muscles and popliteud muscles, compress the one way valves to help
force the blood in an upward direction toward the heart. The deep
veins 75 carry approximately ninety percent of the blood from the
legs 74 to the heart. Various deep veins 75 in the leg 74 include,
but are not limited to the common iliac, the femoral, the popliteal
71 and the tibial veins 72.
[0048] The deep veins generally follow the course of the associated
arteries. The tibial veins 72, also known as the peroneal veins,
are located in the calf. The anterior tibial veins 72 pass between
the tibia and the fibula along the leg 74. The anterior tibial
veins 72 receive blood from the knee joint, muscles of the thigh,
and upper calf and the join the posterior tibial vein 72 and the
popliteal vein 71. The popliteal vein 71 is formed by the junction
of the anterior and posterior tibial veins 72 and ascends to the
femoral vein. The popliteal vein 71 usually has four valves to
assist with the transportation of blood.
[0049] The superficial veins 76 of the leg 74 play a minor role in
carrying the blood to the heart. While the superficial veins 76
comprise one way valves that are similar to those in the deep veins
75, the one way valves in the superficial veins 76 are not
surrounded by muscle. The superficial veins 76 lie above the
muscles of the leg 74. Because the one way valves in the
superficial veins 76 are not surrounded by muscle, the flow of
blood upward in the superficial veins 76 is much slower when
compared to the blood flow in the deep veins 75. A majority of the
blood that flows up the superficial veins 76 is diverted into the
deep veins 75 through the short veins 77. Valves in the short veins
77 of the leg 74 allow the blood to flow from the superficial veins
76 to the deep veins 75, but not vice versa. Various superficial
veins 76 in the leg 74 include, but are not limited to, the great
saphenous and the lesser saphenous veins.
[0050] As discussed above, the deep veins 75, the superficial veins
76 and the short veins 77 all have valves that allow blood to flow
in one direction only, and prevent the blood from flowing back
towards the capillaries and collecting or puddling in the lower
leg. Disruption, inversion or damage to the valves can cause the
blood to flow down the veins in the wrong direction and puddle in
the lower leg. This disruption or damage to the valves causes the
veins to enlarge (varicose veins) or cause pain, leg swelling,
hypergigmentation and skin ulcers in the part of the leg 74 around
the ankle.
[0051] The valves in the veins are filamentous and composed of two
leaflets that allow blood to flow in only one direction to prevent
the blood from falling back into the leg after the leg muscles have
helped to propel the blood toward the heart. The ultrasonic probe
15 of the present invention is atraumatic and does not damage,
disrupt or invert the valves. The small diameter of the ultrasonic
probe 15 allows the ultrasonic probe 15 to be transited through an
opening in the valve without damaging the valve. The small diameter
of the ultrasonic probe 15 allows the ultrasonic probe 15 to
minimize contact with the valves as the ultrasonic probe 15 is fed
through the deep vein 75 and valves. The combination of the
flexibility of the ultrasonic probe 15 and the smooth probe tip 9
allows the ultrasonic probe 15 to be moved through the valve
without perforating the membrane comprising the valve while
maintaining the integrity of the valve. The flexibility of the
ultrasonic probe 15 allows the ultrasonic probe 15 to be deflected,
flexed and bent through the deep vein 75 and the valves. The smooth
probe tip 9 also prevents damage, disruption or inversion of the
valves upon retraction of the ultrasonic probe 15 from the deep
vein 75.
[0052] FIG. 5 shows a thrombus 80 in the deep vein 75 of the leg
74. The presence of the thrombus 80, or blood clot, in the deep
veins 75 of the leg presents a major risk to a patient. Since the
blood from the deep veins travels to the heart and ultimately to
the lungs, the thrombus 80 or at least a portion of the thrombus 80
in the deep veins 75 of the leg 74 can pass through the heart and
obstruct the flow of blood to one or more arteries in the lungs, a
condition known as pulmonary embolism. The degree of severity of
the pulmonary embolism depends on the size of the thrombus 80 and
the number of thrombi. A small thrombus 80 can block a small artery
in the lungs, causing a small piece of lung tissue to die, a
condition known as pulmonary infarction. A larger thrombus 80
presents a life threatening condition since the larger thrombus 80
can obstruct all or at least a majority of the blood travelling
from the right side of the heart to the lungs, thereby causing a
quick death. Therefore, removal of the thrombus 80 to treat deep
vein thrombosis is critical to the well being of the patient.
[0053] FIG. 6 shows the ultrasonic probe 15 inserted in the deep
vein 75 of the leg 74 being moved toward the thrombus 80. The
ultrasonic probe 15 has a stiffness that gives the ultrasonic probe
15 a flexibility allowing the ultrasonic probe 15 to be deflected,
flexed and bent through the tortuous paths of the vasculature,
including the deep vein 75. The ultrasonic probe 15 can be bent,
flexed and deflected to reach the thrombus 80 in the deep veins 75
of the leg 74 that would otherwise be difficult to reach.
[0054] FIG. 7 shows an enlarged view of a portion of the
longitudinal axis of the ultrasonic probe 15 in communication with
the thrombus 80 in the deep vein 75 of the leg 74. With the
ultrasonic probe 15 in communication with the thrombus 80, the
ultrasonic energy source 99 is activated to provide a low power
electric signal of between about 2 watts to about 6 watts to the
transducer that is located within the handle 88. The transducer
converts electrical energy provided by the ultrasonic energy source
99 to mechanical energy. The operating frequency of the ultrasonic
medical device 11 is set by the transducer and the ultrasonic
energy source 99 finds the resonant frequency of the transducer
through a Phase Lock Loop. By an appropriately oriented and driven
cylindrical array of piezoelectric crystals of the transducer, the
horn creates a longitudinal wave along at least a portion of the
longitudinal axis of the ultrasonic probe 15. The longitudinal wave
is converted to a transverse wave along at least a portion of the
longitudinal axis of the ultrasonic probe 15 through a nonlinear
dynamic buckling of the ultrasonic probe 15.
[0055] As the transverse wave is transmitted along the longitudinal
axis of the ultrasonic probe 15, a transverse ultrasonic vibration
is created along the longitudinal axis of the ultrasonic probe 15.
The ultrasonic probe 15 is vibrated in a transverse mode of
vibration. The transverse mode of vibration of the ultrasonic probe
15 differs from an axial (or longitudinal) mode of vibration
disclosed in the prior art. The transverse ultrasonic vibrations
along the longitudinal axis of the ultrasonic probe 15 create a
plurality of transverse nodes and a plurality of transverse
anti-nodes along a portion of the longitudinal axis of the
ultrasonic probe 15.
[0056] FIG. 8 shows the ultrasonic probe 15 of the present
invention having a plurality of transverse nodes 40 and a plurality
of transverse anti-nodes 42 along a portion of the longitudinal
axis of the ultrasonic probe 15 and in communication with the
thrombus 80. The transverse nodes 40 are areas of minimum energy
and minimum vibration. The transverse anti-nodes 42, or areas of
maximum energy and maximum vibration, also occur at repeating
intervals along the portion of the longitudinal axis of the
ultrasonic probe 15. The number of transverse nodes 40 and
transverse anti-nodes 42, and the spacing of the transverse nodes
40 and transverse anti-nodes 42 of the ultrasonic probe 15 depend
on the frequency of energy produced by the ultrasonic energy source
99. The separation of the transverse nodes 40 and transverse
anti-nodes 42 is a function of the frequency, and can be affected
by tuning the ultrasonic probe 15. In a properly tuned ultrasonic
probe 15, the transverse anti-nodes 42 will be found at a position
exactly one half of the distance between the transverse nodes 40
located adjacent to each side of the transverse anti-nodes 42.
[0057] The transverse wave is transmitted along the longitudinal
axis of the ultrasonic probe 15 and the interaction of the surface
of the ultrasonic probe 15 with the medium surrounding the
ultrasonic probe 15 creates an acoustic wave in the surrounding
medium. As the transverse wave is transmitted along the
longitudinal axis of the ultrasonic probe 15, the ultrasonic probe
15 vibrates transversely. The transverse motion of the ultrasonic
probe 15 produces cavitation in the medium surrounding the
ultrasonic probe 15 to ablate the thrombus 80. Cavitation is a
process in which small voids are formed in a surrounding medium
through the rapid motion of the ultrasonic probe 15 and the voids
are subsequently forced to compress. The compression of the voids
creates a wave of acoustic energy which acts to dissolve the matrix
binding the thrombus 80, while having no damaging effects on
healthy tissue. Action of the ultrasonic probe 15 results in
fibrinolysis and surface erosion of the thrombus 80.
[0058] The thrombus 80 in the deep vein 75 is resolved into a
particulate having a size on the order of red blood cells
(approximately 5 microns in diameter). The size of the particulate
is such that the particulate is easily discharged from the body
through conventional methods or simply dissolves into the blood
stream. A conventional method of discharging the particulate from
the body includes transferring the particulate through the blood
stream to the kidney where the particulate is excreted as bodily
waste. By resolving the thrombus 80 in the deep vein 75 to a
particulate, the particulate will travel with the blood to the
heart and ultimately to the arteries of the lungs without any risk
of obstructing the arteries and causing a pulmonary embolism or a
pulmonary infarction.
[0059] The transverse ultrasonic vibration of the ultrasonic probe
15 results in a portion of the longitudinal axis of the ultrasonic
probe 15 vibrated in a direction not parallel to the longitudinal
axis of the ultrasonic probe 15. The transverse vibration results
in movement of the longitudinal axis of the ultrasonic probe 15 in
a direction approximately perpendicular to the longitudinal axis of
the ultrasonic probe 15. Transversely vibrating ultrasonic probes
for biological material ablation are described in the Assignee's
U.S. Pat. No. 6,551,337; U.S. Pat. No. 6,652,547; and U.S. Pat. No.
6,660,013 and Assignee's co-pending patent application U.S. Ser.
No. 09/917,471, which further describe the design parameters for
such an ultrasonic probe and its use in ultrasonic devices for
ablation, and the entirety of these patents and patent applications
are hereby incorporated herein by reference.
[0060] As a consequence of the transverse ultrasonic vibration of
the ultrasonic probe 15, the thrombus destroying effects of the
ultrasonic medical device 11 are not limited to those regions of
the ultrasonic probe 15 that may come into contact with the
thrombus 80. Rather, as a section of the longitudinal axis of the
ultrasonic probe 15 is positioned in proximity to the thrombus 80,
the thrombus 80 is removed in all areas adjacent to the plurality
of energetic transverse nodes 40 and transverse anti-nodes 42 that
are produced along the portion of the length of the longitudinal
axis of the ultrasonic probe 15, typically in a region having a
radius of up to about 6 mm around the ultrasonic probe 15.
[0061] A novel feature of the present invention is the ability to
utilize ultrasonic probes 15 of extremely small diameter compared
to prior art probes, without loss of efficiency, because the
thrombus fragmentation process is not dependent on the area of the
probe tip 9. Highly flexible ultrasonic probes 15 can therefore be
designed to mimic device shapes that enable facile insertion into
thrombus areas or extremely narrow interstices that contain the
thrombus 80. Another advantage provided by the present invention is
the ability to rapidly move the thrombus 80 from large areas within
cylindrical or tubular surfaces.
[0062] The number of transverse nodes 40 and transverse anti-nodes
42 occurring along the longitudinal axis of the ultrasonic probe 15
is modulated by changing the frequency of energy supplied by the
ultrasonic energy source 99. The exact frequency, however, is not
critical and the ultrasonic energy source 99 run at, for example,
about 20 kHz is sufficient to create an effective number of
thrombus destroying transverse anti-nodes 42 along the longitudinal
axis of the ultrasonic probe 15. The low frequency requirement of
the present invention is a further advantage in that the low
frequency requirement leads to less damage to healthy tissue. Those
skilled in the art understand it is possible to adjust the
dimensions of the ultrasonic probe 15, including diameter, length
and distance to the ultrasonic energy source 99, in order to affect
the number and spacing of the transverse nodes 40 and transverse
anti-nodes 42 along a portion of the longitudinal axis of the
ultrasonic probe 15.
[0063] The present invention allows the use of ultrasonic energy to
be applied to the thrombus 80 selectively, because the ultrasonic
probe 15 conducts energy across a frequency range from about 10 kHz
through about 100 kHz. The amount of ultrasonic energy to be
applied to a particular treatment site is a function of the
amplitude and frequency of vibration of the ultrasonic probe 15. In
general, the amplitude or throw rate of the energy is in the range
of about 25 microns to about 250 microns, and the frequency in the
range of about 10 kHz to about 100 kHz. In a preferred embodiment
of the present invention, the frequency of ultrasonic energy is
from about 20 kHz to about 35 kHz.
[0064] The present invention also provides a method of preventing
deep vein thrombosis. A medical professional gains access to the
deep vein 75 in the leg 74 through an insertion point in the deep
vein 75. A device including, but not limited to, a vascular
introducer can be used to create an insertion point in the deep
vein 75 to gain access to the deep vein 75. A vascular introducer
for use with an ultrasonic probe is described in Assignee's
co-pending patent application U.S. Ser. No. 10/080,787, and the
entirety of this application is hereby incorporated herein by
reference.
[0065] After gaining access to the deep vein 75 in the leg 74, the
ultrasonic probe 15 is moved through the insertion point of the
deep vein 75, navigated through the deep vein 75 and placed
adjacent to the thrombus 80. In a preferred embodiment of the
present invention, the ultrasonic probe 15 is inserted in the deep
vein 75 below the thrombus 80 and navigated upward with the flow of
blood in the deep vein 75 toward the thrombus 80. Less force is
required in moving the ultrasonic probe 15 with the flow of blood
because there is less friction and viscous drag. In an alternative
embodiment of the present invention, the ultrasonic probe 15 is
inserted in the deep vein above the thrombus 80 and navigated
downward against the flow of blood in the deep vein 75 toward the
thrombus 80. While a greater force is required to navigate the
ultrasonic probe 15 against the flow of blood, the strength of the
ultrasonic probe 15 permits movement against the flow of blood.
Whether the ultrasonic probe 15 enters above or below the thrombus
80 is often dictated by anatomical considerations of the
patient.
[0066] The ultrasonic probe 15 is placed in communication with the
thrombus 80 by sweeping, twisting or rotating the ultrasonic probe
15 along the thrombus 80. Those skilled in the art will recognize
the ultrasonic probe can be placed in communication with the
thrombus in many ways known in the art and be within the spirit and
scope of the present invention.
[0067] The ultrasonic probe 15 is placed in communication with the
thrombus 80 and the ultrasonic energy source 99 engaged to the
ultrasonic probe 15 is activated to generate a transverse
ultrasonic vibration along at least a portion of the longitudinal
axis of the ultrasonic probe 15. The ultrasonic probe may then be
swept, twisted or rotated along the thrombus 80. The transverse
ultrasonic vibration creates a plurality of transverse nodes and a
plurality of transverse anti-nodes along a portion of the
longitudinal axis of the ultrasonic probe 15, causing a thrombus
destroying effect along the portion of the length of the
longitudinal axis of the ultrasonic probe 15.
[0068] The present invention also is a method of ablating the
thrombus 80 in the deep vein 75 of the body. Access to the deep
vein 75 in the leg 74 is gained by creating an insertion point in
the deep vein 75 using a device such as a vascular introducer. The
ultrasonic probe 15 having the proximal end 31, the distal end 24
terminating in the probe tip 9 and a longitudinal axis between the
proximal end and the distal end 24 is inserted through the
insertion point of the deep vein 75 and moved through the deep vein
75 and placed in communication with the thrombus 80. A stiffness of
the ultrasonic probe 15 of the ultrasonic medical device 11 gives
the ultrasonic probe 15 a flexibility allowing the ultrasonic probe
15 to be deflected, flexed and bent through the tortuous paths of
the vasculature, including the deep vein 75. The ultrasonic energy
source 99 engaged to the ultrasonic probe 15 is activated to
produce an electric signal to drive the transducer of the
ultrasonic medical device 11 to produce a transverse vibration of
the ultrasonic probe 15. The transverse ultrasonic vibration of the
ultrasonic probe 15 produces cavitation in a medium surrounding a
portion of the length of the longitudinal axis of the ultrasonic
probe 15 to ablate the thrombus 80.
[0069] A method of resolving deep vein thrombosis comprising
providing an ultrasonic medical device 11 comprising an ultrasonic
probe 15 having a proximal end 31, a distal end 24 and a
longitudinal axis therebetween; navigating the ultrasonic probe 15
proximal to a thrombus 80; placing the ultrasonic probe 15 in
communication with the thrombus 80; activating an ultrasonic energy
source 99 engaged to the ultrasonic probe 15 to generate a
transverse ultrasonic vibration along at least a portion of the
longitudinal axis of the ultrasonic probe 15, wherein the
transverse vibration creates a plurality of transverse nodes 40 and
a plurality of transverse anti-nodes 42 along a portion of the
longitudinal axis of the ultrasonic probe 15.
[0070] A method of ablating a thrombus 80 in a deep vein 75 of a
body comprising providing an ultrasonic medical device 11
comprising an ultrasonic probe 15 having a proximal end 31, a
distal end 24 terminating in a probe tip 9, and a longitudinal axis
between the proximal end 31 and the distal end 24; inserting the
ultrasonic probe 15 in an insertion point of the deep vein 75;
moving the ultrasonic probe 15 to place the ultrasonic probe 15 in
communication with the thrombus 80; activating an ultrasonic energy
source 99 engaged to the ultrasonic probe 15 to produce an electric
signal that drives a transducer of the ultrasonic medical device 11
to produce a transverse ultrasonic vibration of the ultrasonic
probe 15, wherein the transverse ultrasonic vibration produces
cavitation in a medium surrounding the ultrasonic probe 15 to
ablate the thrombus 80.
[0071] In an alternative embodiment of the present invention, the
ultrasonic probe 15 is vibrated in a torsional mode. In the
torsional mode of vibration, a portion of the longitudinal axis of
the ultrasonic probe 15 comprises a radially asymmetric cross
section and the length of the ultrasonic probe 15 is chosen to be
resonant in the torsional mode. In the torsional mode of vibration,
a transducer transmits ultrasonic energy received from the
ultrasonic energy source 99 to the ultrasonic probe 15, causing the
ultrasonic probe 15 to vibrate torsionally. The ultrasonic energy
source 99 produces the electrical energy that is used to produce a
torsional vibration along the longitudinal axis of the ultrasonic
probe 15. The torsional vibration is a torsional oscillation
whereby equally spaced points along the longitudinal axis of the
ultrasonic probe 15 including the probe tip 9 vibrate back and
forth in a short arc about the longitudinal axis of the ultrasonic
probe 15. A section proximal to each of a plurality of torsional
nodes and a section distal to each of the plurality of torsional
nodes are vibrated out of phase, with the proximal section vibrated
in a clockwise direction and the distal section vibrated in a
counterclockwise direction, or vice versa. The torsional vibration
results in an ultrasonic energy transfer to the biological material
with minimal loss of ultrasonic energy that could limit the
effectiveness of the ultrasonic medical device 11. The torsional
vibration produces a rotation and a counterrotation along the
longitudinal axis of the ultrasonic probe 15 that creates the
plurality of torsional nodes and a plurality of torsional
anti-nodes along a portion of the longitudinal axis of the
ultrasonic probe 15 resulting in cavitation along the portion of
the longitudinal axis of the ultrasonic probe 15 comprising the
radially asymmetric cross section in a medium surrounding the
ultrasonic probe 15 that ablates the biological material. An
apparatus and method for an ultrasonic medical device operating in
a torsional mode is described in Assignee's co-pending patent
application U.S. Ser. No. 00/000,000 (Attorney Docket No.
20563/2422), filed Feb. 9, 2004, and the entirety of this
application is hereby incorporated herein by reference.
[0072] In another embodiment of the present invention, the
ultrasonic probe 15 is vibrated in a torsional mode and a
transverse mode. A transducer transmits ultrasonic energy from the
ultrasonic energy source 99 to the ultrasonic probe 15, creating a
torsional vibration of the ultrasonic probe 15. The torsional
vibration induces a transverse vibration along an active area of
the ultrasonic probe 15, creating a plurality of nodes and a
plurality of anti-nodes along the active area that result in
cavitation in a medium surrounding the ultrasonic probe 15. The
active area of the ultrasonic probe 15 undergoes both the torsional
vibration and the transverse vibration.
[0073] Depending upon physical properties (i.e., length, diameter,
etc.) and material properties (i.e., yield strength, modulus, etc.)
of the ultrasonic probe 15, the transverse vibration is excited by
the torsional vibration. Coupling of the torsional mode of
vibration and the transverse mode of vibration is possible because
of common shear components for the elastic forces. The transverse
vibration is induced when the frequency of the transducer is close
to a transverse resonant frequency of the ultrasonic probe 15. The
combination of the torsional mode of vibration and the transverse
mode of vibration is possible because for each torsional mode of
vibration, there are many close transverse modes of vibration. By
applying tension on the ultrasonic probe 15, for example by bending
the ultrasonic probe 15, the transverse vibration is tuned into
coincidence with the torsional vibration. The bending causes a
shift in frequency due to changes in tension. In the torsional mode
of vibration and the transverse mode of vibration, the active area
of the ultrasonic probe 15 is vibrated in a direction not parallel
to the longitudinal axis of the ultrasonic probe 15 while equally
spaced points along the longitudinal axis of the ultrasonic probe
15 in a proximal section vibrate back and forth in a short arc
about the longitudinal axis of the ultrasonic probe 15. An
apparatus and method for an ultrasonic medical device operating in
a transverse mode and a torsional mode is described in Assignee's
co-pending patent application U.S. Ser. No. 00/000,000 (Attorney
Docket No. 20563/2432), filed Feb. 9, 2004, and the entirety of
this application is hereby incorporated herein by reference.
[0074] While the above discussion and figures focus on the venous
removal of the thrombus 80, the present invention can also be used
for the arterial removal of the thrombus 80. The ultrasonic probe
15 of the present invention can not only be used in the deep veins
of the leg for venous removal of thrombus 80, but the ultrasonic
probe 15 can also be adapted for use in the arteries of the leg for
arterial removal of thrombus 80.
[0075] The present invention provides and apparatus and a method
for an ultrasonic medical device to treat deep vein thrombosis. An
ultrasonic probe is used to ablate a thrombus in a deep vein of the
leg, preventing the thrombus, or a portion of the thrombus, from
being carried with the blood to the heart and obstructing the flow
of blood to one or more arteries in the lungs. The present
invention provides an ultrasonic medical device to treat deep vein
thrombosis that is simple, user-friendly, time efficient, reliable
and cost effective.
[0076] All patents, patent applications, and published references
cited herein are hereby incorporated herein by reference in their
entirety. While this invention has been particularly shown and
described with references to preferred embodiments thereof, it will
be understood by those skilled in the art that various changes in
form and details may be made therein without departing from the
scope of the invention encompassed by the appended claims.
* * * * *