U.S. patent application number 11/662128 was filed with the patent office on 2008-08-14 for minimally invasive surgical appartus and methods.
This patent application is currently assigned to ADVOTEK MEDICAL DEVICES LTD.. Invention is credited to Robert Julian Dickinson, Ajay Kumar Jain, Andrew Robert Pacey, Martin Terry Rothman.
Application Number | 20080194939 11/662128 |
Document ID | / |
Family ID | 33186680 |
Filed Date | 2008-08-14 |
United States Patent
Application |
20080194939 |
Kind Code |
A1 |
Dickinson; Robert Julian ;
et al. |
August 14, 2008 |
Minimally Invasive Surgical Appartus and Methods
Abstract
Apparutus and methods are described for performing percutancous
catheter-based interventional surgery. The apparatus comprises
first and second devices that are located in adjacent body
cavities, such as adjacent blood vessels, the first device being
capable of transmitting a directional signal that can be received
by the second device. The direction of the signal is correlated
with the facility to direct therapy, such that improved accuracy in
therapy placement is thereby achieved. Methods for treating
patients utilising the means and apparatus are also provided.
Inventors: |
Dickinson; Robert Julian;
(London, GB) ; Pacey; Andrew Robert; (Herts,
GB) ; Rothman; Martin Terry; (London, GB) ;
Jain; Ajay Kumar; (London, GB) |
Correspondence
Address: |
HOWARD & HOWARD ATTORNEYS, P.C.
THE PINEHURST OFFICE CENTER, SUITE #101, 39400 WOODWARD AVENUE
BLOOMFIELD HILLS
MI
48304-5151
US
|
Assignee: |
ADVOTEK MEDICAL DEVICES
LTD.
Stevenage
GB
|
Family ID: |
33186680 |
Appl. No.: |
11/662128 |
Filed: |
September 8, 2005 |
PCT Filed: |
September 8, 2005 |
PCT NO: |
PCT/GB05/03480 |
371 Date: |
January 3, 2008 |
Current U.S.
Class: |
600/407 ; 600/3;
604/164.12; 606/10; 606/170 |
Current CPC
Class: |
A61B 2017/1139 20130101;
A61B 2017/00252 20130101; A61B 2017/1107 20130101; A61B 2034/2051
20160201; A61B 17/2202 20130101; A61B 2090/3788 20160201; A61B
17/3478 20130101; A61B 34/20 20160201; A61F 2/966 20130101; A61B
2090/3929 20160201; A61B 17/11 20130101; A61B 2034/2063 20160201;
A61B 2090/3782 20160201; A61B 2090/3786 20160201; A61B 2017/22082
20130101 |
Class at
Publication: |
600/407 ;
604/164.12; 606/10; 600/3; 606/170 |
International
Class: |
A61B 17/00 20060101
A61B017/00 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 8, 2004 |
GB |
0419954.3 |
Claims
1-48. (canceled)
49. Apparatus for directing therapy within the body of a patient,
the apparatus comprising: a) a first therapeutic device that is
locatable within the lumen of a first body cavity, the first
therapeutic device comprising elongate body upon which is located a
signal transmitter for generating a directional signal; b) a second
therapeutic device that is locatable within the lumen of a second
body cavity adjacent to the first body cavity, the second
therapeutic device comprising an elongate body upon which is
located a receiver for receiving the directional signal; and c) a
therapeutic member for administering therapy to the body of the
patient wherein, therapy is directed by aligning the first
therapeutic device with the second therapeutic device via the
directional signal transmitted from the signal transmitter located
on first therapeutic device, which is received by the receiver
located on the second therapeutic device, and administering therapy
at a location that is aligned to the path taken by the directional
signal.
50. The apparatus of claim 49, wherein the therapeutic member is
comprised within the elongate body of the first therapeutic
device.
51. The apparatus of claim 49, wherein the therapeutic member is
comprised within the elongate body of the first therapeutic device
and can be retractably deployed therefrom.
52. The apparatus of claim 49, wherein the therapeutic member is
comprised within the elongate body of the second therapeutic
device.
53. The apparatus of claim 49, wherein the therapeutic member is
comprised within the elongate body of the second therapeutic device
and can be retractably deployed therefrom.
54. The apparatus of claim 49, wherein the directional signal is
selected from the group consisting of: ultrasound; laser radiation;
a radio signal; microwave radiation; and other electromagnetic
radiation.
55. The apparatus of claim 49, wherein the signal transmitter
comprises a signal transducer.
56. The apparatus of claim 49, wherein the signal transmitter
comprises an ultrasound signal transducer.
57. The apparatus of claim 49, wherein the signal transmitter
comprises an array of transducer elements.
58. The apparatus of claim 49, wherein the receiver comprises a
receiving transducer.
59. The apparatus of claim 49, wherein the receiver comprises an
ultrasound receiving transducer.
60. The apparatus of claim 49, wherein the receiver comprises a
receiving transducer that is an omnidirectional receiver.
61. The apparatus of claim 49, wherein the directional signal is
directed at an angle perpendicular to a longitudinal axis of the
elongate body of first therapeutic device.
62. The apparatus of claim 49, wherein the directional signal is
directed at an oblique angle relative a longitudinal axis of the
elongate body of the first therapeutic device.
63. The apparatus of claim 49, wherein the directional signal is
directed at an oblique angle relative a longitudinal axis of the
elongate body of the first therapeutic device and wherein the
oblique angle is preferably between around 20.degree. and around
60.degree. to the perpendicular, more preferably between around
30.degree. and around 50.degree. to the perpendicular, and most
preferably around 45.degree. to the perpendicular, when 0.degree.
corresponds to the longitudinal axis of the elongate body of the
first therapeutic device.
64. The apparatus of claim 49, wherein the first and second
therapeutic devices are catheters.
65. The apparatus of claim 49, wherein the therapeutic member
comprises a device selected from the group consisting of: a
cannula; a laser; a radiation-emitting device; a probe; a drill; a
blade; a wire; a needle; and combinations thereof.
66. The apparatus of claim 49, wherein the therapeutic member
further comprises one or more sensors.
67. The apparatus of claim 49, wherein the therapeutic member
further comprises a pressure sensor.
68. The apparatus of claim 49, wherein the therapeutic member
further comprises a signal transmitter.
69. The apparatus of claim 49, wherein the therapeutic member
further comprises a ultrasound transmitter.
70. The apparatus of claim 49, wherein the first and second body
cavities are blood vessels.
71. The apparatus of claim 49, wherein the first body cavity is an
artery and the second body cavity is a vein.
72. The apparatus of claim 49, wherein the first body cavity is a
vein and the second body cavity is an artery.
73. The apparatus of claim 49, wherein the elongate body of the
first therapeutic device further comprises at least one centering
member, for centering the first therapeutic device within the lumen
of the first body cavity, wherein the at least one centering member
comprises a device selected from the group consisting of: a
bladder; a balloon; a looped structure; a wire; a probe; a leg; a
coil; a helix; and an expandable stent.
74. The apparatus of claim 49, wherein the elongate body of the
second therapeutic device further comprises at least one centering
member, for centering the second therapeutic device within the
lumen of the second body cavity wherein the at least one centering
member comprises a device selected from the group consisting of: a
bladder; a balloon; a looped structure; a wire; a probe; a leg; a
coil; a helix; and an expandable stent.
75. The apparatus of claim 49, wherein the first therapeutic device
further comprises at least one centering member in the form of an
annular balloon which encircles the elongate body of the first
therapeutic device and that can be expanded radially outwardly
therfrom, thereby centering the first therapeutic device within the
lumen of the first body cavity.
76. The apparatus of claim 49, wherein the second therapeutic
device further comprises at least one centering member in the form
of an annular balloon which encircles the elongate body of the
second therapeutic device and that can be expanded radially
outwardly therfrom, thereby centering the second therapeutic device
within the lumen of the second body cavity.
77. The apparatus of claim 49, wherein the first therapeutic device
further comprises at least one centering member in the form of a
plurality of flexible members arranged in parallel at intervals
around the periphery of the elongate body of the first therapeutic
device, wherein compression of the plurality of flexible members
can be effected by way of a ring slidably located on the elongate
body at a position adjacent to the ends of the plurality of
flexible members, the sliding member being capable of translational
movement along the longitudinal axis of the elongate body, and
wherein the ring allows a compressive force to be applied to the
plurality of flexible members thereby causing the flexible members
bow outwardly relative to the elongate body of the first
therapeutic device.
78. The apparatus of claim 49, wherein the second therapeutic
device further comprises at least one centering member in the form
of a plurality of flexible members arranged in parallel at
intervals around the periphery of the elongate body of the second
therapeutic device, wherein compression of the plurality of
flexible members can be effected by way of a ring slidably located
on the elongate body at a position adjacent to the ends of the
plurality of flexible members, the sliding member being capable of
translational movement along the longitudinal axis of the elongate
body, and wherein the ring allows a compressive force to be applied
to the plurality of flexible members thereby causing the flexible
members bow outwardly relative to the elongate body of the second
therapeutic device.
79. A method for aligning a first therapeutic device, having an
elongate body, located within the lumen of a first body cavity with
a second therapeutic device, having an elongate body, located
within the lumen of a second body cavity that is adjacent to the
first body cavity, the method comprising: a) locating a signal
transmitter on the elongate body of the first therapeutic device,
wherein the signal transmitter is capable of generating a
directional signal; and b) locating a receiver on the elongate body
of the second therapeutic device, wherein the receiver is for
receiving the directional signal; wherein, alignment of the first
therapeutic device and the second therapeutic device in their
respective first and second body cavities is achieved when the
directional signal transmitted from the transmitter on the first
therapeutic device is received by the receiver on the second
therapeutic device.
80. The method of claim 79, wherein the directional signal is
selected from the group consisting of: ultrasound; laser radiation;
a radio signal; microwave radiation; and other electromagnetic
radiation.
81. The method of claim 79, wherein the signal transmitter
comprises a signal transducer.
82. The method of claim 79, wherein the signal transmitter
comprises an ultrasound transducer.
83. The method of claim 79, wherein the signal transmitter
comprises an array of signal transducer elements.
84. The method of claim 79, wherein the receiver comprises a
receiving transducer.
85. The method of claim 79, wherein the receiver comprises an
ultrasound receiving transducer.
86. The method of claim 79, wherein the receiver comprises an
omnidirectional receiving transducer.
87. The method of claim 79, wherein the directional signal is
directed at an angle perpendicular to a longitudinal axis of the
elongate body of the first therapeutic device.
88. The method of claim 79, wherein the directional signal is
directed at an oblique angle relative a longitudinal axis of the
elongate body of the first therapeutic device, and wherein the
oblique angle is preferably between around 20.degree. and around
60.degree. to the perpendicular, more preferably between around
30.degree. and around 50.degree. to the perpendicular, and most
preferably around 45.degree. to the perpendicular, when 0.degree.
corresponds to the longitudinal axis of the elongate body of the
first therapeutic device.
89. The method of claim 79, wherein the first and second
therapeutic devices are catheters.
90. Apparatus for traversing tissue intervening first and second
anatomical cavities within the body of an animal, comprising: a) a
launching device suitable for location within the first anatomical
cavity, the launching device comprising (i) an elongate outer
sheath with a distal end and a proximal end, the outer sheath
defining and enclosing an interior lumen; (ii) a signal transducer
located at the distal end of the outer sheath, the signal
transducer being arranged so as to transmit a directional signal;
and (iii) traversing member for traversing the tissue intervening
the first and second body cavities, the traversing member being
located within the lumen at the distal end of the outer sheath,
wherein in use the traversing member is in a retracted state and
can be extended out of the lumen via an aperture in the outer
sheath such that it engages and traverses the tissue intervening
the first and second anatomical cavities, and wherein extension of
the traversing means is along a path that is aligned with the
direction of the signal; and, b) a target device suitable for
location within the second anatomical cavity, the target device
comprising (i) an elongate outer sheath with a distal end and a
proximal end, the outer sheath defining and enclosing an interior
lumen; and (ii) a signal receiving transducer located at the distal
end of the outer sheath; (iii) wherein, in use, the signal
transducer on the launching device transmits the directional signal
that is capable of being received by the signal receiving
transducer on the target device, and when the signal is received by
the signal receiving transducer on target device it is determined
that the devices are located in the correct juxtaposition within
their respective anatomical cavities such that the traversing
member can be extended out of the launching device and traverses
the tissue intervening the first and second anatomical
cavities.
91. The apparatus of claim 90, wherein the directional signal is
selected from the group consisting of ultrasound, laser radiation,
a radio signal, microwave radiation and other electromagnetic
radiation.
92. The apparatus of claim 90, wherein the directional signal is
directed at an angle perpendicular to a longitudinal axis of the
launching device.
93. The apparatus of claim 90, wherein the directional signal is
directed at an oblique angle relative a longitudinal axis of the
launching device and wherein the oblique angle is preferably
between around 20.degree. and around 60.degree. to the
perpendicular, more preferably between around 30.degree. and around
50.degree. to the perpendicular, and most preferably around
45.degree. to the perpendicular, when 0.degree. corresponds to the
longitudinal axis of the launching device.
94. The apparatus of claim 90, wherein the traversing member
comprises a device selected from the group consisting of a cannula;
a laser; a radiation-emitting device; a probe; a drill; a blade; a
wire; a needle and combinations thereof.
95. The apparatus of claim 90, wherein the traversing member
traverses the tissue intervening the first and second anatomical
cavities along a path that is aligned to the path taken by the
directional signal.
96. The apparatus of claim 90, wherein the animal is a human.
97. A method for directing therapy in the body of a patient,
comprising: a) placing a first therapeutic device into a first body
cavity, the first therapeutic device comprising signal means for
generating a directional signal, and therapeutic means for
administering therapy to the body of the patient; and b) placing a
second therapeutic device into a second body cavity that is
adjacent to the first body cavity, the second therapeutic device
comprising receiving means for receiving the directional signal;
wherein, therapy is directed by aligning the first therapeutic
device with the second therapeutic device via the directional
signal transmitted by the first therapeutic device being received
by the second therapeutic device, and administering therapy at a
location that intersects the path taken by the directional
signal.
98. The method of claim 97, wherein the step of administering
therapy comprises creation of an aperture in tissue between the
first and second body cavities, thereby allowing fluid
communication between the first and second body cavities.
Description
FIELD OF THE INVENTION
[0001] The invention relates to apparatus and methods for
performing percutaneous catheter-based interventional surgery. In
particular, the invention relates to apparatus and techniques for
transvascular interstitial surgery.
BACKGROUND
[0002] Minimally invasive surgery, or `key-hole` surgery, allows
for surgical devices to be inserted into a patient's body cavity
through a small aperture cut. This form of surgery has become
increasingly popular as it allows patients treated successfully to
suffer less surgical discomfort while retaining the benefits of
conventional surgery. Patients treated by such techniques are
exposed to lower levels of trauma and their recovery times can be
significantly reduced compared to conventional surgical
procedures.
[0003] Key-hole surgery has been adopted as a favoured route for
performing laparoscopic surgery as well as in a number of
cardiovascular procedures. In the latter case, a balloon catheter
may be used to open a partially occluded coronary artery as an
alternative to open heart surgery. This technique is known as
balloon angioplasty. The balloon catheter is typically a small,
hollow, flexible tube that has a balloon near to its distal tip.
The catheter is inserted into an artery (usually near the patient's
groin) and then guided through the body to the patient's heart. The
heart and cardiac arteries are visualized by using X-ray
fluoroscopy, and blockages in the heart vessels are identified. A
balloon catheter is then inserted in or near the blockage and
inflated, thus widening the occluded blood vessel and helping to
restore blood flow to the cardiac tissue.
[0004] However, balloon angioplasty is not always a suitable
measure, especially in acute cases and in cases where a coronary
artery is completely occluded. In these instances the typical
treatment is to employ coronary bypass which involves open-heart
surgery. Hence, there is a need to provide new and improved methods
and apparatus for use in minimally invasive surgical procedures,
such the restoration of a blood supply to ischaemic tissue.
[0005] Conventional coronary bypass surgery is not always an option
for certain patients. Factors such as age, obesity, diabetes and
smoking can exclude a proportion of candidate patients who are in
genuine need of such treatment. In these cases it has been
postulated that minimally invasive surgery could provide a means
for treating a broader range of patients including those currently
excluded from standard techniques. Oesterle et al (Catheterization
and Cardiovascular Interventions (2003) 58: 212-218) describe a
technique they call percutaneous in situ coronary venous
arterialization (PICVA) which is a catheter based coronary bypass
procedure. In PICVA, the occlusion in the diseased artery is
`bypassed` by creation of a channel between the coronary artery and
the adjacent coronary vein. In this way the arterial blood is
diverted into the venous system and can perfuse the cardiac tissue
in a retrograde manner (retroperfusion). The technique of
retroperfusion has been known for some time, having first been
performed in humans by Beck in the 1940s and 1950s (for review see
Keelan et al. Current Interventional Cardiology Reports (2000) 2:
11-19). Apparatus and methods for performing procedures like PICVA
are described in WO-A-99/49793 and US-A-2004/0133225.
[0006] However, as the clinical results show in Oesterle et al.
(supra), successfully performing a minimally invasive procedure of
diverting blood flow from the coronary artery to the adjacent vein
has a low success rate. In six out of the 11 cases described this
was simply due to an inability to target the adjacent vein from the
artery. As such, Oesterle et al's procedure is too often doomed to
failure before it even starts. At present, the means for targeting
the catheter consist of a combination of X-ray fluoroscopy and an
imaging ultrasound probe located on the distal tip of the catheter
(e.g. see US-A-2004/0133225). Indeed, such an arrangement is
difficult to navigate and localisation of the adjacent vein
requires considerable skill on the part of the clinician. Hence,
there is a need for improvements in the means for targeting
devices, such as catheters, that are used for procedures such as
PICVA and in general transvascular surgery. Indeed, in the absence
of such improvement it seems that such techniques will remain
peripheral to the conventional surgical procedures of open-heart
coronary bypass.
SUMMARY OF THE INVENTION
[0007] The present invention provides means, methods and apparatus
for overcoming the problems identified in the prior art. Most
notably, the means, methods and apparatus of the invention allow
for greatly improved targeting and localisation of the therapy to
be administered. Hence, the invention shows particular advantage in
treating patients requiring coronary bypass by enabling minimally
invasive surgical techniques to be used more successfully than
previously known.
[0008] Accordingly, in a first aspect the invention provides a
means for directing therapy within the body of a patient, the means
comprising: [0009] a) a first therapeutic device that is located in
a first body cavity, the first therapeutic device comprising signal
means for generating a directional signal; [0010] b) a second
therapeutic device located in a second body cavity adjacent to the
first body cavity, the second therapeutic device comprising
receiving means for receiving the directional signal; and [0011] c)
therapeutic means for administering therapy to the body of the
patient wherein, therapy is directed by aligning the first
therapeutic device with the second therapeutic device via the
directional signal transmitted by the first therapeutic device
being received by the second therapeutic device, and administering
therapy at a location that is aligned to the path taken by the
directional signal.
[0012] Optionally the therapeutic means is comprised within either
the first or the second therapeutic devices. Typically, the first
and second medical devices are catheters. In embodiments of the
invention where the first therapeutic device comprises the
therapeutic means, the first device is also referred to herein as
the `launching device`. Likewise, where the second therapeutic
device does not comprise the therapeutic means it is, thus, also
referred to herein as the `target device`.
[0013] A second aspect of the invention provides means for aligning
a first therapeutic device located in a first body cavity with a
second therapeutic device located in a second body cavity adjacent
to the first body cavity, the means comprising: [0014] a) signal
means for generating a directional signal, the signal means being
located in the first therapeutic device; and [0015] b) receiving
means for receiving the directional signal, the receiving means
being located in the second therapeutic device;
[0016] wherein, alignment of the first therapeutic device and the
second therapeutic device is achieved when the directional signal
transmitted by the first therapeutic device is received by the
second therapeutic device.
[0017] A third aspect of the invention provides apparatus for
traversing tissue intervening first and second body cavities
comprising: [0018] a) a launching device suitable for location
within the first body cavity, the launching device comprising
[0019] (i) an elongate outer sheath with a distal end and a
proximal end, the outer sheath defining and enclosing an interior
lumen; [0020] (ii) a signal transducer located at the distal end of
the outer sheath, the signal transducer being arranged so as to
transmit a directional signal; and [0021] (iii) traversing means
for traversing the tissue intervening the first and second body
cavities, the traversing means being located within the lumen at
the distal end of the outer sheath, wherein in use the traversing
means is in a retracted state and can be extended out of the lumen
via an aperture in the outer sheath such that it engages and
traverses the tissue intervening the first and second body
cavities, and wherein extension of the traversing means is along a
path that is aligned with the direction of the signal; [0022] and,
[0023] b) a target device suitable for location within the second
body cavity, the target device comprising [0024] (i) an elongate
outer sheath with a distal end and a proximal end, the outer sheath
defining and enclosing an interior lumen; and [0025] (ii) a signal
receiving transducer located at the distal end of the outer
sheath;
[0026] wherein, in use, the signal transducer on the launching
device transmits the directional signal that is capable of being
received by the signal receiving transducer on the target device,
and
[0027] when the signal is received by the signal receiving
transducer on target device it is determined that the devices are
located in the correct juxtaposition within their respective body
cavities such that the traversing means can be extended out of the
launching device and traverses the tissue intervening the first and
second body cavities.
[0028] A fourth aspect of the invention provides a method for
directing therapy in the body of a patient, comprising: [0029] a)
placing a first therapeutic device into a first body cavity, the
first therapeutic device comprising signal means for generating a
directional signal, and therapeutic means for administering therapy
to the body of the patient; and [0030] b) placing a second
therapeutic device into a second body cavity that is adjacent to
the first body cavity, the second therapeutic device comprising
receiving means for receiving the directional signal;
[0031] wherein, therapy is directed by aligning the first
therapeutic device with the second therapeutic device via the
directional signal transmitted by the first therapeutic device
being received by the second therapeutic device, and administering
therapy at a location that is aligned to the path taken by the
directional signal.
[0032] In a particular embodiment of the invention the step of
administering therapy comprises creation of an aperture in tissue
between the first and second body cavities, thereby allowing fluid
communication between the first and second body cavities. In
accordance with the invention, the aperture is created at a
position that lies along the path taken by the directional
signal.
[0033] All references cited herein are incorporated by reference in
their entirety. Unless otherwise defined, all technical and
scientific terms used herein have the same meaning as commonly
understood by one of ordinary skill in the art to which this
invention belongs.
[0034] The invention is further illustrated by reference to the
accompanying drawings in which:
[0035] FIG. 1 is a representation of an embodiment of the invention
in which the launching device directs a signal from a first body
cavity to the target device located in an adjacent second body
cavity;
[0036] FIG. 2 is a cross sectional representation along the line of
BB in FIG. 1;
[0037] FIG. 3 is a representation of a specific embodiment of the
launching device of the invention;
[0038] FIG. 4 is a representation of a specific embodiment of the
target device of the invention. Arrow A shows the reversed
direction of blood flow after an arterial-venous stenosis (also
called PICVA) has been effected;
[0039] FIG. 5 is a representation of a specific embodiment of the
launching device of the invention in which the signal transducer is
comprised of an array of signal transducer elements;
[0040] FIG. 6 is a representation of an embodiment of the invention
wherein the launching and target devices comprise centring
means;
[0041] FIG. 7 is a representation of a stent in place following a
procedure such as arterial-venous stenosis. Interrupted arrow A
shows the direction of blood flow through the stent between the
first and second body cavities.
DETAILED DESCRIPTION OF THE INVENTION
[0042] In the embodiment of the invention as shown in FIG. 1, there
is provided a launching device (10), which comprises a signal
transmitter (12). The launching device (10) is typically a catheter
that consists of an elongate flexible rod-like portion and a tip
portion, and which provides a conduit for administering therapy
within the body of a patient. Hence, the launching device (10) is
suitable for location and movement through a first cavity or vessel
(30) within a patient's body. The elongate portion of the launching
device (10) comprises an outer sheath (11) that encloses a space,
defining a lumen (13). The space within the lumen (13) may be
suitably partitioned or subdivided as necessary so as to define
channels for administering therapy or controlling the positioning
of the launching device (10). Such subdivision may, for instance,
be achieved either longitudinally or concentrically in an axial
fashion.
[0043] A signal transducer (12) is located on the launching device
(10). The signal transducer (12) provides a signal (40) that is
directed outwards from the first launching device (10). In the
embodiment shown in FIG. 1 the signal (40) is directed radially
outward from the launching device (10) in a direction that is
perpendicular to the longitudinal axis of the launching device
(10). As mentioned in greater detail below, in alternative
embodiments of the invention the direction of the signal (40) need
not be perpendicular and can be directed at an angle to that of the
axis of the launching device (10). The signal transducer (12) is,
thus, comprised within the signal generating means of the apparatus
of the invention.
[0044] The signal transducer (12) is connected to signal
transmitter (50). The signal transmitted can be suitably selected
from ultrasound or appropriate electromagnetic sources such as a
laser, microwave radiation or via radio waves. In a specific
embodiment of the invention described in further detail below, the
signal transmitter (50) generates an ultrasound signal, which is
relayed to the signal transducer (12), which in turn directs the
signal (40) out of the body cavity (30) into the surrounding
tissue.
[0045] According to the invention, a second device is located
within an adjacent second body cavity or vessel (32). The first and
second body cavities (30 and 32 respectively) are separated by
intervening tissue (34), sometimes referred to as interstitial
tissue or a septum. The first and second body cavities (30, 32) are
located next to each other in a parallel fashion for at least a
portion of their respective lengths. For example, many of the veins
and arteries of the body are known to run in parallel with each
other for at least a portion of their overall length.
[0046] The second device is the target device (20), which assumes a
similar arrangement to that of the first device (10). The target
device (20) can also be a catheter that consists of an elongate
flexible rod-like portion and a tip portion, such that fine
movement and positioning of the target device (20) within the body
cavity (32) can be achieved. In common with the launching device
(10) the target device (20) comprises an outer sheath (21) that
encloses a space, defining a lumen (23). The lumen (23) can be
suitably partitioned as with the launching device (10).
[0047] The target device (20) comprises a receiving transducer (22)
for receiving the signal (40). The receiving transducer (22) is
comprised within the signal detection means of the apparatus of the
invention. In use, when the receiving transducer (22) receives the
signal (40) transmitted from signal transducer (12), it transmits
the received signal to signal detector (60). The signal detector
(60) provides an output reading to the user of the apparatus via
output display (61).
[0048] In this way, the transmission and detection of the directed
signal (40) allows for the navigation and positioning of the
launching device (10) relative to the target device (20). In use,
the launching device (10) and target device (20) can be maneuvered
by the user of the apparatus until the output display (61)
indicates that signal (40) is being received by the target device
(40).
[0049] In a specific embodiment of the invention, the signal (40)
is an ultrasound signal. The signal (40) is directional and is
emitted by the signal transducer (12) in shape of a narrow cone or
arc--i.e. with the width of the signal band increasing as the
distance from the signal transducer (12) increases. Hence, the
precision of alignment between the launching device (10) and the
target device (20) depends not only upon signal detection but also
upon the distance between the two devices, as at greater distances
the signal bandwidth is also greater. This level of error is
referred to as `positional uncertainty`. It will be appreciated
that a certain level of tolerance exists for positional
uncertainty, however, if therapy is to be directed with precision
the amount of uncertainty should be minimised. For example, if the
diameter (d) of the signal transducer (12) is 1 mm and the
frequency of the ultrasound signal is 30 MHz, then the positional
uncertainty (x)--i.e. the margin of error on either side of a
centre line--will be 1 mm at a perpendicular separation of 5 mm
between the launching and target devices (10, 20). For clinical
applications of the invention, it is preferred that the positional
uncertainty does not exceed around +/-5 mm (that is a total signal
bandwidth of 10 mm at the point reception). More preferably, the
positional uncertainty should be between around +/-0.01 mm and
around +/-4.50 mm. Even more preferably, the positional uncertainty
should be between around +/-0.1 mm and around .+-.2 mm. Ideally,
the positional uncertainty does not exceed around +/-1 mm.
[0050] The strength of the signal (40) will also be a determining
factor and it will be appreciated that signal strength will
diminish significantly as the distance between the launching device
(10) and the target device (20) increases. This distance is in part
determined by the amount of intervening tissue (34) between the two
devices. By way of example, if the signal (40) is an ultrasound
signal, it can be expected that significant deterioration of signal
will occur where the launching device (10) and the target device
(20) a separated by more than around 20 mm of solid tissue.
Obviously, the density of the intervening tissue (34) will also
have an effect upon the deterioration of signal (40) over
distance.
[0051] The frequency of the desired ultrasound signal also
determines the thickness of the signal transducer, which for a
standard ultrasound ceramic transducer--such as a PZT--will be
0.075 mm at 30 MHz.
[0052] FIG. 2 shows a cross sectional view of the arrangement in
FIG. 1, along the line BB. The correct orientation of the launching
device relative to the target device is an important factor as it
is this line of orientation (41) that determines where the therapy
is to be applied. It will be understood by the skilled addressee
that the clinical need for precisional placing of therapy in a
patient necessitates a requirement for a directional signal (40)
that is linked to the means for delivering therapy. In this way,
the user of the apparatus of the invention can administer therapy
to the correct location by ensuring that the launching device (10)
and the target device (20) are correctly positioned via
transmission and reception of the signal (40). Hence, the
orientation line (41) denotes not only the direction of signal
travel but also the path along which therapy can be administered to
the patient.
[0053] An embodiment of the invention is shown in FIG. 3 in which
the signal transducer (120) is oriented at an oblique angle
relative to the longitudinal axis of the launching device (10).
Hence, the signal (40) is transmitted at an angle that is in the
direction of forward travel of the launching device (10) as it
enters a body cavity (30). The preferred signal beam angle is
between around 20.degree. and around 60.degree. to the
perpendicular, more preferably between around 30.degree. and around
50.degree. to the perpendicular, and most preferably around
45.degree. to the perpendicular, when 0.degree. corresponds to the
longitudinal axis of the launching device in the direction of
travel.
[0054] The launching device (10) in FIG. 2, also shows an
embodiment of the invention in which one means for administering
therapy is provided. Launching device (10) comprises a hollow
needle or cannula (17). The hollow needle (17) is located in an
undeployed or retracted state within the lumen (13) of launching
device (10). The hollow needle (17) may be deployed/extended from
the launching device (10) at a time deemed appropriate by the user
of the apparatus, via an aperture (16) in the outer sheath (11),
The aperture (16), thus, can allow communication between the lumen
(13) and the body cavity (30). It should be noted that the hollow
needle (17) preferably travels along a path that is parallel to the
direction of the signal (40) and is used to pierce the intervening
tissue (34). In a preferred embodiment of the invention, the hollow
needle makes a transit across the entirety of the intervening
tissue (34) and in doing so allows the launching device (10) to
access the second body cavity (32). If desired, the pathway made by
the hollow needle (17) through the intervening tissue (34) can be
subsequently widened to allow fluid communication between the first
body cavity (30) and the second body cavity (32).
[0055] Therapeutic means suitable for use in the invention can
comprise devices or instruments selected from the group consisting
of a cannula; a laser; a radiation-emitting device; a probe; a
drill; a blade; a wire; a needle and appropriate combinations
thereof.
[0056] In a specific embodiment of the invention, the hollow needle
(17) comprises a sensor (19) so as to assist further in determining
positional information of the tip of the hollow needle relative to
the launching device. In another specific embodiment of the
invention the sensor (19) is capable of detecting changes in
hydrostatic pressure. Other sensors that are suitable for use in
the apparatus and methods of the invention can include temperature
sensors, oxygenation sensors and/or colour sensors
[0057] Optionally, the hollow needle can further comprise an
additional signal transducer (122). In the embodiment shown in FIG.
3 the signal transducer (122) is located near the tip of the hollow
needle on the end of a guide wire (14). However, the signal
transducer (122) can easily be located on the hollow needle if this
is preferred. In use, the signal transducer (122) is driven with a
short transmit pulse which produces a non-directional signal pulse.
The signal pulse can be detected by the receiving transducer (23)
mounted on the target device (20). From the time delay between the
transmit pulse to the receipt of the signal pulse on the receiving
transducer (23) the distance from the incoming guide wire (14) or
hollow needle (17) to the receiving transducer (23) and hence the
target device (20), can be determined.
[0058] As mentioned above, the target device (20) comprises a
receiving transducer (22) for receiving the signal (40). The
receiving transducer (22) can be unidirectional--i.e. capable of
receiving a signal from one direction only--or
omnidirectional--i.e. capable of receiving a signal from any
direction. In the embodiment of the invention shown in FIG. 4, a
target device (20) is located within a body cavity (32). The target
device (20) comprises an omnidirectional ultrasound signal
receiving transducer. A reflecting cone (601) directs the signal
(40) onto a disc-shaped receiving transducer (60). An acoustically
transparent window (602) separates the reflecting cone (601) from
the receiving transducer (60). In an alternative embodiment, an
omnidirectional ultrasound signal receiving transducer can be
obtained by locating cylinder of a flexible piezoelectric material
such as PVDF (polyvinyldifluoride) around the outer sheath of the
target device (20). In such a way the cylinder acts in an
equivalent manner to the receiving transducer (60).
[0059] FIG. 4 also shows an embodiment of the invention in which
the target device (20) comprises a channel (25) for administering
an agent, such as a therapeutic agent, to a patient. In a specific
embodiment, the channel (25) functions as a conduit to allow
application of a blocking material (251) that serves to obstruct or
occlude the body cavity (32). The blocking material (251) can be
suitably selected from a gel based substance. The placement of the
blocking material (251) can be directed by movement of the target
device (20). The presence of a guide member (24) within the lumen
(23) of the target device (20) allows the user of the apparatus to
precisely manipulate the position of the target device (20) as
required. Alternative blocking materials (251) can include
embolisation members (such as balloons) and self-expanding stents,
for example.
[0060] The launching device (10) comprises a signal transducer (12)
that is optionally oriented so that the signal (40) is transmitted
at an angle as shown in FIG. 2. In an alternative embodiment of the
invention, shown in FIG. 5, the signal transducer is in the form of
a signal transducer array (123). The signal transducer array (123)
comprises a plurality of signal transducer elements (124) which can
be oriented collectively and thereby define the signal beam width
and angle relative to the launching device (10). A further
advantage of the embodiment shown in FIG. 5, is that the smaller
size of the elements (124) means that the signal transducer does
not occupy a significant proportion the lumen (13) of the launching
device (10).
[0061] The embodiment in FIG. 5 is particularly suited to
ultrasound beam-forming signalling. FIG. 5 shows an array of signal
transducer elements (124) that are separately connected to the
transmitter (50) via delays (51) so that the signals to each
element are delayed relative to each other. The delays ensure that
the ultrasound wavefronts from each element are aligned to produce
a beam of ultrasound (40) at the requisite angle. In an alternative
embodiment where the signal (40) is in the form of visible light,
an array of LEDs can be used.
[0062] To assist in the process of alignment between the launching
device (10) in the first body cavity (30) and the target device
(20) in the second body cavity (32), a further embodiment of the
invention provides for the devices to comprise means for centring
the respective devices within the body cavities. In one embodiment
the centring means comprises an inflatable bladder or balloon (111)
which is located in the lumen (13, 23) when in an undeployed state
and, when the device (10, 20) reaches the desired location within
the patient, can be inflated. The balloon (111) can be annular in
shape such that is surrounds the device (10, 20) in a doughnut-like
fashion. The balloon (111) can also be arranged such that it
inflates on only one or on two opposite sides of the device. In
FIG. 6, an embodiment of the invention is shown where the balloon
(111) is shown deploying on one side of the launching device
(10).
[0063] Alternatively, in a further embodiment, the centring means
is comprised of one or more loop structures (211). In this
embodiment, the one or more loop structures (211) are located
either in the lumen (13, 23) or within recesses made in the outer
sheath (11, 21) when in an undeployed or retracted state. Hence,
when the device (10, 20) reaches the desired location within the
patient, the one or more loop structures (211) can be expanded
outwardly from the device (10, 20), thereby, centring the device
(10, 20) within the body cavity (30, 32). Outward expansion of the
loop structures (211) can be suitably effected by compression of a
length of wire, for example, such that it bows outwardly from the
outer sheath (11, 21). A centring device that adopts this
conformation typically comprises a plurality of compressible
lengths of wire, or other suitable flexible material, arranged in
parallel at radially spaced intervals around the periphery of the
outer sheath (11, 21). Compression of the plurality of wires can be
induced by way of a sliding member (not shown) located proximally
and/or distally near to the ends of the plurality of wires. The
sliding member is capable of translational movement along the
longitudinal axis of the device (10, 20).
[0064] In FIG. 6, an embodiment of the invention is shown where the
target device (20) comprises fully deployed centring means (211)
that has allowed the target device (20) to be centred within the
body cavity (32). Arrangements for centring the devices within the
body cavities include, but are not limited to, expandable
Chinese-lantern type devices, reversibly expandable stents, coils,
helices and retractable probes or legs.
[0065] The invention is further illustrated by the following
non-limiting example.
EXAMPLE
[0066] The methods and apparatus of the present invention
demonstrate particular utility in cardio-vascular surgery. In the
present example the apparatus of the invention is used by a
clinician to perform the procedure of arterial-venous stenosis
(PICVA) so as to enable retroperfusion of cardiac tissue following
occlusion of a coronary artery.
[0067] The launching catheter (10) is inserted into the occluded
coronary artery by standard keyhole surgical techniques. Likewise,
the target catheter (20) is inserted into the coronary vein that
runs parallel to the coronary artery. The coronary vein is not
occluded and, therefore, provides an alternative channel for blood
flow to the cardiac muscle effectively allowing the occlusion in
the coronary artery to be bypassed.
[0068] The launching catheter (10) comprises a PZT ultrasound
transducer (12) (CTS Piezoelectric Products, Albuquerque, N. Mex.)
that is oriented such that a directional ultrasound beam is
transmitted at a 45.degree. angle (relative to the longitudinal
axis of the launching device) in the direction of blood flow in the
artery. The ultrasound transducer (12) is activated and a 30 MHz
directional ultrasound signal (40) is transmitted from the
launching catheter (10). The target catheter (20) comprises an
omnidirectional ultrasound receiving transducer (60). To assist
with localisation of both the launching and target catheters (10,
20), both catheters comprise centring means in the form of an
annular inflatable balloon (111). The centring means on the
launching catheter (10) is deployed by the clinician when the
launching catheter (10) is deemed to be in an appropriate location
close to the site of the occlusion within the coronary artery. This
is typically determined via standard fluoroscopic imaging
techniques. The target catheter (20) is then moved within the
adjacent coronary vein until the directed ultrasound signal (40) is
detected by the signal receiving transducer (60). To enable more
precise alignment between the launching and target catheters (10,
20) the centring means (111) on the target catheter (20) can be
deployed either before or after the signal (40) is detected.
[0069] On reception of the transmitted signal (40) the clinician
can be certain that the launching and target catheters (10, 20) are
correctly located within their respective blood vessels to allow
for the arterial-venous stenosis procedure to commence. The target
catheter (20) is used to block blood flow within the coronary vein
via administration of a gel blocking material (251) though a
channel (25) in the target catheter (10). The blocking material
(251) is administered at a position downstream in terms of the
venous blood flow relative to the location of the receiving signal
transducer (60).
[0070] The clinician is then able to initiate arterial-venous
stenosis by deploying a hollow needle (17) from the launching
catheter (10) substantially along a path that is parallel and close
to that taken by the ultrasound signal (40) though the intervening
tissue (34) between the coronary artery and the coronary vein. The
hollow needle (17) comprises a sensor means (19) near its tip that
detects changes in hydrostatic pressure. Hence, the clinician is
able to monitor the transition from arterial pressure to venous
pressure as the hollow needle passes between the two vessels. The
hollow needle (17) further comprises a guide member (14) in the
form of a wire located in the bore of the needle. Once the hollow
needle has been passed across the intervening tissue (34) it is
retracted leaving the guide wire (14) in place. Alternatively, once
the hollow needle (17) has made the transition across the
intervening tissue (34) the clinician is able to pass the guide
wire (14) through the bore of the needle and then retract the
needle (17) into the launching catheter (10).
[0071] The clinician withdraws the launching catheter (10) from the
patient leaving the guide wire (14) in place. A further catheter
device is then slid along the guide wire (14) and an expandable
stent (26) is deployed in order to widen the perforation in the
intervening tissue (34) between the coronary artery and vein (see
FIG. 7). The target catheter (20) is withdrawn from the patient
leaving the blocking material (251) in position. Optionally, a
further block or suture may be inserted into the coronary vein
prevent reversal of arterial blood flow.
[0072] Hence, arterial blood is thereby diverted into the venous
system and is enabled to retroperfuse the cardiac muscle
tissue.
[0073] Whilst the specific example described above is restricted to
the field of cardio-vascular surgery, it is envisaged that the
present method and apparatus could have far reaching applications
in other forms of surgery. For example, any surgery involving the
need to direct therapy from one body cavity towards another
adjacent body cavity could be considered. Hence, the present
invention finds ready applications in the fields of neurosurgery,
urology and general vascular surgery. In addition the type of
therapy need not be restricted to formation of channels between
body cavities. For instance, the apparatus and methods described
herein are also of use in directing techniques such as catheter
ablation, non-contact mapping of heart chambers and the delivery of
medicaments to precise areas of the body.
[0074] Although particular embodiments of the invention have been
disclosed herein in detail, this has been done by way of example
and for the purposes of illustration only. The aforementioned
embodiments are not intended to be limiting with respect to the
scope of the appended claims, which follow. It is contemplated by
the inventors that various substitutions, alterations, and
modifications may be made to the invention without departing from
the spirit and scope of the invention as defined by the claims.
NUMERALS USED IN THE FIGURES
TABLE-US-00001 [0075] 10 Launching device 11 Outer sheath 111
Centring device 12 Signal transducer 120 Angled signal transducer
122 Needle mounted signal transducer 123 Signal transducer array
124 Signal transducer element 13 Lumen 14 Guide means 16 Aperture
17 Hollow needle 19 Pressure sensor 20 Target device 21 Outer
sheath 211 Centring device 22 Receiving transducer 23 Lumen 24
Guide member 25 Channel 251 Blocking material 26 Stent 30 First
body cavity 32 Second body cavity 34 Intervening tissue 40 Signal
41 Orientation direction 50 Signal transmitter 51 Transmitter delay
60 Signal detector 601 Reflecting cone 602 window 61 Output
display
* * * * *