U.S. patent application number 11/055858 was filed with the patent office on 2005-06-30 for applicator for microwave radiation treatment.
This patent application is currently assigned to Imperial College Innovations Limited. Invention is credited to Habib, Nagy Adly, Sangster, Alan John.
Application Number | 20050143795 11/055858 |
Document ID | / |
Family ID | 10836774 |
Filed Date | 2005-06-30 |
United States Patent
Application |
20050143795 |
Kind Code |
A1 |
Habib, Nagy Adly ; et
al. |
June 30, 2005 |
Applicator for microwave radiation treatment
Abstract
A device for restricting the loss of blood during a surgical
procedure is disclosed. The device generates localized heating in
an organ or volume of tissue and includes an applicator that is
positioned against an organ or tissue to be treated, an array of
retractable needles that deliver irradiating energy in the vicinity
of a selected incision point; a switching mechanism in
communication with the needles for energizing and causing movement
of the needles and a power unit for supplying irradiating power to
the needles when extended into the organ or tissue.
Inventors: |
Habib, Nagy Adly; (London,
GB) ; Sangster, Alan John; (Edinburgh, GB) |
Correspondence
Address: |
OPPENHEIMER WOLFF & DONNELLY LLP
45 SOUTH SEVENTH STREET, SUITE 3300
MINNEAPOLIS
MN
55402
US
|
Assignee: |
Imperial College Innovations
Limited
London
GB
|
Family ID: |
10836774 |
Appl. No.: |
11/055858 |
Filed: |
February 11, 2005 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
11055858 |
Feb 11, 2005 |
|
|
|
10625232 |
Jul 22, 2003 |
|
|
|
10625232 |
Jul 22, 2003 |
|
|
|
09762285 |
Apr 6, 2001 |
|
|
|
6628990 |
|
|
|
|
09762285 |
Apr 6, 2001 |
|
|
|
PCT/GB99/02559 |
Aug 4, 1999 |
|
|
|
Current U.S.
Class: |
607/101 |
Current CPC
Class: |
A61B 18/1815 20130101;
A61N 5/04 20130101; A61B 18/18 20130101; A61N 5/045 20130101 |
Class at
Publication: |
607/101 |
International
Class: |
A61F 002/00 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 5, 1998 |
GB |
9817078.0 |
Claims
1. A device for restricting the loss of blood during a surgical
procedure comprising: (i) an applicator having a face for
positioning against an organ or tissue to be treated; (ii) an array
of retractable needles extending from said face capable of
irradiating said organ or tissue to be treated in a vicinity of a
selected incision point; (iii) a switching mechanism in
communication with said array of retractable needles for energizing
and releasing said array of retractable needles; (iv) and a power
unit in communication with said array of retractable needles for
supplying irradiating power to said needles when extended into said
organ or tissue in the vicinity of the selected incision point.
2. The device of claim 1 wherein the power unit supplies sufficient
power for a period required to raise the temperature of said organ
or tissue in the vicinity of the selected incision point by about
20.degree. C. to about 30.degree. C.
3. The device of claim 1 wherein said array of retractable needles
provide local heating of the organ or tissue within a volume
approximately 5 cm long, 2 cm wide and 4 cm deep.
4. The device of claim 1 wherein the applicator includes a collar
to which the array of retractable needles are secured.
5. The device of claim 4 wherein movement of the needles is
effected by a solenoid mechanism acting on the collar.
6. The device of claim 5 wherein the solenoid mechanism includes a
spring for effecting movement of said needles.
7. The device of claim 1 wherein the power is microwave power.
8. The device of claim 1 wherein the needle array comprises about
twenty needles.
Description
RELATED APPLICATIONS
[0001] This application is a divisional of U.S. patent application
Ser. No. 10/625,232, filed Jul. 22, 2003, which is a continuation
of U.S. patent application Ser. No. 09/762,285, filed Apr. 6, 2001,
now U.S. Pat. No. 6,628,990, which is a national stage application
of International Patent Application No. PCT/GB99/02559, filed Aug.
4, 1999, which claims priority from GB Patent Application No.
9817078.0, filed Aug. 5, 1998.
FIELD OF THE INVENTION
[0002] This invention relates to a device for use in the surgical
treatment of human or non-human animals. In particular, it is
concerned with a device for use in controlling excessive bleeding
from severed tissue during surgical procedures, especially on the
patient's liver.
BACKGROUND OF THE INVENTION
[0003] It is well known that raising the temperature of body tissue
tends to reduce blood flow within the tissue. If the temperature is
raised by 20-30.degree. C. above normal, blood flow within the
tissue is greatly diminished.
[0004] In surgical procedures performed on deep-seated body tissues
and organs, e.g. the liver, blood loss from severed tissue can be a
serious problem. There is an obvious need for a device which can
assist in limiting such blood loss and, as indicated above, this
can be achieved by means of the application of heat. Widespread
heating can be achieved relatively easily, but this is not
desirable. Very localised heating is required in order to minimise
damage to surrounding tissues. In liver surgery, local heating of
the liver is ideally required in a tissue volume approximately 5 cm
long by 2 cm wide by 4 cm deep; this volume is centred on the
planned point of incision. Furthermore, it is important for the
local elevation of temperature to be achieved quickly just prior to
commencing the surgical procedure.
SUMMARY OF THE INVENTION
[0005] The present invention aims to provide a device for providing
localised heating of a selected region of body tissue prior to
surgical incision of that tissue.
[0006] According to one aspect of the present invention, there is
provided a device for generating localised heating in a selected
body tissue, which device comprises an applicator including a
source of microwave radiation and an array of retractable needles
arranged so as to extend from one face of the applicator and, in
operation, to confine the irradiated microwave energy field
emanating from the applicator.
[0007] The invention also provides the use of the device as defined
above for restricting the loss of blood during a surgical procedure
on the human or animal body.
[0008] According to another aspect of the present invention, there
is provided, in the surgical treatment of the human or animal body,
a method of controlling excessive bleeding, the method comprising
inserting an array of needles into the tissue or organ being
treated; and applying microwave energy to the region undergoing
treatment for a time sufficient to raise the temperature of said
tissue or organ by 20-30 degrees C.
[0009] Conveniently, the source of microwave radiation is in the
form of a rectangular waveguide whose dimensions correspond to
those of the tissue volume which is to be heated. The waveguide is
preferably generally rectangular in form, the array of retractable
needles being positioned around the periphery of the waveguide.
[0010] The device may include a needle advance mechanism including
a collar to which the needles are secured; movement of said collar
may be actuated by a solenoid mechanism.
[0011] In operation of the device, the needles will be advanced
from the body of the applicator into the tissue which is to be
heated so that the needles function as a extension of the
waveguide; in this way, the applicator will direct the required
microwave energy into the appropriate tissue volume prior to
surgery. When the heating process is completed, the needles are
retracted back into the body of the applicator.
[0012] Generally, the needles will be disposed mutually parallel;
they can conveniently be formed of steel.
[0013] Theoretical calculations show that, in order to raise the
temperature of body tissues by 30.degree. C., an applicator
operating with 100% efficiency would need to deliver about 10 watts
of microwave power, assuming that the volume to be heated is 40
cm.sup.3. For a typical biological tissue such as muscle, this
temperature rise would be achieved in approximately 10 minutes. If
the source is increased in energy to 500 watt, and if the
applicator is assumed to be about 80% efficient, the time taken to
achieve this required temperature increase is approximately 15
seconds.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] For a better understanding of the invention, and to show how
the same may be carried into effect, reference will now be made, by
way of example, to the accompanying drawings, in which:
[0015] FIG. 1 is a schematic representation of an applicator in
accordance with this invention;
[0016] FIG. 2 is a cross-sectional view of the applicator head of
FIG. 1;
[0017] FIG. 3 is an end elevational view corresponding to FIGS. 1
and 2.
DETAILED DESCRIPTION
[0018] Referring now to the drawings, a power and control unit (1)
supplies up to 500 watts of microwave power via a coaxial cable (2)
to a rectangular applicator (3). The head (3) has a handle (4)
through which cable (2) passes, and an array (5) of retractable
needles which are designed to provide precise irradiation of the
tissue in the vicinity of the selected incision point. The unit (1)
also contains a switching mechanism and control electronics to
energise and release the array of needles.
[0019] As shown in FIGS. 2 and 3, the applicator head (3) includes
a rectangular waveguide (6) around the periphery of which the
needles of array (5) are located. The waveguide is a TM.sub.11 mode
waveguide and is filled with a suitable dielectric. For irradiation
of a region 5 cm long by 2 cm wide, the rectangular waveguide
should have corresponding dimensions and may be filled with a
medium whose dielectric constant (.di-elect cons..sub.x) is about
50. These parameters dictate that the microwave operating frequency
should be of the order of 1 GHz. The specific values given here are
by of example only; it will be appreciated that a range of
applicators designed to irradiate different volumes of tissue may
be developed and these, of necessity, will have different
dimensions and may require a different dielectric medium and a
different operating frequency from that given above. In the
illustrated embodiment, each of the needles is 3 cm long and made
of steel. When the applicator is in operation, these needles will
be advanced into the tissue where they function as an extension to
the waveguide. A typical needle array may comprise about 20
needles. By employing a TM mode waveguide, leakage of energy
through the "needle wall"--i.e., the area bounded by the array of
needles--is kept to a low level (typically less than 10%) .
[0020] FIG. 2 also shows a collar (8) to which each of the needles
of the array (5) are secured. Collar (8) is acted upon by spring
(9) which forms part of a solenoid mechanism (10) for controlling
the advance and retraction of the array of needles. Power is
supplied to the solenoid mechanism (10) via cable (11). As
illustrated in FIG. 2, coaxial line (2) terminates within the
dielectric-filled waveguide (6).
[0021] In operation, a surgeon will position the applicator head
(3) against the region of tissue (e.g. liver) which is about to be
incised. Initially the needle array (5) is retracted within head
(3). When the applicator is actuated, solenoid mechanism (10)
causes the needles of array (5) to be extended into the patient's
tissue. Once they are embedded in the tissue, microwave energy at
the desired frequency (e.g. 1 GHz) is supplied to waveguide (6) and
passes therefrom into the volume of tissue enclosed by the array
(5) of needles. Energy is supplied at a typical power level of 500
watts for a duration of about 15 secs when an applicator of the
dimensions 5 cm.times.2 cm and a needle length of 3 cm is used. At
the end of the treatment period, the microwave source is switched
off and needle array (5) is retracted. The surgeon may then proceed
with the incision and any subsequent procedures as may be
necessary.
[0022] Blood loss from incision of tissue after heat treatment as
described is greatly reduced in comparison to the results obtained
in the absence of such heat treatment.
* * * * *