U.S. patent application number 13/548510 was filed with the patent office on 2013-01-10 for flexible application device for the high-frequency treatment of biological tissue.
Invention is credited to Kai DESINGER, Markus FAY, Andre ROGGAN, Thomas STEIN.
Application Number | 20130012940 13/548510 |
Document ID | / |
Family ID | 36952634 |
Filed Date | 2013-01-10 |
United States Patent
Application |
20130012940 |
Kind Code |
A1 |
DESINGER; Kai ; et
al. |
January 10, 2013 |
FLEXIBLE APPLICATION DEVICE FOR THE HIGH-FREQUENCY TREATMENT OF
BIOLOGICAL TISSUE
Abstract
The invention concerns a flexible application device including a
tubular high-frequency catheter with a flexible shaft tube having
at least one lumen passing therethrough, a head electrode arranged
at the distal end of the catheter, an electric line with a
connection for a generator ,and a connecting element arranged at
the proximal end of the shaft tube between the shaft tube and the
line. An electrically conducting traction element extends in the
lumen between the head electrode and the connecting element and is
fixedly connected to the head electrode on the one hand and the
connecting element on the other hand in such a way and which is of
such a tensile strength that all external forces which occur during
a treatment and which act on the catheter can be transmitted to the
connecting element by way of the head electrode and the traction
element.
Inventors: |
DESINGER; Kai; (Berlin,
DE) ; STEIN; Thomas; (Berlin, DE) ; ROGGAN;
Andre; (Berlin, DE) ; FAY; Markus; (Teltow,
DE) |
Family ID: |
36952634 |
Appl. No.: |
13/548510 |
Filed: |
July 13, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11920400 |
Jan 23, 2009 |
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PCT/EP2006/061762 |
Apr 21, 2006 |
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13548510 |
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Current U.S.
Class: |
606/50 ;
606/49 |
Current CPC
Class: |
A61B 2018/00023
20130101; A61B 18/148 20130101; A61B 2218/002 20130101; A61B
2018/00577 20130101; A61B 18/1492 20130101; A61B 2018/00029
20130101; A61B 2018/00011 20130101 |
Class at
Publication: |
606/50 ;
606/49 |
International
Class: |
A61B 18/14 20060101
A61B018/14 |
Foreign Application Data
Date |
Code |
Application Number |
May 13, 2005 |
DE |
10 2005 023.303.1 |
Claims
1. A method for medical treatment of a body part of a patient by
high frequency coagulation, comprising the steps of: a) introducing
a counterpart electrode into a body of the patient, the counterpart
electrode being configured for electrical association with a head
electrode; b) introducing a high-frequency element, having the head
electrode configured for coagulation treatment, into proximity with
the body part; c) applying a high frequency ac voltage with the
head electrode to the body part at a voltage sufficient to effect a
coagulation thereof; d) withdrawing the high frequency element from
proximity with the body part with, if necessary, continued
coagulation of a length of the body part by the high frequency ac
voltage on the body part, for an extent, as needed for the medical
treatment.
2. The method of medical treatment of claim 1, wherein the body
part is a blood vessel vein, the medical treatment is of varicose
veins, and the high-frequency element comprises a high frequency
catheter, with the method comprising the steps of: a) introducing
the counterpart electrode into the body of the patient; b) opening
a blood vessel vein in the proximity of an ankle of the patient; c)
introducing the high frequency catheter with its distal end, having
the head electrode, leading into the opened vein and advancing the
distal end to an end of the vein; d) after the distal end, with the
head electrode is positioned, applying high-frequency ac voltage to
the electrode and applying the electrode to the end of the vein to
effect coagulation and contraction of the vein; e) contracting the
vein over a desired length by the coagulation, with the distal end
of the catheter being retracted in a proximal direction at a speed
adapted to the dimensions and geometry of the vein being treated
and the extent of applied high-frequency ac voltage; and removing
the head electrode from the vein being treated, with the electrodes
being separated from the high frequency ac voltage, and the
high-frequency catheter being withdrawn from the patient's
body.
3. The method of claim 2, wherein, the high-frequency catheter is
bipolar, and a proximal ring electrode is associated therewith as
the counterpart electrode with the high-frequency ac voltage being
applied between the head electrode and the associated proximal ring
electrode.
4. The method of claim 2, wherein blood, which is in the vein, is
pressed out over the entire length of the vein prior to the
application of the high-frequency ac voltage.
5. The method of claim 2, wherein the position of the electrode
head at the distal end of the high-frequency catheter within the
vein, during coagulation, is estimated by at least one of
sonographic imaging, palpitation, and a tensioned cord, which is
positioned in parallel relationship with the high-frequency
catheter in such a way that either an end or a marked position of
the cord, outside the patient's body, is approximately level with
the head electrode within the patient.
6. The method of claim 2, wherein an acoustic or optical signal
dependent on the impedance between the head electrode and the
counterpart electrode is used to control speed of the withdrawal of
the high-frequency catheter and the magnitude of the high-frequency
ac voltage, as required.
7. The method of claim 1, wherein the body part is a Fallopian
tube, the medical treatment is the constriction or sclerosing of
the Fallopian tube for effecting sterilization and the high
frequency element comprises an hysteroscope, wherein the method
comprises the introducing of the head electrode from a uterus of a
female patient into the Fallopian tube by means of the hysteroscope
and coagulating regions of the Fallopian tube therewith to form a
contracted diameter and a closing thereof.
8. The method of claim 1, wherein the high frequency catheter is
introduced into a working passage of an endoscope for
interstitial-endoscopic operation and then advancing the high
frequency catheter into proximity with a body part, for the medical
treatment.
9. The method of claim 8, wherein the high frequency catheter is
advanced as far as a treatment location and then penetrated into
tissue to be treated, with the tissue being destroyed with the
application of the high frequency ac voltage.
10. The method of claim 9, wherein the medical treatment is the
treatment of a pancreatic tumor and the endoscope is a flexible
endoscope, wherein the method comprises the steps of: a)
introducing the high frequency catheter into a stomach of the
patient through a working passage of the flexible endoscope, and
fitting the high frequency catheter to a stomach wall over a
pancreas; b) puncturing the pancreas with the catheter while
monitoring the puncture site with a sonograph; and c) destroying
the pancreatic tumor by coagulation thereof with the application of
the high frequency ac voltage thereto.
11. The method of claim 9, wherein the medical treatment is the
treatment of a bronchial tumor blocking a bronchus and the
endoscope is a bronchoscope, wherein the method comprises the steps
of: a) introducing the high frequency catheter into the bronchus of
the patient through a working passage of the bronchoscope, and
placing a distal end tip of the high frequency catheter in front of
the tumor; b) puncturing the tumor at least once with the distal
end tip; and c) applying high frequency ac voltage to tissues of
the tumor with each puncture to coagulate the bronchial tumor
tissue to reduce volume of the tumor tissue and increase of cross
section of obstruction-free passage in the bronchus.
12. The method of claim 9, wherein the medical treatment is the
treatment of an obstructive tumor in or on a bile duct and the
endoscope is a gastroscope, wherein the method comprises the steps
of: a) introducing the high frequency catheter into the bile duct
of the patient through a working passage of the gastroscope, and
placing a distal end tip of the high frequency catheter in front of
the tumor; b) puncturing the tumor at least once with the distal
end tip; c) applying high frequency ac voltage to tissues of the
tumor with each puncture to coagulate the bile tumor tissue to
reduce volume of the tumor tissue and increase of cross section of
obstruction fee passage in the bile duct; and d) inserting a stent
into the bile duct to effect immediate drainage of bile fluid.
13. The method of claim 9, wherein the medical treatment is the
treatment of gastro-esophageal reflux disease (GERD, wherein the
method comprises the steps of: a) introducing the high frequency
catheter into a stomach entrance sphincter of the patient through a
working passage of the endoscope,; b) placing a distal end tip of
the high frequency catheter at an angle of between 30-90.degree. at
a level of the sphincter; c) advancing the head electrode to
penetrate into the sphincter tissue; d) applying high frequency ac
voltage to the sphincter tissue to coagulate the sphincter tissue
to thereby constrict the stomach entrance and to prevent or retard
reflux of gastric acid into the esophagus through the stomach
entrance.
14. A method for medical treatment of a body part of a patient by
high frequency coagulation, comprising the steps of: a) introducing
a counterpart electrode into a body of the patient, the counterpart
electrode being configured for electrical association with a head
electrode; b) introducing a high-frequency element, having the head
electrode configured for coagulation treatment, into proximity with
the body part; c) applying a high frequency ac voltage with the
head electrode to the body part at a voltage sufficient to effect a
coagulation thereof; d) withdrawing the high frequency element from
proximity with the body part with, if necessary, continued
coagulation of a length of the body part by the high frequency ac
voltage on the body part, for an extent, as needed for the medical
treatment wherein the high frequency catheter is introduced into a
working passage of an endoscope for interstitial-endoscopic
operation and then advancing the high frequency catheter into
proximity with a body part, for the medical treatment, wherein the
high frequency catheter is advanced as far as a treatment location
and then penetrated into tissue to be treated, with the tissue
being destroyed with the application of the high frequency ac
voltage, wherein the medical treatment is the treatment of a
bronchial tumor blocking a bronchus and the endoscope is a
bronchoscope, and wherein the method comprises the step of
puncturing the tumor at least once with a distal end tip of the
high frequency catheter.
15. A method for medical treatment of a body part of a patient by
high frequency coagulation, comprising the steps of: a) introducing
a counterpart electrode into a body of the patient, the counterpart
electrode being configured for electrical association with a head
electrode; b) introducing a high-frequency element, having the head
electrode configured for coagulation treatment, into proximity with
the body part; c) applying a high frequency ac voltage with the
head electrode to the body part at a voltage sufficient to effect a
coagulation thereof; d) withdrawing the high frequency element from
proximity with the body part with, if necessary, continued
coagulation of a length of the body part by the high frequency ac
voltage on the body part, for an extent, as needed for the medical
treatment, wherein the high frequency catheter is introduced into a
working passage of an endoscope for interstitial-endoscopic
operation and then advancing the high frequency catheter into
proximity with a body part, for the medical treatment, wherein the
high frequency catheter is advanced as far as a treatment location
and then penetrated into tissue to be treated, with the tissue
being destroyed with the application of the high frequency ac
voltage, wherein the medical treatment is the treatment of an
obstructive tumor in or on a bile duct and the endoscope is a
gastroscope, and wherein the method further comprises the step of
puncturing the tumor at least once with distal end tip of the high
frequency catheter.
16. A method for medical treatment of a body part of a patient by
high frequency coagulation, comprising the steps of: a) introducing
a counterpart electrode into a body of the patient, the counterpart
electrode being configured for electrical association with a head
electrode; b) introducing a high-frequency element, having the head
electrode configured for coagulation treatment, into proximity with
the body part; c) applying a high frequency ac voltage with the
head electrode to the body part at a voltage sufficient to effect a
coagulation thereof; d) withdrawing the high frequency element from
proximity with the body part with, if necessary, continued
coagulation of a length of the body part by the high frequency ac
voltage on the body part, for an extent, as needed for the medical
treatment, wherein the high frequency catheter is introduced into a
working passage of an endoscope for interstitial-endoscopic
operation and then advancing the high frequency catheter into
proximity with a body part, for the medical treatment, wherein the
high frequency catheter is advanced as far as a treatment location
and then penetrated into tissue to be treated, with the tissue
being destroyed with the application of the high frequency ac
voltage, wherein the medical treatment is the treatment of an
obstructive tumor in or on a bile duct and the endoscope is a
gastroscope, and wherein the method further comprises the step of
inserting a stent into the bile duct to effect immediate drainage
of bile fluid.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This is a continuation application of U.S. patent
application Ser. No. 11/920,400, filed Jan. 23, 2009, which is a 35
U.S.C. .sctn.371 national phase conversion of PCT/EP2006/061762,
filed Apr. 21, 2006, which claims priority to German Patent
Application No. 10 2005 023 303.1, filed May 13, 2005, the contents
of which are incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] The invention concerns a flexible application device for the
high-frequency therapy of biological tissue. The application device
includes a tubular high-frequency catheter with a preferably
flexible shaft tube which has at least one lumen therethrough and
which fits to or in a connecting element, and at least one head
electrode arranged at the distal end of the high-frequency
catheter.
[0003] In particular the invention concerns an application device
for endoluminal or interstitial-endoscopic use.
[0004] Application devices for high-frequency therapy are known.
During such a therapy procedure applying a high-frequency ac
voltage between two electrodes provides for a thermal in-depth
heating effect in respect of the tissue surrounding the electrodes.
The so-called active regions of the electrodes are in electrically
conductive relationship with the body tissue after being introduced
into the body of the patient. The ohmic tissue resistance which is
a part of the complex tissue impedance provides for conversion of
the alternating current applied by way of the electrodes into Joule
heat. At temperatures of between 50.degree. C. and 100.degree. C.,
denaturing of the body-specific proteins occurs (coagulation) and
consequently the affected areas of tissue shrink or die off. By
virtue of the high current density at the active electrodes the
heating effect occurs predominantly in the region of those
electrodes so that local thermal application is possible.
[0005] U.S. Pat. No. 6,014,589, U.S. Pat. No. 6,036,687, U.S. Pat.
No. 6,071,277 and U.S. Pub. No. 2004/0162555 A1 disclose methods
and various devices for the high-frequency therapy of hollow
organs, in particular for the treatment of veins.
[0006] Application devices for the high-frequency therapy of or in
hollow organs of the general kind set forth include a tubular
high-frequency catheter with [0007] a flexible shaft tube having at
least one lumen passing therethrough, [0008] a head electrode
arranged at the distal end of the high-frequency catheter, [0009]
an electric line with a connection for a high-frequency generator,
and [0010] a connecting element between the shaft tube and the
line.
SUMMARY OF THE INVENTION
[0011] Now the object of the present invention is to provide an
application device of the general kind set forth, which affords a
greater degree of certainty and safety in use.
[0012] In accordance with the invention that object is attained by
a flexible application device for the high-frequency therapy of
biological tissue, which has a traction element which extends
between the head electrode and the connecting element and which is
fixedly connected to the head electrode on the one hand and the
connecting element on the other hand in such a way and the
cross-sectional area of which and the tensile strength of which are
such that all external forces which occur during a treatment and
which act on the high-frequency catheter can be transmitted into
the connecting element by way of the head electrode and the
traction element.
[0013] The invention is based on the realisation that, in the case
of conventional application devices, the external forces which
occur during a treatment and which act on the high-frequency
catheter are substantially transmitted to the connecting element by
way of external components of the application device. The external
component of the application device which usually include a
fluid-tight, electrically insulating casing are frequently made up
of a plurality of pieces in the longitudinal direction of the
high-frequency catheter so that there are a plurality of connecting
locations by way of which the external forces have to be
transmitted, as considered in the longitudinal direction of the
high-frequency catheter. Each of the connecting locations however
represents a potential weak point. That gives rise to the risk of
individual components of the high-frequency catheter coming loose
or even entirely tearing away, under a mechanical loading. That
problem is effectively obviated by a traction element which extends
continuously from the head electrode to the connecting element and
which is suitably fixedly secured to the head electrode on the one
hand and the connecting element on the other hand.
[0014] The shaft tube of the high-frequency catheter preferably
forms an electrically insulating casing which encloses the lumen or
is provided with such a casing.
[0015] In a preferred variant the head electrode is electrically
connected to an electrical contact location in the connecting
element by way of an electrically conducting feed line which
extends within the electrically insulating casing. In a
particularly preferred fashion that feed line forms the traction
element itself and thus involves a dual function of electrical
conductor and securing element. With a suitable choice in respect
of the feed line material and with suitable dimensioning the
mechanical demands on the traction element and the electrical
demands on the feed line can be equally fulfilled.
[0016] The feed line as the traction element is preferably of a
tensile strength of at least 1000 N/mm.sup.2 and of a diameter of
between 0.2 and 0.8 mm, particularly preferably being 0.4 mm. With
a diameter of 0.4 mm a traction element of that kind can transmit
tensile forces of more than 125 N from the head electrode to the
connecting element. That tensile force is sufficient to transmit
all external forces from the head electrode to the connecting
element, in the event of failure of all connecting locations
between the casing of the shaft tube and the electrodes as well as
between the potentially several electrodes and the respective
insulator elements. In that case the traction element functions as
a safety element. The external forces acting on the high-frequency
catheter upon being pulled out of the tissue are usually directed
in the longitudinal direction of the high-frequency catheter. The
head electrode carries those forces and passes them by way of the
traction element in the form of tensile forces to the connecting
element. In the event of failure of all connecting locations of the
external components of the high-frequency catheter, those external
components are still pulled like a string of beads on to the feed
line serving as the traction element and in that way are connected
together by the feed line. The external components of the
high-frequency catheter are prevented from slipping off by the head
electrode being of a diameter which prevents that.
[0017] Particularly preferably the tensile strength of the traction
element and the connection to the head electrode is in the range of
between 70 and 300 N.
[0018] The details relating to the tensile strength refer in the
context of this description to the maximum value of the tensile
stress for a respective material, which arises as a maximum value
R. out of a stress-strain curve which is ascertained in a tensile
test. The tensile strength is calculated from the quotient of a
maximum tensile force and the initial cross-section of the sample
(unit of measurement: N/mm.sup.2).
[0019] The above-mentioned preferred diameter of the feed line of
the head electrode in the range of between 0.2 and 0.8 mm, besides
an adequate maximum tensile force and good electrical conductivity,
also permits easy integration of the high-frequency catheter into
existing application devices. Furthermore lines of that diameter
guarantee a level of flexibility which is adequate for endoluminal
or interstitial-endoscopic application.
[0020] A particularly suitable material for the feed line as a
traction element is a rust-resistant metal such as titanium or
stainless steel. Those metals enjoy a suitably high level of
tensile strength and at the same time, by virtue of the
dimensioning of the diameter of the feed line, also afford adequate
electrically conductivity.
[0021] In a particularly preferred variant the feed line of the
head electrode consists entirely or in parts of stainless steel
which is also referred to as V2A steel. The material has a high
tensile strength and is biocompatible. In an alternative embodiment
the feed line can be a braided wire comprising a large number of
individual filaments of stainless steel. That also ensures the
flexibility of the high-frequency catheter, which is necessary for
the application--particularly with the above-mentioned preferred
diameters for the feed line. The choice of the material steel is
particularly preferred whenever the head electrode also consists of
steel at least in a connecting region of the feed line. In that
case a homogeneous and high-strength connection can be formed by
welding between the feed line and the head electrode, which also
withstands high mechanical loadings.
[0022] The coagulation volume of application devices is limited by
the tissue drying out after a certain application time due to
evaporation of the tissue fluid in the proximity of the electrodes
where temperatures of over 100.degree. C. occur. That drying-out
effect causes a rise in the specific resistance of the tissue. If
at least one electrode is completely enclosed by dried-out tissue,
that involves a rapid rise in the terminal impedance so that
further input of energy into the tissue is prevented. That is
equivalent to the application being broken off, even if the
high-frequency generator remains switched on.
[0023] Internal flushing of the high-frequency catheter with a
temperature-controlled medium (for example water) means that this
procedure can be avoided within certain limits. By means of an
internal fluid circuit the electrodes are permanently kept at the
temperature of the fluid flowing through the arrangement. When
choosing a fluid temperature which is ambient temperature, it is
already possible to prevent the tissue from heating up in the
proximity of the electrodes to such a degree that the tissue dries
out. The regions at the highest temperature which in the case of a
non-flushed high-frequency catheter are directly at the electrode
surface are displaced into deeper layers of the tissue. The tissue
in the proximity of the electrodes retains its water and
electrolyte content and thus does not lose in terms of electrical
conductivity. The consequence of this is that, even after long
application times and at high power levels, electrical energy can
be transformed into heat there.
[0024] Electrode temperature control is based on a counterflow
fluid circuit. In a preferred variant the traction element is in
the form of a tube in which the fluid is passed to the tip of the
high-frequency catheter and flows back along the electrodes to the
proximal end of the high-frequency catheter. The amount of fluid
which is pumped through the high-frequency catheter is between 10
and 100 ml per minute.
[0025] A further possible way of preventing the electric current
from breaking down due to a rise in impedance as a consequence of
tissue dehydration is open flushing. With that principle,
preferably electrically conducting fluid (for example physiological
saline solution) is pumped through small bores or slots at the
distal end of the high-frequency catheter (for example in the
electrodes or in the insulator which in a bipolar arrangement is
between the electrodes), into the tissue. In that situation,
preferably only very small amounts of fluid are discharged into the
tissue and at best only when dehydration begins or is present. For
that purpose control of the pump can be effected in
impedance-dependent fashion: when a rise in impedance is detected,
which is to be equated to tissue dehydration in the proximity of
the electrodes, then the pump delivers fluid until the impedance is
restored to a normal value. The amounts of fluid which are
delivered here in a pump procedure are a multiple less than in the
above-described closed fluid circuit and are for example between 10
and 200 ml per hour. The increase which can be achieved in the
electrical conductivity of the tissue can be adapted to the needs
involved not just by a variation in the flushing amount but also
the salt concentration of the solution.
[0026] Still other kinds of fluids can be used for the open
flushing principle.
Therapeutically Effective Fluid:
[0027] A therapeutically effective medicament can be injected
directly into the treatment location through small bores or slots
at the distal end of the high-frequency catheter. It is possible to
envisage here for example a chemotherapy medicament which
particularly well destroys the tumor cells which are heated by
means of high-frequency current or which leads to thermal
sensitisation of the tumor cells and thus increases the
effectiveness of the thermotherapy. It is however also possible to
inject a local anaesthetic into the tissue to be treated in order
to reduce the pain which occurs due to the increase in temperature
of the tissue after the high-frequency current is switched on.
Toxic Fluid:
[0028] It is known that local destruction of tumor cells can be
implemented by the injection of highly concentrated alcohol. In the
case of the invention the injection can be effected through small
bores or slots at the distal end of the high-frequency catheter and
supplement the thermotherapy effect. The delivery of a toxic
substance (such as for example high-percentage alcohol or a highly
concentrated salt solution) can also be effected after the
thermotherapy while the high-frequency catheter is being pulled out
of the tissue in order to avoid spreading tumor cells.
Mixture:
[0029] Finally a mixture of electrically conducting,
therapeutically effective and toxic fluids which can be adapted to
the respective treatment and optimised is also possible.
[0030] Preferably the application device is in the form of a
bipolar application device with a second proximal electrode which
is electrically insulated with respect to the head electrode. The
proximal electrode is arranged in the proximity of the distal end
of the high-frequency catheter and electrically conductingly
connected by way of a second electrical feed line to a second
contact location in the connecting element. The spacing between the
head electrode and the proximal electrode is preferably between 5
and 20% of the electrode length (with a bipolar configuration that
corresponds to the overall length of distal and proximal
electrodes). That spacing has proven to be particularly suitable
for tissue sclerosis by means of a high-frequency alternating
current.
[0031] The diameter of the high-frequency catheter, in particular
the outside diameter of the shaft tube and the outside diameter of
the proximal electrode and the largest diameter of the head
electrode are preferably approximately equal to each other. In that
respect the head electrode is preferably of its largest diameter at
the proximal end of its outwardly directed peripheral wall. The
head electrode is for example of a hemispherical shape towards its
distal end. As an alternative thereto it can have a trocar ground
configuration or can be pointed in a conical or wedge-shaped
configuration.
[0032] The largest diameter of the head electrode and the diameter
of the proximal electrode and of the rest of the high-frequency
catheter is preferably less than 3.5 mm.
[0033] In regard to preferred uses the length of the shaft tube is
between 300 and 3000 mm. The traction element passing therethrough
is also to be of a corresponding length.
[0034] An application device of that kind is suitable for known
uses and in addition embraces new therapy methods and areas of
application.
Endoluminal use of the Device:
[0035] For endoluminal use the high-frequency catheter of the
application device is introduced into the lumen of a hollow organ,
in particular a vessel. A high-frequency ac voltage is then applied
to the electrodes. The position of the electrodes in the hollow
organ can be altered by pushing it forward and pulling it back or
by reciprocating it or by a rotary movement about its own axis.
[0036] For endoluminal use the head electrode is rounded and is
shorter in terms of its longitudinal extent than the proximal
electrode. The diameter of the high-frequency catheter of an
application device for endoluminal use is to be adapted to the
diameter of the hollow organ or vessel to be treated. In an
endoluminal use the hollow organ to be treated, in particular the
vessel wall, has current flowing therethrough, it heats up and
coagulates. The hollow organ or the vessel consequently reduces its
inside diameter or is completely closed.
Operating Procedure using the Example of Varicose Veins:
[0037] A blood vessel to be treated, preferably the Vena saphena
magna, is firstly preferably opened in the proximity of the ankle.
The high-frequency catheter is then introduced with its distal end
leading into the opened vein and advanced to the end of the vein.
In the case of the Vena saphena magna that is the transition to the
Vena formoralis. Optionally the Vena saphena magna can also be
separated from the Vena formoralis (crossectomy) and the electrode
advanced until it becomes visible at that opening. In that case, no
high-frequency ac voltage leading to coagulation is yet applied to
the electrode or electrodes of the high-frequency catheter. If no
crossectomy is performed the position of the electrode head at the
saphenofemoral transition is preferably monitored with sonographic
imaging.
[0038] After the distal end of the high-frequency catheter with the
head electrode is correctly positioned, a high-frequency ac voltage
can be applied to the electrode provided for the treatment, and
that voltage causes coagulation. In a monopolar arrangement the
electrode intended for the treatment is the head electrode at the
distal end of the high-frequency catheter. A counterpart electrode
is previously applied to the body of the patient, as a neutral
electrode of large area. If in accordance with a preferred variant
a bipolar high-frequency catheter is used the high-frequency ac
voltage is applied between the head electrode and the associated
proximal ring electrode.
[0039] In order to contract the blood vessel over the desired
length by coagulation the high-frequency catheter is then retracted
slowly in the proximal direction. In that case the working speed is
adapted to the geometry of the blood vessel to be treated and to
the applied high-frequency ac voltage.
[0040] To increase the therapy effect, before the high-frequency ac
voltage is applied, the blood which is in the vein can be pressed
out with a cuff over the entire length of the vein.
[0041] In order to be able to approximately estimate the position
of the electrode head at the distal end of the high-frequency
catheter during the coagulation procedure (return movement), it is
advantageous if a cord is tensioned in parallel relationship with
the high-frequency catheter from the connecting element of the
application device, in such a way that the end of the cord or a
marked location on the cord outside the body of the patient is
approximately level with the head electrode within the patient. In
that fashion the high-frequency catheter can be retracted in the
proximal direction particularly sensitively and at a uniform speed.
Further possible options in regard to positional monitoring are
sonographic imaging and palpation.
[0042] As soon as the head electrode leaves the portion to be
treated of a blood vessel, the electrodes are separated from the
high-frequency ac voltage again and the high-frequency catheter can
be entirely withdrawn from the body of the patient.
[0043] If the application device is connected to a suitable control
unit, the high-frequency ac voltage can be adapted to the
respective demands involved, during coagulation. If the control
unit is such that it outputs for example an acoustic or optical
signal dependent on the impedance between the head electrode and
the counterpart electrode, both the speed of withdrawal of the
high-frequency catheter and also the magnitude of the
high-frequency ac voltage can be particularly easily adapted to the
respective requirements.
Operating Procedure Using the Example of the Fallopian Tube:
[0044] A further area of use of an application device with
endoluminal involvement lies in the constriction or sclerosing of a
Fallopian tube for sterilisation purposes. The electrode is
introduced from the uterus into the Fallopian tube to be closed by
means of a hysteroscope (endoscope for gynecology). The further
procedure is the same as that of constricting veins (see above):
after correct positioning of the electrode within the Fallopian
tube high-frequency current is delivered and the electrode is
retracted by a given distance so that the coagulated region
contracts in respect of diameter and is thereby closed.
Interstitial-Endoscopic Use:
[0045] For interstitial-endoscopic use the high-frequency catheter
of the application device is introduced into a working passage of
an endoscope and advanced as far as the treatment location in order
there to penetrate into the tissue to be treated and to destroy the
tissue when an ac voltage is applied, as a consequence of
coagulation. The use can be implemented for example with
sonographic monitoring.
[0046] For interstitial-endoscopic use the head electrode
preferably involves a conical or trocar grind. In addition
preferably the electrode surface is at least region-wise of such a
nature that the reflection of ultrasound is enhanced in order to
facilitate sonographic monitoring of the application. Finally the
application device, in an interstitial-endoscopic use, preferably
has a guide tube or guide system. For interstitial-endoscopic use
the diameter of the high-frequency catheter must be matched to the
diameter of the working passage of the endoscope.
Treatment Procedure Using the Example of Pancreatic Tumors:
[0047] An area of use of an application device with
interstitial-endoscopic involvement is the treatment of pancreatic
tumors (pancreatic carcinomas). For that purpose the tubular
high-frequency catheter of the application device is introduced
into the stomach by way of a working passage of a gastroscope
(endoscope for the gastrointestinal area) and fitted to the stomach
wall over the pancreas. The pancreatic tumor is punctured with
sonographic monitoring (endoscopic ultrasound) and the tumor tissue
destroyed by coagulation.
Treatment Procedure Using the Example of Bronchial Tumors:
[0048] A further area of use of an application device with
interstitial-endoscopic involvement is the treatment of bronchial
tumors. For that purpose the high-frequency catheter is introduced
into the bronchus in question through a bronchoscope (endoscope for
the bronchial region) and placed with the distal end in front of
the tumor. The tumor--which for example can obstruct the bronchus
and thereby prevent the supply of respiratory air in the adjoining
region--is punctured one or more times with the tip, which is
introduced into a working passage of the bronchoscope, of the
tubular high-frequency catheter, a high-frequency ac voltage being
applied each time. The tissue of the bronchial tumor coagulates.
The reduction in volume in the tumor tissue, which is caused by the
coagulation effect, should lead in particular to an increase in
cross-section with the obstruction to the bronchus being
removed.
Treatment Procedure Using the Example of Tumors on the Bile
Duct:
[0049] A further area of use of an application device with
interstitial-endoscopic involvement is the treatment of obstructive
tumors in or on the bile duct (ductus choledochus). The individual
steps in the treatment are to be carried out with a gastroscope
similarly to the treatment of obstructive bronchial tumors. The
high-frequency catheter is introduced into the bile duct through a
gastroscope (endoscope for the gastrointestinal region) and placed
with the distal end in front of the tumor. The tumor which
obstructs the bile duct is punctured one or more times with the
tip, introduced into a working passage of the gastroscope, of the
tubular high-frequency catheter, with a high-frequency ac voltage
being applied on each occasion in order to coagulate the tumor
tissue. Then at that location a stent (tubular element with which a
lumen is safeguarded against obstruction) can be inserted into the
bile duct, whereby immediate drainage of the bile fluid is made
possible.
Treatment Procedure Using the Example of Gastro-Esophageal Reflux
Disease:
[0050] Finally the application device with interstitial-endoscopic
involvement of the application device is suitable for the treatment
of gastro-esophageal reflux disease (GERD). For that purpose the
high-frequency catheter of the application device is passed to the
stomach entrance (sphincter) by way of an endoscope. The distal end
of the endoscope is angled at the level of the sphincter through
about 30-90.degree., the electrode is advanced and caused to
penetrate into the sphincter tissue. Thereupon high-frequency
current is delivered in order to coagulate the tissue. The healing
process induced thereby leads to a constriction of the stomach
entrance and reflux of gastric acid into the esophagus is prevented
or reduced.
BRIEF DESCRIPTION OF THE DRAWING(S)
[0051] The invention is described in greater detail hereinafter by
means of an embodiment by way of example and with reference to the
accompanying drawings in which:
[0052] FIGS. 1a and 1b show an application device according to the
invention with an enlarged illustration of its distal end,
[0053] FIG. 2 shows a head electrode with a traction element which
at the same time serves as an electrical feed line,
[0054] FIGS. 3a and 3b show a diagrammatic view in section by way
of example on an enlarged scale of a closed fluid circuit of a
variant of the distal end of the application device according to
the invention, and
[0055] FIGS. 4a and 4b show a diagrammatic view in section by way
of example on an enlarged scale of an open fluid flushing
arrangement of a variant of the distal end of the application
device according to the invention.
DETAILED DESCRIPTION OF THE INVENTION
[0056] FIG. 1a shows a flexible application device 1 which is
suitable for the high-frequency therapy of biological tissue. The
application device 1 includes a connecting element 8, in the
interior of which is disposed the electrical and mechanical
interface between the cable 9 and the lines within the
high-frequency catheter 5.
[0057] At its proximal end 10 the connecting element 8 has a
through passage, through which a cable 9 is passed. The cable 9 is
connected by way of the connection 20 to the supply and control
unit 11 with which a high-frequency ac voltage can be generated in
per se known manner.
[0058] At the distal end 7 of the connecting element 8 a flexible
tubular high-frequency catheter 5 is passed through a suitable
opening into the interior of the connecting element 8 and fixed
there.
[0059] The high-frequency catheter 5 includes a shaft tube 6 with a
lumen extending therethrough. The casing of the shaft tube 6 is
formed from an elastic material, for example a polymer, in
particular PEEK.
[0060] In addition the high-frequency catheter 5--arranged in
succession in the distal direction starting from the connecting
element 8--has a proximal electrode 4, an insulator 3 and a head
electrode 2 arranged at the distal end of the high-frequency
catheter 5.
[0061] In the illustrated embodiment the head electrode 2 has a
rounded head and is therefore particularly suitable for endoluminal
use. For interstitial-endoscopic purposes of use the head electrode
2 can be pointed at its distal end and preferably has a trocar
grind or is pointed in a wedge-shaped or conical configuration.
[0062] FIG. 1b shows a view on an enlarged scale of the distal end
of the application device 1 according to the invention. The
traction element 12 for the head electrode 2 is passed centrally
through the shaft tube 6 and, being electrically insulated with
respect to the proximal electrode 4, goes to the proximal end 13
(see also FIG. 2) of the head electrode 2. The traction element 12
is in the form of a metal wire which preferably comprises stainless
V2A steel. To increase flexibility it can be in the form of a
braided metal cable. For the purposes of electrical insulation the
wire can be partially sheathed with a non-conducting material. The
traction element 12 is fixedly connected with its distal end at the
proximal end 13 of the head electrode 2, preferably by welding. The
head electrode 2 also comprises V2A steel at least in the region of
its proximal end 13. The traction element 12 has a tensile strength
of at least 1000 N/mm.sup.2. In the described embodiment the
traction element 12 of the head electrode 2 is of a diameter of 0.4
mm. Proximally, the traction element 12 is mechanically stably
connected to the connecting element 8 and electrically conductingly
connected to the cable 9 within the connecting element 8.
[0063] An electrical feed line (not described in greater detail
herein) is passed through the lumen of the shaft tube 6 to the
proximal electrode 4. The feed line is electrically conductingly
connected to the cable 9 within the connecting element 8. The
electrical feed line for the proximal electrode 4 comprises for
example copper and is sheathed with an insulator material.
[0064] FIG. 2 shows the head electrode 2 with a traction element
12. The traction element 12 is fixedly connected with its distal
end at the proximal end 13 of the head electrode 2, preferably by
being welded thereto. The head electrode 2 also comprises V2A steel
at least in the region of its proximal end 13.
[0065] To increase coagulation efficiency the high-frequency
catheter 5 can also be provided with an electrode temperature
control means. For that purpose in a variant a flushing tube
(hollow) is arranged over the traction element 12. In addition, in
a variant, the traction element 12 may not be in the form of wire
(solid material) but in the form of a tube (hollow). Those variants
will be described in greater detail hereinafter with reference to
FIGS. 3a, 3b, FIGS. 4a and 4b.
[0066] FIGS. 3a and 3b show a diagrammatic view in section on an
enlarged scale by way of example of a closed fluid circuit
(counterflow principle) of the distal end of the application device
according to the invention.
[0067] As shown in FIG. 3a a flushing tube 19 is arranged over the
traction element 12. Fluid 17 is pumped through the internal lumen
18 of the flushing tube 19 to the distal end of the high-frequency
catheter 5, passes through the open distal end of the flushing tube
19 into the space 16 between the flushing tube 19 and the head
electrode 2, the insulator 3, the proximal electrode 4, the shaft
tube 6 and flows back to the proximal end of the high-frequency
catheter 5. The flushing tube 19 preferably comprises a
non-conducting flexible material.
[0068] FIG. 3b shows a variant in which the traction element 12 is
not in the form of wire (solid material) but in the form of a tube
(hollow). Fluid 17 is pumped through the internal lumen 15 of the
traction element 12 to the distal end of the high-frequency
catheter 5, passes through the transverse bores 14 into the space
16 between the traction element 12 and the head electrode 2, the
insulator 3, the proximal electrode 4 and the shaft tube 6 and
flows back to the proximal end of the high-frequency catheter 5. In
this variant the traction element 12 preferably comprises a
conducting metal alloy such as NiTiNol (alloy consisting of nickel
and titanium) or CuAlZn (alloy consisting of copper, aluminum and
zinc) or AuCd (alloy consisting of gold and cadmium) or FePt (alloy
consisting of iron and platinum).
[0069] Open flushing can be implemented in the case of
high-frequency catheters 5 of small outside diameter. This can be
effected in two variants (as shown in FIG. 4a and FIG. 4b):
[0070] FIGS. 4a and 4b show a diagrammatic view in section on an
enlarged scale by way of example of open fluid flushing of a
variant of the distal end of the application device according to
the invention.
[0071] Referring to FIG. 4a the traction element 12 to the head
electrode 2 is in the form of wire. The fluid 17 is pumped through
the space 16 between the traction element 12, the shaft tube 6, the
proximal electrode 4, the insulator 3 and the head electrode 2 and
issues through bores 14 or slots 14 in the head electrode 2. In a
further variant bores 14 or slots 14 can also be provided in the
proximal electrode 4.
[0072] Referring to FIG. 4b the traction element 12 to the head
electrode 2 is in the form of a flexible tube. The fluid 17 is
pumped through the internal lumen 15 of the traction element 12 to
the distal end and issues through bores 14 or slots 14 in the head
electrode 2. In this variant the traction element 12 preferably
comprises elastic and conducting metal alloys such as NiTiNol
(alloy consisting of nickel and titanium) or CuAlZn (alloy
consisting of copper, aluminum and zinc) or AuCd (alloy consisting
of gold and cadmium) or FePt (alloy consisting of iron and
platinum).
* * * * *