U.S. patent number 3,794,041 [Application Number 05/203,138] was granted by the patent office on 1974-02-26 for gastrointestinal catheter.
This patent grant is currently assigned to Yeda Research and Development Co. Ltd.. Invention is credited to Ephraim H. Frei, Shmuel Yerushalmi.
United States Patent |
3,794,041 |
Frei , et al. |
February 26, 1974 |
GASTROINTESTINAL CATHETER
Abstract
A gastrointestinal catheter of elongated shape, flexible and
including ferromagnetic material enabling it, when inserted into
the cavity of a body part, to be attracted by a magnet external of
the body in order to manipulate the body part with the catheter. In
the described embodiments, the ferromagnetic material is in the
form of beads enclosed within a tube of inert resilient material,
or strung on a string and coated with inert material.
Inventors: |
Frei; Ephraim H. (Rehovot,
IL), Yerushalmi; Shmuel (Rehovot, IL) |
Assignee: |
Yeda Research and Development Co.
Ltd. (Rehovot, IL)
|
Family
ID: |
22752674 |
Appl.
No.: |
05/203,138 |
Filed: |
November 30, 1971 |
Current U.S.
Class: |
606/108;
600/12 |
Current CPC
Class: |
A61M
25/0127 (20130101) |
Current International
Class: |
A61M
25/01 (20060101); A61m 025/00 () |
Field of
Search: |
;128/2M,25R,1.3,1.4,4-6,7,8,33R,348,349R,35R,356
;335/302,303,306 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Other References
Frei et al., - Med. Res. Engr. - Fourth Quar. 1966, pp.
11-18.
|
Primary Examiner: Truluck; Dalton L.
Claims
What is claimed is:
1. Magnetic apparatus insertable into a body cavity, for
displacement of internal body organs from a region of applied
radiation by means of a magnet disposed externally of the body,
characterized in that it is of elongated shape, flexible and
includes
an elongated flexible tubular member of substantially inert
resilient biologically acceptable material;
a plurality of ellipsoidal beads of soft iron having major and
minor axes substantially in a 2:1 ratio respectively, axially
disposed with their major axes parallel to the longitudinal axis of
said tubular member and in closely adjacent spaced relationship
therein over a substantial length thereof, said soft iron
ellipsoidal beads being fixed in said spaced relationship by said
resiliency of said flexible tubular member;
said magnetic apparatus being adapted when inserted into the cavity
of a body part, to be uniformly and unidirectionally attracted by a
magnet external of the body for desired displacement of said body
part as aforesaid substantially without the application of torque
to said beads.
2. Magnetic apparatus insertable into a body cavity, for
displacement of internal body organs as defined in claim 1, wherein
said flexible tubular member also includes plastic beads
alternating with and spaced from said soft iron beads and similarly
fixed in said spaced relationship by said resiliency of said
flexible tubular member.
Description
BACKGROUND OF THE INVENTION
The present invention relates to catheters insertable into a body
cavity, and particularly to gastrointestinal catheters for
insertion into a part of the intestinal tract, such as the
intestines.
In certain types of disease, the only effective treatment consists
of massive irradiation of the afflicted organ. This applies to many
cases of carcinoma of the cervix, of the bladder, of the ovary and
of the uterus, and also in similar diseases. One of the most
serious problems of such treatment is the high sensitivity of the
intestines to radiation damage, which seems to be due to the
continuous shedding by the small bowel cells of its lining, and to
the considerable mitotic activity of this organ.
BRIEF SUMMARY OF THE INVENTION
In order to make possible a massive irradiation of the afflicted
organs, while at the same time avoiding excessive irradiation of
the radiation-sensitive intestines, and especially the small bowel,
means are provided according to the present invention for moving
the intestines out of the path of the radiation when same is used
for irradiating the afflicted organs. The device according to the
invention is a special catheter which is inserted into the
intestines before the radiation treatment, which can be left in
place for some time in this position, and which makes it possible
to move the intestine out of the path of the irradiating beam.
The novel catheter made in accordance with the invention is
flexible and of elongated shape, and includes ferromagnetic
material enabling it, when inserted into the cavity of the body
part, such as the intestine, to be attracted by a magnet external
of the body, in order to manipulate the catheter and the body part
therewith.
Preferably, the ferromagnetic material is in the form of beads.
In one described embodiment, the ferromagnetic beads are enclosed
within a tube of inert resilient material, and in another described
embodiment they are strung on a flexible core, such as string, the
beads being coated with inert material.
Further features and advantageous of the invention will be apparent
from the description below.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention is herewith described, by way of example only, with
reference to the accompanying drawings, wherein:
FIG. 1 is a longitudinal sectional view of a part of a catheter
constructed in accordance with the invention;
FIG. 2 illustrates a variation in the catheter construction of FIG.
1; and
FIG. 3 illustrates another form of catheter constructed in
accordance with the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 1 illustrates a catheter particularly for insertion into the
intestines for moving the intestines out of the path of radiation
when the same is used for irradiating an afflicted organ
The catheter of FIG. 1 includes a hollow tube 2 of inert resilient
material and a plurality of members or beads 4 of iron or other
ferromagnetic material.
The length of the catheter is about one to several meters, and its
diameter is between 3 to 8 mm. The tubing 2 is of a biologically
acceptable material of adequate resilience, such as latex, silicon
rubber or the like, of adequate wall-thickness to provide some
degree of rigidity, yet supple enough to make it possible to follow
the turns and bends of the intestines when inserted in same. A wall
thickness of about 0.3 mm to 1.0 mm has proved satisfactory both
for silicon rubber and for natural latex tubing.
Within the tubing there is provided the plurality of spherical or
ellipsoid ferromagnetic beads 4 adapted to be strongly attracted by
a magnet. The outer diameter of these beads is chosen in such
manner that they are held in place by the resiliency of the tube 2.
It has been found that best results are obtained with oblong,
ellipsoidal beads having a ratio of radii of about 1:2.
The ratio of magnetisation to the magnetic field applied shows that
for prolate ellipsoids the best results are at a ratio of 1:2, as
indicated above. With ellipsoids of very elongated shape there is a
substantial torque, and this is a drawback for the intended use. No
problem of torque exists of course with spherical beads.
Very good results were obtained with iron ellipsoids of a ratio of
radii of about 1:2 of about 5 mm small diameter, inserted in a tube
of 7 mm outer diameter, of 1 mm wall-thickness, and of 2 meter
length.
According to a further embodiment of the invention as shown in FIG.
2; the external tube 12 includes a sequence of such iron beads 14
alternating with beads 16 of similar shape but of plastic material.
The beads are positioned close to each other in the tube and some
space is left if desired between the beads in order to facilitate
the bending of the tube. It is of course possible to use any
desired sequence of ferromagnetic beads 14 and of plastic beads 16,
and also to use such beads of slightly different radius or
shape.
According to a further embodiment of the invention as illustrated
in FIG. 3, the catheter comprises a plurality of ferromagnetic
beads 24 (if desired in a sequence with beads of plastic material)
of spherical or ellipsoid shape strung on a suitable core 28 of
string of adequate strength. Core 28 may also be a rod or hollow
member of plastic or the like of small diameter. The most simple,
yet satisfactory material for the spherical or ellipsoid beads is
soft iron, and this is advantageously coated with a coating of
plastic material 30 which is inert towards the environment of the
gastrointestinal tract and which is biologically acceptable. The
plastic coating 30 also reduces or eliminates the danger due to
secondary radiation which may result from the incidence of primary
radiation on the ferromagnetic beads, if the catheter or part of it
remains in the path of the primary radiation used for the treatment
of the patient.
The foregoing constructions provide an optimum of flexibility,
while at the same time avoiding a bunching together of several
members of the chain-like structure, either due to the peristaltic
movement or due to the combination of the peristaltic movement
together with the influence of the external magnetic force used to
move the part of the intestine into which the catheter is inserted
from the path of the radiation used for treatment.
First experiments were made by the direct introduction of ferrite
powder into the intestines of a dog. This experiment proved that it
is feasible to move the intestines by the application of an
external magnetic field on the ferrite contained in same. The loops
of the intestines could thus be moved sufficiently for the intended
results.
After having proved the feasibility of such movement, experiments
were continued with gastrointestinal catheters made of
ferromagnetic beads. In animal experiments the catheter was
inserted and soft X-rays to about 40 KV were used for monitoring
the movement of the intestinal loops due to the application of an
external magnetic field on such catheter. With guinea pigs a loop
of the intestine was moved by means of an external horseshoe magnet
and pulled towards the magnet in such manner that the external skin
was raised appreciably and pulled into the gap of the horseshoe
magnet. The animal was drugged and maintained in this position for
10 hours after which the magnet and the catheter were removed.
Histological examination showed no damage to the intestinal tissue.
The natural movement of the material in the intestines was not
affected by the presence of the catheter.
Further experiments were carried out with dogs. A catheter
according to FIG. 1 and comprising a plurality of iron beads of
ellipsoidal shape of 1:2 ratio of radii of 3 mm diameter (small
radius) in a silicon rubber tubing of 0.6 mm wall thickness was
inserted through the mouth or via a small incision made in the
small intestine. When a magnetic field was applied from the outside
of the body by means of a magnet having a field strength of 6,000
oersted at the face of the magnet, with a 2-inch iron core
diameter, this moved the catheter together with the intestine for a
sufficient distance.
Similar experiments were made with the FIG. 3 form of the catheter,
consisting of a plurality of plastic-coated iron ellipsoids strung
on a suitable string, and satisfactory results were obtained.
A number of experiments were carried out with humans. A
gastrointestinal catheter according to the FIG. 1 form of 1 meter
length and 3-7 mm outer diameter of the tubing ensheathing the iron
beads, was inserted into the intestines. The application of a
magnetic field from outside the body, of about 6 K-oersted moved
the catheter and the loop of the intestine in the desired
direction.
In the FIG. 3 form, the provision of a coating 30 of plastic, such
as polyethylene or the like, of adequate thickness, on the iron
beads prevents any secondary radiation from damaging the
intestines, if the catheter is in part in the path of the radiation
used for the treatment. In practice it is advisable to examine the
patient by X-rays prior to the radiation treatment in order to
ascertain that the loop or loops of the intestine, together with
the catheter inserted thereinto, have been moved away.
In guinea pig experiments Alnico 5 magnets were used as the
external magnets for attracting the catheter and the body part
therein. With humans it is advisable to use superconducting magnets
of great field strength and comparatively small size.
Catheters of about 4-7 mm outer diameter may be left in the
intestines for quite prolonged periods without any adverse effect.
Examinations carried out after 10 days showed that no damage was
caused by the catheter and that it did not interfere with the
natural body activities. During such prolonged periods it is
possible to carry out an intensive radiation treatment.
It is clear that the above description is by way of example only
and that many modifications, changes and other applications of the
catheters described may be made.
* * * * *