A cerebrospinal fluid shunt in the form of a ventricular catheter for controlling the condition of hydrocephalus by relieving the excessive cerebrospinal fluid pressure is described. A method for fabrication of the catheter and shunting the cerebral fluid from the cerebral ventricles to other areas of the body is also considered. Shunt flow failure occurs if the ventricle collapse due to improper valve function causing overdrainage. The ventricular catheter comprises a multiplicity of inlet microtubules. Each microtubule has both a large openings at its inlet end and a multiplicity of microscopic openings along its lateral surfaces

Banks, B. A.

English

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SUBJECT: Announcement of NASA-Owned U.S. Patents in STAR
In accordance with the procedures agreed upon by Code GP-4 and
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Th'e following information is provided:
U.S. Patent No. : 4,377,169
Government or
Contractor Employee:
NASA Case No. :
U.S. Government
LEW-13,107-1
NOTE - If this patent covers an invention made by a contractor
employee under a NASA contract, the following is applicable:
YES / / NO
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r{HASA-Case-LE8~ 13 107-1) JON
SPUTTER-ETCHED VENTRICULAR CATHETER FOR
HYDROCEPHALUS SHUNT Patent (HASA) 7 p
CSCL 06C
00/52
N83-21785
Unclas
11071
https://ntrs.nasa.gov/search.jsp?R=19830013514 2020-03-22T00:23:29+00:00Z
United States Patent
Banks
[ii] 4,377,169
[45] Mar. 22,1983
[54] ION BEAM SPUTTER-ETCHED
VENTRICULAR CATHETER FOR
HYDROCEPHALUS SHUNT
[76] Inventor: Bruce A. Banks, Olmsted Township,
Cuyahoga County, Ohio, granted to
Administrator of the National
Aeronautics and Space
Administration under the provisions
of42U.S.C. 2457(c)
Appl. No.: 272,407
Filed: Jun. 10, 1981
[21]
[22]
[51]
,[52]
[58]
[56]
Int. CU A61B 27/00
U.S. Q 604/8; 604/280
Field of Search 128/348-350
References Cited
U.S. PATENT DOCUMENTS
3,410,97911/1968 Larsson 219/68
3,437,088 4/1969 Bielmski 128/348
3,595,241 7/1971 Sheridan 128/350
3,656,988 4/1972 Steffen et al 117/5.5
3,753,439 8/1973 Brugarolas et al 128/350 R
3,823,720 7/1974 Tnbble 128/350 R
4,038,513 7/1977 Steigerwald 219/121 EM
4,072,153 2/1978 Swartz 128/350 R
4,083,369 4/1978 Smnreich 128/276
4,121,59510/1978 Heitmann 131/21 R
4,182,343 1/1980 Inaba 128/350 R
FOREIGN PATENT DOCUMENTS
2233028 6/1973 France 128/350 R
OTHER PUBLICATIONS
"A New Tissue Drain", W. Yeates, The Lancet,
12/1/62, p. 1150.
Primary Examiner—Kyle L. Howell
Assistant Examiner—Nancy A. B. Swisher
Attorney, Agent, or Firm—Norman T. Musial; John R.
Manning; Gene E. Shook
157] ABSTRACT
The ventricular catheter 10 of the present invention
comprises a multiplicity of inlet microtubules 12. Each
microtubule has both a large opening 16 at its inlet end
and a multiplicity of microscopic openings 18 along its
lateral surfaces.
The microtubules are perforated by a new and novel ion
beam sputter etch technique. The holes are etched in
each microtubule by directing an ion beam 20 through
an electro formed metal mesh mask 28 producing perfo-
rations having diameters ranging from about 14 microns
to about 150 microns.
This combination of a multiplicity of fluoropolymer
microtubes, the numerous small holes provided in the
lateral surfaces of the tubes, and the hydra-like distribu-
tion of the tubes provide a new and novel catheter. This
structure assures a reliable means for shunting cerebro-
spinal fluid from the cerebral ventncles to selected areas
of the body.
8 Claims, 6 Drawing Figures
U.S. Patent Mar. 22, 1983 Sheet 1 of 3 4,377,169
14
FIG.
26
FIG. 3
U.S. Patent Mar. 22, 1983 Sheet 2 of 3 4,377,169
FIG.4
—12
FIG. 5
U.S. Patent Mar. 22, 1983 Sheet 3 of 3 4,377,169
4,377,169
ION BEAM SPUTTER-ETCHED VENTRICULAR
CATHETER FOR HYDROCEPHALUS SHUNT
DESCRIPTION 5
Origin of the Invention
The invention described herein was made by an em-
ployee of the U.S. Government and may be manufac-
tured and used by or for the Government for govern-
 ]0
mental purposes without the payment of any royalties
thereon or therefor.
TECHNICAL FIELD
This invention is directed to an improved cerebrospi- j
 5
nal fluid shunt in the form of a ventricular catheter for
controlling the condition of hydrocephalus by relieving
the excessive cerebrospmal fluid pressure. The inven-
tion is further concerned with an improved method for
fabricating the catheter and an improved method of
shunting the cerebral fluid from the cerebral ventricles
to other areas of the body.
The obstruction of cerebrospinal fluid flow pathways
or its inadequate absorption via the arachnoid villi into
the venus blood of the brain results in hydrocephalus.
Surgical correction involves pressure controlled shunt-
ing of the cerebrospinal fluid. Typically, a perforated
silicon rubber catheter is implanted in one of the lateral
ventricles of the brain with its perforated tip located
near the frontal horn. The cerebrospinal fluid passes
through a pressure regulating valve and is then typi-
cally shunted to the right atrium of the heart or the
peritoneal cavity.
The shunt will fail to function if the inlet ventricular
catheter apertures become blocked. Shunt flow failure
will also occur if the ventricle collapses due to improper "
valve function causing over drainage.
Heretofore, previously designed ventricular catheters
have been found deficient as a result of high incidence
of inlet blockage caused by the ingrowth of the choroid
plexas, ventncal collapse over the catheter orifices, or ^
hemorrage, cellular, and fibrin debris. Multiple surgical
revisions during the first several years after birth is
common because of inlet blockage of the catheters.
Various geometry ventricular catheters have been
proposed in which the inlet orifices are hidden or cov- 45
ered by complicated structures. The hidden inlet type
geometries have not resulted in a decreased probability
of blockage.
Prior Art
25
50
In the prior art U.S. Pat. No. 4,182,343 discloses a
double ventricular drain tube having a double cavity. A
rubber outer tube has one end which is sealed with the
other end being open. This outer tube encloses a rubber
inner tube that is shorter than the outer tube. One end of 55
the inner tube is fixed to the inner wall of the sealed end
of the outer tube and the other end of the inner tube is
open. This inner tube may or may not be fixed to the
inner wall of the outer tube. The outer tube and the
inner tube, respectively, have a plurality of holes pass- 60
ing through their respective side walls. The holes
through the outer tube side wall are positioned in such
a manner so that they do not align with the holes in the
side wall of the inner tube.
U.S. Pat. No 3,595,241 discloses a medicosurgical 65
tube having a swab member positioned inside the tube
so constructed or arranged that it may be pulled
through the tube and out the proximal end. In such a
catheter, the lumen is positively protected throughout
the tube length against the possibility of blod clots or
other matter preventing liquid flow through the tube
following the tube insertion procedure.
U.S. Pat. Nos. 3,753,439 and 3,823,782 disclose sev-
eral types of surgical drains. These drains rely on rela-
tively large holes in the tube wall, and a padding or net
is utilized to prevent entry of material into the holes.
None of the prior art patents discloses a catheter which
would be suitable for insertion into the human brain.
DISCLOSURE OF INVENTION
The ventricular catheter of the present invention
comprises a multiplicity of inlet microtubules. Each
microtubule has both a large opening at its inlet end and
a multiplicity of microscopic openings along its lateral
surfaces.
The microtubules are perforated by a new and novel
ion beam sputter etch technique. The holes are etched
in each microtubule by directing an ion beam through
an electro formed metal mesh mask producing perfora-
tions having diameters ranging from about 14 microns
to about 150 microns.
This combination of a multiplicity of fluoropolymer
microtubes, the numerous small holes provided in the
lateral surfaces of the tubes, and the hydra-like distribu-
tion of the tubes provide a new and novel catheter. This
structure assures a reliable means for shunting cerebro-
spinal fluid from the cerebral ventricles to selected areas
of the body.
BRIEF DESCRIPTION OF THE DRAWINGS
The objects, advantages and novel features of the
invention will be more fully apparent from the follow-
ing detailed description when read in connection with
the accompanying drawings wherein
FIG. 1 is an enlarged view of a ventricular catheter
constructed in accordance with the present invention,
FIG. 2 is a schematic view showing apparatus for
perforating the walls of the microtubules utilized in the
catheter shown in FIG. 1.
FIG. 3 is an enlarged sectional view taken along the
lines 3—3 in FIG. 2,
FIG. 4 is a scanning electron photomicrograph show-
ing the outside surface of a sputter perforated microtu-
bule,
FIG. 5 is a scanning electron photomicrograph show-
ing a sputter perforated microtubule in section, and
FIG. 6 is a schematic view showing the direct shunt-
ing of cerebrospinal fluid from a lateral ventricle to the
subarachnoid space using sputter perforated microtu-
bules.
BEST MODE FOR CARRYING OUT THE
INVENTION
Referring now to the drawing there is shown in FIG.
1 a ventricular catheter 10 constructed in accordance
with the present invention. Each catheter 10 comprises
a plurality of pliable microtubules 12. A bundle of the
microtubules 12 may be covered by a tubular sheath 14
which is connected to a conventional valved shunting
system.
The microtubules 12 are of a fluoropolymer material
and can be vaned in number, diameter, wall thickness,
length and material. Typical fluoropolymers that are
satisfactory for the microtubules 12 are polytetrafluoro-
ethylene and fluoroethylene propylene. Living cells of
4,377,169
the human body tend not to adhere to such materials,
and no major anchorage problem results.
Each microtubule 12 has an inlet end 16 which is
preferably open and is of a larger diameter than each of
the multiplicity of ion beam sputtered microscopic per- 5
forations 18 along a relatively long extent of the lateral
surfaces as shown in greater detail in FIGS. 4 and 5. It
is further contemplated that the inlet end 16 may be
closed in certain embodiments.
The tubular sheath 14 is preferably of a silicone rub- 10
ber tubing of small diameter to minimize the penetration
thereby reducing the danger of infection. Silicon tubing
having an outer diameter of about 0.015 m has been
satisfactory. The type of transition from the fluorocar-
bon bundle to the silicone rubber tubing can be varied in 15
geometry.
Preselected areas of the microtubules 12 are perfo-
rated by exposing them to an ion beam 20 from a suit-
able source 22 as shown in FIG. 2. The ion beam 20 is
between 300 eV and 500 eV with a density sufficient to 20
perforate the microtubules 12 at a predetermined expo-
sure time as shown in FIGS. 4 and 5.
The argon ion beam may be from an electron bom-
bardment ion source 22 of the type developed from
electric propulsion technology. Such an ion source is 25
described in "Advances in Electronics and Electron
Physics" by H. R. Kaufman, Vol. 36, pages 365 to 373.
Beam extraction may be accomplished by a dished,
two grid ion optics system. Such a system is described
in AIAA Paper No. 76-1017 entitled "A 30 cm Diame- 30
ter Argon Ion Source". Neutralization of the ion beam
may be achieved by secondary electrons released by ion
bombardment of the walls of a vacuum facility (not
shown) which houses the ion source 22. This vacuum
facility is sufficiently large to minimize back sputtered 35
facility material from contaminating the material being
ion beam etched. The vacuum facility normally is main-
tained at a pressure of 4x 10~5 torr during the operation
of the ion source 22.
Microtubules 12 are mounted around the outer pe- 40
ripheral surface of a cylindrical mandrel 24 mounted for
rotation about is normal axis downstream from the ion
source 22. A suitable shield 26 is positioned between the
source 22 and the mandrel 24 in close proximity with
the mandrel. The ion beam 20 passes through the shield 45
26 in a manner well known in the art.
An electroformed screen 28 of extremely fine mesh is
held in tension around the outermost surface edges of
the microtubules 12 on the mandrel 24 as shown in FIG.
3. Argon ions from the beam 20 pass through the screen 50
28 to form a pattern of perforations 18 as shown in FIG.
4. More particularly, the electroformed metal mesh
screen 28 functions as a mask to produce the desired
apertures through the walls in the microtubules 12
These apertures 18 are microscopic in size, having a 55
diameter between about 14 f«n and 150 /j.m The por-
tion of the ion beam 20 passing through the shield 26 is
shown in FIG. 3 and is substantially uniform in density
throughout its entire width.
The utilization of sputter etching to perforate the 60
inlet ventricular catheter microtubules 12 facilitates the
fabrication of catheters having two orders of magnitude
increase in aperture density over that of conventional
catheters shown in the prior art. This is evident because
approximately 1100 apertures for each 20 p.m in diame- 65
ter can be placed along a 1 cm length of microtubule.
The catheter 10 is comprised of a bundle of one or
more microtubules 12, each being only about 0.44 mm
in diameter. The resulting large number of inlet aper-
tures reduces the tendency for the shunt to draw in and
trap debris or tissue which would then cause flow ob-
struction.
The catheter 10 can be used to drain cerebrospinal
fluid from one of the lateral ventricles through a con-
ventional valved shunting system to either the heart or
the peritonal cavity. The catheter also can be used for
direct shunting of cerebrospinal fluid from a lateral
ventricle 30 to selected areas of the human body using
individual microtubules 12 as shown in FIG. 6. This
lateral ventricle is in substantial justaposition with the
third ventricle 32 which is positioned above the fourth
ventricle 34.
The microtubules 12 extend from the lateral ventricle
up through the pia mater to the subarachnoid space 38.
This space is between the pia mater 36 and the arach-
noid 40 which is positioned inwardly from the dura
mater 42. The inlet ends 16 of the microtubules 12 ex-
tend into the lateral ventricle 30 in a hydra-like fashion.
Likewise, the outermost or discharge end of the micro-
tubules 12 extend hydra-like in the subarachnoid space
38.
It will be appreciated the positioning of the catheter
10 as shown in FIG. 6 does not require any pressure
regulating valves. Such valves are used with conven-
tional catheters that return the cerebrospinal fluid to the
heart or peritonal cavity. Also, this procedure returns
the cerebrospinal fluid to its site of normal absorption in
the subarachnoid space 38.
The large number of inlet apertures 18 formed by the
perforations reduces the tendency for a shunt to draw in
and trap debris or tissue which would then flow or
cause flow obstruction. Also, this combination of ex-
tremely small apertures in the lateral surfaces of the
microtubules together with the fluoropolymer material
of the microtubules reduces the mechanical attachment
of tissue and aids revisions if needed. The small diame-
ter of the perforations 18 reduces the probability of
cerebrospinal fluid flow blockage caused by localized
collapse of the ventricle.
While the preferred embodiment of the invention has
been described it will be appreciated that various struc-
tural modifications and procedural changes may be
made without departing from the spirit of the invention
or the scope of the subjoined claims. More particularly,
it is contemplated that both the material and the geome-
try of the sputter mask mesh 28 can be varied. This, in
turn, changes the positioning as well as the configura-
tion of the perforations 18 in the microtubules 12. It is
also contemplated that while the microtubules 12 are
shown mounted on a mandrel 24 in a substantially paral-
lel juxtaposition, as shown in both FIGS. 2 and 3, other
mounting arrangements may be relied on. More particu-
larly, the microtubules 12 may be wrapped on the man-
drel 24 in a spiral mounting. It is further contemplated
that the microtubules 12 shown in FIG. 3 may be
twisted and held in a twisted position during ion sput-
tering. Subsequent to the perforations 18 being formed
the twisting forces are removed so that the perforations
then have a general spiral configuration about the walls
of the microtubules 12.
What is claimed is:
1. In a ventricular catheter for controlling the condi-
tion of hydrocephalus by relieving the excessive cere-
brospinal fluid pressure, the improvement comprising
a plurality of pliable microtubular members for con-
ducting cerebrospinal fluid from the cerebral ven-
4,377,169
tricle to selected areas of the human body, each of
said irHcrotubular members having a plurality of
microscopic perforations having diameters be-
tween about 14 microns and about 150 microns in a
density of approximately 1100 perforations per 20
jim per centimeter of microtube in a portion of the
walls thereof adjacent to at least one end of said
member.
2. A ventricular catheter as claimed in claim 1
wherein the microtubular members are of a fluoropoly-
mer material.
3. A ventricular catheter as claimed in claim 2
wherein the microtubular members are of a fluoropoly-
mer material selected from the group consisting essen-
tially of polytetrafluoroethylene and fluoroethylene
propylene.
4. A ventricular catheter as claimed in claim 1 includ-
ing a tubular sheath member for enclosing said microtu-
10
15
bular members with said perforated portions of said
microtubular members extending from one end of said
sheath.
5. A ventricular catheter as claimed in claim 4
wherein the tubular sheath member is of a silicone rub-
ber material.
6. A ventricular catheter as claimed in claim 5
wherein the tubular sheath member has a diameter of
about 0.015 m.
7. A ventricular catheter as claimed in claim 6
wherein the microtubular members have diameters of
about 0.44 mm.
8. A ventricular catheter as claimed in claim 7
wherein the one end adjacent to the perforations in each
of the microtubular members has an opening therein
that is substantially greater than each of said perfora-
tions.
20
25
30
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Ion beam sputter-etched ventricular catheter for hydrocephalus shunt

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