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FIELD OF THE INVENTION
This invention relates to an improved implantable percutaneous device, in
particular to an improved capping and valving system for a low profile
percutaneous device which prevents foreign material and microorganisms
from entering the body through the lumen of the conduits of such devices.
BACKGROUND OF THE INVENTION
A percutaneous implant is an object, foreign to the body, that has been
placed through the skin to allow a port of entry to inner body spaces and
structures. Temporary percutaneous access is required for a wide variety
of procedures such as intra-venous fluid administration and hemodialysis.
A number of these procedures also require chronic access. Specific
examples of applications which benefit from a chronic percutaneous port
include hemodialysis access, peritoneal dialysis access, power supply
leads and fluid connections for artificial organs, charging for cardiac
pacemakers, neuroelectric stimulation of nerves and/or muscles, artificial
stimulation and monitoring in various brain implants.
Acute percutaneous access is routinely accomplished with devices
constructed of silicone, polypropylene and polyurethane. These devices
serve as a mechanism by which to gain blood access, wound drainage and
many other applications. The chronic use of such devices, however,
commonly results in infection and/or encapsulation of the device by the
epidermis. Past attempts to overcome these problems have included a
variety of devices constructed of various materials and have included both
rigid and flexible devices.
Percutaneous implant devices are designed to prevent bacteria from entering
the body through skin exit site areas. The standard design for
percutaneous implants consists of a central conduit surrounded by an
attached flange. The flange can be a rigid or flexible disk that is
covered with a flexible biocompatible material such as expanded
polytetrafluoroethylene (PTFE), polyester and polyamide velours,
polyurethane, polypropylene and polyethylene. These biocompatible
materials are normally porous in structure to allow for sufficient
connective tissue ingrowth and anchorage. Epithelium is directed downward
allowing for contact epithelium inhibition and forms a bacterial seal with
connective tissue preventing the evagination and extrusion of the
percutaneous implant device. Connective tissue ingrowth and
vascularization are designed to form a barrier at the skin exit site to
prevent foreign material and microorganisms from entering the body.
There is a need for an easily handled and effective system for preventing
foreign material and microorganisms from entering through the lumen, a
major problem when the exchange of fluids into or out of the body is
required. Most percutaneous implants contain a central conduit of a
biocompatible material that is attached to the flange ingrowth segment of
the device. The common conduit materials are polydimethylsiloxane (silcone
rubber), polyurethane, polyethylene, polypropylene,
polytetrafluoroethylene, polycarbonate, titanium and carbon. This conduit
extends through the body and is capped by a variety of means. When filling
the conduit with materials such as wires, fibers and various leads,
contamination is not a great problem because these materials can be sealed
or adhered solidly into the lumen of the conduit. This solid barrier in
the lumen allows for a variety of attachment mechanisms such as magnets,
screw on devices and friction fit apparatus to be utilized as connection
and disconnection systems. Because these conduits are not open conduits,
special connectors that act as a mechanical fuse and separate at the
interface without damage to the interface have been developed as set forth
in U.S. Pat. No. 4,004,298.
Openings through the flange ingrowth segment are provided to allow for the
passage of a variety of tubings, catheters and conduits. These conduits
are permanently attached to the flange portion by molding, sealing or
adhesion or they can be temporarily placed through the flange portion as
shown in U.S. Pat. No. 3,402,710. Through the lumen of these various
conduits, fluids are allowed to flow in and out of the body. At the
exterior, proximal end of these conduits, outside the body, standard luer
lock fittings and adapters can be secured. The potential for an exposed
lumen in the conduit can occur anytime a connection or disconnection is
made with an additional fluid line, such as an intravenous line. Any
breaks or holes in any part of the system also lead to an exposed lumen.
Any time the conduit is opened in any manner, the introduction of
infection may result, leading to septicemea, emboli, backbleeding or
backflow of other vital body fluids (Coppa, G. F., Gouge, T. H., and
Hofstetter, S. R.: Air Embolism: A Lethal but Preventable Complication of
Subclavian Vein Catheterization. J. Parenteral & Enternal Nutrition
5(2):166-168, Mar/Apr 1981).
Skin interface disruption can also result when conduits protrude from the
body. The forces disrupting the interface are normally caused by actions
such as twisting, tugging and pulling while handling the external portion
of the conduit during connection and disconnection (Von Recum, A. F., and
Park, J. B.: Permanent Percutaneous Devices. CPC Critical Reviews in
Bioengineering 5(1):37-77, 1981). Without proper dressings and taping of
the conduit down to the skin, tightness of clothing can also irritate the
interface site presenting additional trauma (Erlich, L. F., and Powell, S.
L.: Care of the patient with a Gore-Tex Peritoneal Dialysis Catheter.
Dialysis & Transplantation 12(8):572-577, Aug. 1983).
Because of the need to physically seal an open conduit during connections
and disconnections, mechanical damage can result, necessitating repairs or
the eventual removal of the device. The same type of damage that occurs to
standard catheters can occur to any type of conduit placed through a
percutaneous device because of the necessity to physically seal the lumen
during connections and disconnections (Gulley, R. M., Hawk, N.: Rupture of
Indwelling Venous Catheters. J Parenteral & Enteral Nutrition
7(2):184-185, Mar/Apr, 1983).
Prior art has disclosed a percutaneous implant device for drug injection
with a normally closed value in a passageway, for administration of
medication, e.g. U.S. Pat. No. 3,783,868 and 4,321,914. However, the known
prior art does not address the complications of skin exit disruptions due
to forces applied to the exterior portions of the conduit during
connections and disconnections.
The solution to these problems is found in the improved implant device of
this invention that utilizes design advantages, the physical properties of
the materials used and a unique handling system.
SUMMARY OF THE INVENTION
A percutaneous implant device to provide a port of entry into the body is
provided comprising a nonporous, biocompatible conduit having an upper
inlet opening and a lower attached flange, the flange having a top with a
continuously curved perimeter and a continuously curved side wall which
tapers to a bottom wall having a continuously curved perimeter of larger
diameter than said top, and having a central opening therethrough
extending from said top through said flange to said bottom wall, said
conduit extending from the top of the attached flange and having an angle
bend just above said flange which, in use, extends at an angle to the
skin, from the bend location to the conduit inlet.
The preferred device comprises:
(A) a nonporous, biocompatible conduit having an attached flange, the
flange having a top with a continuously curved perimeter and a
continuously curved side wall which tapers to a bottom wall having a
continuously curved perimeter of larger diameter than said top, and a
central opening therethrough extending from the top through the flange to
the bottom wall,
(B) the conduit extending from the top of the flange first necking inwardly
and then flaring outwardly forming an hourglass configuration,
(C) the conduit having a substantially right angle bend above the hourglass
configuration which, in use, extends substantially parallel to the skin,
from the bend portion to the conduit inlet,
(D) the conduit, within a part of the hourglass portion, having an inside
diameter which is larger than the inside diameter of the remainder of the
conduit, thereby providing a decreased conduit wall thickness at the
hourglass configuration,
(E) an upper skirt and a bottom skirt formed of expanded, porous
polytetrafluoroethylene having nodes and fibrils, with average fibril
length greater than or about 60 microns to permit the in-growth of
epidermal and connective tissue,
(i) the upper skirt attached to the side wall of the flange and extending
from the perimeter of the bottom wall to just below the minimum diameter
of the hourglass configuration, such that, in use, the upper skirt is
place subcutaneously and,
(ii) the lower skirt being in laminar contact with the bottom wall and
connected to the upper skirt adjacent the perimeter of the bottom wall.
The porous, expanded polytetrafluoroethylene preferably has average fibril
length greater than about 60 microns, ethanol bubble points less than
about 2.0 psi, ethanol mean flow pressure less than about 10 psi, and
density less than about 1 gram/cc. Most preferably, the expanded PTFE has
average fibril length greater than about 100 microns, ethanol bubble point
less than about 0.75 psi, ethanol mean flow pressure less than 3.0 psi and
density in the range of about 0.3 to about 1.0 grams/cc. Removable cap
means and removable blunt insertion needle assembly means are provided.
Attachment means for attaching the cap and blunt needle assembly comprise
a male two start acme thread about the conduit. This thread engages the
female two start acme thread port of the cover cap or the blunt insertion
needle assembly means. A mechanical connecting apparatus is incorporated
in the central opening of the flange providing connecting means between
the bottom of the flange and an internal conduit. The conduit and flange
are preferably formed of medical grade, biocompatible polydimethylsiloxane
elastomer. A self-sealing face valve is located at the opening of the
conduit.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a side elevation of the percutaneous implant device of this
invention.
FIG. 2 is a front elevation of the device.
FIG. 3 is a bottom plan view of the device.
FIG. 4 is a cross-sectional view of the device implanted in a body taken
along line 4--4 of FIG. 2.
FIG. 4A shows a preferred design of a self-sealing face valve inserted into
the conduit inlet of the device, in cross-section.
FIG. 4B is a front elevation of the valve shown in FIG. 4A and FIG. 4C is a
side elevation thereof.
FIG. 5 is a top plan view of the connector used with this device.
FIG. 6 is an elevational view of an alternate connector, partly in
cross-section connected in-line to an internal conduit.
FIG. 7 is a side elevation of a blunt needle assembly to be used with the
device of the invention.
FIG. 8 is a front elevation of the blunt needle assembly.
FIG. 9 is a cross-sectional view of the blunt needle assembly taken along
the line 9--9 of FIG. 7.
FIG. 10 is a side elevation, partly in corss-section, of a protective cover
for the device of this invention.
FIG. 11 shows a percutaneous implant device known in the prior art.
FIG. 12 shows schematically the apparatus used in conducting the bacterial
challenge testing for the catheter of the invention.
FIG. 13 is a schematic view, many times magnified, of the microstructure of
expanded polytetrafluoroethylene.
DETAILED DESCRIPTION OF THE INVENTION AND PREFERRED EMBODIMENTS WITH
REFERENCE TO THE DRAWINGS
A percutaneous implant device is provided which is stable, biocompatible,
substantially infection-free and provides a long-term port of entry into
the body, the device having an easy-to-use, effective,
contamination-resistant capping and valving system for the exchange of
fluids into and out of the body. The device comprises a nonporous
bicompatible conduit having an attached flange, the flange having a top
and bottom. In the preferred embodiment, at the top of the flange, where
the flange and conduit connect, the conduit emerges from the flange, necks
inwardly and then flares outwardly forming an hourglass configuration.
Above this neck the conduit forms substantially a right-angle bend, the
conduit then extending substantially parallel to the skin. The device is
implanted in the body such that the flange is below the surface of the
skin. The flange preferably is covered with a porous, biologically inert
material which permits growth of connective tissue and vascularization.
Within the neck portion of the device, the inside diameter of the conduit
is increased resulting in a decrease of the conduit wall thickness in the
neck region creating a point of flexion which acts as a cushion to absorb
forces that could otherwise disrupt the skin/device interface. By reason
of the bend in the conduit, the conduit can be grasped and held firmly
while pressure is applied parallel to the skin surface to insert a needle
into or apply a cover cap to the conduit. Removable protective cap means
and blunt insertion needle assembly means are provided, as well as
suitable valving and connector means, providing a connection between the
bottom of the flange and any internal conduit.
A percutaneous device 10 of the present invention is shown in FIG. 1 and
comprises biocompatible conduit 12 with an attached flange 14. At the top
of the flange, where the flange and conduit connect, the conduit 12
emerges from the flange and the exterior of the conduit flares inward and
then outward forming an hourglass or neck configuration 16. The convex
section of the conduit 18, FIG. 1, is termed the collar portion of the
device.
Above the collar 18, on the exterior side of the flange, the conduit bends
at an angle, preferably in a direction that will run substantially
parallel to the skin externally.
The flange is covered with a porous biologically inert material comprised
of expanded polytetrafluoroethylene (PTFE). Expanded PTFE has a
microstructure which consists of a three-dimensional matrix of nodes
connected by fibrils. This porous microstructure allows for the ingrowth
of connective tissue and vascularization. The top and bottom of the flange
are covered with this porous skirt material 17, 19. The top skirt 17 is
adhered to the top of the flange from the upper portion where the conduit
and flange meet, past the outer diameter of the flange. The bottom skirt
19 is adhered to the bottom of the flange, also extending beyond the
maximum diameter of the flange. The bottom cover 19 and top skirt 17
materials are bonded together beyond the outer diameter of the flange in
the line 21 formed between the covers. Epidermal cells may extend to and
attach to connective tissue within the porous PTFE cover material.
It is believed that other porous biocompatible materials could be used. The
porous material must allow rapid ingrowth of connective tissue to inhibit
the apical migration of epithelium along the surface of the material.
Preferably the porous material is soft and flexible. Suitable
biocompatible materials which could be made porous include, but are not
limited to, silicones, polyurethanes, polyethylenes, polysulfones,
polyacrylics, polycarboxylates, polyesters, polypropylenes,
poly(hydroxyethylmethacrylates), and perfluorinated polymers such as
fluorinated ethylene propylene, as well as polytetrafluoroethylene.
The above-mentioned materials may be made porous by techniques known to
those skilled in the art which will render the materials capable of
supporting connective tissue ingrowth while preventing apical migration of
epithelium. Such tecniques include, but are not limited to, sintering
carefully controlled sizes of polymer beads; combining the materials with
a partially resorbable implant that would resorb or could be resorbed, in
vivo or in vitro, to leave a porous surface; weaving or knitting fibers
together to form a fabric-like material; or using a foaming agent during
processing to cause bubbles to form and leave pores as the material
hardens.
The porous material may be treated or filled with biologically active
substances such as sntibiotics, fibrin, thrombin, and collagen. These
substances may enhance connective tissue formation within the porous
material and inhibit infection during healing.
The porous material of the preferred embodiment, as stated, is expanded
polytetrafluoroethylene (expanded PTFE). Expanded PTFE is an extremely
inert and biocompatible material with a history of medical implant use.
U.S. Pat. Nos. 3,953,566 and 4,187,390, the disclosures of which are
incorporated herein by reference, teach methods for producing expanded
PTFE and characterizing its porous microstructure. The porous structure of
expanded PTFE is further schematically illustrated in FIG. 13. The
microstructure of expanded PTFE is a three-dimensional matrix of nodes 97,
connected by fibrils 98. The pore size of expanded PTFE can be
characterized by determining the bubble point and the mean flow pressure
of the material. Bubble point and mean flow pressure are measured
according to the American Society for Testing and Materials Standard
F316-80, using ethanol.
The density of expanded PTFE determines the amount of void space in the
material which may become ingrown with connective tissue. The density of
expanded PTFE is the ratio of the mass of a given sample of expanded PTFE
to its volume.
The fibril length of expanded PTFE is defined herein as the average of ten
measurements of distances between nodes connected by fibrils in the
direction of expansion. In order to measure the average fibril length of
expanded PTFE, two parallel lines are drawn across a photomicrograph of
about 40 to 50 times magnification of the surface of the material so as to
divide the photgraph into three equal areas. If the material has been
uniaxially expanded, these lines are drawn in the direction of expansion,
i.e. direction of longitudinal orientation of fibrils as shown in FIG. 13.
Measuring from left to right, five measurements of fibril length are made
along the top line in the photograph beginning with the first node to
intersect the line near the left edge of the photograph and continuing
with consecutive nodes intersecting the line. Five more measurements are
made along the other line from right to left beginning with the first node
to intersect the line on the right hand side of the photograph. If the
material is expanded in more than one direction, the lines are drawn and
fibril lengths measured as above, except when a node is not attached by
fibrils to a node intersecting the drawn line. In that case, the fibril
length from the node to a node which creates the least angle with the
drawn line is measured along the fibril's axial orientation. The ten
measurements obtained by this method are then averaged to obtain the
average fibril length of the material.
Materials with average fibril lengths greater than about 60 microns,
preferably greater than about 100 microns, ethanol bubble points of less
than about 2.0 psi, preferably less than about 0.75 psi, ethanol mean flow
pressure less than about 10 psi, preferably less than about 3.0 psi, and
densities less than about 1 gram/cc and preferably about 0.3 to about 0.1
gram/cc enhance connective tissue ingrowth and are therefore most
preferred for use in the present invention.
When expanded PTFE is used as the porous material, a number of nodes 97 may
pass through the wall thickness of the expanded PTFE, as illustrated in
FIG, 13, which may provide channels for tissue ingrowth and a wall
resistant to crushing. In the preferred embodiments, an expanded PTFE skin
interface with a wall thickness of approximately 1 mm is used. It should
be understood that one side may be laminated which will tend to close the
pores not allowing for tissue ingrowth. This portion is not intended for
tissue ingrowth and will not pass ethanol bubble point testing described
above.
The device of the present invention provides for the central conduit 12 to
contain a capping and valving system 24 which is an integral part of the
device. The preferred material for the conduit is medical grade,
biocompatible and inert polydimethylsiloxane. The conduit emerges from the
epidermis perpendicular to the skin surface. In the section of conduit
that emerges from the epidermis perpendicular to the skin surface,
referred to as the neck 16, a point of flexion is made at the minimum
diameter. Increasing the inner diameter of the conduit by several
thousandths of an inch inside the neck 16 results in reducing the wall
thickness by several thousandths of an inch. The reduction in wall
thickness over a length of approximately 0.100 inches* along the conduit
creates this point of flexion. This point of flexion is preferably created
approximately 0.050 inches from the point where the external portion of
the conduit 12 connects with the flange ingrowth segment of the device.
This flex point serves as a cushion to absorb and redirect forces that
could otherwise disrupt the skin/device interface. Following the conduit
exteriorly past the said flex point, a bend in the conduit positions the
conduit so that it runs parallel to the skin surface for a distance of an
inch. The bend in the conduit absorbs some or all of the forces that are
generated when pressure is applied. Forces are normally required to attach
various apparatus to low profile implant devices which results in the
disruption of the living tissue from the ingrowth segment of the device.
By positioning a permanent bend in the conduit approximately 0.230 inches
from the point of flexion, the conduit can be grasped and held firm, while
pressure is applied parallel to the skin to insert a needle or apply the
cover cap to the external end of the conduit. Forces applied to the
exterior portion of the conduit will be absorbed or redirected by the flex
point allowing the conduit to bend, due to weakness of the wall structure
created by this point of flexion. Preferably the forces that would
otherwise disrupt the flange living tissue interface will be absorbed by
the flexible conduit and flex points. A biocompatible thermoplastic
polymer mounting ring 22 is permanently adhered to the external end of the
conduit 12. This rigid material containing an external male two start acme
thread 34 which allows for the end of the conduit to be connected to a
removable protective cap and a removable blunt insertion needle assembly.
*All dimensions given are exemplary and/or preferred.
Connector 42 shown in FIG. 1 serves to connect the implant device 10 to an
internal body conduit 44.
FIG. 2, in a front elevation, shows the device 10 and face valve 24 having
slit 28 inserted into the exterior end of the device. Slit 28 allows
insertion of blunt needle apparatus. Also shown in FIG. 2 are the flange
covers 17 and 19, bonded at common area of contact 21, and connector 42.
FIG. 3 shows a bottom plan view of the implant device 10 whose bottom is
covered with the expanded, porous PTFE cover 19 connected via connector 42
to internal body conduit 44.
FIG. 4 shows a corss-sectional view of the assembly of this invention,
implanted in a body, taken substantially along the line 4--4 of FIG. 2.
The device is placed in the body so the portion of the conduit called the
neck 16 is placed through the skin comprising the epidermis, 52, the
dermis, 54, and subcutaneous tissue, 56, in such a manner as to leave the
flange below the surface of the skin. The outer diameter of the neck
portion of the conduit provides a continuously curving geometry which
encourages and directs epidermal cells to grow in a direction toward the
flange.
A flexible, normally closed, convex, cleanable face valve 24 is attached at
the external end of the conduit. This valve is preferably a selfsealing
slit valve, comprised of a medically acceptable elastomeric polymer. This
valve is physically opened by means of a blunt insertion needle. Upon
attachment of the insertion needle assembly 40 to the exterior of the
device, the convex cleanable face valve is physically opened. In the event
the insertion needle assembly 40 is removed, the face valve will close and
seal. This valving system eliminates the need for greater lengths of
external conduits and tubing. Elimination of dangling conduits reduces the
potential number of incidences of skin exit disruptions by removing
unwieldly, cumbersome and often heavy capping and valving mechanisms which
are at the ends of these conduits.
A preferred valve design is illustrated in FIGS. 4A and 4B. As the infusion
needle penetrates through the slit valve shown, it passes through a
concentric type seal which snuggly captures the needle except for the tip.
This seal prevents leakage around the needle while in place through the
slit. As shown in FIGS. 4B and 4C, this valve is molded with additional
material 25 above and below slit 28. When inserted into the mounting ring
22, the compression of the face valve by the mounting ring provides a
preferred stress on the slit in the valve as a result of the additional
material 25, resulting in preferred forces directed at keeping the slit 28
closed.
As shown in FIG. 4, at the bottom of the flange segment of the device, the
lumen of the conduit is designed to allow for the secure insertion of
additional conduit material 42. Preferably, a biocompatible thermoplastic
polymer connector with barbed fittings 45 on each end can be used to
connect additional tubing 44, ingrowth segments or other apparatus. This
thermoplastic connector can be snapped into the device utilizing built-in
silicone O-rings in the device for a secure pressure fit that eliminates
leakage. With this pressurized fit, the connector can swivel to allow
proper placement of the internal conduit during implantation. The
connector 42 can also be securely adhered in place. The connector 42 can
protrude from the device perpendicularly or can have various bends and
angles depending on the appropriate placement of the internal apparatus.
By eliminating the valves in the device and the internal connector, the
passageway of the device can be placed with electrical wires, power supply
units, such as rechargable batteries, and fiber optic strands.
The percutaneous implant device 10 comprises conduit 12 having a collar 18,
a neck portion 16 and a flange portion 14, all preferably made of
silicone. The device is implanted so that the flange is placed under the
skin and the neck and collar of the conduit protrudes through and above
the skin as shown in FIG. 4. The height of the conduit, from the bottom of
the flange including the PTFE cover material 19 to the transition point
where the bend in the conduit begins, is approximately 0.530 inches. The
collar portion of the conduit protrudes through the epidermal layer 52 and
guides the epidermal cells along the neck portion towards the porous PTFE
material 17. The collar has a diameter of about 0.360 inch with a range
from 0.250 inch to 2 inches. The neck portion is the narrowest part of the
conduit, approximately 0.260 inch in diameter. As the neck flares outward
and is directed towards the flange, it reaches a maximum diameter at the
base of approximately 0.306 inch. The conduit is directed inward at this
point over a distance of about 0.035 inch. At the end of this
indentation, the flange begins and the diameter is about 0.266 inch at
this point. The difference in diameters between the neck base and the
start of the flange forms an indentation allowing a snug fit for the
expanded PTFE cover. The flange has a maximum diameter of approximately
0.600 inch.
The lumen 20 of the conduit from the collar to the base of the neck is
about 0.100 inch in diameter, excluding the point of flexion. In the
middle of the neck, a point of flexion 20A is created by increasing the
inner diameter of the conduit to about 0.130 inch for a height of 0.100
inch. This point of flexion starts approximately about 0.050 inch from the
base of the neck and flange. The point of flexion 20A is ideally located
in the middle of the neck.
The implant device 10 has a rigid mounting ring 22, preferably
polycarbonate, which is bonded to the conduit 12. Adhered inside the front
portion of the rigid mounting ring 22 is the cleanable, smooth, convex
face valve 24, preferably silicone. As the blunt needle 26 of the
injection needle assembly 40 is inserted to physically open the
self-sealing slit 28 of the silicone face valve, the injection needle
assembly threads 32 are screwed onto the external mounting ring thread
connections 34 and held. When the face valve 24 is physically opened, the
lumen of the device 20 is exposed. As fluid is introduced and flows
through the lumen of the insertion needle 26, it flows through the side
openings 36 of the blunt needle 26 and into the lumen 20 of the device.
The fluid can flow through the connector 42 into the internal conduit 44
to the desired location.
The rigid mounting ring 22 may be treated by a spray or coating process of
monosiloxane SiO.sub.2 (U.S. Pat. No. 3,986,977). This coated surface of
the ring allows for the bonding of the silicone conduit 12 to the ring by
means of a silicone adhesive.
The mounting ring 22 may be from about 0.100 inch to 1.0 inch long.
Preferably the mounting ring is about 0.60 inch long. The inner diameter
of the ring may be from about 0.10 inch to 0.3 inch, the outer diameter
from about 0.2 inch to 0.5 inch. Preferably the inner diameter is about
0.200 inch, and the outer diameter about 0.312 inch. The external threads
34 on the mounting ring can be from about 0.030 inch to 0.045 inch wide.
Preferably the width of the threads is about 0.038 inch. The length of the
threads cover a distance of about 0.280 inch to 0.310 inch. Preferably the
threads cover a distance of 0.290 inch.
The insertion needle assembly 40 can be made from several different
materials such as polycarbonate, polysulfone, polypropylene, polyamides,
polyurethane, stainless steel, and polyethylene. The inner diameter of the
needle assembly which encompasses the mounting ring may be 0.2 inch to 0.5
inch. Preferably the inner diameters is 0.314 inch to provide a tight,
secure seal while placed over the mounting ring. The outer diameter of
this end can be 0.25 inch to 0.600 inch but preferably is 0.375 inch. The
threads 32 can have a width of 0.030 inch to 0.045 inch. Preferably the
width of the threads are 0.038 inch. The length of the threads should
cover a distance of 0.280 inch to 0.310 inch. Preferably the threads cover
a distance of 0.290 inch. The threads have a depth preferably of 0.0255
inch. The pitch of the threads is preferably 5 threads per inch. At the
end of the needle assembly is a 2 degree friction taper fit for added
security.
The length of the needle can be from about 0.080 inch to 0.380 inch.
Preferably the length of the needle is 0.240 inch. The length of the
needle and valve determines whether the face valve is utilized in a
partially opened mode or a completely opened mode. This affects the
pressure at which fluids are injected. The lumen of the needle can be from
0.005 inch to 0.150 inch. The needle inner diameter is dependent on the
application and the flow requirements. Dialysis would require a different
flow volume than parenteral nutrition therapy. The diameter of the needle
is dependent upon the inner diameter of the needle. Preferably a wall
thickness for the needle should be about 0.015 inch, but can be about
0.010 inch to 0.040 inch.
The inner diameter of the assembly can be from about 0.050 inch to 0.300
inch. Preferably the inner diameter is about 0.170 inch with a 2 degree
taper that will accomodate standard luer lock friction fits. At the end of
the needle assembly is a pair of projecting parts that will fit standard
luer lock female apparatus.
The overall length of the needle assembly can be from about 0.400 inch to
1.50 inch. Preferably the overall length is about 0.750 inch.
The protective cover cap can have an inner diameter of about 0.200 inch to
0.500 inch. Preferably the inner diameter is about 0.314 inch to ensure a
secure fit over the mounting ring. The wall thickness of the protective
cap cover from the concave portion to the edge of the cap can be about
0.005 inch to 0.100 inch with the internal threads 50 being from about
0.030 inch to 0.045 inch. Preferably the wall thickness should be about
0.030 inch, while the thread should be about 0.038 inch wide. The length
of the threads should cover a distance of 0.280 inch to 0.310 inch with a
pitch of 5 threads per inch. Preferably the threads cover a distance of
0.290 inch. Preferably the wall thickness should be about 0.030 inch. The
overall length of the cap can be from about 0.250 inch to 0.750 inch. To
prevent excessive contact with clothing, dressings, etc., it is preferable
to have the length of 0.515 inch which still provides ease of handling
while keeping a low profile. The protective cap cover can be molded,
machined, or fabricated out of such materials as polypropylene,
polycarbonate, polysulfone, polyethylene, polyamides, polyurethane or
stainless steel.
The connector 42 should be made out of biocompatible, nonporous, rigid or
semi-rigid material such as polytetrafluoroethylene, polycarbonate,
polysulfone, polypropylene or polyurethane. The outer diameter can be
0.200 inch to 0.500 inch while the inner diameter can be 0.005 inch to
0.150 inch. The diameters of the connector should coincide with the
diameter of the lumen of the needle to be used to allow for sufficient
flow all through the device. The wall thickness of the connector can be
from about 0.010 inch to 0.200 inch. Preferably the wall thickness is
0.025 inch. The diameter of the barbs 45 on the upper end of the connector
42 range from about 0.100 inch to 0.600 inch. With the diameter of the
barbs being 0.200 inch in diameter, a snap-in fit is ensured in the port.
FIG. 5 shows the bottom view of connector 42 having snap-fit barbs 45 at
both ends.
FIG. 6 shows an alternate connector 42 affixed to a straight-through
internal conduit 44. Connecting barbs 45 are shown for completeness.
FIGS. 7-9 show the insertion needle assembly 40 in detail, including
threads 32 and blunt needle 26.
When the insertion needle assembly 40 is not in use, a protective cap 46
can be attached to the implant device in the same manner as the insertion
needle assembly. This is shown in FIG. 10. The protective cap 46 contains
internal threads 50 which screw onto the external threaded portion 34 of
the mounting ring 22.
Prior art percutaneous implant devices such as that shown in FIG. 11 are
known. This device 60 has a housing or "button" 62 having a collar portion
64, a neck portion 66, a lu | | |
