Implantable access devices

An access port (10) for implantation adapted for providing repeated access to specific tissue within a patient and communicating with the tissue by an internal implanted catheter (52). The access ports according to this invention incorporate an enlarged entrance orifice (13) with a funnel shaped internal cavity that narrows down to a reduced diameter passageway (18). An articulating catheter valve (24) is provided within the passageway which normally prevents the flow of fluids through the valve but which can be penetrated by an external introduced filament (32) such as a catheter. After implantation, an external filament (32) is introduced into the port (10) and guided by the passageway into registry with the catheter valve (24). Continued feeding of the filament (32) causes the filament to pass through the valve (24). Thereafter, with a catheter (32) inserted, therapeutic agents can be infused into the patient, or body fluids can be withdrawn. Alternate embodiments disclose various valve concepts (56) and means for providing a change in direction of an introduced filament inserted through the access device. Additional embodiments disclose the concepts of providing an antimicrobial fluid bath (98) within the device for prevention of infection and various approaches for securely connecting an internal catheter (52) to an access port.

FIELD OF THE INVENTION 
This invention relates to devices for introducing a filament, such as a 
catheter, into a patient for infusing a therapeutic agent to a desired 
site or withdrawing a fluid from the patient. More particularly, the 
invention relates to an access port which is implanted such that no 
portion is transcutaneous. The access port is subcutaneous but designed so 
as to facilitate repeated access by the percutaneous route. 
BACKGROUND AND SUMMARY OF THE INVENTION 
In current human and animal medical practice, there are numerous instances 
where therapeutic agents must be delivered to a specific organ or a tissue 
within the body. An example is the infusion of chemotherapy into a central 
vein on a recurring basis over a lengthy treatment period for widespread 
sites of malignant tumor. Without an access device for intravenous drug 
infusion, multiple vein punctures over a lengthy period would result in 
progressive thrombosis, venous sclerosis, and destruction of small 
diameter peripheral vessels. In other cases, it may be desirable to infuse 
chemotherapy to a localized malignant tumor site. It may be difficult or 
impossible to deliver an agent specifically to such a site on a regular 
repetitive basis without surgically implanting an access system. 
Similarly, repeated arterial access is occasionally needed for injection 
of an X-ray dye or contrast agent into an artery for diagnostic purposes. 
In other situations, there is a need to repetitively remove a body fluid 
for analysis from a remote body site. Finally, sensing and physiological 
measuring devices incorporated into small diameter catheters and small 
diameter optical fibers are increasingly being utilized for monitoring 
body processes and could be more easily implemented through a properly 
designed access device with an adequate internal diameter. 
In prior medical practice, percutaneous catheters have been used to provide 
vascular or organ access for drug therapy or the withdraw of body fluids. 
Although such systems generally performed in a satisfactory manner, 
numerous problems were presented by such therapy approaches, including the 
substantial care requirements of the patients, e.g. dressing changes with 
sterile techniques, a significant rate of infection of the catheter 
because of its transcutaneous position, and a high rate of venous 
thrombosis, particularly if the catheter was located within an extremity 
vein. 
Implantable infusion devices or "ports" have recently become available and 
represent a significant advance over transcutaneous catheters. Presently 
available infusion ports have a number of common fundamental design 
features. The ports themselves comprise a housing which forms a reservoir 
that can be constructed from a variety of plastic or metal materials. A 
surface of the reservoir is enclosed by a high-density, self-sealing 
septum, typically made of silicone rubber. Connected to the port housing 
is an internal catheter which communicates with a vein or other site 
within the patient where the infusion of therapeutic agents is desired. 
Implantation of such devices generally proceeds by making a small 
subcutaneous pocket in an appropriate area of the patient under local 
anesthesia. The internal catheter is tunneled to the desired infusion 
site. When the care provider desires to infuse or remove materials through 
the port, a hypodermic needle is used which pierces the skin over the 
infusion port and is placed into the port. 
Although the presently available implantable infusion ports generally 
operate in a satisfactory manner, they have a number of shortcomings. 
Since these devices rely on a compressed rubber septum for sealing and 
since large diameter needles can seriously damage the septum, there are 
limitations in the diameter of needles which can be used to penetrate the 
septum. Also, the needles are randomly inserted to penetrate the septum, 
producing a cut or puncture wound, partially consuming and destroying the 
septum with each penetration. The diameter limitations severely restrict 
the flow rate of fluids passing through the port. In cases where it is 
desirable to infuse drugs using a flexible external catheter, the catheter 
must be fed through the needle that penetrates the septum. Such catheters 
have an extremely small inside diameter and, therefore, impose severe 
limitations on fluid flow rate. 
During prolonged infusion using a conventional port, the infusion needle is 
taped to the patients skin to hold it in position. Conventional ports do 
not allow the needle to penetrate deeply into the port. Because of this, a 
small displacement of the needle can cause it to be pulled from the port. 
In cases where locally toxic materials are being infused, extravasation of 
such materials can cause local tissue damage which may require corrective 
surgery such as skin grafting or removal of tissue. 
Presently available implantable drug infusion devices also have a 
significant size to provide an acceptable target surface area for the care 
provider who must locate the port and penetrate the septum with a needle. 
The port housing becomes bulky as the septum size increases since 
structure is required to maintain the septum in compression to provide 
self-sealing after the needle is removed. Moreover, presently available 
infusion ports are difficult to clear if thrombosis occurs within the port 
or within the implanted internal catheter since it is difficult, if not 
impossible, to feed a cleaning wire through the penetrating hypodermic 
needle in a manner which will clear the infusion device and the internal 
catheter. Present infusion ports also have a retained volume beneath the 
self-sealing septum which increases the volume of drug which must be 
administered to enable a desired quantity to reach the infusion site. This 
retained volume also poses problems when a care provider desires to 
successively deliver multiple drugs to the same infusion site which are 
incompatible when mixed. Additionally, when it is desired to withdraw 
blood through the port, the retained volume of the prior art infusion 
ports comprises an area where blood clotting can occur, thus interfering 
with future access to the site. And finally, for present infusion ports, 
there is a risk that the care provider attempting to pierce the port 
septum will not properly enter it, leading to the possibility of 
extravasation which can cause significant undesirable consequences as 
mentioned above. 
The present invention relates to a family of implantable access ports which 
provide numerous enhancements over prior art devices. In accordance with 
this invention, an access port is provided which incorporates the 
funnel-shaped entrance orifice which narrows down to a reduced diameter 
passageway. The passageway retains a valve. One characteristic of valves 
used with the present invention is that the valves are not physically 
damaged or destroyed by the passage of a filament through the valve. In 
this regard, the valve can be referred to as being a "non-destructive" 
valve. Another characteristic of the valves intended to be used with the 
present invention is that they are constructed to be repetitively engaged 
by the filament in a predetermined location. Generally , this location is 
the center of the valve. Valves which meets the above criteria are 
referred to as "articulating catheter valves" or "articulating valves", 
such as a multi-element leaflet valve assembly. After the valve, the 
passageway is connected to an implanted internal catheter. 
Several embodiments of this invention are intended to be used by inserting 
an instrument such as a needle, trocar or other introducer through the 
skin into a port entrance orifice which introduces a filament, such as a 
catheter, into the port. While some embodiments of this invention are used 
with blunt introducers, other embodiments of the present invention are 
adapted to be used in conjunction with a sharp hypodermic access needle of 
conventional design which may be used by itself for infusion or fluid 
withdrawal, or with an external catheter having the needle fed through it 
(or vise versa) allowing the catheter to be put in position within the 
access port or fed into the implanted catheter for infusion or withdrawal 
of fluid. The entrance orifice has a hard surface which guides the needle 
to a guide passageway. The reduced diameter guide passageway of the port 
housing can be used to accurately align the access needle and/or catheter 
to strike the articulating valve at a desired area. In this manner, a 
needle can be used to pass through the catheter valve repeatedly without 
damaging the function of the valve. 
According to another group of embodiments of this invention, additional 
features of access ports are described. One area of potential improvement 
for some purposes is the provision of a port designed for implantation in 
a patient's arm which has an access passageway for an inserted needle. The 
body of this port is slightly angled upward to facilitate access. Such an 
angled access port can also feature modifications to the entrance orifice 
to again further enhance the ability to access the implanted port. This 
application further describes a valving concept for an implanted port 
which provides a high degree of resistance to body fluid leakage through 
the port and which further provides a relatively low level of friction 
upon insertion of an external catheter and a relatively higher degree of 
friction upon withdrawal of the catheter. This difference in resistance 
aids both in inserting of the catheter and in maintaining the catheter in 
an inserted condition within the implanted port. 
This specification also describes port design features which are best 
embodied in a port in which the entrance funnel is in a plane generally 
parallel to the mounting base of the port (i.e. the accessing needle 
penetrates perpendicular to the mounting base). One improvement for such 
ports is the provision of a physical feature such as a projecting lug, 
flange or other protuberance which enables the clinician to determine the 
orientation of the implanted port through tactile examination. By knowing 
the port orientation, the needle and introduced filament can often be more 
readily inserted into the port. This series of ports, known as "chest 
wall" ports (named for a preferred usage), also feature a funnel-shaped 
entrance orifice having a progressively changing included angle. The 
orifice starts at its outer periphery with a relatively shallow included 
angle which increases toward the port's center. This progressive change in 
cone angle provides two significant benefits. First, it results in a port 
which has a relatively shallow funnel that reduces the distance between 
the skin surface and the catheter valve which seals around the introduced 
catheter or the filament and which also serves to better orient and hold 
the introduced needle. 
Several of the ports according to this specification also feature means for 
stopping the introduced needle before it reaches the catheter valve but 
which permits the introduced catheter to pass through the catheter valve. 
The access ports in accordance with additional embodiments of this 
invention achieve simplicity in construction and reduce the number of 
components required to provide the necessary fluid seal. In those 
applications where it is desired to access a port using a sharp needle, 
damage to elastomeric sealing elements in prior port designs can occur 
over repeated entries to the port. In accordance with these embodiments, 
the implanted port has an articulating valve mechanism in which the 
accessing needle (or other filament) contacts a hard material, such as a 
metal, to open the valve. Therefore, a durable device is provided which is 
not damaged through long term use. The features of this embodiment are 
achieved through the use of an articulating valve assembly in which a 
sealing element is normally maintained in contact with a valve seat. When 
introducing an external filament, which may be a needle, catheter, wire, 
optical fiber etc., the filament engages the sealing element forcing it 
from engagement with the valve seat. Once fully inserted into the access 
device, features are provided to assure a fluid seal around the introduced 
filament. 
The access ports of this invention are implanted in the same general manner 
as prior art devices. When the care provider desires to infuse a 
therapeutic agent, remove a body fluid, or have vascular access, a 
filament such as a catheter is introduced into the port. The entrance 
orifice guides the introduced catheter or needle into a proper "docking" 
position with the articulating valve. By pushing on the externally 
introduced filament, the filament is forced through the valve, thereby 
providing an open communication pathway for the infusion of therapeutic 
agents, extraction of body fluids, introduction of an optical fiber, 
clearing by a wire, etc. The introduced filament can be fed into the 
internal catheter to any extend desired. In the case of introducing a 
flexible catheter, a guide wire can be inserted into the external catheter 
to increase its rigidity. The convenient access to the port and internal 
catheter enables these elements to be cleared with a clearing wire 
avoiding the problem of permanent impaction as seen in prior art devices. 
In addition, the ability to feed a guide wire into the access port and 
internal catheter of this invention enables the internal catheter to be 
repositioned using a bent or "steerable" guide wire. 
The access ports having an articulating valve of this invention possess the 
advantage that they have a very small reservoir or "dead space", meaning 
that virtually all of the infused fluid is put through to the desired 
infusion site. This invention, therefore, facilitates infusion of 
incompatible materials in a serial fashion since very little of the 
previously infused fluid remains in the device when a subsequent infusion 
is carried out. This invention also facilitates simultaneous infusion of 
incompatible materials by using a multi-lumen catheter inserted through 
the implanted catheter. 
Another aspect of the present invention is a design for an access port 
which is configured such that a line normal to the plane formed by the 
entrance orifice is nearly at a right angle to the exit passageway. The 
port access opening guides an introduced filament toward and into the 
internal catheter. This approach of guiding a catheter to undergo a bend 
through the port can be used with conventional port designs having a 
self-sealing rubber septum. Other aspects of the present invention relate 
to providing a reservoir within an access port for containing an 
antimicrobial (or antibacterial) fluid, offering enhanced protection 
against introduced infection. This invention is further related to various 
means of securely fastening an internal catheter to an access port. 
Additional benefits and advantages of the present invention will become 
apparent to those skilled in the art to which this invention relates from 
the subsequent description of the preferred embodiments and the appended 
claims, taken in conjunction with the accompanying drawings.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
An access port in accordance with a first embodiment of this invention is 
shown in FIG. 1 and is generally designated there by reference number 10. 
Access port 10 generally comprises housing 12 defining an entrance orifice 
14, an inside cavity 13 which funnels down to base 20, with an exit 
orifice 16, and an elongated passageway 18 extending between the external 
orifice base, and exit orifice 16. In the embodiment shown, access port 
housing 12 is rotationally symmetrical about a central longitudinal axis 
passing through passageway 18 and an exit orifice 16, with which it is 
concentric. As is evident from FIG. 1, the conical entrance orifice 14 has 
a circular perimeter and has a diameter which is preferably several times 
greater than the internal diameter of passageway 18 (i.e. an area 
difference of four times or more). The entire housing 12 can be formed in 
one piece from numerous polymeric materials or metals which are compatible 
with human or animal implantation. 
Positioned within passageway 18, substantially adjacent to the entrance 
orifice 14, is an articulating valve assembly. The valve normally remains 
closed and provides resistance to the flow of fluids through the 
passageway. However, the valve will permit a filament to pass through it 
and communicate with an internal catheter as further discussed below. The 
valve is of a type which is not destroyed or physically damaged by the 
passage of the filament through it. Another characteristic of the 
articulating valve used in this and other embodiments is that the valve is 
designed for repetitive engagement by the filament in a predetermined 
location. 
One such articulating valve is a leaflet valve assembly 24, which is also 
shown in an exploded fashion in FIG. 4. Leaflet valve assembly 24 is 
comprised of one or more thin elastic disks 26 made, for example, from 
silicone rubber having one or more radial slits 28 cut through them. In 
development of the access port 10 of this invention, Applicants have found 
that a preferred disk 26, providing the desired characteristics for the 
valve assembly 24, is made from surgical silicone rubber and exhibits a 
hardness number of 27, Shore A, and has a thickness of 0.040 inches. 
In the embodiment shown in FIGS. 1 and 4, two disks 26 are provided, each 
having two slits with a right angle between them so that each defines four 
leaves 30. The disks 26 are oriented and stacked against one another so 
that slits 28 of both the disks are angularly misaligned. This 
misalignment is intentionally provided to enhance the sealing 
characteristics of valve assembly 24 when it is in its normal closed 
position, as shown in FIG. 4. Numerous other configurations for valve disk 
26 can be provided, such as those incorporating any number of slits and 
thus having various numbers of leaves. 
The embodiment of access port 10 shown in FIG. 1 includes an optional thin 
rubber septum 31 which acts to shield entrance orifice 14. When a foreign 
object is implanted in a human, the body often develops fibrous tissue 
around the object. If an exposed concave pocket is present, such as an 
open entrance orifice 14, the pocket could possibly become filled with 
such fibrous tissue. The development of this tissue, should such occur in 
a patient, might restrict access into the port, and potentially could 
interfere with the catheter valve function. Therefore, septum 31 provided 
which is pre-slit at 34 to allow the introduced external filament to 
easily penetrate the septum. Septum 31 does not, however, provide a 
fluid-tight barrier as in prior art access port which have self-sealing 
characteristics and is easily penetrated by an accessing instrument. The 
provision of septum 31 prevents tissue growth inside the housing cavity 
and also enables the region of housing between entrance orifice 14 and 
leaflet valve assembly 24 to act as a reservoir for the retention of an 
antimicrobial fluid which aids in preventing the invasion of infectious 
agents during the use of access port 10. 
In use, access port 10 is surgically positioned subcutaneously within the 
patient and mounted to suitable support tissue using conventional mounting 
techniques including sutures or surgical staples. While it is believed 
that the invention will be mostly readily mounted using fasteners such as 
sutures and staples, other subcutaneous mounting methods, specifically 
lacking fasteners, could also be employed. Internal catheter 52 is 
tunneled to the desired site in the body. When access is desired for the 
access of therapeutic agents, for the sampling of body fluids or for the 
introduction of physiological sensing elements (electrical or optical 
transducers, etc), a flexible external catheter 32 (or other filament) is 
introduced into access port 10, as shown in FIG. 1. Insertion of external 
catheter 32 can be facilitate using skin punch 36 as shown in FIG. 2. Skin 
punch 36 includes a pointed flat blade 38 having a width sufficient to 
make a desired length of an incision 40 shown in FIG. 3. Skin punch 36 
includes a radially extending flange 42 which limits the depth of the 
incision 40. Tab 44 provides a convenient means for holding and using skin 
punch 36. Once external catheter 32 is introduced through stab wound 40, 
it passes into entrance orifice 14 and is guided by the funnel shaped 
configuration of the housing cavity into orientation with leaflet valve 
assembly 24. Continued insertion of external catheter 32 causes the 
external catheter to penetrate leaflet valve assembly 24, causing 
deflection (i.e. "articulation") of valve leaves 30. 
In cases where external catheters 32 are used which are quite flexible, it 
is necessary to provide localized stiffening of the introduced catheter to 
facilitate its introduction through the stab wound and into the proper 
docking position with leaflet valve assembly 24. For such cases, a 
semi-rigid guide wire or obturator 46 having a blunt end 48 can be used 
which is inserted through the internal passageway 50 of catheter 32. 
Leaflet valve assembly 24 is relatively insensitive to the use of various 
diameters of external catheter 32, thus providing flexibility for the care 
provider. Furthermore, the characteristics of leaflet valve assembly 24 
are such that once external catheter 32 is inserted through the valve, the 
valve does not exert a large radially inward compressive force on the 
catheter, thus preventing collapsing of the catheter which would seal off 
internal passageway 50. However, it does provide sufficient friction on 
the external catheter to stabilize its position. 
FIG. 5 illustrates a cup-type articulating valve generally designated by 
reference number 56. Valve 56 is another articulating type valve which can 
be used as a replacement for leaflet valve assembly 24 shown in FIG. 1. 
For this embodiment, a valve passageway 58 is formed which has a generally 
conically shaped exit nipple 60. A cup shaped closure valve 62 is provided 
which is supported in cantilever fashion by arm 64 which normally biases 
the cup closure valve into sealing engagement with exit nipple 60, as 
shown in FIG. 6. FIG. 7 illustrates valve 56 when external catheter 32, 
reinforced with obturator 46 is initially penetrating valve passageway 58. 
During this process, external catheter 32 pushes cup closure valve 62 out 
of sealing engagement with valve nipple 60. FIG. 8 illustrates the 
orientation of the elements of cup closure valve 56 once external catheter 
32 is fully introduced into the access port. 
FIG. 9 illustrates another embodiment for an articulating valve in the form 
of a ball-and-seal valve, generally designated by reference number 68. 
Ball-and-seat valve 68 defines a conical ball seat 70 with ball closure 
valve 72 which is normally biased into sealing engagement with the ball 
seat by arm 74. Operation of ball-and-seat valve 68 is similar to the 
operation of cup valve 56 previously described. In both cases, external 
catheter 32 (or another filament), which may be stiffened by an obturator 
46, physically unseats the valve element to permit passage of the external 
catheter. 
Although the leaflet, cup, and ball-in-socket catheter valves described 
previously differ in their construction, each can be described as an 
"articulating" valve in that the introduced filament is accurately guided 
into an insertion area for the valve and deflects an element to the valve 
in a predictable and repeatable manner to permit passage of a catheter or 
other filament. These valve types are further distinguishable over the 
previously used septums in that they are not randomly punctured and 
physically damaged with each insertion of the filament. It is submitted 
that there are numerous additional articulating, non-destructive valve 
designs which achieve the desired characteristics and which could be 
utilized in the embodiments of the present invention. The application 
should therefore not be interpreted as being limited to the specific 
embodiments disclosed herein. 
FIG. 12 illustrates access port 10 described previously and shows that once 
external catheter 32 penetrates leaflet valve assembly 24 (or any other 
type of articulating valve used), the external catheter can be positioned 
at any desired point along internal catheter 52. FIG. 13 is a view similar 
to FIG. 12 but shows that external catheter 32 can be fed through access 
port 10 so that its terminal end extends beyond that of internal catheter 
52. This feature allows access port 10 to be readily adapted for 
angiography and angioplasty procedures. 
Now with reference to FIGS. 14 and 15, a second embodiment of an access 
port according to this invention is shown which is generally designated by 
reference number 80. Access port 80 differs principally from access port 
10 in that the internal cavity 81 of housing 82 is in the shape of a 
curved, bent or twisted funnel or horn such that a line normal to the 
plane defined by entrance orifice 84 is generally at a right angle to the 
longitudinal central axis of exit passageway 86. Like the first 
embodiment, access port 80 employs an articulating valve, such as a 
leaflet valve assembly 24 as previously described. 
Access port 80 has a smooth inside surface 81 which is shaped to have a 
decreasing cross sectional area from the perimeter of entrance orifice 84 
to exit passageway 86 for guiding external catheter 32 into registry with 
the exit passageway. The configuration of access port 80 is desirable 
where a large target area is needed which is generally parallel to the 
surface of the patient's skin overlying the device. In all other respects, 
access port 60 is constructed and used in the manner consistent with that 
of access port 10 previously described. FIG. 15 provides an illustration 
of access port 80 in use for infusing a patient. Port 80 is shown fastened 
to support tissue 88 by sutures 90 below skin 92 of the patient. As in the 
prior embodiments, the port could be subcutaneously mounted by methods not 
requiring or using fasteners. 
FIG. 16 is a partial sectional view of an access port 94 according to a 
third embodiment of this invention. This embodiment differs from those 
described previously in that a pair of leaflet valve assemblies 24 is 
provided along internal passageway 18 to define an enclosed internal 
cavity 98. Internal reservoir or cavity 98 is provided so that an 
antimicrobial solution 102 can be retained as a means of inhibiting the 
introduction of infectious agents into the patient through the process of 
infusion. 
FIG. 17 illustrates an access port in accordance with a fourth embodiment 
of this invention which is designated by reference number 106. Like the 
second embodiment shown in FIG. 14, access port housing 108 has an 
internal cavity 109 which causes an external catheter or other filament to 
undergo a right angle bend as it is fed into the device. However, access 
port 106 does not incorporate an articulating valve, but rather uses the 
conventional approach of using a compressed rubber septum 110. In use of 
this embodiment, a hypodermic needle 112 penetrates septum 110 and a small 
diameter catheter 114 is fed through needle 112. As discussed previously 
in connection with FIG. 14, the internal surface configuration of housing 
cavity 109 causes catheter 114 to be guided into and through passageway 
116, and if desired, into the attached internal catheter (not shown). This 
embodiment also provides the advantages that a guide wire can be fed 
through needle 112 to clear thrombosis or other obstructions occurring 
within the device or in the attached internal catheter. 
FIGS. 18 and 19 illustrate a fifth embodiment of an access port 120 
according to this invention which may have an articulating valve as 
described previously, or may employ a compressed rubber septum like that 
of the embodiment shown in FIG. 17. These figures, however, illustrate 
that entrance opening 122 can form a generally elliptical configuration, 
as opposed to the previously seen circular configuration, such that the 
target area for the access port has an increased or greatest area when 
entering the device from a direction between alignment with the exit 
passageway 126, or at right angle to exit passageway. In other words, a 
line normal to entrance opening 122 forms an obtuse angle to the axis of 
exit passageway 126. Like the prior embodiments, housing 124 has a smooth 
internal surface which is shaped to include a guide lip 128 which aids in 
introducing an external catheter into passageway 126. 
FIGS. 20 through 23 illustrate various means for attaching an internal 
catheter 52 to an access port. For the embodiment of FIG. 20, the access 
port features an exit end 130 defining an annular gap 132 formed between 
an outer tubular portion 134 of the exit outlet 134 and an inner tubular 
portion 136. Internal catheter 52 is slid onto inner tube 136 and into 
annular gap 132. Sealing means such as a gasket or 0-ring 138 can be 
provided to enhance the integrating of the fluid tight connection. 
Compression ring 140 can be used which is slid onto the connection as 
shown in FIG. 20 to exert a compressive force on internal catheter 52, 
further securing it to the access port. Compression ring 140 also acts as 
a stress reliever to prevent kinking of the internal catheter 52 at its 
connection point to the access port. 
FIG. 21 illustrates another means for connecting internal catheter 52 to an 
access port. In this embodiment, exit end 144 has a reduced diameter 
projecting nipple 146 which internal catheter 152 is slid over. Like the 
embodiment shown in FIG. 20, compression ring 140 is provided which is 
slid onto the connection with FIG. 20. 
FIG. 22 illustrates an access port exit end 150 which features reversibly 
oriented barbs 152 which serve to securely engage the inner surface of 
internal catheter 52. Again, compression ring 140 is used to enhance the 
security of the connection of the internal catheter to exit end 150. 
FIG. 23 illustrates still another approach toward connecting internal 
catheter 52 to an access port exit end 156. This embodiment, like that 
shown in FIG. 20, defines an outer tubular portion 158, an inner tubular 
portion 160, with annular gap 162 therebetween. For this embodiment, 
however, the inside diameter surface of outer tubular portion 158 defines 
groove 164. Compression ring 166 has an exterior configuration including 
annular barb 168 which interlocks with groove 164 when the compression 
ring is slid onto exit end 156. 
An access port in accordance with a sixth embodiment of this invention is 
shown in FIG. 24 and is generally designated there by reference number 
210. Access port 210 principally comprises housing 212, outlet plug 214, 
and articulating valve assembly 216. 
As best shown in FIGS. 24 and 27, housing 212 defines a funnel-shaped 
entrance orifice 220, the function of which is to guide an access needle 
218 toward its center. Although orifice 220 is shown in the shape of a 
circular cone, other configurations could be used such as elliptical or 
flattened cones could be used to define the orifice opening. Such 
alternative shapes could be used to decrease the profile height of the 
device. Any configurations used for orifice 220 must posses a decreasing 
cross-sectional area for the purpose of guiding the access needle to a 
focus point. At the base of the orifice cavity shown in FIG. 27 is a 
reduced diameter guide passageway 222. Guide passageway 222 is straight 
and has a diameter only slightly greater than a diameter of elements which 
are desired to be passed into port 210. 
Outlet plug 214 is externally threaded which enables it to be attached to 
the end of housing 212 opposite entrance orifice 220. Outlet plug 214 
defines an externally barbed projecting hollow post 224 which enables an 
internal catheter 226 to be slid onto the post and attached to the access 
port as shown in FIGS. 24, 25 and 26. Hollow post 224 can be intentionally 
bent as shown in FIG. 27 to prevent needle 218 from passing entirely 
through the device in which case it could damage internal catheter 226. As 
is best shown in FIG. 27, once assembled together, housing 212 and outlet 
plug 214 define an internal cavity 228 which accommodates leaflet valve 
assembly 216. As shown in FIG. 27, cavity 228 is in an area of increase 
volume defined by a pair of conical surfaces 230 and 232, with conical 
surface 230 joining with guide passageway 222 and conical surface 232 
joining with exit plug post 224. 
Mounting plate 234 is attached or formed integrally with housing 212 and 
provides a means of mounting access port 210 to support tissues within a 
patient either with or without using sutures, surgical staples, etc. 
Leaflet valve assembly 216 shown in FIG. 27 includes a pair of elastic 
leaflet valve discs 236 and 238. Each of the elastic discs include slits 
extending from their geometric center and radially outward toward the 
perimeter of the elastic disc to define three separate flaps or leaves 
240. Elastic discs 236 and 238 are stacked against one another in a manner 
to disalign cuts 239 so that the leaves 240 of each disc overlies the cuts 
in the other to enhance the sealing characteristic of the leaflet valve 
assembly. As shown in FIG. 27, when housing 212 and outlet plug 214 are 
assembled together, the outer periphery of elastic discs 236 and 238 are 
slightly compressed to provide a seal which prevents fluids from leaking 
around the outer edges of the elastic disc elements. 
FIG. 26 shows an optional disc ring valve element 250 (not shown in FIG. 
27) which is provided to further enhance the sealing characteristics of 
valve assembly 216. Disc element 250 is donut shaped and has a hole 252 
through its center, which has a diameter slightly smaller than the needle 
or catheter which port 210 is designed to accommodate. The inventors have 
found that a valve element 250 having a durometer hardness of 50 Shore A 
and a thickness of 0.040 inches operates with the desired characteristics 
in the present invention. Valve element 250 is positioned to be the first 
element encountered by the access needle. This orientation is provided to 
prevent the apexes of leaves 240 from damaging valve disc 250 or 
interfering with its sealing capability. 
Access port 210 in accordance with this invention is adapted to be accessed 
using a conventional hypodermic needle 218 or trocar with a sharp end, 
which can be hollow or solid depending on the intended application. Needle 
218 can be used by itself or with an external catheter 246, which the 
needle is slid through so that the needle and catheter combination (eg. 
the commercially available "ANGIOGATH".TM., product) can be pierced 
through the skin and positioned into port 210 allowing the needle to be 
later withdrawn, leaving catheter 246 inside port 210 to provide fluid 
flow into or from the patient. The introduced catheter 246 can be threaded 
into internal catheter 226 to any extent desired, preventing unintentional 
withdrawal of the introduced catheter. 
FIG. 25 shows access port 210 being accessed by a needle 18 and catheter 
246 combination. When the care provider desires to access port 210, needle 
218 is used to pierce the patient's skin at an area adjacent the port 
entrance orifice 220 and the needle is pushed into the port. Entrance 
orifice 220 receives the sharp end of needle 218 and guides it toward and 
into guide passageway 222. The guide passageway then orients needle 218 
and aims it to strike leaflet valve assembly 216 at the center of valve 
elements 236 and 238, which is the point of intersection of the cuts 239 
defining leaves or flaps 240. Guide passageway 222, therefore, guides 
needle 218 to strike leaflet valve assembly 216 in an area where cutting 
or damage to the elastic disc elements is minimized since the discs are 
most easily penetrated at their central region where their flexibility is 
greatest. 
In order to provide an acceptable resistance to damage of valve assembly 
216 by needle 218, it is believed that the diameter of passageway 222 
which is superimposed on disc 236 in FIG. 28 and designated by reference 
number 254, should be no larger than one-half the diameter of the slit 
portion of elastic discs 236 and 238 which is encompassed by a circle 
designated as diameter 256. Passageway diameters 254 greater than that 
ratio would permit an inserted needle with its sharp point to strike the 
leaflet valve assembly 216 at near its outer perimeter, where leaves 240 
are not as supple and are more likely to be pierced by the access needle 
than the center portion. Controlling the position of the inserted needle 
218 also protects elastic disc 250 from damage which would occur if the 
needle struck outside of hole 252. 
The conical surfaces 230 and 232 of valve cavity 228 are provided to 
accommodate the flexing of valve leaves 240 in both directions. When 
access needle 218 is inserted into access port 210, the leaves 240 are 
permitted to deflect toward hollow post 224. In addition, conical cavity 
232 insures that the access needle 218 or other introduced filament is 
properly guided to pass through hollow post 224 and into internal catheter 
226, if desired. Upon withdrawal of access needle 218 or catheter 246 from 
access port 210, conical surface 230 enables the leaves 240 of valve 
assembly 216 to be freely deflected in an opposite direction. 
During the step of inserting needle 218 into port 210, a positive 
indication of full insertion is felt by the attending care provider as 
needle 218, which is relatively rigid, engages the bent portion of hollow 
post 224. This stop is provided to prevent accidental damage to internal 
catheter 226. However, the introduced filament or catheter 246 which is 
more flexible than access needle 218 can be readily threaded past hollow 
post 224 to provide deep insertion. 
In addition to permitting the insertion of a needle 218 and catheter 246 to 
port 210, this invention would allow a guide wire to be introduced into 
the port through access needle 218 which could be fed through the device 
and into and through the internal catheter 246 to remove thrombosis or 
other clogging problems. Various other filaments type elements could also 
be used with port 210 such as optical fibers, electrical conductors, 
remote sensing systems, etc. 
Numerous materials may be used to form housing 212. Since housing 212 will 
be subject to being struck by sharp needles which must be redirected into 
guide passageway 222, it is desirable to form the housing or at least the 
surface of entrance orifice 220 of a hard material such as stainless steel 
or titanium or a hard ceramic. Soft materials such as plastics, if used to 
form the inside surface of entrance orifice 220 could be subject to being 
gouged by needle 218, preventing proper guiding of the access needle. 
Similarly, exit outlet plug 214 is subject to being struck by a sharp 
needle and should also be made of a hard metal material for the reasons 
mentioned in connection with housing 212. Elastic discs 236, 238 and 250 
can be made of numerous elastic materials such as silicone rubber. 
An access port in accordance with a seventh embodiment of this invention is 
shown in FIGS. 29 and 30 and is generally designated by reference number 
310. Port 310 is designed to be accessed using a sharp needle which passes 
into the port through funnel shaped entrance orifice 312. Port 310 also 
includes a mounting pad 314 defining a generally planer mounting surface 
and may include apertures 316 for sutures or staples further enabling the 
device to be secured to appropriate support tissue within the patient. 
Internal catheters 318 is shown attached to port 310 and is tunneled to a 
desired site within the patient. 
The embodiment shown in FIGS. 29 and 30 of this invention is presented to 
disclose two specific improvements to devices described previously, namely 
a modified entrance orifice 312 and an inclination of the device with 
respect to mounting pad 314. As best shown in FIG. 30, access port 310 is 
oriented such that the accessing needle 320 (and associated catheter or 
other introduced filament) shown in phantom lines enters the device at an 
angle, designated as angle A from a plane parallel to mounting pad 314. 
The inclined orientation of port 310 facilitates insertion of needle 320 
through the patient's skin 322, as shown in FIG. 30. 
The further improvement shown in FIGS. 29 and 30 for access port 310 
involves a removal of the upper surface of the housing in the area 
defining entrance orifice 312 shown as a recessed or scalloped region 324. 
Removing material and forming the discontinuity in the scalloped region 
324 has the effect of slightly enlarging the target area of entrance 
orifice 312, and also providing a more smooth surface which is covered by 
the patient's skin, thus making the device somewhat less conspicuous to 
the patient and possibly less irritating. 
Although the features of access port 310 discussed in conjunction with 
FIGS. 29 and 30 are employed in a port of the type shown in FIG. 24, these 
improvements could also be incorporated into ports having various 
constructions and internal features including other ports which are 
described in this application and disclosed in the related applications. 
Referring now to FIG. 31, where access port 310 is shown in cross-section, 
entrance orifice 312 is in the form of a conical surface 313, which forms 
the outer perimeter of the orifice 312, that defines a relatively shallow 
cone having a relatively large included cone angle. Conical surface 313 
joins with a smaller constant diameter passageway 315 which is provided as 
a means of guiding inserted needle 320 toward an apex or focus area 317 of 
orifice 312. The focus area 317 joins with entrance passageway 319 which 
leads to an articulating valve assembly 350. The valve assembly 350 is 
only being briefly described in connection with FIG. 31 since it is 
described in greater detail with respect to the embodiment shown in FIG. 
33 through 40. 
For reasons which will be better described later in this specification, 
passageway 317 is intentionally oriented at a relatively great off-axis 
angle with respect to the central generating axis of entrance orifice 312. 
This off-axis orientation provides a curved passageway which is intended 
to prevent an introduced rigid needle 320 from undergoing the turn and 
directly engaging articulating catheter valve assembly 350. This feature 
accordingly distinguishes access port 310, and access port 330 which is 
further discussed hereafter, from the embodiments described previously 
which are designed to enable an inserted needle or rigid introducer to 
pass directly through an articulating valve. 
FIG. 32 illustrates access port 330 in accordance with an eighth embodiment 
of this invention. Access port 330 is primarily intended to be implanted 
in the chest wall region of a patient and generally comprises a funnel 
shaped entrance orifice 332, mounting platform 334, outlet tube 336, and a 
valving system which is described below. 
Mounting platform 334 can feature apertures 338 for enabling port 330 to be 
secured to underlying tissue within a patient using sutures, staples, etc. 
As best shown in FIG. 33, access port housing 352 also features a radially 
projecting protuberance in the form of a lug or ledge 340 projecting away 
from entrance orifice 332, and overlying outlet tube 336. By providing 
such an irregular feature on the device housing 352, the orientation of 
the port, and in particular, outlet tube 336 and internal catheter 318 can 
be readily ascertained through palpation of the device by the clinician. 
As will be better described in the following paragraphs, for some 
embodiments it is necessary to cause the introduced filament to undergo a 
rather sharp turn upon entrance into the device, and, therefore, knowing 
the orientation of the port can aid in feeding in the introduced filament. 
Lug 340 also provides the additional benefit of shielding implanted 
catheter 318 from needle sticks by the accessing hypodermic needle 320, if 
improperly aimed. 
Now with the reference to FIGS. 33 and 35, the configuration of entrance 
orifice 332 can be described in more detail. As is apparent from the 
figures, entrance orifice 332 is in the from of a pair of joined conical 
surfaces having differing cone angles. The first conical surface 344 which 
forms the outer perimeter of the orifice defines a relatively shallow cone 
having a relatively large included cone angle identified as angle B in 
FIG. 35. Conical surface 344 joins with a smaller diameter conical surface 
346 having an included angle, identified as angle C in the figure, which 
is smaller than angle B. The shallower conical surface 344 is provided as 
a means of guiding inserted needle 320 toward the apex or focus area 347 
of orifice 312. The relatively large angle B of conical surface 344 is 
provided so that the distance through access port 330 between its top 
planer surface and the internal valve system is kept as small as 
reasonably possible while providing a large target area for needle 320. 
This total distance is significant in that presently employed catheters 
which are fed over needles (eg. "ANGIOCATH" ) have a relatively short 
length, i.e. approximately two inches. It is desirable to allow such 
existing needles and catheters to be used with port 330, and at the same 
time, insure that the introduced catheter is securely inserted into the 
access port and engaged with the internal valve. Conical surface 346 is 
provided with a smaller included angle as a means of securely engaging 
introduced needle 330 and restraining it from radial motion once it is 
inserted and becomes rested in focus area 347. 
While the benefits of the configuration of entrance orifice 312 are 
achieved in accordance with the illustrated embodiment using two joined 
conical segments, it is fully within the scope of this invention to 
provide an entrance orifice defined by various other surfaces having a 
progressively decreasing cone angle as measured as shown in FIG. 35 when 
moving from the outer perimeter of entrance orifice 332 to the focus area 
347. For example, a paraboloid surface could also be provided for orifice 
332. In addition, entrance orifice 332 could be defined by a surface which 
is a asymmetrical in the sense of not being a surface of revolution about 
an axis through the orifice. Many surfaces can be imagined providing the 
benefits of the invention through providing a progressively smaller cone 
angle or target surface as the focus area is approached. 
As is shown in FIG. 35 the relatively large angle of conical surface 344 
serves to provide a low height between the upper surface of access port 
330 and articulating valve 350. As mentioned previously, this is 
advantageous since standard introduced catheters have a relatively short 
length and it is desirable to make sure they are fully engaged with the 
articulating valve to preclude inadvertent withdrawal. 
The focus area 347 of entrance orifice 332 joins with entrance passageway 
348 which leads to an articulating valve assembly 350. Passageway 348 is 
intentionally oriented with respect to the central generating axis of 
entrance orifice 332 at a relatively great off-axis angle, shown as angle 
D in FIG. 32 of about 60 degrees. As with the embodiment of FIG. 31, this 
off-axis orientation provides a curved passageway which is intended to 
prevent an introduced rigid needle 320 from undergoing the turn and 
directly engaging articulating valve assembly 350. Again, this feature 
accordingly distinguishes access port 330 from the embodiments described 
previously which are designed to enable a rigid introducer or needle to 
pass directly through the articulating valve. The feature, however, can be 
readily adapted and used with the previous embodiments. 
Housing 352 is preferably made from a hard material, such as a metal, which 
will not be gouged or engaged by the accessing needle 320. For example, 
titanium or another hard metal could be used to form the entrance housing 
352, or could be used merely to form the surface of entrance orifice 332. 
As best shown in FIGS. 33 and 35, access port housing 352 and outlet plug 
354 define catheter valve cavity 356. As shown in these figures, cavity 
356 is bounded by a pair of conical surfaces including conical surface 358 
which joins with passageway 348, and conical surface 360 formed by outlet 
plug 354. The included angle defined by conical surface 358 is greater 
than that of conical surface 360. The conical surfaces 358 and 360 are 
provided to enable flexing of the elements comprising articulating valve 
350. 
FIG. 33 provides an exploded view of articulating valve assembly 350. The 
valve is comprised of a number of individual valve elements stacked 
together. The first valve element encountered when passing through valve 
350 from entrance orifice 332, is a ring or donut valve 362, which is 
comprised of a ring of elastomeric material with a central circular 
aperture 364. Access port 330 can be used with introduced catheters of 
various diameters. Ring valve 362 is not provided to seal directly against 
the outer periphery of all sizes of introduced catheters, but rather 
provides a reinforcing function for the remaining catheter valve elements 
and also services to orient and center the introduced catheter, as will be 
described in more detail below. The next two valve elements are leaflet 
valve discs 366 and 368. Valve discs 366 and 368 each define three or more 
leaves 370 which form an apex at the geometric center of each valve disc. 
As shown in FIG. 34, the leaves of each valve disc 366 and 368 are 
intentionally disaligned or indexed to an offset position so that the 
leaves are not directly overlapping. This indexing is provided to enhance 
the sealing capabilities of catheter valve 350. The next elements 
encountered in valve 350 are spacer ring 374 and finally another ring or 
donut valve 376 with central aperture 378. Aperture 378 has a diameter 
which is slightly smaller than any of the catheters which access port 330 
is designed to be used with, thus providing a firm perimeter seal for the 
introduced catheters. The elements comprising valve 350 are stacked 
together, inserted into valve cavity 356 and retained there through the 
threaded engagement between housing 352 and outlet plug 354. 
Since hollow post 336 of outlet plug 354 is not oriented parallel to the 
plane defining mounting pad 314, the hollow post is bent slightly as shown 
in FIG. 33 as a means of orientating implanted catheter 318 along the 
plane defining port mounting platform 334. 
FIGS. 35 through 38 are provided to show access port 330 in use, and in 
particular, show the process of introducing an external catheter into the 
device. FIG. 35 shows access port 330 implanted with a patient below the 
surface of skin 322. In FIG. 35, a hypodermic needle 320 is shown 
penetrating skin 322. Needle 320 is placed through catheter 382 of 
conventional design (eg. "ANGIOCATH"). Needle 320 and catheter 382 are 
inserted through the skin and into entrance orifice 332. Conical surface 
344 initially guides the needle into conical surface 346, and finally into 
nesting engagement in focus area 347. As stated previously, orifice 312 is 
made from a material which will not be gouged by needle 320, but rather 
will guide it into focus area 347. 
FIG. 36 shows accessing needle 320 being fully inserted into focus area 347 
and into passageway 348. Due to the inclination of passageway 348 from the 
entrance orifice, needle 320 cannot readily pass beyond the point shown in 
FIG. 36. Once this position is reached, the care provider has positive 
feedback that the elements are oriented properly since it is apparent that 
the needle cannot be readily inserted any further into access port 310. 
Once the point of FIG. 36 is reached, the care provider can slide catheter 
382 along needle 320 while holding the needle in position, thus forcing 
the tip of catheter 382 further into access port 330. FIG. 36 illustrates 
in phantom lines that external catheter 382 undergoes a bend as it is fed 
into engagement with valve 350. Catheter 382 does not necessarily become 
oriented precisely along the longitudinal axis of passageway 348 and, 
therefore, does not always initially engage articulating valve assembly 
350 at its center. Ring valve element 362 serves to aid in centering 
introduced catheter 382 to properly orient itself with respect to the 
remaining valve elements. As introduced catheter 382 is forced further 
into engagement with the catheter 350, it passes through leaflet valve 
discs 366 and 368. As discussed in the previous embodiments, the leaves 
370 can be readily opened by inserting the external catheter and the 
triangular shape of the leaves 370 serves to aid in centering the 
catheter. Finally, the introduced catheter passes through second ring 
valve element 376 having a relatively small aperture 378. Due to the 
centering functions provided by ring element 362 and the leaflet element 
366 and 368, the introduced catheter becomes accurately aligned with and 
forced through aperture 378. Aperture 378 is sized to provide a perimeter 
seal around the introduced catheter 382. A fully inserted catheter is 
shown in FIG. 38. 
The design of articulating valve 350 according to this embodiment provides 
a number of significant features. By providing spacing ring 374, 
deflection of leaflet valve leaves 370 in the direction of the insertion 
of catheter 382 is freely permitted. When the introduced catheter passes 
through the leaflet valves, leaves 370 are permitted to deflect as shown 
in FIGS. 37 and 38 without significant restriction caused by the presence 
of ring valve element 376. However, upon withdrawal of introduced catheter 
382, reverse deflection of valve leaves 370 causes them to be reinforced 
by the close proximity of valve element 362, thus providing a relatively 
greater amount of friction during withdrawal versus insertion of catheter 
382. This difference in insertion versus withdrawal friction is a 
desirable feature since it allows the catheter to be freely inserted into 
the port, yet firmly engages the inserted catheter to prevent inadvertent 
withdrawal of it during infusion. 
The differing cone angles provided by catheter valve cavity conical 
surfaces 358 and 360 also provide several other functions. The relatively 
large angle of conical surface 358 is provided to place the passageway 348 
in close proximity to catheter valve 350. This enhances the "targeting" 
function to ensure that catheter 382 strikes the valve 350 at or near its 
center where it can be easily deflected and is guided into a proper 
engagement with ring valve element 376. This large cone angle also serves 
to limit the degree of deflection of ring valve element 362, thus 
increasing withdrawal friction. The relatively small cone angle of conical 
surface 360 is provided to guide the introduced catheter smoothly into 
hollow post 380 and provides clearance to permit relatively unrestricted 
deflection of leaflet valves 366 and 368 and ring valve element 376. 
FIG. 39 shows another embodiment of an articulating valve assembly and is 
designated by reference number 386. Valve assembly 386 has a number of 
elements identical to valve assembly 350 described immediately above, and 
the common elements are designated by common reference numbers. Valve 
assembly 386 differs from the previous embodiment in that spacer ring 374 
is replaced with another donut or ring valve element 388, having an 
internal circular aperture 390. The function of ring valve element 388 is 
to reinforce leaves 370 of valve disc 368 as a means of enhancing the 
sealing capabilities of valve assembly 386. The diameter of aperture 390 
is chosen to be larger than any introduced catheter 382 with which valve 
assembly 386 would be used. 
FIG. 40 shows yet another embodiment of valve assembly according to this 
invention and is designated by reference number 394. This embodiment also 
features a number of elements common to that of valve assembly 350 which 
are further identified by like reference numbers. Valve 394, however, 
features a flapper type valve element 396 having a central flap or leaf 
398. Flapper valve 396 is provided to act as a check valve providing 
enhanced resistance to reverse fluid leakage since flap 398 is actuated by 
fluid pressure into sealing engagement with valve disc 376. Flap 398 is 
readily deflected upon the insertion of catheter 382 or another flexible 
introduced filament. 
An access port in accordance with a ninth embodiment of this invention is 
shown in FIGS. 41 and 42 and is generally designated by reference number 
410. Access port 410 is designated to allow a sharp needle to access the 
device for purposes including infusing drugs or other fluids in the 
patient or withdrawing fluids from the patient. Access port 410 generally 
has housing 412 which defines a generally funnel shaped entrance orifice 
414. Entrance orifice 414 has a decreasing cross-sectional area which ends 
at housing passageway 416. The shape of entrance orifice 414 serves to 
guide a needle into passageway 416. To that end, the surface of housing 
412, forming orifice 414, is a hardened material, such as titanium, which 
has been found to be acceptable for this purpose. 
Housing 412 together with outlet plug 418 define valve chamber 420 located 
between passageways 416 and 422. As shown, the protruding catheter 
connector tube 424 of outlet plug 418 is bent to provide a positive means 
for preventing an introduced needle from passing entirely through the 
device and potentially damaging a soft elastomeric implanted catheter 426. 
Connector tube 424 does, however, permit more flexible filaments, such as 
catheters, guide wires or optical fibers, to pass into implanted catheter 
426. Mounting pad 428 enables the device to be conveniently mounted to 
subcutaneous support tissue, preferably but not exclusively using sutures, 
staples, or fasteners in general. 
Valve assembly 434 is disposed within valve chamber 420 and is best 
described with reference to FIG. 43. Valve disk 436 is made of an 
elastomeric material such as silicone rubber and is positioned in valve 
chamber 420 closest to entrance orifice 414. Disk 436 has a central 
aperture 438 defining a valve seat which is intended to seal against the 
introduced needle or filament upon insertion into access port 410, as will 
be described in more detail as follows. Stacked directly against disk 436 
is sealing member 440 which is preferably made, at least partially, of a 
hard material such as a metal. Sealing member 440 as shown in FIGS. 41, 
42, and 43 is a circular metal disk having three cuts intersecting at the 
center of the disk and extending radially to the outer perimeter but 
stopping short of the perimeter, thus defining three separate cantilever 
supported leaves 442. Each of leaves 42 is locally deflected from the 
plane of the disk at the disk center to define a segment 443 which combine 
to define conical sealing plug 444. Plug 444 has an external generally 
conical surface 446 with its center defining a concave surface 448. 
Sealing member 440 can be made from a flat sheet of metal stock which is 
locally deflected at the center area to define plug 444. Alternatively, 
the disk can be machined or cast such that the plug 444 is defined by a 
locally thickened region of the disk. 
Valve assembly 434 also incorporates an additional leaflet valve element 
452 formed from a flat sheet of elastomeric material. Valve element 452 
defines radial cuts which join at the geometric center of the disk, 
defining separate valve leaves 454. 
As shown in FIGS. 41 and 42, the three elements comprising valve assembly 
434, namely valve disk 436, sealing member 440 and leaflet valve 452 are 
stacked directly against one another and are trapped in position between 
access port housing 412 and outlet plug 418. As shown in the Figures, 
housing 412 defines a relatively small diameter passageway on the side of 
valve assembly 434 closest to entrance passageway 416. In this manner, 
seal element 436 is constrained against deflecting toward entrance orifice 
414 except at near its central area defining aperture 438. On the opposite 
side of valve assembly 434, outlet plug 418 defines a large diameter area 
for the deflection of the leaves of valve elements 440 and 452. 
The operation and cooperation of the elements defining access port 410 will 
now be described with particular reference to FIGS. 41 and 42. FIG. 41 
shows the configuration of valve assembly 434 when access port 410 is in 
its normal condition, implanted within the patient and not being used for 
access. In that condition, the segments of sealing member 440 making up 
sealing plug 444 project into and seal against disk aperture 438 which 
acts as a valve seat. Plug 444, having a conical outside surface 446, 
presses against disk aperture 438, causing it to be stretched and 
enlarged. Due to the contact between disk 436 and sealing member 440, a 
seal against fluid leakage is provided. 
Leaflet valve element 452 is provided to enhance the level of sealing by 
preventing fluid leakage between sealing member leaves 442. In the normal 
condition of the device as shown in FIG. 41, the valve leaves 454 meet to 
provide a fluid seal. As shown in FIG. 43, as a means of providing 
enhanced fluid sealing, the orientation of the cuts defining leaflet valve 
leaves 454 and the cuts defining the individual sealing member leaves 442 
are off-set or indexed so that they are not in registry. 
FIG. 42 shows the orientation of the elements of access port 410 upon 
insertion of accessing external needle 58. Housing orifice 414 and 
passageway 416 serve to direct and orient needle 458 such that the sharp 
point of the needle strikes concave surface 448 of plug 444. Due to the 
enlargement of valve disk aperture 438 through its interaction with plug 
444, the sharp point of the needle does not strike valve disk 436. As 
needle 458 is forced through the device, sealing member leaves 442 are 
forced to deflect in the direction of the outlet plug passageway 422. This 
movement of leaves 442 causes the segments defining plug 444 to move from 
engagement with disk aperture 438 which is allowed to contract in 
diameter. The undeformed diameter of aperture 438 is selected so that it 
will form a fluid seal against needle 458 (or another introduced filament 
such as a catheter, around the needle, which can be left in the device 
after the needle is removed). Continued deflection of leaves 442 allows 
free passage of the needle 458. Such deflections also causes valve leaves 
454 to separate allowing passage of needle 458 without valve leaves 454 
being damaged by contact with the needle point. 
As is evident from the above description of the operation of access port 
410, repeated access using needle 458 will not damage the device since the 
needle repeatedly strikes the hard material forming plug 444. Access port 
410 also permits the introduction of other external filaments, such as an 
external catheter, optical fiber or guide wire, provided that it has 
sufficient rigidity to deflect the valve elements in the manner previously 
described. Access port 410 could also enable external filaments to be 
introduced via needle 458, either fed through its center passageway or 
introduced around the needle 458 like a typical angiography catheter. 
FIG. 44 illustrates an access port 460 incorporating a valve assembly 462 
in accordance with the tenth embodiment of this invention. This 
embodiment, along with those described elsewhere in this specification, 
has elements and features identical to those of the ninth embodiment which 
are identified with like reference numbers. FIG. 45 illustrates valve 
assembly 462 which includes a valve disk 436 identical to that previously 
described. The distinction of this embodiment over valve assembly 434 is 
that the sealing member 464 which defines plug 470 is a composite 
structure. Sealing element 464 is formed from an elastomeric or flexible 
base disk 466 having a number of radially projecting cuts defining 
individual leaves 468 as in the case of sealing member 440 described 
previously. Attached to leaves 468 near the center of base disk 466 are 
plug segments 470 which together define a sealing plug 472 as in the prior 
embodiment which are made of a hard material such as metal. Plug elements 
470 are bonded or otherwise structurally affixed to disk 466. 
In use, valve assembly 462 operates in a manner consistent with the 
description of valve assembly 434. A principal advantage of the 
configuration of valve assembly 462 is that sealing element disk 466 
performs the combined functions of sealing, as with the leaflet vale 
element 452 of the first embodiment, and supporting plug segments 470. 
FIGS. 46 and 47 illustrate an access port 478 in accordance with an 
eleventh embodiment of this invention. Access port 478 has valve assembly 
480 with a valve disk 436 identical to that present in the ninth and tenth 
embodiments. In this embodiment, however, sealing member 482 is a unitary 
structure which includes plug element 484 attached to a mounting ring 486 
via a cantilever arm 488. As with the prior embodiments, plug 484 defines 
an external conical surface 490 and a central concave surface 492. In this 
design, however, the plug 484 is a unitary element. 
In operation, valve assembly 480 operates as like those of the prior 
embodiments in that in a normal condition without an external filament 
inserted within the access device, plug 484 is in sealing engagement with 
disk aperture 438. Upon the introduction of an external filament such as 
needle 458, engagement between the needle and sealing plug 484 urges it 
out of engagement with disk aperture 438, and deflects it sufficiently to 
allow passage of the needle, as shown in FIG. 47. This process also 
results in the contraction of the diameter of aperture 438, causing it to 
constrict around the introduced filament. A significant benefit of valve 
assembly 480 results from the fact that plug 484 is a unitary structure 
and, therefore, does not inherently provide a fluid leakage path. In the 
normal condition, with plug 484 against disk aperture 438, a fluid seal is 
provided and, therefore, additional sealing elements, such as a leaflet 
valve 452 shown in the tenth embodiment, are unnecessary. 
FIGS. 48 and 49 provide an illustration of access port 502 in accordance 
with the twelfth embodiment of this invention. This embodiment features a 
modified housing 504 and outlet plug 506. Housing 504 forms a small 
diameter counter bore 508 extending toward entrance orifice 414. Piston 
element 510 is positioned within housing cavity 512 and includes a central 
filament passageway 514. Piston 510 butts against elastomeric bushing 516 
having passageway 517, which is trapped within counterbore 508. The head 
of piston 510 forms a dished concave surface 518 which supports valve ball 
520. Piston surface 518 is formed to position ball 520 such that it is 
displaced from alignment with piston passageway 514. Outlet plug 506 forms 
a generally flat surface 522 within housing cavity 512 which provides for 
movement of ball 520, as is described in more detail below. 
Operation of access port 502 will be described with reference to FIGS. 48 
and 49 FIG. 48 represents the orientation of the elements comprising the 
device while inserting access needle 458. As is shown in FIG. 48, access 
needle 458 engages ball 520 off-center. Continued insertion of needle 458 
causes ball 520 to be displaced upward to the position shown in FIG. 49. 
During such displacement, piston 510 is caused to move toward entrance 
orifice 414 as ball 520 "rides out" of concave surface 518. This 
displacement of piston 510 compresses bushing 516. Since bushing 516 is 
trapped within counterbore 508 its axial compression causes bushing 
passageway 517 to constrict, thus causing it to seal against the 
introduced needle or other filament. As shown in FIG. 49, once ball 520 is 
fully displaced, free passage to the exit passageway 524 is provided. When 
needle 458 is completely removed from the device, ball 520 reseats in its 
position within concave surface 518 which provides a fluid seal. It would 
be possible to enhance the fluid seal provided by ball 520 in its normal 
position by utilizing an O-ring or other elastomeric valve seat (not 
shown) installed either on outlet plug 506 or a piston 510 and engaging 
the ball 520. 
While the above description constitutes the preferred embodiments of the 
present invention, it will be appreciated that the various embodiments of 
the invention are susceptible of modification, variation and change, 
including the combining of various features from the several embodiments, 
without departing from the proper scope and fair meaning of the 
accompanying claims.