Patent Publication Number: US-9427554-B2

Title: Modular implantable medical device

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims priority to and is a divisional of U.S. application Ser. No. 12/174,582 filed on Jul. 16, 2008, the entire contents of which are herein incorporated by reference as part of this application. 
    
    
     BACKGROUND OF THE INVENTION 
     1 . Field of the Invention 
     The present invention relates generally to the field of medical devices and in particular to the field of long term, implantable devices for permitting access to a patient&#39;s inner physiology. 
     2 . Summary of the Related Art 
     Medically treating a patient often requires long term placement of a medical device across one or more organ systems to establish access to a specifically targeted interior body site for diagnostic or therapeutic purposes. One common example is the establishment of percutaneous vascular access for purposes of administering liquid therapeutic agents, removing bodily fluids for testing or monitoring, treating bodily fluids before being returned to the body, and/or disposing of bodily fluids. 
     Particularly in the case of administering fluids to, or removing fluids from, the body continuously or periodically over an extended time period, those skilled in the medical arts typically use what are known as “permanent” catheterization techniques. These techniques employ implanted devices such as tunneled central venous catheters (CVCs) that remain implanted for durations ranging from a few weeks to years. Examples of such implanted and related medical devices exist in the following references, which are incorporated herein by reference: U.S. Pat. No. 4,266,999 (Beier); U.S. Pat. No. 4,405,305 (Stephen et al.); U.S. Pat. No. 4,488,877 (Klein et al.); U.S. Pat. No. 4,668,222 (Poirier); U.S. Pat. No. 4,897,081 (Poirier et al.); U.S. Pat. No. 4,935,004 (Cruz); U.S. Pat. No. 5,098,397 (Svensson et al.); U.S. Pat. No. 5,100,392 (Orth et al.); U.S. Pat. No. 5,242,415 (Kantrowitz et al.); U.S. Pat. No. 5,662,616 (Bousquet); U.S. Pat. No. 5,823,994 (Sharkey et al.); U.S. Pat. No. 5,830,184 (Basta); U.S. Pat. No. 5,848,987 (Baudino et al.); U.S. Pat. No. 5,882,341 (Bousquet); U.S. Pat. No. 5,989,213 (Maginot); and U.S. Pat. No. 6,033,382 (Basta). Examples of therapeutic regimens requiring such long-term continuous or periodic access to a specific internal body location include parenteral feeding, chemotherapy, antibiotic administration, dialysis, and chronic anesthesiology. 
     Generally, the type of procedure that a patient requires dictates whether a physician will utilize an acute, short term catheterization technique, or a chronic, long term catheterization technique. For example, establishing a state of general anesthesiology in preparation for a surgical procedure typically involves placing a CVC in a patient&#39;s blood vessel for a relatively short period of time, such as a few minutes to a few hours, and then removing the catheter once the surgery is finished and the patient is revived. When performing such an anesthesiology procedure, a physician commonly uses a short term catheterization technique to place a drug delivery catheter in a blood vessel of the patient. 
     In direct contrast to this example of short term CVC placement, a physician performing a hemodialysis procedure in a patient suffering from chronic kidney failure may place a CVC in one of the patient&#39;s blood vessels for a relatively long period of time. Such a patient typically requires dialysis sessions three times per week for an indefinitely extended period of time. Healthy kidney function ensures removal of fluid, chemicals, and wastes typically filtered from a person&#39;s blood. Hemodialysis removes these elements by sending a patient&#39;s blood to an external artificial kidney machine via the permanent vascular access, often established by placement of a long term catheter within the patient. A patient who is involved in such a hemodialysis regimen may need a catheter placed in a blood vessel for weeks, months, or years in order to provide a ready means for vascular access into that patient&#39;s bloodstream to enable these frequent life saving dialysis treatments. 
     Long term catheterization techniques typically entail inserting a catheter into a patient using a “tunneled catheter technique.” This procedure involves inserting a long term catheter into the patient through an incision in the skin and then routing the catheter for several centimeters under the skin before entering deeper regions of the body. Despite routine use, conventional tunneled catheter designs seriously compromise the ability of a patient&#39;s skin to protect the patient&#39;s body from infection. As discussed in “Intravascular Catheter-Related Infections: New Horizons and Recent Advances” (Raad et al.,  Arch Internal Medicine/Vol  162, Apr. 22 2002, Pages 871-878.), catheter-related infections are frequent events and present a potentially fatal health problem. High morbidity rate and high procedural cost are characteristics of typical long term tunneled catheter usage. The primary reason that the use of conventional catheters leads to a high rate of infection is that microorganisms enter the body through the skin incision. A conventional tunneled catheter device may include a tissue ingrowth cuff that acts as a barrier for micro-organisms entering the body and that anchors the catheter in the subcutaneous tunnel. Such a conventional device, however, still fails to prevent undesirably high infection rates. This is because standard cuff designs are designed for positioning within a subcutaneous tunnel rather than at the skin entry site, which is the most effective location at which to position a tissue ingrowth cuff for preventing infection. 
     Furthermore, in order to function properly over extended periods of time, many types of long term tunneled catheters require placement of their tips in a very specific high blood flow location, typically the Superior Vena Cava/Right Atrial Junction (SVC/RA). The turbulent flow in this location ensures rapid mixing and systemic distribution of therapeutic agents throughout a patient&#39;s vascular system, and also minimizes the risk of thrombus forming on the catheter&#39;s tip and leading to catheter dysfunction. Skilled clinicians are acutely aware of the need for highly precise catheter tip placement because they frequently diagnose and resolve catheter complications associated with improper tip placement. With conventional tunneled catheter designs, the ability to precisely adjust the position of the catheter tip in the SVC/RA depends largely on a freedom to position and adjust the tissue ingrowth cuff anywhere along the length of a subcutaneous tunnel. 
     Some tunneled catheter devices include adjustable dermal tissue ingrowth cuff assemblies. For example, the apparatus and methods disclosed in U.S. Patent Application No. 2004/0236314 to Mark A. Saab (Saab), incorporated herein by reference, allow a physician to place a modular dermal tissue ingrowth cuff assembly precisely within a skin incision site and subsequently adjust the location of the distal (internal) tip of a catheter assembly associated with the tissue ingrowth cuff assembly. This device comprises a base (or port) having tissue ingrowth material thereon for securely anchoring the port at the incision site. A physician using such a device, therefore, has the ability to position the catheter tip precisely at the desired body site without disturbing, moving, or stressing the fixed tissue ingrowth cuff. Positioning the modular tissue ingrowth cuff at the skin incision site enables the skin to heal into the device, and regain its ability to protect the patient from infection. 
     Such advanced tissue ingrowth cuff assemblies have resulted in numerous improvements related to patient care and well being, but they fail to anticipate or address several practical implementation issues. First, these existing devices typically require one or more conduit connections to the port (base) to establish a continuous and reliable sealed fluid path between the inner and outer regions of the patient&#39;s body. A clinician implanting such a device and connecting conduits to the base (port) disposed within a subcutaneous pocket is unable to see the connection points during assembly and after assembly to ensure proper, secure connections. This problem is increasingly serious with small devices because the clinician loses a significant tactile advantage during assembly. Second, incorporating multiple connection mechanisms into the base (port) complicates assembly and creates more junctions at which the device may fail. Third, having multiple mechanical connections to the base (port) prolongs the medical procedure and unnecessarily complicates the adjustment of the device to suit a patient&#39;s physiology. Also, these devices fail to enable a clinician to determine where to trim the conduit to ensure proper distal tip placement within a patient&#39;s anatomy. Requiring a clinician to connect one or more elements to the port therefore increases difficulty of use, increases manufacturing cost, prolongs the medical procedure, and, most importantly, decreases reliability of the device. 
     A need therefore exists for a subcutaneous port that anchors a transcutaneous conduit, protects a patient from infection, and requires no conduit fluid path connections to the port. Furthermore, in cases requiring modular conduit, for example when the distal tip requires precise placement, a need exists for a device that supports a modular conduit having a single fluid path connection point inside the patient&#39;s physiology. A further need exists for a device that enables making and testing that conduit-to-conduit connection for proper assembly outside the patient&#39;s body within a clinician&#39;s view prior to positioning the connected modular conduit inside the patient&#39;s physiology. Lastly, a need exists for a device that facilitates using a simple and precise method of predetermining where to trim the conduit along its length prior to making the conduit-to-conduit connection to ensure proper final distal tip placement. 
     SUMMARY OF THE INVENTION 
     The present invention comprises a medical device that is capable of implantation within a patient for long-term treatments, such as catheterization procedures, and a method of using the device. The device of the present invention includes a base that functions as an implanted medical port capable of receiving, routing, and anchoring a treatment component, such as for example a fluid conduit, power cable, or fiber optic cable, that extends through the patient&#39;s skin into the patient&#39;s internal physiology. The port is shaped to maximize comfort and ease of installation, and thus a relatively flat and generally rectangular geometry is most preferable for a variety of applications. The device of the present invention is adapted to support, direct, and anchor the treatment component such that no fluid or energy connections are required between the port and the treatment component to provide diagnostic or interventional treatments. Thus, fluid or energy in the form of light, heat, microwaves, and radio frequency (RF) transmissions, for example, can be transported to or from the patient in a controlled manner through the treatment component without coming into direct contact with the port. The port and the treatment component are further equipped with tissue ingrowth surfaces that help further anchor the device and establish a biological seal between living tissue and the regions of the treatment device on either side of the port. 
     One embodiment of the device of the present invention comprises a unitary port equipped with a passage therein for receiving a flexible treatment component entering through one outer surface of the base and exiting through another surface. The passage through the port is sized such that the section of flexible treatment component passing through the port is in full contact with at least one portion of the port, preferably the surface at which tissue ingrowth is desired. Additionally, the passage through the port may guide a flexible treatment component supported therein in a non-linear and/or angled direction that optimizes the device&#39;s performance and patient comfort. 
     Another embodiment of the present invention comprises a modular implantable port for stabilizing a treatment component for long-term use. The modular implantable port comprises a first and second element designed for reversible engagement around a continuous portion of a treatment component, such as a conduit or electrical lead. The first element comprises engagement elements which cooperate with counterpart engagement elements on the second element for aligning and securely but reversibly engaging the second element with the first element. The first and second elements each further comprise a portion of a wall defining a support passageway and which cooperate to define a support passageway when the first and second elements are assembled in an engaged state. The support passageway is formed by assembling the first and second elements and is sized to accommodate a continuous portion of a treatment component. In some embodiments, the device further comprises a tissue ingrowth cuff material fixedly disposed on a surface of one or both of the first and second elements for securing the modular implantable port to adjacent tissue, such as but not limited to subcutaneous dermal tissue. 
     In another embodiment, the treatment component is a flexible conduit comprised of a proximal portion that passes through a subcutaneously placed port and terminates outside of the patient&#39;s body, and a distal portion that terminates inside the patient&#39;s body at a specific, more distal location chosen by the clinician. The flexible conduit may be modular such that the proximal portion and the distal portion may be connectable by a fastening means. A clinician may trim and connect the modular portions of the conduit independent of interactions with the port as part of the placement procedure within the patient. 
     In all embodiments, the utility of the device optionally may be enhanced by incorporating markings on one or more portions of the treatment component to establish a graduated series of reference points for measuring and trimming. A clinician may use these markings in conjunction with patient&#39;s physiological landmarks to adjust, modify, and otherwise optimize the placement of the device within the patient to maximize comfort, safety, and efficacy. 
     These and other features and advantages of embodiments of the present invention are described in greater detail below with reference to the following figures. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  depicts a general perspective view of an embodiment of the medical system the present invention. 
         FIG. 2A  depicts a top view of a unitary embodiment of the implantable port of the present invention. 
         FIG. 2B  depicts a top view of a modular embodiment of the implantable port of the present invention. 
         FIG. 2C  depicts an exploded perspective view of a modular embodiment of the implantable port of the present invention. 
         FIG. 2D  depicts an end view of a modular embodiment of a portion of the implantable port of the present invention. 
         FIG. 3A  depicts an exploded perspective view of an embodiment of the medical system the present invention. 
         FIG. 3B  depicts a perspective view of an embodiment of the medical system the present invention. 
         FIG. 4  depicts an embodiment of a conduit connector employed in a modular embodiment of the present invention. 
         FIG. 5A  depicts a front view of the preparations made to a patient prior to implantation of an embodiment of the medical system of the present invention. 
         FIG. 5B  depicts a front view of a patient during the process of implanting an embodiment of the medical system of the present invention. 
         FIG. 6A  depicts a schematic plan view of a modular embodiment of the medical system of the present invention after implantation and during measurement of the modular conduit prior to trimming. 
         FIG. 6B  depicts a schematic plan view of a modular embodiment the medical system of the present invention following measuring and retracting a portion of modular conduit in preparation for trimming. 
     
    
    
     DETAILED DESCRIPTION 
     The present invention provides a medical device that is capable of implantation within a patient for long-term treatments. The device of the present invention includes a base that functions as an implanted medical port capable of receiving, routing, and anchoring a treatment component, such as for example a fluid conduit, power cable or fiber optic cable, that extends through the patient&#39;s skin into the patient&#39;s internal physiology. The port is shaped to maximize comfort and ease of installation, and thus a relatively flat and generally rectangular geometry is most preferable for a variety of applications. The device of the present invention is adapted to support, direct, and anchor the treatment component such that no fluid or energy connections are required between the port and the treatment component to provide diagnostic or interventional treatments. Thus, fluid or energy in the form of light, heat, microwaves, and radio frequency (RF) transmissions, for example, can be transported to or from the patient in a controlled manner through the treatment component without coming into direct contact with the port. The port and the treatment component are further equipped with tissue ingrowth surfaces that help further anchor the device and establish a biological seal between living tissue and the regions of the treatment device on either side of the port. 
     As  FIG. 1  depicts, one embodiment of the present invention comprises a system  100  that provides long-term access to the inner physiology of a patient. One such application of this system  100  is providing long-term vascular access for various kinds of catheterization and/or dialysis procedures. In particular, the system  100  comprises an implantable device  200  further comprising a tissue ingrowth scaffold material  210  or similar device for enabling living membrane, such as skin, at the entry site into the patient&#39;s anatomy to heal into the implantable device  200  and block the path of pathogens that would otherwise infect the patient. The modular nature of one embodiment of the present invention facilitates efficient and effective placement of the system  100 , and in particular the implantable device  200  and a treatment component disposed therethrough, here depicted as a conduit system  300 . Although the following detailed description references a conduit system  300  adapted for fluid flow, such as a catheter for transporting fluid to and from an external region, through the skin, and into a patient&#39;s vascular system, the conduit system  300  may be any type of elongated treatment component capable of enabling interventional therapeutic usage or diagnostic usage. Such a conduit system  300  may be for example a catheter, a fiber optic cable, an electrical power cable, or any other type of energy transmission system extending either from an external region to an internal region of a patient, or from one region of a patient&#39;s internal physiology to another internal region. 
     As shown in  FIG. 1 , an embodiment of the system  100  comprises an implantable device  200  comprising a base, or port,  205  that is adapted for placement within a patient&#39;s physiology and a tissue ingrowth scaffold material  210  disposed on one or more surfaces of the port  205 . The implantable device  200  may be adapted for example for subcutaneous placement for stabilizing a treatment component such as a transcutaneous conduit system  300  for long-term use. Typically, medical ports are adapted for implantation beneath a patient&#39;s skin and connect to inner physiology via an implanted conduit of some sort. Clinicians then use a needle to intermittently access these conventional port designs through the skin. By comparison, the implantable port  205  of the present invention is capable of receiving, routing, and anchoring a medical treatment component or diagnostic component, such as for example a fluid conduit, power cable or fiber optic cable, that extends through the patient&#39;s skin, through the port  205  and into the patient&#39;s internal physiology, thereby eliminating a need for intermittent access through the skin with a needle. The port  205  of the present invention is shaped to maximize comfort and ease of installation, and thus a relatively flat and generally rectangular geometry is most suitable for a variety of applications. In embodiments, the implantable port  205  is manufactured from a biocompatible material or a combination of materials chosen from a group consisting of thermoset polymers, polyurethane, polysulfone, polycarbonate, silicone, stainless steel, and titanium. Additionally, the port  205  of the present invention is adapted to support, direct, and anchor the treatment component, such as the conduit system  300 , so that no connections are required between the port  205  and the treatment component, thereby enabling fluid, light, energy or other therapeutic or diagnostic matter to flow seamlessly through the treatment component without directly contacting the port  205 . 
     The port  205  further comprises a tissue ingrowth scaffold material  210  affixed to one or more surfaces of the port  205  for enabling tissue growth into the scaffold material  210 . In one embodiment, a biocompatible adhesive secures the ingrowth scaffold material  210  to the port  205 . In another embodiment, the tissue ingrowth scaffold material  210  is releasably attached, and in yet another embodiment, at least a portion of the tissue ingrowth scaffold material  210  is bioabsorbable. Preferably, at least a portion of the tissue ingrowth scaffold material  210  is bioabsorbable and secured to the port  205  by a biocompatible adhesive. The bioabsorbable portion of the tissue ingrowth scaffold material  210  may be a polymer such as but not limited to one of the following biocompatible polymers: polyglycolide, polylactide, l-lactide, poly(dl-lactide), polycolactide, poly(e-caprolactone), polydiaxanone, polyglyconate, and poly(lactide-co-glycolide). 
     In all embodiments, unitary and modular versions of the port  205  further comprise a support passageway  215  for supporting the conduit system  300  that passes from the exterior to the interior of a patient&#39;s anatomy. For example, the unitary port  205  of  FIG. 2A  and the modular embodiment of the port  205  shown in  FIGS. 2B through 2D  depict the support passageway  215  as formed through the port  205  from one surface to another so that a continuous section of the conduit  300  may pass therethrough. In one embodiment, the support passageway  215  is angled so as to angle the trajectory of a conduit system  300  disposed therein and tunneled into the patient&#39;s inner physiology. In the present embodiment, the conduit system  300  also comprises a tissue ingrowth sleeve  305 . With the conduit system  300  inserted into the support passageway  215 , the tissue ingrowth sleeve  305  intersects the tissue ingrowth scaffold material  210  affixed to a surface of the port  205 . As the embodiment of  FIGS. 1, 3A and 3B  depict in detail, the tissue ingrowth sleeve  305  is adapted for positioning within the passageway  215  so as to extend along the outer surface of the proximal conduit at least from an upper, skin-facing port surface to the skin surface, and also extends along at least a portion of the outer surface of the proximal conduit between a second port surface and the conduit connector and also contacts both the tissue ingrowth scaffold material  210  disposed on the upper surface of the port  205  and the living tissue around an incision site. The tissue ingrowth sleeve  305  and tissue ingrowth scaffold material  210  thereby form a continuous surface for contacting living tissue and promoting ingrowth and healing at and around the incisions into which the implantable device  200  and conduit system  300  are inserted. 
     In one embodiment depicted in detail in  FIGS. 3A and 3B  and  FIGS. 6A and 6B , the conduit system  300  is modular and comprises a proximal portion  310  having a continuous middle section that passes through the port  205  and a distal portion  315  adapted for deeper insertion into a patient&#39;s anatomy. During the placement procedure, a clinician may trim the distal portion  315  to an optimal length. Once trimmed to the optimal length, the distal portion  315  connects to the proximal portion  310  for a perfectly-sized fit within the patient&#39;s physiology. In one embodiment depicted in detail in  FIG. 4 , the proximal portion  310  and distal portion  315  connect by means of a connector  400  that establishes a leak proof connection at a subcutaneous conduit connection for uninterrupted fluid flow. This modular embodiment of the conduit system  300  is useful in cases where a distal tip  317  of the distal portion  315  has a specific design feature, such as a valve, a coating, or a particular geometrical shape requiring retention for proper use. Such a feature prevents trimming off the distal tip  317  to properly size the length of the distal portion  315 . A clinician instead may trim a proximal end  319  of the distal portion  315  of the modular conduit system  300  and then connect the trimmed proximal end  319  of the distal portion  315  to the proximal portion  310 . 
       FIG. 4  depicts one embodiment of a connector  400  that securely joins the trimmed distal portion  315  and the proximal portion  310  of a modular embodiment of the conduit system  300 . In this embodiment, the connector  400  is sized and configured on a first end  405  for connection with the proximal portion  310  and sized and configured on a second end  410  for connection with the distal portion  315  of the modular conduit system  300 . A clinician may preassemble the first end  405  with the proximal portion  310  prior to insertion into the port  205  and later assemble the second end  410  of the connector  400  with the distal portion  315  during the placement procedure. In the embodiment of  FIG. 4 , the second end  410  of the connector  400  is shaped for insertion into a double-D conduit configuration. In this configuration, fluid flows through the conduit system  300  within two back-to-back D-shaped inner passageways. The first end  405  of the connector  400  fits over the back-to-back D-shaped inner passageways of the distal end  312  of the proximal portion  310  and the second end  410  of the connector firmly inserts into the D-shaped inner passageways of the distal portion  315 . In one embodiment, the second end  410  of the connector  400  may further comprise barbs  412  for securely grasping the inner wall of the D-shaped inner passageways of the distal portion  315 . Additionally, the connector  400  may further comprise a push ring  414  that slideably engages the outer surface of the proximal end  319  of the distal portion  315  to further ensure a secure, leak proof connection between the second end  410  of the connector  400  and the distal portion  315  of the modular catheter system  300 . In yet another embodiment, the connector  400  may be preassembled to the distal portion  315 . Having the connector  400  preassembled to the distal portion  315  thus enables the clinician to adjust the final length of the assembled conduit system  300  by trimming the distal end  312  of the proximal portion  310 , which typically has no staggered tip or other specialized geometry requiring retention. In all embodiments, the connector  400  may comprise readily identifiable features that enable a clinician to accurately locate the connector  400  following implantation under the skin. For example, the connector may comprise a textured surface that appears under ultrasonic examination. Accurate identification of the location of the connector  400  would enable a clinician to make a skin incision adjacent to the connector  400  to regain access to the connector system  300 . This may be useful, for example, for the purpose of replacing the distal conduit  315  in the event of a malfunction, such as an occluded distal tip  317 , without disturbing the tissue ingrowth regions of the port  205  and proximal portion  310  of the connector system  300 . 
     Such a connector  400  enables several useful combinations of distinct design characteristics of the distal portion  315  and proximal portion  310  of the modular conduit system  300 . For example, as  FIG. 6B  indicates, in one embodiment, the proximal portion  310  comprises a proximal cross sectional area Bθ that may be larger than the distal cross sectional area Aθ of the distal portion  315 , and the first end  405  and second end  410  of the connector are sized accordingly to receive the proximal cross sectional area Bθ and distal cross sectional area Aθ. This relative enlargement of the proximal portion  310  will enhance the flow rate capabilities of the assembled conduit system  300 . Increasing the flow rate capability in this way enables a safe reduction in the distal cross sectional area Aθ of the distal portion  315 . A smaller distal portion  315  requires a less invasive insertion and smaller venotomy within the patient&#39;s physiology. Additionally, the modular embodiment of the conduit system  300  enables individual adjustment of the wall thicknesses in both the proximal portion  310  and distal portion  315 . This selective optimization enables improved kink resistance of the assembled conduit system  300 . Thus, the modular embodiment of the conduit system  300  enables an optimization and balance of three critical criteria: flow rate, kink resistance, and venotomy size. 
     Turning now to the design characteristics of the implantable device  200 , in one embodiment, the implantable device  200  may be a unitary device. A clinician may implement this unitary embodiment of the implantable device  200  in cases in which the conduit system  300  comprises no connector  400  or other element sized too large for insertion through the support passageway  215  of the port  205 . In one embodiment of the implantable device  200 , the port  205 , as depicted in  FIG. 2A , is a unitary device comprising a support passageway  215  formed therethrough and extending between and through two surfaces of the port, such as an upper, skin-facing surface and a lower, second surface. The support passageway  215  formed therein is sized and shaped for receiving an elongated conduit system  300  that slideably inserts therethrough. Additionally, one embodiment of the implantable device  200  further comprises a tissue ingrowth scaffold material  210  fixedly disposed on at least a portion of the upper surface of the port  205  so that a clinician may position the tissue ingrowth scaffold material  210  against an upper inner surface of the subcutaneous pocket to promote and enable tissue ingrowth and skin healing. In other embodiments, the tissue ingrowth scaffold material  210  may be fixedly disposed on another surface of the port  205  for positioning adjacent living tissue other than dermal tissue, such as internal organ tissue, for example, to enable and promote tissue ingrowth there. In other embodiments, the tissue ingrowth scaffold material  210  may be fixedly disposed on more than one discreet surface of the port  205  for promoting more than one area of tissue ingrowth with more than one adjacent area of living tissue. 
     The support passageway  215  of a unitary embodiment of the implantable device  200  further comprises an inner wall  216  that is substantially continuous and firmly grips the continuous portion of the elongated conduit. In one embodiment, a clinician may apply a biocompatible adhesive to the inner wall  216  for retaining the elongated conduit system  300  therein disposed. In another embodiment, the inner wall  216  of the support passageway  215  may comprise one or more gripping elements, such as but not limited to a plurality raised bumps or a plurality of raised ridges or raised rings adapted for retaining the conduit system  300  by friction force. In such an embodiment, a clinician may adjust the conduit system  300  within the passageway  215  by applying sufficient force to overcome frictional forces that otherwise retain the conduit system  300  in a secure, immobile position during tissue ingrowth and healing. 
     In the embodiment of  FIGS. 3A and 3B , the implantable device  200  is modular and thereby configured to accommodate a conduit system  300  having a connector  400  that is too large to fit through the support passageway  215 . The modular embodiment of the implantable device  200  comprises a modular embodiment of the port  205  further comprising a distal port component  220  and a proximal port component  230  that engage to form the complete port  205 . Both the distal port component  220  and proximal port component  230  have thereon biocompatible tissue ingrowth scaffold material  210 . This embodiment allows a clinician to align the conduit system  300  with the proximal port component  230  such that the connector  400  is disposed beyond the port  205  following subsequent engagement of the distal port component  220  with the proximal port component  230 . In one embodiment, this engagement of the proximal port component  230  and distal port component  220  of the port  205  further comprises encircling the tissue ingrowth sleeve  305  disposed on the proximal portion  310  of the conduit system  300 . This further establishes a continuous surface of tissue ingrowth scaffold material  210  disposed on the distal port component  220  and the proximal port component  230  and about the proximal portion  310  of the conduit system  300 . This continuous surface comprising the tissue ingrowth scaffold material  210  and the tissue ingrowth sleeve  305  provides an opportunity for living tissue adjacent to all incision sites to grow fully into the system  100  and thereby create a barrier that prevents infection. 
       FIGS. 2C through 3A  detail one embodiment the modular implantable device  200  having a distal port component  220  and a proximal port component  230  sized and shaped for insertion into a patient&#39;s anatomy and designed for reversible engagement around a continuous portion of a conduit system  300 . In one embodiment, the proximal port component  230  comprises engagement elements which cooperate with counterpart engagement elements on the distal port component  220  for aligning and securely-but-reversibly engaging the proximal port component  230  with the distal port component  220  so as to form a unified, firmly engaged, stable port  205 . The engagement elements and counterpart engagement elements may comprise any number of components capable of repeated disengagement and secure repeated engagement such as but not limited to snap fit mechanisms, pressure fit elements, and hook and latch features. 
     Additionally, in one embodiment, the engagement elements may include features that enable a clinician to assemble the modular port  205  in stages. In such an embodiment, the clinician may align the proximal port portion  230  and the distal port portion  220  in a semi-connected position such that the support passageway  215  is loosely formed around the conduit system  300 , and the conduit system  300  may move freely in the support passageway  215 . Once the clinician optimizes the position of the conduit system  300  and, in certain embodiments, the ingrowth sleeve  305  thereon relative to the support passageway  215  of the base  205 , the clinician may fully engage the loosely connected proximal port portion  230  and the distal port portion  220  to securely support the conduit system  300  therein positioned. In its fully assembled state, one embodiment of the modular embodiment port  205  exerts a compressive force onto the conduit system  300  to prevent movement and anchor the conduit system  300  while still enabling uninterrupted fluid flow through the conduit system  300 . Additionally, in another embodiment, the modular port  205  may be supplied to a clinician initially in a semi-connected position such that the clinician may not disassemble the port  205  and so that perfect alignment of the engagement elements and counterpart engagement elements on the distal port component  220  and proximal port component  230  already exists prior to insertion into a patient&#39;s physiology. This pre-aligned modular port  205  embodiment further aids a clinician in easily and accurately installing the port  205  and conduit system  300 . 
     In the embodiment of  FIGS. 2C through 3A , the engagement elements comprise interlocking elements and the counterpart engagement elements comprise receiving portions that are aligned to receive the interlocking elements. Specifically, the engagement elements comprise a plurality of tines  232  and the counterpart engagement elements comprise a plurality of slots  222  sized for securely receiving the plurality of tines  232 . The plurality of tines  232  are offset slightly from the plurality of slots and once engaged with the plurality of slots  222 , the plurality of tines  232  apply an outward force against an inner wall of the corresponding plurality of slots  222 . The plurality of tines  232  therefore remain securely positioned within the plurality of slots  222  as depicted in  FIGS. 1, 2B and 3B . In one embodiment, each of the plurality of tines  232  further comprises a bulbous, or barbed, end  234  having at least one angled or curved sidewall for guiding each of the plurality of tines  232  into a corresponding slot  222 . Each bulbous end  234  further may comprise an undercut portion  236  such that following engagement of the plurality of tines  232  within the plurality of slots  222 , each bulbous end  234  extends beyond the periphery of each corresponding one of the plurality of slots  222  and each corresponding undercut portion  236  presses against an outside wall of each of the plurality of slots  222 . The undercut portion  236  thereby prevents the corresponding tine  232  from retracting from a slot  222  without an application of inward force that counteracts the outward force emanating from the offset plurality of tines  232  and that pushes the undercut portion  236  of the barbed end  234  inside the slot  222 . 
     A clinician thus may selectively disassemble the modular embodiment of the port  205  by squeezing the bulbous ends  234  of the plurality of tines  232  toward one another to counteract the outward force imparted by the plurality of tines  232 . Applying such force to the bulbous ends  234  thus allows the plurality of tines  232  to realign with the plurality of slots  222  so that the distal port component  220 , which is no longer retained by the bulbous ends  234  and outward forces of the plurality of tines  232  disposed within the plurality of slots  222 , freely disengages from the proximal port component  230 . As  FIGS. 1, 2B and 3B  depict, the bulbous ends  234  are readily accessible to a clinician when the modular port  205  is assembled, and the clinician may access the bulbous ends  234  easily, readily imparting an inward force using fingertips or a surgical forceps, for example. 
     In addition to comprising engagement elements that produce a secure and reversible engagement between the proximal port component  230  and distal port component  220 , one embodiment of the port  205  further provides a shelf portion  238  above which the plurality of tines  232  extend. The shelf portion  238  receives the distal port component  220  thereon during engagement of the distal port component  220  and the proximal port component  230 .  FIG. 2C  depicts the shelf portion  238  which helps align and stabilize the two base (port) components during and after assembly. Additionally, in one embodiment, the port  205  is shaped for comfortable use, and the distal port component  220  and the proximal port component  230  each have a contoured upper surface to facilitate insertion into and removal from a patient&#39;s physiology. In one embodiment, the port  205  is substantially oval shaped and disk shaped such that its length is greater than its thickness, thereby providing a sturdy base for securing the conduit system  300  while imparting minimal trauma upon the patient. Additionally, the port  205  is preferably manufactured from a biocompatible material such as but not limited to thermoset polymers, polyurethane, polysulfone, polycarbonate, silicone, stainless steel, and titanium. The port  205  and any modular components thereof may be machined, extruded, injection molded or produced by any process, or combination of processes, enabling the formation of the critical elements and features herein described. 
     The distal port component  220  and the proximal port component  230  are thus designed for reversible but secure engagement, and the port  205  is designed for comfort during use. The support passageway  215  of the port  205  further enhances comfort and support. In modular embodiments, the distal port component  220  and the proximal port component  230  each further comprise a portion of a wall  216  defining the support passageway  215 . The proximal portion wall  216   a  and the distal portion wall  216   b  cooperate to define the support passageway  215  when the proximal port component  230  and distal port component  220  are assembled in an engaged state. The support passageway  215  thus is formed by assembling the distal port component  220  and the proximal port component  230  and is sized to accommodate a continuous portion of the conduit system  300  that passes through the port  205  from one surface to another. In all embodiments, the wall  216  of the support passageway  215  is substantially continuous and firmly grips the continuous portion of the catheter system  300  to secure that treatment component in place. The modular embodiment of the port  205  thus enables a clinician to disassemble the port  205  and further adjust the proximal portion  310  of the conduit system  300  by sliding the proximal portion  310  forward or backward as needed and then reassembling the distal port component  220  and the proximal port component  230  about the proximal portion  310 . 
     In addition to enabling adjustment of the conduit system  300 , the port  205  of the present invention provides a support passageway  215  that is sized to enable uninterrupted fluid flow through the conduit system  300  when the conduit system  300  is designed for such fluid flow, for example in cases in which the conduit system  300  comprises a catheter. Furthermore, in one embodiment, the longitudinal access of the support passageway  215  is angled between 0 and 90 degrees relative to upper surface of the port  205 . In preferred embodiments, the longitudinal axis of the support passageway  215  is angled between  35  and  55  degrees from the upper surface of the port  205 .  FIGS. 2B through 2D  depict the proximal portion wall  116   a  and the distal wall portion  116   b  which combine to form the angled support passageway  215 . The embodiment of the present invention having an angled support passageway  215  enables a more ergonomic use of the system  100  when implanted within a patient. Because the support passageway  215  is angled, the conduit system  300  exits the port  205  and the patient&#39;s physiology at an angle that enables comfortable positioning of the proximal portion  310  against the patient&#39;s body. This positioning prevents any application of uncomfortable torque on the conduit system  300  when implanted within the patient and maintains proper alignment of the conduit system without imparting any disruptive bends or kinks that might otherwise disrupt a smooth fluid flow through the conduit system  300 . 
     Turning now to a method of implanting and deploying the system  100 , the present invention is adapted for use across all patient sizes. Many non modular conduit designs, such as standard Hemodialysis catheters, cannot be trimmed because their distal ends have special tip geometries, and clinicians, therefore, must stock various preset lengths of conduit. Generally, proximal ends of conduits also cannot be trimmed because of assembly fittings that enable connections to dialysis machines. Manufacturers thus produce such catheters in a range of pre-determined, pre-cut lengths which may or may not fit perfectly within a particular patient&#39;s physiology. A clinician then must choose the length that most closely suits a patient&#39;s physiology. The need to stock multiple lengths of the same product is a disadvantage that is overcome by the modular approach of one embodiment of the system  100  of the present invention. 
     Interventional Radiologists, Vascular Surgeons, or Interventional Nephrologists are the types of clinicians who would place the system  100  of the present invention within a patient&#39;s physiology. Typically, a clinician prepares a patient for the procedure by thoroughly disinfecting the skin site and applying local anesthesia. As shown in  FIG. 5A , in one embodiment of the method of implanting the system  100 , the clinician prepares a patient for implantation of the system  100  by creating a skin incision  30  and forming a subcutaneous pocket  32  by blunt dissection. The subcutaneous pocket  32  is created to receive the port  205 . Using ultrasound guidance, the clinician then forms a venotomy  34  in the patient&#39;s internal jugular vein  36  using a micropuncture set (not shown) and Seldinger technique. The clinician then enlarges the venotomy  34  by switching out the micropuncture set for a guidewire  39  and peelable introducer sheath/dilator set  20  of sufficient size to accommodate the conduit system  300 . The clinician introduces a sharp tunneler tip  41  of the tunneling device  38  into the subcutaneous pocket  32  below the incision  30  and forcefully pushes the tunneler tip  41  under the skin towards the venotomy  34 , thereby creating a subcutaneous tunnel  42 . (The conduit system  300  eventually will travel through the subcutaneous tunnel  42  between the venotomy  34  and the pocket  32 .) The clinician then makes a small incision above the venotomy  34  to allow the tunneler tip  41  to protrude through the skin for eventual removal from the subcutaneous tunnel  42  at the venotomy  34  site. The clinician will leave the tunneling device  38  temporarily in place within and across the subcutaneous tunnel  42  while preparing the conduit system  300  for positioning. 
     If the distal tip  317  of the distal portion  315  of the conduit system  300  lacks a specialized tip feature, the clinician simply may trim the distal tip  317  to the required length for proper fit within the patient. In this instance, the conduit system  300  need not be modular and may be unitary. First, as  FIG. 5B  depicts, the clinician will insert the port  205  into the subcutaneous pocket  32  and form a skin opening  40  in the dermis above the subcutaneous pocket  32  through which the proximal portion  310  of the conduit system  300  will pass. The clinician then will insert the conduit system  300  through the skin opening  40 , through the support passageway  215  and out through the skin incision  30  that defines one edge of the subcutaneous pocket  32 . The clinician then will attach the distal tip  317  of the distal portion  315  of the conduit system  300  to a barbed end  35  of the tunneling device  38 , and pull the tunneling device  38  out of the subcutaneous tunnel  42  by the sharp tunneler tip  41  at skin puncture site for the venotomy  34 . Pulling the tunneling device  38  out of the subcutaneous tunnel  42  also pulls the attached distal portion  315  into and through the subcutaneous tunnel  42 . Once the distal tip  317  travels completely through the subcutaneous tunnel  42 , the clinician will disconnect the distal portion  315  from the tunneler tip  41  and discard the tunneling device  38 . 
     Once the conduit system  300  is initially positioned within the tunnel  42 , the clinician then may adjust the tissue ingrowth sleeve  305  to an optimal location relative to the port  205  and the skin opening  40 . The clinician thus ensures that the tissue ingrowth scaffold material  210  and the tissue ingrowth sleeve  305  form a continuous tissue ingrowth surface that directly contacts the upper inside surface of the subcutaneous pocket  32  surrounding the skin opening  40  and also directly contacts the surfaces of the skin opening  40  to promote and enable tissue ingrowth and skin healing that prevents infection at all incision sites. 
     With the proximal portion  310  properly adjusted, the clinician will then trim the distal tip  317  of the distal portion  315  so that the distal portion  315  will resides in a desired location within the patient once the clinician completes insertion of the distal portion  315  into the venotomy  34 . Next, the clinician will remove the guidewire  39  and dilator from the peelable introducer sheath  20  and immediately insert the trimmed distal portion  315  of the conduit system  300  through the peelable introducer sheath  20 . The clinician then will advance the distal portion  315  into the internal jugular vein  36  and deeper into the vascular system to the desired location. Once the distal tip  317  reaches its proper position, the clinician will make any needed adjustments to the conduit position and test the device for proper function. The clinician then will remove the peelable introducer sheath  20  by peeling it away from the distal portion  315  and out of the venotomy  34 . The clinician will suture the skin incision  30  to close the subcutaneous pocket  32 . The clinician also will suture the smaller incision at the venotomy  34  site to complete the placement procedure of the system  100  within a patient&#39;s physiology. 
     By comparison, if the conduit system  300  has a specialized feature on the distal tip  317  that precludes trimming that end of the distal portion  315 , a modular conduit system  300  comprising special trimming guides is preferred so that a clinician may adjust the length of the conduit system  300  by trimming the a proximal end  319  of the distal portion  315  without impacting the distal tip  317 , already positioned within the patient&#39;s physiology. Additionally, if the connector  400  is larger than the support passageway  215 , then a clinician may use the modular embodiment of the port  205  which has a proximal port portion  230  and a distal port portion  220  designed for reversible engagement. In one embodiment, a method of using the modular embodiment of the port  205  and modular conduit system  300  comprises first inserting the proximal port component  230  into the subcutaneous pocket  32  so that the tissue ingrowth scaffold material  210  is positioned against an inner tissue surface of the upper, outer flap of the subcutaneous pocket  32 . Next, the method comprises forming a skin opening  40  in the dermis above the subcutaneous pocket  32  through which the conduit system  300  will pass. A clinician then inserts the proximal portion  310  and connector  400  through the skin opening  40 , into the subcutaneous pocket  32 , past the proximal port component  230 , and out though the skin incision  30  that defines one edge of the subcutaneous pocket  32 . 
     Just as described above, the method then comprises attaching the distal tip  317  of the distal portion  315  of the conduit system  300  to a barbed end  35  of a tunneling device  38 . The clinician will advance the sharp tunneler tip  41  of the tunneling device  38  from the skin incision  30  towards the venotomy  34 , thereby pulling the distal portion  315  into and through a subcutaneous tunnel  42 . Once the distal portion  315  is positioned within the subcutaneous tunnel  42 , a clinician will disconnect and discard the tunneling device  38 . The clinician will adjust the position of the tissue ingrowth sleeve  305  to an optimal location relative to the proximal port component  230  and the skin opening  40 . Next, the method comprises inserting the distal port component  220  into the subcutaneous pocket  32  and connecting that distal port component  220  to the proximal port component  230  by sliding the plurality of slots  222  over the plurality of tines  232  until the plurality of barbs  234  snap into place. The clinician may press the distal wall portion  216   b  of the support passageway  215  over the distal portion  315  of the conduit system  300  and slide the distal port component  220  along the distal portion  315  until the distal port component  220  aligns with and fully engages the proximal port component  230 . Alternatively, in some embodiments, the clinician may opt to assemble the modular port  205  into an intermediate closure position which allows the clinician to further adjust the proximal portion  310  if needed while completing the placement procedure and before fully engaging the components of the modular port  205 . 
     Once the distal port component  220  fully engages with the proximal port component  230 , the unified port  205  comprises a continuous surface comprising the tissue ingrowth scaffold material  210  disposed on the port components  220 ,  230 , and the tissue ingrowth sleeve  305  affixed to the proximal portion  310  of the conduit system  300 . In one embodiment, at least a section of the tissue ingrowth sleeve  305  of the proximal portion  310  of the conduit system  300  is positioned between the distal port component  220  engaged with the proximal port component  230  and another section is positioned through the skin opening  40 . A continuous surface of tissue ingrowth scaffold material  210  therefore directly contacts an upper, inner surface of the subcutaneous pocket  32  surrounding the skin opening  40 . Additionally, the tissue ingrowth sleeve  305  directly contacts the surfaces of the skin opening  40 . This continuous contact between tissue ingrowth scaffold material  210  and the tissue ingrowth sleeve  305  with living tissue at and around the incision sites promotes and enables tissue ingrowth and healing that prevents infection at all incision sites. Lastly, the clinician will bring the distal end  312  of the proximal portion  310  outside of the patient via the skin incision  30  so that the connector  400  is easily reachable during assembly of the modular conduit system  300 . 
     Once the proximal portion  310  is positioned within the proximal port component  230  and once the proximal port component  230  and distal port component  220  are engaged, the clinician will advance the distal tip  317  of the distal portion  315  of the conduit system  300  deep into the patient&#39;s vascular system through the peelable introducer sheath  20 , until the distal tip  317  reaches a desired location  500  within the patient&#39;s vascular system, and the sheath can be removed. The excess length of the fully inserted distal conduit  315  extends outside of the patient at the pocket incision and aligns with the distal end  312  of the proximal portion  310  as shown in  FIGS. 5B, 6A, and 6B . Because the conduit system  300  is modular and marked for trimming, a clinician may easily and accurately size and position the distal portion  315  of this embodiment of the catheter system  300  within a patient&#39;s physiology while preserving a specialized feature of the distal tip  317 .  FIGS. 6A and 6B  depict one embodiment of the method of sizing and placing the distal portion  315  prior to connecting the distal portion  315  and proximal portion  310  via the connector  400  or some other connection means. 
       FIG. 6A  depicts the inserted distal portion  315  and proximal portion  310  of a modular embodiment of the conduit system  300  in relation to the subcutaneous pocket  32  and skin incision  30 . In one embodiment, both the distal portion  315  and proximal portion  310  comprise graduated markings  46  that enable a clinician to determine where to trim the proximal end  319  of the distal portion  310 . With the distal tip  317  disposed in a desired location  500  and with the connector  400  aligned adjacent to and/or resting directly over the subcutaneous tunnel  42  and outside a patient&#39;s body, a clinician may determine a point at which to trim the distal portion  315  so that the distal portion  315  and proximal portion  310  engage to form a continuous length that fits perfectly inside the tunnel  42  so that the distal tip  317  ultimately remains correctly positioned at the desired location  500 . A clinician may note the graduated marking  46  on the proximal portion  310  that most closely aligns with the skin incision  30  at the entrance to the subcutaneous pocket  32 . The clinician then may note the visible graduated marking  46  on the distal portion  315  that aligns most closely to the skin incision  30 . In one embodiment, the graduated markings  46  that comprise this novel measurement system are arranged such that subtracting the graduated marking  46  noted on the proximal portion  310  from the graduated marking  46  noted on the distal portion  315  provides guidance on where to trim the proximal end  319  of the distal portion  315  so that the distal portion  315  and proximal portion  310  engage to form an exact length needed to ensure proper placement of the distal tip  317  in the desired location  500 . As the example in  FIG. 6A  depicts, the distal portion  315  exhibits a graduated marking  46  reading “15” at the incision  30 , and the proximal portion  310  exhibits a graduated marking  46  reading “5” at the incision  30 . Subtracting “5” from “15” guides the clinician to trim the proximal end  319  of the distal portion  315  at the graduated marking  46  reading “10” to ensure proper placement of the distal tip  317  once the distal portion  315  connects to the proximal portion  310 . 
     As  FIG. 6B  depicts, the clinician may then partially retract the distal portion  315  of the conduit system  300  from the subcutaneous tunnel  42  to expose the calculated graduated marking  46  at which the clinician will trim the distal portion. Once the clinician trims the proximal end  319  of the distal portion  310 , the clinician may connect the distal portion  315  to the proximal portion  310  via the connector  400  and visually inspect and test the connector  400  to ensure proper alignment of the distal portion  315  and proximal portion  310  and to ensure a fluid tight connection. If necessary, the clinician can detach the distal port component  220  from the proximal port component  230  either fully or partially while retracting or advancing the proximal portion  310  as needed to facilitate the connection with the distal portion  315  of the conduit system  300 . The clinician then may advance the connector  400  into the subcutaneous tunnel  42  until the conduit system  300  is straight and the distal tip  317  returns to the desired location  500  as confirmed by the proper graduated markings  46  aligning once again with the skin incision  30 . If the clinician had disassembled the modular port  205  to facilitate connecting the distal portion  315  and proximal portion  320  of the conduit system  300 , the clinician then would reassemble the modular port  205  around the assembled, properly re-positioned modular conduit system  300 . 
     The modular embodiment of the conduit system  300  of the present invention thus provides a means for easily and precisely determining where to trim the distal portion  310  of the conduit system  300  to ensure proper placement of the distal tip  317 . Also, this modular conduit system  300 , in combination with the modular embodiment of the port  205 , enables a clinician to make adjustments to the position of the proximal portion  310  and connect the distal portion  315  and the proximal portion  310  outside of the patient&#39;s body and in plain sight. This solves problems associated with devices requiring a clinician to make unseen conduit connections to a port disposed within a subcutaneous pocket positioned beneath the skin. Those devices prevent the clinician from seeing the connection components while actuating and testing them, which could lead to improper or incomplete and unreliable connections that lead to device failure. In contrast, the present invention enables a clinician to easily place a conduit system  300  in a port  205  without requiring the clinician to blindly engage conduit connections to the port  205 , and this invention also provides means for easily and accurately determining where to trim the conduit for maximum safety, efficacy, and comfort to the patient. Additionally, the present invention enables the clinician to actuate and test a connection of a modular conduit system  300  in plain sight, outside of the subcutaneous pocket  32  and above the skin prior to final insertion of the conduit system  300  within the subcutaneous tunnel  42 . 
     While the present invention has been described above with reference to its preferred embodiments, it should be understood that various permutations of these embodiments can be readily devised by those skilled in the art without departing from the scope of the present invention. For instance, embodiments with multiple conduits could be employed, or conduits with multiple channels within them, without departing from the scope of this invention. One and two section conduit designs are presented as preferred embodiments, but some embodiments may require more than two conduit components without departing from the scope of this invention. The preferred embodiment of the two component conduit marking system also could be adapted to enable clinicians to trim multiple conduit components prior to assembly without departing from the spirit of this invention. 
     The sequence of steps for the placement procedure described above is generally suitable for placing different embodiments of this invention within a patient&#39;s vascular system. This invention clearly is suitable for use in other types of medical procedures that do not involve the vascular system and/or the skin that would require the clinician to employ other placement techniques and other, non-fluid carrying conduit, such as fiber optic cables, without departing from the spirit or scope of this invention. Also, the sequence of steps can be modified by those skilled in the art to still achieve the same final placement. Numerous adaptations to the preceding description can be readily devised by those skilled in the art without departing from the spirit and scope of the present invention as defined in the following claims.