Patent Publication Number: US-10773066-B2

Title: Implantable medical devices including septum-based indicators

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a division of U.S. patent application Ser. No. 14/587,862, filed on Dec. 31, 2014, now U.S. Pat. No. 10,052,471, which is a division of U.S. patent application Ser. No. 12/617,981, filed Nov. 13, 2009, now U.S. Pat. No. 8,932,271, which claims the benefit of U.S. Provisional Patent Application No. 61/114,331, filed Nov. 13, 2008, and titled “Septum-Based Indicators for an Implantable Medical Device,” each of which is incorporated herein by reference in its entirety. 
    
    
     BRIEF SUMMARY 
     Briefly summarized, embodiments of the present invention are directed to a medical device, such as an access port for providing subcutaneous access to a patient. The access port includes a septum including palpable identification indicia thereon. In particular, the access port in one embodiment includes a body that defines a fluid cavity and a needle-penetrable septum covering the fluid cavity for providing access thereto. The septum defines an outer periphery. 
     The palpable identification indicia of the septum are included as a plurality of raised palpation features. Each palpation feature includes a portion that extends in a radial direction beyond the outer periphery of the septum. The palpation features are therefore disposed relatively farther away from each other, simplifying palpation and identification thereof after the port has been subcutaneously implanted into a patient. The palpation features can be indicative of an attribute of the port, such as its ability to withstand fluid pressures and flow rates associated with power injection, for instance. 
     In other embodiments, the size, shape, number, and placement of the palpation features on the septum or other port surface can vary as appreciated by those skilled in the art. 
     These and other features of embodiments of the present invention will become more fully apparent from the following description and appended claims, or may be learned by the practice of embodiments of the invention as set forth hereinafter. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A more particular description of the present disclosure will be rendered by reference to specific embodiments thereof that are illustrated in the appended drawings. It is appreciated that these drawings depict only typical embodiments of the invention and are therefore not to be considered limiting of its scope. Example embodiments of the invention will be described and explained with additional specificity and detail through the use of the accompanying drawings in which: 
         FIG. 1A  is a perspective view of an implantable port including a septum configured according to one example embodiment; 
         FIG. 1B  is a top view of the port of  FIG. 1A ; 
         FIG. 2  is a cross sectional view of the port of  FIG. 1B , taken along the line  2 - 2 ; 
         FIG. 3  is a perspective view of the septum included in the port of  FIG. 1A ; 
         FIG. 4  is a cross sectional view of the septum of  FIG. 3 , taken along the line  4 - 4 ; 
         FIG. 5  is a top view of an implantable port including a septum configured according to one embodiment; 
         FIG. 6  is a top view of an implantable port including a septum configured according to one embodiment; 
         FIG. 7  is a top view of an implantable port including a septum configured according to one embodiment; 
         FIG. 8  is a top view of an implantable port including a septum configured according to one embodiment; 
         FIG. 9  is a top view of an implantable port including a septum configured according to one embodiment; 
         FIG. 10  is a top view of an implantable port including a septum configured according to one embodiment; 
         FIG. 11  is a top view of an implantable port including a septum configured according to one embodiment; 
         FIG. 12  is a top view of an implantable port including a septum configured according to one embodiment; 
         FIG. 13  is an exploded perspective view of an implantable port including a septum configured according to one embodiment; 
         FIG. 14  is a top view of an implantable port configured according to one embodiment; and 
         FIGS. 15A and 15B  are a top and side view, respectively, of an implantable port configured according to one embodiment. 
     
    
    
     DETAILED DESCRIPTION OF SELECTED EMBODIMENTS 
     Reference will now be made to figures wherein like structures will be provided with like reference designations. It is understood that the drawings are diagrammatic and schematic representations of exemplary embodiments of the present invention, and are neither limiting nor necessarily drawn to scale. 
       FIGS. 1A-15B  depict various features of embodiments of the present invention, which are generally directed to medical devices including ports, also referred to herein as access ports, for implantation into the body of a patient. In some situations, it can be desirable to facilitate access to the vasculature of a patient for purposes of blood withdrawal and/or infusions, such as when the patient is ill and may repeatedly undergo such procedures. In one implementation, vascular access is established via a catheter situated within a blood vessel of the patient. A port, subcutaneously implanted in the patient, is placed in fluid communication with the catheter. Accordingly, infusions and blood withdrawals may be made percutaneously via the port, rather than directly through the wall of a blood vessel. 
     Reference is first made to  FIGS. 1A-4 , wherein an implantable port  10  is disclosed as configured in accordance with one example embodiment. As shown, the port  10  includes a body, or housing  20 , which defines a fluid cavity  30  in communication with a rimmed opening, or aperture  34 , on an upper surface of the port. The housing  20  defines a passageway  40  in fluid communication with the fluid cavity  30  into which a stem  31  is disposed, wherein the stem is configured for coupling with a lumen of a catheter so as to provide fluid communication between the catheter and the fluid cavity. In another embodiment, the stem can be integrally formed with the housing. 
     In the present embodiment, the port  10  includes a septum  50 . The septum  50  is coupled with the housing  20  to cover the aperture  34  and the fluid cavity  30  defined by the housing, thus providing selective access to the fluid cavity. In the present embodiment, for example, the septum  50  includes an elastomeric material capable of being punctured by a needle, for example, a Huber needle, and substantially resealing upon removal of the needle. In one embodiment, the septum  50  includes silicone, though other materials can also be employed. In the illustrated embodiment, the port housing  20  includes a metallic material such as stainless steel or titanium, and the septum  50  is secured in place in the housing by a metallic retaining ring  24  that is press fit into the housing, as shown in  FIG. 2 . As will be seen below, the principles of the present disclosure can be employed with other port materials and configurations. These and other configurations are therefore contemplated. 
     The port  10  is configured to be implanted subcutaneously within a patient and operably connected to a catheter that, in turn, is disposed within a vein or other vessel. Accordingly, when the catheter is coupled with the stem  31  of the port  10 , fluid communication can be established with the vessel via the fluid cavity  30 , such as by an infusion needle inserted through the septum  50  of the port. A plurality of suture holes  42  can be included in the housing  20  so as to facilitate securement of the port  10  to the tissue of the patient when implanted. 
     The septum  50  in the present embodiment is defined by a body  52  including an upper body portion  52 A that is generally exposed through the aperture  34  of the port  10  and a lower body portion  52 B that is generally included within the interior of the port housing  20 . The upper body portion  52 A and lower body portion  52 B define a juncture  53 . The upper body portion  52 A includes a top surface  56  and an outer periphery  54 . Though the present embodiments deal particularly with the outer periphery  54 , i.e., a first outer periphery of the septum upper body portion  52 A, the lower body portion  52 B can be considered to define a second outer periphery including a relatively larger diameter than that of the first outer periphery. 
     In the present embodiment the periphery  54  of the upper body portion  52 A of the septum  50  is circular to match the circular aperture  34 , but in other embodiments it is appreciated that the outer periphery of the septum could define other shapes, including triangular, square, polygonal, other geometric shapes, etc. To the extent that the periphery of the septum defines other shapes, in some embodiments the shape of the aperture can also be modified to correspond in shape to that of the septum. 
     According to the present embodiment, a plurality of palpation features is included on the septum  50 . As shown in  FIGS. 1A-4 , the palpation features are included as three protrusions  60  that extend from a surface of the septum  50 . The three protrusions  60  are equidistantly spaced at substantially regular intervals around an outer portion of the septum  50  as to define end points, or vertices, of an imaginary triangle such as an equilateral triangle in the present embodiment. As best seen in  FIG. 1B , the protrusions  60  generally align with the vertices of the generally triangularly-shaped port housing  20 . The protrusions  60  extend upward from the generally flat septum top surface  56  such that the protrusions provide surface features to a top profile of the port  10  from the perspective shown in  FIG. 2 . 
     Note that, though three are used here, fewer or more palpable protrusions can be included on the septum top surface. Indeed, only one protrusion can be employed if desired. Also, though the port shown here is a port with a singular fluid cavity, multi-lumen ports including a plurality of fluid cavities and corresponding septa can include the palpation features discussed herein. The spacing, shape, and size of the palpation features can vary in a number of ways, some of which are described further below. 
     As best seen in  FIG. 1B , the protrusions  60  are shaped and positioned as to include a radially outward portion  62  that radially extends past the circular outer periphery  54  of the septum  50 . Thus, the radially outward portion  62  of each protrusion  60  extends beyond, or overlaps, the aperture  34  and thus extends over a portion of the retaining ring  24 . The radially outward portion  62  of each protrusion  60  includes a bottom surface  55  extending angularly away from the upper body portion  52 A of the septum  50 , as shown in  FIG. 4 . 
     The overlapping aspect of the protrusions  60  causes a center point of each protrusion to be disposed relatively farther away from the other protrusions than if the protrusions were confined within the bounds defined by the septum outer periphery  54 . This in turn enables the protrusions to be more easily palpated and identified by a clinician performing the palpation for an implanted port than if the protrusions were closer set. Thus, the tactile acuity of the clinician palpating the port  10  is preserved without increasing the size of either the septum or its protrusions. Desire for increased tactile acuity has increased in recent years in light of the trend toward a reduction in size of manufactured ports, and by extension, septum size. 
     In greater detail,  FIG. 4  shows one of the protrusions  60  of the septum  50  in cross section, wherein a notch  64  is defined by virtue of the overlapping nature of the protrusion. The notch  64  enables the protrusion to extend over the edge of the aperture  34 , defined in this embodiment by the retaining ring  24 , without interfering with the retaining ring. Of course, the size and shape of the notch and protrusion can be modified to adapt to a particular port configuration. 
     The protrusions  60  in the present embodiment are oblong-shaped, generally resembling a seed or tear drop shape, and include a smoothly contoured surface, as best seen in  FIGS. 1B and 3 . The smooth contour of the protrusions  60  assists in reducing tissue irritation when the port  10  is implanted in the patient. In the present embodiment where the septum  50  generally defines a disc-like shape including an outer periphery diameter of about 0.42 inch (indicated at X 1  on  FIG. 4 ), the protrusions  60  axially extend a distance of about 0.046 inch above the top surface  56  of the septum body  52  (indicated at Y on  FIG. 4 ) and about 0.055 inch radially beyond the periphery  54  (indicated at X 2  on  FIG. 4 ), though other size dimensions are of course possible. The protrusions  60  are integrally formed with the septum  50  in the present embodiment, but could be separately formed and attached to the septum in another embodiment. Note that the shapes of the protrusions can be shaped in other ways, as will be seen further below. Note further that each protrusion on the septum can include a different shape with respect to the other protrusions, if desired. 
     In one embodiment, the palpation features, i.e., protrusions  60  of the septum  50 , can permit a clinician to properly identify a predetermined attribute or characteristic of the port  10 . The attribute of the port  10  in one embodiment is the suitability of the port to withstand relatively high fluid flow and/or fluid pressure rates therethrough, commonly referred to as “power injection.” Such high pressure and flow rates are typically associated with power injection of fluids through the port during relatively demanding procedures (e.g., computed tomography, or “CT,” scans), in which contrast media is rapidly infused through the port and connected catheter and into a vascular system. For instance, in one embodiment power injection includes fluid infusion by a power injection machine producing fluid pressures of up to about 325 psi, resulting in fluid pressures in the port  10  between about 50 and about 90 psi and fluid flow through the port at a rate between about two and about five milliliters per second. Other flow rates and fluid pressures are, of course, possible. 
     During power injection, a needle can be inserted in a septum of the port and connected to a power injection machine, which can introduce contrast media through the port at a relatively high flow rate, as detailed above. Certain ports may not be able to withstand pressures corresponding to high flow rates during power injection. Accordingly, it is often necessary to determine whether an implanted port is compatible for power injection. 
     The protrusions  60  enable identification of a port as power injectable, in one embodiment. In particular, after subcutaneous implantation of the port  10  in a patient, a clinician cannot visually observe the port to determine whether it is suitable for power injection. With a port  10  configured as shown in  FIGS. 1A-4 , the clinician can feel or palpate the three protrusions  60  through the skin to determine that the port is suitable for power injection. In addition, other information regarding the port  10  can be gathered by palpation, including the general orientation of the port, location the septum  50 , etc. 
     In addition to its suitability for power injection, in other embodiments other predetermined attributes or characteristics of the port can be indicated by the protrusions described herein. Such attributes include, for example, the type of catheter to which the port is connected, e.g., whether the catheter distal tip is open-ended or includes distal valve, the type of material from which the port is constructed, etc. Such ability to determine the predetermined characteristic(s) of the port is useful for ports of all types, including those made from radio-translucent materials, which are not sufficiently imaged radiographically. 
     As already described, the protrusions  60  in  FIGS. 1A-4  are tear drop-shaped to provide a smooth contour surface and to avoid irritating body tissue proximate the port implanted location. In other embodiments, though, the shape, size, number, and placement of the palpation features can be modified from what is explicitly shown and described herein in order to suit a particular need.  FIGS. 5-12  give several examples of different possible protrusion configurations for the septum  50  of the port  10 .  FIG. 5  shows overlapping protrusions  160  defining a flat cylindrical shape.  FIG. 6  depicts protrusions  260  defining flat cylindrical shapes similar to those shown in  FIG. 5 , wherein the protrusions  260  overlap the aperture  34  a relatively more than the protrusions  160  of  FIG. 5 . 
       FIGS. 7 and 8  depict protrusions  360  and  460  that define oblong and roughly conical shapes, respectively, while  FIGS. 9 and 10  respectively depict semi-spherical protrusions  560  and  660 .  FIGS. 11 and 12  show relatively thin protrusions  760  and  860  disposed with their long axes extending tangentially to the septum outer periphery  54 . Note that the outer periphery  54  of the septum  50  in  FIG. 12  generally defines a triangular shape. 
     As described above, the principles of the present disclosure can be applied to ports from a variety of materials.  FIG. 13  gives one example of this, wherein a port  1010  is shown including a cap  1014  and a base  1016 , both formed from an engineering plastic material, such as Polyoxymethylene (“POM”), also known as an acetal resin, or other suitable material. The septum  50  including the protrusions  60  is sandwiched between the cap  1014  and base  1016  so as to be captured therebetween when the cap and base are mated together and such that the protrusions overlap past an aperture  1034  defined by the cap  1014 . Note that in the illustrated embodiment, four overlapping protrusions are included on the septum  50 , in contrast to embodiments described earlier. Suture plugs  1022  and a stem  1031  are also included with the port  1010 . 
     Palpation features can be included on the port in other configurations, as shown in  FIGS. 14-15B . In  FIG. 14 , a plurality of protrusions  962  is included on the housing  20  of the port  10 . The protrusions  962  can be hard or resilient and are spaced so as to enable palpation of the port  10  when subcutaneously implanted. The protrusions  962  can be adhered to the port housing surface  20  via an adhesive, can be inserted into corresponding holes defined in the housing, or can be included in other suitable ways. Note that, as before, the size, shape, number, and configuration of the protrusions can vary from what is explicitly shown here. 
       FIGS. 15A and 15B  show a plurality of protrusions  1062  inserted into the suture holes  42  of the port housing  20 . The protrusions  1062  are resilient and extend a predetermined distance above a top surface of the port  10  so as to enable palpation thereof when the port is implanted. The protrusions  1062  are inserted and secured in the suture holes  42  via a friction fit, mechanical capture, or other suitable method. Of course, the number, size, position, and shape of both the suture holes and corresponding protrusions can vary from what is explicitly described herein. 
     The number, size, position, and shape of the palpation features can be modified while residing within the scope of embodiments of the present invention. In addition to the above embodiments, it is appreciated, for example, that the protrusions can define patterns other than equilateral triangles, including acute triangles, obtuse triangles, squares, etc. Additionally, one, two, three, four, five, or more protrusions could be used. In one embodiment, the port includes two or more septa with protrusions extending from each. The protrusions can define a variety of different shapes, and may be sized differently. Indeed, the protrusions can include configurations such as those shown and described in U.S. Pat. No. 8,177,762, which is incorporated herein by reference in its entirety. Thus, the foregoing examples are merely illustrative in nature. 
     Embodiments of the invention may be embodied in other specific forms without departing from the spirit of the present disclosure. The described embodiments are to be considered in all respects only as illustrative, not restrictive. The scope of the embodiments is, therefore, indicated by the appended claims rather than by the foregoing description. All changes that come within the meaning and range of equivalency of the claims are to be embraced within their scope.