Abstract:
A device for providing access to an implantable fluid transfer port, comprises a needle extending to a distal end insertable into body to enter a reservoir of a port implanted therein and an actuation member extending through a lumen of the needle from an actuator which remains external to a living body accessible to a user thereof in combination with an obturator coupled to a distal end of the actuation member, an outer diameter of the obturator substantially matching an inner diameter of the lumen of the needle so that, when retracted into the lumen, the obturator seals a distal opening thereof and an anchoring mechanism coupled to the actuation member proximally of the obturator, the anchoring mechanism being moved to an expanded state in which an outer diameter of the anchoring mechanism exceeds an outer diameter of the needle when moved out of the lumen of the needle.

Description:
PRIORITY CLAIM 
       [0001]    This application claims priority to U.S. Provisional Application Ser. No. 60/972,178 entitled “Apparatus and Methods for Injecting Fluid Through Subcutaneous Port,” filed Sep. 13, 2007. The entire disclosure of the above-identified application is incorporated by reference into this application. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates generally to apparatus and methods for delivering fluids to subcutaneous locations and more particularly, to apparatus and methods for injecting fluids through subcutaneous ports. 
       BACKGROUND INFORMATION 
       [0003]    Central venous system access is required for the long-term administration of fluids to (e.g., drugs, therapeutic agents, chemotherapy agents) and to draw blood or other fluids from a patient. For example, many medical procedures require that a patient receive an infusion that last for hours or even days. Infusions may also need to be repeated periodically over a period of months or years. Such long term access to the venous system is often obtained via a subcutaneous access port. Subcutaneous port systems often include an aperture sealed with a self-sealing septum for receiving a needle and an outlet connection leading to a transfer device, such as an implanted cannula or catheter, which may be fed into a vein or artery. A reservoir receiving the infused or withdrawn fluids is situated between the septum and the outlet connection. The subcutaneous port is accessed by inserting the needle through the skin of the patient and through the septum into the reservoir. A fluid may then be then injected through the needle into the reservoir or withdrawn from the body into the needle as would be understood by those skilled in the art. 
         [0004]    Multiple punctures applied to the septum over the long-term period of use may cause the septum to wear out and thus be unable to provide a fluid tight seal to the reservoir. Thus, fluids may leak from the reservoir and into the surrounding tissue, thus causing potential harm thereto. Additionally, long-term use of the septum may cause a needle used therewith to core out or dislodge small particles of the seal with each penetration, thus creating a permanent channel through the septum over an extended period. Still further, a needle may be prematurely removed from the septum under power injection treatment. In each case, harmful or painful agent may be injected under the patient&#39;s skin. 
       SUMMARY OF THE INVENTION 
       [0005]    A device for providing access to an implantable fluid port, comprises a needle extending from a proximal end located external to a living body to a distal end insertable into a reservoir of the implantable port via a septum provided thereover, wherein a cannula extends through the needle from a proximal end open to an inlet port to a distal opening. A probe is slidably disposed within the cannula, the probe having an elongated probe shaft and further comprising an obturator located at a distal end of the probe shaft, wherein an outer diameter of a portion of the obturator is sufficient to seal the distal opening of the cannula and an expanding anchoring mechanism located along a distal length of the probe shaft. The needle is movable between an insertion configuration where the obturator seals the distal opening of the cannula and an expanded configuration wherein the obturator is moved distally so that the anchoring mechanism is moved distally of the distal end of the needle, wherein distal movement of the probe causes the anchoring mechanism to move to the are deployed distally of a distal opening of the needle. 
         [0006]    The present invention is directed to a device for providing access to an implantable fluid transfer port, comprising a needle extending to a distal end insertable into a living body to enter a reservoir of a port implanted therein and an actuation member extending through a lumen of the needle from an actuator which remains external to a living body accessible to a user thereof in combination with an obturator coupled to a distal end of the actuation member, an outer diameter of the obturator substantially matching an inner diameter of the lumen of the needle so that, when retracted into the lumen, the obturator seals a distal opening thereof and an anchoring mechanism coupled to the actuation member proximally of the obturator, the anchoring mechanism being moved to an expanded state in which an outer diameter of the anchoring mechanism exceeds an outer diameter of the needle when moved out of the lumen of the needle. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0007]      FIG. 1  is a plan view of a medical system for delivering fluid to a patient according to an exemplary embodiment of the present invention; 
           [0008]      FIG. 2  shows a top view of a subcutaneous port of the system of  FIG. 1 ; 
           [0009]      FIG. 3  shows a partial cross-sectional view of the subcutaneous port of  FIG. 2  taken along the line  3 - 3 ; 
           [0010]      FIG. 4A  shows a first side view of an exemplary needle according to the present invention in a first retracted configuration; 
           [0011]      FIG. 4B  shows a second side view of the needle of  FIG. 4A  in a deployed configuration; 
           [0012]      FIG. 4C  shows a cross sectional view of the needle  FIGS. 4A and 4B , taken along the line  4 C- 4 C; 
           [0013]      FIG. 5A  shows a partial cut-through view of a system according to the present invention in a retracted configuration in a subcutaneous port; 
           [0014]      FIG. 5B  shows a partial cut-through view of the system of  FIG. 5A  in a deployed configuration; 
           [0015]      FIG. 5C  shows a partial cut-through view of the system of  FIG. 5A  once returned to the retracted configuration; and 
           [0016]      FIG. 5D  shows the system of  FIG. 5A  with the needle removed from the subcutaneous port. 
       
    
    
     DETAILED DESCRIPTION 
       [0017]    The present invention may be further understood with reference to the following description and to the appended drawings, wherein like elements are referred to with the same reference numerals. The present invention relates to devices for providing long-term access to subcutaneously implanted access ports for infusing or withdrawing fluids from a living body. Specifically, a system and method according to the present invention seeks to minimize damage to a septum of a subcutaneous port with long-term use. It is noted that, although embodiment of the present invention are directed to septa of subcutaneous ports, the present invention may be employed in any port that utilizes a septum over an inlet port thereof. 
         [0018]    A system according to the present invention comprises an implantable fluid transfer assembly and a fluid injection needle. The fluid transfer assembly comprises a reservoir for into which fluids may be injected and/or into which fluids may be drawn from the body before entering the needle. The assembly also includes an outlet port in fluid communication with the reservoir and an inlet port with a self-sealing septum in fluid communication with the reservoir. In one embodiment, the fluid transfer assembly comprises a subcutaneous port that carries the reservoir, inlet port, and outlet port, and a catheter in fluid communication with the outlet port of the subcutaneous port. The fluid injection needle comprises a cannula formed as an elongated shaft with a lumen extending therethrough and a distal outlet port and an inner probe slidably disposed within the lumen of the cannula. In one embodiment, the cannula has a fluid infusion port in fluid communication with the cannula lumen, and the medical system further comprises a pump in fluid communication with the fluid infusion port. The inner probe includes an elongated shaft, an obturator carried on an inner probe shaft thereof and a self-expanding anchoring mechanism carried by the inner probe shaft. In one embodiment, the self-anchoring mechanism is a resilient basket structure. In another embodiment, the obturator is disposed distal to the anchoring mechanism and comprises a cylindrical member and an obturator tip (e.g., a spherically-shaped tip). The fluid injection needle is configured to be moved between an insertion/removal state with the anchoring mechanism retracted within the cannula lumen and the obturator seated within the outlet port of the cannula lumen, and a fluid delivery/withdrawal state with the obturator and anchoring mechanism deployed from the cannula shaft. 
         [0019]    As shown in  FIG. 1 , an implantable fluid transfer system  10  according to the invention comprises an implantable fluid transfer assembly  25  including a subcutaneous port  12  and a catheter  14  in fluid communication with the subcutaneous port  12  for periodically administering fluids (e.g., for nutrition, hydration, drugs and/or other therapeutic agents, etc.) to or withdrawing fluids from a designated vessel (e.g., a blood vessel). The fluid transfer system  10  further comprises an external fluid transfer apparatus  70  for delivering fluids (e.g., therapeutic agents) to the vessel and/or withdrawing fluids therefrom via the implantable fluid transfer assembly  25 , and in particular, into the subcutaneous port  12  thereof. As described above, fluids travel between the vessel and the external fluid transfer apparatus  70  via the catheter  14 , the subcutaneous port  12  and a needle  52  of the external fluid transfer apparatus  70 . As indicated above, the therapeutic agent may comprise hydrating fluids, nutrition, drugs, biologics, proteins, genetic materials, or any other substance or material which medical personnel may prescribe as beneficial for the patient, as those skilled in the art will understand. 
         [0020]    As known to those skilled in the art, the subcutaneous port  12  may be implanted, for example, just below a target portion of the skin  15  adjacent a in an area selected for its ease of access and/or proximity to a targeted blood vessel, etc. and the catheter  14  is subcutaneously tunneled to the targeted blood vessel. The external fluid transfer apparatus  70  may be employed to supply fluids to the subcutaneous port  12  in accordance with a method explained in detail hereinafter. The external fluid transfer apparatus  70  generally comprises a needle  52  connected to an external power injection pump  72  via a tube  92  formed of a material selected as would be understood by those skilled in the art to be suitably flexible and resilient to enable it to operate during high-pressure power injections. The subcutaneous port  12  of the present invention is also suitable for use at the relatively high pressures associated with power injections induced by the external fluid transfer apparatus  70  without leakage or failure. Moreover, the subcutaneous port  12  is suitable for repeated use at the pressures induced by the external fluid transfer apparatus  70 . In one aspect, for example, the subcutaneous port  12  is suitable to withstand the pressure of at least approximately 300 psi generated by the external power injection pump  72  without leakage or failure. 
         [0021]    The external fluid transfer apparatus  70  may be operated over a wide variety of flow rates and working pressures. In the illustrated embodiment, the external fluid transfer apparatus  70  injects fluid into the subcutaneous port  12  at a flow rate equal to or greater than 5 cc/sec. It is noted that, although embodiments of the present invention are described with respect to a high pressure external fluid transfer apparatus  70 , any commercially available power injection apparatus, such as rotary pumps, in-line pumps and gear pumps, is suitable for use with the system  10  of the present invention. Furthermore, in an alternate embodiment, a manually actuated injector pump (not shown) may be used in place of the power injection pump  72 . 
         [0022]    As shown in  FIGS. 2 and 3 , the subcutaneous port  12  of the present invention comprises a housing  31  formed of a biocompatible material, such as stainless steel or a titanium alloy, and is of a size and shape that facilitates implantation thereof under the skin  15  of the patient. In an exemplary embodiment, the shape of the subcutaneous port  12  comprises a relatively flat housing  31  having rounded corners to avoid undue trauma to adjacent tissue when implanted in situ much like existing implantable pacemakers or cochlear stimulators. The subcutaneous port  12  further comprises a reservoir  30  for housing a therapeutic agent therein. At a distal end, the reservoir  30  is in fluid communication with an outlet port  39  which is in further fluid communication with the catheter  14  connected to a blood vessel of the patient. The catheter  14  includes an adapter  16  that can be releasably mated with the outlet port  39  of the subcutaneous port  12 . As shown in greater detail in  FIG. 3 , the housing  31  of the subcutaneous port  12  comprises a threaded female portion  40  located adjacent to the outlet port  39 . A respectively threaded male portion  41  of the adapter  16  is sized and shaped to permit alignment of the outlet port  39  with the catheter  14  when the threaded male portion  41  is screwed in the female portion  40 . In this manner, a fluid-tight engagement is forged between the subcutaneous port  12  and the catheter  14 . 
         [0023]    At a proximal end, the reservoir  30  is open to an inlet port  42  with a self-sealing septum  43  formed thereover. The septum  43  is formed as a substantially circular member with an annular septum recess  47  formed along an outer perimeter thereof. It is noted, however, that the septum  43  may assume any shape known in the art such as, for example, a rectangle, wherein a shape of the housing may be chosen to accommodate the shape of the septum  43 . Furthermore, the septum  43  may be formed of a material suitable for subcutaneous implantation, as known to those of skill in the art. The septum  43  is fluidly sealed against the inlet port  42  to prevent a leakage of fluid from a perimeter thereof. Specifically, the septum  43  is seated within an annular recess  44  formed in a proximal face of the housing  31 . An annular collar  45  is then formed over the housing  31 , the annular collar  45  abutting the annular septum recess  47  and thus retaining a configuration of the septum  43 . The annular collar  45  may be formed of a shape and size to circumferentially abut the outer surface area of the housing  31  and may be held in place using a means known in the art. 
         [0024]    Referring to  FIGS. 4A-4C , the needle  52  includes an elongated cannula  54  extending distally out of a handle assembly  82 . The cannula  54  includes an elongate shaft  58  extending from a proximal end  60  adjacent the handle assembly  82  to a distal end  62  comprising a tissue penetrating tip  68 , which allows the needle  52  to be more easily introduced through tissue while minimizing tissue trauma. A lumen  64 , shown in greater detail in  FIG. 4C  extends through the length of the shaft  58  to a distal opening  53 . The lumen  64  is sized and shaped to slidably receive a probe  56  therein while remaining in fluid communication with the distal opening  53 . As will be described in greater detail below, the probe aids in preventing coring of the septum  43  while serving to anchor the needle  52  in place in the reservoir  30 . In this manner, fluids may be infused or withdrawn from the reservoir  30  into which the distal end  62  is open while the probe is inserted therein. In an alternate embodiment, the cannula  54  may be formed with dual-lumens to maintain separate channels for each of the probe  56  and the fluids to be delivered and/or withdrawn. 
         [0025]    The shaft  58  of the cannula  54  may be composed of any material known in the art as suitable for forming needles for power injection. For example, the shaft  58  may be formed of any known suitable substantially rigid, metal or plastic material, such as, for example, stainless steel. The shaft  58  will have a length similar to that of known power injection needles. For example, the shaft  58  may typically have a length in the range from 5 cm to 30 cm, and more preferably, from 10 cm to 25 cm. An outer diameter of the shaft  58  is consistent with its intended use as a non-coring needle and is preferably in the range of 0.7 mm to 5 mm, and, more preferably, from 1 mm to 4 mm. 
         [0026]    The probe  56  is slidably disposed within the lumen  64  and comprises a probe shaft  79  extending from a proximal end  76  thereof to a distal end  78  comprising a non-coring obturator  85 . A self-expanding anchoring mechanism  80  is coupled to the probe shaft  79  proximally of the obturator  85  and substantially adjacent thereto. The probe shaft  79  may, for example, be formed of a suitably rigid material, so that it has the required axial strength to slide within the lumen  64  and move the obturator  85  and the anchoring mechanism  80  into and out of the shaft  58 . In an exemplary embodiment, the probe shaft  79  is composed of stainless steel. 
         [0027]    The obturator  85  is sized and shaped to facilitate the anti-coring properties of the needle  52 . In particular, the obturator  85  includes a spherical tip coupled to the probe shaft  79 . The obturator  85  generally may be formed, for example, of any suitable substantially rigid, metal or plastic as those skilled in the art will understand. The obturator  85  is preferably sized to be slidably received in and to closely fit the lumen  64  so that it may be slid in and out of the lumen  64  and so that, when received therewithin, it substantially seals the lumen  64  minimizing coring of the septum  43   
         [0028]    The self-expanding anchoring mechanism  80  in this mechanism comprises a resilient basket structure including an array of individual splines  81 , opposite ends of which are connected to the distal end  78  of the probe shaft  79 . Each of the individual splines  81  comprises, for example, a spring wire formed from a metal having a suitable shape memory, such as stainless steel, nickel-titanium alloys, spring steel alloys, and the like. Alternatively, the splines  81  may be formed from other material that will retain a memorized shape as known to those of skill in the art. The curved proximal ends of the splines  81  are shaped so that they will assume a radially constrained configuration as they are drawn into the lumen  64  of the cannula  54  and will return to the memorized radially divergent configuration when axially extended from the cannula  54 . 
         [0029]    The handle assembly  82  comprises a handle member  84  mounted to the proximal end  76  of the probe shaft  79 , and a handle sleeve  86  mounted to the proximal end  60  of the cannula  54 . The handle member  84  is slidably engaged with the handle sleeve  86  (and the cannula  54 ). The handle member  84  and handle sleeve  86  can be composed of any suitable rigid material, such as, e.g., metal, plastic, or the like. The handle assembly  82  also includes an infusion port  88  mounted within the handle sleeve  86 . The infusion port  88  is in fluid communication with the lumen  64  via a handle sleeve lumen (not shown) formed in the handle sleeve  86  and is sized and shaped to mate with a distal end of the tube  92  of the power injection pump  72 . The handle sleeve lumen (not shown) may also include a valve (not shown) for maintaining a fluid-tight seal of the handle sleeve lumen. 
         [0030]    It may be readily appreciated that longitudinal translation of the probe  56  relative to the cannula  54  in a proximal direction  93  can be achieved by holding the handle sleeve  86  and displacing the handle member  84  in the proximal direction  93 , thereby retracting the anchoring mechanism  80  into the distal end  62  of the cannula  54  and thus retracting the spherical tip  89  of the obturator  85  proximally to seal the outlet port  53  ( FIG. 4A ). The retracting of the obturator tip  89  and the anchoring mechanism  80  configures the fluid injection needle  52  into an insertion/removal state. Because the splines  81  are formed of spring steel, they may be drawn within the cannula  54 , during percutaneous insertion. 
         [0031]    In contrast, longitudinal translation of the probe  56  relative to the cannula  54  in a distal direction  91  can be achieved by holding the handle sleeve  86  and displacing the handle member  84  in the distal direction  91 , thereby deploying the obturator  85  and the self-expanding anchoring mechanism  80  from the distal end  62  of the cannula shaft  58  ( FIG. 4B ). The deployment of the obturator  85  and the self-expanding anchoring mechanism  80  from the distal end  62  configures the fluid injection needle  52  into the fluid delivery/withdrawal state. The deploying of the anchoring mechanism  80  distally from the cannula  54  frees the anchoring mechanism  80  to assume its radially divergent shape. 
         [0032]    Referring now to  FIG. 5A-5D , a method of injecting a medication or fluid into the subcutaneous port  12  using the fluid injection needle  52  is shown. First, the septum  43  of the subcutaneous port  12  is located beneath the skin  15  of a patient, e.g., by pushing with a finger or other device, and as shown in  FIG. 5A , the injection needle  52  is inserted through the skin  15  and through the septum  43  of the inlet port  42 , so that a distal end  62  of the needle  52  lies at or within the reservoir  30 . The injection needle  52  is inserted through the septum  43  while the needle  52  is in the insertion/removal state; that is, the obturator  85  is located within distal end  62  of the cannula  54  with the spherical tip of the obturator  85  seated within the outlet port  53 . Significantly, the spherical tip of the obturator  85 , when seated within the outlet port  53 , prevents the outlet port  53  of the cannula  54  from coring the septum  43 . 
         [0033]    As shown in  FIG. 5B , the injection needle  52  is then placed into its fluid delivery/withdrawal state by deploying the obturator  85  and the anchoring mechanism  80  distally from the distal end  62  of the cannula  54  by advancing probe  56  in the direction of arrow  91 ; that is, by holding the handle sleeve  86  and displacing the handle member  84  in the distal direction  91 . The anchoring mechanism  80  is advanced so that the expanding splines  81  of the resilient basket structure abut an inner surface  46  of the septum  43 , thereby stabilizing the injection needle  52  relative to the subcutaneous port  12 . Next, a specified amount of the medication is injected into the reservoir  30  by the power injection pump  72  (shown in  FIG. 1 ) through the injection needle  52 , which medication flows through the catheter  14  via the outlet port under pressure and into the venous system. 
         [0034]    When delivery of the medication has been completed, the injection needle  52  is placed into its insertion/removal state by retracting the anchoring device  80  and obturator  85  within the needle cannula  54  in the direction of arrow  93 ; that is, by holding the handle sleeve  86  and displacing the handle member  84  in the proximal direction  93 , as shown in  FIG. 5C . Then, the injection needle  52  is withdrawn from the patient, and as shown in  FIG. 5D , the septum  43  of the subcutaneous port  12  is left intact. 
         [0035]    It may be appreciated that, while the use of the fluid injection needle  52  lends itself well to the delivery of fluid through an implanted subcutaneous port, the fluid injection needle  52  may be used to deliver fluid to other types of implantable devices. For example, the needle  52  can be used to refill the reservoir of a drug pump. 
         [0036]    Although particular embodiments of the present invention have been shown and described, it will be understood that it is not intended to limit the present invention to the preferred embodiments, and it will be obvious to those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the present invention. Thus, the present inventions are intended to cover alternatives, modifications, and equivalents, which may be included within the spirit and scope of the present invention as defined by the claims.