Abstract:
An injection port for subcutaneous placement within a body. The injection port includes an elongated flexible substantially non-rigid body having first and second ends and a wall therebetween. The wall is made from one or more materials such that it will self seal after being punctured by a needle. The body of the device further includs and a fluid reservoir surrounded by the wall. Lastly, the injection port includes a flexible elongated tubular catheter attached to the body which is in fluid communication with the reservoir.

Description:
FIELD OF THE INVENTION  
       [0001]     This invention relates generally to the field of medicine, and more specifically to medical devices that are surgically implanted in a patient, and is particularly relevant to implantable injection or infusion ports such as used for chemotherapy and adjustable gastric band procedures.  
       BACKGROUND  
       [0002]     Surgeons routinely implant subcutaneous injection ports in patients requiring long term, periodic fluid injections such as for chemotherapy and gastric band adjustments. The injection port connects to a flexible tube catheter to transport the fluid to the affected area (subclavian vein, etc.) or the gastric band. Current injection ports comprise a rigid metal or plastic housing, which is about 25 mm in diameter and 15 mm tall. A thick, silicone septum captured within the rigid housing covers an inner chamber that fluidly communicates with the catheter. The surgeon uses a hypodermic needle to inject fluid into the chamber through the silicone septum.  
         [0003]     Typically the surgeon fastens the injection port with suture to fascia and beneath the fat and skin layers, primarily to prevent the port from flipping over, but also to prevent the injection port from migrating in the body. Since the septum is accessible from only one side of the injection port, flipping over requires interventional surgery to right the port for subsequent injections.  
         [0004]     For some patients, the surgeon may place the injection port in the lower abdomen, thus burying the port beneath a fat layer that may be several centimeters thick. Usually a surgeon can locate the port with palpation alone. However, if there is a very thick, intervening fat layer, such as on extremely obese, gastric band patients, the surgeon must also use fluoroscopy, ultrasound, or other means to locate the port. Furthermore, the surgeon must inject the needle in a direction approximately perpendicular to the injection port, and hit the target area of the septum, which is only about 12-15 mm in diameter. For some patients, the surgeon may place the injection port on the sternum or upper right chest, just beneath the skin layers. Although easy to locate with palpation, some patients regard the protruding port as uncomfortable or cosmetically objectionable.  
         [0005]     What is needed, therefore, is a subcutaneously implantable injection port that is made of relatively soft and flexible materials, and ideally, that looks and feels more (than current injection ports) like a large, natural blood vessel. What is also needed is a subcutaneously implantable injection port that is penetrable with a hypodermic needle, independent of the orientation of the injection port in bodily tissue, and that is self-sealing when the needle is removed. What is further needed is a subcutaneously implantable injection port that a surgeon may position in the body more quickly and with less dissection than is required for conventional injection ports.  
       SUMMARY OF THE INVENTION  
       [0006]     An injection port for subcutaneous placement within a body. The injection port includes an elongated flexible substantially non-rigid body having first and second ends and a wall therebetween. The wall is made from one or more materials such that it will self seal after being punctured by a needle. The body of the device further includs and a fluid reservoir surrounded by the wall. Lastly, the injection port includes a flexible elongated tubular catheter attached to the body which is in fluid communication with the reservoir. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0007]     We present the specific, novel features of this invention in the appended claims. The reader may best understand, however, the organization and methods of operation of this invention by referring to the detailed description and the following drawings:  
         [0008]      FIG. 1  is an isometric view of an injection port of the prior art;  
         [0009]      FIG. 2  is a cross sectional view of the injection port of the prior art shown in  FIG. 1 ;  
         [0010]      FIG. 3  is an isometric view of a first embodiment of a flexible injection port  30 ;  
         [0011]      FIG. 4  is a sectional view of flexible injection port  30  shown in  FIG. 3 ;  
         [0012]      FIG. 5  is an enlarged, longitudinal sectional view of flexible injection port  30  penetrated by a hypodermic needle  100 ;  
         [0013]      FIG. 6  is a cross sectional view of a second embodiment of a flexible injection port  50 ;  
         [0014]      FIG. 7  is a cross sectional view of a third embodiment of a flexible injection port  60 ;  
         [0015]      FIG. 8  is an isometric view of a fourth embodiment of a flexible injection port  80 ;  
         [0016]      FIG. 9  is a cross sectional view of flexible injection port  80 ;  
         [0017]      FIG. 10  shows injection port  30  subcutaneously implanted near a fascia layer  124  in a patient;  
         [0018]      FIG. 11  shows injection port  30  subcutaneously implanted near a skin layer  120  in a patient; and  
         [0019]      FIG. 12  shows injection port  30  subcutaneously implanted in a fat layer  122  in a patient. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0020]     Referring now to the drawings,  FIGS. 1 and 2  show an injection port  10  of the prior art. Injection port  10  generally has a truncated, conical configuration, and comprises a body portion  12 , a housing  14 , a seal element  16 , and a catheter element  18 . The body portion  12  is made of a flexible, rubberized material with a cavity  20  formed inside. A catheter support  22  integrally forms in body portion  12 . Housing  14  is made of a corrosion resistant metal, and has a reduced, upwardly facing entry passage  24 . Seal element  16  is made of a rubberized material, which is easily penetrable by a hypodermic needle or the like, and provides a penetrable seal for passage  24 . Housing  14  and seal element  16  define an open cavity  20  in injection port  10  for receiving and containing a fluid. Catheter element  18  extends through catheter support  22  of body portion  12  and through housing  14  so that catheter element  18  extends into cavity  20  for providing communication between cavity  20  and the exterior of injection port  10  for dispensing fluid from the cavity  20  into the body of a patient.  
         [0021]     A surgeon implants injection port  10  subcutaneously in a patient. To introduce a fluid such as a medication or a saline solution, the surgeon inserts a hypodermic needle or the like into the patient so that the tip of the needle passes through seal element  16  and into cavity  20 . Due to the relatively small size of passage  24 , each time the surgeon introduces a fluid into the patient, the surgeon must insert the needle through seal element  16  and the same localized area of the skin and tissue of the patient. Accordingly, seal element  16  may become significantly damaged and eventually develop a leak. Also, the localized skin area and underlying tissue may not heal in the desired manner. Further, because housing  14  is made of metal, it can cause barbing of the needle tip, causing increased trauma to the patient upon withdrawal of the needle. Still further, because of the truncated conical configuration of injection port  10  and the metallic construction of housing  14 , injection port  10  can cause substantial discomfort to a patient, particularly if the area of the patient adjacent the injection port is accidentally bumped or bruised. In addition, because of the truncated conical configuration of injection port  10 , it can cause a relatively unattractive mound on the body of a patient. Still further, since fluid can only be introduced in cavity  20  through passage  24 , a surgeon must insert a needle into injection port  10  in substantially perpendicular relation to the skin so that often the adjacent area of tissue or skin of the patient cannot effectively support the needle.  
         [0022]     When using injection port  10  of the prior art in a laparoscopic procedure such as implantation of a gastric band, it is necessary for the surgeon to assemble injection port  10  to catheter element  18  during the laparoscopic procedure. This is because injection port  10  is too large to pass through a standard size (12 mm diameter) laparoscopic port, which is used for access to the stomach inside the abdominal cavity. The surgeon must introduce the gastric band and the catheter into the abdominal cavity without the injection port attached to the free end of the catheter. Once the surgeon has secured the gastric band around the stomach, the surgeon externalizes the free end of the catheter through the abdominal muscle and fascia layers, subcutaneous fat layer, and the skin to assemble the injection port to the free end of the catheter. Then the surgeon implants the injection port subcutaneously at the desired location on the patient&#39;s abdomen or chest. The surgeon must take extra time to assemble the injection port to the catheter. Also, the surgeon must skillfully connect the injection port to the catheter during less than ideal conditions. Consequently, there is the potential complication of an undiscovered leak developing at the connection of the catheter to the port.  
         [0023]      FIG. 3  is an isometric view of a first embodiment of the present invention showing a flexible injection port or body  30 , that generally comprises a first end  34 , a second end  36 , and a cylindrical injection portion  32  extending there between. A surgeon may use a hypodermic needle or the like to penetrate injection portion  32  and introduce a fluid such as a medication or saline solution into flexible injection port  30 . Injection portion  32  self-seals when the surgeon removes the hypodermic needle. Injection portion  32  may have a length, but is not limited to, approximately 5-20 cm. Injection portion  32  may have a diameter, but is not limited to, approximately 5-12 mm. A catheter  42  attaches to first end  34  and distributes fluid injected into flexible injection port  30  to another portion of the patient&#39;s body. Catheter  42  is made from a silicone rubber or other biocompatible polymer such as known in the art for application to conventional injection ports, such as shown in  FIGS. 1 and 2 . A tether  38  having an eye loop  40  extends from second end  36 . A surgeon may use a conventional surgical grasping instrument to grasp tether  38 , or a surgical suture tied to eye loop  40 , or a combination of both grasper and suture, to facilitate placement of flexible injection port  30  in the body.  
         [0024]     Although flexible injection port  30  is shown in  FIG. 3  to be essentially straight, it is possible to construct it with a curved or non-straight shape in order to facilitate placement in the body, or to conform to the body anatomy at the implant location. Since flexible injection port  30  is made of relatively soft and flexible materials, the surgeon may temporarily straighten it, for example, when introducing it into the body through a laparoscopic port.  
         [0025]      FIG. 4  is a cross sectional view of flexible injection port  30 , taken at line  44  of injection portion  32  as shown in  FIG. 3 . At this location and anywhere along the length of injection portion  32 , flexible injection port  30  includes an outer tube  44  may exerts a radial, compressive force on an inner tube  46 . Flexible injection port  30  includes a fluid reservoir  48  that extends the entire length of injection portion  32  and fluidly communicates with catheter  42 . The total wall thickness is approximately in the range of 2-4 mm.  
         [0026]      FIG. 5  is a longitudinal sectional view of flexible injection port  30 , showing a hypodermic needle  100  penetrating through injection portion  32  so that distal tip  102  of hypodermic needle  100  is inside of fluid reservoir  48 . First end  34 , second end  36 , tether  38 , eye loop  40 , and inner tube  46  are integrally molded from an elastomer such as, for example, silicone rubber, latex rubber, or polyurethane rubber. The molded elastomer may have a durometer approximately in the range of 40-60, but is not limited to that range. Catheter  42  may be bonded inside of first end  34  using any one of a number of bonding agents and techniques well known in the art, in order to fluidly communicate with reservoir  48 . Outer tube  44  may be made of a PTFE shrink-wrap material, or a similar, biocompatible shrink-wrap. During the manufacturing process, outer tube  44  may be loosely assembled in the pre-shrunken configuration over inner tube  46 . Then the application of heat causes outer tube  44  to conform very tightly around inner tube  46 . Outer tube  44  therefore applies a significant compressive force on the softer, inner tube  46  to enhance the ability of inner tube  46  to close the puncture created by hypodermic needle  100 .  
         [0027]      FIG. 6  is a cross sectional view of a second embodiment of the present invention showing a flexible injection port  50 , which is externally similar to the first embodiment shown in  FIG. 3 . Flexible injection port  50  includes an outer tube  52 , an inner tube  54 , and an inner lining  56 . Outer tube  52  and inner tube  54  are the same as outer tube  44  and inner tube  46 , respectively, of the first embodiment in  FIG. 4 . Inner lining  56  may be an extruded plastic, thin wall tube, such as polyethylene or PTFE, tightly assembled inside of inner tube  54  to provide internal support to inner tube  54 . By supporting inner tube  54  in this way, a greater compressive force may be applied by outer tube  52  onto inner tube  54 , to further enhance the self-sealing capability. The material of inner lining  56  may be selected to have a higher needle penetration resistance than inner tube  54 . This difference in penetration resistance provides the surgeon with tactile feedback that the needle tip has penetrated into fluid reservoir  58 . Inner lining  56  may also be constructed of a metallic mesh and be similar in many respects to a vascular stent. Again, the total wall thickness is approximately in the range of 2-4 mm.  
         [0028]      FIG. 7  is a cross sectional view of a third embodiment of the present invention showing a flexible injection port  60 , which also is externally similar to the first embodiment shown in  FIG. 3 . Flexible injection port  60  comprises a plurality of layers  61 , which for this third embodiment includes a first layer  62 , a second layer  64 , a third layer  66 , a fourth layer  68 , and a fifth layer  70 , which surrounds a fluid reservoir  72 . Once penetrated by a needle that is inserted at an acute angle, the punctures created through the layers are not aligned to allow leakage once the needle is removed. Each of layers  61  may be made of the same or a different material than any of the other of layers  61 , or may have the same or a different thickness than any of the other of layers  61 . Each of layers  61  may have a specific property or functional contribution. For example, first layer  62  may be made of a material that is, permeable to tissue fluids in order to slowly release a medication contained in second layer  64 . Fifth layer  70  may be made of silicone rubber having a durometer in the range of 20-30. Fourth layer  68  may be made of a heat shrinkable PTFE material, which applies a radially compressive force on fifth layer  70  to enhance self-sealing. Third layer  66  may be made of a material such as a metallic foil that acts as a diffusion barrier to prevent the loss of fluid from fluid reservoir  72 . Fourth layer  66  may be made of a high durometer silicone rubber. Many other materials are possible, in a multiplicity of combinations, so that injection port  60  may have characteristics especially suited for its particular application. Diffusion of body fluids into and out of the soft port wall may also be reduced by any one of various material treatment techniques, including, for example, vapor deposition of titanium or another metal on a surface of the soft port, and coating with Paralene polymer. Other coatings are also known in the art for micro bacterial protection. Again, the total wall thickness is in the range of 2-4 mm.  
         [0029]      FIG. 8  is a fourth embodiment of the present invention, a flexible injection port  80 , comprising a first end  84  that attaches to a catheter  92 , a second end  86  and an injection portion  82 . Flexible injection port  80  further comprises a webbing  88  attached to and covering at least injection portion  82 , and made of a thin, flexible, implantable material such as a polyester or polypropylene mesh, expanded PTFE, or the like. Webbing  88  provides broad margins for stapling or suturing to an underlying tissue such as fascia, as well as a large area for tissue in-growth, to enhance long-term stability and to substantially prevent migration of flexible injection port  80 .  FIG. 9  is a cross sectional view of flexible injection port  80 , taken at line  9 - 9  of  FIG. 8 . Flexible injection port  80  comprises an outer tube  94  made of a heat shrinkable, PTFE material, and an inner tube  96  made of a silicone rubber having a durometer of approximately 20-40. Webbing  88  includes a pair of webbing layers,  91  and  93 , that may be bonded thermally or chemically tightly over at least injection portion  82  in the mid-plane of flexible injection port  80 .  
         [0030]     A surgeon may implant the present invention, as described for the preceding embodiments and equivalents, in a number of locations in a patient&#39;s body.  FIGS. 10, 11 , and  12  show examples of flexible injection port  30  subcutaneously implanted in the abdomen of a patient, although it is possible to implant flexible injection port  30  beneath the skin in other portions of the body.  
         [0031]      FIG. 10  depicts a first example of flexible injection port  30  subcutaneously implanted in a patient&#39;s body. Flexible injection port  30  lies adjacent to a fascia layer  124  covering an abdominal wall  126 . Catheter  42  passes from the abdominal cavity  128  through an abdominal opening  132 , which the surgeon used together with a first incision  130  for laparoscopic access earlier in the surgical procedure. The surgeon optionally may make a second incision  134  offset from first incision  130 , and use conventional, surgical grasping and retracting instruments to pull flexible injection port  30  beneath a fat layer  122  and adjacent to fascia layer  124 . However, the surgeon may determine that it is not necessary to make a second incision  134 , and instead use first incision  130  to push flexible injection port  30  into position. In either situation, the surgeon dissects as little tissue as practical in order to save surgery time and to minimize the size of enclosed cavities that may collect tissue fluids and become sites for infection. The surgeon optionally may anchor flexible injection port  30  to fascia layer  124  with a stay suture  102 . Once the surgeon has placed flexible injection port  30  in the desired location, the surgeon closes first incision  130  and second incision  134  using conventional sutures or staples.  
         [0032]      FIG. 11  shows a second example of flexible injection port  30  subcutaneously implanted in a patient&#39;s body. Flexible injection port  30  lies immediately beneath skin layer  120  and above fat layer  122 . Catheter  42  passes through first incision  130  and abdominal opening  132  (the original laparoscopic port site) into abdominal cavity  128 . The surgeon may use finger or instrument dissection through first incision  130  to create a space under skin layer  120  for flexible injection port  30 . The surgeon closes first incision  130  using conventional sutures or staples. Normally it would not be necessary to close abdominal opening  132  through fascia layer  124  and abdominal wall  126 , but the surgeon may do so in order to promote healing and to prevent slippage of catheter  42  through abdominal opening  132 . The surgeon may prefer placement of flexible injection port  30  just beneath skin layer  120  for severely obese patients in which fat layer  122  is over 5-10 cm thick, so that the surgeon may easily use palpation to locate flexible injection port  30  for later injections of fluid. Also, conventional intravenous (IV) needles and techniques may be used for injecting the fluid into flexible injection port  30 , which is situated beneath the skin much like a natural blood vessel. This may allow nurses and other clinicians who are trained in administering IV&#39;s to assist the surgeon with fluid injections. Furthermore, if the clinician uses a conventional IV needle, the “flashback” of fluid into the IV needle syringe tip provides the clinician with visual feedback that the tip of the needle is properly penetrated into the reservoir of flexible injection port  30 . In fact, addition of a colorant to the fluid injected further enhances this visual feedback. Non-toxic colorants that may be added to the saline solution or medication are well known in the art.  
         [0033]      FIG. 12  shows a third example of flexible injection port  30  subcutaneously implanted in a patient&#39;s body. For this example, the surgeon does minimal or no dissection of tissue at the laparoscopic port site. Catheter  42  passes from the abdominal cavity  128  through fascia layer  124  and abdominal wall  126 . The surgeon positions flexible injection port  30  vertically in fat layer  122  and beneath skin layer  120 . Optionally, the surgeon may suture abdominal opening  132  to prevent slippage of flexible injection port  30  into abdominal cavity  128 . The surgeon also may use a surgical scissors to trim off tether  38  from flexible injection port  30 , just prior to closing first incision  130  with conventional sutures or staples.  
         [0034]     The present invention, a flexible injection port, as described in the preceding embodiments and their equivalents, has numerous advantages over the prior art injection ports. The flexible injection port may not require attachment to fascia, thus reducing the duration of the surgical procedure. The flexible injection port may require a smaller incision size and less tissue dissection for implantation, so that the patient has less pain, less scarring, a faster recovery, and less possibility of infection. Due to the integral construction of the flexible injection port and the catheter, the step of connecting the catheter to the injection port during the surgical procedure is not necessary, thus potentially reducing the number of surgical complications due to fluid leakage at the connection. Because the flexible injection port may be implanted in the fat layer near the skin surface, the surgeon or a trained clinician may use palpation to locate the injection port, and standard IV techniques to administer fluid, yet the implant is still cosmetically acceptable to the patient. In addition, shorter injection needles may be used to reduce patient anxiety during fluid administration. The flexible injection port may have no metallic parts, resulting in a flexible and lightweight implant for greater patient comfort and compatibility with magnetic resonance and fluoroscopic x-ray imaging. Finally, the injection portion of the flexible injection port is accessible with a hypodermic needle for most of the possible orientations of the flexible injection port within the subcutaneous fat layer of the patient.  
         [0035]     While preferred embodiments of the present invention have been shown and described herein, it will be obvious to those skilled in the art that such embodiments are provided by way of example only. Numerous variations, changes, and substitutions will now occur to those skilled in the art without departing from the invention. For example, the injection port may me coated with an anit-microbial coating such as triclosan. For example, as would be apparent to those skilled in the art, the disclosures herein have equal application in robotic-assisted surgery. In addition, it should be understood that every structure described above has a function and such structure can be referred to as a means for performing that function. Accordingly, it is intended that the invention be limited only by the spirit and scope of the appended claims.