Abstract:
A method of repositioning an injection port comprises positioning the injection port at a first location in a patient&#39;s body and extending fasteners of the injection port to substantially secure the injection port at the first location. The fasteners are then retracted to substantially unsecure the injection port from the first location in the patient&#39;s body. The injection port is then moved to a second location in the patient&#39;s body. The fasteners are then re-extended to substantially secure the injection port at the second location in the patient&#39;s body. The injection port includes a port body. The fasteners are integral with the port body. The fasteners may be selectively extended and retracted relative to the port body. For instance, the fasteners may be pivoted relative to the port body to transition between extended and retracted positions. The extension and retraction of fasteners may be provided through a port applier.

Description:
[0001]    This application is a continuation of U.S. patent application Ser. No. 11/166,625, filed Jun. 24, 2005, entitled “Implantable Medical Device with Reversible Attachment Mechanism and Method,” published as U.S. Pub. No. 2005/0283119, which is a continuation-in-part of U.S. patent application Ser. No. 10/741,875, filed Dec. 19, 2003, entitled “Subcutaneous Self Attaching Injection Port with Integral Moveable Retention Members,” published as U.S. Pub. No. 2004/0254537, which claims priority to U.S. Provisional Patent Application Ser. No. 60/478,763, filed Jun. 16, 2003, entitled “Fluid Injection Port for Adjustable Gastric Band.” The disclosure of each of those three patent applications is incorporated by reference herein. 
         [0002]    This application also incorporates by reference the following United States patent applications, both of which were filed on Dec. 19, 2003: application Ser. No. 10/741,127, entitled “Subcutaneous Injection Port for Applied Fasteners,” published as U.S. Pub. No. 2005/0131352; and application Ser. No. 10/741,868, entitled “Subcutaneous Self Attaching Injection Port with Integral Fasteners,” issued as U.S. Pat. No. 7,374,557. 
     
    
     TECHNICAL FIELD 
       [0003]    The present invention relates generally to medical implants and appliers therefor, and more particularly to an attachment mechanism for use with a variety of medical implants and appliers for attaching such medical implants to body tissue. The invention will be disclosed in connection with, but not limited to, surgically implantable injection ports and an applier therefor. 
       BACKGROUND 
       [0004]    Implantable medical devices are typically implanted in a patient to perform a therapeutic function for that patient. Non-limiting examples of such devices include pace makers, vascular access ports, injection ports (such as used with gastric bands) and gastric pacing devices. Such implants need to be attached, typically subcutaneously, in an appropriate place in order to function properly. It is desirable that the procedure to implant such devices be quick, easy and efficient. In many instances it would be beneficial if the surgeon could remove or reposition the device quickly, easily and efficiently. 
         [0005]    Injection ports are placed beneath the skin of a body for injecting fluids into the body, such as for infusing medication, blood draws, and many other applications, including adjustable gastric bands. Since the early 1980s, adjustable gastric bands have provided an effective alternative to gastric bypass and other irreversible surgical weight loss treatments for the morbidly obese. The gastric band is wrapped around an upper portion of the patient&#39;s stomach, forming a stoma that restricts food passing from an upper portion to a lower portion of the stomach. When the stoma is of the appropriate size, food held in the upper portion of the stomach provides a feeling of fullness that discourages overeating. However, initial maladjustment or a change in the stomach over time may lead to a stoma of an inappropriate size, warranting an adjustment of the gastric band. Otherwise, the patient may suffer vomiting attacks and discomfort when the stoma is too small to reasonably pass food. At the other extreme, the stoma may be too large and thus fail to slow food moving from the upper portion of the stomach, defeating the purpose altogether for the gastric band. 
         [0006]    In addition to a latched position to set the outer diameter of the gastric band, adjustability of gastric bands is generally achieved with an inwardly directed inflatable balloon, similar to a blood pressure cuff, into which fluid, such as saline, is injected through a fluid injection port to achieve a desired diameter. Since adjustable gastric bands may remain in the patient for long periods of time, the fluid injection port is typically installed subcutaneously to avoid infection, for instance in front of the sternum. Adjusting the amount of fluid in the adjustable gastric band is achieved by inserting a Huber needle through the skin into a silicon septum of the injection port. Once the needle is removed, the septum seals against the hole by virtue of compressive load generated by the septum. A flexible conduit communicates between the injection port and the adjustable gastric band. 
         [0007]    The present invention encompasses an attachment mechanism to secure an medical implant device to body tissue quickly and easily. The attachment mechanism may be reversible, allowing the implantable medical device to be detached quickly and easily for repositioning or removal. Although standard, commercially available instruments may be used to actuate the attachment mechanism, the present invention also encompasses an applier for locating an implantable medical device in the desired location and quickly and easily actuating the attachment mechanism to secure the implantable medical device. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]    The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention, and, together with the general description of the invention given above, and the detailed description of the embodiments given below, serve to explain the principles of the present invention. 
           [0009]      FIG. 1  is a perspective view of an injection port with an attachment mechanism constructed in accordance with the present invention. 
           [0010]      FIG. 2  is a top view of the injection port of  FIG. 1 . 
           [0011]      FIG. 3  is a bottom view of the injection port of  FIG. 1 . 
           [0012]      FIG. 4  is a cross sectional view of the injection port of  FIG. 1  taken along line  4 - 4  of  FIG. 3 . 
           [0013]      FIG. 5  is an exploded perspective view of the injection port of  FIG. 1 . 
           [0014]      FIG. 6  is perspective view of the bottom of the injection port of  FIG. 1 , showing the attachment mechanism in the retracted position. 
           [0015]      FIG. 7  is a perspective view of the bottom of the injection port of  FIG. 1 , similar to  FIG. 6 , showing the attachment mechanism in the extended/fired position. 
           [0016]      FIG. 8  is a side cutaway view in partial cross-section illustrating a fastener of the attachment mechanism in the retracted position. 
           [0017]      FIG. 9  is a side cutaway view in partial cross-section similar to  FIG. 8  illustrating a fastener of the attachment mechanism that is being advanced by the actuator ring toward the extended/fired position. 
           [0018]      FIG. 10  is a side cutaway view in partial cross-section similar to  FIG. 8  illustrating a fastener of the attachment mechanism in the extended/fired position. 
           [0019]      FIG. 11  is a side cutaway view in partial cross-section similar to  FIG. 8  illustrating a fastener of the attachment mechanism that is being advanced by the actuator ring toward the retracted position. 
           [0020]      FIG. 12  is a top view of the injection port of  FIG. 1 , with the actuator ring omitted to illustrate the positions of the links when the fasteners are in the retracted position. 
           [0021]      FIG. 13  is a top view of the injection port of  FIG. 1 , with the actuator ring omitted to illustrate the positions of the links when the fasteners are in the extended/fired position. 
           [0022]      FIG. 14  is an enlarged, fragmentary top view of the visual position indicator and actuator ring detent system of the attachment mechanism of  FIG. 1 , in the retracted position. 
           [0023]      FIG. 15  is an enlarged, fragmentary top view of the visual position indicator and actuator ring detent system of the attachment mechanism of  FIG. 1  in the extended/fired position. 
           [0024]      FIG. 16  is an enlarged, fragmentary, exploded perspective view of the fitting and locking connector of the injection port of  FIG. 1 . 
           [0025]      FIG. 17  is an enlarged, fragmentary partial cross-section view of the locking connector assembled to the fitting the septum retainer but not locked in place. 
           [0026]      FIG. 18  is an enlarged, fragmentary partial cross-section view similar to  FIG. 17  showing the locking connector locked in place. 
           [0027]      FIG. 19  is an enlarged perspective view of the safety cap. 
           [0028]      FIG. 20  is a perspective view of an applier constructed to implant the injection port of  FIG. 1 . 
           [0029]      FIG. 21  is a exploded, perspective view of the applier of  FIG. 20 . 
           [0030]      FIG. 22  is a side view of the applier of  FIG. 20  with one of the two body halves showing the internal components in the unapplied, non-actuated position. 
           [0031]      FIG. 23  is a side view of the applier of  FIG. 20  similar to  FIG. 22 , showing the internal components in the applied, actuated position. 
           [0032]      FIG. 24  is an enlarged, fragmentary side view of the linear to rotary cam mechanism of the applier of  FIG. 20 . 
           [0033]      FIG. 25  is an enlarged top perspective view of the locator of the applier of  FIG. 20 . 
           [0034]      FIG. 26  is an enlarged bottom perspective view of the locator and the port actuator of the applier of  FIG. 20 . 
           [0035]      FIG. 27  is a partially cut away end view of the locator of the applier of  FIG. 20 . 
           [0036]      FIG. 28  is an enlarged, cross sectional view of the injection port of  FIG. 1  retained by the locator of the applier of  FIG. 20 . 
           [0037]      FIG. 29  is an enlarged, cross-sectional view of the injection port of  FIG. 1  disposed in the locator of the applier of  FIG. 20  after the applier has been actuated to rotate the applier actuator to the deployed position. 
           [0038]      FIG. 30  is a diagrammatic drawing showing an injection port connected to an adjustable gastric band wrapped around an upper part of a stomach. 
       
    
    
       [0039]    Reference will now be made in detail to the present preferred embodiment of the invention, an example of which is illustrated in the accompanying drawings. 
       DETAILED DESCRIPTION 
       [0040]    In the following description, like reference characters designate like or corresponding parts throughout the several views. Also, in the following description, it is to be understood that terms such as front, back, inside, outside, and the like are words of convenience and are not to be construed as limiting terms. Terminology used in this patent is not meant to be limiting insofar as devices described herein, or portions thereof, may be attached or utilized in other orientations. Referring in more detail to the drawings, an embodiment of the invention will now be described. 
         [0041]    Referring to  FIGS. 1-5 , there is shown an implantable medical device, more specifically an injection port, generally indicated at  2 , which embodies an attachment mechanism constructed in accordance with the present invention. Although the attachment mechanism is illustrated in the figures as being embodied with injection port  2 , the attachment mechanism may be used with any implantable medical device for which it is suited, including by way of example only pace makers, vascular access ports, injection ports (such as used with gastric bands) and gastric pacing devices. 
         [0042]    Injection port  2  includes septum retainer  4 , septum  6  and port body  8 . Injection port  2 , with the integrally constructed attachment mechanism, also includes one or more fasteners  10 , actuator  12  and a plurality of link members  14 . 
         [0043]    As seen in  FIG. 4 , septum  6 , which may be made of any biocompatible material such as silicone, is disposed partially within internal cavity  16  of septum retainer  4 , adjacent annular flat  18 . Septum retainer  4 , port body  8 , and actuator  12  may be made of any suitable biocompatible material having sufficient stiffness and strength, such as polyetheretherketon (known as PEEK). Fasteners  10  and link members  14  may be made of any suitable biocompatible material, such as stainless steel. 
         [0044]    Port body  8  includes annular rim  20 , which engages the upper surface of septum  6  about an annular portion. Port body  8  is retained to septum retainer  4  by a plurality of pins  22  which are disposed through respective holes  24  formed in recesses  24   a  in port body  8  and which extend inwardly into respective recesses  26  formed about the bottom periphery of septum retainer  4 . Pins  22  may be made of any suitable biocompatible material, such as stainless steel. 
         [0045]    The uncompressed height of septum  6  is approximately 5 mm around the outer diameter and the uncompressed diameter is approximately 18 mm. The exposed diameter for access to reservoir  20  is approximately 14 mm The distance between the lower surface of annular rim  20  and annular flat  18  is approximately 4 mm, such that septum  6  is compressed approximately 20% to be adequately self healing to maintain a fluid tight system under pressure and still allow a low profile. 
         [0046]    Plate  28  is disposed in recess  16   a  formed in the bottom of septum retainer  4 , underlying septum  6  and fluid chamber or reservoir  30 . As seen in  FIG. 4 , plate  28  does not contact sidewall  16   b . In the embodiment depicted, plate  28  is metallic, such as stainless steel. When a needle is inserted through septum  6  to introduce or withdraw fluid from fluid chamber  30 , such as in order to adjust the size of an adjustable gastric band, metallic plate  28  will protect septum retainer  4  from puncture and provide tactile feedback to the surgeon through the needle indicating that the needle has bottomed in reservoir  30 . Plate  28  may be secured to septum retainer  4  in any suitable manner. In the embodiment depicted, plate  28  is held in place by retaining lip  4   a  extending over the periphery of plate  28  as best seen in  FIGS. 4 ,  28  and  29 . Initially, retaining lip  4   a  extends upwardly as an annular lip, providing clearance for insertion of plate  28  into the recess at the bottom of septum retainer  4 , and retaining lip  4   a  is then rolled or otherwise deformed to overlie at least a portion of the periphery of plate  28  thereby retaining plate  28 . In the embodiment depicted the diameter of recess  16   a  is smaller than the diameter of sidewall  16   b , providing room to form the annular lip and to deform it into retaining lip  4   a . Plate  28  could be insert molded, with retaining lip  4   a  molded as illustrated. 
         [0047]    Septum retainer  4  includes passageway  32 , in fluid communication with fluid chamber  30 , which is defined by fitting  34  extending from the periphery adjacent the bottom of retainer  4 . Tube  36 , which in the embodiment depicted, leads to an adjustable gastric band (not shown), is connected to fitting  34 , being compressingly urged against annular rib  38  by connector  40 , which is disposed about tube  36  and secured to port body  8  as described below. Sleeve  42  is disposed about tube  36 , secured to connector  40  by annular ribs  44 . Sleeve  42  relieves strain on tube  36 , preventing tube  36  from kinking when loaded laterally. 
         [0048]    Actuator  12  is secured to port body  8 . Although in the embodiment depicted actuator  12  is illustrated as an annular ring rotatably supported by port body  8 , actuator  12  may be any suitable configuration and supported in any suitable manner to permit actuator  12  to function to move fasteners  10  between and including deployed and undeployed positions. As seen in  FIG. 5 , port body  8  includes a plurality of downwardly and outwardly extending tabs  46 . In the embodiment depicted, there are four equally spaced tabs  46 . Actuator  12  includes an equal number of corresponding recesses  48 , each having arcuate bottom  50 . To assemble actuator  12  to port body  8 , recesses  48  are aligned with tabs  46 , and pushed down, temporarily deflecting tabs  46  inwardly until tabs  46  reach recesses  48  and move outwardly to dispose lower edges  46   a  in recesses  48  such that actuator is retained thereby. The lengths of tabs  46  and depth of recesses  48  allow some axial end play between actuator  12  and port body  8 , as will be described below. 
         [0049]    Actuator  12  may rotate generally about the central axis of port body  8 . In the embodiment depicted, actuator  12  may rotate through an angle of about 40 degrees, although any suitable angle may be used. In the embodiment depicted, when actuator  12  is rotated in the deploying direction, causing fasteners  10  to move to the deployed position, rotation of actuator  12  beyond the fully deployed position is limited by end  48   c  contacting tab  46 . 
         [0050]    A detent system is formed by a pair of spaced apart raised detent ribs  48   a ,  48   b  extending inwardly from the wall of each recess  48 , and a corresponding raised rib  46   b  extending outwardly from tab  46 . The detent system assists in preventing actuator  12  from rotation and fasteners  10  from moving out of fully retracted or fully extended fired states under vibration or incidental loads, as described below. 
         [0051]    Actuator  12  includes a plurality of spaced apart openings or slots  54 , which may be engaged by any suitable instrument to transmit the necessary torque to actuator  12  to extend fasteners  10  to the actuated position. Slots  54  are configured to be engaged by commercially available instruments, rectangular in the embodiment depicted, or by the dedicated applier described below. Port body  8  includes a plurality of recesses  56  disposed about its lower periphery which are configured to cooperate with the dedicated applier as described below. 
         [0052]    Referring also to  FIGS. 6 and 7 , septum retainer  4  includes a plurality of locating tabs  58  extending outwardly from adjacent the bottom periphery of septum retainer  4 . Locating tab  58   a  may be integral with fitting  34 . Tabs  58  and  58   a  are located in respective complementarily shaped recesses  60  formed in the inner surface of port body  8 , aligning septum retainer  4  properly with port body  8 . 
         [0053]      FIG. 6  illustrates fasteners  10  in the retracted position. As can be seen, fasteners  10  are disposed in respective recesses or slots  60  formed in port body  8 .  FIG. 7  illustrates fasteners  10  in the extended, or fired, position, extending from slots  60 . Rotation of actuator  12  moves fasteners  10  from the retracted position to the extended position. 
         [0054]      FIGS. 8-11  are a series of figures illustrating the operation of actuator  12  and one of the plurality of fasteners  10 , it being understood that the operation on one of fasteners  10  may be the same as for all fasteners  10 , which may, in one embodiment, be moved from a deployed position to an undeployed position simultaneously.  FIG. 8  illustrates fastener  10  in a fully retracted state, the undeployed position, disposed completely within slot  62  such that sharp tip  64  is not exposed. This prevents tip  64  from accidentally sticking the surgeon or penetrating any object. Actuator  12  is illustrated rotated counter clockwise as far as permitted by recesses  48  and tabs  46 . In this position, ribs  46   b  are disposed clockwise of ribs  48   b , as seen in  FIG. 14 . First ends  14   a  of link members  14  are rotatably carried by actuator  12 , spaced apart at positions corresponding to the positions of fasteners  10 . Second ends  14   b  are disposed within openings  66  of fasteners  10 . 
         [0055]    To actuate the attachment mechanism, integral actuator  12  is rotated in a deploying direction, which in one embodiment as depicted is clockwise (any suitable direction configured to actuate the attachment mechanism may be used), and rib  46   b  passes rib  48   b , which may produce an audible signal in addition to a tactile signal to the surgeon. Second end  14   b  of link member  14  is free to move within slot  66  during actuation, as the force that rotates fastener  10  into the extended position is transmitted to fastener  10  through the interaction between cam surface  68  of fastener  10  and actuating cam surface  70  of actuator  12 . As actuator  12  rotates clockwise, actuating cam surface  70  engages and pushes against cam surface  68 , rotating fastener  10  about pivot pin  22 . The majority of the force from actuating cam surface  70  acts tangentially on cam surface  68 , off center relative to pivot pin  22 , causing fastener  10  to rotate. During actuation, end  14   b  of link member  14  remains free to move within slot  66 , applying no driving force to rotate fastener  10 . 
         [0056]    In  FIG. 9 , fastener  10  is rotated about half way though its range of rotation, about 90 degrees as a result of the clockwise rotation of actuator  12 . As actuator  12  is rotated clockwise, the force between actuator cam surface  70  and cam surface  68  causes actuator  12  to move upward slightly as allowed by the tolerancing of the components. As actuator  12  is rotated further clockwise from the position shown in  FIG. 9 , actuator cam surface  70  continues to engage and push against cam surface  68 , rotating fastener  10  further counterclockwise. 
         [0057]    In  FIG. 10 , actuator  12  is rotated clockwise to its fullest extent, with rib  46   b  having been urged past detent rib  48   a  (see  FIG. 15 ). In this position, fastener  10  has rotated to its fullest extent, almost 180 degrees in the embodiment illustrated, with tip  64  disposed within recess  62 . In this position, actuator cam surface  70  is over center, and actuator  12  is resistant to being back driven by an undeploying force imparted to fastener  10  as cam surface  68  acts against actuator cam surface  70  in a direction that tends to push actuator  12  up instead of rotating actuator  12 . The distal end portion of fastener  10  is configured essentially as a beam, depicted as having a generally rectangular cross section along its length, tapering to sharp tip  64 . With fastener  10  extending approximately 180 degrees in the fully extended state, the deployed position, forces which might act on fasteners  10  tend to act through the pivot axis defined by pivot pin  22 , instead of rotating fasteners  10 . It is noted that although pin  22  is illustrated as being a separate piece from fastener  10 , the two may be integral or even of unitary construction. 
         [0058]    If it is desirable to retract fasteners  10 , such as to remove or reposition the implanted device, actuator  12  may be rotated in an undeploying direction, counterclockwise in one embodiment depicted. Starting with the position of actuator  12  shown in  FIG. 10 , actuator  12  may be rotated counterclockwise, with actuator cam surface  70  sliding against cam surface  68 , without rotating fastener  10 . In the embodiment depicted, continued counterclockwise rotation of actuator  12  moves cam surface  70  out of contact with cam surface  68 , with no substantial rotating force being exerted on fastener  10  until second end  14   b  of link member reaches a location in slot  66 , such as at one end of slot  66 , at which link member  14  begins pulling against slot  66  causing fastener  10  to rotate and begin to retract. 
         [0059]    As seen in  FIG. 11 , actuator  12  has been advanced counterclockwise compared to the position shown in  FIG. 10 , and fastener  10  is rotated approximately halfway through its range. As can be seen by comparing  FIG. 9  to  FIG. 11 , actuator  12  is in different positions with fastener  10  in the same position, in dependence upon whether the attachment mechanism is being actuated or deactuated (retracted). This results from the lost motion that results when link member  14  is pulling on slot  66  in comparison to actuator cam surface  70  pushing directly on cam surface  68 . To retract fasteners  10  fully, actuator  12  is rotated until detent rib  46   b  snaps past detent rib  48   b.    
         [0060]    Referring to  FIG. 8 , when fasteners  10  reach the fully undeployed position tip  64  may be disposed fully in slot or recess  62 . Further undeploying rotation of actuator  12  is prevented by link member  14  which is prevented from further movement by fastener  10 . 
         [0061]    Referring to  FIGS. 2 and 3 , actuator  12  includes openings  52   a  formed therethrough, which align with corresponding openings  52   b  formed in port body  8  when actuator is in the undeployed position. Openings  52   a  and  52   b  may be used by the surgeon to suture injection port  2  if the integral attachment mechanism is not used. 
         [0062]    Referring to  FIGS. 12 and 13 , the attachment mechanism is shown without actuator  12 . Link members  14  are shown in their actual positions when first ends  14   a  are supported by actuator  12 , in the deployed and in the undeployed states. 
         [0063]    Referring to  FIGS. 14 and 15 , there is illustrated a top view of the visual position indicator and a portion of the actuator ring detent system of the attachment mechanism as embodied in injection port  2 . In  FIG. 14 , the attachment mechanism is in the retracted, undeployed state or position. In this position, detent rib  46   b  is clockwise of detent rib  48   b , and thus in the undeployed detent position. In  FIG. 15 , the attachment mechanism is in the actuated or deployed position. In this position, detent rib  46   b  is counterclockwise of detent rib  48   b , and thus in the deployed detent position. 
         [0064]      FIGS. 14 and 15  illustrate a visual indicator of the state of the attachment mechanism. As seen in  FIG. 14 , indicia may be utilized, such as an unlocked lock icon  72  and a locked lock icon  74  molded integral with actuator ring  12 . Any suitable graphic indicator may be used, and may be printed on or otherwise applied in a suitable manner. Port body  8  may include indicator  76  to provide a reference point for the movable indicia. Arrow  78  may be included to indicate the bidirectional motion of actuator  12 . 
         [0065]      FIGS. 16-18  illustrate the locking connection between connector  40  and port body  8 .  FIG. 16  is an exploded perspective view showing fitting  34  partially surrounded by extension  78 .  FIG. 17  shows extension  78  in cross-section, with connector  40  generally disposed about fitting  34  and tube  36  aligned in circumferential slot  78   c  of extension  78 . Connector  40  includes a pair of tabs  40   a ,  40   b , extending outwardly therefrom. To assemble, connector  40  is guided along tube  36  and fitting  34 , with tabs  40   a  and  40   b  aligned with openings  78   a  and  78   b  of extension  78 . With tabs  40   a  and  40   b  aligned with circumferential slot  78   c , connector  40  is rotated to lock it in place. During rotation, detent edge  78   d  creates interference opposing the rotation of tab  40   a , but is dimensioned to allow tab  40   a  to be rotated past, to the locked position seen in  FIG. 18 . 
         [0066]      FIG. 19  illustrates safety cap  80  which may be removably secured to the bottom of injection port  2  to cover fasteners  10  to protect users from accidental exposure to sharp tips  64  while handling injection port  2 . Safety cap  80  includes body  82  with annular rim  84  and raised center  86  defining annular recess  88 . Safety cap  80  may be oriented and retained to injection port through any suitable configuration. As depicted, body  82  includes a plurality of arcuate retention tabs  90  extending upwardly from raised center  86 . Arcuate retention tabs  90  are shaped complementarily to corresponding arcuate slots  92 , best seen in  FIGS. 3 ,  6  and  7 , and may have ribs as shown. Safety cap  80  is secured to injection port  2  by inserting arcuate retention tabs  90  into arcuate slots  92 , which are sized to retain tabs  90 . Fasteners  10  are thus aligned with annular recess  88 , which is sized to allow fasteners  10  to be extended without contacting safety cap  80 . As depicted, since arcuate retention tabs  90  and arcuate slots  92  are respectively the same size and equally spaced, safety cap  80  is not indexed to a particular position, and may be secured to injection port  2  in four different positions. Safety cap  80  includes pull tab  94  with raised a plurality of ribs  96  to provide a better gripping surface. Although pull tab  94  may be oriented in any suitable orientation, in the embodiment, the relative position between pull tab  94  and arcuate retention tabs  90  locates pull tab at 45 degrees to the direction of connector  40 . Tabs  90  and slots  92  may be of any suitable shape. 
         [0067]    As mentioned previously, the attachment mechanism may be actuated by engaging slots  54  with commercially available instruments or by a dedicated applier.  FIG. 20  illustrates applier, generally indicated at  100 , which is configured to position, actuate, deactuate, remove or reposition injection port  2 . It is noted that the practice of aspects of the present invention as applied to an applier is not limited to the specific applier embodiment depicted herein. 
         [0068]    As shown in  FIG. 20 , applier  100  includes body  102 , locator  104 , actuator  106  and safety switch  108 . As will be described below, injection port  2  may be assembled to locator  104 , with extension  78  and tab  96  disposed in alignment slots  110  and  112 . Locator  104  is angled relative to body  102 , allowing for easier and better visualization of injection port  2  during implantation. In the embodiment depicted, the angle is 20 degrees and the shaft portion of body  102  is 10 cm. 
         [0069]    Referring to  FIG. 21 , body  102  includes first and second halves  102   a  and  102   b  assembled to each other to contain the internal components. Except for locating pins  202 , pivot pins  114  and ship laps, body halves  102   a  and  102   b  are substantially similar to each other. Locating pins  202 , illustrated as extending from body half  102   a , fit into respective complementarily shaped openings (not illustrated) on body half  102   b . The engagement of the plurality of locating pins  202  in the openings is sufficient to hold body halves  102   a  and  102   b  together. Pins  202  may alternatively extend from body half  102   b  with the openings carried by body half  102   a . Any suitable configuration may be used to assemble and secure body halves  102   a  and  102   b  together. 
         [0070]    Actuator  106  includes first and second halves  106   a  and  106   b . Locating pins  204 , illustrated as extending from actuator half  106   a , fit into respective complementarily shaped openings (not illustrated) on actuator half  106   b . Pins  204  may alternatively extend from actuator half  106   b  with the openings carried by actuator half  106   a . Any suitable configuration may be used to assemble and secure actuator halves  106   a  and  106   b  together. Body half  102   b  includes pivot pin  114   b  which rotatably supports actuator  106  at one end, extending through pivot holes  116   a  and  116   b  into opening  114   a . Body half  102   a  includes pivot pin  118   b  (see  FIG. 22 ) which rotatably supports safety switch  108 . Body halves  102   a  and  102   b , locator  104 , actuator halves  106   a  and  106   b , and safety switch  108  may be made of any biocompatible material such as polycarbonate. 
         [0071]    Referring to  FIGS. 21-24 , applier  100  includes cam  120 , drive shaft  122  with flexible shaft  124 , drive shaft pin  126 , cam return spring  128 , safety biasing spring  130 , and actuator  132 . Actuator  132  is configured to effect the deployment or undeployment of the attachment mechanism of the medical implant. Cam  120  includes shaft  134  and cam collar  136 . The upper end of shaft  134  has a “T” configuration terminating in cross member  138 . Cam collar  136  defines a hollow interior and a pair of spaced apart, complementarily shaped cam tracks  140   a  and  140   b  formed on opposite sides of cam collar  136 . Upper end  122   a  of drive shaft  122  is disposed partially within the hollow interior defined by cam collar  136 , captured therein by drive shaft pin  126 . Drive shaft pin  126  is sized such that each end is located within a respective cam track  140   a ,  140   b . The length of the hollow interior allows upper end  122   a  to reciprocate therein, with cam tracks  140   a  and  140   b  imparting rotation to drive shaft  122  through drive shaft pin  126  during reciprocation. Cam  120 , drive shaft  122  and actuator  132  may be made of any suitable material having sufficient stiffness and strength. In the embodiment depicted, cam  120  and actuator  132  are made of a liquid crystal polymer such as Vectra™ LCP, and drive shaft  122  is made of a PPE+PS such as Noryl™. Drive shaft pin  126  and cam return spring  128  may be made of any suitable material, such as stainless steel. 
         [0072]    Cam  120  is retained between body portions  102   a  and  102   b , and in one embodiment, such as that depicted can reciprocate. Cam collar  136  has spaced apart, generally flat outer surfaces  142   a  and  142   b  tracks through which  140   a  and  140   b  are formed. These surfaces  140   a  and  140   b  are disposed between guide walls  144   a  and  144   b  formed in body portions  102   a  and  102   b . Cam collar  136  also includes oppositely facing channels  146   a  and  146   b  (see  FIG. 23 ), which are guided for axial reciprocation by guides  148   a  and  148   b  (not illustrated) formed in body portions  102   a  and  102   b , respectively. The upper end of shaft  134  and cross member  138  are disposed sandwiched between actuator halves  106   a  and  106   b . Each actuator half  106   a ,  106   b , includes a cam track  150  defined by a pair of spaced apart walls  150   a  and  150   b  extending from the interior surfaces of actuator halves  106   a  and  106   b . Cam track  150  is configured to receive and guide cross member  138  as actuator  106  is rotated about pin  114 , forcing cam  120  to advance linearly downwardly into body  102 . 
         [0073]    Drive shaft  122  includes annular collar  152  which is received in slots  154   a  and  154   b  (not illustrated) formed in body halves  102   a  and  102   b , respectively. Slots  154   a  and  154   b  rotatably support drive shaft  122 . Drive shaft  122  and cam  120  are generally aligned and collinear with each other, defining the axis of the shaft portion of body  102 . As cam  120  is advanced downwardly, drive shaft pin  126  follows cam tracks  140   a  and  140   b , causing drive shaft  122  to rotate, thus converting linear motion to rotary motion. Cam return spring  128  provides a nominal return force against cam collar  136 . 
         [0074]    Flexible shaft  124  is supported by a plurality of ribs  156 , formed in each body half  102   a ,  102   b , which support the bend in flexible shaft  124  that permits the rotary motion to be transferred to actuator  132  which is disposed at an angle relative to the shaft of body  102 . Flexible shaft  124  may be made of any suitable biocompatible material, such as stainless steel. In an embodiment depicted, flexible shaft  124  has a stranded construction, with a center core having multiple layers of wire wrapped thereabout. Ends  124   a  and  124   b  of flexible shaft  124  may be attached to end  122   b  and actuator  132 , respectively, in any suitable manner which sufficiently limits rotational end play to prevent or minimize lost rotational motion. In an embodiment depicted, end  124   a  was overmolded into end  122   b , and end  124   b  was press fit into actuator  132 . Alternatively, end  124   a  could be press fit into end  122   b , and end  124   b  overmolded into actuator  132 , both could be press fit, or both could be overmolded (with a corresponding change to the configuration of locator  104  to allow assembly. 
         [0075]    Referring to  FIGS. 21-25 , actuator  132  includes disc shaped member  158  and shaft  160  extending upwardly therefrom. The upper end of shaft  160  includes a pair of outwardly extending tabs  162   a  and  162   b . Locator  104  includes hub  164  defining bore  166  therethrough. Bore  166  is shaped to receive and rotatably support shaft  160 , and includes two outwardly extending arcuate recesses  168   a  and  168   b  configured to provide assembly clearance for tabs  162   a  and  162   b , allowing hub  164  to be inserted into bore  166 . The lengths of shaft  160  and hub  164  are sized such that tabs  162   a  and  162   b  are located above upper surface  164   a  of hub  164 , allowing rotation of actuator  132  while retaining it axially relative to hub  164 . Stops  170  and  170   b  extend upwardly from upper surface  164   a , limiting the rotation of actuator  132 . Bore  166  defines a central axis of locator  104  about which actuator  132  is rotated. The central axis of locator  104  is disposed at an angle to the axis of the shaft portion of body  102 , as previously mentioned. 
         [0076]    Hub  164  includes a pair of oppositely extending tabs  172   a  and  172   b  which retain port actuator  104  to body  102  and prevent rotation. Body halves  102   a  and  102   b  include respective recesses  174   a  (see  FIG. 21) and 174   b  (not illustrated) shaped complementarily to tabs  172   a  and  172   b.    
         [0077]    Referring also to  FIGS. 26 and 27 , disc shaped member  158  of actuator  132  is seen disposed within locator  104 . Actuator  132  includes a pair of spaced apart posts  176   a  and  176   b , extending from adjacent periphery  158   a  of member  158 . Posts  176   a  and  176   b  are shaped complementarily with openings  54 . In the embodiment depicted, the distal ends of posts  176   a  and  167   b  are tapered to assist in guiding posts  176   a  and  176   b  into openings  54 . Any suitable configuration may be utilized to create releasable contact between actuator  132  and actuator  12  capable of actuating actuator  12 . 
         [0078]    Disc shaped member  158  also includes a pair of spaced apart cams  178   a  and  178   b  which extend outwardly and upwardly from periphery  158   a  of member  158 .  FIG. 27  illustrates cam  178   a  at a cross-section taken near the bottom surface of member  158 . Cams  178   a  and  178   b  include ramps  180   a  and  180   b  which start at periphery  158   a  and lead out to surfaces  182   a  and  182   b , respectively. Each surface  182   a ,  182   b  is arcuate, shown in the embodiment depicted as generally having a constant radius. 
         [0079]    In the embodiment depicted, locator  104  includes a pair of spaced apart cantilever arms  184   a  and  184   b , each having rib  186   a  and  186   b , respectively. For clarity,  FIG. 27  illustrates arm  184   a  in cross-section taken through rib  186   a , at the same level as for cam  178   a . At their distal ends, arms  184   a  and  184   b  include respective inwardly extending flanges  188   a  and  188   b . Flanges  188   a  and  188   b  are shaped complementarily to recesses  56  on port body  8 , configured to engage ledges  56   a  when injection port  2  is retained by locator  104 . 
         [0080]    In the embodiment depicted, in the non-actuated state, posts  176   a  and  176   b  are generally aligned with arms  184   a  and  184   b , respectively, although posts  176   a  and  176   b  may be at any position that corresponds to position of the actuating feature of actuator  12 , which in the embodiment depicted is openings  54 . As actuator  106  is depressed, actuator  132  rotates (counterclockwise in the embodiment depicted when viewed from the bottom), advancing cams  178   a  and  178   b  such that ramps  180   a  and  180   b  contact ribs  186   a  and  186   b , respectively, deflecting arms  184   a  and  184   b  outwardly. When surfaces  182   a  and  182   b  engage ribs  186   a  and  186   b , arms  184   a  and  184   b  are deflected a distance sufficient to move flanges  188   a  and  188   b  to a position where they no longer extend into recesses  56  or contact ledges  56   a , thus releasing injection port  2  from locator  104 . 
         [0081]      FIG. 28  illustrates injection port  2  disposed in and retained by locator  104 , with extension housing  78  and tab  96  disposed in slots  110  and  112 , respectively (see  FIG. 20 , not seen in  FIG. 28 ). As depicted, posts  176   a  and  176   b  extend into openings  54  of actuator  12 , and flanges  188   a  and  188   b  extending into recesses  56  proximal ledges  56   a . Safety cap  80  is connected to injection port  12  when injection port  12  is inserted into locator  104 , covering fasteners  10  (not seen in  FIG. 28 ). 
         [0082]    Referring also to  FIGS. 20 and 22 , to insert injection port  2  into locator  104 , actuator  106  is oriented in the undeployed position so that actuator  132  is in the undeployed position. Actuator  12  is oriented in the undeployed position, and inserted into locator  104 , with extension housing  78  and tab  96  disposed in slots  110  and  112 , respectively. 
         [0083]    Actuator  106  may, as illustrated in  FIG. 20 , include a visual indicator to indicate whether actuator  106  is fully in the undeployed state, such as unlocked lock icon  190 , and indicia to indicate whether actuator  106  is in the deployed state, such as locked lock icon  192 . Such visual indication may be include by any suitable manner, such as by molding integral with actuator  106 , applying as a adhesive film or such, or printing directly on actuator  106 . With the indicator illustrated, unlocked lock icon  190  is visible adjacent the upper edge of body  102 , although other configurations of indication may be utilized, such as a window or such formed in body  102  to reveal the indicia. 
         [0084]    To use, locator  104  and a portion of  102 , if necessary, is inserted through an incision by the surgeon and located in the desired position adjacent the body tissue to which the medical implant (which in the embodiment depicted is an injection port  2 ) is to be attached. The angle between locator  104  and body  102  allows the surgeon to visualize the site directly. With injection port  2  in position, the one or more fasteners  10  are moved from the undeployed position to the deployed position in an annular path to engage the tissue. Fasteners  10  allow injection port  2  to be secured to the tissue with a retention strength equal to or greater than when secured with sutures. Safety switch  108  is rotated about pivot pin  118 , withdrawing lockout tab  194  from lower opening  196 , allowing actuator  106  to be rotated about pivot pin  114 . This action causes cam track  150  to move cross member  138  downward, causing cam collar  136  to rotate drive shaft  122 , thereby rotating actuator  132  relative to locator  104 . 
         [0085]    Rotation of actuator  132  actuates actuator  12  by rotating it. The engagement between extension  78  and tab  96  and slots  110  and  112 , respectively, prevent port body  8  from rotating, allowing relative motion between actuator  12  and port body  8 . 
         [0086]    Once actuator  106  reaches the deployed position, lockout tab  194  is urged into upper opening  198 , retaining actuator  106  in the deployed position. In the embodiment depicted, spring  130  biases lockout tab  194  sufficiently to produce sound as lockout tab  194  snaps into upper opening  198 , providing an audible signal that actuator  106 , and therefore actuator  12  and fasteners  10  are deployed fully. As illustrated in  FIG. 29 , with actuator  106  in the deployed position, actuator  12  has been rotated and fasteners  10  are in the deployed position having penetrated the body tissue, such as the rectus sheath. Cams  178   a  and  178   b  have been rotated to a position where surfaces  182   a  and  182   b  are adjacent ribs  186   a  and  186   b , with arms  184   a  and  184   b  deflected outwardly such that flanges  188   a  and  188   b  are not disposed in recesses  56  and not engaging ledges  56   a . With injection port  2  secured to the body tissue, and released from locator  104 , the surgeon may withdraw locator  104 , leaving injection port  2  in place. If a visual indicator of the state of the attachment mechanism is included with the implant, the surgeon can tell whether the attachment mechanism is fully deployed. 
         [0087]    The attachment mechanism embodied in injection port  2  is configured to be reversible so that the medical implant, injection port  2 , may be moved, such as to reposition it or remove it from the patient. To do so, with actuator  106  in the deployed position, locator  104  is placed over injection port  2 , locating extension  78  and tab  96  in slots  110  and  112  so that posts  176   a  and  176   b  are engaged with recesses  54 . Safety switch  108  is rotated to withdraw lockout tab  194  from upper opening  198 , while the surgeon pulls up on extension  200  of actuator  106 . Although cam return spring  128  urges cam collar  136  upwardly, extension  200  allows an additional return force to be applied. As cross member  138  is pulled up by cam track  150 , actuator  132  rotates actuator  12 , moving fasteners  10  from the deployed position to the undeployed position simultaneously, while cams  178   a  and  178   b  disengage from ribs  186   a  and  186   b , allowing flanges  188   a  and  188   b  to engage recess  56  and ledge  56   a  so as to retain injection port  2  in locator  104 . When actuator  106  has been moved to the undeployed position, lockout tab  194  snaps into lower opening  196 , generating an audible signal that actuator  106  is undeployed fully, and injection port  2  is detached from the body tissue and may be relocated or removed. 
         [0088]    In  FIG. 30 , adjustable gastric band  210  is shown wrapped around an upper portion of stomach  212 , kept in place by attaching the two ends together and extending portion  214  of the stomach  212  over adjustable gastric band  210  by suturing portion  214  to the stomach. One end of flexible conduit  216  is in fluid communication with the internal cavity of the balloon (not shown), with the other end being in fluid communication with an internal cavity of injection port  218 . At the time adjustable gastric band  210  is implanted around a portion of the stomach, remote injection port  218  is also implanted at a suitable location, usually within the rectus sheaths, for transcutaneous access via a Huber needle. 
         [0089]    In summary, numerous benefits have been described which result from employing the concepts of the invention. The foregoing description of one or more embodiments of the invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed. Modifications or variations are possible in light of the above teachings. The one or more embodiments were chosen and described in order to illustrate the principles of the invention and its practical application to thereby enable one of ordinary skill in the art to utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the claims submitted herewith.