Applier with safety for implantable medical device

An attachment mechanism for a surgically implantable medical device includes one or more fasteners which may be simultaneously moved from an undeployed position to a deployed position by operation of an integral actuator. The attachment mechanism may be configured to be deactuated, and the fasteners simultaneously moved from a deployed position to an undeployed position, allowing removal or repositioning of the medical device. An applier includes a locator for detachably holding the implantable medical device, locating it at the desired position, and actuating the attachment mechanism. The applier is configured to undeploy the attachment mechanism the implantable medical device can be detached from the body tissue.

This application incorporates by reference the following U.S. patent applications, all of which were filed on filed Dec. 19, 2003: application Ser. No. 10/741,127 titled Subcutaneous Injection Port For Applied Fasteners; application Ser. No. 10/10.741,875 titled Subcutaneous Self Attaching Injection Port With Integral Moveable Retention Members; and application Ser. No. 10/741,868 titled Subcutaneous Self Attaching Injection Port With Integral Fasteners.

TECHNICAL FIELD

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

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.

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.

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

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.

Referring toFIGS. 1-5, there is shown an implantable medical device, more specifically an injection port, generally indicated at2, 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 port2, 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.

Injection port2includes septum retainer4, septum6and port body8. Injection port2, with the integrally constructed attachment mechanism, also includes one or more fasteners10, actuator12and a plurality of link members14.

As seen inFIG. 4, septum6, which may be made of any biocompatible material such as silicone, is disposed partially within internal cavity16of septum retainer4, adjacent annular flat18. Septum retainer4, port body8, and actuator12may be made of any suitable biocompatible material having sufficient stiffness and strength, such as polyetheretherketon (known as PEEK). Fasteners10and link members14may be made of any suitable biocompatible material, such as stainless steel.

Port body8includes annular rim20, which engages the upper surface of septum6about an annular portion. Port body8is retained to septum retainer4by a plurality of pins22which are disposed through respective holes24formed in recesses24ain port body8and which extend inwardly into respective recesses26formed about the bottom periphery of septum retainer4. Pins22may be made of any suitable biocompatible material, such as stainless steel.

The uncompressed height of septum6is approximately 5 mm around the outer diameter and the uncompressed diameter is approximately 18 mm. The exposed diameter for access to reservoir20is approximately 14 mm. The distance between the lower surface of annular rim20and annular flat18is approximately 4 mm, such that septum6is compressed approximately 20% to be adequately self healing to maintain a fluid tight system under pressure and still allow a low profile.

Plate28is disposed in recess16aformed in the bottom of septum retainer4, underlying septum6and fluid chamber or reservoir30. As seen inFIG. 4, plate28does not contact sidewall16b. In the embodiment depicted, plate28is metallic, such as stainless steel. When a needle is inserted through septum6to introduce or withdraw fluid from fluid chamber30, such as in order to adjust the size of an adjustable gastric band, metallic plate28will protect septum retainer4from puncture and provide tactile feedback to the surgeon through the needle indicating that the needle has bottomed in reservoir30. Plate28may be secured to septum retainer4in any suitable manner. In the embodiment depicted, plate28is held in place by retaining lip4aextending over the periphery of plate28as best seen inFIGS. 4,28and29. Initially, retaining lip4aextends upwardly as an annular lip, providing clearance for insertion of plate28into the recess at the bottom of septum retainer4, and retaining lip4ais then rolled or otherwise deformed to overlie at least a portion of the periphery of plate28thereby retaining plate28. In the embodiment depicted the diameter of recess16ais smaller than the diameter of sidewall16b, providing room to form the annular lip and to deform it into retaining lip4a. Plate28could be insert molded, with retaining lip4amolded as illustrated.

Septum retainer4includes passageway32, in fluid communication with fluid chamber30, which is defined by fitting34extending from the periphery adjacent the bottom of retainer4. Tube36, which in the embodiment depicted, leads to an adjustable gastric band (not shown), is connected to fitting34, being compressingly urged against annular rib38by connector40, which is disposed about tube36and secured to port body8as described below. Sleeve42is disposed about tube36, secured to connector40by annular ribs44. Sleeve42relieves strain on tube36, preventing tube36from kinking when loaded laterally.

Actuator12is secured to port body8. Although in the embodiment depicted actuator12is illustrated as an annular ring rotatably supported by port body8, actuator12may be any suitable configuration and supported in any suitable manner to permit actuator12to function to move fasteners10between and including deployed and undeployed positions. As seen inFIG. 5, port body8includes a plurality of downwardly and outwardly extending tabs46. In the embodiment depicted, there are four equally spaced tabs46. Actuator12includes an equal number of corresponding recesses48, each having arcuate bottom50. To assemble actuator12to port body8, recesses48are aligned with tabs46, and pushed down, temporarily deflecting tabs46inwardly until tabs46reach recesses48and move outwardly to dispose lower edges46ain recesses48such that actuator is retained thereby. The lengths of tabs46and depth of recesses48allow some axial end play between actuator12and port body8, as will be described below.

Actuator12may rotate generally about the central axis of port body8. In the embodiment depicted, actuator12may rotate through an angle of about 40 degrees, although any suitable angle may be used. In the embodiment depicted, when actuator12is rotated in the deploying direction, causing fasteners10to move to the deployed position, rotation of actuator12beyond the fully deployed position is limited by end48ccontacting tab46.

A detent system is formed by a pair of spaced apart raised detent ribs48a,48bextending inwardly from the wall of each recess48, and a corresponding raised rib46bextending outwardly from tab46. The detent system assists in preventing actuator12from rotation and fasteners10from moving out of fully retracted or fully extended fired states under vibration or incidental loads, as described below.

Actuator12includes a plurality of spaced apart openings or slots54, which may be engaged by any suitable instrument to transmit the necessary torque to actuator12to extend fasteners10to the actuated position. Slots54are configured to be engaged by commercially available instruments, rectangular in the embodiment depicted, or by the dedicated applier described below. Port body6includes a plurality of recesses56disposed about its lower periphery which are configured to cooperate with the dedicated applier as described below.

Referring also toFIGS. 6 and 7, septum retainer4includes a plurality of locating tabs58extending outwardly from adjacent the bottom periphery of septum retainer4. Locating tab58amay be integral with fitting34. Tabs58and58aare located in respective complementarily shaped recesses60formed in the inner surface of port body8, aligning septum retainer4properly with port body8.

FIG. 6illustrates fasteners10in the retracted position. As can be seen, fasteners10are disposed in respective recesses or slots60formed in port body8.FIG. 7illustrates fasteners10in the extended, or fired, position, extending from slots60. Rotation of actuator12moves fasteners10from the retracted position to the extended position.

FIGS. 8-11are a series of figures illustrating the operation of actuator12and one of the plurality of fasteners10, it being understood that the operation on one of fasteners10may be the same as for all fasteners10, which may, in one embodiment, be moved from a deployed position to an undeployed position simultaneously.FIG. 8illustrates fastener10in a fully retracted state, the undeployed position, disposed completely within slot62such that sharp tip64is not exposed. This prevents tip64from accidentally sticking the surgeon or penetrating any object. Actuator12is illustrated rotated counter clockwise as far as permitted by recesses48and tabs46. In this position, ribs46bare disposed clockwise of ribs48b, as seen inFIG. 14. First ends14aof link members14are rotatably carried by actuator12, spaced apart at positions corresponding to the positions of fasteners10. Second ends14bare disposed within openings66of fasteners10.

To actuate the attachment mechanism, integral actuator12is 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 rib46bpasses rib48b, which may produce an audible signal in addition to a tactile signal to the surgeon. Second end14bof link member14is free to move within slot66during actuation, as the force that rotates fastener10into the extended position is transmitted to fastener10through the interaction between cam surface68of fastener10and actuating cam surface70of actuator12. As actuator12rotates clockwise, actuating cam surface70engages and pushes against cam surface68, rotating fastener10about pivot pin22. The majority of the force from actuating cam surface70acts tangentially on cam surface68, off center relative to pivot pin22, causing fastener10to rotate. During actuation, end14bof link member14remains free to move within slot66, applying no driving force to rotate fastener10.

InFIG. 9, fastener10is rotated about half way though its range of rotation, about 90 degrees as a result of the clockwise rotation of actuator12. As actuator12is rotated clockwise, the force between actuator cam surface70and cam surface68causes actuator12to move upward slightly as allowed by the tolerancing of the components. As actuator12is rotated further clockwise from the position shown inFIG. 9, actuator cam surface70continues to engage and push against cam surface68, rotating fastener10further counterclockwise.

InFIG. 10, actuator12is rotated clockwise to its fullest extent, with rib46bhaving been urged past detent rib48a(seeFIG. 15). In this position, fastener10has rotated to its fullest extent, almost 180 degrees in the embodiment illustrated, with tip64disposed within recess62. In this position, actuator cam surface70is over center, and actuator12is resistant to being back driven by an undeploying force imparted to fastener10as cam surface68acts against actuator cam surface70in a direction that tends to push actuator12up instead of rotating actuator12. The distal end portion of fastener10is configured essentially as a beam, depicted as having a generally rectangular cross section along its length, tapering to sharp tip64. With fastener10extending approximately 180 degrees in the fully extended state, the deployed position, forces which might act on fasteners10tend to act through the pivot axis defined by pivot pin22, instead of rotating fasteners10. It is noted that although pin22is illustrated as being a separate piece from fastener10, the two may be integral or even of unitary construction.

If it is desirable to retract fasteners10, such as to remove or reposition the implanted device, actuator12may be rotated in an undeploying direction, counterclockwise in one embodiment depicted. Starting with the position of actuator12shown inFIG. 10, actuator12may be rotated counterclockwise, with actuator cam surface70sliding against cam surface68, without rotating fastener10. In the embodiment depicted, continued counterclockwise rotation of actuator12moves cam surface70out of contact with cam surface68, with no substantial rotating force being exerted on fastener10until second end14bof link member reaches a location in slot66, such as at one end of slot66, at which link member14begins pulling against slot66causing fastener10to rotate and begin to retract.

As seen inFIG. 11, actuator12has been advanced counterclockwise compared to the position shown inFIG. 10, and fastener10is rotated approximately halfway through its range. As can be seen by comparingFIG. 9toFIG. 11, actuator12is in different positions with fastener10in 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 member14is pulling on slot66in comparison to actuator cam surface70pushing directly on cam surface68. To retract fasteners10fully, actuator12is rotated until detent rib46bsnaps past detent rib48b.

Referring toFIG. 8, when fasteners10reach the fully undeployed position tip64may be disposed fully in slot or recess62. Further undeploying rotation of actuator12is prevented by link member14which is prevented from further movement by fastener10.

Referring toFIGS. 2 and 3, actuator12includes openings52aformed therethrough, which align with corresponding openings52bformed in port body8when actuator is in the undeployed position. Openings52aand52bmay be used by the surgeon to suture injection port2if the integral attachment mechanism is not used.

Referring toFIGS. 12 and 13, the attachment mechanism is shown without actuator12. Link members14are shown in their actual positions when first ends14aare supported by actuator12, in the deployed and in the undeployed states.

Referring toFIGS. 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 port2. InFIG. 14, the attachment mechanism is in the retracted, undeployed state or position. In this position, detent rib46bis clockwise of detent rib48b, and thus in the undeployed detent position. InFIG. 15, the attachment mechanism is in the actuated or deployed position. In this position, detent rib46bis counterclockwise of detent rib48b, and thus in the deployed detent position.

FIGS. 14 and 15illustrate a visual indicator of the state of the attachment mechanism. As seen inFIG. 14, indicia may be utilized, such as an unlocked lock icon72and a locked lock icon74molded integral with actuator ring12. Any suitable graphic indicator may be used, and may be printed on or otherwise applied in a suitable manner. Port body6may include indicator76to provide a reference point for the movable indicia. Arrow78may be included to indicate the bidirectional motion of actuator12.

FIGS. 16-18illustrate the locking connection between connector40and port body6.FIG. 16is an exploded perspective view showing fitting34partially surrounded by extension78.FIG. 17shows extension78in cross-section, with connector40generally disposed about fitting34and tube36aligned in circumferential slot78cof extension78. Connector40includes a pair of tabs40a,40b, extending outwardly therefrom. To assemble, connector40is guided along tube36and fitting34, with tabs40aand40baligned with openings78aand78bof extension78. With tabs40aand40baligned with circumferential slot78c, connector40is rotated to lock it in place. During rotation, detent edge78dcreates interference opposing the rotation of tab40a, but is dimensioned to allow tab40ato be rotated past, to the locked position seen inFIG. 18.

FIG. 19illustrates safety cap80which may be removably secured to the bottom of injection port2to cover fasteners10to protect users from accidental exposure to sharp tips64while handling injection port2. Safety cap80includes body82with annular rim84and raised center86defining annular recess88. Safety cap80may be oriented and retained to injection port through any suitable configuration. As depicted, body82includes a plurality of arcuate retention tabs90extending upwardly from raised center86. Arcuate retention tabs90are shaped complementarily to corresponding arcuate slots92, best seen inFIGS. 3,6and7, and may have ribs as shown. Safety cap80is secured to injection port2by inserting arcuate retention tabs90into arcuate slots92, which are sized to retain tabs90. Fasteners10are thus aligned with annular recess88, which is sized to allow fasteners10to be extended without contacting safety cap80. As depicted, since arcuate retention tabs90and arcuate slots92are respectively the same size and equally spaced, safety cap80is not indexed to a particular position, and may be secured to injection port2in four different positions. Safety cap80includes pull tab94with raised a plurality of ribs96to provide a better gripping surface. Although pull tab94may be oriented in any suitable orientation, in the embodiment, the relative position between pull tab94and arcuate retention tabs90locates pull tab at 45 degrees to the direction of connector40. Tabs90and slots92may be of any suitable shape.

As mentioned previously, the attachment mechanism may be actuated by engaging slots54with commercially available instruments or by a dedicated applier.FIG. 20illustrates applier, generally indicated at100, which is configured to position, actuate, deactuate, remove or reposition injection port2. 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.

As shown inFIG. 20, applier100includes body102, locator104, actuator106and safety switch108. As will be described below, injection port2may be assembled to locator104, with extension78and tab96disposed in alignment slots110and112. Locator104is angled relative to body102, allowing for easier and better visualization of injection port2during implantation. In the embodiment depicted, the angle is 20 degrees and the shaft portion of body102is 10 cm.

Referring toFIG. 21, body102includes first and second halves102aand102bassembled to each other to contain the internal components. Except for locating pins202, pivot pins114and ship laps, body halves102aand102bare substantially similar to each other. Locating pins202, illustrated as extending from body half102a, fit into respective complementarily shaped openings (not illustrated) on body half102b. The engagement of the plurality of locating pins202in the openings is sufficient to hold body halves102aand102btogether. Pins202may alternatively extend from body half102bwith the openings carried by body half102a. Any suitable configuration may be used to assemble and secure body halves102aand102btogether.

Actuator106includes first and second halves106aand106b. Locating pins204, illustrated as extending from actuator half106a, fit into respective complementarily shaped openings (not illustrated) on actuator half106b. Pins204may alternatively extend from actuator half106bwith the openings carried by actuator half106a. Any suitable configuration may be used to assemble and secure actuator halves106aand106btogether. Body half102bincludes pivot pin114bwhich rotatably supports actuator106at one end, extending through pivot holes116aand116binto opening114a. Body half102aincludes pivot pin118b(seeFIG. 22) which rotatably supports safety switch108. Body halves102aand102b, locator104, actuator halves106aand106b, and safety switch108may be made of any biocompatible material such as polycarbonate.

Referring toFIGS. 21-24, applier100includes cam120, drive shaft122with flexible shaft124, drive shaft pin126, cam return spring128, safety biasing spring130, and actuator132. Actuator132is configured to effect the deployment or undeployment of the attachment mechanism of the medical implant. Cam120includes shaft134and cam collar136. The upper end of shaft134has a “T” configuration terminating in cross member138. Cam collar136defines a hollow interior and a pair of spaced apart, complementarily shaped cam tracks140aand140bformed on opposite sides of cam collar136. Upper end122aof drive shaft122is disposed partially within the hollow interior defined by cam collar136, captured therein by drive shaft pin126. Drive shaft pin126is sized such that each end is located within a respective cam track140a,140b. The length of the hollow interior allows upper end122ato reciprocate therein, with cam tracks140aand140bimparting rotation to drive shaft122through drive shaft pin126during reciprocation. Cam120, drive shaft122and actuator132may be made of any suitable material having sufficient stiffness and strength. In the embodiment depicted, cam120and actuator132are made of a liquid crystal polymer such as Vectrat™ LCP, and drive shaft122is made of a PPE+PS such as Norylt™. Drive shaft pin126and cam return spring128may be made of any suitable material, such as stainless steel.

Cam120is retained between body portions102aand102b, and in one embodiment, such as that depicted can reciprocate. Cam collar136has spaced apart, generally flat outer surfaces142aand142btracks through which140aand140bare formed. These surfaces140aand140bare disposed between guide walls144aand144bformed in body portions102aand102b. Cam collar136also includes oppositely facing channels146aand146b(seeFIG. 23), which are guided for axial reciprocation by guides148aand148b(not illustrated) formed in body portions102aand102b, respectively. The upper end of shaft134and cross member138are disposed sandwiched between actuator halves106aand106b. Each actuator half106a,106b, includes a cam track150defined by a pair of spaced apart walls150aand150bextending from the interior surfaces of actuator halves106aand106b. Cam track150is configured to receive and guide cross member138as actuator106is rotated about pin114, forcing cam120to advance linearly downwardly into body102.

Drive shaft122includes annular collar152which is received in slots154aand154b(not illustrated) formed in body halves102aand102b, respectively. Slots154aand154brotatably support drive shaft122. Drive shaft122and cam120are generally aligned and collinear with each other, defining the axis of the shaft portion of body102. As cam120is advanced downwardly, drive shaft pin126follows cam tracks140aand140b, causing drive shaft122to rotate, thus converting linear motion to rotary motion. Cam return spring128provides a nominal return force against cam collar136.

Flexible shaft124is supported by a plurality of ribs156, formed in each body half102a,102b, which support the bend in flexible shaft124that permits the rotary motion to be transferred to actuator132which is disposed at an angle relative to the shaft of body102. Flexible shaft124may be made of any suitable biocompatible material, such as stainless steel. In an embodiment depicted, flexible shaft124has a stranded construction, with a center core having multiple layers of wire wrapped thereabout. Ends124aand124bof flexible shaft124may be attached to end122band actuator132, respectively, in any suitable manner which sufficiently limits rotational end play to prevent or minimize lost rotational motion. In an embodiment depicted, end124awas overmolded into end122b, and end124bwas press fit into actuator132. Alternatively, end124acould be press fit into end122b, and end124bovermolded into actuator132, both could be press fit, or both could be overmolded (with a corresponding change to the configuration of locator104to allow assembly.

Referring toFIGS. 21-25, actuator132includes disc shaped member158and shaft160extending upwardly therefrom. The upper end of shaft160includes a pair of outwardly extending tabs162aand162b. Locator104includes hub164defining bore166therethrough. Bore166is shaped to receive and rotatably support shaft160, and includes two outwardly extending arcuate recesses168aand168bconfigured to provide assembly clearance for tabs162aand162b, allowing hub164to be inserted into bore166. The lengths of shaft160and hub164are sized such that tabs162aand162bare located above upper surface164aof hub164, allowing rotation of actuator132while retaining it axially relative to hub164. Stops170and170bextend upwardly from upper surface164a, limiting the rotation of actuator132. Bore166defines a central axis of locator104about which actuator132is rotated. The central axis of locator104is disposed at an angle to the axis of the shaft portion of body102, as previously mentioned.

Referring also toFIGS. 26 and 27, disc shaped member158of actuator132is seen disposed within locator104. Actuator132includes a pair of spaced apart posts176aand176b, extending from adjacent periphery158aof member158. Posts176aand176bare shaped complementarily with openings54. In the embodiment depicted, the distal ends of posts176aand167bare tapered to assist in guiding posts176aand176binto openings54. Any suitable configuration may be utilized to create releasable contact between actuator132and actuator12capable of actuating actuator12.

Disc shaped member158also includes a pair of spaced apart cams178aand178bwhich extend outwardly and upwardly from periphery158aof member158.FIG. 27illustrates cam178aat a cross-section taken near the bottom surface of member158. Cams178aand178binclude ramps180aand180bwhich start at periphery158aand lead out to surfaces182aand182b, respectively. Each surface182a,182bis arcuate, shown in the embodiment depicted as generally having a constant radius.

In the embodiment depicted, locator104includes a pair of spaced apart cantilever arms184aand184b, each having rib186aand186b, respectively. For clarity,FIG. 27illustrates arm184ain cross-section taken through rib186a, at the same level as for cam178a. At their distal ends, arms184aand184binclude respective inwardly extending flanges188aand188b. Flanges188aand188bare shaped complementarily to recesses56on port body6, configured to engage ledges56awhen injection port2is retained by locator104.

In the embodiment depicted, in the non-actuated state, posts176aand176bare generally aligned with arms184aand184b, respectively, although posts176aand176bmay be at any position that corresponds to position of the actuating feature of actuator12, which in the embodiment depicted is openings54. As actuator106is depressed, actuator132rotates (counterclockwise in the embodiment depicted when viewed from the bottom), advancing cams178aand178bsuch that ramps180aand180bcontact ribs186aand186b, respectively, deflecting arms184aand184boutwardly. When surfaces182aand182bengage ribs186aand186b, arms184aand184bare deflected a distance sufficient to move flanges188aand188bto a position where they no longer extend into recesses56or contact ledges56a, thus releasing injection port2from locator104.

Referring also toFIGS. 20 and 22, to insert injection port2into locator104, actuator106is oriented in the undeployed position so that actuator132is in the undeployed position. Actuator12is oriented in the undeployed position, and inserted into locator104, with extension housing78and tab96disposed in slots110and112, respectively.

Actuator106may, as illustrated inFIG. 20, include a visual indicator to indicate whether actuator106is fully in the undeployed state, such as unlocked lock icon190, and indicia to indicate whether actuator106is in the deployed state, such as locked lock icon192. Such visual indication may be include by any suitable manner, such as by molding integral with actuator106, applying as a adhesive film or such, or printing directly on actuator106. With the indicator illustrated, unlocked lock icon190is visible adjacent the upper edge of body102, although other configurations of indication may be utilized, such as a window or such formed in body102to reveal the indicia.

To use, locator104and a portion of102, 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 port2) is to be attached. The angle between locator104and body102allows the surgeon to visualize the site directly. With injection port2in position, the one or more fasteners10are moved from the undeployed position to the deployed position in an annular path to engage the tissue. Fasteners10allow injection port2to be secured to the tissue with a retention strength equal to or greater than when secured with sutures. Safety switch108is rotated about pivot pin118, withdrawing lockout tab194from lower opening196, allowing actuator106to be rotated about pivot pin114. This action causes cam track150to move cross member138downward, causing cam collar136to rotate drive shaft122, thereby rotating actuator132relative to locator104.

Once actuator106reaches the deployed position, lockout tab194is urged into upper opening198, retaining actuator106in the deployed position. In the embodiment depicted, spring130biases lockout tab194sufficiently to produce sound as lockout tab194snaps into upper opening198, providing an audible signal that actuator106, and therefore actuator12and fasteners10are deployed fully. As illustrated inFIG. 29, with actuator106in the deployed position, actuator12has been rotated and fasteners10are in the deployed position having penetrated the body tissue, such as the rectus sheath. Cams178aand178bhave been rotated to a position where surfaces182aand182bare adjacent ribs186aand186b, with arms184aand184bdeflected outwardly such that flanges188aand188bare not disposed in recesses56and not engaging ledges56a. With injection port2secured to the body tissue, and released from locator104, the surgeon may withdraw locator104, leaving injection port2in 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.

The attachment mechanism embodied in injection port2is configured to be reversible so that the medical implant, injection port2, may be moved, such as to reposition it or remove it from the patient. To do so, with actuator106in the deployed position, locator104is placed over injection port2, locating extension78and tab96in slots110and112so that posts176aand176bare engaged with recesses54. Safety switch108is rotated to withdraw lockout tab194from upper opening198, while the surgeon pulls up on extension200of actuator106. Although cam return spring128urges cam collar136upwardly, extension200allows an additional return force to be applied. As cross member138is pulled up by cam track150, actuator132rotates actuator12, moving fasteners10from the deployed position to the undeployed position simultaneously, while cams178aand178bdisengage from ribs186aand186b, allowing flanges188aand188bto engage recess56and ledge56aso as to retain injection port2in locator104. When actuator106has been moved to the undeployed position, lockout tab194snaps into lower opening196, generating an audible signal that actuator106is undeployed fully, and injection port2is detached from the body tissue and may be relocated or removed.

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.