ENHANCED STABILITY IMPLANTABLE MEDICAL DEVICE
An implantable medical device is provided which has a housing of an elongate form to minimize a size of an incision required for implantation. A stabilizing element is associated with the elongated form housing for the medical device. The stabilizing element transitions from a low profile initial form to a higher width final form to provide the medical device with a stabilized footprint after implantation. The stabilizing element is in the form of a rotating wing in one embodiment. In another embodiment, the stabilizing element is in the form of an expanding loop that can bend to extend out of side openings of a cavity within the housing, to provide such stabilization at the implantation site. The medical device can be in the form of a pacemaker, infusion pump, vascular access port or other subcutaneously implanted medical device.
This application is a continuation of U.S. patent application Ser. No. 12/287,398, filed on Oct. 8, 2008 and issued as U.S. Pat. No. 8,209,015 on Jun. 26, 2012, which claims benefit under Title 35, United States Code §119(e) of U.S. Provisional Application No. 60/960,640 filed on Oct. 9, 2007.
FIELD OF THE INVENTIONThe following invention relates to medical devices which are implanted subcutaneously to provide a therapeutic benefit for a patient at the implantation site. More particularly, this invention relates to subcutaneously implanted medical devices which have a low profile form for minimally invasive implantation through a small incision, but which can be adjusted in form to have a highly stable configuration after implantation to resist movement after implantation. Such medical devices could be in the form of pacemakers, infusion devices, such as infusion pumps, vascular access ports, or other medical devices which are taught in the prior art to be implanted subcutaneously to provide a therapeutic benefit within a patient.
BACKGROUND OF THE INVENTIONA variety of medical conditions have been identified where implantation of a medical device is indicated. Such medical devices can include pacemakers, infusion pumps, vascular access ports, nerve stimulators, spinal stimulators, etc. Each of these medical devices generally include some form of housing which at least partially contains portions of the medical device apparatus to isolate this medical device apparatus from bodily fluids or bodily structures outside of the housing. Furthermore, typically some form of interface extends out of the housing to interact with surrounding bodily systems. For instance, in the case of a pacemaker electrodes extend from the housing as electrical leads which are coupled to nerves of the heart which, when receiving electrical stimulus from the pacemaker, cause the heart to beat. Infusion pumps include an outlet tube passing into a location where the preparation being infusion is to be delivered. For instance, if the infusion pump is infusing a pain medication, it would typically be implanted into a vascular structure, such as into a vein of the patient.
With such prior art medical devices, such implantation has required that the medical device be configured and positioned in a way that keeps the medical device stationary within the body. Such configuration has generally involved shaping the devices to be generally flat and either circular or square/rectangular in form (viewed from above). “Twiddlers Syndrome” refers to a situation where a subcutaneous medical device has been manipulated by the patient (or sometimes spontaneously) and flipped over upon itself one or more times, so that the device function is adversely affected. This can lead to fracture of output devices and potential failure of the medical device.
The shape of these medical devices requires that a relatively large incision be made to pass the medical device through the skin during surgical implantation of the medical device. As the size of the incision increases, the difficulty associated with hiding the incision from visual detection by others is increased. Generally, patients appreciate having small incisions when medical devices are to be implanted. With known prior art technology of the shape described above, such incisions have not been minimized. To some extent electronics and other components within a housing of the medical device can be miniaturized to minimize a size of the medical device and hence the required incision. However, such miniaturization has limits and other complications are associated with such miniaturization including enhanced cost and potentially reduced battery life, reduced storage capacity for medical preparations to be delivered and other potentially adverse effects. Accordingly, a need exists for a way to configure a medical device so that it can maintain fully beneficial operation while facilitating implantation through a reduced size incision. A solution to this problem would beneficially also be at least as resistant to “Twiddlers Syndrome” as prior art medical devices.
SUMMARY OF THE INVENTIONWith this invention an implantable medical device is provided which can be implanted through a relatively small incision and yet maintain full stability at the implantation site. The medical device includes a housing which has an elongate form. This elongate form is defined by a long axis extending between front and rear ends thereof and a lateral axis extending between lateral sides of the housing. The long axis is longer than the lateral axis, and typically at least about twice as long as the lateral axis.
Equipment within the housing for the medical device is configured as appropriate to fit within this elongate housing, rather than in prior art housings which are generally either circular in form or rectangular/square in form. With such an elongate form, it is only necessary that an incision be provided large enough to allow the passage of the lateral cross-section of the housing, perpendicular to the long axis, to pass through the incision. For instance, if the housing is two inches long, one-half inch wide and one-half inch high, an incision of one-half inch in length (or slightly greater) is sufficient to allow passage of the housing of the medical device therethrough.
Furthermore, a stabilizing element is associated with the housing. This stabilizing element has both an elongate narrow form and a deployed wide lateral form to enhance stability of the housing and hence the entire medical device at the implantation site. This stabilizing element can be in the form of one or more wings pivotably attached to the housing. These wings have an elongate form between ends thereof with these ends aligned with the long axis of the housing during implantation. After the housing and wing have arrived at the implantation site, the wing can be rotated so that the ends thereof extend laterally away from lateral sides of the housing to stabilize the medical device. Once so stabilized, the medical device has just as much (or more) stability at the implantation site as it would have if it was not provided with this particularly elongate form. Hence, a small incision has been facilitated without any adverse impact on functionality of the medical device.
In another form, this stabilizing element is in the form of a separate loop and the housing is provided with a cavity therein with a rear opening and at least one (and preferably two) lateral side opening. The loop is routed through the rear opening and then is caused to expand within the cavity to expand out the at least one side opening to provide enhanced stability to the medical device. The loop can be bent within the cavity to extend laterally out of the side openings to stabilize the housing. Alternatively, the loop can be formed of a resilient material which is initially restrained into an elongate form aligned with the long axis of the housing, but which springs to a natural original form after passing into the cavity where portions of the loop extend out the lateral side openings of the cavity, to stabilize the housing after the loop has been inserted entirely within the cavity.
OBJECTS OF THE INVENTIONAccordingly, a primary object of the present invention is to provide a medical device which can pass through a reduced size incision while maintaining stability at an implantation site subcutaneously within the body of a patient.
Another object of the present invention is to provide a medical device which can be implanted into a subcutaneous implantation site within the body of a patient.
Another object of the present invention is to provide a method for implanting a medical device and stabilizing the medical device once implanted.
Another object of the present invention is to provide a subcutaneous implantable medical device which has a small cross-section for implantation through a small incision which maintains high stability once implanted.
Another object of the present invention is to provide a medical device which can morph between a smaller profile implantation form and a larger profile static implanted form after being implanted at an implantation site.
Another object of the present invention is to provide a pacemaker which can be implanted through a small incision and still maintain stability once implanted.
Another object of the present invention is to provide a medical device which can be stabilized after implantation with the stabilization process easily and reliably performed by a medical professional.
Other further objects of the present invention will become apparent from a careful reading of the included drawing figures, the claims and detailed description of the invention.
Referring to the drawings, wherein like reference numerals represent like parts throughout the various drawing figures, reference numeral 10 (
In essence, and with particular reference to
More specifically, and with continuing reference to
The housing 20 generally includes a perimeter 22 including opposite ends 24 and opposite sides 26 extending between the ends 24. The housing 20 also includes a bottom 25 spaced from a top. The housing 20 in this preferred embodiment generally has a constant cross-section size between the bottom 25 and the top and preferably a thickness between the bottom 25 and the top that is similar to a width between the sides 26. The ends 24 and sides 26 are preferably substantially planar, but can be somewhat rounded if desired.
Importantly, the housing 20 exhibits an elongate form so that the ends 24 are spaced further from each other than a spacing between the sides 26 and a spacing between the bottom 25 and the top. Most preferably, this amount of elongation is such that a length of the housing 20 along a long axis between the ends 24 is at least about twice as great as a length of a lateral axis extending between the sides 26. The housing 20 can exhibit a greater degree of elongation with the length between the ends 24 more than twice as great as a width between the sides 26, or slightly less than this preferred amount and still benefit from the concept of this invention.
The pacemaker 10 is shown with an axle 30 extending down from the bottom 25 of the housing 20 perpendicular to the long axis and perpendicular to the lateral axis of the housing 20. While this axle 30 is not strictly required, it is beneficially provided to allow for pivotable attachment of the wing 40 to the bottom 25 of the housing 20. As an alternative to the separate axle 30, an axle-like structure can be formed into the housing 20 or the wing 40 to cooperate with a hole in the housing 20 or the wing 40. When the axle 30 is utilized, it fits within an appropriate cylindrical hole extending into the bottom 25 of the housing 20 and through the wing 40. This axle 30 is preferably cylindrical in form and has a length merely sufficient to extend a distance similar to a thickness of the wing 40.
With continuing reference to
Most preferably, the wing 40 has a perimeter size slightly less than the perimeter 22 of the housing 20. As an alternative, the wing 40 could be precisely the same perimeter size as the housing 20 or could be slightly larger than a perimeter 22 of the housing 20 and still function adequately according to this invention. Importantly, the wing 40 is preferably also elongate in form with a length about twice (or more) that of a width thereof.
The wing 40 is adapted to rotate relative to the housing 20 (along arrow A of
Electrical leads 50 or outlet tubes 60 preferably extend from one of the ends 24 of the housing 20 or some other portion of the housing 20. To keep the wing 40 in its deployed position, it is conceivable that the bottom 25 of the housing 20 and the top of the wing 40 could be configured so that they include appropriate detent structures so that the wing 40 snaps into a final deployed position once rotated relative to the housing 20. Alternatively, holes can be formed in the housing 20 and the wing 40 which can receive sutures to tie the wing 40 in its open position relative to the housing 20.
Should the pacemaker 10 or other medical device require removal, the wing 40 can merely be rotated back to its implantation position by overcoming forces associated with the detents in the wing 40 and the housing 20, or by severing sutures to allow the wing 40 to freely rotate back to its implantation position with a long axis of the wing 40 aligned with a long axis of the housing 20. Whenever such implantation or removal occurs, a relatively small incision is required to pass through the skin and yet a stable medical device is still provided.
While the wing 40 is shown as a preferred form of stabilizing element, other forms of stabilizing elements could also be utilized including spring loaded stabilizing elements which automatically deploy after passing through the skin or reaching the incision site. Also, the wing 40 could be in the form of a pair of wings (
The wing 40 can be rotated after the medical device has reached the implantation site or immediately after passing through an incision in the skin. Such rotation can occur manually, such as through use of an appropriate probe or manipulation with the fingers. Most preferably, such rotation is achieved through use of a spring that biases the wing 40 to its deployed position extending laterally from the housing 20 long axis. Such a spring can be a torsion spring adjacent the axle 30 and contained within a recess in the wing 40 adjacent the axle 30, and/or a recess in the bottom of the housing 20 adjacent the axle 30. The spring could be formed of a biocompatible metal such as titanium (or alloys thereof) or made of a biocompatible plastic or other other non-metal material. The spring could also be a linear compression spring or other linear force applying spring located further from the axle 30 and interposed between the wing 40 and the housing 20. With such a spring, the wing 40 is both advanced to the deployed configuration and held in the deployed configuration after rotation. Further support in the deployed position can be provided by detents or suturing also.
With particular reference to
Uniquely, the housing 120 includes a cavity 130 therein. Preferably, this cavity 130 is closer to the bottom 125 than to the top 128 and has a planar form within a plane perpendicular to a vertical axis and aligned with both a long axis and a lateral axis for the housing 120. A long axis is defined as an axis extending from the front end 122 to the rear end 124 and the lateral axis is defined as an axis extending between the sides 126. The cavity 130 includes a roof 132 which is planar in form and spaced a constant distance away from a floor 134. An abutment wall 135 defines a wall extending from the roof 132 to the floor 134 on a side of the cavity 130 adjacent the front end 122 of the housing 120. The cavity 130 also includes side openings 136 extending out sides 126 of the housing 120 and a rear opening 138 extending out of the rear end 124 of the housing 120.
A loop 140 is provided as a preferred form of stabilizing element which can reside within the cavity 130 and extend laterally out of at least one of the side openings 136 and preferably both of the side openings 136 to stabilize the housing 120 after implantation. The loop 140 in this preferred form shown includes four legs 142 joined together by a front joint 146, side joints 144 and a rear joint 148. The front joint 146 is located adjacent the abutment wall 135. The rear joint 148 is adjacent the rear opening 134. The side joints 144 are adjacent the side openings 136. The loop 140 is sized so that the side joints 144 extend out of the side openings 136 and enhance an effective width and footprint of the housing 120 of the first alternative pacemaker 110. An interface port 150 extends from the housing 120 which can be in the form of electric leads or a fluid tube depending on the type of medical device provided, such as the pacemaker 110.
While a continuous loop 140 is shown, other stabilizing elements could be provided of similar form but not a complete loop. For instance, any one of the joints might be omitted so that adjacent legs 142 end at free ends, and such a modified loop would still function somewhat effectively.
The loop 140 can be deployed a variety of different ways relative to the cavity 130 of the housing 120. In one embodiment the loop 140 can be provided within the cavity 130 during implantation. The loop 140 can be sufficiently flexible that as the pacemaker 110 is advanced through an incision, the side joints 144 are merely flexed towards each other as they pass through the incision. The loop 140 would be formed of a resilient material so that the side joints 144 would spring to a natural original position (along arrow C of
Alternatively, the loop 140 could be formed of a plastically deformable material, such as a surgical stainless steel with thin cross-section legs 142 and initially reside within the cavity 130, but passing out of the rear opening 138 somewhat and not passing out of the side openings 136. After reaching the implantation site, the rear joint 148 would be advanced toward the front joint 146 and the loop 140 would be caused to bend so that the side joints 144 would bend away from each other and out of the side openings 136.
As another alternative, the loop 140 could be formed as bendable material but be advanced later, such as through a cannula (along arrow B of
With particular reference to
Uniquely, a pair of wings 240, 250 are pivotably attached to the axle 230 of the housing 220. In particular, these wings 240, 250 include a top wing 240 and a bottom wing 250. The top wing 240 is closer to the bottom 225 of the housing 220 and includes a hub 242 adjacent the axle 230 with a hole therein that allows the top wing 240 to be mounted to the axle 230. Arms 244 extend in opposite directions away from the hub 242 to tips 246. A recess 245 is provided adjacent the hub 242 into which the bottom wing 250 can partially reside so that the top wing 240 and bottom wing 250 can remain within a substantially common plane with each other both before and after rotation thereof. Preferably, at least one of the tips 246 of the top wing 240 includes a bevel 248 thereon on a portion of the top wing 240 which extends most rearwardly on the top wing 240.
The bottom wing 250 includes a hub 252 adapted to be mounted on the axle 230 and adapted to reside within the recess 245 in the top wing 240. The bottom wing 250 is most distant from the bottom 225 of the housing 220. Arms 254 extend in opposite directions away from the hub 252 to tips 256. Preferably, at least one of the tips 256 includes a bevel 258 thereon on a portion of one of the arms 254 which extends most rearwardly. This bevel 258 preferably at least partially faces the bevel 248 of the top wing 240.
The wings 240, 250 are each adapted to rotate relative to each other and relative to the housing 220 (arrows E and F). Initially, the wings 240, 250 reside substantially within a perimeter 222 of the housing 220. After rotation (along arrows E and F) the wings 240, 250 extend outside this perimeter 222 of the housing 220 to enhance the stability of the pacemaker 210 or other alternative medical device.
Preferably, a cannula 260 can be placed adjacent the pacemaker 210 and a spreader rod 270 can be advanced through the cannula 260 and pressed between the bottom wing 250 and top wing 240. The spreader rod 270 can press against the bevel 248 and bevel 258 to cause simultaneous rotation of the top wing 240 and bottom wing 250 in opposite directions relative to each other and relative to the housing 220. Such rotation preferably occurs for at least 45° so that the wings 240, 250 form an “X.” A rather desirable stabilized form would involve rotation of 60° so that the wings 240, 250 and ends 224 of the housing 220 would define six peripheral ends for the overall final implanted pacemaker 210 or other implanted medical device. Advancement of the spreader rod 270 along arrow D (
The medical device 210 can have the pair of wings advanced and held in the deployed position by action of a spring, similar to that described in conjunction with the embodiment of
This disclosure is provided to reveal a preferred embodiment of the invention and a best mode for practicing the invention. Having thus described the invention in this way, it should be apparent that various different modifications can be made to the preferred embodiment without departing from the scope and spirit of this invention disclosure. When structures are identified as a means to perform a function, the identification is intended to include all structures which can perform the function specified. When structures of this invention are identified as being coupled together, such language should be interpreted broadly to include the structures being coupled directly together or coupled together through intervening structures. Such coupling could be permanent or temporary and either in a rigid fashion or in a fashion which allows pivoting, sliding or other relative motion while still providing some form of attachment, unless specifically restricted.
Claims
1: A method for minimally invasive implantation of a subcutaneous medical device, the method including the steps of:
- configuring the medical device to be at least partially contained within a housing having an elongate form with a long axis between ends greater than a lateral axis non-parallel with the long axis;
- making an incision large enough to pass the housing through the incision along the long axis;
- passing the housing through the incision to a subcutaneous implantation site; and
- manipulating a stabilizing element coupled to the housing to enhance a lateral width of the housing, such that the stabilizing element resists rotation of the housing about the long axis.
2: The method of claim 1 including the further steps of:
- configuring the stabilizing element as a rotating wing pivotably attached to the housing; and
- said manipulating step including the step of rotating the stabilizing element from a first position aligned with the long axis to a second position extending laterally a distance greater than a width of the housing.
3: The method of claim 2 including the further step of configuring the rotating wing to have a length greater than a width of the housing so that ends of the rotating wing extend laterally from sides of the housing upon rotation of the rotating wing at least 45° from initially aligned with the long axis.
4: The method of claim 2 wherein said manipulating step includes the step of manipulating a pair of the stabilizing elements in the form of a pair of rotating wings in opposite directions relative to the housing.
5: The method of claim 4 including the further step of advancing a spreader rod toward the housing and between the two wings to cause rotation of the two wings in opposite directions away from each other and relative to the housing.
6: The method of claim 1 including the further steps of:
- configuring the housing to include a cavity therein with a rear opening and at least one side opening; and
- configuring the stabilizing element to be in the form of an expandable element which can pass through the rear opening and expand laterally out of said at least one side opening.
7: The method of claim 6 including the further steps of:
- configuring the cavity to include at least two side openings opposite each other; and
- extending said expandable element laterally out of both side openings simultaneously.
8: The method of claim 7 including the further steps of configuring the expandable element as a loop.
9: The method of claim 8 including the further steps of configuring the expandable element to include four legs joined together by four joints including two side joints which extend away from each other and out of the side openings when a rear joint of the loop is moved toward a front joint of the loop.
10: A method for reconfiguring a subcutaneous medical device, the method including the steps of:
- identifying a subcutaneous medical device at least partially contained within a housing and having an elongate form between a front end spaced from a rear end by a longest dimension and extending along a long axis, the housing having lateral sides spaced from each other by a lateral width that is less than the longest dimension; and
- manipulating a stabilizing element to be coupled to the housing and enhance the lateral width of the housing, such that the stabilizing element resists rotation of the housing about the long axis after the stabilizing element is coupled to the housing.
11: The method of claim 10 wherein said manipulating step includes the step of deforming the stabilizing element from a first configuration that is narrower than the width of the housing between the lateral sides, into a second configuration that is wider than the width of the housing between the lateral sides.
12: The method of claim 11 including the further step of extending the stabilizing element laterally in opposite directions past each of the lateral sides of the housing.
13: The method of claim 12 including the further steps of identifying a cavity in the housing with lateral side openings and a rear opening, and inserting the stabilizing element into the rear opening and causing the stabilizing element to extend laterally out of the side openings in the cavity of the housing.
14: The method of claim 13 including the step of configuring the stabilizing element to maintain plastic deformation after extending out of the side openings in the cavity.
15: The method of claim 14 including the further step of identifying the stabilizing element having a resilient character and with a bias toward a width sufficient to extend out of the openings in the cavity of the housing unless forces are applied to the stabilizing element to elastically compress the stabilizing element to a width less than the width of the housing.
16: The method of claim 10 including the further step of coupling the stabilizing element to the housing with the stabilizing element having a longest dimension greater than the lateral width of the housing, with the stabilizing element coupled in an orientation which enhances an overall lateral width of the housing when the stabilizing element is coupled thereto.
17: A method for stabilizing a subcutaneous medical device, the method including the steps of:
- identifying a subcutaneous medical device at least partially contained within a housing and having an elongate form between a front end spaced from a rear end by a longest dimension and extending along a long axis, the housing having lateral sides spaced from each other by a lateral width less than the longest dimension; and
- manipulating a stabilizing element coupled to the housing, to move the stabilizing element from a first orientation with the stabilizing element inboard of the lateral sides of the housing to a second orientation with at least one tip of the stabilizing element extending past at least one lateral side of the housing, such that the stabilizing element resists rotation of the housing about the long axis.
18: The method of claim 17 wherein said manipulating step includes pivoting an elongate wing that defines a portion of the stabilizing element about an axle extending perpendicular to the long axis, the wing including at least one tip spaced from the axle sufficient to cause the tip to extend past at least one lateral side of the housing when the pivoting wing is pivoted away from an orientation parallel with the housing long axis.
19: The method of claim 18 including the further step of configuring the stabilizing element to include a pair of wings each attached about a common axle perpendicular to the long axis of the housing, the wings each pivoting from a first position corresponding with a first orientation and substantially within an outline of the housing and a second position corresponding with the second orientation with tips of the wings extending from the lateral sides of the housing, such that the stabilizing elements resist rotation of the housing about the long axis.
20: The method of claim 19 including the further step of providing a push rod which can push between adjacent ends of the two wings to spread the adjacent ends of the two wings away from each other and cause the two wings to rotate from the first position to the second position.
Type: Application
Filed: Jun 25, 2012
Publication Date: Oct 18, 2012
Inventor: Bradley J. Glenn (Danville, CA)
Application Number: 13/532,303
International Classification: A61M 25/04 (20060101);