CROSS-REFERENCE TO RELATED APPLICATIONS
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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 INVENTION
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The 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.
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OF THE INVENTION
A 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.
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OF THE INVENTION
With 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 INVENTION
Accordingly, 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.
BRIEF DESCRIPTION OF THE DRAWINGS
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FIG. 1 is a bottom plan view of an implantable medical device shown before rotation of a wing thereof to stabilize the medical device.
FIG. 2 is a bottom plan view similar to that which is shown in FIG. 1 but after rotation of the stabilizing element in the form of a wing to stabilize the medical device.
FIG. 3 is a bottom plan view of an implantable medical device having a cavity and a loop which can pass into the cavity and expand within the cavity to stabilize the housing.
FIG. 4 is an end elevation view of that which is shown in FIG. 3.
FIG. 5 is a side elevation view of that which is shown in FIG. 3.
FIG. 6 is a bottom plan view of that which is shown in FIG. 3 but with a stabilizing element in the form of a loop delivered through a cannula to utilize the stabilizing element in the form of a loop that is biased toward a deployed position but retrained in a narrow configuration before insertion into the cavity of the housing.
FIG. 7 is a bottom plan view similar to that which is shown in FIG. 6 but after positioning of the stabilizing element from the cannula into the cavity.
FIG. 8 is a bottom plan view of an alternative embodiment medical device and associated cannula with the medical device featuring a pair of rotating wings pivotably attached thereto and a spreader rod for use in spreading the pair of wings opposite each other for conversion of the medical device from an implantation form to a stabilized form.
FIG. 9 is a bottom plan view similar to that which is shown in FIG. 8 but after advancing the spreader rod and rotating the wings to the final stabilized configuration.