Abstract:
In general all embodiments relate to implantable medical devices including at least one injectable device and at least one anchor for fixation of the injectable device to body tissue. The anchor of the implantable medical device fulfills the requirement for secure anchoring of the injectable device to body tissue. The medical device includes at least one contrast agent reservoir with an outlet, wherein the reservoir is filled with a contrast agent, which may be released through the outlet into body tissue or cavities. The contrast agent is able to be visible with known imaging methods comprising X-ray or Mill imaging or other well-known techniques to determine if a secure anchoring of the medical has been achieved.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This patent application claims the benefit of co-pending U.S. Provisional Patent Application No. 62/249,958, filed on Nov. 3, 2015, which is hereby incorporated by reference in its entirety. 
     
    
     TECHNICAL FIELD OF THE INVENTION 
       [0002]    Embodiments disclosed herein relate to apparatuses and methods for anchoring implantable medical devices to body tissue and, in particular, to apparatuses and methods for ascertaining whether an implantable medical device is properly seated within and/or attached to body tissue. 
       BACKGROUND OF THE INVENTION 
       [0003]    Implantable medical devices can be used to monitor, stimulate and/or regulate organs and physiological functions of a living being (e.g. animal, human, etc.). Generally, the medical device is secured by connecting it to body tissue, with the body tissue being the tissue of the body part the medical device is monitoring (sensing), stimulating (pacing) and/or regulating. For example, a pacemaker may be attached to a portion of a heart to obtain signals from, and/or generate signals for functions of, the heart. As another example, a venous access port may be attached to a vein to provide medications to the body via the vein. Attaching an implantable medical device to a body tissue may be referred to as anchoring the device. As a further example, an implantable neurostimulator may be placed in close proximity to a nerve fibre, nerve bundle, spinal cord or other tissue comprising nerve cells to obtain signals from, and/or generate signals to influence the transmitting of signals. Further examples relate to implantable electrode leads like, for example, cardiac stimulation leads, which are associated with, for example, pacemakers. 
         [0004]    One of the major problems during implantation of an implantable medical device concerns anchoring the device to body tissue in order to ensure patient safety and good sensing/pacing. Problems exist if the implantable medical device is not anchored well (i.e, loosely anchored) to the body tissue. During implantation, perforations of tissue, especially heart tissue, can occur. Clinical trials have shown that one of the most occurred problems concerns the perforation of tissue, for example, cardiac tissue, by over twisting the medical device or applying high pressure during implantation at the implantation site. If a perforation happens during surgery, immediate emergency care must be provided. Other problems relate to insufficient anchoring (i.e., not properly seated within and/or attached to the tissue), which can lead to problems during sensing and/or stimulation. In one instance, such situations can occur if the device is not implanted orthogonally. 
         [0005]    Depending on the particular implanted device, proper anchoring may take a number of forms. For example, some medical devices may perform optimally when abutting the tissue, but malfunction when not abutting the tissue. Other medical devices may perform optimally when seated within the tissue at a certain depth, but malfunction when not seated within the tissue at a certain depth. Still, other medical devices may perform optimally when attached at a particular distance from the tissue, but malfunction when not attached at a distance from the tissue. These situations can develop due to improper anchoring of the medical device during implantation or shifting of the medical device after implantation. 
         [0006]    Further problems can arise if the tissue to which the medical device is attached becomes damaged. Damage to tissue may occur by applying too much pressure while attaching the device to the tissue, resulting in a tear in and/or perforation of the tissue. Damage may also occur after the device is attached if the device is caused to shift, resulting in a tear and/or perforation of the tissue. 
         [0007]    The present invention is directed toward overcoming one or more of the above-mentioned problems. 
       SUMMARY OF THE INVENTION 
       [0008]    Embodiments of the disclosure relate to anchors of injectable devices, for example, implantable leadless pacemakers. Additionally, the disclosure relates to a method of controlling the optimal implantation of an implantable device without the perforation of body tissue (e.g., heart tissue). The injectable device includes an anchor which is contrast agent enhanced, such that contrast agent may be released from the anchor, either on-demand or self-released after a defined period of time. 
         [0009]    The inventive apparatus, as described herein, includes an anchor that may be attachable to an implantable medical device and can be further structured to attach the implantable medical device to body tissue. A proximal portion of the anchor can be configured to temporarily or permanently attach to the implantable medical device, and a distal portion of the anchor can be configured to temporarily or permanently attach to body tissue. The apparatus may further include a reservoir having a contrast agent fluid contained therein. The apparatus may further include a discharge channel having a pathway formed therein to facilitate a flow of fluid (e.g., a contrast agent), where the pathway may have an inlet end in fluid connection with a reservoir and an outlet end configured to dispense fluid taken from the reservoir. In a specific embodiment, the discharge channel comprises the reservoir. The pathway of the discharge channel may be routed from the reservoir to the distal portion of the anchor so that the outlet end of the discharge channel can be positioned at or near the distal portion of the anchor. The discharge channel may be formed within the anchor, or may be a separate member attached to the anchor. 
         [0010]    During and/or after attaching the implantable medical device to body tissue via the anchor, fluid can be taken from the reservoir and forced to flow through the discharge channel and be dispensed to a volume of space outside of the outlet end. The anchor can be structured such that if the implantable medical device is properly seated within the body tissue and/or attached to the body tissue, the outlet end can be positioned within the body tissue, and fluid can be dispensed into, or at least substantially into, the body tissue. However, if the implantable medical device is not properly seated within the body tissue and/or attached to the body tissue, the outlet end can be positioned outside of the body tissue, and fluid thus dispensed outside the body tissue. Such a situation can occur if, for example, the implantable medical device is seated too far into the body tissue and the distal portion of the anchor perforates the body tissue. In this instance, fluid from the discharge channel would flow outside of the body tissue. As another example, if during implantation, manipulation of the anchor tears the body tissue so as to degrade the structural integrity of the tissue surface at the attachment point, fluid may not be contained by the body tissue, and thus the fluid may be disbursed substantially outside of the body tissue. 
         [0011]    During and/or after attaching the implantable medical device to the body tissue via the anchor, imaging of the implantation site via X-ray, Magnetic Resonance Imaging (“MRI”), ultrasound, or other imaging techniques may be performed. The fluid can then be dispensed as the imaging is conducted or before the imaging is conducted. The fluid being dispensed can be a contrast fluid that appears very distinctly in the image due to reactions with the energies emitted by the imaging apparatus (e.g., excitations with x-rays, resonant vibrations with magnetic signals, echogenicity with sound waves, etc.). The observance or lack of observance of a distinct appearance that may be caused by the contrast fluid can be used as a proxy for whether the implantable medical device is properly seated within and/or attached to the body tissue. The fluid may be a liquid, a solvable powder or a solvable solid object, or the like. 
         [0012]    For instance, if the implantable medical device is properly seated/attached, the contrast fluid may not be able to be dispensed at all, or dispense very slowly, because the tissue is obstructing the flow of fluid from the outlet end, and/or the body tissue may obscure the contrast fluid because it is being substantially contained within the body tissue. Thus, observing no or very little contrast effect can indicate that the implantable medical device may be properly seated/attached. If the implantable medical device is not properly seated/attached, the contrast fluid may dispense quickly and be dispensed outside, or substantially outside, of the tissue-body and into close by cavities. Thus, observing a contrast effect that is more like a scattering and/or diffusing pattern caused by disbursement of the fluid and/or an observance of an image contrast appearing for an unexpected body tissue caused by saturation of the fluid into a neighboring body tissue can indicate that the implantable medical device may not be properly seated/attached. 
         [0013]    Use of the apparatus and the disclosed method can not only determine if the implantable medical apparatus is properly seated/attached, but it can also determine if damage to the tissue-body has occurred. Damage to the body-tissue can require urgent care. Thus, the apparatus and method of use can enable medical professionals to ascertain, in real time, whether damage is occurring (e.g., a perforation) and/or has occurred so that immediate emergency care can be taken. Damage, such as tissue perforation, may occur due to over-twisting the anchor or applying too much pressure to the anchor when piercing the tissue-body to effectuate the attachment thereto. Damage and/or improper seating/attachment can also be caused by the implantable medical device not being implanted orthogonally. 
         [0014]    The inventive apparatus and method can provide an easy-to-perform control mechanism for recognizing fixation problems during and/or after attaching an implantable medical device to tissue via the anchor. Furthermore, optimal implantation can be ensured without harm to the patient. 
         [0015]    While these potential advantages are made possible by technical solutions offered herein, they are not required to be achieved. The presently disclosed apparatus and method can be implemented to achieve technical advantages, whether or not these potential advantages, individually or in combination, are sought or achieved. 
         [0016]    It is an object of the present disclosure to provide an easy-to-perform control mechanism for recognizing fixation problems in implantable medical devices. 
         [0017]    It is a further object of the present disclosure to ensure optimal implantation of an implantable medical device without harm to the patient. 
         [0018]    In one embodiment of the inventive apparatus, an anchoring control system comprises at least one anchor having a proximal portion affixed to an implantable medical device and a distal portion capable of being affixed to body tissue, a reservoir having a contrast agent fluid contained therein, and at least one discharge channel associated with the at least one anchor, the at least one discharge channel being in fluid communication with the reservoir and having an outlet at the distal portion of the at least one anchor, wherein contrast agent fluid is provided through the discharge channel and output at the outlet to determine whether the implantable medical device is properly affixed to the body tissue. 
         [0019]    In this embodiment, the reservoir may be disposed within the implantable medical device. Additionally, or alternatively, the reservoir may be attached to the implantable medical device, either permanently or temporarily. 
         [0020]    In one variant of the above mentioned anchoring control system, the reservoir may comprise a compressible, fluid absorbent member attached to the implantable medical device, wherein compression of the member forces contrast agent fluid through the discharge channel and outlet. The compressible, fluid absorbent member of this variant may comprise, for example, a sponge. 
         [0021]    In an alternative embodiment of the inventive apparatus, an anchoring control system comprises at least one anchor having a proximal portion affixed to an implantable medical device and a distal portion capable of being affixed to body tissue, and at least one discharge channel associated with the at least one anchor, the at least one discharge channel having an outlet at the distal portion of the at least one anchor, a pathway and a reservoir, wherein the pathway is in fluid communication with the reservoir and the outlet, wherein contrast agent fluid is provided through the discharge channel and output at the outlet to determine whether the implantable medical device is properly affixed to the body tissue. 
         [0022]    In one implementation of the mentioned embodiments of the inventive apparatus, the at least one anchor may be hollow, and the at least one discharge channel is provided within the at least one anchor. 
         [0023]    In an alternative implementation of the mentioned embodiments of the inventive apparatus, the at least one discharge channel may be provided within a hollow wire provided adjacent to the at least one anchor. In one embodiment of this implementation, the hollow wire may be made of a biodegradable material. 
         [0024]    In one embodiment, the anchor control of the mentioned embodiments of the inventive apparatus may comprise a pump which is controllable to force the contrast agent fluid through the discharge channel and the outlet. 
         [0025]    A further subject matter of this disclosure is an implantable medical device comprising one of the above mentioned inventive apparatuses. 
         [0026]    In one embodiment of the implantable medical device, the at least one anchor is hollow, and wherein the at least one discharge channel is provided within the at least one anchor. 
         [0027]    In one embodiment of the implantable medical device, the at least one discharge channel is provided within a hollow wire provided adjacent to the at least one anchor. In one implementation of this embodiment, the hollow wire is made of a biodegradable material. 
         [0028]    In this embodiment, the reservoir may be disposed within the implantable medical device. Additionally, or alternatively, the reservoir may be attached to the implantable medical device, either permanently or temporarily. 
         [0029]    In one variant, the above mentioned implantable device further comprises a biodegradable cap provided on the distal portion of the anchor and covering the outlet of the discharge channel, the biodegradable cap configured to dissolve after a predetermined period of time to allow contrast agent fluid to discharge from the outlet. 
         [0030]    The contrast agent fluid, which is used and provided within the reservoir, is visible in and around the body tissue using an imaging device. Further, an amount of contrast agent fluid released that is visible may provide an indication of whether or not the implantable device is properly affixed to the body tissue. 
         [0031]    In one embodiment of the implantable medical device, the reservoir is disposed within the implantable medical device. 
         [0032]    In one variant of the implantable medical device, the reservoir may comprise a compressible, fluid absorbent member attached to the implantable medical device, wherein compression of the member forces contrast agent fluid through the discharge channel and outlet. The compressible, fluid absorbent member of this variant may comprise a sponge. 
         [0033]    A further aspect of the present invention comprises a method for controlling attachment of an implantable medical device to body tissue, the method comprising the following steps: 
         [0034]    anchoring an implantable medical device to body tissue at an implantation site, the implantable medical device comprising a housing, at least one anchor having a proximal portion affixed to the housing and a distal portion capable of being affixed to body tissue, and at least one discharge channel associated with the at least one anchor, the at least one discharge channel in fluid communication with a reservoir having a contrast agent fluid contained therein, and the at least one discharge channel having an outlet at the distal portion of the at least one anchor; 
         [0035]    actuating a flow of the contrast agent fluid from the reservoir and through the discharge channel and out the outlet, wherein the contrast agent fluid is discharged into and around the body fluid; 
         [0036]    viewing the implantation site using an imaging technique to identify at least one of a pattern or a flow of the contrast agent fluid; and 
         [0037]    determining whether the implantable medical device is properly affixed to the body tissue based on the at least one pattern or flow of the contrast agent fluid. 
         [0038]    Further embodiments, features, aspects, objects, advantages, and possible applications of the present invention could be learned from the following description, in combination with the Figures, and the appended claims. 
     
    
     
       DESCRIPTION OF THE DRAWINGS 
         [0039]    The above and other objects, aspects, features, advantages and possible applications of the present invention will be more apparent from the following more particular description thereof, presented in conjunction with the following drawings, in which: 
           [0040]      FIG. 1  is a perspective view of an exemplary apparatus positioned next to a heart (i.e., tissue body) to which the apparatus may be attached, with the anchor separated from the implantable medical device. 
           [0041]      FIG. 2  is a side view of an exemplary apparatus in accordance with the present invention. 
           [0042]      FIG. 3A  shows an exemplary apparatus in accordance with the present invention that illustrates an implantable medical device properly seated/attached to body tissue. 
           [0043]      FIG. 3B  shows an exemplary apparatus that illustrates an implantable medical device improperly seated/attached to body tissue and perforating the body tissue. 
           [0044]      FIG. 4A  shows a cross-section view taken along line A-A in  FIG. 2  illustrating an exemplary anchor having a lumen formed within a central portion of the anchor, which may be used as a discharge channel for a contrast agent routed therein. 
           [0045]      FIG. 4B  shows cross-sectional view taken along line A-A in  FIG. 2  illustrating an exemplary solid anchor and an exemplary discharge channel being formed in a wire routed alongside an exemplary anchor. 
           [0046]      FIG. 5  shows an exemplary apparatus in the form of a fluid connector which connects the outlets with an implantation tool like an implantation catheter. 
           [0047]      FIG. 6  shows an exemplary apparatus with a cross-sectional view of an exemplary absorbent member as part of the apparatus. 
           [0048]      FIG. 7  is a side view of another exemplary apparatus in accordance with the present invention. 
           [0049]      FIG. 8  shows a cross-section view taken along line B-B in  FIG. 7  illustrating an exemplary anchor with rectangular cross-section having a rectangular lumen formed within a central portion of the anchor, which may be used as a discharge channel for a contrast agent routed therein. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0050]    The following description of embodiments presently contemplated for carrying out the present invention. This description is not to be taken in a limiting sense, but is made merely for the purpose of describing the general principles and features of the present invention. The scope of the present invention should be determined with reference to the claims. 
         [0051]    Referring to  FIGS. 1-4 , the apparatus  10  can include an anchor  12  configured to temporarily or permanently affix to body tissue and discharge a fluid  14  into and/or around the tissue. The anchor  12  may be configured to attach to various types of tissue, which can be any one or combination of epithelium tissue, muscle tissue, connective tissue, and/or nervous tissue, which may include cardiac tissue. In some embodiments, the anchor  12  can be further configured to temporarily or permanently affix to an implantable medical device  16 . In at least one embodiment, the anchor  12  can be flexibly attached to the implantable medical device  16 . 
         [0052]    The implantable medical device  16  may include a casing/housing having components  18  housed therein and/or components  18  attached thereto. The components  18  of the implantable medical device may include electrical circuitry, pumps, transducers, transceivers, sensors, motors, actuators, etc. to diagnose, prevent, and/or treat physiological and other conditions of the living being and also to force the fluid  14  through the anchor, as described herein. The implantable medical device  16  may achieve this by monitoring and/or regulating organs or other components placed within or onto the being. For example, the implantable medical device  16  may be an implantable leadless pacemaker used to monitor and regulate the heart. The implantable medical device can also include other injectable devices, such as a venous access port or a neurostimulator (Vagus Nerve Stimulation, Spinal Cord Stimulation, Deep Brain Stimulation, for example), which also may be injectable, for example. 
         [0053]    The fluid  14  (which may be a liquid, a solvable powder or a solvable solid object, or the like) is provided in a reservoir  20 . As shown in  FIGS. 1-2 , the reservoir  20  may be provided within the implantable medical device  16 . However, the reservoir  20  may also be attached to the implantable medical device  16  or otherwise provided outside of the device  16  without departing from the spirit and scope of the present invention. The only requirement is that the reservoir be in fluid communication with a discharge channel  28 . 
         [0054]    The implantable medical device  16  may be attached to the anchor  12  at a proximal portion of the anchor  12 , while a distal portion of the anchor  12  can be used to attach the apparatus  10 , along with the implantable medical device  16 , to the body tissue. The anchor  12  is preferably contrast fluid enhanced (i.e., provided with a means to dispense contrast fluid) so as to dispense contrast fluid  14  while the apparatus  10  and the implantable medical device  16  are attached to the body tissue. The dispensing of contrast fluid, or agent,  14  may be controlled via a controller included within the components  18 , such that the contrast fluid  14  can be dispensed automatically or on demand by a user. 
         [0055]    The anchor  12  can include a first end  22  (distal end or distal portion), a shank  24 , and a second end  26  (proximal end or proximal portion). The shank  24  is generally the body of the anchor that lies between the first end  22  and the second end  26 . The anchor  12  may be a semi-rigid or rigid member fabricated from metal, plastic, carbon composite, fiberglass, ceramic, etc. It is contemplated for the anchor  12  to be configured to pierce body tissue and be retained therein, thus securing the medical device  16  thereto in a proper seating arrangement. This can be achieved by providing the anchor  12  with various shapes, lengths, widths, and sizes. For instance, if the implantable medical device  16  is intended to rest against the body tissue, the anchor  12  may be configured to enable attachment so as to facilitate the implantable medical device  16  resting against the body tissue with little or no volume of space existing between an interface of the implantable medical device  16  and a surface of the body tissue. As another example, if the implantable medical device  16  is intended to be attached to the body tissue but have a volume of space between a surface of the implantable medical device  16  and the body tissue, then the anchor  12  may be configured to enable attachment of the implantable medical device  16  in such a way. 
         [0056]      FIGS. 3A and 3B  show an exemplary implantable medical device  16  being optimally implanted and improperly implanted where the anchor perforates the tissue-body, respectively.  FIG. 3A  shows proper attachment with the implantable medical device  16  anchored to the body tissue with the anchor  12  within the body tissue.  FIG. 3B  shows improper attachment with the implantable medical device  16  anchored to the body tissue with the anchor  12  perforating the body tissue. As will be explained in more detail hereafter, a discharge channel  28  is provided that is in or associated with the anchor  12  to facilitate dispensing of fluid  14  (contrast agent) therefrom. In  FIG. 3A , with the anchor  12  within the body tissue, the fluid  14  with diffuse into the body tissue. In  FIG. 3B , with the anchor  12  perforating the body tissue, the fluid will diffuse into neighboring chambers or pericardial space. An imaging device (not shown) can be used to view the fluid  14  and determine if the implantable device  16  is properly attached or seated. 
         [0057]    During implantation, the fluid  14  is kept in or at the medical device  16 . After implantation, an active or passive process can start the release of fluid  14  from the device  16 . For example, in  FIG. 3A  with the anchor  12  securely within the body tissue, the fluid  14  will be kept in the device  16  and/or elute slowly into the body tissue regions. In the case of a perforation, as shown in  FIG. 3B , or another not well performed anchoring, the fluid  14  will elute relatively fast into close by cavities. Both of these conditions can be identified utilizing imaging apparatus, and the amount of fluid  14  visible can be used to determine if the device  16  is well anchored or not. The more fluid  14  that is visible, the more likely it is that the device is not well anchored and/or a perforation has occurred. 
         [0058]    The first end  22  may be used to spearhead the incision of the anchor  12  into the body tissue, so the first end  22  may be structured as a pointed end to facilitate piercing tissue. The first end  22  may be referred to as the distal portion because in some embodiments the first end  22  is the portion of the apparatus  10  that is most distal to a practitioner when implanting an implantable medical device  16  with the apparatus  10 . 
         [0059]    The shank  24  may be a rigid or semi-rigid member structured to pierce tissue and affix itself thereto or therein. This may be by grappling the tissue, barbing the tissue, hooking the tissue, etc. In one embodiment, the shank  24  can include a coiled ridged member that is capable of being inserted into tissue and retained therein by a helicoid, helicoidal, or helical shape of the shank  24 . 
         [0060]    In another embodiment, the shank  24  is a semi-rigid member with a rectangular cross-section and can include a backward bend  25 , which allows the anchor  12  to move backwards after incision of the tissue after release of a delivery device. An example is shown in  FIG. 7 , which discloses the distal end of an implantable medical device  16 . At the distal end of the implantable medical device  16 , at least two anchors  12  are fixedly attached. Each of the at least two anchors  12  comprise a first end  22 , a shank  24  (which has a backward bent (portion)  25 ), and a second end  26 , at which the at least two anchors  12  are fixedly attached to the medical device  16 . Each of the at least two anchors  12  comprise a channel  28 , which is filled with contrast agent fluid. In other words, the hollow space within the at least one anchor  12  comprises the reservoir  20  and is filed with one or more volatile substances (contrast agent fluid  14 ). These substances can be released directly through the outlet  36  and into the body tissue or cavity. 
         [0061]    The shank  24  (and hence the anchor  12 ) may have a circular cross-section (see  FIGS. 4A and 4B ), but other cross-sections, like a flat wire with a rectangular cross-section (see  FIG. 8 ), are contemplated. The shape, width, length, and pitch of the shank  24  may be selected based upon the desired application of the implantable medical device  16 . In some embodiments, the shank  24  may be structured as a hook, a barb, a claw, a clamp, a screw, a straight member with at least one angled protrusion, etc. Once skilled in the art will appreciate, with the benefit of the present disclosure, that other of shapes, widths, lengths, and pitches may be utilized. For example, the anchor  12  may also take the form of a hook, clamp or claw. 
         [0062]    The second end  26  may be structured as a securement end to temporarily or permanently attach to an ancillary object (e.g., an implantable medical device  16 ). The second end  26  may be referred to as the proximal portion because in some embodiments the second end  26  is the portion of the apparatus  10  that is most proximal to a practitioner when implanting an implantable medical device  16 . 
         [0063]    In alternative embodiments, the anchor  12  can be integral to the implantable medical device  16 . For example, the second end  26  can be molded from the casing/housing or other structure of the implantable medical device  16 , and thus be integral to the implantable medical device  16 . 
         [0064]    The discharge channel  28  is provided either within or adjacent the anchor  12  and is configured to facilitate transfer of contrast agent fluid  14  there through. The discharge channel  28  may be formed within the anchor  12  (i.e., the anchor  12  is hollow), or formed in a separate member attached to the anchor  12 . The discharge channel  28  has an outlet  36  at the distal end  22  of the anchor  12 . As show in  FIG. 4A , the anchor  12  is hollow and the discharge channel  28  is provided within the anchor  12 . As shown in  FIG. 4B , the anchor  12 ′ is solid and the discharge channel  28 ′ is provided within a wire or other member  30  attached to the anchor  12 ′. The outlet  36  of the discharge channel  28 ′ in this embodiment is also at the distal end  22  of the anchor  12 . However, depending on the particular application, the outlet  36  of the discharge channel  28 ,  28 ′ may be at any portion of the anchor  12 . 
         [0065]    The discharge channel  28  is structured to be in fluid connection with at least one reservoir  20  (see  FIGS. 1-2 ). The reservoir  20  may be a container configured to retain the fluid  14  from which the discharge channel  28 ,  28 ′ facilitates transfer of the fluid  14  therefrom. The reservoir  20  can be permanently or temporarily attached to a portion of the implantable medical device  16  or a portion of the anchor  12 . The reservoir  20  can also be situated within the implantable medical device  16 . For example, the reservoir  20  may be placed at the connector housing (header) or within the housing. Additionally, or alternately, to the outlets described above, further outlets can be provided in the header on the area which faces, in the implanted state, to the body tissue. Alternatively, the reservoir  20  can be separate from both the implantable medical device  16  and the anchor  12  and in fluid communication with the discharge channel  28 ,  28 ′. The reservoir  20  can also be configured to remain outside of the body while the implantable medical device  16  and/or anchor  12  is/are inserted into the body. It is contemplated for the reservoir  20  to be refillable. 
         [0066]    The wire  30  can be structured as a tubular or flattened member, a hollow fiber, or other type of conduit with the discharge channel  28 ′ running through it. The wire  30  can be fabricated from the same material as that of the anchor  12 . Alternatively, the wire  30  can be fabricated from a biodegradable material so as to dissolve after an amount of time has elapsed. The biodegradation may be initiated once the biodegradable material comes into contact with the fluids of the being (e.g., blood). The biodegradable material may be, but is not limited to, Mg alloys, Zn alloys, Fe alloys, degradable polymers like Poly-L-Lactide acid and the like. 
         [0067]    The wire  30  can be made to biodegrade after a certain amount of time has elapsed after the implantable medical device  16  has been implanted. For example, the apparatus  10  can be used during implantation and/or shortly thereafter to ascertain if the implantable medical device  16  has been properly seated/attached and/or if any tissue damage has occurred, but then the biodegradable wire  30  degrades after a period of time. The time frame can be chosen depending on the application of the implantable device and material used for the wire  30 . This may be done to reduce possible risks involved with having a spent wire  30  within the tissue body. There can be an inherent risk, however slight, associated with leaving foreign objects in the body, thus it may be desirable to ensure that the spent wire  30  is dissolvable via biodegradation. 
         [0068]    The discharge channel  28  may have an inlet end  34  attachable to the device  16  and in fluid communication with the reservoir  20 . In some embodiments, a plurality of discharge channels  28 ,  28 ′. For example, the discharge channel  28  can be routed within the anchor  12 , and the wire  30  with discharge channel  28 ′ also provided adjacent the anchor  12 . This can facilitate the dispensing of different types of fluid  14  by taking a different fluid  14  held in a different segmented portion of the reservoir  20 . Alternately, the anchor  12  and/or wire  30  may have multiple discharge channels  28 ,  28 ′ running there through. 
         [0069]    In a preferred embodiment, the fluid  14  is a medical contrast medium and/or a contrast agent. A contrast agent can be any fluid  14  that enhances a contrast of bodily structures or bodily liquids during imaging. For example, a contrast agent may include a fluid  14  containing a substance that is radiopaque to enhance contrast between it and other structures and/or liquids when viewing the contrast agent and the other structures and/or liquids via X-ray imaging. Other contrast agents may generate a contrast effect with respect to MRI imaging, ultrasound imaging, or another imaging technique. A contrast agent may be a fluid  14  containing iodine, barium, gadolinium, etc. Contrast agents and/or other volatile substances can be dissolved in a liquid to form the fluid  14 . The principles of the present invention are based on volatile substances like liquids or solvable powders, solvable solid objects and the like, which are visible with all known (and further developed) imaging methods, including X-ray, MRI imaging, etc. All of these substances are referred to herein as contrast agent. 
         [0070]    In some embodiments, the apparatus  10  can include a pump  40  (see  FIGS. 1-2 ) to force the fluid  14  through the discharge channel  28 ,  28 ′ and out through the outlet end  36 . The pump  40  can be located in the implantable device  16  (see  FIGS. 1-2 ) or outside of the device. The pump  40  can be configured to draw the fluid  14  from, or push the fluid  14  out of, the reservoir  20  and force it through the discharge channel  28 ,  28 ′. The pump  40  may be also located within the reservoir  20 . 
         [0071]    Additionally, or alternatively, in some embodiments, the hollow space within the wire  30  or anchor  12  comprises the reservoir  20  and is filling with one or more volatile substances (fluid  14 ). These substances can be released directly through the outlet  36  and into the body tissue or cavity. 
         [0072]    In one exemplary embodiment, the pump  40  is an internal pump, like a piezoelectric pump, placed at or near the reservoir  20 . Of course, other pumps are contemplated. The pump  40  may be controlled by the surgeon either by wire through the implantation device or wirelessly so that the contrast agent (fluid  14 ) may be applied on demand. In some embodiments when a temporary fluid connector is used (see  FIG. 5 ), the surgeon can control an external pump which pumps contrast agent fluid through the temporary fluid connector to the outlet. 
         [0073]    A temporary fluid connector is shown in  FIG. 5 . The temporary fluid connector  50  is detachable and connects, via channel  52 , the discharge channel  28 ,  28 ′ with an implantation tool like an implantable catheter. The fluid  14  can be provided from an external reservoir and, in such case, the amount of fluid  14  is not limited. 
         [0074]    In another embodiment, the outlet  36  can include a temporary cap  60  (see  FIGS. 1-2 ) that can be removed (for example, by dissolving) on demand and/or after a predetermined period of time (e.g., 5-15 minutes). The temporary cap  60  may be fabricated from any of the biodegradable materials described above, such as Mg alloys, Zn alloys, Fe alloys, degradable polymers like Poly-L-Lactide acid and the like. 
         [0075]    In a further exemplary embodiment, the reservoir  20  may be replaced with a compressible, fluid absorbent member  42  which is saturated with the fluid  14  (contrast agent) and acts as the reservoir. In one form, the compressible, fluid absorbent member  42  may be a sponge. As the member  42  is compressed and squeezed (for example, during implantation of the injectable device) a volume reduction of the member  42  occurs which forces fluid  14  into the proximal end  26  of the anchor  12  and out through the outlet  36 . Upon release of the absorbent member  42 , the absorbent member  42  can rebound back to an uncompressed state so that fluid  14  may be drawn back into the absorbent member  42  for subsequent dispensing of fluid  14 . 
         [0076]    An exemplary method of using the apparatus  10  may include use with an implantable medical device  16  (e.g., an implantable leadless pacemaker). The second end  26  of the anchor  12  can be attached to a portion of the implantable medical device  16 . An incision can be made into the living being, generating a pathway to the body tissue (e.g., a heart) and creating an implantation site. The apparatus  10 , along with the implantable medical device  16 , can be introduced into the living being through the incision so that the first end  22  of the anchor  12  is distal to the user introducing the apparatus  10 . The implantable medical device  16  can then be affixed to the body tissue by causing the first end  22  of the anchor  12  to pierce the tissue of the body tissue and manipulating (e.g., twisting) the anchor  12  to retain the implantable medical device  16  adjacent to the tissue-body, thus completing implantation. During implantation, the fluid  14  may be caused to remain in the reservoir  20 . After or during implantation, active dispensing of fluid  14  can commence by a user (or an automated feature) activating the pump  40  or other device to force or pull fluid  14  through the discharge channel  28 ,  28 ′ and out the outlet end  36 . A user may then view the implantation site using an imaging technique to identify any patterns or flows of fluid  14 . A user can determine that the implantable medical device  16  has been properly seated/attached by observing non-contrast effect due to no or little fluid  14  being visible and/or a slow contrast effect due to slow dispensing and elution of fluid  14  into tissue of the body tissue. A user can determine that the implantable medical device has not been properly seated/attached by observing a visually apparent contrast effect due to quick dispensing and elution of fluid  14  into a nearby body-cavity. If a perforation has occurred, the user can take immediate and appropriate action. 
         [0077]    It will be apparent to those skilled in the art that numerous modifications and variations of the described examples and embodiments are possible in light of the above teachings of the disclosure. The disclosed examples and embodiments are presented for purposes of illustration only. Other alternate embodiments may include some or all of the features disclosed herein. Therefore, it is the intent to cover all such modifications and alternate embodiments as may come within the true scope of this invention, which is to be given the full breadth thereof. Additionally, the disclosure of a range of values is a disclosure of every numerical value within that range, including the end points.