Abstract:
A technique for accessing a pericardial space of a heart includes attaching a grip to a pericardium with adhesive, grasping the grip, drawing the pericardium away from the heart, and perforating the pericardium. The grip may consist solely of an adhesive. In other embodiments, other structures for the grip are used, including anchors, suture loops, and gripping tubes.

Description:
TECHNICAL FIELD  
       [0001]     The present invention relates to medical devices and methods for accessing an anatomical space of the body. More specifically, the invention relates to devices and methods for accessing the pericardial space of the heart in a minimally-invasive manner.  
       BACKGROUND  
       [0002]     The human heart is enveloped within a tissue structure referred to as the pericardium, which comprises two major parts. The inner layer of the pericardium lies immediately over the myocardium (heart muscle) and is referred to as the visceral pericardium or epicardium. The outer layer, forming a sac around the visceral pericardium, is referred to as the parietal pericardium. Normally these two layers lie in close contact with each other and are separated only by a thin layer of pericardial fluid, which allows the heart to move within the sac with minimal friction. The potential space between the visceral and parietal pericardia is referred to as the pericardial space. The visceral pericardium is typically referred to as the epicardium and the parietal pericardium is typically referred to as the pericardium. This naming convention will be used hereafter.  
         [0003]     Access to the pericardial space is necessary for a variety of medical procedures, including treatment of infections, injuries and heart defects. For example, cardiac rhythm management systems such as pacemakers, implantable pulse generators, and implantable cardioverter defibrillators include leads having electrodes for sensing and stimulating the heart. These leads can be deployed inside or outside the heart. In the latter case, the pericardial space must be traversed to reach the epicardium or myocardium for lead implantation and attachment.  
         [0004]     Part of the challenge in accessing the pericardial space stems from its minimal thickness. When making an incision or perforation in the pericardium, it is preferable to avoid also puncturing the underlying epicardium and damaging the myocardium or a coronary vessel. However, the close proximity of the epicardium to the pericardium makes this difficult. Another important consideration is the widespread trend toward minimally-invasive surgical techniques, which generally offer a host of advantages including lower costs and fewer complications.  
         [0005]     Other known methods of accessing the pericardial space include (a) use of an endoscopic grasper and scissors or (b) careful needle placement under fluoroscopic vision. The grasper and scissors approach requires multiple surgical access ports, while the needle technique has resulted in many reported incidents of myocardial puncture, some requiring emergency surgery. Various exemplary methods for accessing this space are disclosed in U.S. Pat. Nos. 4,865,037 and 5,033,477 to Chin et al.  
         [0006]     There exists a need for improved, efficacious methods and instruments for penetrating the pericardium and thereby accessing the pericardial space that minimize the risk of damaging other tissues of the heart. There is a further need for such methods that are compatible with minimally-invasive surgical techniques would be especially desirable.  
       SUMMARY  
       [0007]     In one embodiment, the present invention is a method for accessing a pericardial space located between a pericardium and an epicardium. An adhesive grip is attached to a surface of the pericardium. The adhesive grip is grasped. The adhesive grip is drawn away from the epicardium, thereby enlarging the pericardial space. The pericardium is perforated with a perforation implement. In one embodiment, the adhesive grip further comprises an adhesive and attaching the adhesive grip includes curing the adhesive. According to another embodiment, the adhesive grip further comprises an adhesive and a gripping element.  
         [0008]     In another embodiment, the present invention is a method for accessing a pericardial space located between a pericardium and an epicardium. A first end of a gripping tube is attached to a surface of the pericardium with an adhesive. The gripping tube is withdrawn from the epicardium, thereby enlarging the pericardial spaced. The pericardium is perforated with a perforation element. According to one embodiment, attaching the first end of the gripping tube includes applying adhesive to at least one of the first end of the gripping tube and the surface of the pericardium, contacting the first end of the gripping tube with the surface of the pericardium and curing the adhesive. According to another embodiment, the first end of the gripping tube includes a detachable tip.  
         [0009]     According to yet another embodiment, the present invention is a pericardial access system for facilitating access to a pericardial space between a pericardium and an epicardium. The system includes a tubular body and a perforation instrument for perforating the pericardium. The tubular body defines an inner lumen adapted for slidably receiving a medical device therethrough and has a distal surface adapted for adhesively coupling to the pericardium. The perforation instrument is adapted to slide within the inner lumen and extend beyond the distal surface.  
         [0010]     According to still another embodiment, the present invention is a pericardial grip that can be grasped for purposes of manipulating a pericardium. The pericardial grip includes a graspable element and an adhesion means for facilitating adhesion of the graspable element to an exterior surface of the pericardium.  
         [0011]     This summary is not intended to describe each embodiment or every implementation of the present invention. Advantages and a more complete understanding of the invention will become apparent upon review of the detailed description and claims in conjunction with the accompanying drawings. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0012]      FIG. 1  is an illustration of a heart having an adhesive grip attached to the pericardium in accordance with a first embodiment of the present invention.  
         [0013]      FIG. 2  is a partially-sectioned side view of the adhesive grip as shown in  FIG. 1  along with associated surgical tools in relation to the underlying anatomic layers of the heart.  
         [0014]      FIG. 3  is a flowchart showing a method of accessing a pericardial space using the adhesive grip as shown in  FIG. 2 .  
         [0015]      FIG. 4  is a partially-sectioned side view of the adhesive grip as shown in  FIG. 2  with a pair of forceps engaging the adhesive grip such that the pericardium drawn away from the heart.  
         [0016]      FIG. 5  is a partially-sectioned side view of the adhesive grip, pericardium, and forceps as shown in  FIG. 4 , with a perforation implement perforating the pericardium.  
         [0017]      FIG. 6  is a partially-sectioned side view of the adhesive grip, forceps, and perforation implement as shown in  FIG. 5 , with a guide wire advanced into the pericardial space.  
         [0018]      FIG. 7  is a partially-sectioned side view of an adhesive grip including a suture loop and associated surgical tools in relation to the underlying anatomic layers of the heart in accordance with a second embodiment of the present invention.  
         [0019]      FIG. 8  is a flowchart detailing a method of accessing a pericardial space using the adhesive grip as shown in  FIG. 7 .  
         [0020]      FIG. 9  is a partially-sectioned side view of an adhesive grip including a suture loop with an anchor with associated surgical tools in relation to the underlying anatomic layers of the heart in accordance with a third embodiment of the present invention.  
         [0021]      FIG. 10  is a flowchart detailing a method of accessing a pericardial space using the adhesive grip as shown in  FIG. 9 .  
         [0022]      FIG. 11  is a perspective view of an adhesive grip in accordance with another embodiment of the present invention.  
         [0023]      FIG. 12  is a flowchart detailing a method of accessing a pericardial space using the adhesive grip as shown in  FIG. 11 .  
         [0024]      FIG. 13  is a partially-sectioned side view showing the adhesive grip of  FIG. 11  attached to a pericardium, with the underlying anatomic layers of the heart.  
         [0025]      FIG. 14  is a partially-sectioned side view of the adhesive grip and anatomic layers of the heart as shown in  FIG. 13 , with the pericardium drawn away from the heart.  
         [0026]      FIG. 15  is a partially-sectional side view of the adhesive grip and anatomic layers of the heart as shown in  FIG. 14 , with a slidably mounted perforation implement perforating the pericardium.  
         [0027]      FIG. 16  is a side perspective view of an adhesive grip in accordance with another embodiment of the present invention.  
         [0028]      FIG. 17  is a side perspective view of the adhesive grip of  FIG. 16  and further including a plurality of flexible tabs at a distal end.  
         [0029]      FIG. 18  is a side perspective view of the adhesive grip of  FIG. 17  mounted on the pericardium.  
         [0030]      FIG. 19  is a side sectional view of an adhesive grip including a detachable inner tip in accordance with another embodiment of the present invention.  
         [0031]      FIG. 20  is a side sectional view of an adhesive grip including an detachable outer tip in accordance with one embodiment of the present invention.  
         [0032]      FIG. 21A  is a side perspective view of an adhesive grip including a plurality of adhesive lumens in accordance with another embodiment of the present invention.  
         [0033]      FIG. 21B  is a cross-sectional view of the adhesive grip of  FIG. 21A  taken along line B-B.  
         [0034]      FIG. 21C  is a cross-sectional view of the adhesive grip of  FIG. 21A  taken along line C-C.  
         [0035]      FIG. 22  is a flowchart detailing a method of accessing a pericardial space with the adhesive grip of  FIGS. 21A-21C .  
         [0036]      FIG. 23  is a partially-sectioned view of the adhesive grip of  FIGS. 21A-21C  in relation to the anatomic layers of the heart.  
         [0037]      FIG. 24  is a partially-sectioned view of the adhesive grip of  FIG. 23  adhered to the pericardium.  
         [0038]      FIG. 25  is a partially-sectioned view of the adhesive grip of  FIGS. 23 and 24  including a perforation implement.  
         [0039]      FIG. 26  is a partially-sectioned view of an adhesive grip and a perforation instrument disposed within a sleeve.  
         [0040]      FIG. 27  is a partially-sectioned view of the adhesive grip of  FIG. 26  in which the perforation instrument is removed. 
     
    
       [0041]     While the invention is amenable to various modifications and alternative forms, specific embodiments have been shown by way of example in the drawings and are described in detail below. The intention, however, is not to limit the invention to the particular embodiments described. On the contrary, the invention is intended to cover all modifications, equivalents, and alternatives falling within the scope of the invention as defined by the appended claims.  
       DETAILED DESCRIPTION  
       [0042]      FIG. 1  is a general schematic illustration of an adhesive grip  10 , in accordance with a first embodiment of the present invention, in relation to a heart  20 . As shown in greater detail in the partially-sectioned side view of  FIG. 2 , the adhesive grip  10  includes a bolus  12  of bio-compatible adhesive that has been deposited on a pericardium  22  of the heart  20 . In the illustrated embodiment, the bolus  12  solely or substantially forms the grip  10 . However, other materials and elements can be used in adhesive grips in other embodiments such as those described below. A pericardial space  24  lies opposite the pericardium  22  and is bounded by an epicardium  26  on its far side. The epicardium  26  contacts a myocardium  28  on the side opposite the pericardial space  24 . The upper left portion of  FIG. 1  shows a pair of forceps  30  having a tip  32  for grasping the adhesive grip  10 . The upper right portion of  FIG. 1  shows a perforation implement  40  with a hollow sharpened element  42 .  
         [0043]     The bolus  12  may be formed using a biocompatible adhesive formed of a high viscosity gel. The bio-compatible adhesive used to form bolus  12  can be characterized by a high viscosity so that it will maintain a form after deposition. Non-limiting examples of adhesives that can be used for this purpose include BioGlue® available from CryoLife, Inc. of Kennesaw, Ga.), fibrin sealants, cyanoacrylates, bovine collagen/thrombin, and polyethylene glycol polymers. Degradable or absorbable bio-compatible adhesives may be used, thereby leaving no permanent residual. Alternately, any permanent residual of a bio-compatible adhesive may be naturally encapsulated and rendered inert. In addition, drug-eluting adhesives can be employed to deliver a therapeutic benefit to the heart. Such adhesives may be cured or hardened via exposure to the environment, under the application of light, RF, or through the addition of a curing agent. An appropriate adhesive might be one that cures at body temperatures. Another appropriate adhesive might be one that is thermo-set. Another appropriate light curing adhesive is the acrylic adhesive Loctite® 3321 (available from Loctite® of Rocky Hill, Conn.). Other adhesives may cure through the application of particular radio frequency or may  
         [0044]     The flowchart of  FIG. 3  shows one embodiment of a method  50  for accessing the pericardial space using the adhesive grip  10  shown in  FIG. 2 . As shown in  FIG. 3 , a minimally-invasive surgical technique is used to gain access to the pericardium  22  (block  52 ). Any appropriate conventional or otherwise known technique can be used for this purpose. An exemplary pericardial access technique is described in published U.S. patent application Ser. No. 10/140,309 to Chin et al., which is herein incorporated by reference. The adhesive grip  10  is attached to the accessed pericardium  22 . This includes the steps of depositing the bolus  12  of adhesive on the pericardium  22  (block  54 ) and curing or otherwise hardening the bolus  12  of adhesive (block  56 ). Any efficacious deposition technique can be used here, such as application of the adhesive with a swab or paddle, or extrusion of the adhesive from a tubular applicator. The length of curing time will depend on the type of adhesive used and may depend on factors such as, for example, the addition of a curing agent, the presence of moisture, illumination with light, or application of pressure.  
         [0045]     As shown in  FIG. 4 , after the bolus  12  of adhesive has cured, the forceps  30  or another suitable instrument is used to grasp the adhesive grip  10  (block  58 ) and the grip is drawn away from the heart  20  to enlarge the pericardial space  24  (block  60 ). With the pericardium  22  withdrawn, a perforation implement  40  is advanced through the pericardium  22  to perforate it (block  62 ) as illustrated in  FIG. 5 . Perforating the pericardium  22  while the pericardium  22  is drawn away from its nominal position in close proximity to underlying heart tissues allows the perforation to be performed with low risk of puncturing or otherwise damaging other tissues.  
         [0046]     A guide wire  70  can then be passed through a lumen in the implement  40  and the implement withdrawn (block  64 ), as shown in  FIG. 6 . The forceps  30  can then be returned toward the heart  20  and the grasp on the adhesive grip  10  released (block  66 ).  
         [0047]      FIG. 7  is a partially-sectioned side view of an adhesive grip  80  in accordance with another embodiment of the present invention. In this figure, the anatomy is identical to that of  FIG. 2 , including a pericardium  22 , pericardial space  24 , epicardium  26 , and myocardium  28  of a heart  20 . In the present embodiment, the adhesive grip  80  includes a loop  84  of bio-compatible material, such as is known in the art of sutures, embedded in a bolus  82  of bio-compatible adhesive that has been deposited on the pericardium  22 . The adhesive used for bolus  82  can be the same as or similar to those used in connection with grip  10  described above. The upper left portion of  FIG. 7  shows a surgical tool  90  with a hook-shaped distal end  92  that can be used to grasp the suture loop  84 . The upper right portion of  FIG. 7  shows a perforation implement.  
         [0048]     The flowchart of  FIG. 8  shows a method  100  for accessing the pericardial space  24  using the adhesive grip  80  shown in  FIG. 7 . A minimally-invasive surgical technique is used to gain access to the pericardium  22  (block  102 ). The adhesive grip  80  is attached to the accessed pericardium  22 . This includes the steps of depositing the bolus  82  of adhesive on the pericardium  22  (block  104 ), embedding the suture loop  84  in the bolus  82  (block  106 ), and curing the adhesive of the bolus  82  (block  108 ). After the bolus  82  of adhesive has cured, the hooked surgical tool  90  or another suitable instrument is used to grasp the adhesive grip  80  by hooking loop  84  with hooked distal end  92  of surgical tool  90  (block  110 ) and the grip  80  is drawn away from the heart  20  to enlarge the pericardial space  24  (block  112 ). With the pericardium  22  withdrawn, a perforation implement  40  is advanced through the pericardium  22  to perforate it (block  114 ). A guide wire can then be passed through the lumen in the implement  40  and the implement  40  withdrawn (block  116 ). The hooked tool  90  can then be returned toward the heart  20  and the adhesive grip  80  released (block  118 ).  
         [0049]      FIG. 9  is a partially-sectioned side view of an adhesive grip  120  in accordance with a third embodiment of the present invention. In  FIG. 9 , the anatomy is identical to that of  FIGS. 2 and 7 , including a pericardium  22 , pericardial space  24 , epicardium  26 , and myocardium  28  of a heart  20 . In the present embodiment, the adhesive grip  120  includes a suture loop  124  attached to an anchor  126  embedded in a bolus  122  of adhesive that has been deposited on the pericardium  22 . As in the other embodiments, all materials used are of a bio-compatible nature. The adhesive used for bolus  122  can be the same as or similar to those used in connection with grips  10  and  80  described above. For the anchor  126 , possible materials include silicone, polyurethane and common moldable suture materials such as polyethylene, polypropylene, and polyvinylidene fluoride, as well as previously-cured adhesive of the same type used for the bolus  122 . The anchor  126  provides increased surface are to prevent the loop  124  from pulling through the cured bolus  112  of adhesive, due to local repetitive stresses. The upper left portion of  FIG. 9  shows a surgical tool  90  with a hook-shaped distal end  92  that can be used to grasp the suture loop  124 . The upper right portion of  FIG. 9  shows a perforation implement  40 .  
         [0050]     The flowchart of  FIG. 10  shows a method  130  for accessing the pericardial space using the adhesive grip  120  shown in  FIG. 9 . A minimally-invasive surgical technique is used to gain access to the pericardium  22  (block  132 ). The adhesive grip  120  is attached to the accessed pericardium  22 . This includes the steps of depositing the bolus  122  of adhesive on the pericardium  22  (block  134 ), embedding the anchor  126  attached to the suture loop  124  in the adhesive bolus  122  (block  136 ), and curing the adhesive of the bolus  122  (block  138 ). After the bolus  122  of adhesive has cured, the hooked surgical tool  90  or another suitable instrument is used to grasp the adhesive grip  120  (block  140 ) and the grip  120  is drawn away from the heart  20  to enlarge the pericardial space  24  (block  142 ). With the pericardium  22  withdrawn, a perforation implement  40  is advanced through the pericardium  22  to perforate it (block  144 ). A guide wire can then be passed through the lumen in the implement  40  and the implement withdrawn (block  146 ). The hooked tool  90  can then be returned toward the heart  20  and the grasp on the adhesive grip  120  released (block  148 ).  
         [0051]      FIG. 11  is a perspective view of an adhesive grip  150  in accordance with another embodiment of the present invention. The grip  150  includes a substantially hollow tubular body  152 . In one embodiment, a distal surface  156  of the tubular body  152  is textured so as to provide greater surface area for adhesion. A hollow, sharpened perforation implement  162  is mounted slidably within a central lumen  163  of the tubular body  152 . Tubular body  152  has a substantially greater diameter and/or a greater wall thickness in comparison to the grips of the preceding embodiments so as to increase the surface area available for adhesion.  
         [0052]     The flowchart of  FIG. 12  shows a method  170  for accessing the pericardial space using the adhesive grip  150  shown in  FIG. 11 . A minimally-invasive surgical technique is used to gain access to a pericardium  22  (block  172 ). The grip  150  is attached adhesively to the pericardium  22  as depicted in  FIG. 13 . This includes the steps of applying an adhesive  164  to the distal surface  156  of the grip  150  (block  174 ), placing or contacting the grip  150  to an appropriate location on the pericardium  22  (block  176 ), and curing the adhesive  164  (block  178 ). After the adhesive  164  has cured, the grip  150  is drawn away from the heart  20  to enlarge the pericardial space  24  (block  180 ), as shown in  FIG. 14 . With the pericardium  22  withdrawn, the perforation implement  162  is advanced through the lumen  163  to perforate the pericardium  22  (block  182 ), as illustrated in  FIG. 15 . A guide wire  166  can then be passed through a lumen in the implement  162  into the pericardial space  24  and the implement  162  withdrawn (block  184 ).  
         [0053]     Rather than applying adhesive  164  to the grip  150 , a bolus of adhesive may be deposited on the pericardium  22 , and the distal surface  156  of the grip  150  contacted with the adhesive on the percardium  22  before curing. Following the procedure, the adhesive bond is broken and the grip  150  is detached from the pericardium  22 . A cutting tool may be used to detach the grip  150  from the adhesive  164 .  
         [0054]      FIG. 16  is a perspective view showing yet another embodiment of an adhesive grip  200  similar to the adhesive grip  150  shown in  FIGS. 11-15  but featuring a coaxial construction. In this embodiment, the grip  200  includes an inner substantially hollow tubular body  202  slidably disposed in an outer substantially hollow tubular body  204 . In reference to method  170  described above and shown in  FIG. 12 , during step  174  the adhesive would be applied only to a distal surface  206  of the outer tubular body  204 . In step  176 , the inner tubular body  202  would be brought into contact with the pericardium  22  before the outer tubular body  204  would contact the pericardium  22 . Applying the grip  200  in this manner would prevent adhesive from entering a lumen  208  of the inner tubular body  202  and potentially interfering with the perforation of the pericardium  22 . Additionally, during the removal of the adhesive grip  200  from the pericardium  22  (block  184 ), the inner tubular body  202  may be used to stabilize the pericardium  22  as the outer tubular body  204  is manipulated for removal.  
         [0055]     In still another embodiment, the adhesive grip  200  is used, but in reference to method  170  described above and shown in  FIG. 12 , during step  174 , the adhesive is delivered to the distal surface  206  through an annular lumen  210  defined between the inner tubular body  202  and outer tubular body  204 . The adhesive is injected or pumped along the annular lumen  210 . After a small amount of adhesive has reached the distal end  206  of the outer tubular body  204 , inner tubular body  202  and outer tubular body  204  are brought into contact with the pericardium  22  simultaneously. The adhesive is allowed to cure as previously described.  
         [0056]      FIGS. 17 and 18  are perspective views of yet another embodiment of an adhesive grip  220  that is generally similar to the adhesive grip  150  shown in  FIGS. 11-16 . In this embodiment, the adhesive grip  220  includes a substantially hollow tubular body  221  provided with a plurality of cuts  224  at a distal end  222  to divide the distal end  222  into a plurality of flexible tabs  226 . In  FIG. 17  the tabs  226  are shown slightly flared or splayed radially outwardly from the axis of the grip  220 . In reference to method  170  described above and shown in  FIG. 12 , during step  176 , the grip  220  would be compressed against the pericardium  22 , causing the tabs  226  to flare outward and flatten against the pericardium  22 , as is shown in  FIG. 18 , and hence provide greater surface area for adhesive attachment. The tabs  226  are optionally provided by a flared silicon rubber material component. Optionally, the thickness of the tabs  226  is less than the thickness of the remainder of the grip  220 . This encourages an inner surface of the tabs  226  to compress and flare radially outwardly against the pericardium  22 . The tabs  226  may also be formed from a fabric material, for example, Dacron®. The adhesive grip  220  optionally has a coaxial construction, including an inner tubular member (not shown) as described with respect to the previous embodiment and shown in  FIG. 16 .  
         [0057]     In any of the preceding embodiments described in relation to  FIGS. 11-18 , the installed adhesive grip may subsequently serve as a means of permanently or semi-permanently affixing an implanted medical device, such as a lead, to the pericardium  22 . The lead is fixed to the installed adhesive grip by, for example, crimping the grip to the lead proximal to the surface of the pericardium  22 . The adhesive bond may be reinforced with a suture to increase the fixation of the adhesive grip to the pericardium  22 .  
         [0058]      FIG. 19  shows another embodiment of an adhesive grip  240  that is generally similar to the adhesive grips shown in  FIGS. 11-18 . The adhesive grip  240  includes a substantially hollow tubular body  242  provided with a detachable distal tip  244  which may serve to affix an implantable medical device, such as a lead, to the pericardium  22 . The detachable distal tip  244  includes a distal surface  245  which may be adhered to the pericardium  22  according to any of the embodiments as previously described. The lead is advanced through the tubular body  242  and affixed to the detachable tip  244  by, for example, crimping. The tubular body  242  is then detached from the tip  244  and removed.  
         [0059]     In one embodiment, as is shown in  FIG. 19 , the detachable tip  244  is held deformably inside the tubular body  242 . Once the detachable tip  244  is adhered to the pericardium  22 , the longer tubular body  242  is pulled free of the now anchored tip  244 . The detachable tip  244  may be forced from the remainder of the tubular body  242  by passing an inner semi-rigid tube (shown in dashed lines) through the tubular body  242  to push the tip  244  out of the end of the tubular body  242 . According to another embodiment, the tip  244  is deformably held outside the end of the tubular body  242 , as is shown in  FIG. 20 . Once the detachable tip  244  is adhered to the pericardium  22 , the longer tubular body  242  is pulled free of the now anchored tip  244 . An outer semi-rigid tube (shown in dashed lines) may be passed over the tubular body  242  to force the tip  244  from the end of the tubular body  242 .  
         [0060]     In addition to crimping, the tip  244  could be gently attached to the lead through the use of an internal lining of fabric, for example, Dacron®. The fit between the lead and the fabric lining would be sufficient to frictionally engage the lead to the tip  244 . The fabric may be chosen to promote desired tissue ingrowth, thereby providing a more natural fixation of the tip  244  and lead at the tissue site.  
         [0061]      FIGS. 21A-21C  show another embodiment of an adhesive grip  260  that is generally similar to the adhesive grips shown in FIGS.  11 - 18 - 20 . As shown in  FIG. 21A , adhesive grip  260  includes a tubular body  261  provided with an atraumatic tip  262  at a distal end  264 . The tubular body  261  includes a main lumen  266  extending through a port  268  near the distal tip  262  and a secondary lumen  270  terminating in a secondary port  272  in a side wall of the tubular body  261  proximal to the distal tip  262  (compare  FIGS. 21B and 21C ). Main lumen  266  is adapted to slidably receive medical instruments, including guide wires, needles, forceps, endoscopes and the like. Secondary lumen  270  is adapted to slidably receive a perforation instrument as previously described. Grip  260  further includes an adhesive delivery lumen  274  terminating in a plurality of adhesive ports  276  in a side wall of the tubular body  261  proximal to the distal tip  262  and distal to the secondary port  272 . Alternately, rather than a single adhesive delivery lumen  274  provided with a plurality of ports  276 , grip  260  is provided with a plurality of adhesive delivery lumens each terminating in a single port positioned adjacent one another.  
         [0062]      FIG. 22  shows a method  280  for accessing the pericardial space  24  using the adhesive grip  260  of  FIGS. 21A-21C . In use a minimally-invasive surgical technique is used to gain access to a pericardium  22  (block  282 ). The grip is advanced to the pericardium  22  (block  284 ). The grip  260  is attached adhesively to the pericardium  22  as depicted in  FIGS. 22 and 23 . This includes the steps of positioning the grip on the pericardium  22  (block  286 ), forcing adhesive through ports  276  to the pericardium  22 , as is shown in  FIG. 23  (block  288 ) and curing the adhesive (block  290 ). The grip  260  is withdrawn, separating the pericardium  22  from the epicardium  26  and enlarging the pericardial space  24 , as is shown in  FIG. 25  (block  292 ). With the pericardium  22  withdrawn, a perforation implement is advanced through the secondary lumen  270  to perforate the pericardium  22 , as is shown in  FIG. 25  (block  294 ).  
         [0063]     The grip  260  may be withdrawn axially from the surface of the pericardium  22 , as is shown in  FIG. 25 . Alternately, the grip  260  is pivoted or rotated away from the pericardium  22  to drawn a portion of the pericardium  22  away from the epicardium  26 . In such an embodiment, the perforation element can be angularly offset from the lumen  270  when advanced to perforate the pericardium  22 .  
         [0064]     In the preceding embodiments, a hollow perforation instrument is used to perforate the raised pericardium  22 , followed by insertion of an element such as a guide wire through the perforation instrument into the pericardial space. Other instruments and techniques may be used to perforate the raised pericardium  22 . In one example, as is shown in  FIGS. 26 and 27 , a perforation instrument  300  is slidably disposed within an open sleeve  302  so that a distal pointed end  304  of the perforation instrument  300  protrudes from a distal end  306  of the sleeve  302 . The perforation instrument  300  is used to perforate the raised pericardium  22  as previously described. The perforation instrument  300  is advanced until the distal end  306  of the sleeve  302  is located within the pericardial space  24 . The perforation instrument  300  is then withdrawn while the sleeve  302  is held in place. Other payloads, for example, leads, may be then advanced through the sleeve  302  into the pericardial space  24 .  
         [0065]     Although the preceding embodiments are generally shown in relation to accessing the pericardial space  24 , such methods and devices as described above may also be employed to access other tissue layers. For example, in the treatment of ischemias and aneurism, it may be desirable to access spaces between anatomic layers of the brain, including the dura. Such methods and devices may also be used to access the peritoneum. The methods and devices of the preceding embodiments may be used to access virtually any anatomic layer.  
         [0066]     Various modifications and additions can be made to the exemplary embodiments discussed without departing from the scope of the present invention. Whereas the particular example of accessing the pericardial space has been used for illustrative purposes, it will be readily apparent to one skilled in the art that similar procedures in other anatomies may similarly benefit from the present invention. Accordingly, the scope of the present invention is intended to embrace all such alternatives, modifications, and variations as fall within the scope of the claims, together with all equivalents thereof.