Abstract:
A cannulation device is disclosed, having a fixed blade, a retractable wedge, and an adjustment nut for mating with a cannula or a cannula assembly. Another cannulation device is disclosed, having a tube with proximal and distal ends. The fixed blade, coupled to the distal end of the tube, comprises a transition edge configured to cover a lead edge of a cannula. The cannulation device has a control rod movable within the tube; a retractable wedge; an actuator coupled to the control rod; and is configured to move the retractable wedge from a piercing position, where the retractable wedge is aligned with the fixed blade, to a retracted position where the retractable wedge has been retracted within the tube. The cannulation device has a cannula adapter and an adjustment nut movable to change a distance between the adjustment nut and the fixed blade.

Description:
RELATED APPLICATION 
       [0001]    This patent application claims priority to U.S. Provisional Patent Application No. 62/281,768 filed Jan. 22, 2016 and entitled “CANNULATION DEVICE AND METHODS THEREOF”. The 62/281,768 application is hereby incorporated by reference in its entirety. 
     
    
     FIELD 
       [0002]    The claimed invention relates to surgical cannulation, and more specifically a cannulation device and methods thereof. 
       BACKGROUND 
       [0003]    Various types of surgery require a surgeon to place a cannula within a vessel, such as the aorta, in order to gain fluid access to the vessel. For example, in many cardiac surgeries, blood returning to the heart may be diverted to one or more cannulas for removal from the patient&#39;s body in order to pass the blood through a cardio pulmonary bypass (CPB) machine that reoxygenates the blood before returning the blood to the aorta on the output side of the heart. It is desirable to minimize the amount of time it takes to establish cannulation so that CPB may be established without undue delay and so that surgery times may be reduced in order to improve patient outcomes and reduce surgical team fatigue. Unfortunately, at odds with this desire is the reality that more and more surgeries are being done with minimally invasive techniques to reduce patient trauma and speed recovery times. The small access sites afforded surgeons with minimally invasive techniques may either make cannulation difficult (time consuming) or may prevent surgeons from using the minimally invasive techniques in the first place. Therefore, it would be desirable to have a cannulation device and methods which would enable surgeons to place a cannula efficiently in a vessel while operating through a minimally invasive surgical access site. 
       SUMMARY 
       [0004]    A cannulation device is disclosed. The cannulation device has a fixed blade, a retractable wedge, and an adjustment nut for mating with a cannula or a cannula assembly. 
         [0005]    Another cannulation device is disclosed. The cannulation device has a tube having a proximal end and a distal end. The cannulation device also has a fixed blade coupled to the distal end of the tube. The fixed blade comprises a transition edge configured to cover a lead edge of a cannula. The cannulation device further has a control rod movable within the tube and a retractable wedge coupled to the control rod. The cannulation device also has an actuator coupled to the control rod and configured to move the retractable wedge from a piercing position where the retractable wedge is aligned with the fixed blade to a retracted position where the retractable wedge has been retracted within the tube. The cannulation device further has an adjustment nut movable to change a distance between the adjustment nut and the fixed blade. The cannulation device also has a cannula adapter. 
         [0006]    A method of cannulation is disclosed. While retracting a retractable wedge, a fixed blade is pushed past a distal end of a cannula, such that a transition edge of the fixed blade clears a leading edge on the distal end of the cannula. After the fixed blade clears the leading edge of the cannula, the retractable wedge is extended out of the distal end of the cannula to a piercing position in alignment with the fixed blade which provides cover for the leading edge of the cannula. Then the fixed blade and retractable wedge are used to pierce a vessel so that the lead edge of the cannula follows into the vessel. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]      FIG. 1  is a perspective view of one embodiment of a cannulation device. 
           [0008]      FIG. 2  is a partially exposed perspective view of the cannulation device of  FIG. 1 . 
           [0009]      FIG. 3  is an exploded perspective view of the cannulation device of  FIG. 2 . 
           [0010]      FIG. 4A  is an embodiment of a cannula assembly. 
           [0011]      FIG. 4B  is an exploded side view of the cannula assembly of  FIG. 4A . 
           [0012]      FIG. 4C  is a side cross-sectional view of a cannula adapter. 
           [0013]      FIGS. 5A-5G  schematically illustrate a surgical situation and example of using the cannulation device with the cannula assembly in order to place the cannula into a vessel. 
           [0014]      FIG. 6  illustrates another embodiment of a cannulation device in a partially exposed perspective view. 
           [0015]      FIG. 7  is an exploded perspective view of the cannulation device of  FIG. 6 . 
       
    
    
     DETAILED DESCRIPTION 
       [0016]      FIG. 1  is a perspective view of one embodiment of a cannulation device  20 . The cannulation device  20  has an actuator handle  22  that is pivotably coupled to a housing  24 . A tube  26  is coupled to the housing  24 , and a fixed blade  28  is coupled to the tube  26 . Under the fixed blade  28 , a retractable wedge  30  is axially moveable from the fully extended position shown in  FIG. 1  to a retracted position which will be illustrated later in this discussion. An adjustment nut  32  is positioned around the tube  26 . 
         [0017]      FIG. 2  is a partially exposed perspective view of the cannulation device  20  of  FIG. 1 . A portion of the housing  24  has been removed from  FIG. 2  in order to show the components of the device which were covered therein in this embodiment. The tube  26 , which passes through the adjustment nut  32 , is coupled to an adapter  34  which is held by the housing  24 . The adapter  34  has a channel therein (not visible in this view) through which a proximal end  36  of a control rod  58  has been passed. The control rod  58  is coupled to or may be formed continuously with the retractable wedge  30 . In this embodiment, the control rod  58  is coupled to a reverse gear  38 . The reverse gear  38  is moveable by a corresponding lever gear  40  which is part of the actuator handle  22 . A spring  42  coupled between a fixed spring anchor  44  and the actuator handle  22  such that the handle  22  is biased away from a grip  46  formed by the housing  24 . With the handle  22  in the position shown in  FIGS. 1 and 2 , the retractable wedge  30  is not retracted, but is, instead, in a piercing position. 
         [0018]      FIG. 3  is an exploded perspective view of the cannulation device  20  of  FIG. 2 . The proximal end  50  of the tube  26  is passed through a hole  52  in the adjustment nut  32  and coupled inside a tube receiver end  54  of the adapter  34 . Threads inside the adjustment nut  32  (threads not visible in this view) correspond to adapter threads  56  on the adapter  34 , and the adjustment nut  32  may be threaded onto the adapter  34 . In this embodiment, the retractable wedge  30  is formed continuously with the control rod  58  as part of the same part. In other embodiments, these portions could be separate parts and would need to be coupled. The fixed blade  28  is placed against the distal end of the retractable wedge tip  30 , while the proximal end  36  of the control rod  58  is inserted into the tube  26 , and passed out through the adapter  34 . In this embodiment, a key  28 A on the fixed blade  28  engages a key receiver  26 A in the tube  26  in order to prevent the fixed blade from sliding relative to the tube  26 . A keyed portion  60  on the proximal end  36  of the control rod  58  is coupled to a control rod interface  62  on the reverse gear  38  after passing through the adapter  34 . Reverse gear axles  64  are mated with corresponding reverse gear axle bosses  66  on the housing  24 . Given the exposed perspective of  FIG. 3 , it should be noted that the visible reverse gear axle  64  mates with a boss in the housing that has been removed to expose the working parts (and therefore is not visible). Similarly, the visible reverse gear axle boss  66  mates with a gear axle  64  which is not visible from this perspective. 
         [0019]    With the retractable wedge  30  fully extended in a piercing position, the actuator handle  22  can be pivotably coupled to the housing  24  while the handle  22  is fully extended. In doing this, axles  48  of the handle  22  are placed within corresponding lever axle bosses  68  of the housing  24 . The spring  42  is coupled between a spring attachment point  70  on the handle  22  and a fixed spring anchor  44  on the housing  24 . 
         [0020]    The adapter  34  has housing interface wings  72  which mate with corresponding features (not shown, but known to those skilled in the art) on the inside of the housing  24 . Although only one half of the housing  24  is shown in this exposed exploded view, it should be understood that a corresponding half of the housing (not shown) would couple with the visible housing  24  half to hold the adapter  34  in place while providing for pivotable movement of the actuator handle  22  and reverse gear  38  so that the retractable wedge  30  may be moved as described further below. 
         [0021]    The cannulation device  20  is intended to interact with a cannula assembly  74 , such as the one schematically illustrated in the side view of  FIG. 4A . In the embodiment of  FIG. 4A , the cannula assembly  74  has a cannula  76  and a cannula adapter  78 . Different embodiments and sizes of the cannulation device, discussed previously, may be configured to work with a variety of types of cannulas  76 . As just one non-limiting example, the cannula  76  used herein is a Medtronic 71422 Femoral Venous Cannula. In this embodiment, the cannula adapter  78  includes a strain relief  80 , a hub body  82 , and a sealing cap  86 . The hub body  82  may include a fluid port  84  which may be selectively capped or coupled to tubing in order to provide fluid access. The sealing cap  86  has a device receiver  88  which is sized to accommodate the tube  26  of the cannulation device (not shown in this view).  FIG. 4B  is an exploded side view of the cannula assembly  74 .  FIG. 4C  is a side cross-sectional view of the cannula adapter  78 . 
         [0022]      FIGS. 5A-5G  schematically illustrate a surgical situation and example of using the cannulation device  20  with the cannula assembly  74  in order to place the cannula  76  into a vessel. Portions of the cannulation device  20  and cannula assembly  74  are shown in quasi cross-sectional or transparent views so that hidden movements and covered parts can be seen. In  FIG. 5A , the actuator handle  22  is in its resting position, and the retractable wedge  30  is in a corresponding piercing position. The tube  26  of the cannulation device  20  is aligned with the device receiver  88  of the sealing cap  86  on the cannula assembly  74 . As illustrated in  FIG. 5B , the handle  22  is moved  90  towards the grip  46 , causing the retractable wedge  30  to move proximally  92 . The proximal movement  92  of the retractable wedge  30  enables the fixed blade  28  to fall down, reducing the effective area presented by the combined fixed blade  28  and retractable wedge  30 . As shown in  FIG. 5C , the cannulation device  20  can be inserted  94  into the cannula assembly  74  while the retractable wedge  30  is retracted. As shown in  FIG. 5D , the handle  22  can be released  96 , causing the wedge  30  to move distally out the end of the cannula  76 , pushing the fixed blade  28  back to its original alignment. A vessel  98  is schematically illustrated in side cross-sectional view, waiting to be cannulated. 
         [0023]    The interface between the sealing cap  86  and the adjustment nut  32  controls how far the fixed blade  28  and wedge  30  will extend out the end of the cannula  76 .  FIG. 5D-1  is an enlarged view of the end of the cannula  76 , showing the fixed blade  28  and wedge  30  relative to the cannula  76 . The adjustment nut  32  can be rotated to ensure a smooth transition between a transition edge  100  of the fixed blade  28  and a cannula leading edge  102 . The cannula leading edge  102  is not typically strong enough or sharp enough to pierce a tissue on its own, but the transition edge  100  of the fixed blade  28  is positioned to assist with any piercing while making it easy to insert the cannula  76  into an opening created by the blade  28  and wedge  30  as will be illustrated below. 
         [0024]    Typically, surgeons will place one or more pursestring sutures around an intended cannulation site before placing the cannula. The one or more pursestring sutures are then in-place to be tightened around the cannula after it is inserted into the vessel to help maintain a tight seal of the tissue around the cannula. Since pursestring sutures are known in the art, we are not including their placement in  FIGS. 5A-5G  for simplicity. 
         [0025]    As illustrated in  FIG. 5E , the cannulation device  20  can be pushed  104  against the vessel  98 . The blade  28  and wedge  30  work together to create an incision in the vessel  98 , allowing the cannula  76  to be advanced into the vessel  98 . As illustrated in  FIG. 5F , the handle  22  can be squeezed  106  back towards the grip  46 , creating a proximal motion  108  of the retractable wedge  30  which also allows the transition edge  100  of the fixed blade  28  to fall clear of the cannula leading edge  102 . This can be seen more clearly in the enlarged view of  FIG. 5F-1 . As illustrated in  FIG. 5G , the cannulation device  20  can then be withdrawn  110  from the cannula assembly  74  which is left behind in the vessel  98 . The cannula adapter  78  may be removed from the cannula assembly  74 , while the cannula  76  is left in-place to be capped or connected to tubing, such as a line to/from a cardio-pulmonary bypass (CPB) machine. Alternately, the cannula assembly  74  may be capped or connected to such tubing, as desired. 
         [0026]      FIG. 6  illustrates another embodiment of a cannulation device  112  in a partially exposed perspective view. The cannulation device  112  has an actuator handle  22  that is pivotably coupled to a housing  24 . A tube  114  is coupled to the housing  24 , and in this embodiment, the fixed blade  116  is a continuous extension of the tube  114 . Under the fixed blade  116 , a retractable wedge  118  is axially moveable from the fully extended position shown in  FIG. 6  to a retracted position similar to the one discussed previously. An adjustment nut  120  is positioned around the tube  114 . The tube  114 , which passes through the adjustment nut  120 , is coupled to an adapter  122  which is held in this embodiment by upper and lower clamshell brackets  124 U,  124 L which are in turn held by the housing  24 . The adapter  122  has a channel therein (not visible in this view) through which a proximal end  126  of a control rod  128  has been passed. The control rod  128  is coupled to or may be formed continuously with the retractable wedge  118 . In this embodiment, the control rod  128  is coupled to a reverse gear  38  by a link  130 . The reverse gear  38  is moveable by a corresponding lever gear  40  which is part of the actuator handle  22 . A spring  42  coupled between a fixed spring anchor  44  and the actuator handle  22  such that the handle  22  is biased away from a grip  46  formed by the housing  24 . With the handle  22  in the position shown in  FIG. 6 , the retractable wedge  118  is not retracted, but is, instead, in a piercing position. 
         [0027]      FIG. 7  is an exploded perspective view of the cannulation device  112  of  FIG. 6 . The proximal end  114 P of the tube  114  is coupled inside a tube receiver  132  in the adapter  122 . Threads  134  inside the adjustment nut  120  correspond to adapter threads  136  on the adapter  122 , and the adjustment nut  120  may be threaded onto the adapter  122 . In this embodiment, the retractable wedge  118  is formed continuously with the control rod  128  as part of the same part. In other embodiments, these portions could be separate parts and would need to be coupled. The proximal end  126  of the control rod  128  is placed into the tube  114  and extended through the adapter  122  until a distal end  130 D of the link  130  can be coupled to the link end receiver  138  on the control rod  128 . The control rod  128  can then be moved within the tube  114  so that the wedge tip  118  is aligned in a piercing position with the fixed blade  116  while the proximal end  130 P of the link  130  is coupled to a link receiver  140  on the reverse gear  38 . Reverse gear axles  64  are mated with corresponding reverse gear axle bosses  66  on the housing  24 . Given the exposed perspective of  FIG. 7 , it should be noted that the visible reverse gear axle  64  mates with a boss in the housing that has been removed to expose the working parts (and therefore is not visible). Similarly, the visible reverse gear axle boss  66  mates with a gear axle  64  which is not visible from this perspective. 
         [0028]    With the retractable wedge  118  fully extended in a piercing position, the actuator handle  22  can be pivotably coupled to the housing  24  while the handle  22  is fully extended. In doing this, axles  48  of the handle  22  are placed within corresponding lever axle bosses  68  of the housing  24 . As with previous embodiments, the spring (not shown in this view) is coupled between a spring attachment point  70  on the handle  22  and a fixed spring anchor  44  on the housing  24 . 
         [0029]    The adapter  122  has facets  142  which are held by the upper and lower clamshell pieces  124 U,  124 L. The clamshell pieces  124 U,  124 L have housing interface tabs  144  which mate with corresponding features (not shown, but known to those skilled in the art) on the inside of the housing  24 . Although only one half of the housing  24  is shown in this exposed exploded view, it should be understood that a corresponding half of the housing (not shown) would couple with the visible housing  24  half to hold the adapter  122  in place while providing for pivotable movement of the actuator handle  22  and reverse gear  38  so that the retractable wedge  118  may be moved as discussed with previous embodiments. 
         [0030]    Various advantages of a cannulation device have been discussed above. Embodiments discussed herein have been described by way of example in this specification. It will be apparent to those skilled in the art that the foregoing detailed disclosure is intended to be presented by way of example only, and is not limiting. Various alterations, improvements, and modifications will occur and are intended to those skilled in the art, though not expressly stated herein. These alterations, improvements, and modifications are intended to be suggested hereby, and are within the spirit and the scope of the claimed invention. Additionally, the recited order of processing elements or sequences, or the use of numbers, letters, or other designations therefore, is not intended to limit the claims to any order, except as may be specified in the claims. Accordingly, the invention is limited only by the following claims and equivalents thereto.