Patent Publication Number: US-2022233270-A1

Title: Minimally invasive surgical device for vessel harvesting

Description:
REFERENCE TO RELATED APPLICATIONS 
     This patent application claims priority to U.S. Provisional Patent Application No. 63/140,764, filed Jan. 22, 2021 and entitled “MINIMALLY INVASIVE SURGICAL DEVICE FOR VESSEL HARVESTING” the contents of which is incorporated by reference herein in its entirety. 
    
    
     FIELD 
     The claimed invention relates to minimally invasive surgical devices, and more specifically to a minimally invasive surgical device for use in vessel harvesting. 
     BACKGROUND 
     Coronary revascularization procedures, such as the grafting of the internal thoracic artery (ITA), have shown superior long-term patency in coronary artery bypass graft (CABG) surgeries. Unfortunately, ITA harvesting typically requires the patient to undergo a sternotomy in order to enable the surgeon to access and safely dissect the targeted vessel. As a result, minimally invasive surgical approaches are being explored for ITA harvesting. One promising method for minimally invasive vessel harvesting proposes accessing the left and/or right internal thoracic artery (ITA) via a sub-xiphoid approach through a small incision at the subxiphocostal region. While such an approach through a minimally invasive incision provides excellent access to these vessels, it can be difficult to dissect the target arteries without specialized tools capable of reaching the target vessels and aiding the surgeon in the gentle separation of the vessels from surrounding tissue. Additionally, since the surgeon is harvesting vessels through a small incision with this approach, it can be difficult for the surgeon to estimate whether or not he/she has harvested enough of the target vessel to reach the point where it will be attached to the bypassed coronary artery. Therefore, it would be desirable to have a simple to use, easily manufacturable, economical, ergonomic, minimally invasive surgical device for use in vessel harvesting that is capable of being used for gentle tissue dissection and assisting with visualization of the vessel harvesting. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of one embodiment of a minimally invasive surgical device for vessel harvesting. 
         FIGS. 2A-2C  are a series of exploded views illustrating the assembly of the distal end of the minimally invasive surgical device embodiment of  FIG. 1 . 
         FIGS. 3A and 3B  are side partial cross-sectional and top partial cross-sectional views, respectively, illustrating a first operational state of the minimally invasive surgical device of  FIG. 1 . 
         FIGS. 3C and 3D  are side partial cross-sectional and top partial cross-sectional views, respectively, illustrating a second operational state of the minimally invasive surgical device of  FIG. 1 . 
         FIGS. 3E and 3F  are side partial cross-sectional and top partial cross-sectional views, respectively, illustrating a third operational state of the minimally invasive surgical device of  FIG. 1 . 
         FIGS. 4A-4C  illustrate alternate embodiments of drive mechanisms for embodiments of the minimally invasive surgical device of  FIG. 1 . 
         FIGS. 5A-5H  illustrate alternate embodiments of dissectors for a minimally invasive surgical device. 
         FIG. 6  is a perspective view of another embodiment of a minimally invasive surgical device for vessel harvesting. 
         FIG. 7  is perspective view a further embodiment of a minimally invasive surgical device for vessel harvesting. 
         FIG. 8  is a perspective view of another embodiment of a minimally invasive surgical device for vessel harvesting. 
         FIG. 9  is a perspective view of a further embodiment of a minimally invasive surgical device for vessel harvesting. 
         FIGS. 10A-10B  are perspective views of a distal end of the minimally invasive surgical device of  FIG. 9 , illustrating a closed and opened position, respectively. 
         FIG. 11  is a perspective view of another embodiment of a minimally invasive surgical device for vessel harvesting. 
         FIG. 12  is an exploded view of a distal end of the minimally invasive surgical device of  FIG. 11 . 
         FIGS. 13A and 13B  are perspective views focused on an assembled distal end of the minimally invasive surgical device of  FIG. 11  in open and closed positions, respectively. 
         FIGS. 14A and 14B  are a side partial cross-sectional view and distal end view, respectively, of the minimally invasive surgical device of  FIG. 11  in an open position. 
         FIGS. 15A and 15B  are a side partial cross-sectional view and front end view, respectively, of the minimally invasive surgical device of  FIG. 11  in a closed position. 
         FIG. 16  is an enlarged side view of a portion of the shaft of the minimally invasive surgical device of  FIG. 11 . 
         FIG. 17  illustrates one embodiment of a flexible length indicator for use with a minimally invasive surgical device for vessel harvesting. 
         FIG. 18  illustrates the flexible length indicator of  FIG. 17  attached to the distal end of an embodiment of a minimally invasive surgical device for vessel harvesting. 
         FIG. 19  schematically illustrates the flexible length indicator of  FIG. 17  being used to estimate a desired harvest vessel length while the embodied minimally invasive surgical device for vessel harvesting to which it is attached is in use for vessel dissection. 
     
    
    
     It will be appreciated that for purposes of clarity and where deemed appropriate, reference numerals have been repeated in the figures to indicate corresponding features, and that the various elements in the drawings have not necessarily been drawn to scale in order to better show the features. 
     DETAILED DESCRIPTION 
       FIG. 1  is a perspective view of one embodiment of a minimally invasive surgical device for vessel harvesting  10 . The minimally invasive vessel harvesting device  10  has a housing  12  which extends down to form a handle  14 . The device also has an actuation lever  16  pivotably coupled to the handle  14 . The minimally invasive vessel harvesting device  10  also has a shaft  18  which is coupled to the housing  12 . The minimally invasive vessel harvesting device  10  has a distal tip housing  20  on the opposite end of the shaft  18  which defines a blunt dissector  22  used in a minimally invasive surgical procedure involving the harvesting of IMA for revascularization. The blunt dissector  22  is coupled to the actuation lever  16 , and movement of the actuation lever  16  will rotate the blunt dissector  22  to achieve adjustable positioning of the blunt dissector  22  during use in a minimally invasive cardiovascular procedure such as the harvesting of internal thoracic arteries. This mechanism will be described in further detail. The blunt dissector  22  is an arcuate or curved appendage that has a smooth, atraumatic tip allowing for and enabling the gentle manipulation and separation of tissue, while preventing damage to anatomical features and structures surrounding the tissue of interest. Blunt dissection, in general, refers to an element of surgical procedure where careful separation of tissues is accomplished with the use of fingers or blunt surgical tools. The blunt dissector tip is useful in procedures related to ITA/IMA take-down or harvesting procedures. The shape, maneuverability, and atraumatic nature of the blunt dissector  22  are features that contribute to improved utility, reduced risk of harming surrounding tissue, and achieving positive results during a minimally invasive surgical procedure. While the blunt dissector  22  shown in  FIG. 1  is an atraumatic, arcuate appendage, or gentle finger, other embodiments may be blunt, partially blunt, or have partial edges. Still other embodiments may have portions or edges that may be partially sharpened or shaped as needed for their intended surgical procedure. While an actuation lever is shown in this embodiment, other embodiments may include an actuator such as a lever, sliding rod, knob, pulley, gear, solenoid, motor, or other actuator known to those skilled in the art. 
       FIGS. 2A-2C  are a series of exploded views illustrating the assembly of the distal end of the minimally invasive surgical device embodiment of  FIG. 1 .  FIG. 2A  illustrates the assembly steps of the distal tip housing  20  of the minimally invasive vessel harvesting device  10 . A blunt dissector  22  defining an upper dissector  28 , lower dissector  30 , and having an inner surface  32  also defines a dissector base  24  and a hub  26 . A gear assembly  34  defining a gear shaft  36  having an upper gear  38 , lower gear  40  and capstan  42  is placed inside the inner diameter of the hub  26  on the blunt dissector  22 . The upper gear  38  has several teeth  44  and recesses  45  interposed between the teeth  44 . Likewise, the gear  40  also has several teeth  46  and recesses  47  interposed between the teeth  46 . A pin  84  is inserted into hole  25  on the blunt dissector  22  and into a corresponding hole  37  on the gear assembly  34 . While a pin is used to assemble these components, other means of assembly may also be used, such as adhesion, welding, or utilizing a single component in another embodiment that defines the dissector and the gear assembly. Next, the blunt dissector  22  and gear assembly  34  are placed into a hole  54  on a distal end  48 D of an upper distal tip housing  48 . The upper distal tip housing  48  also defines an alignment guide  50 , a side wall  56 , and a tube portion  58  at a proximal end  48 P. The tube portion  58  further defines an internal channel  52 . 
       FIG. 2B  illustrates the continued assembly of the minimally invasive vessel harvesting device  10  of  FIG. 1 . A drive element, in this embodiment a barrel chain  60 , having several barrel  62  portions interposed between several tab  64  portions along a wall  66  of the barrel chain  60  is placed inside the upper distal tip housing  48  such that the wall  66  of the barrel chain  60  rides against the side wall of the upper distal tip housing  48  opposite side wall  56 , the barrels  62  are captured in the recesses  47  between the teeth  46  on the lower gear  40  and also in the recesses  45  between the teeth  44  on the upper gear  38  (although not visible in this view), around the gear assembly and against the side wall  56  of the upper distal tip housing  48 . It should be noted that the tabs  64  are sized and configured such that they will provide stiffness to the barrel chain  60  as well as maintain alignment and tracking of the barrel chain  60  in the capstan  42  portion, not visible here, of the gear assembly  34 . A drive coupler  68  having a drive element coupler  70  and a drive rod coupler  72  at the end of a drive rod slot  74  is coupled to the end of the barrel chain  60  by fitting the drive element coupler  70  of the drive coupler  68  over the terminating barrel  62  in the barrel chain  60 . A drive rod  76  having a ball end  78  at the distal end  76 D of the drive rod  76  is captured in the drive rod coupler  72  by placing the ball end  78  into the drive rod coupler  72  and guiding the drive rod  76  through the drive rod slot  74  on the drive coupler  68 . The drive rod  76  and the drive coupler  68  are freely movable within the channel  52  inside the tube portion  58  of the upper distal tip housing  48 . A lower distal tip housing  80  having a tube portion  82  at a proximal end  80 P is fixedly attached to the upper distal tip housing  48 , completing the assembly of the upper distal tip housing  48 .  FIG. 2C  illustrates another assembly step in the minimally invasive vessel harvesting device  10 . The distal tip housing tube  86  with the drive rod  76  protruding is inserted into a shaft opening  90  of a distal end  18 D of the shaft  18  on the minimally invasive vessel harvesting device  10 . This distal tip housing tube  86  is fixedly attached to the shaft  18  by welding, brazing or other methods known to those skilled in the art. Further assembly steps of the device including the handle, lever and other components is well known to those skilled in the arts of minimally invasive vessel harvesting devices. It should be noted that while a barrel chain drive is described in regard to the embodiment described herein, that other drive elements or drive mechanisms may also be used in other embodiments of the minimally invasive vessel harvesting device. The embodiment shown has a monolithic, or single piece barrel chain as the drive element. A drive element could include a chain or a belt, a coupler, a drive rod, or a combination thereof. Alternate drive attachments to the gear assembly including the capstan and gears shown herein may be used, for example, slotted shafts or spools, cylindrical bearings or bushings, or other rotatable shafts known to those skilled in the art. Any structural element suitable for extending from or attaching to the blunt dissector for the purpose of attaching a drive element to and rotating the blunt dissector would be a suitable drive attachment. Alternative drive elements to the barrel chain and drive coupler may also be used as drive elements in other embodiments of the minimally invasive vessel harvesting device described herein. Stiff belts, rods, wires, linked chains, or other linkages known in the art capable of pushing or pulling on a drive attachment coupled to a blunt dissector may be used as drive elements in alternate embodiments. 
       FIGS. 3A and 3B  are side partial cross-sectional and top partial cross-sectional views, respectively, illustrating a first operational state of the minimally invasive vessel harvesting device of  FIG. 1 .  FIG. 3A  illustrates the invasive vessel harvesting device  10  in a neutral position with respect to the position of the actuation lever  16  and the blunt dissector  22 . The actuation lever  16  is in a position partially away from the handle  14 , and the blunt dissector  22  is oriented in a position such that it is aligned with the shaft  18  of the minimally invasive vessel harvesting device  10 . The internal components of the actuation lever  16  are also visible in the cross-sectional view of  FIG. 3A . The actuation lever  16  is pivotably coupled about a pivot  92  and also defines a lever gear  94  with several lever gear teeth  96 . A drive gear  100  pivots about a pivot point  88 , and the drive gear  100  defines several teeth  101  and a drive gear coupler  102 . The teeth  101  on the drive gear  100  engage with the teeth  96  on the lever gear  94 . The drive rod  76  has a drive rod coupling ball  98  on its proximal end  76 P, which is held within the drive gear coupler  102 . 
       FIG. 3B  is a top cross-sectional view of the upper distal tip housing  48 , illustrating the position of the components within the upper distal tip housing  48 , particularly the blunt dissector  22  corresponding to the lever position shown in  FIG. 3A . It should be noted that in this position shown in  FIG. 3B , the blunt dissector  22  is oriented in such a fashion that the arcuate portion of the blunt dissector  22  is aligned with the shaft  18  of the minimally invasive vessel harvesting device  10 , at an angle of approximately 0 degrees in reference to the angle indicator shown in  FIG. 3B . 
       FIGS. 3C and 3D  are side partial cross-sectional and top partial cross-sectional views, respectively, illustrating a second operational state of the minimally invasive vessel harvesting device of  FIG. 1 .  FIG. 3C  illustrates the invasive vessel harvesting device  10  in a rotated position with respect to the position of the actuation lever  16  and the blunt dissector  22 . The actuation lever  16  is in a position squeezed in a direction  104  towards the handle  14 , and the blunt dissector  22  is oriented in a position such that it is rotated clockwise in reference to the shaft  18  of the minimally invasive vessel harvesting device  10 . When the lever  16  is squeezed towards the handle  14 , the lever gear  94  engages lever drive gear  100  and rotates the lever drive gear  100  in direction  106 . Since the lever drive gear  100  is coupled to the drive rod  76 , the drive rod  76  is pulled in direction  108 .  FIG. 3D  is a top cross-sectional view of the upper distal tip housing  48 , illustrating the position of the components within the upper distal tip housing  48 , particularly the blunt dissector  22  corresponding to the lever position shown in  FIG. 3C . As drive rod  76  is pulled in direction  108 , drive coupler  68  is also pulled in direction  108  as the ball end  78  of the drive rod  76  is coupled to the drive coupler  68 . The barrel chain  60  is also pulled in direction  108 , as the barrel chain  60  coupled to the drive element coupler  70  on the drive coupler  68 . Thus, the blunt dissector  22  is rotated in direction  110  as the barrel chain  60  engages with the teeth  46  on lower gear  40 , being at an angle of approximately 135 degrees in reference to the angle indicator shown in  FIG. 3D . 
       FIGS. 3E and 3F  are side partial cross-sectional and top partial cross-sectional views, respectively, illustrating a third operational state of the minimally invasive vessel harvesting device of  FIG. 1 .  FIG. 3E  illustrates the invasive vessel harvesting device  10  in another rotated position with respect to the position of the actuation lever  16  and the blunt dissector  22 . The actuation lever  16  is in an open moved in a direction  112  away from the handle  14 , and the blunt dissector  22  is oriented in a position such that it is rotated counterclockwise in reference to the shaft  18  of the minimally invasive vessel harvesting device  10 . When the lever  16  is moved away from the handle  14 , the lever gear  94  engages lever drive gear  100  and rotates the lever drive gear  100  in direction  114 . Since the lever drive gear  100  is coupled to the drive rod  76 , the drive rod  76  is pushed in direction  116 .  FIG. 3F  is a top cross-sectional view of the upper distal tip housing  48 , illustrating the position of the components within the upper distal tip housing  48 , particularly the blunt dissector  22  corresponding to the lever position shown in  FIG. 3E . As drive rod  76  is pushed in direction  116 , drive coupler  68  is also pushed in direction  116  as the ball end  78  of the drive rod  76  is coupled to the drive coupler  68 . The barrel chain  60  is also pushed in direction  116 , as the barrel chain  60  coupled to the drive element coupler  70  on the drive coupler  68 . The tabs  64  on the barrel chain  60 , as previously described, provide additional support and stiffness to the barrel chain  60  and allow the chain to be pushed. Thus, the blunt dissector  22  is rotated in direction  118  as the barrel chain  60  engages with the teeth  46  on lower gear  40 , at an angle of approximately −135 degrees in reference to the overlaid angle indicator shown in  FIG. 3F . The embodiment described herein has a blunt dissector  22  which is pivotable relative to the distal housing and is pivotable in a rotation range of about 270 degrees in reference to the overlaid angle indicator shown in  FIGS. 3B, 3D, and 3F . This rotation of the blunt dissector  22  is pivotable about a plane that is substantially parallel to the distal housing. Other embodiments including a rotatable dissector such as the one described herein may be configured to rotate over a full range of about 210 degrees, about 270 degrees or about 360 degrees. The rotation range of the blunt dissector  22  enables a precise control over the articulation and position of the blunt dissector during surgical procedures involving vessel harvesting. 
       FIGS. 4A-4C  illustrate alternate embodiments of drive mechanisms for embodiments of the minimally invasive surgical device of  FIG. 1 .  FIG. 4A  is a top view of a belt drive element  120  which is coupled to a drive shaft  122  similar to the capstan of the embodiment of a vessel harvesting device as shown in  FIGS. 1-3F . This drive shaft  122  has a capstan slot  124  into which the belt drive element  120  is fixedly attached. 
       FIG. 4B  is a top view of a segmented chain drive  126  which is coupled to a gear assembly drive shaft  123  similar to the capstan of the embodiment of a vessel harvesting device as shown in  FIGS. 1-3F . This segmented chain drive  126  has a gear assembly drive shaft  123  around which the segmented chain drive  126  is coupled. The segmented chain drive  126  is made of several links  128 . Each link  128  defines a clasp  13  having a recess  132 , a support tab  134 , and a peg  136 . Each link  128  is connected to another subsequent link  128  by connecting a tab  136  one link  128  to a recess  132  on the subsequent link  128 . 
       FIG. 4C  is a top view of another embodiment of a barrel chain  138  comprised of a single piece having several barrels  140  disposed upon a chain wall  142  and spaced such that they engage with and couple to with the gears on a gear assembly drive shaft  125 , similar to the capstan of the embodiment of a vessel harvesting device as shown in  FIGS. 1-3F . 
       FIGS. 5A-5H  illustrate alternate embodiments of dissectors for a minimally invasive surgical device.  FIG. 5A  is a side view of an alternate embodiment of a dissector for a minimally invasive vessel harvesting device.  FIG. 5A  shows a dissector  144  having a dissector base  146 , an upper dissector  148 , and a lower dissector  150 . The dissector  144  also defines an inner surface  152 . This dissector  144  has an arcuate, C-shaped profile with an opening on one side.  FIG. 5B  is a side view of an alternate embodiment of a dissector for a minimally invasive vessel harvesting device.  FIG. 5B  shows a dissector  154  having a dissector base  156 , an upper dissector  158 , and a lower dissector  160 . The dissector  144  also defines an inner surface  152 . This dissector  144  has an arcuate, C-shaped profile with an opening facing a slightly downward angle.  FIG. 5C  is a side view of an alternate embodiment of a dissector for a minimally invasive vessel harvesting device.  FIG. 5C  shows a dissector  164  having a dissector base  166 , an upper dissector  168 , and a lower dissector  170 . The dissector  164  also defines an inner surface  172 . This dissector  164  has an angular square-like profile with a side facing opening.  FIG. 5D  is a side view of an alternate embodiment of a dissector for a minimally invasive vessel harvesting device.  FIG. 5D  shows a dissector  174  having a dissector base  176 , an upper dissector  178 , a lower dissector  180 . The dissector  174  also defines an inner surface  182 . This dissector  174  has an angular, L-shaped profile.  FIG. 5E  is a side view of an alternate embodiment of a dissector for a minimally invasive vessel harvesting device.  FIG. 5E  shows a dissector  184  having a dissector base  186 , an upper dissector  188 , a lower dissector  190 . The dissector  184  also defines an inner surface  192 . This dissector  184  has an arcuate, C-shaped profile with a side facing opening.  FIG. 5F  is a side view of an alternate embodiment of a dissector for a minimally invasive vessel harvesting device.  FIG. 5F  shows a dissector  196  having a dissector base  198 , an upper dissector  200 , a lower dissector  202 . The dissector  196  also defines an inner surface  204 . This dissector  196  has an arcuate, C-shaped profile with a side facing opening.  FIG. 5G  is a side view of an alternate embodiment of a dissector for a minimally invasive vessel harvesting device.  FIG. 5G  shows a dissector  208  having a dissector base  210 , an upper dissector  212 , a lower dissector  214 . The dissector  208  also defines an inner surface  216 . This dissector  208  has an arcuate, C-shaped profile with a downward facing opening.  FIG. 5H  is a side view of an alternate embodiment of a dissector for a minimally invasive vessel harvesting device.  FIG. 5H  shows a dissector  226  having a dissector base  222 , an upper dissector  224 , a lower dissector  220 . The dissector  224  also defines an inner surface  218 . This dissector  224  has an arcuate, half C-shaped profile. Alternate embodiments of dissectors may have shapes such as L-shaped, corkscrew, or have sharper angles than embodiments directly illustrate herein. The inner surface of some of the alternate embodiments of the dissectors described herein may have smooth, textured, or conformable surfaces. Alternate embodiments of dissectors may be composed of materials such as plastic, metal, ceramic, composites, or combinations thereof. 
       FIG. 6  is a perspective view of another embodiment of a minimally invasive surgical device for vessel harvesting  228 . The minimally invasive vessel harvesting device  228  has a housing  230  which extends down to form a handle  232 . The device also has an actuation lever  234  which operates in a similar fashion as previous embodiments described herein. The minimally invasive vessel harvesting device  228  also has a shaft  242  which is coupled to the housing  230  by a rotational adapter which is not completely visible in this view, but is known to those skilled in the art. An indicator fin  236  of the rotational adapter can be seen in this view, however. The minimally invasive vessel harvesting device  228  has a distal tip housing  254  which is pivotably coupled to a distal shaft portion  244  by a second articulation joint  248 . The distal tip housing has a blunt dissector  252  similar to those described previously herein. The distal shaft portion  244  is pivotably coupled to the shaft  242  by a first articulation joint  246 . The first articulation joint  246  is operationally coupled to a first articulation knob  238  such that rotation of the first articulation knob  238  causes the first articulation joint  246  to articulate the distal shaft portion  244  in a first plane  250 . The second articulation joint  248  is operationally coupled to a second articulation knob  240  such that rotation of the second articulation knob  240  causes the second articulation joint to articulate the distal tip housing  254  in a second plane  256 . In this example, the first plane  250  is substantially perpendicular to the second plane  256 . In other embodiments having two articulation joints, the two articulation planes may not be substantially parallel. Other embodiments may have more or fewer, including none, articulation joints. The articulation joints in other embodiments may be capable of movement in more than one plane. Embodiments of rotation adapters and minimally invasive surgical devices are known to those skilled in the art. 
       FIG. 7  is a perspective view of a further embodiment of a minimally invasive surgical device for vessel harvesting  260 . The minimally invasive vessel harvesting device  260  has a housing  262  which forms an ergonomic handle  264 . The device also has a channel  266  which is configured to provide a path for a sliding member  270  to slide longitudinally along the device  260  from its distal end  260 D to its proximal end  260 P. The channel  266  also defines several positioning recesses  268  which correspond to mating features on the sliding member  270 . This aspect of the design provides a means to slide the sliding member  270  along the channel  260 , while locking the position of the sliding member  270  if desired. The minimally invasive vessel harvesting device  260  also has a shaft  274  which is coupled to the housing  262 . The shaft  274  extends towards the distal end  260 D of the minimally invasive vessel harvesting device  260  and has a secondary shaft  276  coupled to the shaft  274 . Coupled to the secondary shaft  276  is a distal tip  278  which defines a u-shaped or protuberant, arcuate finger  280  extending in an arcuate fashion. The arcuate curvature of the finger  280  is formed in a direction substantially perpendicular to the distal tip  278  and perpendicular to the shaft  274  and secondary shaft  276  and may be considered as and used as a blunt dissector. While the arcuate finger  280  does not close at both ends in contact with the distal tip  278 , a gliding member  282  provides such a closure. The gliding member  282  is coupled to the sliding member  270  and configured such that when the sliding member  270  is moved towards the proximal end  260 P, the gliding member  282  also moves towards the proximal end  260 P of the minimally invasive vessel harvesting device  260 . When the gliding member  282  moves in a direction towards the proximal end  260 P of the minimally invasive vessel harvesting device  260 , the arcuate finger  280  is open. This open position allows for the minimally invasive vessel harvesting device  260  to be placed around a vessel such as an IMA to place the arcuate finger  280  around the vessel during a harvesting or takedown procedure. When the gliding member  282  moves in a direction towards the distal end  260 D of the minimally invasive vessel harvesting device  260 , the arcuate finger  280  is in a position that in combination with the position of the arcuate finger  280  forms a closed loop. This closed loop position allows for the operator of the minimally invasive vessel harvesting device  260  to hold or secure a vessel such as an IMA in place within the closed loop formed by the gliding member  282  and the arcuate finger  280  during a harvesting or takedown procedure. In other embodiments the loop formed by the gliding member  282  and the arcuate finger  280  may be substantially parallel to the shaft  274  of the minimally invasive vessel harvesting device  260 , or at a position somewhere between substantially parallel and substantially perpendicular. Other embodiments may not form an arcuate loop and may form closures or loops of differing shapes. 
       FIG. 8  is perspective view of another embodiment of a minimally invasive surgical device for vessel harvesting  286 . The minimally invasive vessel harvesting device  286  has a housing  288  which forms an ergonomic handle  290 . The minimally invasive vessel harvesting device  286  also has a shaft  292  which is coupled to the  288 . The shaft  292  extends towards the distal end  286 D of the minimally invasive vessel harvesting device  286 . Coupled to the shaft  292  are several arcuate shaped blunt dissectors or omega-shaped fingers  296 ,  302 ,  308 . These are referred to as omega-shaped due to their similarity to the Greek letter omega. They may also be referred to as c-shaped or u-shaped. The arcuate curvature of the fingers  296 ,  302 ,  308  are formed in a direction substantially perpendicular to the shaft. A first omega-shaped finger  296  is coupled to the shaft  292  by a first tubular mount  294  and defines an opening  298 . A second omega-shaped finger  302  is coupled to the shaft  292  by a tubular mount  300  and defines an opening  304 . A third omega-shaped finger  308  is coupled to the shaft  292  by a tubular mount  306  and defines an opening  310 . The openings  298 ,  304 ,  310  formed by each of the omega-shaped fingers  296 ,  302 ,  308  allows for the minimally invasive vessel harvesting device  286  to be placed around a vessel such as an IMA in one or more locations to place one or more of the omega-shaped fingers  296 ,  302 ,  308  around the vessel during a harvesting or takedown procedure to temporarily hold or secure the vessel in a desired placement or position. In other embodiments the opening formed by the fingers  296 ,  302 ,  308  may be substantially parallel to the shaft  292  of the minimally invasive vessel harvesting device  286 , or at a position somewhere between substantially parallel and substantially perpendicular. Other embodiments of fingers may not form an arcuate loop and may form closures or loops of differing shapes. 
       FIG. 9  is a perspective view of a further embodiment of a minimally invasive surgical device for vessel harvesting  312 . The minimally invasive vessel harvesting device  312  has a housing  314  at a proximal end  312 P, the housing forming an ergonomic handle  316 . The device  312  also has an articulation lever  318  disposed within the housing  314  and a rotation adaptor knob  320 . The rotation adaptor knob  320  can be rotated around a longitudinal axis of an attached shaft  322  to enable rotatable positioning of the shaft  322  and therefore a distal end  312 D of the device  312 . The hollow shaft  322  is mounted onto the rotation adaptor knob  320  and contains a rigid rod or drive wire which is not visible here but will be described later in more detail. Along the shaft  322 , closer to the housing  314 , is a first plurality of horizontal articulation joints  324  each composed of several slits  324 S. Further towards the distal end  312 D of the device  312 , also located along the shaft  322 , is a second plurality of vertical articulation joints  326  each composed of several slits  326 S. The first plurality of articulation joints  324  articulate in a plane substantially perpendicular to or substantially horizontal in relation to a plane bisecting the housing  314  or in line with the lever  318 . The second plurality of articulation joints  326  articulate in a plane substantially parallel to or substantially vertical in relation to a plane bisecting the housing  314 . These articulation joints  324 ,  326  are constructed of slits  324 S,  326 S in the desired direction of articulation. It should be noted that upon rotation of the rotation adaptor knob  320  this aforementioned relationship of the direction of articulation between the shaft  322  and the directions of articulation become offset by the amount of rotation. In the case of the embodiment shown in  FIG. 9 , each partial rotation of the rotation adaptor knob  320  rotates the shaft  322  sixty degrees about a longitudinal axis defined by the shaft  322 , although alternate embodiments may have different extents of partial rotation. Alternate embodiments of an articulating shaft  322  may include varying numbers of slits, for example, from about 1 to about 10, from about 3 to about 8, or from about 5 to about 7. The slits  324 S,  326 S are defined by partial circumferential segmentation of the outer surface of the hollow rigid shaft  322 . While the articulation feature in this embodiment consists of multiple slits for each joint, the articulation feature in alternate embodiments may also include other articulating joint constructions configured to be similarly positioned, such as hinges, flexible shaft materials, and other types of articulating joint construction known to those skilled in the art, and will also be configured such that the shaft  322  can be formed into a desired shape or angle of approach for the surgical procedure, and will remain in the set configuration until intentionally moved to a different shape or angle of the shaft  322 . While these articulation joints  324 ,  326  move and are configured to be positioned in the aforementioned planes, alternate arrangements of articulation joints may be used in alternate device embodiments. For example, horizontal articulation joints may be located closer to the distal tip  328  while vertical articulation joints may be located closer to the housing  314 , vertical and horizontal articulation joints may alternate along the shaft, or varying numbers of each may be present in alternate device embodiments. Further towards the distal end  312 D of the device  312  is a distal tip  328  fixedly mounted onto the shaft  322 . The distal tip  328  includes an arcuate finger  330  and a slidably engaged gliding member  332  which reversibly form a channel or opening  334  defined by the combination of the gliding member  332  and the arcuate finger  330  in the position shown in  FIG. 9 . The enclosed channel or opening  334  is configured to retain a vessel, artery, or other anatomical feature within the channel or opening  334 . The vessel, artery, or other anatomical feature can be released by actuating the lever  318 . As the lever  318  of the device  312  is squeezed towards the handle  316 , the gliding member  332  moves along a cam path  336  defined by the distal tip  328  to open and allow entry or passage of a vessel or other anatomical feature into the channel or opening  334  defined by the distal tip  328 . Further details of this movement are detailed in regard to  FIGS. 10A and 10B . 
       FIGS. 10A-10B  are perspective views of a distal end of the minimally invasive surgical device of  FIG. 9 , illustrating a closed and opened position, respectively.  FIG. 10A  illustrates the arrangement of the distal tip  328  when the lever  318  of the device  312  is in the unsqueezed position, with lever  318  positioned away from the handle  316 . The drive wire  342  is coupled to the gliding member  332  and is fully extended towards the distal end  312 D of the device  312 . This arrangement maintains the gliding opening  334  at the distal tip  328  of the device  312 , with the gliding member  332  and the arcuate finger  330  completing a full closure around the channel or opening  334 . In this configuration, a vessel can be entrained within the opening  334  for holding or other desired surgical manipulation, for example, during a vessel harvesting minimally invasive surgical procedure. When the lever  318  is squeezed towards the handle  316  of the device  312 , the drive wire  342  and also the connected gliding member  332  are caused to slide or move in direction  338 , towards the proximal end  312 P of the device  312 . 
       FIG. 10B  illustrates the position of the features and elements of the distal tip  328  of the device  312  once the handle  316  is squeezed towards the handle  316 . As the drive wire  342  moves in direction  338 , the gliding member  332  moves along with the drive wire  342  along the cam path  336  defined by the distal tip  328 . The cam path  336  is configured such that the gliding member  332  rotates away from the distal tip  328  in direction  340  as the inner surface of the gliding member  332  interferes with the defined path of the cam path  336 . This movement in direction  338  and substantially simultaneous rotation in direction  340  allows for additional clearance to open the opening  334  for a vessel or other anatomical feature to be placed within the opening  334  on the distal tip  328  of the device  312 . When the desired anatomical feature is placed into the opening  334 , the lever  318  can be released by the user of the device  312  and position of the distal tip  328  returns to the position illustrated in  FIG. 10A , effectively trapping or capturing the anatomical feature securely in the opening  334  of the distal tip  328 . 
       FIG. 11  is a perspective view of another embodiment of a minimally invasive surgical device for vessel harvesting  344 . The minimally invasive vessel harvesting device  344  has a housing  346  at a proximal end  344 P, the housing forming an ergonomic handle  348 . The device  344  also has an articulation lever  350  disposed within the housing  346  and a rotation adaptor knob  352 . The rotation adaptor knob  352  can be rotated around a longitudinal axis of an attached shaft  354  to enable rotatable positioning of the shaft  354  and therefore a distal end  344 D of the device  344 . The hollow shaft  354  is mounted onto the rotation adaptor knob  352  and contains a drive wire which is not visible here but will be described later in more detail. Along the shaft  354 , closer to the housing  346 , is a first plurality of horizontal articulation joints  356  each composed of several slits  358 . Further towards the distal end  344 D of the device  344 , also located along the shaft  354 , is a second plurality of vertical articulation joints  360  each composed of several slits  362 . The first plurality of articulation joints  356  articulate in a plane substantially perpendicular to or substantially horizontal in relation to a plane bisecting the housing  346  or in line with the lever  350 . The second plurality of articulation joints  360  articulate in a plane substantially parallel to or substantially vertical in relation to a plane bisecting the housing  346 . These articulation joints  356 ,  360  are constructed of slits  358 ,  362  in the desired direction of articulation. It should be noted that upon rotation of the rotation adaptor knob  352  this aforementioned relationship of the direction of articulation between the shaft  354  and the directions of articulation become offset by the amount of rotation. In the case of the embodiment shown in  FIG. 11 , each partial rotation of the rotation adaptor knob  352  rotates the shaft  354  sixty degrees about a longitudinal axis defined by the shaft  354 , although alternate embodiments may have different extents of partial rotation. Alternate embodiments of an articulating shaft  354  may include varying numbers of slits, for example, from about 1 to about 10, from about 3 to about 8, or from about 5 to about 7. The slits  358 ,  362  are defined by partial circumferential segmentation of the outer surface of the hollow rigid shaft  354 . These slits may be formed by laser cutting, machining, or other means known to those skilled in the art. While the articulation feature in this embodiment consists of multiple slits for each joint, the articulation feature in alternate embodiments may also include other articulating joint constructions configured to be similarly positioned, such as hinges, flexible shaft materials, and other types of articulating joint construction known to those skilled in the art, and will also be configured such that the shaft  354  can be formed into a desired shape or angle of approach for the surgical procedure, and will remain in the set configuration until intentionally moved to a different shape or angle of the shaft  354 . While these articulation joints  356 ,  360  move and are configured to be positioned in the aforementioned planes, alternate arrangements of articulation joints may be used in alternate device embodiments. For example, horizontal articulation joints may be located closer to a distal housing or distal tip  364  while vertical articulation joints may be located closer to the housing  346 , vertical and horizontal articulation joints may alternate along the shaft, or varying numbers of each may be present in alternate device embodiments. Further towards the distal end  344 D of the device  344  is a distal tip  364  fixedly mounted onto the shaft  354 . The distal tip  364  includes an arcuate first blunt dissector  366  and an arcuate second blunt dissector  368  that are in an open position. The first blunt dissector may also be referred to as an arcuate finger, and the second blunt dissector  368  may also be referred to as a fixed member or a gliding member, due to a gliding movement of the first cam portion  382  throughout a cam path. When open, as illustrated in  FIG. 11 , the distal tip  364  is configured to receive a vessel, artery, or other anatomical feature within the distal tip  364  when the distal tip  364  is closed. The vessel, artery, or other anatomical feature can be retained and releasably held by actuating the lever  350  and placing the first blunt dissector  366  and the second blunt dissector  368  into a closed position. Further details of this operational movement are detailed in regard to  FIGS. 13A-13B and 14A and 14B . 
       FIG. 12  is an exploded view of a distal end of the minimally invasive surgical device of  FIG. 11 . The hollow shaft  354  is shown, having a tip  370  fixedly attached to the hollow shaft  354 , further defining a head  372  and a keyway  374 . A flat tip key  376  having a drive coupler  378  and an actuator coupler  386  is inserted into the keyway  374  on the tip  370 . The flat tip key  376  is coupled to the drive wire, which is not shown in this view. An actuator pin  380 , further defining a first cam portion  382  and a second cam portion  384  is attached to the actuator coupler  386  on the flat tip key  376 . Next, a first guide tip portion body  388  which defines a first cam path  390 , a channel  392 , and the first blunt dissector  366  is placed over the tip  370  on the hollow shaft  354 . A second guide tip portion body  394 , which defines an inner cam path  396 , and the second blunt dissector  368  having a is then placed inside the first guide tip portion body  388 , completing the distal tip  364  assembly. 
       FIGS. 13A and 13B  are perspective views focused on an assembled distal end of the minimally invasive surgical device of  FIG. 11  in open and closed positions, respectively. When the minimally invasive device is at rest, the relative positions of second blunt dissector  368  and first blunt dissector  366  are in an open position, and the first cam portion  382  is located closer to the hollow shaft  354  within the first cam path  390  on the first guide tip portion body  388 . There may be a corresponding cam path on the opposite side of the first guide tip portion body  388  which is not shown in this view. The corresponding cam path may just be a straight path, rather than the curved path of the first cam path  390 . The second blunt dissector  368  has a guiding feature  398  that seats within a corresponding recess (not shown) on the first blunt dissector  366 .  FIG. 13B  shows the first blunt dissector  366  and second blunt dissector  368  in a closed position. Once the actuation lever is squeezed, the drive wire pushed distally, and the first cam portion  382  engaged in a distal direction away from the shaft within the first cam path  390 , the first blunt dissector  366  and second blunt dissector  368  are in a closed position. This operating function will be further discussed in regard to  FIGS. 14A and 14B . 
       FIGS. 14A and 14B  are a side partial cross-sectional view and distal end view, respectively, of the minimally invasive surgical device of  FIG. 11  in an open position. Within the housing  346  of the device  344 , a spring  402  is shown providing a bias on the actuation lever  350  while the device  344  is in an open position or a position in which the actuation lever  350  has not been actuated. Also visible are the drive wire  400  coupled to a ball end  406  captured in a lever coupler  404  within the actuation lever  350 .  FIG. 14B  is a front-end view showing the position of the first blunt dissector  366 , second blunt dissector  368 , and guiding feature  398  while the device  344  is in the open position. In this position, the device  344  is configured to receive a vessel, artery, or other anatomical feature within the opposing pincers, or first blunt dissector  366  and second blunt dissector  368 . 
       FIGS. 15A and 15B  are a side partial cross-sectional view and front-end view, respectively, of the minimally invasive surgical device of  FIG. 11  in a closed position. As the actuation lever  350  of the device  344  is squeezed or actuated towards the handle in direction  408 , the drive wire  400  is moved in a direction  410  towards the distal end of the device  344 . As previously described in regard to  FIGS. 13A and 13B , as the drive wire  400  and first cam portion  382  are coupled, the movable second blunt dissector  368  is pushed closed relative to the fixed first blunt dissector  366  along first cam path  390 , where in the closed position, the device  344  may be used to hold onto and gently grasp a vessel, artery, or other anatomical feature within the closed structure defined by the first blunt dissector  366  and second blunt dissector  368 . 
       FIG. 16  is an enlarged side view of a portion of the shaft of the minimally invasive surgical device of  FIG. 11 .  FIG. 16  shows an enlarged side view highlighting a hollow shaft  414  having a first set of slits  412  which includes a first plurality of slits  416  and a second plurality of slits  418 . The hollow rod or shaft  414  has a length and an outer circumference. The first set of slits includes a first plurality of slits across the outer circumference dissecting an apex of the hollow rod and a second plurality of slits oriented 180 degrees around the outer circumference of the hollow rod relative to the first plurality of slits. Each of the slits illustrated in  FIG. 16  are made of a cross-sectional compound shape incorporating a rectangular portion and a circular portion. The rectangular portion is in communication with the outer circumference of the hollow rod. Other embodiments may incorporate slits having alternate compound shapes or alternate orientations of respective portions of compound shapes, such as triangles, squares, and other multi-sided polygons to form a variety of compound shapes. 
     Several parameters are notated in  FIG. 16 , designating important dimensional considerations relative to the slit geometry and arrangement. Diameter, d, of the circular portion of the slit, and cross-sectional height, h, of each slit is notated. As several heights are shown, h 1 , h 2 , h 3 , h 4 , they are separately designated. The heights in each of the first plurality of slits  416  and a second plurality of slits  418  illustrated in  FIG. 16  show an arched or parabolic arrangement as formed by the plurality of adjacent slits. Other embodiments may have different shaped arches or arcs or may be of equivalent heights with respect to adjacent slits. The width, w, of the rectangular portion of each slit is designated, as is the spacing, s, between each slit. Lastly, the web distance, We, the distance between the circular portion or inner boundary of each of the first plurality of slits  416  and the inner boundary or circular portion of each of the second plurality of slits is indicated in  FIG. 16 . The diameter, d, of the circular portion is believed to influence the stress induced on the hollow shaft when bending. The circular portion is considered to reduce stress concentrations during multiple bending operations while articulating the shaft multiple times during the use of an instrument. Larger diameter circles may reduce the stresses induced while bending as compared to smaller diameter circles. The cross-sectional height—h 1 , h 2 , h 3 , h 4 —of the slit is inversely proportional to the web distance, We, and the balance between height and web distance may provide a tradeoff in the operation and performance of the instrument shaft between bendability and yield strength. This particular arrangement provides an instrument shaft configured to yield under bending stresses without breaking. When We is larger more stress can be accommodated by the instrument shaft under bending stress, and when We is smaller, less stress can be accommodated by the instrument shaft under bending stress. Height, h, width, w, and spacing between slits, s, influence the bend angle and bending radius of the portion of the hollow instrument shaft that includes a set of slits. Reduced dimensions in h, w, and s will provide a tighter bend radius, and vice versa. It should be noted that regardless of the relative dimensions and arrangements of each of the aforementioned parameters illustrated in  FIG. 16 , that each of the slits may have differing values of each of the aforementioned parameters in alternate embodiments of an articulatable instrument shaft. This combination of parameters and features as described can be combined to provide an articulatable instrument shaft that has rigidity, malleability, and robustness that can be articulate and bent, hold its shape, and be repeatedly manipulated during the course of a minimally invasive surgical procedure. As shown in  FIG. 11 , for example, an instrument shaft may have multiple sets of slits having similar features as described previously, such as a second set of slits, or a third or fourth set of slits, or more. These multiple sets of slits may be all oriented similarly, or as in the example from  FIG. 11 , the multiple sets of slits are perpendicular to one another, for example, a second set of slits is oriented 90 degrees around the outer circumference of the hollow rod relative to the first plurality of slits. Additionally, alternate embodiments may have only one set of slits or may be oriented 180 degrees apart or of varying angles depending on application considerations. Furthermore, slits may have alternate shapes—such as triangular, circular, polygonal—alternate compound shapes—such as dog bone, mushroom, or hot dog-shaped—and alternate dimensions as compared to those characterized and defined herein. Overall shaft diameter also plays a role and interacts with each of the features defined previously, and presumably would have to be modified or scaled proportionally for differing shaft diameters. 
     The surgical device embodiments for vessel harvesting disclosed herein, and their equivalents, are useful, as a non-limiting example, for use in harvesting either the left internal thoracic artery (LITA) or the right internal thoracic artery (RITA), especially, although not exclusively, through a minimally invasive subxiphoid incision. When operating it is also desirable for the surgeon to have an apparatus for estimating how far the dissected portion of the vessel will reach and/or how much farther the vessel needs to be dissected in order to reach its desired anastomosis point. A harvested ITA graft of an appropriate length can be perfectly anastomosed to the usual site on the left anterior descending (LAD) artery, or onto the right coronary artery (RCA). 
       FIG. 17  illustrates one embodiment of a flexible length indicator  420  for use with a minimally invasive surgical device for vessel harvesting. The flexible length indicator  420  has a tether  422  which is configured to be coupled to the distal end of a surgical device for vessel harvesting. Although the tether  422  is a closed ring in this embodiment, other embodiments of a suitable tether could be partial rings, split rings, or even have different shapes. The flexible length indicator  420  also has flexible shaft  423  coupled to the tether  422 . Depending on the embodiment, the flexible shaft  423  may be flexible along its entire length or only during one or more sections of its length. The flexible length indicator  420  may be made from a variety of materials, and although it is illustrated in a linear orientation in  FIG. 17 , the flexible indicator is able to be flexed into a variety of orientations. This embodiment of a flexible length indicator  420  also has one or more reference tabs  424  extending from the flexible shaft  423 . The one or more reference tabs  424  may be used to estimate harvested vessel length for comparison with how far the harvested vessel is able to reach or needs to reach towards a desired anastomosis site. In the embodiment of  FIG. 17 , the reference tabs  424  have individually identifiable markers  426  on them. In some embodiments, these markers  426  may simply be for unique reference so that a particular reference tab  424  may be repeatedly identified. In other embodiments, the markets  426  may correspond to a distance on a known measurement scale. Other embodiments may not have markers. The reference tabs  424  also provide a convenient location for the surgeon to grasp and position the flexible length indicator  420 . 
       FIG. 18  illustrates the flexible length indicator  420  of  FIG. 17  attached to the distal end of an embodiment of a minimally invasive surgical device  428  for vessel harvesting. In this example, the tether  422  of the flexible length indicator  420  has been installed onto one of the dissectors  430  of the surgical device  428 . The surgical device  428  in this view has two blunt dissectors  430  and  432 . The flexible length indicator  420  could be installed onto either dissector  430 ,  432 . 
       FIG. 19  schematically illustrates the flexible length indicator  420  of  FIG. 17  being used to estimate a desired harvest vessel length while the embodied minimally invasive surgical device  428  for vessel harvesting to which it is attached is in use for vessel  434  dissection. In this view, the target vessel  434  has been dissected up to a tissue connection point  436 . With the dissectors  430  positioned around the vessel  434  at the tissue connection point  436 , the flexible length indicator  420  can be guided towards the patient&#39;s heart  438  on a desired path until it is positioned over the target anastomosis site  440 . The surgeon may then use the corresponding marker  424 C to estimate the necessary length of the vessel from the current tissue connection point  436  needed to reach the target anastomosis site  440 . The flexible length indicator  420  may then be repositioned near the harvested vessel  434  to see if enough vessel  434  has been harvested. If a suitable length has been harvested, the surgeon can stop the dissection without freeing unnecessary length of vessel from the native tissue. The surgeon may also determine that more of the vessel needs to be harvested. By using the flexible length indicator rather than the harvested vessel to judge distance, unnecessary manipulation of the target vessel with grasping instruments is avoided. 
     Various advantages of a device for vessel harvesting have been discussed above. Additionally, minimally invasive ITA harvesting procedure involving sub-xiphoid access may also enable superior cosmetic results, should be much more painless and have shorter recovery times for the patient, and the arterial grafting can be accomplished on the beating heart. 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. As just one example, although the end effectors in the discussed examples were often focused on the use of a scope, such systems could be used to position other types of surgical equipment. 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. The drawings included herein are not necessarily drawn to scale. 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.