Abstract:
A peelable sheath is used to provide an atraumatic cover for an elongate medical device positionable through an incision. The peelable sheath includes a flexible tube, a pair of tabs on a proximal portion of the flexible tube, and a collar on a proximal portion of the flexible tube. The tabs extend laterally through at least one sidewall opening in the collar. The flexible tube is slidably disposed in a lumen of the collar. In use, the sheath is positioned covering at least a distal portion of the elongate medical device, and the elongate medical device is inserted into an incision or other opening in a patient. The sheath is withdrawn from the elongated medical device by pulling the tabs outwardly relative to the longitudinal axis of the flexible tube, causing at least a proximal portion of the flexible tube to split longitudinally into at least two longitudinal sections. The longitudinal sections move proximally through the at least one sidewall opening as the tabs are pulled.

Description:
RELATED APPLICATIONS 
       [0001]    This application claims the benefit of U.S. application Ser. No. 61/144,926, filed Jan. 15, 2009. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates generally to the field of sheaths used to facilitate passage of other medical instrument into body cavities or vessels. 
       BACKGROUND 
       [0003]    In many percutaneous medical procedures tubular sheaths are used as passageways providing access for other medical devices into body cavities or vessels. For example, vascular sheaths are used to give access into the vasculature for catheters, cardiovascular leads, or other therapeutic or diagnostic devices. In some such procedures, the sheath is passed into a blood vessel and the catheter or other device is inserted through the lumen of the sheath into the body. The sheath is next removed from the vessel, leaving the catheter or other device remaining in the vessel. In some cases where the catheter/lead etc has a large hub or connector at its proximal end, the sheath must be longitudinally split or peeled apart to allow it to be removed from the catheter. 
         [0004]    In conventional laparoscopic procedures, multiple small incisions or ports are formed through the skin and underlying muscle and peritoneal tissue to provide access to the peritoneal cavity for the various instruments and scopes needed to complete the procedure. Trocar sleeves or sheaths are positioned within the incisions, and the instruments are passed through these sleeves into the cavity. These sleeves or sheaths remain in the incision for the duration of the procedure and are not peeled away from the instruments passed through them. 
         [0005]    Applicant&#39;s co-pending U.S. application Ser. No. 12/649307, filed Dec. 29, 2009, Attorney Docket No. TRX-1820, ACTIVE INSTRUMENT PORT SYSTEM FOR MINIMALLY-INVASIVE SURGICAL PROCEDURES, which is incorporated herein by reference, describes an active port system used to give multi-instrument access into the abdominal cavity. The system disclosed in the prior application includes an insertion tube through which a plurality of access tubes extend. At least two of the access tubes extend from the distal end of the insertion tube. Link arms coupled to the distal portions of these access tubes are pivotable to change the lateral spacing of the access tubes. In use, the insertion tube is introduced through an incision in the umbilicus or another area of a body wall such as the abdominal wall. Instruments are passed through the plurality of access tubes and used to gain access to an operative site within the body cavity. It is desirable to minimize trauma to surrounding tissue as the distal end of the system (e.g. the distal portions of the access tubes and link arms the insertion tube) is inserted into the abdominal cavity. The present application discloses a sheath suitable for this purpose. 
         [0006]    As will be appreciated from the discussion that follows, the disclosed sheath is equally suitable for use other types of access systems, including but not limited to more conventional laparoscopic trocar systems, systems for natural orifice surgical access, and systems providing percutaneous intravascular access. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]      FIG. 1  is a perspective view of a first embodiment of a sheath system; 
           [0008]      FIG. 2  is an exploded view of the system of  FIG. 1 ; 
           [0009]      FIG. 3A  is a perspective view of the funnel of the sheath system of  FIG. 1 ; 
           [0010]      FIG. 3B  is a side elevation view of the funnel of  FIG. 3A ; 
           [0011]      FIG. 4  is a perspective view of the sheath system of  FIG. 1  after peeling; 
           [0012]      FIG. 5A  a surgical access system which can be incorporate the sheath system of  FIG. 1 ; 
           [0013]      FIG. 5B  illustrates positioning of the sheath system of  FIG. 1  with the surgical access system of  FIG. 5A ; 
           [0014]      FIG. 6  is similar to  FIG. 5 , but shows the tip removed from the sheath and the sheath having been peeled; 
           [0015]      FIG. 7  is similar to  FIG. 6 , but illustrates advancement of the peeled sheath towards excised tissue to be withdrawn from the body; 
           [0016]      FIG. 8  is a perspective view of a second embodiment of a sheath system; 
           [0017]      FIG. 9  is an exploded view of the sheath system of  FIG. 8 . 
       
    
    
     DETAILED DESCRIPTION 
       [0018]      FIGS. 1 and 2  illustrate a first embodiment of a peelable sheath system  100 . In general, the system includes a funnel  10 , a sheath  12  coupled to the funnel, a tip  14  positioned on the distal end of the sheath  12 , and a tether  16  coupled to the tip  14 . 
         [0019]    Referring to  FIG. 3A , funnel  10  is a tubular element having a proximal opening  18  and a distal opening  20 , with a lumen  22  extending between the proximal and distal openings.  FIG. 3B  best shows that in the illustrated embodiment, the funnel  10  has a generally cylindrical distal section  24 , and a proximal section  26  that tapers inwardly from the proximal opening  18  to a cylindrical base  30 . The base  30  has a diameter that is smaller than the diameter of the distal section  24 . 
         [0020]    A pair of slots  32  are formed in the wall of the funnel  10  between the base  30  and the distal section  24 . The entrance to each slot  32  has a radiused lower edge  34  and a beveled upper edge  36 . The slots  32  extend into the lumen  22  of the funnel  10 . 
         [0021]    Referring to  FIG. 2 , the sheath  12  is a tubular sleeve made of PTFE or other suitable material. A pair of finger grips  38  extend angularly from the proximal end of the sheath  12 . Each finger grip  38  has an opening  39  through which a user can thread his/her finger to grasp the finger grip  38 . 
         [0022]    A pair of longitudinal split lines  40  (one is visible) are positioned opposite one another along the body of the sheath and divide the sheath into longitudinal body sections  41 . The split lines  40  can extend the full length of the sheath, or they may terminate proximal to the distal end of the sheath. Split lines  38  are formed using any process that will make the split lines  40  weaker than the surrounding material, so that the sheath will preferentially split along the split lines  40  when a user pulls the finger grips  38  away from one another. Suitable processes for forming the split lines  40  include etching or scoring of the sheath material, or manufacturing the split lines  40  using a material less resistant to tearing than the surrounding material. 
         [0023]    The tip  14  is a distally tapered element formed of polymeric or other material. The tether  16  is attached to the tip. In one embodiment, the tether  16  extends through openings  44  formed in the tip as shown. The tip  14  is coupled to the distal end of sheath  12 , and is removed from the sheath when a user pulls on the tether  16 . 
         [0024]    Various arrangements may be used to couple the tip  14  to the sheath  12 . In one embodiment, the proximal end of the tip has an opening  42  that is press fit over the distal end of the sheath. Alternatively, a proximal portion of the tip may be inserted into the lumen of the sheath. In either case, friction or light adhesives may be used to retain the tip on the sheath until it is actively removed using the tether. 
         [0025]    As shown in  FIG. 1 , the sheath  12  and funnel  10  are assembled such that the proximal portion of the sheath  12  is positioned within the lumen  22  of the funnel  10 . The finger grips  38  extend through the slots  32  in the funnel  10 . When a user engages the finger grips  38  and pulls them laterally away from the longitudinal axis of the sheath, the sheath separates along the split lines  40 , allowing the user to pull the separated longitudinal body sections  41  through the slots  32  in the funnel  10  as shown in  FIG. 4 . By pulling the proximal portions of the body sections  41  through the slots  32 , the user retracts the distal end of the sheath proximally. If desired, the user can split the sheath along its entire length and then fully withdraw the longitudinal body sections  41  from the funnel  10 . 
         [0026]    Use of the system  100  will next be described with reference to an access system  200  of the type disclosed in Applicant&#39;s U.S. Provisional Application No. 61/141088, filed Dec. 28, 2008 (Attachment A hereto). Referring to  FIG. 5A , access system  200  includes an insertion tube  210  through which a plurality of access tubes  212 ,  214  extend. In use, the insertion tube extends through an incision in the umbilicus or another area of a body wall such as the abdominal wall. Instruments are passed through the plurality of access tubes and used to gain access to an operative site within the body cavity. The plurality of access tubes includes a pair of flexible tubes  212  having distal ends that may be articulated using proximal actuators  220 . A deployment system including link arms  218  is positioned to move the flexible tubes  212  between a streamlined orientation (similar to the position shown in  FIG. 7 ) for insertion into a body cavity and the spaced apart position shown in  FIG. 5A . The system components are supported by a frame  222  and include a coupling  224  that mounts the frame to a fixture within the operating room. 
         [0027]    Referring to  FIG. 5B , when the sheath system  100  is used in conjunction with the access system  200 , the funnel  10  is disposed around a proximal portion of the insertion tube  210 , and the sheath  12  covers at least a portion of the insertion tube, as well as the flexible tubes  212  and link arms  218  (not visible in  FIG. 5B ). The tip  14  is coupled to the distal end of the sheath  12 , and the tether  16  extends proximally. To accommodate the sheath  12  and tip  14 , the flexible tubes  212  and link arms  218  are positioned in the streamlined orientation. 
         [0028]    The distal end of the access system  200 , with the sheath system  100  thereon as in  FIG. 5B , is inserted into the incision in the patient. The finger grips  38  of the sheath  12  and the tether  16  coupled to the tip  14  extend out of the body. If insufflation gas is being introduced into the body cavity through the insertion tube  210  or associated tubes, the holes  44  in the tip  14  allow the gas to pass into the body cavity. It should be noted that if an endoscope is to be positioned within the insertion tube or one of the associated access tubes for visualization during insertion of the system into the body, an optically transparent tip  14  may be used. 
         [0029]    After the insertion tube  210  has been advanced into the body, the user pulls on the tether  16  to detach the tip  14  from the distal end of the sheath  12 . The tip hangs freely within the body cavity, suspended from the tether. The user may couple a proximal portion of the tether  16  to the funnel  10  or to a portion of the access system  200  that remains outside the body. 
         [0030]    Next, the user retracts the sheath  12  to allow the tubes  212  and link arms  218  be exposed so they can deployed to an expanded position. To retract the sheath, the user pulls the finger grips  38  apart as discussed in connection with  FIG. 4 , thus peeling apart the longitudinal sections  41  of the sheath and causing the distal end of the sheath to slide proximally on the insertion tube  210 . Once the sheath has been retracted sufficiently to uncover the tubes  212  and link arms  218 , the link arms  218  may be actuated to deploy the tubes  212  to the position shown in  FIG. 6 . 
         [0031]    The sheath system  100  provides the user with a number of options concerning how to proceed at this point. The user can fully separate the longitudinal sections  41  of the sheath, and remove the longitudinal sections  41  from the funnel  10 , leaving only the funnel in place surrounding the insertion tube  210 . Once the user has finished using the access system  200 , s/he can withdraw access system  200  from the body, thereby removing the insertion tube  210  from the funnel  10  and leaving the funnel in place within the body incision. The funnel can thus serve as an access port through the incision, allowing other instruments or instrument systems to be used through the funnel  10 . 
         [0032]    In an alternate procedure, rather than fully separating the sheath, the more distal portion of the sheath can remain intact as shown in  FIG. 6 . If the user selects this method, the separated longitudinal sections  41  extend outside of the body and the intact distal portion of the sheath is disposed on the insertion tube  210 . The sheath  12  can remain in this position until the sheath system  100  and access system  200  are removed from the body. Alternatively, the distal portion of the sheath can be later used to cover or contain tissue extracted from the body cavity during the procedure. For example,  FIG. 7  shows a mass of tissue T engaged by an instrument I passed through tube  214 . In this figure, the tubes  212  and links  218  have already been moved back into the streamlined position for removal from the body. The user can choose to advance the intact distal portion of the sheath over the mass of tissue T by pushing the peeled longitudinal sections  41  of the sheath distally through the slots in the funnel  10 . If more complete containment of the tissue is desired, the tether  16  is manipulated to reposition the tip  14  on the distal end of the sheath. Once the tissue is contained, the systems  100  and  200  are removed from the body together. 
         [0033]    A second embodiment of a sheath system  110  is shown in  FIGS. 8 and 9 . The second embodiment differs from the first embodiment in that in the second sheath system  110 , the sheath  112  is not a peelable sheath. In this embodiment, the sheath may be made of polyolefin or other suitable material. During use of the sheath  112  with the access system  200  shown in  FIGS. 5A-7 , the sheath  112  is positioned covering the tubes  212  and links  218 , and the tip  14  is positioned on the distal end of the sheath  112  as described above. After the insertion tube  210  of the system  200  has been inserted into the body, the tip is detached using the tether  16  as described above. The sheath  112  is manually retracted in a proximal direction to expose the distal ends of the tubes  212  and links  218  and remains in place over the insertion tube  210  throughout the duration of the procedure. If desired, the sheath  112  may be distally advanced at a later stage for use in containing tissue to be removed from the body. 
         [0034]    While certain embodiments have been described above, it should be understood that these embodiments are presented by way of example, and not limitation. It will be apparent to persons skilled in the relevant art that various changes in form and detail may be made therein without departing from the spirit and scope of the invention. This is especially true in light of technology and terms within the relevant art(s) that may be later developed. 
         [0035]    Any and all patents, patent applications and printed publications referred to above are incorporated by reference.