Abstract:
A surgical snare device for engaging an object in a body passage and that employs multiple loops for snaring the object. The loops, which can be made from a single elongated line or separate lines, are positioned at locations that substantially span across the diameter of the body passage. A tubular membrane cap is included which is made from a liner coupled with structural elements made of expandable wire for support. The membrane cap is selectively deployed from a sheath and radially expandable to envelop the captured object so that withdrawing the object is more secure and any sharp edges on the object do not damage walls of the body passage. The loops and membrane cap can be made from a metal, a metal alloy, or polymer. Perforations can be formed in the liner to allow fluid to pass through the membrane cap.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority from U.S. Provisional Application Ser. No. 61/985,730, filed Apr. 29, 2014, and U.S. Provisional Application Ser. No. 62/105,316, filed Jan. 20, 2015, the full disclosures of which are hereby incorporated by reference herein for all purposes. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of Invention 
         [0003]    The present disclosure relates in general to a device insertable into a body passage, and which includes an elongated member fashioned into multiple coils for grappling objects in the passage, and a membrane cap that selectively deploys to encapsulate the object. 
         [0004]    2. Description of Prior Art 
         [0005]    Snares are typically used in body passages, such as blood vessels, and often under X-ray guidance to manipulate or retrieve intravascular devices and objects from within a body passage. Snares are also sometimes used to entrap and withdraw wires placed from another remote location, thereby establishing through wire access for device manipulation, such as is sometimes required for the placement of aortic stent grafts. Snares are also used for retrieving non-native objects such as stents, stent grafts, or vascular filters. Snares generally are made up of one or more loops that can be manipulated in concert with long thin plastic tubes, such as sheaths or catheters. Using two dimensional angiography and fluoroscopy, it can be difficult to navigate the snare to the exact three dimensional location inside the blood vessel, which is often required to engage the object that is to be snared. Moreover, currently known snares leave large gaps in the body passage, such as within the loops themselves, between the loops and luminal wall of the vessel, and between the snare and the object, which can create difficulty when attempting to snag or capture an object within the passage. 
       SUMMARY OF THE INVENTION 
       [0006]    Disclosed herein are examples of a device and method of capturing an object within a body passage. An embodiment of a surgical snare device is disclosed that includes a sheath, a control line in the sheath, an elongate member coupled with an end of the control line and that is selectively insertable into a body passage, and loops along the elongate member and defined where the elongate member is curved so that portions of the elongate member are in proximity with one another, and that are disposed at locations distal from the control line and that substantially circumscribe the sheath. In an embodiment, the loops are interconnected to one another. A plurality of control lines may optionally be included, wherein a one of the control lines each connect to a one of the loops, and that can optionally be circumscribed within an inner sheath. An annular membrane cap can optionally be included that circumscribes the control line or lines, and that is selectively moveable into a deployed configuration that circumscribes a portion of the loops and defines a barrier between the loops and an inner surface of the passage. In this example, the membrane cap includes a sheet like liner formed into a tubular member and elongate structural elements coupled within the liner, and wherein an open end of the membrane cap has a diameter that is selectively changeable. The membrane cap may be selectively moved from a retracted position within the sheath and to a deployed configuration with a portion extending axially outward past the sheath. In this embodiment a radius of the membrane cap flares outward with distance from the sheath when the membrane cap is in the deployed configuration, and has a trumpet like configuration and with a diameter greater than a diameter of the sheath. Perforations may optionally be formed in the liner. The surgical snare device can further optionally include a control line coupled to the membrane cap for selectively moving the membrane cap into the deployed configuration. The loops and the membrane cap can be disposed within the sheath when being inserted into the body passage. 
         [0007]    Also disclosed herein is an example of a surgical snare device that includes an elongated tubular sheath selectively insertable into a body passage, at least one loop deployable in the body passage that are each formed from an elongate filament line, that are controllable by a control line disposed in the sheath, and that occupy spaces across the body passage at a location distal from the sheath, and an annular membrane cap having at least a portion in the sheath, that circumscribes the control line, and that is selectively deployed from within the sheath to circumscribe the at least one loop. In an example, the annular membrane cap defines a protective layer between at least one loop and the walls of the body passage when in the deployed configuration. Multiple loops may optionally be included, and wherein the loops are formed from a single elongated element, and can have differing diameters. Optionally, manipulating the control line changes a diameter of the loop. 
         [0008]    A method of snaring an object within a body passage is described herein and which includes providing a surgical snare device that comprises a series of loops, each of the loops formed by a bend in an elongate member, inserting the surgical snare device into the body passage so that the loops are strategically disposed in spaces that span across the body passage at a location proximate to the object, and engaging the object with at least one of the loops. The surgical snare can also include a membrane cap that is made up of a tubular liner, in this example the method further includes, inserting the membrane cap into the sheath, pushing the membrane cap from the sheath, thereby causing a diameter of an opening of the membrane cap to expand, further urging the membrane cap in an axial direction so that the membrane cap is between the object and wall of the body passage to define a protective layer for the wall. Loop control lines can be included that couple to the elongate members, and a membrane cap control line, the method further including controlling the loops by manipulating the loop control lines, and separately controlling the membrane cap by manipulating the membrane cap control line. The loops can be disposed in the sheath when the sheath is disposed into the body passage. In an alternate example, the step of engaging the object with one of the loops involves manipulating a control line that couples to a one of the loops. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0009]    Some of the features and benefits of the present invention having been stated, others will become apparent as the description proceeds when taken in conjunction with the accompanying drawings, in which: 
           [0010]      FIG. 1A  is a partial sectional side view of an example of a snare device disposed in a body passage. 
           [0011]      FIG. 1B  is an axial sectional view of the snare device disposed in body passage and taken along lines  1 B- 1 B. 
           [0012]      FIG. 1C  is a partial side sectional view of an example of the snare device being inserted into body passage. 
           [0013]      FIG. 2  is a partial sectional side view of an alternate embodiment of the snare device of  FIG. 1 . 
           [0014]      FIGS. 3-5  show in a partial sectional side view alternate embodiments of snare devices each having a membrane cap. 
           [0015]      FIG. 6  is a partial sectional side view an example of the snare device of  FIG. 1  capturing an object in the body passage and a membrane cap deployed over a portion of the object. 
           [0016]      FIG. 7  is a partial sectional side view of an example of a snare device with a snare portion fully enveloped by a membrane cap. 
           [0017]      FIG. 8  is a partial sectional side view of an alternate embodiment of a snare device having control lines dedicated to specific snare loops. 
           [0018]      FIG. 9  is a partial sectional side view of an alternate embodiment of a snare device having a single control line for multiple snare loops. 
       
    
    
       [0019]    While the invention will be described in connection with the preferred embodiments, it will be understood that it is not intended to limit the invention to that embodiment. On the contrary, it is intended to cover all alternatives, modifications, and equivalents, as may be included within the spirit and scope of the invention as defined by the appended claims. 
       DETAILED DESCRIPTION OF INVENTION 
       [0020]    The method and system of the present disclosure will now be described more fully hereinafter with reference to the accompanying drawings in which embodiments are shown. The method and system of the present disclosure may be in many different forms and should not be construed as limited to the illustrated embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey its scope to those skilled in the art. Like numbers refer to like elements throughout. In an embodiment, usage of the term “about” includes +/−5% of the cited magnitude. In an embodiment, usage of the term “substantially” includes +/−5% of the cited magnitude. 
         [0021]    It is to be further understood that the scope of the present disclosure is not limited to the exact details of construction, operation, exact materials, or embodiments shown and described, as modifications and equivalents will be apparent to one skilled in the art. In the drawings and specification, there have been disclosed illustrative embodiments and, although specific terms are employed, they are used in a generic and descriptive sense only and not for the purpose of limitation. 
         [0022]    Shown in a side partial sectional view in  FIG. 1A  is one example of a snare device  10  and which is coaxially inserted into a body passage  12 . The body passage  12  could be within a human or animal. Examples exist where the passage  12  is a vessel or tube within the vascular system (such as a blood vessel); is part of a reproductive system, such as a fallopian tube or oviduct; is part of the renal and urinary system, such as an ureter, urethra, and bladder; is part of the lymphatic system; is part of the respiratory system, including bronchus, bronchioles, and alveoli; is part of the gastrointestinal system, such as the intestine, the stomach, gallbladder, cystic duct, bile duct, hepatic duct, pancreatic duct, and the spinal canal/intrathecal. The snare device  10  includes a snare element  14  on one end which is shown made up of a number of loops  16  that may selectively grapple or otherwise engage an object  17  that is within body passage  12 . The loops  16  are shown made up of where an elongate element  18  is curved, and where portions of the element  18  come in to close proximity with one another. Embodiments exist wherein all of the loops  16  are made from an element  18  that is a single member, or the loops  16  are made from an element  18  that is made up of multiple members. Further example embodiments exist wherein the loops  16  are separate from one another, or may optionally be interconnected or woven to one another. Example materials used to form the element  18  include alloys of nickel titanium (nitinol), woven nitinol, polymer, monofilament, nanofibers, combinations thereof, and the like. The loops  16  can have a wide range of shapes and circumferences, examples exist wherein the snare element  14  includes 1-20 loops  16 , 1-10 loops, or 4-10 loops. The element  18  can also have a wide range of diameters, such as in one example from about 0.06 mm to about 0.12 mm. 
         [0023]    Referring now to  FIG. 1B , which is taken along lines  1 B- 1 B of  FIG. 1A , it can be seen that the loops  16  are provided in locations that span across substantially all of the entire cross-section of body passage  12 . Further, in the illustrated example the loops  16  have portions that are in actual contact with a wall  20  formed along an inner surface of body passage  12 . An advantage of the strategic placement of the loops  16  throughout the passage  12  is that the ability of grabbing, and retrieving, an object  17  is increased over the use of a lesser number of loops. Referring back to  FIG. 1A , an optional membrane cap  22  is shown circumscribing a control line  23  that couples to an end of the snare element  14 . As will be described in more detail below, membrane cap  22  can be selectively deployed around the snare element  14  and object  17  and provide a protective barrier for the wall  20 . An annular outer sheath  24  is further illustrated and which houses portions of control line  23  and membrane cap  22 . Similarly, an optional inner sheath  25  covers the control line  23 , and alternatively a portion of snare element  14  proximate its connection to control line  23 . In the example of  FIG. 1A , inner sheath  25  is between control line and membrane cap  22 . Further illustrated in  FIG. 1A , is that membrane cap  22  is made up of a sheet-like liner  26  coupled with elongate structural elements that may selectively radially expand when being deployed axially outward from within outer sheath  24  and around snare element  14  and object  17 . An example of a matrix web  28  is shown provided in the liner  26 , which in one example can be a series of elongate members that are strategically formed within liner  26  to provide structural support for liner  26  and yet still allow for the radial expansion required for membrane cap  22 . In an embodiment, the membrane cap  22  is made up entirely of elongate structural elements and without a liner. In an alternative embodiment, the elongate members of the matrix web  28  include wire (potentially nitinol) similar to a stent, or the members could be a wire frame work that are coated. Examples exist wherein the coating on the members of the matrix web  28  is a polymer or fabric of some type. As shown, an opening or mouth of membrane cap  22 , depicted on an end projecting outward from outer sheath  24 , has a diameter greater than a portion of membrane cap  22  within outer sheath  24 . In an example, material of the membrane cap  22  is folds over proximate the circumference of opening to define a cuff (not shown). Moreover, in the illustrated example, the diameter of the membrane cap  22  gradually increases with axial length to initially define a trumpet-like configuration. Further shown in  FIG. 1A  is a control line  29  exiting an end of outer sheath  24  distal from snare element  14 ; by selectively actuating control line  29  the membrane cap  22  may be deployed from within sheath, or retracted fully within outer sheath  24 . 
         [0024]    Shown in a partial side sectional view in  FIG. 1C  is an example of snare device  10  being inserted into body passage  12 . In this embodiment, snare element  14  is fully retracted into outer sheath  24  to prevent it from inadvertently snagging against the side wall  20  of body passage  12 . Further retracted into outer sheath  24  is the membrane cap  22 . Selective manipulation of control line  23  (within inner sheath  25 ) can deploy snare element  14  from within outer sheath  24 . Similarly, manipulation of control line  29  can deploy membrane cap  22  from within outer sheath  24 . Alternatively, outer sheath  24  can be retracted to deploy membrane cap  22 . Further selective manipulation of control line  23  can optionally adjust a circumference of one of the loops  16  of snare element  14 , such as in an attempt to wrap the one of the loops  16  around an object  17  in order to bind it for retrieval from within the passage  12 . Alternatively, loops  16  can be adjusted independently from one another. 
         [0025]    Shown in  FIG. 2  is a side partial sectional view of an alternative example of snare device  10 A and which does not include a membrane cap  22 . In this embodiment the loops  16 A of the snare element  14 A project radially outward and into contact with wall  20 A of body passage  12 A, and at locations axially distal from outer sheath  24 A. Control line  23  is shown exiting inner sheath  25 A on an end distal from loops snare element  14 A. Similar to the embodiment of  FIG. 1A , manipulation of control line  23 A can selectively position snare element  14 A to capture an object  17  ( FIG. 1A ) so that object  17  can be withdrawn from passage  12 A. 
         [0026]      FIG. 3  shows another alternate embodiment of snare device  10 B where snare element  14 B is a single loop  16 B made up of a single element  18 B. Control line  23 B connects to snare element  14 B and extends within inner sheath  25 B. Here, a membrane cap  22 B is shown having a portion extending axially outward from the outer sheath  24 B, further axial extension of membrane cap  22 B allows it to radially encompass snare element  14 B. In the example of  FIG. 3 , the loop  16 B is disposed in a plane that is generally transverse to an axis A X  of body passage  12 B.  FIG. 4  shows an alternate embodiment of snare device  10 C in a side partial sectional view. This example of the snare device  10 C has a snare element  14 C which includes a single loop  16 C made from a single element  18 C; and where control line  23 B connects to snare element  14 B and extends within inner sheath  25 B. In this example, a membrane cap  22 C is included for selectively encompassing snare element  14 C. Here, loop  16 C lies in a plane that is generally parallel with an axis A X  of body passage  12 C. It should be pointed out that embodiments of any of the membrane caps described herein can be used with any type of snare device described herein. Moreover, the membrane caps described herein can be used with any type of snare device, and includes those not described herein. 
         [0027]    In another alternate embodiment of snare device  10 D shown in side sectional view in  FIG. 5 , snare element  14 D includes a number of loops  16 D that are each made from a single element  18 D. Here, a single control line  23 D connects to ends of each of the loops  16 D. Control line  23 D is circumscribed by inner sheath  24 , that in turn is circumscribed by membrane cap  22 D. In this example, loops  16 D are in planes that run generally parallel with axis A X  of body passage  12 D. Examples exist though where loops  16 D are disposed in planes that extend perpendicular or oblique to axis A X  of body passage  12 D. Further examples exist wherein the loops  16 D number about eight, or can range in number from about two to about twenty. Thus by engaging object  17  ( FIG. 1A ) with loops  16 D and axially extending membrane cap  22 D from within outer sheath  24 D, loops  16 D and membrane cap  22 D can selectively engage object  17  within passage  12 D so that object  17  can be removed from passage  12 D and without damaging walls of passage  12 D. 
         [0028]    Referring now to  FIG. 6 , shown in a side partial sectional view is one example of a membrane cap  22  being deployed axially outward from outer sheath  24 . Snare element  14  is anchored to control line  23 , which extends through inner sheath  25 . Here, matrix web  28  is being radially expanded to encompass snare element  14  and to define a barrier between snare element  14  and wall  20 . In this example, membrane cap  22  provides a protective layer for the wall  20  and prevents scratching or other damage to wall  20  either from snare element  14 , or from object  17  that is shown being engaged by loops  16  of snare element  14 . Examples of object  17  can be a blood clot, tissue, a stent, a stent-graft, a vascular filter, a wire, a vena cava filter, a kidney stone, a swallowed foreign object, as well as a catheter. Embodiments exist where the membrane cap  22  can extend from 6 to 7 centimeters in length. In the example of  FIG. 6 , perforations  32  are shown formed through the liner  26  and provide a passage for the flow of fluid, such as blood, through liner  26  so that when object  17  and/or snare element  14  is encompassed within membrane cap  22 , the object  17  can then be removed from within body passage  12 . Optionally, slits, pores, or interstices (not shown) can be provided in the liner  26  in addition to or in place of the perforations  34 . Further, object  17  may contain sharp edges  34  on its outer surface that could be damaging to wall  20 , thus another advantage of liner  26  is its ability to isolate wall  20  from sharp edges  34 . Moreover, separate control lines  23 ,  29  allow for selective deployment/operation of snare element  14  with control line  23 , and selective deployment/operation of membrane cap  22  with control line  29 . Thus snare element  14  can be manipulated separately from the manipulation of membrane cap  22  by separate operation of control lines  23 ,  29 . Examples exist wherein membrane cap  22  can retract entirely within outer sheath  24 , such as when snare device  10  is being inserted into passage  12 . In one example, the opening of the membrane cap  22  can have a diameter that is at least twice that of a diameter of the outer sheath  24 . In yet another alternate example, the opening of membrane cap  22  can have a diameter that is at least two to five times a diameter of outer sheath  24 . Thus, manipulating control line  23  can deploy and/or retract snare element  14 , and also adjust the circumference of one or more loops  16  within snare element  14 . Similarly, manipulating control line  29  can deploy and/or retract membrane cap  22 , and also adjust the size of the opening of membrane cap  22 , i.e. splay it open so that it can encompass snare element  14  and or object  17  as well as reduce its diameter for reinsertion back into outer sheath  24  or held stationary outside the opening of outer sheath  24  if the diameter of captured object exceeds the diameter of outer sheath  24 . In one alternate embodiment, material making up web matrix  28  is compressed when being inserted into outer sheath  24 , thus by axially retracting sheath from an end of membrane cap  22 , the circumferential restraint of the outer sheath  24  is removed allowing web matrix  28  to expand radially outward and without the need for a control line to cause the expansion. 
         [0029]      FIG. 7  shows in a side partial sectional view one optional embodiment of snare device  10 E wherein membrane cap  22 E has been deployed such that it extends axially past all of the snare element  14 E and its coils  16 E, as well as object  17 E and covers a terminal end of snare element  14 E distal from the open end of outer sheath  24 E. Membrane cap  22 E is substantially closed on this terminal end  36 E to define a small opening, a loop  38 E around opening can be selectively opened and closed with control line  40 E shown passing through loop  38 E and spanning across membrane cap  22 E and back into outer sheath  24 E to modify the diameter of the cap opening. Control lines  29 E and  40 E are shown exiting an end of outer sheath  24 E distal from snare element  14 E, so that personnel operating snare device  10 E can separately operate each membrane cap  22 E, and control line  40 E. Control line  23 E is shown exiting inner sheath  25 E, and by selective manipulation of which snare element  14 E can be controlled. 
         [0030]    Shown in side partial sectional view in  FIG. 8  is an alternate embodiment of snare device  10 F where snare element  14 F is shown made up of a number of loops  16 F and where loops span the inner space of body passage  12 F. Moreover, a series of control lines  42 F are shown each connecting to a single one of loops  16 F so that control of each loop  16 F may be performed independently from one another. Control lines  42 F pass through outer and inner sheathes  24 F,  25 F at a distance based axially apart from ends of loops  16 F.  FIG. 9  shows in a side partial sectional view an example of an alternate embodiment of snare device  100  where snare element  14 G includes a plurality of loops  16 G, where loops  16 G are operated by a single control line  44 G that passages through outer and inner sheathes  24 G,  25 G. Here the loops  16 G project radially outward and into contact with wall  200  of passage  14 G. Examples exist though where loops  16 G are disposed in planes that are parallel with, extend perpendicular to, or are oblique to axis A X  of body passage  12 G. Further examples exist wherein the loops  16 G number about eight, or can range in number from about two to about twenty. Although not shown, a membrane cap  22  ( FIG. 1 ) can be included on the embodiments of the snare devices  10 F,  100  of  FIGS. 8 and 9 . In the loops  16 F,  16 G of  FIGS. 8 and 9 , selectively manipulating the associated control lines  42 F,  42 G can alter a circumference of the loops  16 F,  16 G. For example, by pulling a one of control lines  42 F in a direction away from loops  16 F, the circumference of an associated one of loops  16 F (i.e. connected to the one of the control lines  42 F) can be reduced so that the associated one of the loops  16 F can come into close contact with and thus bind an object. 
         [0031]    The present invention described herein, therefore, is well adapted to carry out the objects and attain the ends and advantages mentioned, as well as others inherent therein. While a presently preferred embodiment of the invention has been given for purposes of disclosure, numerous changes exist in the details of procedures for accomplishing the desired results. These and other similar modifications will readily suggest themselves to those skilled in the art, and are intended to be encompassed within the spirit of the present invention disclosed herein and the scope of the appended claims.