Abstract:
A device for accessing tissue within a body lumen comprises an elongated body portion defining a lumen and an anchoring mechanism including an expanding structure on a distal portion of the elongated body portion. The anchoring mechanism moves the expanding structure from an insertion configuration in which the expanding structure is constricted against the device to an operative configuration in a body in which the expanding structure expands away from the device without altering a length of the anchoring mechanism in combination with a control mechanism for selectively engaging the anchoring mechanism.

Description:
PRIORITY CLAIM 
       [0001]    This application claims the priority to the U.S. Provisional Application Ser. No. 61/020,556, entitled “Endoscope Anchoring Device” filed Jan. 11, 2008. The specification of the above-identified application is incorporated herewith by reference. 
     
    
     BACKGROUND 
       [0002]    Endoscopes are often inadvertently moved away from target locations within body lumens. This may result from forces accidentally applied to the endoscope, natural body motion, muscular activity (e.g., peristalsis) and/or resistances to the positioning of the endoscope accumulated during insertion. Such inadvertent movement of an endoscope relative to a target location may cause discomfort and/or trauma and may complicate and/or reduce the efficacy of the procedure. 
       SUMMARY OF THE INVENTION 
       [0003]    The present invention is directed to a device for accessing tissue within a body lumen, the device comprising an elongated body portion defining a lumen and an anchoring mechanism including an expanding structure on a distal portion of the elongated body portion, the anchoring mechanism moving the expanding structure from an insertion configuration in which the expanding structure is constricted against the device to an operative configuration in a body in which the expanding structure expands away from the device without altering a length of the anchoring mechanism in combination with a control mechanism for selectively engaging the anchoring mechanism. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0004]      FIG. 1  shows a side view of a device according to a first exemplary embodiment of the present invention in position within a body lumen; 
           [0005]      FIG. 2  shows a side view of a device according to a second exemplary embodiment of the present invention in position within a body lumen; 
           [0006]      FIG. 3  shows a side view of a device according to a third exemplary embodiment of the present invention in position within a body lumen; 
           [0007]      FIG. 4  shows a side view of a device according to a fourth exemplary embodiment of the present invention in position within a body lumen; 
           [0008]      FIG. 5  shows a side view of a device according to a fifth exemplary embodiment of the present invention in position within a body lumen; 
           [0009]      FIG. 6  shows a side view of a device according to a sixth exemplary embodiment of the present invention in position within a body lumen; 
           [0010]      FIG. 7  shows a side view of a device according to a sixth exemplary embodiment of the present invention in position within a body lumen; 
           [0011]      FIG. 8  shows a side view of a device according to a seventh exemplary embodiment of the present invention in position within a body lumen; and 
           [0012]      FIG. 9  shows a side view of a device according to an eight exemplary embodiment of the present invention in position within a body lumen. 
       
    
    
     DETAILED DESCRIPTION 
       [0013]    The present invention, which may be further understood with reference to the following description and the appended drawings, relates to devices and methods for securing endoscopes in desired positions within body lumens. For example, the present devices and methods may be used to secure an endoscope in a body lumen such as the duodenum, esophagus, large intestine, gastrointestinal tract, etc. It is submitted that, although the exemplary embodiments of the present invention are described with respect to particular lumens and procedures, they are not meant to limit the applicability of the present invention. 
         [0014]    Devices and methods according to the present invention employ an endoscope provided with a gripping portion formed on a distal end thereof. It is noted that the use of the term distal herein refers to a direction away from a user of the device while the term proximal refers to a direction approaching the user of the device (e.g., a physician). Proximal portions of the devices disclosed herein remain external to the patient when in an operative position while distal portions of the device are inserted into the body, for example, via a naturally occurring orifice and one or more body lumens. 
         [0015]    As shown in  FIG. 1 , a device  100  according to a first embodiment of the invention includes an endoscope  100  with an anchoring mechanism  150  formed on a distal end  102  thereof. The anchoring mechanism  150  engages tissue (e.g., lumenal tissue  140 ) to resist movement of the endoscope  101  relative thereto. In use, a user inserts the endoscope  101  through the lumen  140  to a target location. Those skilled in the art will understand that the target location is often specific to the procedure being performed and the anatomy of the individual patient and may, for example, be located using a vision system formed in the distal end  102  of the endoscope  101 . As would be further understood by those skilled in the art, the endoscope  101  is preferably sufficiently flexible to conform to curvatures in the lumen  140  while maintaining a degree of longitudinal rigidity required to transmit to the distal end  102  forces applied to a proximal portion  104  to urge the endoscope  101  distally through the lumen  140  without bunching in the lumen  140 . 
         [0016]    The anchoring mechanism  150  includes a plurality of retractable ribs  151  coupled to an actuator  120  on a proximal end  104  of the endoscope  101  (i.e., formed on a portion of the endoscope  101  which remains accessible to the user throughout the procedure). The ribs  151  are preferably maintained in a retracted position in which they lie substantially flat along an outer surface  103  of the endoscope  101  to minimize a profile thereof during insertion and retraction of the endoscope through the lumen  140  to minimize trauma to lumenal tissue. Then, when the endoscope  101  has reached a desired location within the lumen  140  and it is desired to maintain the endoscope  101  in this position, the user operates the actuator  120  to move the ribs  151  away from this insertion configuration to a deployed configuration in which the ribs  151  extend radially outward from the outer surface  103  to frictionally engage the walls of the lumen  140 . Proximal ends of the ribs  151  may, for example, be coupled to a ring  153  slidably mounted within the outer surface  103  while distal ends of the ribs  151  are fixed in place. In the insertion configuration, the ring  153  is withdrawn proximally so that the ribs  151  lay flat against the outer surface  103  of the endoscope  101 . When the actuator  120  is operated to move the ribs  151  to the deployed configuration, the ring  153  is urged distally by, for example, a flexible pushing member  122  coupled between the ring  153  and the actuator  120 . As the ring  153  moves distally, the ribs  151  are longitudinally compressed causing them to bow radially outward (e.g., via slots in the outer surface  103 ). The actuator  120  may then be locked in this position using any known mechanism (e.g., friction fit, ratchet mechanism, etc.) to maintain the anchoring mechanism  150  in the deployed configuration until the user wishes to remove the endoscope  101  or to move it to another location in the lumen  140 . At this point, the user moves the actuator  120  to its original position allowing the anchoring mechanism  150  to return to the insertion configuration with the ribs  151  lying flat within slots in the outer surface  103 . Those skilled in the art will understand that the anchoring mechanism may be moved from the deployed to the insertion configuration under a spring bias of the ribs  151 , through the motion of the actuator  120  of via any other suitable known mechanism. 
         [0017]    The bowed shape and lateral extent of the actuated ribs  151  is preferably selected to engage the walls of a lumen  140  with a desired force sufficient to hold the endoscope  101  in place in the lumen  140 , as shown in the embodiment of  FIG. 1 , even when subjected to inadvertent forces of an expected magnitude. As would be understood by those skilled in the art, the pushing member  122  may be replaced by a system of filaments and pulleys to move the ring  153  proximally and distally as desired or by any other suitable mechanism or combination of mechanisms. 
         [0018]    The ribs  151  preferably comprise a flexible, substantially biocompatible material (e.g., a plastic such as Polyetheretherketone (“PEEK”), polyimide, etc. or a metal such as Nitinol, stainless steel, etc.). Furthermore, the ribs  151  may be substantially equally dispersed about the circumference of the endoscope  101  to center the endoscope  101  within the lumen  140 . Alternatively, as would be understood by those skilled in the art, if it is desired that a particular side of the endoscope  101  be located adjacent to a wall of the lumen  140 , the ribs  151  may be sized appropriately around the endoscope  101  to achieve any desired position of the distal end  102  within the lumen  140 . 
         [0019]    In addition, the length (extent parallel to a longitudinal axis of the endoscope  101 ) and width (extent perpendicular to the longitudinal axis) of each of the ribs  151  may be the same or, in the alternative, may vary to achieve any desired distribution of the anchoring force to the portions of the walls of the lumen  140 . Furthermore, the contacting surface of each of the ribs  151  may be composed of a high friction material or, alternatively, the contacting surface may be a ribbed surface with a plurality of protrusions such as bumps to aid in gripping the walls of the lumen  140 , as those skilled in the art will understand. Furthermore, the ribs  151  may be formed of different shapes and need not be formed in the arc shape shown in  FIG. 1 . For example, as shown in  FIG. 2 , the device  100  may comprise ribs  152  each of which contains a series of bends and curves along a longitudinal length thereof. As would be understood by those skilled in the art, the bends may increase a gripping force exerted thereby to the lumen  140 . The design of the ribs  152  may comprise any plurality of bends and curves therein. 
         [0020]    As described above, the endoscope  101  is inserted into the lumen  140  with the anchoring mechanism  150  in the insertion configuration (i.e., with the ribs  151  flat against the outer surface  103 ) to minimize trauma to the lumen  140 . Once a user of the endoscope  101  has traversed the endoscope  101  to a target area, the actuator  120  is moved to a distal-most position, thereby engaging the ribs  151  with the walls of the lumen  140 . The actuator  120  may further be provided with a locking feature or friction fit design to prevent the actuator  120  from sliding prematurely. When a designated procedure is complete, the actuator  120  may once again be retracted and the endoscope  101  may be removed from the lumen  140 . Although the actuator  120  has been described as a slidable trigger, the actuator  120  may be triggered in any suitable manner (i.e., push-button trigger, etc.) without deviating from the spirit and scope of the present invention. Furthermore, it is noted that the device  100  may be sized to minimally obstruct a working channel of an endoscope, so as to allow ample space for tool delivery therethrough. 
         [0021]    As shown in  FIG. 3 , a device  200  according to a second embodiment of the present invention includes an endoscope  201  which may be employed in a manner similar to that of the embodiment of  FIG. 1 . The endoscope  201  may be provided with an actuator  220  that may be used to retract and expand a anchoring mechanism  250  located on a distal end  202  thereof. The anchoring mechanism  250  comprises a series of flexible wires  251 , each extending around a section of the distal end  202  of the endoscope  201 . The flexible wires  251  may be formed of a wire material such as Nitinol or stainless steel which can withstand high amounts of elastic deformation before a permanent deformation sets in, as those skilled in the art will understand. Each of the flexible wires  251  extends out of a corresponding pair of holes  255  placed separated from one another around the circumference of the distal end  202  substantially equally positioned along the length of the endoscope  201 . Each of the flexible wires  251  may be connected, by known means, to an internally located control cable or filament  222  extending to an actuator  220  on a proximal portion  204  of the endoscope  201 . Each of the flexible wires  251  acts as a radial spring, wherein each loop of the flexible wires  251  may be connected to the control cable or filament  222 . 
         [0022]    As described above in regard to the endoscope  101 , when the endoscope  201  is being traversed to a target area in the body, the anchoring mechanism  250  is maintained in an insertion configuration wherein each of the flexible wires  251  is constricted to fit snugly around a radial portion of the endoscope  201 . Specifically, retraction of the control cable or filament via the actuator  220  may exert a force on each of the flexible wires  251 , pulling a length of each of the flexible wires  251  into the endoscope  201  and causing the restriction of each of the flexible wires  251  against the endoscope  201 . Once a target area has been reached, the user moves the actuator  220  distally to expand the flexible wire  251  radially outward to place a desired amount of pressure on the walls of the lumen  240 , securing the endoscope  201  in place. Specifically, the actuation of the actuator  220  forces a length of each of the flexible wires  251  out of the endoscope  201 , thereby increasing a radial length of each loop formed therein. The increased radial length of each of the loops made by the flexible wires  251  causes a radial expansion, thereby engaging the flexible wires  251  with the inner walls of a lumen. When the procedure has been completed, the user operates the actuator  220  to move the anchoring mechanism  250  to the insertion configuration to release the endoscope  201  for movement through the lumen  240  to a new target location or for removal from the body. 
         [0023]    As shown in  FIG. 4 , a device  300  according to yet another embodiment of the present invention comprises an endoscope  301  with a anchoring mechanism  350  located on a distal end  302  thereof. As with the previously described embodiments, the anchoring mechanism  350  is withdrawn into an insertion configuration before the endoscope  301  is inserted into a lumen  340  and advanced therethrough. The anchoring mechanism  350  of the embodiment of  FIG. 3  comprises a coil  351  extending around a portion of the distal end  302  of the endoscope  301 . As would be understood by those skilled in the art the coil  351  may be formed of any suitable biocompatible material such as, for example, Nitinol, pre-formed stainless steel wire cables, similar to snare loop cables or polymers. 
         [0024]    A proximal end of the coil  351  may be connected to a deploying mechanism which is, in turn, coupled to an actuator (not shown) as in the previous embodiments. The deploying mechanism may include, for example, a ring  353  coupled to the actuator via a cable or filament(s)  322  to move the anchoring mechanism  350  between the insertion configuration in which the wire  351  is snugly received around the distal end  302  of the endoscope  301  and a deployed configuration in which the wire  351  is radially expanded to engage tissue of the lumen  340  to anchor the distal end  302  in a target position. It may be particularly advantageous to employ a material with shape memory properties herein, as such a material can retain a deployment shape (i.e., an expanded coil shape) for an extended period of time while strained to a high level, such as in the insertion configuration, as detailed below. Actuation of the coil  351 , which may exhibit shape memory properties as noted above, may be similar to that of the embodiment of  FIG. 2 . Specifically, actuation of a proximally located actuator (not shown) may cause the cable or filament  322  to move distally, thereby causing the coil  351  to expand radially and conform to the walls of the lumen  340 . Conversely, a retraction of the actuator (not shown) may cause the cable or filament  322  to move proximally, thereby shortening the radial length of the coil  351  and causing a constriction of the coil  351  against the endoscope  301 . As would be understood by those skilled in the art, the outer surface of the distal end  302  may include a recess within which the wire  351  may be received when in the insertion configuration so that the outer surface is substantially smooth. The wire  351  can extend out of a proximal slit  360  formed on the outer surface of the endoscope  301  and coils around the distal end  302  to a distal slit  361  through which the wire  351  re-enters the endoscope  301  to which the distal end of the wire  351  is attached, for example, via any known means such as bonding or welding. In an alternate embodiment, the wire  351  may be attached to a component such as a ring, which is, in turn, attached or releasably attached to the endoscope  301 . 
         [0025]    As would be understood by those skilled in the art, the size and shape of the wire  351  is preferably selected so that a desired anchoring force is applied to the tissue of the lumen  340  (i.e., a desired frictional engagement is established between the endoscope  301 , and the surrounding tissue) when the anchoring mechanism is in the deployed configuration. The wire  351  may be formed, for example, as a substantially planar ribbon with a surface that may be textured or otherwise treated or coated to enhance the frictional engagement of the surrounding tissue. In these cases, the endoscope  301  may include an optional cover which, when in the insertion configuration, eliminates contact between the wire  351  and the surrounding tissue. The wire  351  may have a cross-section that is substantially circular, elliptical, triangular, square, or of any other desired shape. The employment of cross sectional shapes other than round, smooth shapes provides corners or edges that may aid in anchoring the wire  351  in the body and provide an additional locking force thereto. Additionally, the surface of the wire may be smooth or ribbed with a plurality of protrusions to increase the gripping ability of the anchoring mechanism  350 . 
         [0026]    In a further embodiment of the present invention, as shown in  FIG. 5 , the anchoring mechanism  450  comprises a flexible wire  451  which is formed as a unitary element with a cable or filament extending through an endoscope  401 . A distal end of the anchoring wire  451  may be attached to a joint portion  452  on the endoscope  401  while a proximal end of the anchoring wire  451  may be connected to an actuator (not shown) located on a proximal portion of the endoscope  401 . The anchoring wire  451  may span the longitudinal length of the endoscope  401  and extend therefrom via an opening or slit  460  located on a distal length. A distal length of the anchoring wire  451 , which is comprised of a shape memory material such as Nitinol, may be shape memorized in a shape such as a series of petals or a series of bends which expand radially outward from the endoscope  401  when actuated. Those skilled in the art will understand that the anchoring wire  451  may move into its memorized shape through the application of heat, through the action of body heat, by applying a small electrical jolt thereto. Alternately, the anchoring wire  451  may run alongside a portion of the outer body of the endoscope  401 , wherein the wire  451  may be joined to the endoscope  401  along a distal length thereof with length of the joint portion  452  being indicative of a longitudinal length of the anchoring portion of the anchoring mechanism  450 . 
         [0027]    In a further embodiment, as shown in  FIGS. 6 and 7 , the anchoring mechanism  550  may comprise an anchoring wire  551  which extends out of an endoscope  501  via an opening  560  provided on a distal portion thereof. The anchoring wire  551  is further attached to a distal portion of the endoscope  501  at a joint portion  552 . In an insertion configuration, an actuator (not shown) located on a proximal portion of the endoscope  501  may be retracted to keep a portion of the anchoring wire  551  extending between the joint portion  552  and the opening  561  constricted against the body of the endoscope  501 . Accordingly, when the anchoring mechanism  550  is actuated, as shown in  FIG. 7 , a length of the anchoring wire may extend out of the opening  561  and may be further actuated to assume a shape memorized configuration which, in this embodiment, may be a coiled shape. In an alternate embodiment, a plurality of anchoring wires  551  may be provided wherein, when actuated, the plurality of anchoring wires  551  extend around the circumference of the endoscope  501  and provide an anchoring means on all sides thereof. 
         [0028]    It is submitted that the features of each of the aforementioned embodiments of the present invention may be combined in any manner to create a device having desired performance characteristics without deviating from the spirit and scope of the present invention. For example, the anchoring mechanisms according to any of the disclosed embodiments of the present invention may be employed in a sterility sheath or other device through which an endoscope or other device is to be inserted to anchor the sheath in a desired location within a body lumen. Such an embodiment may add to the utility of the present invention when traversing difficult regions of the digestive tract and through other tortuous parts of the body, as those skilled in the art will understand. Those skilled in the art will understand that, although devices such as the endoscopes and sheaths described herein are often inserted into body lumens via naturally occurring body orifices, these devices may be inserted into hollow organs or body lumens via surgical openings, wounds, etc. as desired without impacting the operation of the anchoring mechanisms. 
         [0029]    In another embodiment, the anchoring device of the present invention may be integral to an endoscope or, alternatively, can be fixedly or releasably attachable to an endoscope. Furthermore, the anchoring device need not cover the full length of the endoscope to which it is attached but rather, may alternately be attached only to a distal portion thereof. In such an embodiment, the anchoring mechanism may be actuated in a manner similar to that of the embodiments of  FIGS. 1-4 , wherein the actuating cable or filament may extend either outside of the endoscope or within a working channel of the endoscope. In another embodiment, the anchoring device may be integral to a sheath, wherein wires of the anchoring device may be embedded within the sheath and the distally located anchoring mechanism may extend out of the device along a distal length. As indicated above, the device of the present invention may be employed in a sterility sheath. Alternatively, any of the embodiments of the invention may be incorporated in an endoscope or other device through a surrounding sheath. In such an embodiment, the user moves the endoscope or other device through the sheath to a target location and deploys the anchoring mechanism. The anchoring mechanism pushes the flexible sheath out ward into contact with the lumenal tissue to anchor the sheath and the endoscope in place. 
         [0030]    In yet another alternate embodiment, the device of the present invention, as described in  FIGS. 3-5  may comprise any plurality of anchoring wires, wherein the increased number of wires may directly correlate to an increased gripping force exerted by the anchoring mechanism or to a more evenly distributed anchoring force, as those skilled in the art will understand. 
         [0031]    In another alternate embodiment, the device of the present invention may employ suction to aid in anchoring the endoscope at a target site within the body. Specifically, as shown in  FIG. 8 , an endoscope  600  is provided with an opening  602  fluidly coupled to a suction lumen (not shown) along a lateral side of a distal portion thereof The opening  602  is sized to permit a cone  604  to extend therefrom. The cone  604  is a hollow element extending from a minimum diameter at a proximal lip  606  to a maximum diameter at a distal lip  608 . The proximal lip  606  further comprises a flange  610  that flutes outward to assume a diameter greater than a diameter of the proximal lip  606 . The flange  610  may preferably be permanently attached to the endoscope  600  to prevent the cone  604  from being dislodged therefrom. 
         [0032]    The cone  604  is formed of a substantially flexible biocompatible material to permit proximal and/or distal deflection thereof during insertion to a target location in a body lumen  640 . Once the target location has been reached, suction is applied at a proximal end of a lumen  614  of the endoscope  600  to cause the cone  604  to attach to a wall of the body lumen  640 . A guiding device  612  is then inserted into the lumen  614  to a location extending partially laterally out of the lumen  614  and into the cone  604 , as shown in  FIG. 8 . A guide wire  616  is actuated to extend distally out of the guiding device  612  and attach to the wall of the body lumen  640 . An attachment  618  of the guide wire  616  may comprise, for example, a knot, hook, latch, or other attachment mechanism known in the art. Thus, suction applied to the cone  604  helps maintain a position of the cone  604  against the wall of the body lumen  640  while the attachment  618  of the guide wire  616  locks the endoscope and further aids in preventing longitudinal movement of the cone against the wall of the body lumen  640 . The embodiment of  FIG. 8  permits a centering of a position of the endoscope relative to walls of the body lumen  640 . Alternatively, the cone  604  may assume any suitable dimension to permit any positioning of the endoscope  600  relative the body lumen  640 , as those skilled in the art will understand. 
         [0033]      FIG. 9  depicts another alternate embodiment of the present invention, in which a suction opening is formed through a wall of an endoscope  700 . Specifically, the endoscope  700  is formed substantially similarly to the endoscope  100  with the exception of a suction window  702  formed on a portion of an outer wall thereof. The suction window  702  may be dimensioned to suit the requirement of a body lumen  740  into which the endoscope  700  is inserted. Furthermore, the suction window  702  may extend over any portion of the endoscope  700  wall without deviating from the spirit and scope of the present invention. A visualization window  704  may be formed on the endoscope  700  on a location opposite the suction window  702 . The visualization window  704  may be formed as an outlet for distal ends of optical fibers extending longitudinally through the endoscope  700 , as those skilled in the art will understand. Alternatively, the visualization window  704  may permit visualization of the body lumen  740  using any means known in the art. Positioning the visualization window  704  opposite the suction window  702  allows an unobstructed view of the body lumen  740  in an operative configuration. Specifically, when a suction force is applied to a proximal portion of the lumen  706  of the endoscope  700 , the suction window  702  is automatically drawn into contact with an adjacent surface of the body lumen  640 , thus centering the visualization window  704  therein. 
         [0034]    The present invention has been described with reference to specific exemplary embodiments. Those skilled in the art will understand that various modifications and changes may be made to the embodiments. The specification is, therefore, to be regarded in an illustrative rather than a restrictive sense.