Tissue engagement devices, systems, and methods

Abstract

Devices and related methods to engage tissue layers to access the space between the layers are provided. The access devices include engagement arms that can be deployed and retracted to easily engage the top tissue layer and allow it to be separated from the underlying layer. The engagement arms are coupled to an actuation rod that is in turn coupled to a switch or lever that allows a user to control the actuation from outside the patient. The engagement arms and coupling to the actuation rod are unique and compact to ensure the entire mechanism fits in a small diameter shaft.

1 . A tissue engagement device comprising:
 a tube that defines a lumen and extends longitudinally, the tube further defining a maximum exterior width;   an actuation rod positioned within the lumen of the tube;   a plurality of arms pivotally coupled to one or more of the tube and the actuation rod, each arm comprising a tip; and   an actuator configured move the actuation rod to transition the arms between (i) a retracted orientation in which the tips of adjacent arms are directed inwardly and define a gap into which a portion of a tissue layer can be received and (ii) an actuated orientation in which the tips are directed outwardly and are spaced from each other by a distance greater than the maximum exterior width,   wherein, as the arms are rotated from the retracted orientation to the actuated orientation, the tips are rotated into the portion of the tissue layer received in the gap and bypass each other in opposite directions.   
     
     
         2 . The tissue engagement device of  claim 1 , wherein the actuation rod comprises a distal tip, and wherein the gap into which the portion of the tissue layer can be received is laterally adjacent to the distal tip. 
     
     
         3 . The tissue engagement device of  claim 1 , wherein the tips of the arms pierce an outer surface of the tissue layer and engage an inner surface of the tissue layer as the arms are transitioned from the retracted orientation to the actuated orientation. 
     
     
         4 . The tissue engagement device of  claim 1 , wherein the tips of the arms extend distally past the distal tip of the actuation rod during at least a portion of a transition from the retracted orientation to the actuated orientation. 
     
     
         5 . The tissue engagement device of  claim 1 , wherein the tips of the arms extend distally past a distal end of the tube during at least a portion of a transition from the retracted orientation to the actuated orientation. 
     
     
         6 . The tissue engagement device of  claim 1 , wherein an imaginary longitudinal plane extends along a longitudinal axis defined by the tissue engagement device, and wherein each tip of plurality of arms passes through the longitudinal plane as the arms transition from the retracted orientation to the actuated orientation. 
     
     
         7 . The tissue engagement device of  claim 6 , wherein the tips of the arms pass through the longitudinal plane at a region that is distally spaced from a portion of the actuation rod to which the arms are attached. 
     
     
         8 . The tissue engagement device of  claim 1 , wherein each arm is rigid. 
     
     
         9 . The tissue engagement device of  claim 1 , further comprising a post attached to the actuation rod, wherein at least one of the plurality of arms is pivotally coupled to the post. 
     
     
         10 . A tissue engagement device comprising:
 a tube that defines a lumen having a maximum interior width;   an actuation rod positioned within the lumen of the tube;   a plurality of arms pivotally coupled to the actuation rod, each arm comprising a piercing tip; and   an actuator configured to move the actuation rod relative to the tube to rotate the arms between (i) a retracted orientation in which the tips of adjacent arms are at a distance from each other that is less than the maximum interior width of the lumen and (ii) an actuated orientation in which the tips of adjacent arms are directed away from each other and are spaced from each other by a distance that is greater than the maximum interior width,   wherein, when a distal end of the tissue engagement device abuts a layer of tissue, actuation of the arms via the actuator rotates the tips into the layer of tissue to pierce the layer of tissue and to apply tension to the layer of tissue outwardly in opposite directions.   
     
     
         11 . The tissue engagement device of  claim 10 , wherein each arm comprises a rounded side that extends from the tip of the arm, the rounded side being configured to inhibit trauma to additional tissue positioned beneath the layer of tissue as the rounded side rotates against the additional tissue, and wherein the rounded side of each arm faces distally from the tissue engagement device throughout an entirety of a transition from the retracted orientation to the actuated orientation to inhibit trauma to the additional tissue. 
     
     
         12 . The tissue engagement device of  claim 10 , wherein the tips of the arms face each other when the tissue engagement device is in the retracted orientation and define a gap into which the layer of tissue layer can be received when the distal end of the tissue engagement device is pressed into the tissue layer. 
     
     
         13 . The tissue engagement device of  claim 10 , wherein the tips of the arms face away from each other when the tissue engagement device is in the retracted orientation. 
     
     
         14 . The tissue engagement device of  claim 10 , wherein the distance at which the tips of adjacent arms are spaced from each other when the arms are in the retracted state is substantially zero. 
     
     
         15 . A tissue engagement device comprising:
 a tube defining a longitudinal axis and comprising a distal end having a face that defines an acute angle relative to the longitudinal axis to permit the face of the tube to rest against a tissue layer while the tube is at the acute angle relative to the tissue layer;   an actuation rod positioned within the lumen of the tube;   a plurality of rigid arms pivotally coupled to the actuation rod, each arm comprising a tip; and   an actuator configured to translate the actuation rod proximally relative to the tube to transition the arms between a retracted orientation and an actuated orientation,   wherein, as the arms are rotated from the retracted orientation to the actuated orientation, they move outwardly beyond the distal end of the tube and away from each other relative to the longitudinal axis.   
     
     
         16 . The tissue engagement device of  claim 15 , wherein the tips of the arms face each other when in the retracted orientation and define a gap into which the layer of tissue layer can be received when a distal end of the actuation rod is pressed into the tissue layer. 
     
     
         17 . The tissue engagement device of  claim 15 , wherein the tips of the arms face away from each other when in the retracted orientation. 
     
     
         18 . A tissue engaging device comprising:
 a tube that defines a lumen and an outer diameter at a distal end thereof;   an actuation rod positioned within the lumen of the tube;   a plurality of arms pivotally coupled to the actuation rod, each arm comprising a piercing tip and a shelf; and   an actuator configured to transition the tissue engagement device between (i) a retracted orientation in which no portion of the plurality of arms are distanced from each other by an amount greater than the outer diameter of the distal end of the tube and (ii) an actuated orientation in which the tips are rotated through an outer surface of a first tissue layer and into an interior space between the first tissue layer and a second tissue layer and face away from each other and the shelves are extended laterally to engage a lower surface of the tissue layer.   
     
     
         19 . A method of engaging a first tissue layer that is positioned above a second tissue layer, the method comprising:
 positioning a distal end of a tissue engaging device against the first tissue layer, the tissue engaging device comprising a distal end, a first arm that comprises a first tip, and a second arm that comprises a second tip;   rotating the first and second arms in opposite directions to bypass each other;   piercing the first tissue layer with the first and second tips without piercing the second tissue layer at a position that is distal to the distal end of the tissue engaging device as the first and second arms are rotated in opposite directions past each other.   
     
     
         20 . The method of  claim 19 , further comprising positioning a portion of the first tissue layer between the first and second tips prior to said piercing. 
     
     
         21 . The method of  claim 19 , wherein the first and second arms comprise first and second rounded surfaces, respectively, the method further comprising facing the rounded surfaces of the first and second arms toward the second layer of tissue throughout said piercing to inhibit traumatization of the second tissue layer. 
     
     
         22 . The method of  claim 19 , wherein an imaginary longitudinal plane extends along a longitudinal axis defined by the tissue engagement device, the method further comprising passing the first and second tips through the longitudinal plane during said rotating. 
     
     
         23 . The method of  claim 19 , wherein the first arm comprises a first shelf and the second arm comprises a second shelf, the method further comprising:
 positioning the first and second shelves beneath the first tissue layer; and   pulling the first tissue layer away from the second tissue layer via the first and second shelves.   
     
     
         24 . The method of  claim 23 , wherein a portion of the tissue engaging device that is configured to be inserted in a patient defines a maximum outer diameter when the arms are in a retracted orientation, wherein said rotating comprises transitioning the first and second arms to an actuated orientation in which the first and second tips extend laterally outwardly by a distance greater than the maximum outer diameter.