System and method for delivering expanding trocar through a sheath

Abstract

A trocar has an elongate body and a tissue-penetrating tip. One or more radially extending blade(s) are provided near the tissue-penetrating tip of the trocar body so that they automatically open as the trocar is advanced through tissue. The blades will enlarge the penetration which was formed by the tip of the trocar.

What is claimed is: 
     
         1 . A trocar for use with a delivery sheath having a lumen, said trocar comprising:
 an elongate body which can be advanced through the sheath lumen; and   at least one blade disposed near a distal end of the elongate body, said blade being biased to open from a radially retracted configuration to a radially extended configuration, wherein the blade is radially retracted when the distal end of the elongate body is within the sheath lumen and said blade opens radially when the distal end is advanced distally beyond the sheath lumen.   
     
     
         2 . A trocar as in  claim 1 , wherein the blade closes radially in response to being drawn back into the sheath lumen. 
     
     
         3 . A trocar as in  claim 2 , wherein the blade has a proximal surface which engages a distal surface of the delivery sheath to collapse the blade as the blade is drawn proximally back into the sheath lumen. 
     
     
         4 . A trocar as in  claim 1 , further comprising means for pulling the blade back into the elongate body. 
     
     
         5 . A trocar as in  claim 1 , wherein said elongate body has a tissue-penetrating distal tip. 
     
     
         6 . A trocar as in  claim 5 , wherein the tissue penetrating tip comprises a sharpened tip. 
     
     
         7 . A trocar as in  claim 1 , wherein a single blade is pivotally mounted so that opposite ends of the blade rotate to open from opposite sides of the elongate body. 
     
     
         8 . A trocar as in  claim 7 , further comprising a tether attached to the blade, wherein the tether can be tensioned to collapse the blade prior to drawing the blade back into the sheath. 
     
     
         9 . A trocar as in  claim 7 , wherein the blade has a proximal surface which engages a distal surface of the delivery sheath causing the blade to collapse as the blade is drawn proximally back into the sheath lumen. 
     
     
         10 . A trocar as in  claim 1 , comprising at least two biased blades attached to a single pivot to open in a scissors-like pattern wherein the blades have sharpened distal edges to cut tissue as the elongate body is advanced. 
     
     
         11 . A trocar as in  claim 1 , comprising two biased blades attached to pivot points on opposite sides of the elongate body, wherein the blades are parallel to each other within the elongate body. 
     
     
         12 . A trocar as in  claim 1 , comprising two blades which are axially spaced-apart on the elongate body. 
     
     
         13 . A trocar as in  claim 12 , comprising three blades axially spaced-apart on the elongate body. 
     
     
         14 . A trocar as in  claim 1 , wherein the blade(s) comprise pre-shaped wires which expand radially outwardly when released from constraint. 
     
     
         15 . A trocar as in  claim 14 , further comprising a tether attached to the wire, wherein the tether can be tensioned to collapse the wire prior to drawing the trocar back into the sheath. 
     
     
         16 . A trocar as in  claim 1 , wherein the blade is conformed circumferentially over the surface of the elongate body, wherein the blade is attached with an axially aligned hinge. 
     
     
         17 . A method for accessing an internal body organ, said method comprising:
 introducing a delivery sheath to a location adjacent to a wall of the organ; and   advancing a trocar from a lumen in the delivery sheath, wherein the trocar penetrates the wall of the organ;   wherein advancing the trocar releases a blade from constraint within the delivery sheath lumen so that the blade opens radially as the trocar exits the lumen such that the blade enlarges the penetration made by the distal tip of the trocar.   
     
     
         18 . A method as in  claim 17 , wherein the delivery sheath is introduced through a natural body orifice. 
     
     
         19 . A method as in  claim 18 , wherein the delivery sheath is introduced transorally or transanally into the GI tract to access a cyst, pseudocyst or abscess. 
     
     
         20 . A method as in  claim 18 , wherein the delivery sheath is introduced transorally or transanally into the GI tract to access a gall bladder or a urinary bladder. 
     
     
         21 . A method as in  claim 17 , wherein the delivery sheath comprises an endoscope and the lumen comprises a working channel of the endoscope. 
     
     
         22 . A method as in  claim 17 , wherein the trocar has a tissue-penetrating tip and forms the penetration as it is advanced through the organ wall. 
     
     
         23 . A method as in  claim 17 , wherein the blade is biased to spring open as the constraint is removed. 
     
     
         24 . A method as in  claim 17 , wherein a single blade opens. 
     
     
         25 . A method as in  claim 17 , wherein a pair of laterally opposed blades open. 
     
     
         26 . A method as in  claim 18 , wherein the delivery sheath is introduced transorally or transanally into the GI tract to access the bile duct or pancreatic duct. 
     
     
         27 . A method as in  claim 18 , wherein the delivery sheath is introduced transorally or transanally into the GI tract to access an organ or structure in the abdominal, pelvic or thoracic cavity adjacent to the GI tract. 
     
     
         28 . A method as in  claim 17 , wherein the delivery sheath comprises a catheter with a length from 20 cm to 500 cm and a diameter from 1 mm to 5 mm.