Expanding sheath tip

Abstract

A medical instrument is provided including, an expandable tip which is embedded within a sheath. The expandable tip comprises a plurality of fingers which extend distally from the embedded portion. The plurality of fingers are heat set in a first position so that the distal ends of the fingers define a distal opening, where the distal opening has a smaller diameter than the embedded portion of the expandable tip. The plurality of fingers is reversibly expandable to a second position, creating a larger distal opening to deploy an expandable accessory.

We claim: 
     
         1 . A medical device, comprising:
 a sheath comprising a lumen and an expandable tip having a plurality of fingers extending distally, each of the plurality of fingers having a distal end, wherein the plurality of fingers are heat set in a first position so that the distal ends of the plurality of fingers define a distal opening which has a distal diameter less than a proximal diameter of a proximal portion of the sheath, and wherein the plurality of fingers is reversibly expandable to a second position wherein the distal diameter is larger than in the first position; and   a catheter positioned within the lumen of the sheath, wherein the catheter has an enlarged portion projecting from an outer surface of the catheter.   
     
     
         2 . The medical device of  claim 1 , wherein the catheter comprises a proximal enlarged portion and a distal enlarged portion on the outer surface of the catheter, and wherein the catheter is arranged to receive an expandable accessory between the proximal and distal enlarged portions. 
     
     
         3 . The medical device of  claim 1 , wherein the enlarged portion of the catheter comprises a proximal portion with an incline from the outer surface extending distally and projecting outwardly from the outer surface. 
     
     
         4 . The medical device of  claim 3 , wherein the enlarged portion further comprises a distal portion with an incline from the outer surface extending proximally and projecting outwardly from the outer surface. 
     
     
         5 . The medical device of  claim 1 , wherein motion of the enlarged portion of the catheter across the expandable tip moves the plurality of fingers between the first position and the second position. 
     
     
         6 . The medical device of  claim 1 , wherein an embedded portion of the expandable tip is embedded within a wall of the sheath, and wherein the embedded portion of the expandable tip comprises at least one opening which is filled by a wall material of the sheath. 
     
     
         7 . A medical device, comprising:
 a sheath comprising a lumen and an expandable tip having a plurality of metal fingers extending distally, each of the plurality of metal fingers having a distal end, wherein the plurality of fingers are formed in a first position so that the distal ends of the plurality of fingers define a distal opening which has a distal diameter less than a proximal diameter of a proximal portion of the sheath, wherein the plurality of metal fingers are expandable to a second position; and   a catheter configured to be positioned within the lumen of the sheath.   
     
     
         8 . The medical device of  claim 7 , wherein the catheter has an enlarged portion projecting from an outer surface of the catheter, and wherein the enlarged portion is arranged within the sheath to move an expandable accessory through the expandable tip. 
     
     
         9 . The medical device of  claim 8 , wherein the catheter comprises a proximal enlarged portion and a distal enlarged portion on the outer surface of the catheter, and wherein the catheter is arranged to receive the expandable accessory between the proximal and distal enlarged portions. 
     
     
         10 . The medical device of  claim 9 , wherein the distal enlarged portion of the catheter comprises an inclined surface on a proximal side of the enlarged portion such that the expandable tip may gradually expand over the distal enlarged portion as the catheter is moved proximally relative to the sheath. 
     
     
         11 . The medical device of  claim 10 , wherein the proximal enlarged portion of the catheter comprises an inclined surface on a proximal side of the enlarged portion such that the expandable tip may gradually expand over the proximal enlarged portion as the catheter is moved proximally relative to the sheath. 
     
     
         12 . The medical device of  claim 9 , wherein the distal enlarged portion of the catheter comprises an arresting surface configured to engage expandable tip of the sheath to prevent proximal movement of the catheter relative to the sheath. 
     
     
         13 . The medical device of  claim 7 , wherein the plurality of metal fingers are reversibly expandable to the second position wherein the distal diameter is larger than in the first position. 
     
     
         14 . The medical device of  claim 7 , wherein a gap is defined between each of the plurality of fingers along a circumference of the expandable tip. 
     
     
         15 . The medical device of  claim 14 , wherein when the metal fingers are in the second position, each gap has a distal portion and a proximal portion, wherein a distal width of the distal portion is wider than a proximal width of the proximal portion. 
     
     
         16 . A medical device, comprising:
 a sheath comprising a wall which defines a lumen and an expandable distal tip, the expandable tip comprising a plurality of fingers extending distally from a proximal end to a distal end, wherein the plurality of fingers are formed in a first position so that the distal ends of the plurality of fingers define a distal opening with a first diameter which is less than a diameter of a proximal opening at the proximal end of the expandable tip, and wherein the plurality of fingers is reversibly expandable to a second position wherein the distal opening has a larger second diameter; and   a catheter configured to be positioned within the lumen of the sheath.   
     
     
         17 . The medical device of  claim 16 , wherein the plurality of fingers are embedded within an expandable covering. 
     
     
         18 . The medical device of  claim 16 , wherein the plurality of fingers are made from a metal and wherein the proximal end of the sheath is embedded within a wall of the sheath. 
     
     
         19 . The medical device of  claim 16 , wherein the catheter further comprises an enlarged portion expanding from an outer surface of the catheter. 
     
     
         20 . The medical device of  claim 19 , further comprising an expandable device configured to be positioned within the lumen of the sheath on the outer surface of the catheter, wherein the enlarged portion of the catheter is configured to advance the expandable device through the lumen of the sheath.