Devices, systems, and methods for subcutaneously placing an article

Abstract

The present invention provides devices, systems, and methods for positioning an article, such as a graft or catheter, in a subcutaneous tunnel between skin and muscle tissue of a patient to establish improved access to the patient's vascular system for hemodialysis, hemofiltration, or other extracorporeal blood treatments. In particular, the present invention provides devices, systems, and methods which minimize longitudinal forces or friction acting against the vascular graft as it is being subcutaneously positioned while still providing a tight seal between the graft and the subcutaneous tissue, which in turn minimizes hematomas, bleeding, and infections and enhances needle accessibility of the graft for extracorporeal treatment. A system for subcutaneously positioning an article comprises a tunneling tool, a pair of nested tubes coupleable to a trailing end of the tunneling tool, and a flexible article which can be slidably received within the pair of nested tubes. The nested tubes each have a leading end, a trailing end, and a longitudinal opening.

What is claimed is:  
     
         1 . A sheath for use with a tunneling tool, the sheath comprising: 
 a pair of nested tubes, each tube having a leading end, a trailing end, and a longitudinal opening; and    a coupling element attached to the leading ends of the nested tubes, the coupling element being removably attachable to a tunneling tool.    
     
     
         2 . A sheath as in  claim 1 , wherein each longitudinal opening subtends a circumferential arc of the tubes in a range from about 20° to about 190°.  
     
     
         3 . A sheath as in  claim 1 , wherein at least one tube is made from a memory alloy material.  
     
     
         4 . A sheath as in  claim 1 , wherein each tube has an external diameter in the range from about 1 mm to about 45 mm.  
     
     
         5 . A sheath as in  claim 1 , wherein the pair of nested tubes are serrated.  
     
     
         6 . A sheath as in  claim 1 , where the tubes are counter rotatable so that the openings can be selectively aligned to open a passage therein or staggered apart to close a passage therein.  
     
     
         7 . A method for subcutaneously positioning an article, the method comprising: 
 providing a trailing sheath;    inserting an article into the trailing sheath;    coupling the trailing sheath to a tunneling tool;    subcutaneously passing the tunneling tool through patient tissue to position the article at a desired location; and    removing the sheath from over the article while the article remains at the desired location.    
     
     
         8 . A method as in  claim 7 , wherein the trailing sheath comprises a pair of nested tubes, each tube having a longitudinal opening.  
     
     
         9 . A method as in  claim 8 , wherein the removing comprises withdrawing the tubes sequentially.  
     
     
         10 . A method as in  claim 8 , wherein removing comprises withdrawing an outer tube from an entrance or exit site.  
     
     
         11 . A method as in  claim 10 , wherein removing further comprises at least partially expanding an inner tube to allow release of the article at the desired location.  
     
     
         12 . A method as in  claim 11 , wherein removing further comprises withdrawing an inner tube from an entrance or exit site.  
     
     
         13 . A method as in  claim 8 , wherein removing comprises withdrawing the tubes simultaneously in opposite directions.  
     
     
         14 . A method as in  claim 8 , further comprising counter rotating the tubes so that the openings can be aligned prior to removing the sheath.  
     
     
         15 . A method as in  claim 8 , further comprising counter rotating the tubes so that the article is completely encompassed within the sheath prior to passing the tunneling tool through patient tissue.  
     
     
         16 . A method as in  claim 7 , further comprising uncoupling the tunneling tool from the trailing sheath prior to removing the sheath.  
     
     
         17 . A method as in  claim 7 , further comprising rotating the sheath so that the article can be alignable with an artery or vein prior to removing the sheath.  
     
     
         18 . A method as in  claim 7 , further comprising expanding the sheath while still encompassing the article completely prior to removing the sheath.  
     
     
         19 . A method for positioning an article in a subcutaneous tunnel, the method comprising: 
 providing a trailing sheath having a pair of nested tubes, each tube having a longitudinal opening;    inserting the article into the trailing sheath;    coupling the trailing sheath to a tunneling tool;    subcutaneously passing the tunneling tool through patient tissue to position the article at a desired location; and    removing the sheath from over the article while the article remains at the desired location by separating the nested tubes within the tunnel.