Expandable transluminal sheath

Abstract

Disclosed is an expandable transluminal sheath, for introduction into the body while in a first, low cross-sectional area configuration, and subsequent expansion of at least a part of the distal end of the sheath to a second, enlarged cross-sectional configuration. The distal end of the sheath is maintained in the first, low cross-sectional configuration and expanded using a radial dilatation device. In an exemplary application, the sheath is utilized to provide access for diagnostic or therapeutic procedures such as ureteroscopy, cardiac electrophysiology, gastroenterology, and spinal access.

1 . An expandable medical access sheath for providing minimally invasive access to body lumens or cavities, comprising: 
 a length of proximal sheath tubing, said proximal sheath tubing being non-expandable;    a length of distal sheath tubing, said distal sheath tubing being collapsed to a diameter smaller than that of the proximal sheath tubing;    a transition zone between the distal sheath tubing and the proximal sheath tubing, wherein the transition zone tapers between the larger diameter proximal sheath tubing and the smaller diameter distal sheath tubing; and    a dilator disposed within both the proximal sheath tubing and the distal sheath tubing, wherein radial expansion of the dilator causes the distal sheath tubing to expand diametrically to substantially the same inner diameter as that of the proximal sheath tubing.    
   
   
       2 . The sheath of  claim 1  wherein, following dilation, the sheath has a full internal lumen that reaches from the proximal end to the distal end.  
   
   
       3 . The sheath of  claim 1  further comprising a hub affixed at the proximal end of the sheath, wherein said hub provides for grasping the sheath and for infusion and withdrawal of fluids from said sheath.  
   
   
       4 . The sheath of  claim 1  further comprising a hub affixed to the proximal end of the dilator, wherein said hub provides for grasping of the dilator, for the infusion and withdrawal of fluids from the dilator, and for locking the hub of the dilator to a hub affixed to the proximal end of the sheath.  
   
   
       5 . The sheath of  claim 1  wherein the distal sheath tubing is composite in structure.  
   
   
       6 . The sheath of  claim 1  wherein the proximal sheath tubing is composite in structure.  
   
   
       7 . The sheath of  claim 1  wherein the composite structure of the distal sheath tubing comprises a malleable reinforcement embedded within the outer and inner surface of the distal sheath tubing.  
   
   
       8 . The sheath of  claim 7  wherein the malleable reinforcement is a coil of wire.  
   
   
       9 . The sheath of  claim 7  wherein the malleable reinforcement is an expandable stent.  
   
   
       10 . The sheath of  claim 1  wherein the dilator is removed from the sheath prior to passing instruments through the sheath.  
   
   
       11 . The sheath of  claim 1  wherein the dilator remains within the sheath while passing instruments through the sheath.  
   
   
       12 . The sheath of  claim 11  wherein the dilator is a translational dilator and is in the form of a hollow tube.  
   
   
       13 . The sheath of  claim 11  wherein the distal end of the sheath is unreinforced and does not exert substantial radial force without the presence of the dilator.  
   
   
       14 . The sheath of  claim 10  wherein the distal end of the sheath is unreinforced and does not exert substantial radial force without the presence of the dilator.  
   
   
       15 . A method of instrumenting a body lumen comprising the steps of: 
 inserting a dilator into a sheath, said sheath having a radially collapsible distal end;    collapsing the distal end of the sheath radially inward around the dilator such that the distal end of the sheath is smaller in diameter than the proximal end of the sheath;    inserting the sheath and dilator into the body lumen and advancing said sheath to a target treatment site;    expanding the dilator, wherein the dilator expansion causes the distal end of the sheath to expand to a diameter substantially the same as that of the proximal end of the sheath;    removing the dilator, wherein a central lumen remains that is substantially the same diameter moving from the proximal end to the distal end of the sheath; and    introducing instruments or catheters through the central lumen of the sheath for a therapeutic or diagnostic procedure.    
   
   
       16 . The method of  claim 15  further comprising the step of removing the sheath from the body lumen, following completion of the procedure.  
   
   
       17 . The method of  claim 15  further comprising the step of introducing a guidewire into the body lumen prior to introducing the sheath into the body lumen.  
   
   
       18 . The method of  claim 17  further comprising the step of introducing the dilator and sheath over the guidewire, wherein the guidewire passes through a lumen in the dilator.  
   
   
       19 . The method of  claim 15  further comprising the step of collapsing the distal end of the sheath prior to removing the sheath from the body lumen.  
   
   
       20 . An apparatus adapted for instrumenting a body lumen of a patient comprising: 
 a sheath having a proximal end and a distal end;    means for radially collapsing the distal end of a sheath and maintaining said radially collapsed configuration;    means for introducing the sheath into the body lumen while the distal end is in its radially collapsed configuration;    means for dilating the radially collapsed distal end of the sheath;    means for maintaining the dilated configuration of the distal end of the sheath, following dilation by the dilator;    means for performing instrumentation, material introduction or withdrawal from the body lumen through the sheath; and    means for removal of the sheath from the body lumen.    
   
   
       21 . The apparatus of  claim 20  further comprising means to track the sheath over a guidewire.  
   
   
       22 . The apparatus of  claim 20  further comprising lubricious coating on the exterior of the sheath.  
   
   
       23 . The apparatus of  claim 20 , wherein the means for dilating the distal portion of the sheath is capable of generating a minimum of 7 atmospheres of pressure within the expandable distal portion.  
   
   
       24 . The apparatus of  claim 20  wherein the radially expandable distal portion is capable of bending through tortuosity and radii less than 2 cm without substantial distortion or kinking, prior to being radially expanded.  
   
   
       25 . A device adapted for providing therapeutic or diagnostic access to a kidney through the ureter comprising a sheath having a non-expandable proximal end and a radially expandable distal end that can be expanded from an outer diameter of about 10 French or smaller to an outer diameter of greater than about 12 French.  
   
   
       26 . The device of  claim 27  wherein the overall sheath length is between 25 and 150 cm.  
   
   
       27 . The device of  claim 25  wherein the length of the expandable distal end of the sheath is between 1 and 50 cm.