Apparatus and methods for puncturing tissue

Abstract

An elongated medical sheath is configured to be movable and positionable proximate to a biological feature of a patient. An expandable-and-collapsible support structure is configured to be selectively movable, at least in part, between an interior of the elongated medical sheath and an exterior of the elongated medical sheath. An energy-emitting assembly is supported by the expandable-and-collapsible support structure.

What is claimed is: 
     
         1 . A surgical introducer comprising:
 an introducer shaft having a longitudinally extending rigid portion having a distal end, the rigid portion defining a lumen;   a flexible tip portion coupled to the distal end, the flexible tip portion including a first polymer and a second polymer, the second polymer being more flexible than the first polymer,   wherein the second polymer is longitudinally abutted against and extends distally from the distal end to define a second polymer flexible tip segment having a second polymer flexible tip segment end and the first polymer longitudinally abutted against and extending distally from the second polymer flexible tip segment end to define a flexible tip portion cap, the tip portion cap defining a distal opening in fluid communication with the lumen.   
     
     
         2 . The surgical introducer of  claim 1 , wherein the distal end opening is forward facing. 
     
     
         3 . The surgical introducer of  claim 1 , further comprising an outside layer of a polymer on an outside of the rigid portion. 
     
     
         4 . The surgical introducer of  claim 1 , further comprising an inside layer of polymer on portion of an inside of the rigid portion. 
     
     
         5 . The surgical introducer of  claim 1 , wherein the second polymer flexible tip segment has a length of length L 2  and the flexible tip portion cap has a length of length L 1 , such that the length L 2  is greater than the length L 1 . 
     
     
         6 . The surgical introducer of  claim 1 , wherein the flexible tip portion has a length of about 1 to 3 cm. 
     
     
         7 . The surgical introducer of  claim 1 , wherein the flexible tip portion has a length of 2 to 3 cm. 
     
     
         8 . The surgical introducer of  claim 1 , wherein the first polymer is HDPE. 
     
     
         9 . The surgical introducer of  claim 1 , wherein the second polymer is LDPE. 
     
     
         10 . The surgical introducer of  claim 1 , wherein the rigid portion is steel. 
     
     
         11 . The surgical introducer of  claim 1 , wherein the second polymer extends proximally from on an outside of the rigid portion. 
     
     
         12 . The surgical introducer of  claim 11 , wherein the second polymer defines a second polymer outside layer which has a second polymer outside layer proximal end, and the first polymer extends proximally from the second polymer outside layer proximal end on an outside of the rigid portion to define a first polymer outside layer. 
     
     
         13 . The surgical introducer of  claim 11 , wherein the second polymer flexible tip segment has a second polymer flexible tip segment length of length L 2  and the second polymer extends proximally from the distal end on the outside of the rigid portion to define a second polymer outside layer which extends longitudinally and proximally from the distal end for a distance less than length L 2 . 
     
     
         14 . The surgical introducer of  claim 13 , wherein the rigid portion has a proximal end and the second polymer outside layer extends proximally to the proximal end. 
     
     
         15 . The surgical introducer of  claim 1 , further comprising the second polymer extending proximally from the distal end on the inside of the rigid portion to define a second polymer inside layer having a second polymer inside layer proximal end. 
     
     
         16 . The surgical introducer of  claim 15 , wherein the rigid portion has a proximal end and the second polymer inside layer proximal end is distal of the rigid portion proximal end. 
     
     
         17 . The surgical introducer of  claim 16 , wherein a diameter of the lumen proximal of the second polymer inside layer is greater than the diameter of the lumen defined by the flexible tip portion. 
     
     
         18 . The surgical introducer of  claim 1 , further comprising the first polymer extending proximally from the flexible tip portion cap to form a first polymer inside layer, the first polymer inside layer defining at least a portion of the lumen. 
     
     
         19 . The surgical introducer of  claim 18 , wherein the rigid portion has a rigid portion proximal end and the first polymer inside layer extends proximally to the rigid portion proximal end. 
     
     
         20 . The surgical introducer of  claim 19 , wherein a diameter of the lumen which is defined by the rigid portion is substantially equal to the diameter of the lumen which is defined by the flexible tip portion.