Method for using a variable stiffness medical device

Abstract

A medical device such as an endoscope has an elongated flexible sheath. A first sleeve has a passage there through which snugly receives the sheath, the first sheath being slideable from its proximal end to its distal end. The sleeve is a thin-walled tube having a constant inner diameter so as to minimize the increase the outer dimension of the device at the portion upon which the sleeve is positioned. The sleeve has a length of approximately one-half the length of the sheath and may have greater stiffness than the sheath. A second sleeve may be slideably mounted on the first sleeve and has a snug fit therewith. The second sleeve is also a thin-walled tube having a constant outer dimension. The second sleeve has a length of approximately one-half the length of the first sleeve and may have greater stiffness than the first sleeve.

What is claimed is:  
     
         1 . A method of moving an ultrasonic medical device along an anatomical passage within a body comprising: 
 extending an elongated flexible ultrasonic probe of the ultrasonic medical device through a passage of a sleeve; and    positioning the sleeve along a portion of a length of the elongated flexible ultrasonic probe to allow the stiffness of the ultrasonic medical device to be varied and maintain sufficient residual flexibility for manipulation within the anatomical passage of the body.    
     
     
         2 . The method of  claim 1  further comprising providing the sleeve having a thin walled tube with a substantially constant outer diameter to minimize an outer diameter of the ultrasonic medical device.  
     
     
         3 . The method of  claim 1  further comprising moving the sleeve along the elongated flexible ultrasonic probe to move a location of maximum flexure of the elongated flexible ultrasonic probe.  
     
     
         4 . The method of  claim 1  further comprising forming the sleeve of a flexible material.  
     
     
         5 . The method of  claim 1  further comprising varying the taper along a portion of the length of the sleeve.  
     
     
         6 . The method of  claim 1  further comprising varying the rigidity along a portion of the length of the sleeve.  
     
     
         7 . The method of  claim 1  further comprising using the ultrasonic medical device for a single use on a single patient.  
     
     
         8 . The method of  claim 1  further comprising providing the sleeve having an at least one notch on an inner surface of the sleeve corresponding to a location of a node of the elongated flexible ultrasonic probe so the sleeve does not dampen the motion of the elongated flexible ultrasonic probe.  
     
     
         9 . The method of  claim 1  further comprising heat shrinking the sleeve onto the elongated flexible ultrasonic probe.  
     
     
         10 . The method of  claim 1  further comprising providing the sleeve having a first side softer than a second side.  
     
     
         11 . The method of  claim 1  further comprising forming the sleeve of a material having a stiffness to maintain its own column.  
     
     
         12 . A method of varying a stiffness of an ultrasonic medical device comprising: 
 extending an ultrasonic probe of the ultrasonic medical device through a passage of a first sleeve;    positioning the first sleeve along a length of the ultrasonic probe;    extending the ultrasonic probe and the first sleeve through a passage of a second sleeve; and    positioning the second sleeve relative to the first sleeve,    wherein the first sleeve and the second sleeve vary the stiffness of the ultrasonic medical device while maintaining sufficient residual flexibility of the ultrasonic medical device.    
     
     
         13 . The method of  claim 12  further comprising heat shrinking the second sleeve onto the first sleeve.  
     
     
         14 . The method of  claim 12  further comprising forming the first sleeve and the second sleeve of a flexible material.  
     
     
         15 . The method of  claim 12  further comprising providing the first sleeve and the second sleeve each having a thin walled tube having a substantially constant outer diameter to minimize an outer diameter of the ultrasonic medical device.  
     
     
         16 . The method of  claim 12  further comprising adjusting a location of maximum flexure along the ultrasonic probe by moving the first sleeve and the second sleeve along the length of the ultrasonic probe.  
     
     
         17 . The method of  claim 12  further comprising providing the first sleeve and the second sleeve having an at least one notch on an inner surface of the first sleeve and the second sleeve corresponding to a location of a node of the ultrasonic probe so the first sleeve and the second sleeve do not dampen the motion of the ultrasonic probe.  
     
     
         18 . The method of  claim 12  further comprising forming the first sleeve and the second sleeve of a material having a stiffness to maintain their own column.  
     
     
         19 . The method of  claim 12  further comprising forming the first sleeve and the second sleeve of the same material.  
     
     
         20 . The method of  claim 12  further comprising forming the first sleeve and the second sleeve of different materials.