having an inner lumen and proximal and distal ends, a first cylindrical sealing plug positioned within the lumen of the cylindrical tubing at the distal end of the tubing, a second cylindrical sealing plug positioned within the lumen of the cylindrical tubing and spaced apart at a predetermined distance proximally from the first sealing plug so as to define a cavity between the first and second sealing plugs, a fluid passageway extending through the second sealing plug, and connector means connected to the proximal end of the catheter and having a lumen which is in fluid communication with the passageway of the second sealing plug so that fluid under pressure may be applied to the connector means to fill the cavity between the first and second sealing plugsto thereby stiffen the catheter in a region between the first and second sealing plugs.
Also, the catheter preferably includes a cylindrical spacer disposed between the first and second sealing plugs to maintain the predetermined distance between the sealing plugs.
Still further, the cylindrical spacer has a central axis which is coaxial with the central axis of the first and second sealing plugs and the outside diameter of the cylindrical spacer is less than the diameter of the inner lumen of the cylindrical tubing of the catheter.
In addition, preferably the passageway which extends through the second sealing plug is defined by the wall of a longitudinal slot which extends through the second sealing tube and an adjacent portion of the wall of the inner lumen of the cylindrical tubing of