Catheter tunneling systems, instruments and methods

1. An instrument for facilitating insertion of a catheter through a subcutaneous tunnel, which comprises:

a tunneling stylet having first and second segments, the first segment defining a longitudinal axis along at least a portion of a length thereof, the second segment being dimensioned for passage through tissue;

a bifurcated segment releasably connectable to the first segment, the bifurcated segment including first and second elements adapted for reception within respective lumens of the catheter; and

a dilation member releasably connectable to the first segment in the absence of the bifurcated segment, the dilation member dimensioned to generally increase an internal dimension of the subcutaneous tunnel,

wherein the first segment of the tunneling stylet and the dilation member include cooperative threaded portions for establishing a releasable connection therebetween,

the dilation member includes a trailing segment, an intermediate segment and a leading segment, and the dilation member defines an internal thread on an inner surface thereof configured to engage with an external thread on the first segment of the tunneling stylet, and

the trailing segment of the dilation member includes a first tapered segment and a first cylindrical segment, and the intermediate segment includes a second tapered segment, a second cylindrical segment and a third segment, the leading segment having a cylindrical configuration.

2. The instrument according to claim 1 , wherein the first and second elements of the bifurcated segment define first and second longitudinal lengths, the first longitudinal length being greater than the second longitudinal length.

3. The instrument according to claim 1 , wherein the first and second elements of the bifurcated segment each include a locking rib protruding outwardly with respect to the longitudinal axis from an outer surface of the corresponding first and second elements, each locking rib being dimensioned to facilitate gripping engagement with an internal surface of respective lumens of the catheter.

4. The instrument according to claim 1 , wherein the first segment of the tunneling stylet and the bifurcated segment include cooperative threaded portions for establishing a releasable connection therebetween.

5. The instrument according to claim 1 , wherein the second segment of the tunneling stylet extends from the first segment of the tunneling stylet and is obliquely arranged with respect to the longitudinal axis.

6. The instrument according to claim 5 , wherein the second segment of the tunneling stylet defines a tapered configuration extending in a direction away from the longitudinal axis.

7. The instrument according to claim 1 , wherein the bifurcated segment has a collar from which the first and second elements of the bifurcated segment extend, the collar configured for flush engagement against an end face of the catheter.

8. The instrument according to claim 1 , wherein the first and second elements of the bifurcated segment are parallel to the longitudinal axis when the bifurcated segment is connected to the first segment of the tunneling stylet.

9. A system comprising:

a catheter defining first and second lumens;

a tunneling stylet having first and second segments, the first segment defining a longitudinal axis along at least a portion of a length of the first segment, the second segment being dimensioned for passage through tissue;

a bifurcated segment releasably connectable to the first segment, the bifurcated segment including first and second elements positionable within respective lumens of the catheter; and

a dilation member releasably connectable to the first segment in the absence of the bifurcated segment,

wherein the dilation member includes a trailing segment, an intermediate segment and a leading segment, and the dilation member defines an internal thread on an inner surface, an external surface of the first segment of the tunneling stylet defines an external thread engageable with the internal thread to releasably secure the dilation member to the tunneling stylet, and

the trailing segment of the dilation member includes a first tapered segment and a first cylindrical segment, and the intermediate segment includes a second tapered segment, a second cylindrical segment and a third segment, the leading segment having a cylindrical configuration.

10. The system of claim 9 , wherein the catheter includes a cuff circumscribing the catheter and the dilation member is sized to create a shelf in a wearer's tissue for accommodating the cuff.