An instrument for facilitating insertion of a catheter through a subcutaneous tunnel includes a tunneling stylet defining a longitudinal axis and having leading and trailing ends, a bifurcated segment adjacent the leading end of the tunneling stylet and a releasable cover releasably mountable to the leading end of the tunneling stylet to substantially enclose the bifurcated segment. The bifurcated segment includes first and second elements adapted for reception within respective lumens of a catheter. The instrument may further include a dilation member which is releasably mountable to the leading end of the tunneling stylet in the absence of the releasable cover. The dilation member is dimensioned to generally increase an internal dimension of the subcutaneous tunnel. The first and second elements of the bifurcated segment each include an outer peripheral rib dimensioned to facilitate gripping engagement with an internal surface of respective lumens of the catheter. The first and second elements of the bifurcated segment may include a plurality of spaced outer peripheral ribs dimensioned to facilitate gripping engagement with internal surfaces of respective lumens of the catheter. In an alternative embodiment, the bifurcated segment is releasably mountable to the tunneling stylet. Systems and methods of use of the tunneling instrument are also disclosed.
