Extravascular medical access tools having boring tip and methods of using such tools

A tool for creating a sub-sternal tunnel in a patient, the tool comprising a handle and a tunneling assembly, the tunneling assembly comprising:

• a relatively rigid tubular member including a proximal portion and a distal portion, the proximal portion being attached to the handle such that the distal portion extends distally from the handle;
• an elongate inner member extending within the tubular member and comprising:
• a proximal portion protruding out from the proximal portion of the tubular member and being attached to the handle, the proximal portion of the inner member including an interface for receiving a force that rotates the inner member relative to the tubular member;
• and
• a boring tip without any sharp edge, the tip protruding out from the distal portion of the tubular member and generally conforming to a dome shape but including at least one surface recessed from the dome shape, each of the at least one surface being offset from a summit of the dome shape, the summit of the dome shape coinciding with a distal-most edge of the boring tip.