A magnet assisted surgical device, system, and method employs magnetic sections, catheters, and guidewires to modify tubular stentgrafts in-situ. One example application provides a more reliable way for surgeons to modify stentgrafts insitu to allow blood flow to continue to branching blood vessels that would otherwise be blocked by the stentgraft itself. One such method includes placing a tip section of the device in the desired location, deploying a stentgraft, placing a magnetic device inside the stentgraft, connecting the magnetic device to the tip section, and excising the portion of the stentgraft held between the magnet and the tip section.
