Abstract: A radially expandable trocar, port or cannula system is provided for use in minimally invasive surgeries. The cannula creates a port access with an initial small internal diameter. The passage of the cannula devices is defined by a plurality of elongate rigid members. A number of mechanisms are provided for expanding the passage of the cannula devices, by moving the plurality of elongate rigid members towards a larger radial location, thereby creating a larger internal diameter for the port. The elongate rigid members can be prevented from unintended movement when the system is at the un-expanded state, during expansion and when it is expanded to the desired larger diameter. Exemplary embodiments include methods of preventing gas loss from the tissue that would occur through the gaps created during expansion.

Abstract: Cannula devices, systems, and methods are provided for introducing one or more instruments into a patient's body to perform a procedure. In one example, the cannula device includes first and second housings defining a throughbore, and a plurality of elongate members extending distally from the housings, the elongate members cooperatively defining a passage axially aligned with the throughbore between proximal ends and distal tips of the elongate members. The first housing is moveable in an axial direction with respect to the second housing to cause the proximal ends of the elongate members to move outwardly to increase a size of the passage and, optionally, may taper when expanded. Optionally, one or more secondary devices, e.g., an obturator with a sharpened tip, or an obturator and tubular access device may be provided that may be inserted through the throughbore into the passage before expansion of the passage.