Dilating cannula with radially expandable flange and method of using the same

A dilating cannula, comprising:

• a radially expandable flange comprising two or more sectors, each of the two or more sectors being independently movable, the radially expandable flange being disposed at a proximal end portion of the dilating cannula;
• and
• an expandable shaft extending from the proximal end portion to a distal end portion of the dilating cannula, the expandable shaft defining an inner passageway of the dilating cannula and comprising two or more arms, each of the two or more arms comprising elongate longitudinal strips adjacent to the inner passageway, each of the two or more arms comprising a base section, a first branch extending from one end of the base section, and a second branch extending from another end of the base section, each base section being disposed at the distal end portion of the dilating cannula, wherein:
• the first branch is connected to a first sector of the two or more sectors of the radially expandable flange, and
• the second branch is connected to a second, different sector of the two or more sectors of the radially expandable flange.

A method for inserting a surgical device in an opening formed in a body cavity, the method comprising:

• forming an opening in a body cavity by inserting at least part of a surgical assembly in the body cavity, the surgical assembly comprising a dilating cannula over a needle-tipped obturator, the dilating cannula comprising a radially expandable flange disposed at a proximal end portion of the dilating cannula and an expandable shaft extending from the proximal end portion to a distal end portion of the dilating cannula, and the radially expandable flange being located outside of the opening;
• removing the needle-tipped obturator from the surgical assembly while maintaining at least part of the expandable shaft of the dilating cannula within the opening of the body cavity;
• and
• inserting a surgical tool within the dilating cannula, wherein the surgical tool has a dimension in an axis perpendicular to a center axis of the surgical tool, wherein:
• the dimension of the surgical tool is greater than a dimension of the expandable shaft of the dilating cannula in the axis perpendicular to the center axis of the surgical assembly, and
• insertion of the surgical tool causes expansion of both the radially expandable flange and the expandable shaft of the dilating cannula.