A surgical apparatus for positioning within a tissue tract accessing anunderlying bodycavity adapts to tissue tracts of different widths. The surgical instrumentincludes a proximalmember, a distal member, and a sleeve extending between the proximal memberand the distalmember and defining a longitudinal passage therein. The proximal memberincludes aninflatable member that selectively adjusts the radial dimension of theproximal member. A ringmember may be separately insertable by a user during a surgical procedure intothe spacedirectly adjacent to the radially-inner surface of the inflatable member, soas to selectivelyprovide rigidity to the proximal member.
