A surgical access device includes a cannula body and a fixation mechanism. The cannula body includes a housing, and an elongated portion extending distally from the housing and defining a longitudinal axis. The fixation mechanism includes a flange, a fixation sleeve, and a proximal sleeve. The flange is rotatable about the longitudinal axis. The fixation sleeve extends distally from the flange and radially surrounds a portion of the elongated portion of the cannula body. The proximal sleeve extends distally from the flange and radially surrounds a proximal portion of the fixation sleeve. Rotation of the flange causes a radially-expandable portion of the fixation sleeve to move between a first position defining a first gap between the radially-expandable portion and the elongated portion, and a second position defining a second, greater, gap between the radially-expandable portion and the elongated portion.