A stabilizer (10,60) is provided to secure and fix the position of a cannula assembly (26) relative to tissue. The stabilizer is a liquid swellable member (12) which expands within an incision in tissue in response to the absorption of a liquid. The stabilizer includes an inner adhesive layer to secure the stabilizer relative to a cannula assembly. The stabilizer is formed of a polymeric gel or foam. In one embodiment, the stabilizer is fixedly secured to an elongate tubular member (36) of a cannula assembly. In an alternative embodiment, the stabilizer is mounted for longitudinal movement along an elongate tubular member of a cannula assembly.
