A thin sheath of flexible, flaccid material is introduced through openings in the body of an animal or human patient to permit surgical tools or fluids to be inserted and removed, or debris removed, during surgeries anywhere in the body to protect the tissue of the body from the instruments used. The sheath is inserted by an obturator which holds the sheath thereon by suction through an aperture in the obturator at its distal end. Once the sheath is inserted, suction is removed to release the sheath. Then a balloon on the distal end of the sheath is expanded to hold the sheath in place in the body while the obturator is removed. The sheath then remains in place with the balloon holding the distal end in the open position to enable fluids to flow through the sheath. After a procedure, the balloon is deflated and the sheath removed.