The trocar for use in a minimally invasive surgical procedure comprises an elongated body having a generally tubular configuration with coaxially arranged inner and outer walls (120, 110). The body has longitudinally opposed proximal and distal end portions. The inner wall defines a lumen to accommodate passage of an instrument therethrough. The trocar further comprises nozzle means operatively associated with the inner wall (120) of the body for directing pressurized fluid into the lumen to develop a pressure differential in an area within a region extending from a location adjacent a distal end portion of the lumen to a location adjacent a proximal end portion of the lumen. The nozzle means is adapted to form a fluid seal around an instrument passing through the lumen, and there are means for delivering a pressurized flow of fluid to the nozzle means. The nozzle means is substantially annular and is defined between the inner tubular member (120) and an inner tubular insert (130) separated by standoffs (135) to maintain a desired nozzle width.
