Trocar assembly with pneumatic sealing

A trocar assembly comprising:

• a) an elongated outer tubular member having opposed proximal and distal end portions and having a longitudinal axis extending therethrough;
• b) an elongated inner tubular member having opposed proximal and distal end portions and being arranged coaxially within the elongated outer tubular member so as to form an annular gas flow passage therebetween, wherein a distal end portion of the trocar assembly defines an annular nozzle arrangement including an array of radially outwardly extending triangular jets arranged to direct humidified insufflation gas flowing through the annular gas flow passage into a patient's body cavity, wherein a base of each triangular jet extends over an arcuate section of the annular gas flow passage that is defined between the elongated inner tubular member and the elongated outer tubular member;
• c) a supply conduit for delivering the humidified insufflation gas to the annular gas flow passage;
• and
• d) a pressure source communicating with the supply conduit for regulating a supply of the humidified insufflation gas to the annular gas flow passage based on body cavity pressure sensed by a pressure sensor.