TROCAR AND CANNULA

摘要

A trocar (10) is formed from a cannula (13) and an interfitting obturator (12) for penetrating body cavity walls in laparoscopic and endoscopic surgery. The obturator (12) is provided with an improved piercing tip (80) having a pointed blade (81) and an improved locking shield (15) design. The locking mechanism must be actuated before the shield (15) will retract to expose the piercing tip (80). The shield (15) is located inside the obturator sheath (18) and provides faster coverage of the piercing tip (80) after the body cavity wall has been penetrated. The cannula (13) has an improved thread design to more easily and securely hold the cannula in the incision of the body cavity wall. A one-piece inner housing (17) is used in the cannula (13) to reduce the need for welding to prevent gas leakage. The cannula (13) also has improved seals (36) to maintain insufflation of the body cavity and an automatic insufflation valve (43) to facilitate connection to the external gas supply.