Method and apparatus for induction of pneumoperitoneum

摘要

A method and apparatus for induction of pneumoperitoneum and insertion of a laparoscopic sheath is provided in which a trocar carrying a sheath or cannula has a tapered distal end with screw threads formed on the outer surface of the distal end. The distal tip or end terminates in a short flexible tube. A hollow needle extends through a central passageway in the trocar and through the flexible tip on the trocar. The opposite end of the hollow needle is provided with a pressure chamber which is in fluid communication with the passageway in the needle. In use, the trocar and cannula are screwed into the body tissues of the patient and when the distal end of the needle enters the peritoneal space within the body, liquid within the pressure chamber passes through the hollow needle and into the peritoneal space. The release of the fluid from the pressure chamber is an indicator to the surgeon that the end portion of the needle has entered the peritoneal space. The trocar and cannula are then screwed in as the needle is withdrawn from the flexible tip on the distal end of the trocar so as to prevent damage to any body tissues. Induction of an adequate pneumoperitoneum may then take place after verifying proper placement of the trocar and cannula. Instruments suitable for laparoscopic surgery may be inserted through the cannula or sheath.