Abstract: A method for accessing the peritoneal cavity without using a trocar. A cannula is provided having screw threads on its outer surface, a distal end, a proximal end, a body portion between the distal and proximal ends, a centrally positioned lumen extending throughout the length of the cannula and a hook. A small incision is made in the skin and underlying tissues down to the anterior fascia and a smaller opening is made in the anterior fascia to receive the hook. The hook is inserted through the opening in the anterior fascia and the proximal end of the cannula is rotated in the same direction in which the point of the hook is directed so that the cannula stretches the opening in the anterior fascia enough to accommodate the body portion of the cannula while maintaining an airtight seal around the body portion of the cannula. During rotation, the body portion of the cannula passes through the layers of the abdominal wall until the distal end of the cannula is disposed within the peritoneal cavity.

Abstract: A cannula for safely and easily gaining access to a body cavity without the use of a trocar, has screw threads on its outer surface and a lumen within the cannula extending throughout the entire length of the cannula. The distal end of the cannula is shaped, along its periphery, to penetrate and/or cut tissue layers of the body wall to gain access to a body cavity. The lumen is sufficiently large throughout its length to allow passage of instruments from the proximal end of the cannula directly into the body cavity, once the cannula has been inserted. A method for gaining access to a body cavity with the cannula is also described.