Patent ID: 9737671
Date: 2017-08-22
CPC Classifications: A61B,A61M

Claim:
1. A trocar assembly comprising: an instrument for performance of a medical function within a body cavity wherein a portion of the instrument is located external to the body cavity and a further portion is located internal to the body cavity; and a cannula having a cyclic polygonal tube with a cyclic polygonal external shape for receiving the instrument, said a cyclic polygonal tube having a set of elongated concave panels each having a body tissue engaging inwardly concaving exterior surface and an edge with each of the edges integrally joined to an adjacent web at a radiused corner to form a polygonal lumen within the cannula with the cannula having at least three corners, said cannula comprises a different geometrical cross sectional shape then the cross sectional shape of the instrument with the instrument rotationally positionable within the cannula to provide a set of circumferential spaced peripheral gas passages between an inner surface of the cannula and an exterior surface of the instrument.