Abstract: Disclosed herein is an obturator and/or cannula configured for insertion of a trocar assembly into a surgical cavity and allowing insertion of medical instruments into the surgical cavity through the cannula after removal of the obturator. The cannula can include an obturator for use in a trocar assembly. A trocar assembly is disclosed including a cannula having a shaft, optionally with a lumen, and one or more elements protruding outwardly from a surface of the lumen and an obturator. The obturator can comprise a shaft with one or more portions configured to accommodate the one or more elements protruding from the lumen surface when the obturator shaft is located in the lumen of the cannula.

Abstract: Disclosed herein is a cannula and/or medical instrument accessory configured for providing localized insufflation or venting of gases with respect to a surgical cavity of a patient (such as the pneumoperitoneum) and allowing insertion of medical instruments into the surgical cavity through the cannula. A medical instrument accessory such as a cannula and/or medical instrument accessory can be used for localizing insufflation or venting of gas or fluid near operating end of a medical instrument. The medical instrument accessory can comprise a body mountable over at least a portion of a medical instrument shaft, the body having an inner lumen, proximal end and distal end, the distal end comprising an opening, wherein the distal end is arranged in use at or adjacent an operating end of the medical instrument.