Abstract: An attachment (1) for a trocar cannula (3) having an access valve (12) located in a proximal end (5) thereof comprises a housing (20) defining an instrument passageway (29). An operating member (43) having an instrument bore (46) is slideable in the instrument passageway (29) from a disengaged state disengaged from the access valve (12) to an engagement state extending through the access valve (12) with the access valve (12) in the open state and shielded from an instrument passing therethrough. A pair of detecting probes (55) carried on a carrier (50) and extending into the instrument bore (46) are urgeable distally from a first state to a second state by a distal end of an instrument being urged distally in the instrument bore (46) for in turn urging the operating member (43) from the disengaged state to the engagement state.

Abstract: A valve mechanism (3) for attaching to a proximal end (4) of a trocar cannula (2) for minimising leakage of insufflating and other gases proximally from the trocar cannula (2), comprises a housing (7) adapted for securing to the trocar cannula (2) adjacent the proximal end (4) thereof. The housing (7) defines an instrument bore (22) extending from a proximal end (23) to a distal end (21). A distal valve (28) is located adjacent the distal end (21) of the instrument bore (22) and is pivotal from an open state to a closed state. A proximal valve (40) is located towards the proximal end (23) of the instrument bore (22), and comprises first and second valve members (41) and (42) which are urgeable from a withdrawn state clear of the instrument bore (22) to an engagement state sealably engaging an instrument in the instrument bore (22) for sealing the instrument bore (22).