| 摘要 |
The invention relates to a cannula system for introducing endoscopic tools in a human or animal body. Said system comprises a hollow cannula (1) which forms a transit channel inside the body after penetrating the skin layers, as well as a mandrel (8) which can be inserted into said hollow cannula (1). The inventive cannula system is characterised in that the hollow cannula (1) has an outer wall (3) with a coaxial screw-type profile surrounding the longitudinal axis of the cannula in a helical manner and in that the mandrel (8) is provided in the form of a straight cylinder allowing the hollow cannula (1) to penetrate the skin layers. The mandrel has an outer profile which matches the inner profile of the hollow cannula (1) so that the mandrel (8) can be precisely inserted in the hollow cannula (1) and is provided with a conical distal tip (10) from which a screw thread (11) widens in a helical manner, whereby the shape, volume and size of said screw thread corresponds to the helical thread (2) of the outer wall (3) of the hollow cannula (1), at the transition between said conical tip (10) and the mandrel (8) in the form of a straight cylinder. |
