| 摘要 |
<p>A cannula for introducing medical instruments into an anatomical cavity includes an elongate tubular body (22) defining a lumen and a valve (26) protruding distally from the tubular body for preventing fluid flow through the lumen when medical instruments are withdrawn from the anatomical cavity into the tubular body. The valves are peferably configured as one-way valves such that external forces and pressures exerted on the valves from outside the cannula will not cause the valves to open. The valves can form rounded (26) or blunt distal ends when closed or can be configured in a manner to penetrate anatomical tissue when closed. Furthermore, spring members can be embedded in the valves to provide reinformcement and to bias the valves to a closed position.</p> |
