| 摘要 |
A safety trocar (1) is provided which includes a spring-loaded shield (30) that shields the cutting tip (28) of the obturator after the obturator penetrates tissue (T). The distal end of the shield is hemispheric in profile and slides within cutting tip. The rounded distal end enables the shield to spring forward to shield the cutting tip as soon as the tip perforates the tissue. In other embodiments, positive mechanical means effect shielding, using a groove (134) which forms a cam surface to be followed by a pin (126) provided on the obturator. Control means are disclosed whereby the obturator tip is caused to be exposed from the shield by motion relative thereto, when shield and obturator are placed in the cannula. |
