| 摘要 |
A safety trocar is provided which includes a spring-loaded shield (32) that shields the cutting tip of the obturator after the obturator penetrates tissue. The distal end (34) of the shield is hemispheric in profile and contains a slot which conforms to the geometry of the 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. A valve is located at the proximal end of the trocar tube to seal the end of the tube. The valve is oriented at an acute angle with respect to the longitudinal axis of the trocar tube. The valve is controllable by an external lever which will hold the valve open or permit it to spring shut. An incremental advancement mechanism cooperates with the obturator to permit only incremental advance of the obturator. Instead of using a discrete shield component the shielding function may be provided by spring-loading the trocar tube itself to spring forward and shield the obturator tip after the tip penetrates tissue. |
