| 摘要 |
An electrosurgical control for a trocar has a trocar with a cannula with a stylet coaxially fit therein. The stylet is movable relative to the cannula along a common axis. The trocar is shaped for insertion in a direction generally along the axis through tissue in a puncture procedure with its stylet. A distal end and a proximal end on the elongate cannula so the distal end enters the tissue while the proximal end remains outside. A tip on the stylet end, near the distal end of the cannula, normally extends therebeyond in position to puncture the tissue. The stylet has an energy supply passing from the tip to its opposite end and moves reciprocally relative to the cannula so the tip extends or is fully within the cannula. An electrosurgical generator provides energy to the opposite end of the stylet and an electrosurgically active device is a part of the tip and connects to the energy supply. A sampling circuit connected to the electrosurgically active device and responds to changes in energy passing through the energy supply as a function of tissue cut by the electrosurgically active device. The sampling circuit provides a signal relative to the energy supplied and a measuring circuit analyzes the signal to instantly isolate a specific signal therefrom indicative of a significant change in the energy when the tip is not in tissue. A comparator has a settable predetermined threshold amount of energy at which the electrosurgical generator no longer supplies energy. A peak energy level is set by a knob and is compared to the varying signals from the sampling circuit. A switch responds to the comparator to disconnect the energy when the threshold is exceeded. |
