| 摘要 |
An electrosurgical control (10) for a trocar (11) has a trocar (11) with a cannula (12) with a stylet (13) coaxially fit therein. The stylet (13) is movable relative to the cannula (12) along a common axis. The trocar (11) is shaped for insertion in a direction generally along the axis through tissue in a puncture procedure with its stylet (13). A distal end (15) and a proximal end (16) on the elongate cannula (12) so the distal end (15) enters the tissue while the proximal end (16) remains outside. A tip (17) on the stylet (13) end, near the distal end (15) of the cannula (12), normally extends therebeyond in position to puncture the tissue. The stylet (13) has an energy supply (18) passing from the tip (17) to its opposite end (19) and moves reciprocally relative to the cannula (12) so the tip (17) extends or is fully within the cannula (12). An electrosurgical generator (20) provides energy to the opposite end (19) of the stylet (13) and an electrosurgically active device is a part of the tip (17) and connects to the energy supply (18). A sampling circuit (21) is connected to the electrosurgically active device and responds to changes in energy passing through the energy supply (18) as a function of tissue cut by the electrosurgically active device. The sampling circuit (21) provides a signal relative to the energy supplied and a measuring circuit (22) analyzes the signal to instantly isolate a specific signal therefrom indicative of a significant change in the energy when the tip (17) is not in tissue. A comparator (23) has a settable predetermined threshold amount of energy at which the electrosurgical generator (20) no longer supplies energy. A peak energy level is set by a knob (24) and is compared to the varying signals from the sampling circuit (21). A switch (25) responds to the comparator (23) to disconnect the energy when the threshold is exceeded. |
